Add a demo for path ops

Implement boolean operations on paths.

demos/gtk-demo/cursors.c

@@ -24,6 +24,7 @@ do_cursors (GtkWidget *do_widget)
 
       builder = gtk_builder_new_from_resource ("/cursors/cursors.ui");
       window = GTK_WIDGET (gtk_builder_get_object (builder, "window"));
+      g_object_add_weak_pointer (G_OBJECT (window), (gpointer *)&window);
       gtk_window_set_display (GTK_WINDOW (window),
                               gtk_widget_get_display (do_widget));
       g_signal_connect (window, "destroy",
@@ -34,9 +35,7 @@ do_cursors (GtkWidget *do_widget)
   if (!gtk_widget_get_visible (window))
     gtk_widget_show (window);
   else
-    {
-      gtk_window_destroy (GTK_WINDOW (window));
-    }
+    gtk_window_destroy (GTK_WINDOW (window));
 
   return window;
 }

demos/gtk-demo/curve-editor.h

@@ -0,0 +1,36 @@
+#pragma once
+
+#include <gtk/gtk.h>
+
+G_BEGIN_DECLS
+
+#define CURVE_TYPE_EDITOR (curve_editor_get_type ())
+G_DECLARE_FINAL_TYPE (CurveEditor, curve_editor, CURVE, EDITOR, GtkWidget)
+
+GtkWidget *       curve_editor_new              (void);
+
+void              curve_editor_set_edit         (CurveEditor *self,
+                                                 gboolean     edit);
+
+void              curve_editor_set_path         (CurveEditor *self,
+                                                 GskPath     *path);
+
+GskPath *         curve_editor_get_path         (CurveEditor *self);
+
+void              curve_editor_set_stroke       (CurveEditor *self,
+                                                 GskStroke   *stroke);
+
+const GskStroke * curve_editor_get_stroke       (CurveEditor *self);
+
+
+void              curve_editor_set_color        (CurveEditor *self,
+                                                 GdkRGBA     *color);
+
+const GdkRGBA *   curve_editor_get_color        (CurveEditor *self);
+
+gboolean          curve_editor_get_show_outline (CurveEditor *self);
+
+void              curve_editor_set_show_outline (CurveEditor *self,
+                                                 gboolean     show_outline);
+
+G_END_DECLS

demos/gtk-demo/curve.c

@@ -0,0 +1,272 @@
+/* Path/Curve Editor
+ *
+ * This demo shows an elaborate curve editor that you would expect to find
+ * in a vector graphics editor. It is built on top of GTK's path APIs.
+ */
+
+#include <gtk/gtk.h>
+#include "curve-editor.h"
+
+
+static GskPath *
+make_circle_path (void)
+{
+  float w = 310;
+  float h = 310;
+  float cx = w / 2;
+  float cy = h / 2;
+  float pad = 20;
+  float r = (w - 2 * pad) / 2;
+  float k = 0.55228;
+  float kr = k  * r;
+  GskPathBuilder *builder;
+
+  builder = gsk_path_builder_new ();
+
+  gsk_path_builder_move_to (builder,  cx, pad);
+  gsk_path_builder_curve_to (builder, cx + kr, pad,
+                                      w - pad, cy - kr,
+                                      w - pad, cy);
+  gsk_path_builder_curve_to (builder, w - pad, cy + kr,
+                                      cx + kr, h - pad,
+                                      cx, h - pad);
+  gsk_path_builder_curve_to (builder, cx - kr, h - pad,
+                                      pad, cy + kr,
+                                      pad, cy);
+  gsk_path_builder_curve_to (builder, pad, cy - kr,
+                                      cx - kr, pad,
+                                      cx, pad);
+  gsk_path_builder_close (builder);
+
+  return gsk_path_builder_free_to_path (builder);
+}
+
+static void
+edit_changed (GtkToggleButton *button,
+              GParamSpec      *pspec,
+              CurveEditor     *editor)
+{
+  curve_editor_set_edit (editor, gtk_toggle_button_get_active (button));
+}
+
+static void
+reset (GtkButton   *button,
+       CurveEditor *editor)
+{
+  GskPath *path;
+
+  path = make_circle_path ();
+  curve_editor_set_path (editor, path);
+  gsk_path_unref (path);
+}
+
+static void
+line_width_changed (GtkSpinButton *spin,
+                    CurveEditor   *editor)
+{
+  GskStroke *stroke;
+
+  stroke = gsk_stroke_copy (curve_editor_get_stroke (editor));
+  gsk_stroke_set_line_width (stroke, gtk_spin_button_get_value (spin));
+  curve_editor_set_stroke (editor, stroke);
+  gsk_stroke_free (stroke);
+}
+
+static void
+cap_changed (GtkDropDown *combo,
+             GParamSpec  *pspec,
+             CurveEditor *editor)
+{
+  GskStroke *stroke;
+
+  stroke = gsk_stroke_copy (curve_editor_get_stroke (editor));
+  gsk_stroke_set_line_cap (stroke, (GskLineCap)gtk_drop_down_get_selected (combo));
+  curve_editor_set_stroke (editor, stroke);
+  gsk_stroke_free (stroke);
+}
+
+static void
+join_changed (GtkDropDown *combo,
+              GParamSpec  *pspec,
+              CurveEditor *editor)
+{
+  GskStroke *stroke;
+
+  stroke = gsk_stroke_copy (curve_editor_get_stroke (editor));
+  gsk_stroke_set_line_join (stroke, (GskLineJoin)gtk_drop_down_get_selected (combo));
+  curve_editor_set_stroke (editor, stroke);
+  gsk_stroke_free (stroke);
+}
+
+static void
+color_changed (GtkColorChooser *chooser,
+               GParamSpec      *pspec,
+               CurveEditor     *editor)
+{
+  GdkRGBA color;
+
+  gtk_color_chooser_get_rgba (chooser, &color);
+  curve_editor_set_color (editor, &color);
+}
+
+static void
+stroke_toggled (GtkCheckButton *button,
+                CurveEditor    *editor)
+{
+  curve_editor_set_show_outline (editor, gtk_check_button_get_active (button));
+  gtk_widget_queue_draw (GTK_WIDGET (editor));
+}
+
+static void
+limit_changed (GtkSpinButton *spin,
+               CurveEditor   *editor)
+{
+  GskStroke *stroke;
+
+  stroke = gsk_stroke_copy (curve_editor_get_stroke (editor));
+  gsk_stroke_set_miter_limit (stroke, gtk_spin_button_get_value (spin));
+  curve_editor_set_stroke (editor, stroke);
+  gsk_stroke_free (stroke);
+}
+
+static void
+dashes_changed (GtkEntry    *entry,
+                GParamSpec  *spec,
+                CurveEditor *editor)
+{
+  const char *text;
+  char **split;
+  GArray *dash;
+  GskStroke *stroke;
+
+  text = gtk_editable_get_text (GTK_EDITABLE (entry));
+  split = g_strsplit (text, " ", 0);
+
+  dash = g_array_new (FALSE, FALSE, sizeof (float));
+  for (int i = 0; split[i] != NULL; i++)
+    {
+      double d;
+      char *endp = 0;
+
+      d = g_strtod (split[i], &endp);
+      if (*endp == '\0')
+        g_array_append_vals (dash, (float[1]) { d }, 1);
+    }
+
+  g_strfreev (split);
+
+  stroke = gsk_stroke_copy (curve_editor_get_stroke (editor));
+  gsk_stroke_set_dash (stroke, (const float *)dash->data, dash->len);
+  curve_editor_set_stroke (editor, stroke);
+  gsk_stroke_free (stroke);
+
+  g_array_free (dash, TRUE);
+}
+
+GtkWidget *
+do_curve (GtkWidget *do_widget)
+{
+  static GtkWidget *window = NULL;
+  GtkWidget *demo;
+  GtkWidget *edit_toggle;
+  GtkWidget *reset_button;
+  GtkWidget *titlebar;
+  GtkWidget *stroke_toggle;
+  GtkWidget *line_width_spin;
+  GtkWidget *stroke_button;
+  GtkWidget *popover;
+  GtkWidget *grid;
+  GtkWidget *cap_combo;
+  GtkWidget *join_combo;
+  GtkWidget *color_button;
+  GtkWidget *limit_spin;
+  GtkWidget *dash_entry;
+
+  if (!window)
+    {
+      window = gtk_window_new ();
+      gtk_window_set_title (GTK_WINDOW (window), "Curve Editor");
+      g_object_add_weak_pointer (G_OBJECT (window), (gpointer *)&window);
+      gtk_window_set_default_size (GTK_WINDOW (window), 310, 350);
+
+      edit_toggle = gtk_toggle_button_new ();
+      gtk_button_set_icon_name (GTK_BUTTON (edit_toggle), "document-edit-symbolic");
+
+      reset_button = gtk_button_new_from_icon_name ("edit-undo-symbolic");
+
+      stroke_button = gtk_menu_button_new ();
+      gtk_menu_button_set_icon_name (GTK_MENU_BUTTON (stroke_button), "open-menu-symbolic");
+      popover = gtk_popover_new ();
+      gtk_menu_button_set_popover (GTK_MENU_BUTTON (stroke_button), popover);
+
+      grid = gtk_grid_new ();
+      gtk_grid_set_row_spacing (GTK_GRID (grid), 6);
+      gtk_grid_set_column_spacing (GTK_GRID (grid), 6);
+      gtk_popover_set_child (GTK_POPOVER (popover), grid);
+
+      gtk_grid_attach (GTK_GRID (grid), gtk_label_new ("Color:"), 0, 0, 1, 1);
+      color_button = gtk_color_button_new_with_rgba (&(GdkRGBA){ 0., 0., 0., 1.});
+      gtk_grid_attach (GTK_GRID (grid), color_button, 1, 0, 1, 1);
+
+      gtk_grid_attach (GTK_GRID (grid), gtk_label_new ("Line width:"), 0, 1, 1, 1);
+      line_width_spin = gtk_spin_button_new_with_range (1, 20, 1);
+      gtk_spin_button_set_value (GTK_SPIN_BUTTON (line_width_spin), 1);
+      gtk_grid_attach (GTK_GRID (grid), line_width_spin, 1, 1, 1, 1);
+
+      gtk_grid_attach (GTK_GRID (grid), gtk_label_new ("Line cap:"), 0, 2, 1, 1);
+      cap_combo = gtk_drop_down_new_from_strings ((const char *[]){"Butt", "Round", "Square", NULL});
+      gtk_grid_attach (GTK_GRID (grid), cap_combo, 1, 2, 1, 1);
+
+      gtk_grid_attach (GTK_GRID (grid), gtk_label_new ("Line join:"), 0, 3, 1, 1);
+      join_combo = gtk_drop_down_new_from_strings ((const char *[]){"Miter", "Miter-clip", "Round", "Bevel", "Arcs", NULL});
+      gtk_grid_attach (GTK_GRID (grid), join_combo, 1, 3, 1, 1);
+
+      gtk_grid_attach (GTK_GRID (grid), gtk_label_new ("Miter limit:"), 0, 4, 1, 1);
+      limit_spin = gtk_spin_button_new_with_range (0, 10, 1);
+      gtk_spin_button_set_digits (GTK_SPIN_BUTTON (limit_spin), 1);
+      gtk_spin_button_set_value (GTK_SPIN_BUTTON (limit_spin), 4);
+      gtk_grid_attach (GTK_GRID (grid), limit_spin, 1, 4, 1, 1);
+
+      gtk_grid_attach (GTK_GRID (grid), gtk_label_new ("Dashes:"), 0, 5, 1, 1);
+      dash_entry = gtk_entry_new ();
+      gtk_grid_attach (GTK_GRID (grid), dash_entry, 1, 5, 1, 1);
+
+      stroke_toggle = gtk_check_button_new_with_label ("Show outline");
+      gtk_grid_attach (GTK_GRID (grid), stroke_toggle, 1, 6, 1, 1);
+
+      titlebar = gtk_header_bar_new ();
+      gtk_header_bar_pack_start (GTK_HEADER_BAR (titlebar), edit_toggle);
+      gtk_header_bar_pack_start (GTK_HEADER_BAR (titlebar), reset_button);
+      gtk_header_bar_pack_start (GTK_HEADER_BAR (titlebar), stroke_button);
+
+      gtk_window_set_titlebar (GTK_WINDOW (window), titlebar);
+
+      demo = curve_editor_new ();
+
+      g_signal_connect (stroke_toggle, "toggled", G_CALLBACK (stroke_toggled), demo);
+      g_signal_connect (edit_toggle, "notify::active", G_CALLBACK (edit_changed), demo);
+      g_signal_connect (reset_button, "clicked", G_CALLBACK (reset), demo);
+      g_signal_connect (cap_combo, "notify::selected", G_CALLBACK (cap_changed), demo);
+      g_signal_connect (join_combo, "notify::selected", G_CALLBACK (join_changed), demo);
+      g_signal_connect (color_button, "notify::rgba", G_CALLBACK (color_changed), demo);
+      g_signal_connect (line_width_spin, "value-changed", G_CALLBACK (line_width_changed), demo);
+      g_signal_connect (limit_spin, "value-changed", G_CALLBACK (limit_changed), demo);
+      g_signal_connect (dash_entry, "notify::text", G_CALLBACK (dashes_changed), demo);
+
+      reset (NULL, CURVE_EDITOR (demo));
+
+      gtk_spin_button_set_value (GTK_SPIN_BUTTON (line_width_spin), 6);
+      gtk_color_chooser_set_rgba (GTK_COLOR_CHOOSER (color_button), &(GdkRGBA) { 1, 0, 0, 1 });
+      gtk_drop_down_set_selected (GTK_DROP_DOWN (cap_combo), GSK_LINE_CAP_ROUND);
+      gtk_editable_set_text (GTK_EDITABLE (dash_entry), "0 8");
+
+      gtk_window_set_child (GTK_WINDOW (window), demo);
+    }
+
+  if (!gtk_widget_get_visible (window))
+    gtk_widget_show (window);
+  else
+    gtk_window_destroy (GTK_WINDOW (window));
+
+  return window;
+}

demos/gtk-demo/demo.gresource.xml

@@ -249,6 +249,10 @@
   <gresource prefix="/video-player">
     <file>bbb.png</file>
   </gresource>
+  <gresource prefix="/curve">
+    <file>curve-editor.c</file>
+    <file>curve-editor.h</file>
+  </gresource>
   <gresource prefix="/sources">
     <file>application_demo.c</file>
     <file>assistant.c</file>
@@ -266,6 +270,7 @@
     <file>css_pixbufs.c</file>
     <file>css_shadows.c</file>
     <file>cursors.c</file>
+    <file>curve.c</file>
     <file>dialog.c</file>
     <file>drawingarea.c</file>
     <file>dropdown.c</file>
@@ -286,6 +291,7 @@
     <file>gears.c</file>
     <file>gestures.c</file>
     <file>glarea.c</file>
+    <file>glyphs.c</file>
     <file>gltransition.c</file>
     <file>headerbar.c</file>
     <file>hypertext.c</file>
@@ -324,6 +330,9 @@
     <file>paintable_symbolic.c</file>
     <file>panes.c</file>
     <file>password_entry.c</file>
+    <file>path_fill.c</file>
+    <file>path_maze.c</file>
+    <file>path_text.c</file>
     <file>peg_solitaire.c</file>
     <file>pickers.c</file>
     <file>printing.c</file>
@@ -408,6 +417,9 @@
   <gresource prefix="/fontrendering">
     <file>fontrendering.ui</file>
   </gresource>
+  <gresource prefix="/path_text">
+    <file>path_text.ui</file>
+  </gresource>
   <gresource prefix="/org/gtk/Demo4">
     <file>icons/16x16/actions/application-exit.png</file>
     <file>icons/16x16/actions/document-new.png</file>

demos/gtk-demo/meson.build

@@ -17,6 +17,7 @@ demos = files([
   'css_pixbufs.c',
   'css_shadows.c',
   'cursors.c',
+  'curve.c',
   'dialog.c',
   'drawingarea.c',
   'dnd.c',
@@ -34,6 +35,7 @@ demos = files([
   'gestures.c',
   'glarea.c',
   'gltransition.c',
+  'glyphs.c',
   'headerbar.c',
   'hypertext.c',
   'iconscroll.c',
@@ -70,6 +72,9 @@ demos = files([
   'paintable_symbolic.c',
   'panes.c',
   'password_entry.c',
+  'path_fill.c',
+  'path_maze.c',
+  'path_text.c',
   'peg_solitaire.c',
   'pickers.c',
   'printing.c',
@@ -128,6 +133,7 @@ extra_demo_sources = files([
   'script-names.c',
   'unicode-names.c',
   'suggestionentry.c',
+  'curve-editor.c',
 ])
 
 if harfbuzz_dep.found() and pangoft_dep.found()

demos/gtk-demo/path_fill.c

@@ -0,0 +1,348 @@
+/* Path/Text Fill
+ *
+ * This demo shows how to use PangoCairo to draw text with more than
+ * just a single color.
+ */
+
+#include <glib/gi18n.h>
+#include <gtk/gtk.h>
+
+#include "paintable.h"
+#include "gsk/gskpathdashprivate.h"
+
+#define GTK_TYPE_PATH_PAINTABLE (gtk_path_paintable_get_type ())
+G_DECLARE_FINAL_TYPE (GtkPathPaintable, gtk_path_paintable, GTK, PATH_PAINTABLE, GObject)
+
+struct _GtkPathPaintable
+{
+  GObject parent_instance;
+
+  int width;
+  int height;
+  GskPath *path;
+  GdkPaintable *background;
+};
+
+struct _GtkPathPaintableClass
+{
+  GObjectClass parent_class;
+};
+
+static int
+gtk_path_paintable_get_intrinsic_width (GdkPaintable *paintable)
+{
+  GtkPathPaintable *self = GTK_PATH_PAINTABLE (paintable);
+
+  if (self->background)
+    return MAX (gdk_paintable_get_intrinsic_width (self->background), self->width);
+  else
+    return self->width;
+}
+
+static int
+gtk_path_paintable_get_intrinsic_height (GdkPaintable *paintable)
+{
+  GtkPathPaintable *self = GTK_PATH_PAINTABLE (paintable);
+
+  if (self->background)
+    return MAX (gdk_paintable_get_intrinsic_height (self->background), self->height);
+  else
+    return self->height;
+}
+
+static void
+gtk_path_paintable_snapshot (GdkPaintable *paintable,
+                             GdkSnapshot  *snapshot,
+                             double        width,
+                             double        height)
+{
+  GtkPathPaintable *self = GTK_PATH_PAINTABLE (paintable);
+
+#if 0
+  gtk_snapshot_push_fill (snapshot, self->path, GSK_FILL_RULE_WINDING);
+#else
+  GskStroke *stroke = gsk_stroke_new (2.0);
+  gtk_snapshot_push_stroke (snapshot, self->path, stroke);
+  gsk_stroke_free (stroke);
+#endif
+
+  if (self->background)
+    {
+      gdk_paintable_snapshot (self->background, snapshot, width, height);
+    }
+  else
+    {
+      gtk_snapshot_append_linear_gradient (snapshot,
+                                           &GRAPHENE_RECT_INIT (0, 0, width, height),
+                                           &GRAPHENE_POINT_INIT (0, 0),
+                                           &GRAPHENE_POINT_INIT (width, height),
+                                           (GskColorStop[8]) {
+                                             { 0.0, { 1.0, 0.0, 0.0, 1.0 } },
+                                             { 0.2, { 1.0, 0.0, 0.0, 1.0 } },
+                                             { 0.3, { 1.0, 1.0, 0.0, 1.0 } },
+                                             { 0.4, { 0.0, 1.0, 0.0, 1.0 } },
+                                             { 0.6, { 0.0, 1.0, 1.0, 1.0 } },
+                                             { 0.7, { 0.0, 0.0, 1.0, 1.0 } },
+                                             { 0.8, { 1.0, 0.0, 1.0, 1.0 } },
+                                             { 1.0, { 1.0, 0.0, 1.0, 1.0 } }
+                                           },
+                                           8);
+    }
+
+  gtk_snapshot_pop (snapshot);
+
+}
+
+static GdkPaintableFlags
+gtk_path_paintable_get_flags (GdkPaintable *paintable)
+{
+  GtkPathPaintable *self = GTK_PATH_PAINTABLE (paintable);
+
+  if (self->background)
+    return gdk_paintable_get_flags (self->background);
+  else
+    return GDK_PAINTABLE_STATIC_CONTENTS | GDK_PAINTABLE_STATIC_SIZE;
+}
+
+static void
+gtk_path_paintable_paintable_init (GdkPaintableInterface *iface)
+{
+  iface->get_intrinsic_width = gtk_path_paintable_get_intrinsic_width;
+  iface->get_intrinsic_height = gtk_path_paintable_get_intrinsic_height;
+  iface->snapshot = gtk_path_paintable_snapshot;
+  iface->get_flags = gtk_path_paintable_get_flags;
+}
+
+/* When defining the GType, we need to implement the GdkPaintable interface */
+G_DEFINE_TYPE_WITH_CODE (GtkPathPaintable, gtk_path_paintable, G_TYPE_OBJECT,
+                         G_IMPLEMENT_INTERFACE (GDK_TYPE_PAINTABLE,
+                                                gtk_path_paintable_paintable_init))
+
+/* Here's the boilerplate for the GObject declaration.
+ * We don't need to do anything special here, because we keep no
+ * data of our own.
+ */
+static void
+gtk_path_paintable_class_init (GtkPathPaintableClass *klass)
+{
+}
+
+static void
+gtk_path_paintable_init (GtkPathPaintable *self)
+{
+}
+
+/* And finally, we add a simple constructor.
+ * It is declared in the header so that the other examples
+ * can use it.
+ */
+GdkPaintable *
+gtk_path_paintable_new (GskPath      *path,
+                        GdkPaintable *background,
+                        int           width,
+                        int           height)
+{
+  GtkPathPaintable *self;
+
+  self = g_object_new (GTK_TYPE_PATH_PAINTABLE, NULL);
+  self->path = path;
+  self->background = background;
+  if (self->background)
+    {
+      g_signal_connect_swapped (self->background, "invalidate-contents", G_CALLBACK (gdk_paintable_invalidate_contents), self);
+      g_signal_connect_swapped (self->background, "invalidate-size", G_CALLBACK (gdk_paintable_invalidate_size), self);
+    }
+  self->width = width;
+  self->height = height;
+
+  return GDK_PAINTABLE (self);
+}
+
+void
+gtk_path_paintable_set_path (GtkPathPaintable *self,
+                             GskPath          *path)
+{
+  g_clear_pointer (&self->path, gsk_path_unref);
+  self->path = gsk_path_ref (path);
+
+  gdk_paintable_invalidate_contents (GDK_PAINTABLE (self));
+}
+
+static GskPath *
+create_hexagon (GtkWidget *widget)
+{
+  GskPathBuilder *builder;
+
+  builder = gsk_path_builder_new ();
+
+  gsk_path_builder_move_to (builder, 120, 0);
+  gsk_path_builder_line_to (builder, 360, 0);
+  gsk_path_builder_line_to (builder, 480, 208);
+  gsk_path_builder_line_to (builder, 360, 416);
+  gsk_path_builder_line_to (builder, 120, 416);
+  gsk_path_builder_line_to (builder, 0, 208);
+  gsk_path_builder_close (builder);
+
+  return gsk_path_builder_free_to_path (builder);
+}
+
+static GskPath *
+create_path_from_text (GtkWidget *widget)
+{
+  PangoLayout *layout;
+  PangoFontDescription *desc;
+  GskPathBuilder *builder;
+
+  layout = gtk_widget_create_pango_layout (widget, "Pango power!\nPango power!\nPango power!");
+  desc = pango_font_description_from_string ("sans bold 36");
+  pango_layout_set_font_description (layout, desc);
+  pango_font_description_free (desc);
+
+  builder = gsk_path_builder_new ();
+
+  gsk_path_builder_add_layout (builder, layout);
+
+  return gsk_path_builder_free_to_path (builder);
+}
+
+static gboolean
+build_path (GskPathOperation        op,
+            const graphene_point_t *pts,
+            gsize                   n_pts,
+            float                   weight,
+            gpointer                user_data)
+{
+  GskPathBuilder *builder = user_data;
+
+  switch (op)
+  {
+    case GSK_PATH_MOVE:
+      gsk_path_builder_move_to (builder, pts[0].x, pts[0].y);
+      break;
+
+    case GSK_PATH_CLOSE:
+      gsk_path_builder_close (builder);
+      break;
+
+    case GSK_PATH_LINE:
+      gsk_path_builder_line_to (builder, pts[1].x, pts[1].y);
+      break;
+
+    case GSK_PATH_CURVE:
+      gsk_path_builder_curve_to (builder, pts[1].x, pts[1].y, pts[2].x, pts[2].y, pts[3].x, pts[3].y);
+      break;
+
+    case GSK_PATH_CONIC:
+      gsk_path_builder_conic_to (builder, pts[1].x, pts[1].y, pts[2].x, pts[2].y, weight);
+      break;
+
+    default:
+      g_assert_not_reached ();
+      break;
+  }
+
+  return TRUE;
+}
+
+
+static gboolean
+update_path (GtkWidget     *widget,
+             GdkFrameClock *frame_clock,
+             gpointer       measure)
+{
+  float progress = gdk_frame_clock_get_frame_time (frame_clock) % (60 * G_USEC_PER_SEC) / (float) (30 * G_USEC_PER_SEC);
+  GskPathBuilder *builder;
+  GskPath *path;
+  graphene_point_t pos;
+  graphene_vec2_t tangent;
+  GskStroke *stroke;
+
+  builder = gsk_path_builder_new ();
+  gsk_path_builder_add_segment (builder,
+                                measure,
+#if 1
+                                0.0, gsk_path_measure_get_length (measure));
+#else
+                                progress > 1 ? (progress - 1) * gsk_path_measure_get_length (measure) : 0.0,
+                                (progress < 1 ? progress : 1.0) * gsk_path_measure_get_length (measure));
+#endif
+
+  path = gsk_path_builder_free_to_path (builder);
+
+  stroke = gsk_stroke_new (1);
+  gsk_stroke_set_dash (stroke, (float[2]) { 10, 5 }, 2);
+  gsk_stroke_set_dash_offset (stroke, - (gdk_frame_clock_get_frame_time (frame_clock) % G_USEC_PER_SEC) * 15. / G_USEC_PER_SEC);
+  builder = gsk_path_builder_new ();
+  gsk_path_dash (path, stroke, 0.2, build_path, builder);
+  gsk_path_unref (path);
+
+  gsk_path_measure_get_point (measure,
+                              (progress > 1 ? (progress - 1) : progress) * gsk_path_measure_get_length (measure),
+                              &pos,
+                              &tangent);
+  gsk_path_builder_move_to (builder, pos.x + 5 * graphene_vec2_get_x (&tangent), pos.y + 5 * graphene_vec2_get_y (&tangent));
+  gsk_path_builder_line_to (builder, pos.x + 3 * graphene_vec2_get_y (&tangent), pos.y + 3 * graphene_vec2_get_x (&tangent));
+  gsk_path_builder_line_to (builder, pos.x - 3 * graphene_vec2_get_y (&tangent), pos.y - 3 * graphene_vec2_get_x (&tangent));
+  gsk_path_builder_close (builder);
+
+  path = gsk_path_builder_free_to_path (builder);
+
+  gtk_path_paintable_set_path (GTK_PATH_PAINTABLE (gtk_picture_get_paintable (GTK_PICTURE (widget))),
+                               path);
+  gsk_path_unref (path);
+
+  return G_SOURCE_CONTINUE;
+}
+
+GtkWidget *
+do_path_fill (GtkWidget *do_widget)
+{
+  static GtkWidget *window = NULL;
+
+  if (!window)
+    {
+      GtkWidget *picture;
+      GdkPaintable *paintable;
+      GtkMediaStream *stream;
+      GskPath *path;
+      graphene_rect_t bounds;
+      GskPathMeasure *measure;
+
+      window = gtk_window_new ();
+      gtk_window_set_resizable (GTK_WINDOW (window), TRUE);
+      gtk_window_set_title (GTK_WINDOW (window), "Path Fill");
+      g_object_add_weak_pointer (G_OBJECT (window), (gpointer *)&window);
+
+#if 0
+      stream = gtk_media_file_new_for_resource ("/images/gtk-logo.webm");
+#else
+      stream = gtk_nuclear_media_stream_new ();
+#endif
+      gtk_media_stream_play (stream);
+      gtk_media_stream_set_loop (stream, TRUE);
+
+      path = create_hexagon (window);
+      path = create_path_from_text (window);
+      gsk_path_get_bounds (path, &bounds);
+
+      paintable = gtk_path_paintable_new (path,
+                                          GDK_PAINTABLE (stream),
+                                          bounds.origin.x + bounds.size.width,
+                                          bounds.origin.y + bounds.size.height);
+      picture = gtk_picture_new_for_paintable (paintable);
+      measure = gsk_path_measure_new (path);
+      gtk_widget_add_tick_callback (picture, update_path, measure, (GDestroyNotify) gsk_path_measure_unref);
+      gtk_picture_set_keep_aspect_ratio (GTK_PICTURE (picture), FALSE);
+      gtk_picture_set_can_shrink (GTK_PICTURE (picture), FALSE);
+      g_object_unref (paintable);
+
+      gtk_window_set_child (GTK_WINDOW (window), picture);
+    }
+
+  if (!gtk_widget_get_visible (window))
+    gtk_widget_show (window);
+  else
+    gtk_window_destroy (GTK_WINDOW (window));
+
+  return window;
+}

demos/gtk-demo/path_maze.c

@@ -0,0 +1,339 @@
+/* Path/Maze
+ * #Keywords: game, mouse
+ *
+ * This demo shows how to use a GskPath to create a maze and use
+ * gsk_path_measure_get_closest_point() to check the mouse stays
+ * on the path.
+ *
+ * It also shows off the performance of GskPath (or not) as this
+ * is a rather complex path.
+ */
+
+#include <glib/gi18n.h>
+#include <gtk/gtk.h>
+
+#include "paintable.h"
+
+#define MAZE_GRID_SIZE 20
+#define MAZE_STROKE_SIZE_ACTIVE (MAZE_GRID_SIZE - 4)
+#define MAZE_STROKE_SIZE_INACTIVE (MAZE_GRID_SIZE - 12)
+#define MAZE_WIDTH 31
+#define MAZE_HEIGHT 21
+
+#define GTK_TYPE_MAZE (gtk_maze_get_type ())
+G_DECLARE_FINAL_TYPE (GtkMaze, gtk_maze, GTK, MAZE, GtkWidget)
+
+struct _GtkMaze
+{
+  GtkWidget parent_instance;
+
+  int width;
+  int height;
+  GskPath *path;
+  GskPathMeasure *measure;
+  GdkPaintable *background;
+
+  gboolean active;
+};
+
+struct _GtkMazeClass
+{
+  GtkWidgetClass parent_class;
+};
+
+G_DEFINE_TYPE (GtkMaze, gtk_maze, GTK_TYPE_WIDGET)
+
+static void
+gtk_maze_measure (GtkWidget      *widget,
+                  GtkOrientation  orientation,
+                  int             for_size,
+                  int            *minimum,
+                  int            *natural,
+                  int            *minimum_baseline,
+                  int            *natural_baseline)
+{
+  GtkMaze *self = GTK_MAZE (widget);
+
+  if (orientation == GTK_ORIENTATION_HORIZONTAL)
+    *minimum = *natural = self->width;
+  else
+    *minimum = *natural = self->height;
+}
+
+static void
+gtk_maze_snapshot (GtkWidget   *widget,
+                   GdkSnapshot *snapshot)
+{
+  GtkMaze *self = GTK_MAZE (widget);
+  double width = gtk_widget_get_width (widget);
+  double height = gtk_widget_get_height (widget);
+  GskStroke *stroke;
+
+  stroke = gsk_stroke_new (MAZE_STROKE_SIZE_INACTIVE);
+  if (self->active)
+    gsk_stroke_set_line_width (stroke, MAZE_STROKE_SIZE_ACTIVE);
+  gsk_stroke_set_line_join (stroke, GSK_LINE_JOIN_ROUND);
+  gsk_stroke_set_line_cap (stroke, GSK_LINE_CAP_ROUND);
+  gtk_snapshot_push_stroke (snapshot, self->path, stroke);
+  gsk_stroke_free (stroke);
+
+  if (self->background)
+    {
+      gdk_paintable_snapshot (self->background, snapshot, width, height);
+    }
+  else
+    {
+      gtk_snapshot_append_linear_gradient (snapshot,
+                                           &GRAPHENE_RECT_INIT (0, 0, width, height),
+                                           &GRAPHENE_POINT_INIT (0, 0),
+                                           &GRAPHENE_POINT_INIT (width, height),
+                                           (GskColorStop[8]) {
+                                             { 0.0, { 1.0, 0.0, 0.0, 1.0 } },
+                                             { 0.2, { 1.0, 0.0, 0.0, 1.0 } },
+                                             { 0.3, { 1.0, 1.0, 0.0, 1.0 } },
+                                             { 0.4, { 0.0, 1.0, 0.0, 1.0 } },
+                                             { 0.6, { 0.0, 1.0, 1.0, 1.0 } },
+                                             { 0.7, { 0.0, 0.0, 1.0, 1.0 } },
+                                             { 0.8, { 1.0, 0.0, 1.0, 1.0 } },
+                                             { 1.0, { 1.0, 0.0, 1.0, 1.0 } }
+                                           },
+                                           8);
+    }
+
+  gtk_snapshot_pop (snapshot);
+
+}
+
+static void
+gtk_maze_dispose (GObject *object)
+{
+  GtkMaze *self = GTK_MAZE (object);
+
+  g_clear_pointer (&self->path, gsk_path_unref);
+  g_clear_pointer (&self->measure, gsk_path_measure_unref);
+  if (self->background)
+    {
+      g_signal_handlers_disconnect_matched (self->background, G_SIGNAL_MATCH_DATA, 0, 0, NULL, NULL, self);
+      g_clear_object (&self->background);
+    }
+
+  G_OBJECT_CLASS (gtk_maze_parent_class)->dispose (object);
+}
+
+static void
+gtk_maze_class_init (GtkMazeClass *klass)
+{
+  GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  object_class->dispose = gtk_maze_dispose;
+
+  widget_class->measure = gtk_maze_measure;
+  widget_class->snapshot = gtk_maze_snapshot;
+}
+
+static void
+pointer_motion (GtkEventControllerMotion *controller,
+                double                    x,
+                double                    y,
+                GtkMaze                  *self)
+{
+  if (!self->active)
+    return;
+
+  if (gsk_path_measure_get_closest_point (self->measure, &GRAPHENE_POINT_INIT (x, y), NULL) <= MAZE_STROKE_SIZE_ACTIVE / 2.0f)
+    return;
+
+  self->active = FALSE;
+  gtk_widget_queue_draw (GTK_WIDGET (self));
+}
+
+static void
+pointer_leave (GtkEventControllerMotion *controller,
+               GtkMaze                  *self)
+{
+  if (!self->active)
+    {
+      self->active = TRUE;
+      gtk_widget_queue_draw (GTK_WIDGET (self));
+    }
+}
+
+static void
+gtk_maze_init (GtkMaze *self)
+{
+  GtkEventController *controller;
+
+  controller = GTK_EVENT_CONTROLLER (gtk_event_controller_motion_new ());
+  g_signal_connect (controller, "motion", G_CALLBACK (pointer_motion), self);
+  g_signal_connect (controller, "leave", G_CALLBACK (pointer_leave), self);
+  gtk_widget_add_controller (GTK_WIDGET (self), controller);
+
+  self->active = TRUE;
+}
+
+static void
+gtk_maze_set_path (GtkMaze *self,
+                   GskPath *path)
+{
+  g_clear_pointer (&self->path, gsk_path_unref);
+  g_clear_pointer (&self->measure, gsk_path_measure_unref);
+  self->path = gsk_path_ref (path);
+  self->measure = gsk_path_measure_new (path);
+
+  gtk_widget_queue_draw (GTK_WIDGET (self));
+}
+
+GtkWidget *
+gtk_maze_new (GskPath      *path,
+              GdkPaintable *background,
+              int           width,
+              int           height)
+{
+  GtkMaze *self;
+
+  self = g_object_new (GTK_TYPE_MAZE, NULL);
+
+  gtk_maze_set_path (self, path);
+  gsk_path_unref (path);
+  self->background = background;
+  if (self->background)
+    {
+      g_signal_connect_swapped (self->background, "invalidate-contents", G_CALLBACK (gtk_widget_queue_draw), self);
+      g_signal_connect_swapped (self->background, "invalidate-size", G_CALLBACK (gtk_widget_queue_resize), self);
+    }
+  self->width = width;
+  self->height = height;
+
+  return GTK_WIDGET (self);
+}
+
+static void
+add_point_to_maze (GtkBitset      *maze,
+                   GskPathBuilder *builder,
+                   guint           x,
+                   guint           y)
+{
+  gboolean set[4] = { };
+  guint dir;
+
+  gtk_bitset_add (maze, y * MAZE_WIDTH + x);
+
+  while (TRUE)
+    {
+      set[0] = set[0] || x == 0 || gtk_bitset_contains (maze, y * MAZE_WIDTH + x - 1);
+      set[1] = set[1] || y == 0 || gtk_bitset_contains (maze, (y - 1) * MAZE_WIDTH + x);
+      set[2] = set[2] || x + 1 == MAZE_WIDTH || gtk_bitset_contains (maze, y * MAZE_WIDTH + x + 1);
+      set[3] = set[3] || y + 1 == MAZE_HEIGHT || gtk_bitset_contains (maze, (y + 1) * MAZE_WIDTH + x);
+
+      if (set[0] && set[1] && set[2] && set[3])
+        return;
+
+      do
+        {
+          dir = g_random_int_range (0, 4);
+        }
+      while (set[dir]);
+
+      switch (dir)
+        {
+          case 0:
+            gsk_path_builder_move_to (builder, (x + 0.5) * MAZE_GRID_SIZE, (y + 0.5) * MAZE_GRID_SIZE);
+            gsk_path_builder_line_to (builder, (x - 0.5) * MAZE_GRID_SIZE, (y + 0.5) * MAZE_GRID_SIZE);
+            add_point_to_maze (maze, builder, x - 1, y);
+            break;
+
+          case 1:
+            gsk_path_builder_move_to (builder, (x + 0.5) * MAZE_GRID_SIZE, (y + 0.5) * MAZE_GRID_SIZE);
+            gsk_path_builder_line_to (builder, (x + 0.5) * MAZE_GRID_SIZE, (y - 0.5) * MAZE_GRID_SIZE);
+            add_point_to_maze (maze, builder, x, y - 1);
+            break;
+
+          case 2:
+            gsk_path_builder_move_to (builder, (x + 0.5) * MAZE_GRID_SIZE, (y + 0.5) * MAZE_GRID_SIZE);
+            gsk_path_builder_line_to (builder, (x + 1.5) * MAZE_GRID_SIZE, (y + 0.5) * MAZE_GRID_SIZE);
+            add_point_to_maze (maze, builder, x + 1, y);
+            break;
+
+          case 3:
+            gsk_path_builder_move_to (builder, (x + 0.5) * MAZE_GRID_SIZE, (y + 0.5) * MAZE_GRID_SIZE);
+            gsk_path_builder_line_to (builder, (x + 0.5) * MAZE_GRID_SIZE, (y + 1.5) * MAZE_GRID_SIZE);
+            add_point_to_maze (maze, builder, x, y + 1);
+            break;
+
+          default:
+            g_assert_not_reached ();
+            break;
+        }
+    }
+}
+
+static GskPath *
+create_path_for_maze (GtkWidget *widget)
+{
+  GskPathBuilder *builder;
+  GtkBitset *maze;
+
+  builder = gsk_path_builder_new ();
+  maze = gtk_bitset_new_empty ();
+  /* make sure the outer lines are unreachable:
+   * Set the full range, then remove the center again. */
+  gtk_bitset_add_range (maze, 0, MAZE_WIDTH * MAZE_HEIGHT);
+  gtk_bitset_remove_rectangle (maze, MAZE_WIDTH + 1, MAZE_WIDTH - 2, MAZE_HEIGHT - 2, MAZE_WIDTH);
+
+  /* Fill the maze */
+  add_point_to_maze (maze, builder, MAZE_WIDTH / 2, MAZE_HEIGHT / 2);
+
+  /* Add start and stop lines */
+  gsk_path_builder_move_to (builder, 1.5 * MAZE_GRID_SIZE, -0.5 * MAZE_GRID_SIZE);
+  gsk_path_builder_line_to (builder, 1.5 * MAZE_GRID_SIZE, 1.5 * MAZE_GRID_SIZE);
+  gsk_path_builder_move_to (builder, (MAZE_WIDTH - 1.5) * MAZE_GRID_SIZE, (MAZE_HEIGHT - 1.5) * MAZE_GRID_SIZE);
+  gsk_path_builder_line_to (builder, (MAZE_WIDTH - 1.5) * MAZE_GRID_SIZE, (MAZE_HEIGHT + 0.5) * MAZE_GRID_SIZE);
+
+
+  gtk_bitset_unref (maze);
+
+  return gsk_path_builder_free_to_path (builder);
+}
+
+GtkWidget *
+do_path_maze (GtkWidget *do_widget)
+{
+  static GtkWidget *window = NULL;
+
+  if (!window)
+    {
+      GtkWidget *maze;
+      GtkMediaStream *stream;
+      GskPath *path;
+
+      window = gtk_window_new ();
+      gtk_window_set_resizable (GTK_WINDOW (window), TRUE);
+      gtk_window_set_title (GTK_WINDOW (window), "Follow the maze with the mouse");
+      g_object_add_weak_pointer (G_OBJECT (window), (gpointer *)&window);
+
+#if 0
+      stream = gtk_media_file_new_for_resource ("/images/gtk-logo.webm");
+#else
+      stream = gtk_nuclear_media_stream_new ();
+#endif
+      gtk_media_stream_play (stream);
+      gtk_media_stream_set_loop (stream, TRUE);
+
+      path = create_path_for_maze (window);
+
+      maze = gtk_maze_new (path,
+                           GDK_PAINTABLE (stream),
+                           MAZE_WIDTH * MAZE_GRID_SIZE,
+                           MAZE_HEIGHT * MAZE_GRID_SIZE);
+
+      gtk_window_set_child (GTK_WINDOW (window), maze);
+    }
+
+  if (!gtk_widget_get_visible (window))
+    gtk_widget_show (window);
+  else
+    gtk_window_destroy (GTK_WINDOW (window));
+
+  return window;
+}

demos/gtk-demo/path_text.c

@@ -0,0 +1,594 @@
+/* Path/Curved Text
+ *
+ * This demo shows how to use GskPath to animate a path along another path.
+ */
+
+#include <glib/gi18n.h>
+#include <gtk/gtk.h>
+
+#define GTK_TYPE_PATH_WIDGET (gtk_path_widget_get_type ())
+G_DECLARE_FINAL_TYPE (GtkPathWidget, gtk_path_widget, GTK, PATH_WIDGET, GtkWidget)
+
+#define POINT_SIZE 8
+
+enum {
+  PROP_0,
+  PROP_TEXT,
+  PROP_EDITABLE,
+  N_PROPS
+};
+
+struct _GtkPathWidget
+{
+  GtkWidget parent_instance;
+
+  char *text;
+  gboolean editable;
+
+  graphene_point_t points[4];
+
+  guint active_point;
+  float line_closest;
+
+  GskPath *line_path;
+  GskPathMeasure *line_measure;
+  GskPath *text_path;
+
+  GdkPaintable *background;
+};
+
+struct _GtkPathWidgetClass
+{
+  GtkWidgetClass parent_class;
+};
+
+static GParamSpec *properties[N_PROPS] = { NULL, };
+
+G_DEFINE_TYPE (GtkPathWidget, gtk_path_widget, GTK_TYPE_WIDGET)
+
+static GskPath *
+create_path_from_text (GtkWidget  *widget,
+                       const char *text)
+{
+  cairo_surface_t *surface;
+  cairo_t *cr;
+  cairo_path_t *path;
+  PangoLayout *layout;
+  PangoFontDescription *desc;
+  GskPath *result;
+
+  surface = cairo_recording_surface_create (CAIRO_CONTENT_COLOR_ALPHA, NULL);
+  cr = cairo_create (surface);
+
+  layout = gtk_widget_create_pango_layout (widget, text);
+  desc = pango_font_description_from_string ("sans bold 36");
+  pango_layout_set_font_description (layout, desc);
+  pango_font_description_free (desc);
+
+  cairo_move_to (cr, 0, - pango_layout_get_baseline (layout) / (double) PANGO_SCALE);
+  pango_cairo_layout_path (cr, layout);
+  path = cairo_copy_path_flat (cr);
+  result = gsk_path_new_from_cairo (path);
+
+  cairo_path_destroy (path);
+  g_object_unref (layout);
+  cairo_destroy (cr);
+  cairo_surface_destroy (surface);
+
+  return result;
+}
+
+typedef struct
+{
+  GskPathMeasure *measure;
+  GskPathBuilder *builder;
+  double scale;
+} GtkPathTransform;
+
+static void
+gtk_path_transform_point (GskPathMeasure         *measure,
+                          const graphene_point_t *pt,
+                          float                   scale,
+                          graphene_point_t       *res)
+{
+  graphene_vec2_t tangent;
+
+  gsk_path_measure_get_point (measure, pt->x * scale, res, &tangent);
+
+  res->x -= pt->y * scale * graphene_vec2_get_y (&tangent);
+  res->y += pt->y * scale * graphene_vec2_get_x (&tangent);
+}
+
+static gboolean
+gtk_path_transform_op (GskPathOperation        op,
+                       const graphene_point_t *pts,
+                       gsize                   n_pts,
+                       float                   weight,
+                       gpointer                data)
+{
+  GtkPathTransform *transform = data;
+
+  switch (op)
+  {
+    case GSK_PATH_MOVE:
+      {
+        graphene_point_t res;
+        gtk_path_transform_point (transform->measure, &pts[0], transform->scale, &res);
+        gsk_path_builder_move_to (transform->builder, res.x, res.y);
+      }
+      break;
+
+    case GSK_PATH_LINE:
+      {
+        graphene_point_t res;
+        gtk_path_transform_point (transform->measure, &pts[1], transform->scale, &res);
+        gsk_path_builder_line_to (transform->builder, res.x, res.y);
+      }
+      break;
+
+    case GSK_PATH_CURVE:
+      {
+        graphene_point_t res[3];
+        gtk_path_transform_point (transform->measure, &pts[1], transform->scale, &res[0]);
+        gtk_path_transform_point (transform->measure, &pts[2], transform->scale, &res[1]);
+        gtk_path_transform_point (transform->measure, &pts[3], transform->scale, &res[2]);
+        gsk_path_builder_curve_to (transform->builder, res[0].x, res[0].y, res[1].x, res[1].y, res[2].x, res[2].y);
+      }
+      break;
+
+    case GSK_PATH_CONIC:
+      {
+        graphene_point_t res[2];
+        gtk_path_transform_point (transform->measure, &pts[1], transform->scale, &res[0]);
+        gtk_path_transform_point (transform->measure, &pts[2], transform->scale, &res[1]);
+        gsk_path_builder_conic_to (transform->builder, res[0].x, res[0].y, res[1].x, res[1].y, weight);
+      }
+      break;
+
+    case GSK_PATH_CLOSE:
+      gsk_path_builder_close (transform->builder);
+      break;
+
+    default:
+      g_assert_not_reached();
+      return FALSE;
+  }
+
+  return TRUE;
+}
+
+static GskPath *
+gtk_path_transform (GskPathMeasure *measure,
+                    GskPath        *path)
+{
+  GtkPathTransform transform = { measure, gsk_path_builder_new () };
+  graphene_rect_t bounds;
+
+  gsk_path_get_bounds (path, &bounds);
+  if (bounds.origin.x + bounds.size.width > 0)
+    transform.scale = gsk_path_measure_get_length (measure) / (bounds.origin.x + bounds.size.width);
+  else
+    transform.scale = 1.0f;
+
+  gsk_path_foreach (path, GSK_PATH_FOREACH_ALLOW_CURVE, gtk_path_transform_op, &transform);
+
+  return gsk_path_builder_free_to_path (transform.builder);
+}
+
+static void
+gtk_path_widget_clear_text_path (GtkPathWidget *self)
+{
+  g_clear_pointer (&self->text_path, gsk_path_unref);
+}
+
+static void
+gtk_path_widget_clear_paths (GtkPathWidget *self)
+{
+  gtk_path_widget_clear_text_path (self);
+
+  g_clear_pointer (&self->line_path, gsk_path_unref);
+  g_clear_pointer (&self->line_measure, gsk_path_measure_unref);
+}
+
+static void
+gtk_path_widget_create_text_path (GtkPathWidget *self)
+{
+  GskPath *path;
+
+  gtk_path_widget_clear_text_path (self);
+
+  if (self->line_measure == NULL)
+    return;
+
+  path = create_path_from_text (GTK_WIDGET (self), self->text);
+  self->text_path = gtk_path_transform (self->line_measure, path);
+
+  gsk_path_unref (path);
+}
+
+static void
+gtk_path_widget_create_paths (GtkPathWidget *self)
+{
+  double width = gtk_widget_get_width (GTK_WIDGET (self));
+  double height = gtk_widget_get_height (GTK_WIDGET (self));
+  GskPathBuilder *builder;
+
+  gtk_path_widget_clear_paths (self);
+
+  if (width <= 0 || height <= 0)
+    return;
+
+  builder = gsk_path_builder_new ();
+  gsk_path_builder_move_to (builder,
+                            self->points[0].x * width, self->points[0].y * height);
+  gsk_path_builder_curve_to (builder,
+                             self->points[1].x * width, self->points[1].y * height,
+                             self->points[2].x * width, self->points[2].y * height,
+                             self->points[3].x * width, self->points[3].y * height);
+  self->line_path = gsk_path_builder_free_to_path (builder);
+
+  self->line_measure = gsk_path_measure_new (self->line_path);
+
+  gtk_path_widget_create_text_path (self);
+}
+
+static void
+gtk_path_widget_allocate (GtkWidget *widget,
+                          int        width,
+                          int        height,
+                          int        baseline)
+{
+  GtkPathWidget *self = GTK_PATH_WIDGET (widget);
+
+  GTK_WIDGET_CLASS (gtk_path_widget_parent_class)->size_allocate (widget, width, height, baseline);
+
+  gtk_path_widget_create_paths (self);
+}
+
+static void
+gtk_path_widget_snapshot (GtkWidget   *widget,
+                          GtkSnapshot *snapshot)
+{
+  GtkPathWidget *self = GTK_PATH_WIDGET (widget);
+  double width = gtk_widget_get_width (widget);
+  double height = gtk_widget_get_height (widget);
+  GskPath *path;
+  GskStroke *stroke;
+  gsize i;
+
+  /* frosted glass the background */
+  gtk_snapshot_push_blur (snapshot, 100);
+  gdk_paintable_snapshot (self->background, snapshot, width, height);
+  gtk_snapshot_append_color (snapshot, &(GdkRGBA) { 1, 1, 1, 0.5 }, &GRAPHENE_RECT_INIT (0, 0, width, height));
+  gtk_snapshot_pop (snapshot);
+
+  /* draw the text */
+  if (self->text_path)
+    {
+      gtk_snapshot_push_fill (snapshot, self->text_path, GSK_FILL_RULE_WINDING);
+      gdk_paintable_snapshot (self->background, snapshot, width, height);
+
+      /* ... with an emboss effect */
+      stroke = gsk_stroke_new (2.0);
+      gtk_snapshot_translate (snapshot, &GRAPHENE_POINT_INIT(1, 1));
+      gtk_snapshot_push_stroke (snapshot, self->text_path, stroke);
+      gtk_snapshot_append_color (snapshot, &(GdkRGBA) { 0, 0, 0, 0.2 }, &GRAPHENE_RECT_INIT (0, 0, width, height));
+      gsk_stroke_free (stroke);
+      gtk_snapshot_pop (snapshot);
+
+      gtk_snapshot_pop (snapshot);
+    }
+
+  if (self->editable && self->line_path)
+    {
+      /* draw the control line */
+      stroke = gsk_stroke_new (1.0);
+      gtk_snapshot_push_stroke (snapshot, self->line_path, stroke);
+      gsk_stroke_free (stroke);
+      gtk_snapshot_append_color (snapshot, &(GdkRGBA) { 0, 0, 0, 1 }, &GRAPHENE_RECT_INIT (0, 0, width, height));
+      gtk_snapshot_pop (snapshot);
+    }
+
+  if (self->line_closest >= 0)
+    {
+      GskPathBuilder *builder;
+      graphene_point_t closest;
+
+      builder = gsk_path_builder_new ();
+      gsk_path_measure_get_point (self->line_measure, self->line_closest, &closest, NULL);
+      gsk_path_builder_add_circle (builder, &closest, POINT_SIZE);
+      path = gsk_path_builder_free_to_path (builder);
+
+      gtk_snapshot_push_fill (snapshot, path, GSK_FILL_RULE_WINDING);
+      gtk_snapshot_append_color (snapshot, &(GdkRGBA) { 0, 0, 1, 1 }, &GRAPHENE_RECT_INIT (0, 0, width, height));
+      gtk_snapshot_pop (snapshot);
+
+      gsk_path_unref (path);
+    }
+
+  if (self->editable && self->line_path)
+    {
+      GskPathBuilder *builder;
+
+      /* draw the points */
+      builder = gsk_path_builder_new ();
+      for (i = 0; i < 4; i++)
+        {
+          gsk_path_builder_add_circle (builder, &GRAPHENE_POINT_INIT (self->points[i].x * width, self->points[i].y * height), POINT_SIZE);
+        }
+      path = gsk_path_builder_free_to_path (builder);
+
+      gtk_snapshot_push_fill (snapshot, path, GSK_FILL_RULE_WINDING);
+      gtk_snapshot_append_color (snapshot, &(GdkRGBA) { 1, 1, 1, 1 }, &GRAPHENE_RECT_INIT (0, 0, width, height));
+      gtk_snapshot_pop (snapshot);
+
+      stroke = gsk_stroke_new (1.0);
+      gtk_snapshot_push_stroke (snapshot, path, stroke);
+      gsk_stroke_free (stroke);
+      gtk_snapshot_append_color (snapshot, &(GdkRGBA) { 0, 0, 0, 1 }, &GRAPHENE_RECT_INIT (0, 0, width, height));
+      gtk_snapshot_pop (snapshot);
+
+      gsk_path_unref (path);
+    }
+}
+
+static void
+gtk_path_widget_set_text (GtkPathWidget *self,
+                          const char    *text)
+{
+  if (g_strcmp0 (self->text, text) == 0)
+    return;
+
+  g_free (self->text);
+  self->text = g_strdup (text);
+
+  gtk_path_widget_create_paths (self);
+
+  gtk_widget_queue_draw (GTK_WIDGET (self));
+
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_TEXT]);
+}
+
+static void
+gtk_path_widget_set_editable (GtkPathWidget *self,
+                              gboolean       editable)
+{
+  if (self->editable == editable)
+    return;
+
+  self->editable = editable;
+
+  gtk_widget_queue_draw (GTK_WIDGET (self));
+
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_EDITABLE]);
+}
+
+static void
+gtk_path_widget_set_property (GObject      *object,
+                              guint         prop_id,
+                              const GValue *value,
+                              GParamSpec   *pspec)
+
+{
+  GtkPathWidget *self = GTK_PATH_WIDGET (object);
+
+  switch (prop_id)
+    {
+    case PROP_TEXT:
+      gtk_path_widget_set_text (self, g_value_get_string (value));
+      break;
+
+    case PROP_EDITABLE:
+      gtk_path_widget_set_editable (self, g_value_get_boolean (value));
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void
+gtk_path_widget_get_property (GObject    *object,
+                              guint       prop_id,
+                              GValue     *value,
+                              GParamSpec *pspec)
+{
+  GtkPathWidget *self = GTK_PATH_WIDGET (object);
+
+  switch (prop_id)
+    {
+    case PROP_TEXT:
+      g_value_set_string (value, self->text);
+      break;
+
+    case PROP_EDITABLE:
+      g_value_set_boolean (value, self->editable);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void
+gtk_path_widget_dispose (GObject *object)
+{
+  GtkPathWidget *self = GTK_PATH_WIDGET (object);
+
+  gtk_path_widget_clear_paths (self);
+
+  G_OBJECT_CLASS (gtk_path_widget_parent_class)->dispose (object);
+}
+
+static void
+gtk_path_widget_class_init (GtkPathWidgetClass *klass)
+{
+  GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  object_class->dispose = gtk_path_widget_dispose;
+  object_class->set_property = gtk_path_widget_set_property;
+  object_class->get_property = gtk_path_widget_get_property;
+
+  widget_class->size_allocate = gtk_path_widget_allocate;
+  widget_class->snapshot = gtk_path_widget_snapshot;
+
+  properties[PROP_TEXT] =
+    g_param_spec_string ("text",
+                         "text",
+                         "Text transformed along a path",
+                         NULL,
+                         G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
+  properties[PROP_EDITABLE] =
+    g_param_spec_boolean ("editable",
+                          "editable",
+                          "If the path can be edited by the user",
+                          FALSE,
+                          G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
+  g_object_class_install_properties (object_class, N_PROPS, properties);
+}
+
+static void
+drag_begin (GtkGestureDrag *gesture,
+            double          x,
+            double          y,
+            GtkPathWidget  *self)
+{
+  graphene_point_t mouse = GRAPHENE_POINT_INIT (x, y);
+  double width = gtk_widget_get_width (GTK_WIDGET (self));
+  double height = gtk_widget_get_height (GTK_WIDGET (self));
+  gsize i;
+
+  for (i = 0; i < 4; i++)
+    {
+      if (graphene_point_distance (&GRAPHENE_POINT_INIT (self->points[i].x * width, self->points[i].y * height), &mouse, NULL, NULL) <= POINT_SIZE)
+        {
+          self->active_point = i;
+          break;
+        }
+    }
+  if (i == 4)
+    {
+      gtk_gesture_set_state (GTK_GESTURE (gesture), GTK_EVENT_SEQUENCE_DENIED);
+      return;
+    }
+
+  gtk_widget_queue_draw (GTK_WIDGET (self));
+}
+
+static void
+drag_update (GtkGestureDrag *drag,
+             double          offset_x,
+             double          offset_y,
+             GtkPathWidget  *self)
+{
+  double width = gtk_widget_get_width (GTK_WIDGET (self));
+  double height = gtk_widget_get_height (GTK_WIDGET (self));
+  double start_x, start_y;
+
+  gtk_gesture_drag_get_start_point (drag, &start_x, &start_y);
+
+  self->points[self->active_point] = GRAPHENE_POINT_INIT ((start_x + offset_x) / width,
+                                                          (start_y + offset_y) / height);
+  self->points[self->active_point].x = CLAMP (self->points[self->active_point].x, 0, 1);
+  self->points[self->active_point].y = CLAMP (self->points[self->active_point].y, 0, 1);
+
+  gtk_path_widget_create_paths (self);
+
+  gtk_widget_queue_draw (GTK_WIDGET (self));
+}
+
+static void
+pointer_motion (GtkEventControllerMotion *controller,
+                double                    x,
+                double                    y,
+                GtkPathWidget            *self)
+{
+  gsk_path_measure_get_closest_point_full (self->line_measure,
+                                           &GRAPHENE_POINT_INIT (x, y),
+                                           INFINITY,
+                                           NULL, NULL,
+                                           &self->line_closest,
+                                           NULL);
+
+  gtk_widget_queue_draw (GTK_WIDGET (self));
+}
+
+static void
+pointer_leave (GtkEventControllerMotion *controller,
+               GtkPathWidget            *self)
+{
+  self->line_closest = -1;
+
+  gtk_widget_queue_draw (GTK_WIDGET (self));
+}
+
+static void
+gtk_path_widget_init (GtkPathWidget *self)
+{
+  GtkEventController *controller;
+
+  controller = GTK_EVENT_CONTROLLER (gtk_gesture_drag_new ());
+  g_signal_connect (controller, "drag-begin", G_CALLBACK (drag_begin), self);
+  g_signal_connect (controller, "drag-update", G_CALLBACK (drag_update), self);
+  g_signal_connect (controller, "drag-end", G_CALLBACK (drag_update), self);
+  gtk_widget_add_controller (GTK_WIDGET (self), controller);
+
+  controller = GTK_EVENT_CONTROLLER (gtk_event_controller_motion_new ());
+  g_signal_connect (controller, "enter", G_CALLBACK (pointer_motion), self);
+  g_signal_connect (controller, "motion", G_CALLBACK (pointer_motion), self);
+  g_signal_connect (controller, "leave", G_CALLBACK (pointer_leave), self);
+  gtk_widget_add_controller (GTK_WIDGET (self), controller);
+
+  self->line_closest = -1;
+
+  self->points[0] = GRAPHENE_POINT_INIT (0.1, 0.9);
+  self->points[1] = GRAPHENE_POINT_INIT (0.3, 0.1);
+  self->points[2] = GRAPHENE_POINT_INIT (0.7, 0.1);
+  self->points[3] = GRAPHENE_POINT_INIT (0.9, 0.9);
+
+  self->background = GDK_PAINTABLE (gdk_texture_new_from_resource ("/sliding_puzzle/portland-rose.jpg"));
+
+  gtk_path_widget_set_text (self, "It's almost working");
+}
+
+GtkWidget *
+gtk_path_widget_new (void)
+{
+  GtkPathWidget *self;
+
+  self = g_object_new (GTK_TYPE_PATH_WIDGET, NULL);
+
+  return GTK_WIDGET (self);
+}
+
+GtkWidget *
+do_path_text (GtkWidget *do_widget)
+{
+  static GtkWidget *window = NULL;
+
+  if (!window)
+    {
+      GtkBuilder *builder;
+
+      g_type_ensure (GTK_TYPE_PATH_WIDGET);
+
+      builder = gtk_builder_new_from_resource ("/path_text/path_text.ui");
+      window = GTK_WIDGET (gtk_builder_get_object (builder, "window"));
+      gtk_window_set_display (GTK_WINDOW (window),
+                              gtk_widget_get_display (do_widget));
+      g_object_add_weak_pointer (G_OBJECT (window), (gpointer *) &window);
+      g_object_unref (builder);
+    }
+
+  if (!gtk_widget_get_visible (window))
+    gtk_widget_show (window);
+  else
+    gtk_window_destroy (GTK_WINDOW (window));
+
+  return window;
+}

demos/gtk-demo/path_text.ui

@@ -0,0 +1,38 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<interface>
+  <object class="GtkWindow" id="window">
+    <property name="title" translatable="yes">Text along a Path</property>
+    <child type="titlebar">
+      <object class="GtkHeaderBar">
+        <child type="end">
+          <object class="GtkToggleButton" id="edit-toggle">
+            <property name="icon-name">document-edit-symbolic</property>
+          </object>
+        </child>
+      </object>
+    </child>
+    <child>
+      <object class="GtkBox">
+        <property name="orientation">vertical</property>
+        <child>
+          <object class="GtkRevealer">
+            <property name="reveal-child" bind-source="edit-toggle" bind-property="active" bind-flags="sync-create"></property>
+            <child>
+              <object class="GtkEntry" id="text">
+                <property name="text">Through the looking glass</property>
+              </object>
+            </child>
+          </object>
+        </child>
+        <child>
+          <object class="GtkPathWidget" id="view">
+            <property name="editable" bind-source="edit-toggle" bind-property="active" bind-flags="sync-create"></property>
+            <property name="text" bind-source="text" bind-property="text" bind-flags="sync-create"></property>
+            <property name="hexpand">true</property>
+            <property name="vexpand">true</property>
+          </object>
+        </child>
+      </object>
+    </child>
+  </object>
+</interface>

gsk/broadway/gskbroadwayrenderer.c

@@ -269,6 +269,8 @@ collect_reused_child_nodes (GskRenderer *renderer,
     case GSK_BLEND_NODE:
     case GSK_CROSS_FADE_NODE:
     case GSK_BLUR_NODE:
+    case GSK_FILL_NODE:
+    case GSK_STROKE_NODE:
 
     default:
 
@@ -855,6 +857,8 @@ gsk_broadway_renderer_add_node (GskRenderer *renderer,
     case GSK_CROSS_FADE_NODE:
     case GSK_BLUR_NODE:
     case GSK_GL_SHADER_NODE:
+    case GSK_FILL_NODE:
+    case GSK_STROKE_NODE:
     default:
       break; /* Fallback */
     }

gsk/gl/gskglrenderjob.c

@@ -3767,6 +3767,11 @@ gsk_gl_render_job_visit_node (GskGLRenderJob      *job,
       gsk_gl_render_job_visit_as_fallback (job, node);
     break;
 
+    case GSK_FILL_NODE:
+    case GSK_STROKE_NODE:
+      gsk_gl_render_job_visit_as_fallback (job, node);
+    break;
+
     case GSK_NOT_A_RENDER_NODE:
     default:
       g_assert_not_reached ();

gsk/gsk-autocleanup.h

@@ -22,6 +22,8 @@
 
 #ifndef __GI_SCANNER__
 
+G_DEFINE_AUTOPTR_CLEANUP_FUNC(GskPath, gsk_path_unref)
+G_DEFINE_AUTOPTR_CLEANUP_FUNC(GskPathMeasure, gsk_path_measure_unref)
 G_DEFINE_AUTOPTR_CLEANUP_FUNC(GskRenderer, g_object_unref)
 G_DEFINE_AUTOPTR_CLEANUP_FUNC(GskRenderNode, gsk_render_node_unref)
 G_DEFINE_AUTOPTR_CLEANUP_FUNC(GskTransform, gsk_transform_unref)

gsk/gsk.h

@@ -21,11 +21,15 @@
 #define __GSK_H_INSIDE__
 
 #include <gsk/gskenums.h>
+#include <gsk/gskglshader.h>
+#include <gsk/gskpath.h>
+#include <gsk/gskpathbuilder.h>
+#include <gsk/gskpathmeasure.h>
 #include <gsk/gskrenderer.h>
 #include <gsk/gskrendernode.h>
 #include <gsk/gskroundedrect.h>
+#include <gsk/gskstroke.h>
 #include <gsk/gsktransform.h>
-#include <gsk/gskglshader.h>
 
 #include <gsk/gskcairorenderer.h>
 

gsk/gskboundingbox.c

@@ -0,0 +1,80 @@
+#include "config.h"
+
+#include "gskboundingboxprivate.h"
+
+GskBoundingBox *
+gsk_bounding_box_init (GskBoundingBox         *self,
+                       const graphene_point_t *a,
+                       const graphene_point_t *b)
+{
+  self->min.x = MIN (a->x, b->x);
+  self->min.y = MIN (a->y, b->y);
+  self->max.x = MAX (a->x, b->x);
+  self->max.y = MAX (a->y, b->y);
+  return self;
+}
+
+GskBoundingBox *
+gsk_bounding_box_init_copy (GskBoundingBox       *self,
+                            const GskBoundingBox *src)
+{
+  self->min = src->min;
+  self->max = src->max;
+  return self;
+}
+
+GskBoundingBox *
+gsk_bounding_box_init_from_rect (GskBoundingBox        *self,
+                                 const graphene_rect_t *bounds)
+{
+  self->min = bounds->origin;
+  self->max.x = bounds->origin.x + bounds->size.width;
+  self->max.y = bounds->origin.y + bounds->size.height;
+  return self;
+}
+
+void
+gsk_bounding_box_expand (GskBoundingBox         *self,
+                         const graphene_point_t *p)
+{
+  self->min.x = MIN (self->min.x, p->x);
+  self->min.y = MIN (self->min.y, p->y);
+  self->max.x = MAX (self->max.x, p->x);
+  self->max.y = MAX (self->max.y, p->y);
+}
+
+graphene_rect_t *
+gsk_bounding_box_to_rect (const GskBoundingBox  *self,
+                          graphene_rect_t       *rect)
+{
+  rect->origin = self->min;
+  rect->size.width = self->max.x - self->min.x;
+  rect->size.height = self->max.y - self->min.y;
+  return rect;
+}
+
+gboolean
+gsk_bounding_box_contains_point (const GskBoundingBox     *self,
+                                 const graphene_point_t *p)
+{
+  return self->min.x <= p->x && p->x <= self->max.x &&
+         self->min.y <= p->y && p->y <= self->max.y;
+}
+
+gboolean
+gsk_bounding_box_intersection (const GskBoundingBox *a,
+                               const GskBoundingBox *b,
+                               GskBoundingBox       *res)
+{
+  graphene_point_t min, max;
+
+  min.x = MAX (a->min.x, b->min.x);
+  min.y = MAX (a->min.y, b->min.y);
+  max.x = MIN (a->max.x, b->max.x);
+  max.y = MIN (a->max.y, b->max.y);
+
+  if (res)
+    gsk_bounding_box_init (res, &min, &max);
+
+  return min.x <= max.x && min.y <= max.y;
+}

gsk/gskboundingboxprivate.h

@@ -0,0 +1,44 @@
+#pragma once
+
+#include <gsk/gsktypes.h>
+
+G_BEGIN_DECLS
+
+typedef struct _GskBoundingBox GskBoundingBox;
+
+struct _GskBoundingBox {
+  graphene_point_t min;
+  graphene_point_t max;
+};
+
+GDK_AVAILABLE_IN_ALL
+GskBoundingBox * gsk_bounding_box_init (GskBoundingBox         *self,
+                                        const graphene_point_t *a,
+                                        const graphene_point_t *b);
+
+GDK_AVAILABLE_IN_ALL
+GskBoundingBox * gsk_bounding_box_init_copy (GskBoundingBox       *self,
+                                             const GskBoundingBox *src);
+
+GDK_AVAILABLE_IN_ALL
+GskBoundingBox * gsk_bounding_box_init_from_rect (GskBoundingBox        *self,
+                                                  const graphene_rect_t *bounds);
+
+GDK_AVAILABLE_IN_ALL
+void             gsk_bounding_box_expand (GskBoundingBox         *self,
+                                          const graphene_point_t *p);
+
+GDK_AVAILABLE_IN_ALL
+graphene_rect_t *gsk_bounding_box_to_rect        (const GskBoundingBox  *self,
+                                                  graphene_rect_t       *rect);
+
+GDK_AVAILABLE_IN_ALL
+gboolean         gsk_bounding_box_contains_point (const GskBoundingBox   *self,
+                                                  const graphene_point_t *p);
+
+GDK_AVAILABLE_IN_ALL
+gboolean         gsk_bounding_box_intersection (const GskBoundingBox *a,
+                                                const GskBoundingBox *b,
+                                                GskBoundingBox       *res);
+
+G_END_DECLS

gsk/gskcontourprivate.h

@@ -0,0 +1,132 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+
+#ifndef __GSK_CONTOUR_PRIVATE_H__
+#define __GSK_CONTOUR_PRIVATE_H__
+
+#include <gskpath.h>
+
+#include "gskpathopprivate.h"
+
+G_BEGIN_DECLS
+
+/* A path is flat if it contains no cubic or conic segments.
+ * A path is closed if all its contours end with a GSK_PATH_CLOSE
+ * operation.
+ */
+typedef enum
+{
+  GSK_PATH_FLAT,
+  GSK_PATH_CLOSED
+} GskPathFlags;
+
+typedef struct _GskContour GskContour;
+
+GskContour *            gsk_rect_contour_new                    (const graphene_rect_t  *rect);
+GskContour *            gsk_circle_contour_new                  (const graphene_point_t *center,
+                                                                 float                   radius,
+                                                                 float                   start_angle,
+                                                                 float                   end_angle);
+GskContour *            gsk_standard_contour_new                (GskPathFlags            flags,
+                                                                 const graphene_point_t *points,
+                                                                 gsize                   n_points,
+                                                                 const gskpathop        *ops,
+                                                                 gsize                   n_ops,
+                                                                 gssize                  offset);
+
+void                    gsk_contour_copy                        (GskContour *            dest,
+                                                                 const GskContour       *src);
+GskContour *            gsk_contour_dup                         (const GskContour       *src);
+
+GskContour *            gsk_contour_reverse                     (const GskContour       *src);
+
+gsize                   gsk_contour_get_size                    (const GskContour       *self);
+GskPathFlags            gsk_contour_get_flags                   (const GskContour       *self);
+void                    gsk_contour_print                       (const GskContour       *self,
+                                                                 GString                *string);
+gboolean                gsk_contour_get_bounds                  (const GskContour       *self,
+                                                                 graphene_rect_t        *bounds);
+gpointer                gsk_contour_init_measure                (const GskContour       *self,
+                                                                 float                   tolerance,
+                                                                 float                  *out_length);
+void                    gsk_contour_free_measure                (const GskContour       *self,
+                                                                 gpointer                data);
+gboolean                gsk_contour_foreach                     (const GskContour       *self,
+                                                                 float                   tolerance,
+                                                                 GskPathForeachFunc      func,
+                                                                 gpointer                user_data);
+void                    gsk_contour_get_start_end               (const GskContour       *self,
+                                                                 graphene_point_t       *start,
+                                                                 graphene_point_t       *end);
+void                    gsk_contour_get_point                   (const GskContour       *self,
+                                                                 gpointer                measure_data,
+                                                                 float                   distance,
+                                                                 graphene_point_t       *pos,
+                                                                 graphene_vec2_t        *tangent);
+float                   gsk_contour_get_curvature               (const GskContour       *self,
+                                                                 gpointer                measure_data,
+                                                                 float                   distance,
+                                                                 graphene_point_t       *center);
+gboolean                gsk_contour_get_closest_point           (const GskContour       *self,
+                                                                 gpointer                measure_data,
+                                                                 float                   tolerance,
+                                                                 const graphene_point_t *point,
+                                                                 float                   threshold,
+                                                                 float                  *out_distance,
+                                                                 graphene_point_t       *out_pos,
+                                                                 float                  *out_offset,
+                                                                 graphene_vec2_t        *out_tangent);
+int                     gsk_contour_get_winding                 (const GskContour       *self,
+                                                                 gpointer                measure_data,
+                                                                 const graphene_point_t *point,
+                                                                 gboolean               *on_edge);
+void                    gsk_contour_add_segment                 (const GskContour       *self,
+                                                                 GskPathBuilder         *builder,
+                                                                 gpointer                measure_data,
+                                                                 gboolean                emit_move_to,
+                                                                 float                   start,
+                                                                 float                   end);
+gboolean                gsk_contour_get_stroke_bounds           (const GskContour       *self,
+                                                                 const GskStroke        *stroke,
+                                                                 graphene_rect_t        *bounds);
+void                    gsk_contour_add_stroke                  (const GskContour       *contour,
+                                                                 GskPathBuilder         *builder,
+                                                                 GskStroke              *stroke);
+void                    gsk_contour_default_add_stroke          (const GskContour       *contour,
+                                                                 GskPathBuilder         *builder,
+                                                                 GskStroke              *stroke);
+
+void                    gsk_contour_offset                      (const GskContour       *contour,
+                                                                 GskPathBuilder         *builder,
+                                                                 float                   distance,
+                                                                 GskLineJoin             line_join,
+                                                                 float                   miter_limit);
+void                    gsk_contour_default_offset              (const GskContour       *contour,
+                                                                 GskPathBuilder         *builder,
+                                                                 float                   distance,
+                                                                 GskLineJoin             line_join,
+                                                                 float                   miter_limit);
+
+gboolean                gsk_contour_is_convex                   (const GskContour       *contour);
+
+G_END_DECLS
+
+#endif /* __GSK_CONTOUR_PRIVATE_H__ */
+

gsk/gskconvexity.c

@@ -0,0 +1,286 @@
+#include "config.h"
+
+#include "gskconvexityprivate.h"
+#include "gskcontourprivate.h"
+
+typedef enum
+{
+  GSK_DIR_CHANGE_UNKNOWN,
+  GSK_DIR_CHANGE_LEFT,
+  GSK_DIR_CHANGE_RIGHT,
+  GSK_DIR_CHANGE_STRAIGHT,
+  GSK_DIR_CHANGE_REVERSE,
+  GSK_DIR_CHANGE_INVALID,
+} GskDirChange;
+
+typedef enum
+{
+  GSK_PATH_DIRECTION_UNKNOWN,
+  GSK_PATH_DIRECTION_CLOCKWISE,
+  GSK_PATH_DIRECTION_COUNTERCLOCKWISE,
+} GskPathDirection;
+
+typedef struct _GskConvexityChecker GskConvexityChecker;
+struct _GskConvexityChecker
+{
+  graphene_point_t first_point;
+  graphene_vec2_t first_vec;
+  graphene_point_t last_point;
+  graphene_vec2_t last_vec;
+  GskDirChange expected_direction;
+  GskPathDirection first_direction;
+  int reversals;
+  gboolean finite;
+  GskConvexity convexity;
+  int xsign;
+  int ysign;
+  int dx;
+  int dy;
+};
+
+static float
+cross_product (graphene_vec2_t *a,
+               graphene_vec2_t *b)
+{
+  float fa[2];
+  float fb[2];
+  graphene_vec2_to_float (a, fa);
+  graphene_vec2_to_float (b, fb);
+  return fa[0] * fb[1] - fa[1] * fb[0];
+}
+
+static GskDirChange
+direction_change (GskConvexityChecker    *c,
+                  graphene_vec2_t *v)
+{
+  float cross = cross_product (&(c->last_vec), v);
+  if (!finite (cross))
+    return GSK_DIR_CHANGE_UNKNOWN;
+
+  if (cross == 0)
+    return graphene_vec2_dot (&(c->last_vec), v) < 0
+           ? GSK_DIR_CHANGE_REVERSE
+           : GSK_DIR_CHANGE_STRAIGHT;
+
+  return cross > 0
+         ? GSK_DIR_CHANGE_RIGHT
+         : GSK_DIR_CHANGE_LEFT;
+}
+
+static gboolean
+add_vec (GskConvexityChecker *c,
+         graphene_vec2_t     *v)
+{
+  GskDirChange dir;
+  int sign;
+
+  dir = direction_change (c, v);
+  switch (dir)
+    {
+    case GSK_DIR_CHANGE_LEFT:
+    case GSK_DIR_CHANGE_RIGHT:
+      if (c->expected_direction == GSK_DIR_CHANGE_INVALID)
+        {
+          c->expected_direction = dir;
+          c->first_direction = (dir == GSK_DIR_CHANGE_RIGHT)
+                               ? GSK_PATH_DIRECTION_CLOCKWISE
+                               : GSK_PATH_DIRECTION_COUNTERCLOCKWISE;
+        }
+      else if (c->expected_direction != dir)
+        {
+          c->first_direction = GSK_PATH_DIRECTION_UNKNOWN;
+          c->convexity = GSK_CONVEXITY_CONCAVE;
+          return FALSE;
+        }
+      graphene_vec2_init_from_vec2 (&c->last_vec, v);
+      break;
+
+    case GSK_DIR_CHANGE_STRAIGHT:
+      break;
+
+    case GSK_DIR_CHANGE_REVERSE:
+      graphene_vec2_init_from_vec2 (&c->last_vec, v);
+      c->reversals++;
+      if (c->reversals > 2)
+        c->convexity = GSK_CONVEXITY_CONCAVE;
+      return c->reversals < 3;
+
+    case GSK_DIR_CHANGE_UNKNOWN:
+      c->finite = FALSE;
+      return FALSE;
+
+    case GSK_DIR_CHANGE_INVALID:
+    default:
+      g_assert_not_reached ();
+    }
+
+  if (graphene_vec2_get_x (v) > 0)
+    sign = 1;
+  else if (graphene_vec2_get_x (v) < 0)
+    sign = -1;
+  else
+    sign = 0;
+
+  if (sign != 0)
+    {
+      if (c->xsign != 42)
+        {
+          if (c->xsign != sign)
+            c->dx++;
+
+          if (c->dx > 2)
+            {
+              c->convexity = GSK_CONVEXITY_CONCAVE;
+              return FALSE;
+            }
+        }
+      c->xsign = sign;
+    }
+
+  if (graphene_vec2_get_y (v) > 0)
+    sign = 1;
+  else if (graphene_vec2_get_y (v) < 0)
+    sign = -1;
+  else
+    sign = 0;
+
+  if (sign != 0)
+    {
+      if (c->ysign != 42)
+        {
+          if (c->ysign != sign)
+            c->dy++;
+
+          if (c->dy > 2)
+            {
+              c->convexity = GSK_CONVEXITY_CONCAVE;
+              return FALSE;
+            }
+        }
+      c->ysign = sign;
+    }
+
+  return TRUE;
+}
+
+static void
+gsk_convexity_checker_init (GskConvexityChecker *c)
+{
+  c->first_point = GRAPHENE_POINT_INIT(0,0);
+  c->last_point = GRAPHENE_POINT_INIT(0,0);
+  graphene_vec2_init (&c->first_vec, 0, 0);
+  graphene_vec2_init (&c->last_vec, 0, 0);
+  c->expected_direction = GSK_DIR_CHANGE_INVALID;
+  c->first_direction = GSK_PATH_DIRECTION_UNKNOWN;
+  c->reversals = 0;
+  c->finite = TRUE;
+  c->convexity = GSK_CONVEXITY_UNKNOWN;
+  c->xsign = 42;
+  c->ysign = 42;
+  c->dx = 0;
+  c->dy = 0;
+}
+
+static void
+gsk_convexity_checker_move (GskConvexityChecker    *c,
+                            const graphene_point_t *p)
+{
+  c->first_point = c->last_point = *p;
+  c->expected_direction = GSK_DIR_CHANGE_INVALID;
+  c->convexity = GSK_CONVEXITY_CONVEX;
+}
+
+static gboolean
+gsk_convexity_checker_add_point (GskConvexityChecker    *c,
+                                 const graphene_point_t *p)
+{
+  graphene_vec2_t v;
+
+  if (graphene_point_equal (&c->last_point, p))
+    return TRUE;
+
+  graphene_vec2_init (&v,
+                      p->x - c->last_point.x,
+                      p->y - c->last_point.y);
+
+  if (graphene_point_equal (&c->first_point, &c->last_point) &&
+      c->expected_direction == GSK_DIR_CHANGE_INVALID)
+    {
+      graphene_vec2_init_from_vec2 (&c->last_vec, &v);
+      graphene_vec2_init_from_vec2 (&c->first_vec, &v);
+    }
+  else if (!add_vec (c, &v))
+    {
+      c->convexity = GSK_CONVEXITY_CONCAVE;
+      return FALSE;
+    }
+
+  c->last_point = *p;
+  return TRUE;
+}
+
+static gboolean
+gsk_convexity_checker_close (GskConvexityChecker *c)
+{
+  if (!(gsk_convexity_checker_add_point (c, &c->first_point) &&
+        add_vec (c, &c->first_vec)))
+    {
+      c->convexity = GSK_CONVEXITY_CONCAVE;
+      return FALSE;
+    }
+
+  return TRUE;
+}
+
+static gboolean
+convex_cb (GskPathOperation        op,
+           const graphene_point_t *pts,
+           gsize                   n_pts,
+           float                   weight,
+           gpointer                user_data)
+{
+  GskConvexityChecker *c = user_data;
+
+  switch (op)
+    {
+    case GSK_PATH_MOVE:
+      gsk_convexity_checker_move (c, &pts[0]);
+      break;
+    case GSK_PATH_CLOSE:
+      if (!gsk_convexity_checker_close (c))
+        return FALSE;
+      break;
+    case GSK_PATH_LINE:
+      if (!gsk_convexity_checker_add_point (c, &pts[1]))
+        return FALSE;
+      break;
+    case GSK_PATH_CURVE:
+      if (!gsk_convexity_checker_add_point (c, &pts[1]) ||
+          !gsk_convexity_checker_add_point (c, &pts[2]) ||
+          !gsk_convexity_checker_add_point (c, &pts[3]))
+        return FALSE;
+      break;
+    case GSK_PATH_CONIC:
+      if (!gsk_convexity_checker_add_point (c, &pts[1]) ||
+          !gsk_convexity_checker_add_point (c, &pts[3]))
+        return FALSE;
+      break;
+    default:
+      g_assert_not_reached ();
+    }
+
+  return TRUE;
+}
+
+GskConvexity
+gsk_contour_compute_convexity (const GskContour *contour)
+{
+  GskConvexityChecker c;
+
+  gsk_convexity_checker_init (&c);
+  gsk_contour_foreach (contour, 0.001, convex_cb, &c);
+
+  g_assert (c.convexity != GSK_CONVEXITY_UNKNOWN);
+
+  return c.convexity;
+}

gsk/gskconvexityprivate.h

@@ -0,0 +1,14 @@
+#pragma once
+
+#include "gskcontourprivate.h"
+
+typedef enum
+{
+  GSK_CONVEXITY_UNKNOWN,
+  GSK_CONVEXITY_CONVEX,
+  GSK_CONVEXITY_CONCAVE,
+} GskConvexity;
+
+GskConvexity gsk_contour_compute_convexity (const GskContour *contour);
+
+

gsk/gskcurveintersect.c

@@ -0,0 +1,621 @@
+/*
+ * Copyright © 2020 Red Hat, Inc
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Matthias Clasen <mclasen@redhat.com>
+ */
+
+#include "config.h"
+
+#include "gskcurveprivate.h"
+
+static inline gboolean
+acceptable (float t)
+{
+  return 0 - FLT_EPSILON <= t && t <= 1 + FLT_EPSILON;
+}
+
+
+static int
+line_intersect (const GskCurve   *curve1,
+                const GskCurve   *curve2,
+                float            *t1,
+                float            *t2,
+                graphene_point_t *p,
+                int               n)
+{
+  const graphene_point_t *pts1 = curve1->line.points;
+  const graphene_point_t *pts2 = curve2->line.points;
+  float a1 = pts1[0].x - pts1[1].x;
+  float b1 = pts1[0].y - pts1[1].y;
+  float a2 = pts2[0].x - pts2[1].x;
+  float b2 = pts2[0].y - pts2[1].y;
+  float det = a1 * b2 - b1 * a2;
+
+  if (fabs(det) > 0.01)
+    {
+      float tt =   ((pts1[0].x - pts2[0].x) * b2 - (pts1[0].y - pts2[0].y) * a2) / det;
+      float ss = - ((pts1[0].y - pts2[0].y) * a1 - (pts1[0].x - pts2[0].x) * b1) / det;
+
+      if (acceptable (tt) && acceptable (ss))
+        {
+          p[0].x = pts1[0].x + tt * (pts1[1].x - pts1[0].x);
+          p[0].y = pts1[0].y + tt * (pts1[1].y - pts1[0].y);
+
+          t1[0] = tt;
+          t2[0] = ss;
+
+          return 1;
+        }
+    }
+  else /* parallel lines */
+    {
+      float r = a1 * (pts1[1].y - pts2[0].y) - (pts1[1].x - pts2[0].x) * b1;
+      float dist = (r * r) / (a1 * a1 + b1 * b1);
+      float t, s, tt, ss;
+
+      if (dist > 0.01)
+        return 0;
+
+      if (pts1[1].x != pts1[0].x)
+        {
+          t = (pts2[0].x - pts1[0].x) / (pts1[1].x - pts1[0].x);
+          s = (pts2[1].x - pts1[0].x) / (pts1[1].x - pts1[0].x);
+        }
+      else
+        {
+          t = (pts2[0].y - pts1[0].y) / (pts1[1].y - pts1[0].y);
+          s = (pts2[1].y - pts1[0].y) / (pts1[1].y - pts1[0].y);
+        }
+
+      if ((t < 0 && s < 0) || (t > 1 && s > 1))
+        return 0;
+
+      if (acceptable (t))
+        {
+          t1[0] = t;
+          t2[0] = 0;
+          p[0] = pts2[0];
+        }
+      else if (t < 0)
+        {
+          if (pts2[1].x != pts2[0].x)
+            tt = (pts1[0].x - pts2[0].x) / (pts2[1].x - pts2[0].x);
+          else
+            tt = (pts1[0].y - pts2[0].y) / (pts2[1].y - pts2[0].y);
+
+          t1[0] = 0;
+          t2[0] = tt;
+          p[0] = pts1[0];
+        }
+      else
+        {
+          if (pts2[1].x != pts2[0].x)
+            tt = (pts1[1].x - pts2[0].x) / (pts2[1].x - pts2[0].x);
+          else
+            tt = (pts1[1].y - pts2[0].y) / (pts2[1].y - pts2[0].y);
+
+          t1[0] = 1;
+          t2[0] = tt;
+          p[0] = pts1[1];
+        }
+
+      if (acceptable (s))
+        {
+          if (t2[0] == 1)
+            return 1;
+
+          t1[1] = s;
+          t2[1] = 1;
+          p[1] = pts2[1];
+        }
+      else if (s < 0)
+        {
+          if (t1[0] == 0)
+            return 1;
+
+          if (pts2[1].x != pts2[0].x)
+            ss = (pts1[0].x - pts2[0].x) / (pts2[1].x - pts2[0].x);
+          else
+            ss = (pts1[0].y - pts2[0].y) / (pts2[1].y - pts2[0].y);
+
+          t1[1] = 0;
+          t2[1] = ss;
+          p[1] = pts1[0];
+        }
+      else
+        {
+          if (t1[0] == 1)
+            return 1;
+
+          if (pts2[1].x != pts2[0].x)
+            ss = (pts1[1].x - pts2[0].x) / (pts2[1].x - pts2[0].x);
+          else
+            ss = (pts1[1].y - pts2[0].y) / (pts2[1].y - pts2[0].y);
+
+          t1[1] = 1;
+          t2[1] = ss;
+          p[1] = pts1[1];
+        }
+
+      return 2;
+    }
+
+  return 0;
+}
+
+static void
+get_tangent (const graphene_point_t *p0,
+             const graphene_point_t *p1,
+             graphene_vec2_t        *t)
+{
+  graphene_vec2_init (t, p1->x - p0->x, p1->y - p0->y);
+  graphene_vec2_normalize (t, t);
+}
+
+static void
+align_points (const graphene_point_t *p,
+              const graphene_point_t *a,
+              const graphene_point_t *b,
+              graphene_point_t       *q,
+              int                     n)
+{
+  graphene_vec2_t n1;
+  float angle;
+  float s, c;
+  float dist;
+
+  get_tangent (a, b, &n1);
+  angle = - atan2 (graphene_vec2_get_y (&n1), graphene_vec2_get_x (&n1));
+  sincosf (angle, &s, &c);
+
+  dist = sqrtf ((a->x - b->x)*(a->x - b->x) + (a->y - b->y)*(a->y - b->y));
+
+  for (int i = 0; i < n; i++)
+    {
+      q[i].x = ((p[i].x - a->x) * c - (p[i].y - a->y) * s) / dist;
+      q[i].y = ((p[i].x - a->x) * s + (p[i].y - a->y) * c) / dist;
+    }
+}
+
+static void
+find_point_on_line (const graphene_point_t *p1,
+                    const graphene_point_t *p2,
+                    const graphene_point_t *q,
+                    float                  *t)
+{
+  if (p2->x != p1->x)
+    *t = (q->x - p1->x) / (p2->x - p1->x);
+  else
+    *t = (q->y - p1->y) / (p2->y - p1->y);
+}
+
+static float
+cuberoot (float v)
+{
+  if (v < 0)
+    return -pow (-v, 1.f / 3);
+  return pow (v, 1.f / 3);
+}
+
+/* Solve P = 0 where P is
+ * P = (1-t)^3*pa + 3*t*(1-t)^2*pb + 3*t^2*(1-t)*pc + t^3*pd
+ */
+static int
+get_cubic_roots (float pa, float pb, float pc, float pd, float roots[3])
+{
+  float a, b, c, d;
+  float q, q2;
+  float p, p3;
+  float discriminant;
+  float u1, v1, sd;
+  int n_roots = 0;
+
+  d = -pa + 3*pb - 3*pc + pd;
+  a = 3*pa - 6*pb + 3*pc;
+  b = -3*pa + 3*pb;
+  c = pa;
+
+  if (fabs (d) < 0.0001)
+    {
+      if (fabs (a) < 0.0001)
+        {
+          if (fabs (b) < 0.0001)
+            return 0;
+
+          if (acceptable (-c / b))
+            {
+              roots[0] = -c / b;
+
+              return 1;
+            }
+
+          return 0;
+        }
+      q = sqrt (b*b - 4*a*c);
+      roots[n_roots] = (-b + q) / (2 * a);
+      if (acceptable (roots[n_roots]))
+        n_roots++;
+
+      roots[n_roots] = (-b - q) / (2 * a);
+      if (acceptable (roots[n_roots]))
+        n_roots++;
+
+      return n_roots;
+    }
+
+  a /= d;
+  b /= d;
+  c /= d;
+
+  p = (3*b - a*a)/3;
+  p3 = p/3;
+  q = (2*a*a*a - 9*a*b + 27*c)/27;
+  q2 = q/2;
+  discriminant = q2*q2 + p3*p3*p3;
+
+  if (discriminant < 0)
+    {
+      float mp3 = -p/3;
+      float mp33 = mp3*mp3*mp3;
+      float r = sqrt (mp33);
+      float t = -q / (2*r);
+      float cosphi = t < -1 ? -1 : (t > 1 ? 1 : t);
+      float phi = acos (cosphi);
+      float crtr = cuberoot (r);
+      float t1 = 2*crtr;
+
+      roots[n_roots] = t1 * cos (phi/3) - a/3;
+      if (acceptable (roots[n_roots]))
+        n_roots++;
+      roots[n_roots] = t1 * cos ((phi + 2*M_PI) / 3) - a/3;
+      if (acceptable (roots[n_roots]))
+        n_roots++;
+      roots[n_roots] = t1 * cos ((phi + 4*M_PI) / 3) - a/3;
+      if (acceptable (roots[n_roots]))
+        n_roots++;
+
+    return n_roots;
+  }
+
+  if (discriminant == 0)
+    {
+      u1 = q2 < 0 ? cuberoot (-q2) : -cuberoot (q2);
+      roots[n_roots] = 2*u1 - a/3;
+      if (acceptable (roots[n_roots]))
+        n_roots++;
+      roots[n_roots] = -u1 - a/3;
+      if (acceptable (roots[n_roots]))
+        n_roots++;
+
+      return n_roots;
+    }
+
+  sd = sqrt (discriminant);
+  u1 = cuberoot (sd - q2);
+  v1 = cuberoot (sd + q2);
+  roots[n_roots] = u1 - v1 - a/3;
+  if (acceptable (roots[n_roots]))
+    n_roots++;
+
+  return n_roots;
+}
+
+static int
+line_curve_intersect (const GskCurve   *curve1,
+                      const GskCurve   *curve2,
+                      float            *t1,
+                      float            *t2,
+                      graphene_point_t *p,
+                      int               n)
+{
+  const graphene_point_t *a = &curve1->line.points[0];
+  const graphene_point_t *b = &curve1->line.points[1];
+  graphene_point_t pts[4];
+  float t[3];
+  int m, i, j;
+
+  /* Rotate things to place curve1 on the x axis,
+   * then solve curve2 for y == 0.
+   */
+  align_points (curve2->curve.points, a, b, pts, 4);
+
+  m = get_cubic_roots (pts[0].y, pts[1].y, pts[2].y, pts[3].y, t);
+
+  j = 0;
+  for (i = 0; i < m; i++)
+    {
+      t2[j] = t[i];
+      gsk_curve_get_point (curve2, t2[j], &p[j]);
+      find_point_on_line (a, b, &p[j], &t1[j]);
+      if (acceptable (t1[j]))
+        j++;
+      if (j == n)
+        break;
+    }
+
+  return j;
+}
+
+static void
+curve_intersect_recurse (const GskCurve   *curve1,
+                         const GskCurve   *curve2,
+                         float             t1l,
+                         float             t1r,
+                         float             t2l,
+                         float             t2r,
+                         float            *t1,
+                         float            *t2,
+                         graphene_point_t *p,
+                         int               n,
+                         int              *pos,
+                         float             tolerance)
+{
+  GskCurve p11, p12, p21, p22;
+  GskBoundingBox b1, b2;
+  float d1, d2;
+
+  if (*pos == n)
+    return;
+
+  gsk_curve_get_tight_bounds (curve1, &b1);
+  gsk_curve_get_tight_bounds (curve2, &b2);
+
+  if (!gsk_bounding_box_intersection (&b1, &b2, NULL))
+    return;
+
+  d1 = (t1r - t1l) / 2;
+  d2 = (t2r - t2l) / 2;
+
+  if (b1.max.x - b1.min.x < tolerance && b1.max.y - b1.min.y < tolerance &&
+      b2.max.x - b2.min.x < tolerance && b2.max.y - b2.min.y < tolerance)
+    {
+      graphene_point_t c;
+      t1[*pos] = t1l + d1;
+      t2[*pos] = t2l + d2;
+      gsk_curve_get_point (curve1, 0.5, &c);
+
+      for (int i = 0; i < *pos; i++)
+        {
+          if (graphene_point_near (&c, &p[i], 0.1))
+            return;
+        }
+
+      p[*pos] = c;
+      (*pos)++;
+
+      return;
+    }
+
+  gsk_curve_split (curve1, 0.5, &p11, &p12);
+  gsk_curve_split (curve2, 0.5, &p21, &p22);
+
+  curve_intersect_recurse (&p11, &p21, t1l,      t1l + d1, t2l,      t2l + d2, t1, t2, p, n, pos, tolerance);
+  curve_intersect_recurse (&p11, &p22, t1l,      t1l + d1, t2l + d2, t2r,      t1, t2, p, n, pos, tolerance);
+  curve_intersect_recurse (&p12, &p21, t1l + d1, t1r,      t2l,      t2l + d2, t1, t2, p, n, pos, tolerance);
+  curve_intersect_recurse (&p12, &p22, t1l + d1, t1r,      t2l + d2, t2r,      t1, t2, p, n, pos, tolerance);
+}
+
+static int
+curve_intersect (const GskCurve   *curve1,
+                 const GskCurve   *curve2,
+                 float            *t1,
+                 float            *t2,
+                 graphene_point_t *p,
+                 int               n,
+                 float             tolerance)
+{
+  int pos = 0;
+
+  curve_intersect_recurse (curve1, curve2, 0, 1, 0, 1, t1, t2, p, n, &pos, tolerance);
+
+  return pos;
+}
+
+static void
+get_bounds (const GskCurve  *curve,
+            float            tl,
+            float            tr,
+            GskBoundingBox  *bounds)
+{
+  GskCurve c;
+
+  gsk_curve_segment (curve, tl, tr, &c);
+  gsk_curve_get_tight_bounds (&c, bounds);
+}
+
+static void
+general_intersect_recurse (const GskCurve   *curve1,
+                           const GskCurve   *curve2,
+                           float             t1l,
+                           float             t1r,
+                           float             t2l,
+                           float             t2r,
+                           float            *t1,
+                           float            *t2,
+                           graphene_point_t *p,
+                           int               n,
+                           int              *pos,
+                           float             tolerance)
+{
+  GskBoundingBox b1, b2;
+  float d1, d2;
+
+  if (*pos == n)
+    return;
+
+  get_bounds (curve1, t1l, t1r, &b1);
+  get_bounds (curve2, t2l, t2r, &b2);
+
+  if (!gsk_bounding_box_intersection (&b1, &b2, NULL))
+    return;
+
+  d1 = (t1r - t1l) / 2;
+  d2 = (t2r - t2l) / 2;
+
+  if (b1.max.x - b1.min.x < tolerance && b1.max.y - b1.min.y < tolerance &&
+      b2.max.x - b2.min.x < tolerance && b2.max.y - b2.min.y < tolerance)
+    {
+      graphene_point_t c;
+      t1[*pos] = t1l + d1;
+      t2[*pos] = t2l + d2;
+      gsk_curve_get_point (curve1, t1[*pos], &c);
+
+      for (int i = 0; i < *pos; i++)
+        {
+          if (graphene_point_near (&c, &p[i], tolerance))
+            return;
+        }
+
+      p[*pos] = c;
+      (*pos)++;
+
+      return;
+    }
+
+  /* Note that in the conic case, we cannot just split the curves and
+   * pass the two halves down, since splitting changes the parametrization,
+   * and we need the t's to be valid parameters wrt to the original curve.
+   *
+   * So, instead, we determine the bounding boxes above by always starting
+   * from the original curve. That is a bit less efficient, but also works
+   * for conics.
+   */
+  general_intersect_recurse (curve1, curve2, t1l,      t1l + d1, t2l,      t2l + d2, t1, t2, p, n, pos, tolerance);
+  general_intersect_recurse (curve1, curve2, t1l,      t1l + d1, t2l + d2, t2r,      t1, t2, p, n, pos, tolerance);
+  general_intersect_recurse (curve1, curve2, t1l + d1, t1r,      t2l,      t2l + d2, t1, t2, p, n, pos, tolerance);
+  general_intersect_recurse (curve1, curve2, t1l + d1, t1r,      t2l + d2, t2r,      t1, t2, p, n, pos, tolerance);
+}
+
+static int
+general_intersect (const GskCurve   *curve1,
+                   const GskCurve   *curve2,
+                   float            *t1,
+                   float            *t2,
+                   graphene_point_t *p,
+                   int               n,
+                   float             tolerance)
+{
+  int pos = 0;
+
+  general_intersect_recurse (curve1, curve2, 0, 1, 0, 1, t1, t2, p, n, &pos, tolerance);
+
+  return pos;
+}
+
+static int
+curve_self_intersect (const GskCurve   *curve,
+                      float            *t1,
+                      float            *t2,
+                      graphene_point_t *p,
+                      int               n)
+{
+  float tt[3], ss[3], s;
+  graphene_point_t pp[3];
+  int m;
+  GskCurve cs, ce;
+
+  if (curve->op != GSK_PATH_CURVE)
+    return 0;
+
+  s = 0.5;
+  m = gsk_curve_get_curvature_points (curve, tt);
+  for (int i = 0; i < m; i++)
+    {
+      if (gsk_curve_get_curvature (curve, tt[i], NULL) == 0)
+        {
+          s = tt[i];
+          break;
+        }
+    }
+
+  gsk_curve_split (curve, s, &cs, &ce);
+
+  m = curve_intersect (&cs, &ce, tt, ss, pp, 3, 0.001);
+
+  if (m > 1)
+    {
+      /* One of the (at most 2) intersections we found
+       * must be the common point where we split the curve.
+       * It will have a t value of 1 and an s value of 0.
+       */
+      if (fabs (tt[0] - 1) > 1e-3)
+        {
+          t1[0] = t2[0] = tt[0] * s;
+          p[0] = pp[0];
+        }
+      else if (fabs (tt[1] - 1) > 1e-3)
+        {
+          t1[0] = t2[0] = tt[1] * s;
+          p[0] = pp[1];
+        }
+      if (fabs (ss[0]) > 1e-3)
+        {
+          t1[1] = t2[1] = s + ss[0] * (1 - s);
+          p[1] = pp[0];
+        }
+      else if (fabs (ss[1]) > 1e-3)
+        {
+          t1[1] = t2[1] = s + ss[1] * (1 - s);
+          p[1] = pp[1];
+        }
+
+      return 2;
+    }
+
+  return 0;
+}
+
+/* Place intersections between the curves in p, and their Bezier positions
+ * in t1 and t2, up to n. Return the number of intersections found.
+ *
+ * Note that two cubic Beziers can have up to 9 intersections.
+ */
+int
+gsk_curve_intersect (const GskCurve   *curve1,
+                     const GskCurve   *curve2,
+                     float            *t1,
+                     float            *t2,
+                     graphene_point_t *p,
+                     int               n)
+{
+  GskPathOperation op1 = curve1->op;
+  GskPathOperation op2 = curve2->op;
+
+  if (op1 == GSK_PATH_CLOSE)
+    op1 = GSK_PATH_LINE;
+
+  if (op2 == GSK_PATH_CLOSE)
+    op2 = GSK_PATH_LINE;
+
+  if (memcmp (curve1, curve2, sizeof (GskCurve)) == 0)
+    return curve_self_intersect (curve1, t1, t2, p, n);
+
+  /* We special-case line-line and line-curve intersections,
+   * since we can solve them directly.
+   * Everything else is done via bisection.
+   */
+  if (op1 == GSK_PATH_LINE && op2 == GSK_PATH_LINE)
+    return line_intersect (curve1, curve2, t1, t2, p, n);
+  else if (op1 == GSK_PATH_LINE && op2 == GSK_PATH_CURVE)
+    return line_curve_intersect (curve1, curve2, t1, t2, p, n);
+  else if (op1 == GSK_PATH_CURVE && op2 == GSK_PATH_LINE)
+    return line_curve_intersect (curve2, curve1, t2, t1, p, n);
+  else if (op1 == GSK_PATH_CURVE && op2 == GSK_PATH_CURVE)
+    return curve_intersect (curve1, curve2, t1, t2, p, n, 0.001);
+  else
+    return general_intersect (curve1, curve2, t1, t2, p, n, 0.001);
+
+}

gsk/gskcurveprivate.h

@@ -0,0 +1,164 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+
+#ifndef __GSK_CURVE_PRIVATE_H__
+#define __GSK_CURVE_PRIVATE_H__
+
+#include "gskpathopprivate.h"
+#include "gskboundingboxprivate.h"
+
+G_BEGIN_DECLS
+
+typedef gpointer gskpathop;
+
+typedef union _GskCurve GskCurve;
+
+typedef struct _GskLineCurve GskLineCurve;
+typedef struct _GskCurveCurve GskCurveCurve;
+typedef struct _GskConicCurve GskConicCurve;
+
+struct _GskLineCurve
+{
+  GskPathOperation op;
+
+  gboolean padding;
+
+  graphene_point_t points[2];
+};
+
+struct _GskCurveCurve
+{
+  GskPathOperation op;
+
+  gboolean has_coefficients;
+
+  graphene_point_t points[4];
+
+  graphene_point_t coeffs[4];
+};
+
+struct _GskConicCurve
+{
+  GskPathOperation op;
+
+  gboolean has_coefficients;
+
+  /* points[0], points[1], points[3] are the control points,
+   * points[2].x is the weight
+   */
+  graphene_point_t points[4];
+
+  graphene_point_t num[3];
+  graphene_point_t denom[3];
+};
+
+union _GskCurve
+{
+  GskPathOperation op;
+  GskLineCurve line;
+  GskCurveCurve curve;
+  GskConicCurve conic;
+};
+
+typedef gboolean (* GskCurveAddLineFunc) (const graphene_point_t *from,
+                                          const graphene_point_t *to,
+                                          float                   from_progress,
+                                          float                   to_progress,
+                                          gpointer                user_data);
+
+typedef gboolean (* GskCurveAddCurveFunc) (const graphene_point_t points[4],
+                                           gpointer                user_data);
+
+void                    gsk_curve_init                          (GskCurve               *curve,
+                                                                 gskpathop               op);
+void                    gsk_curve_init_foreach                  (GskCurve               *curve,
+                                                                 GskPathOperation        op,
+                                                                 const graphene_point_t *pts,
+                                                                 gsize                   n_pts,
+                                                                 float                   weight);
+
+void                    gsk_curve_get_point                     (const GskCurve         *curve,
+                                                                 float                   progress,
+                                                                 graphene_point_t       *pos);
+void                    gsk_curve_get_tangent                   (const GskCurve         *curve,
+                                                                 float                   progress,
+                                                                 graphene_vec2_t        *tangent);
+void                    gsk_curve_get_normal                    (const GskCurve         *curve,
+                                                                 float                   progress,
+                                                                 graphene_vec2_t        *normal);
+void                    gsk_curve_split                         (const GskCurve         *curve,
+                                                                 float                   progress,
+                                                                 GskCurve               *start,
+                                                                 GskCurve               *end);
+void                    gsk_curve_segment                       (const GskCurve         *curve,
+                                                                 float                   start,
+                                                                 float                   end,
+                                                                 GskCurve               *segment);
+gboolean                gsk_curve_decompose                     (const GskCurve         *curve,
+                                                                 float                   tolerance,
+                                                                 GskCurveAddLineFunc     add_line_func,
+                                                                 gpointer                user_data);
+gboolean                gsk_curve_decompose_curve               (const GskCurve         *curve,
+                                                                 float                   tolerance,
+                                                                 GskCurveAddCurveFunc    add_curve_func,
+                                                                 gpointer                user_data);
+gskpathop               gsk_curve_pathop                        (const GskCurve         *curve);
+#define gsk_curve_builder_to(curve, builder) gsk_path_builder_pathop_to ((builder), gsk_curve_pathop (curve))
+const graphene_point_t *gsk_curve_get_start_point               (const GskCurve         *curve);
+const graphene_point_t *gsk_curve_get_end_point                 (const GskCurve         *curve);
+void                    gsk_curve_get_start_tangent             (const GskCurve         *curve,
+                                                                 graphene_vec2_t        *tangent);
+void                    gsk_curve_get_end_tangent               (const GskCurve         *curve,
+                                                                 graphene_vec2_t        *tangent);
+void                    gsk_curve_get_bounds                    (const GskCurve         *curve,
+                                                                 GskBoundingBox         *bounds);
+void                    gsk_curve_get_tight_bounds              (const GskCurve         *curve,
+                                                                 GskBoundingBox         *bounds);
+
+int                     gsk_curve_intersect                     (const GskCurve         *curve1,
+                                                                 const GskCurve         *curve2,
+                                                                 float                  *t1,
+                                                                 float                  *t2,
+                                                                 graphene_point_t       *p,
+                                                                 int                     n);
+
+void                    gsk_curve_offset                        (const GskCurve         *curve,
+                                                                 float                   distance,
+                                                                 GskCurve               *offset_curve);
+void                    gsk_curve_reverse                       (const GskCurve         *curve,
+                                                                 GskCurve               *reverse);
+
+float                   gsk_curve_get_curvature                 (const GskCurve         *curve,
+                                                                 float                   t,
+                                                                 graphene_point_t       *center);
+
+int                     gsk_curve_get_curvature_points          (const GskCurve         *curve,
+                                                                 float                   t[3]);
+
+int                     gsk_curve_get_cusps                     (const GskCurve         *curve,
+                                                                 float                   t[2]);
+
+void                    gsk_curve_print                         (const GskCurve         *curve);
+
+
+G_END_DECLS
+
+#endif /* __GSK_CURVE_PRIVATE_H__ */
+

gsk/gskdebug.c

@@ -10,6 +10,7 @@ static const GdkDebugKey gsk_debug_keys[] = {
   { "surface", GSK_DEBUG_SURFACE, "Information about surfaces" },
   { "fallback", GSK_DEBUG_FALLBACK, "Information about fallbacks" },
   { "glyphcache", GSK_DEBUG_GLYPH_CACHE, "Information about glyph caching" },
+  { "paths", GSK_DEBUG_PATHS, "Information about path processing" },
   { "geometry", GSK_DEBUG_GEOMETRY, "Show borders (when using cairo)" },
   { "full-redraw", GSK_DEBUG_FULL_REDRAW, "Force full redraws" },
   { "sync", GSK_DEBUG_SYNC, "Sync after each frame" },

gsk/gskdebugprivate.h

@@ -14,6 +14,7 @@ typedef enum {
   GSK_DEBUG_VULKAN                = 1 <<  5,
   GSK_DEBUG_FALLBACK              = 1 <<  6,
   GSK_DEBUG_GLYPH_CACHE           = 1 <<  7,
+  GSK_DEBUG_PATHS                 = 1 <<  8,
   /* flags below may affect behavior */
   GSK_DEBUG_GEOMETRY              = 1 <<  9,
   GSK_DEBUG_FULL_REDRAW           = 1 << 10,

gsk/gskenums.h

@@ -1,5 +1,5 @@
 /* GSK - The GTK Scene Kit
- * Copyright 2016  Endless 
+ * Copyright 2016  Endless
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -50,7 +50,7 @@
  * @GSK_BLUR_NODE: A node that applies a blur
  * @GSK_DEBUG_NODE: Debug information that does not affect the rendering
  * @GSK_GL_SHADER_NODE: A node that uses OpenGL fragment shaders to render
- 
+
  * The type of a node determines what the node is rendering.
  */
 typedef enum {
@@ -73,6 +73,8 @@ typedef enum {
   GSK_REPEAT_NODE,
   GSK_CLIP_NODE,
   GSK_ROUNDED_CLIP_NODE,
+  GSK_FILL_NODE,
+  GSK_STROKE_NODE,
   GSK_SHADOW_NODE,
   GSK_BLEND_NODE,
   GSK_CROSS_FADE_NODE,
@@ -167,6 +169,107 @@ typedef enum {
   GSK_CORNER_BOTTOM_LEFT
 } GskCorner;
 
+/**
+ * GskFillRule:
+ * @GSK_FILL_RULE_WINDING: If the path crosses the ray from
+ *   left-to-right, counts +1. If the path crosses the ray
+ *   from right to left, counts -1. (Left and right are determined
+ *   from the perspective of looking along the ray from the starting
+ *   point.) If the total count is non-zero, the point will be filled.
+ * @GSK_FILL_RULE_EVEN_ODD: Counts the total number of
+ *   intersections, without regard to the orientation of the contour. If
+ *   the total number of intersections is odd, the point will be
+ *   filled.
+ *
+ * #GskFillRule is used to select how paths are filled, for example in
+ * gsk_fill_node_new(). Whether or not a point is included in the fill is
+ * determined by taking a ray from that point to infinity and looking
+ * at intersections with the path. The ray can be in any direction,
+ * as long as it doesn't pass through the end point of a segment
+ * or have a tricky intersection such as intersecting tangent to the path.
+ * (Note that filling is not actually implemented in this way. This
+ * is just a description of the rule that is applied.)
+ *
+ * New entries may be added in future versions.
+ **/
+typedef enum {
+  GSK_FILL_RULE_WINDING,
+  GSK_FILL_RULE_EVEN_ODD
+} GskFillRule;
+
+/**
+ * GskLineCap:
+ * @GSK_LINE_CAP_BUTT: Start and stop the line exactly at the start
+ *   and end point
+ * @GSK_LINE_CAP_ROUND: Use a round ending, the center of the circle
+ *   is the start or end point.
+ * @GSK_LINE_CAP_SQUARE: use squared ending, the center of the square
+ *   is the start or end point.
+ *
+ * Specifies how to render the start and end points of contours or
+ * dashes when stroking.
+ *
+ * The default line cap style is @GSK_LINE_CAP_BUTT.
+ */
+typedef enum {
+  GSK_LINE_CAP_BUTT,
+  GSK_LINE_CAP_ROUND,
+  GSK_LINE_CAP_SQUARE
+} GskLineCap;
+
+/**
+ * GskLineJoin:
+ * @GSK_LINE_JOIN_MITER: Use a sharp, angled corner
+ * @GSK_LINE_JOIN_MITER_CLIP: Use a sharp, angled corner, at a distance
+ * @GSK_LINE_JOIN_ROUND: Use a round join, the center of the circle is
+ *   the joint point
+ * @GSK_LINE_JOIN_BEVEL: use a cut-off join, the join is cut off at half
+ *   the line width from the joint point
+ * @GSK_LINE_JOIN_ARCS: Use a sharp angled corner made from circles
+ *
+ * Specifies how to render the junction of two lines when stroking.
+ *
+ * See [method@Gsk.Stroke.set_miter_limit] for details on the difference
+ * between @GSK_LINE_JOIN_MITER and @GSK_LINE_JOIN_MITER_CLIP.
+ *
+ * The default line join style is @GSK_LINE_JOIN_MITER.
+ **/
+typedef enum {
+  GSK_LINE_JOIN_MITER,
+  GSK_LINE_JOIN_MITER_CLIP,
+  GSK_LINE_JOIN_ROUND,
+  GSK_LINE_JOIN_BEVEL,
+  GSK_LINE_JOIN_ARCS
+} GskLineJoin;
+
+/**
+ * GskPathOperation:
+ * @GSK_PATH_MOVE: A move-to operation, with 1 point describing the
+ *   target point.
+ * @GSK_PATH_LINE: A line-to operation, with 2 points describing the
+ *   start and end point of a straight line.
+ * @GSK_PATH_CLOSE: A close operation ending the current contour with
+ *   a line back to the starting point. Two points describe the start
+ *   and end of the line.
+ * @GSK_PATH_CURVE: A curve-to operation describing a cubic Bézier curve
+ *   with 4 points describing the start point, the two control points
+ *   and the end point of the curve.
+ * @GSK_PATH_CONIC: A weighted quadratic Bézier curve with 3 points
+ *   describing the start point, control point and end point of the
+ *   curve. A weight for the curve will be passed, too.
+ *
+ * Path operations can be used to approximate a #GskPath.
+ *
+ * More values may be added in the future.
+ **/
+typedef enum {
+  GSK_PATH_MOVE,
+  GSK_PATH_CLOSE,
+  GSK_PATH_LINE,
+  GSK_PATH_CURVE,
+  GSK_PATH_CONIC,
+} GskPathOperation;
+
 /**
  * GskSerializationError:
  * @GSK_SERIALIZATION_UNSUPPORTED_FORMAT: The format can not be identified
@@ -251,5 +354,4 @@ typedef enum
   GSK_GL_UNIFORM_TYPE_VEC4,
 } GskGLUniformType;
 
-
 #endif /* __GSK_TYPES_H__ */

gsk/gskpath.h

@@ -0,0 +1,154 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#ifndef __GSK_PATH_H__
+#define __GSK_PATH_H__
+
+#if !defined (__GSK_H_INSIDE__) && !defined (GTK_COMPILATION)
+#error "Only <gsk/gsk.h> can be included directly."
+#endif
+
+
+#include <gsk/gsktypes.h>
+
+G_BEGIN_DECLS
+
+/**
+ * GskPathForeachFlags:
+ * @GSK_PATH_FOREACH_ALLOW_CURVE: Allow emission of `GSK_PATH_CURVE` operations.
+ * @GSK_PATH_FOREACH_ALLOW_CONIC: Allow emission of `GSK_PATH_CONIC` operations.
+ *
+ * Flags that can be passed to [method@Gsk.Path.foreach] to enable additional
+ * features.
+ *
+ * By default, [method@Gsk.Path.foreach] will only emit a path with all
+ * operations flattened to straight lines to allow for maximum compatibility.
+ * The only operations emitted will be `GSK_PATH_MOVE`, `GSK_PATH_LINE` and
+ * `GSK_PATH_CLOSE`.
+ */
+typedef enum
+{
+  GSK_PATH_FOREACH_ALLOW_CURVE = (1 << 0),
+  GSK_PATH_FOREACH_ALLOW_CONIC = (1 << 1)
+} GskPathForeachFlags;
+
+/**
+ * GskPathForeachFunc:
+ * @op: The operation to perform
+ * @pts: The points of the operation
+ * @n_pts: The number of points
+ * @weight: The weight for conic curves, or unused if not a conic curve.
+ * @user_data: The user data provided with the function
+ *
+ * Prototype of the callback to iterate throught the operations of
+ * a path.
+ *
+ * Returns: %TRUE to continue evaluating the path, %FALSE to
+ *   immediately abort and not call the function again.
+ */
+typedef gboolean (* GskPathForeachFunc) (GskPathOperation        op,
+                                         const graphene_point_t *pts,
+                                         gsize                   n_pts,
+                                         float                   weight,
+                                         gpointer                user_data);
+
+#define GSK_TYPE_PATH (gsk_path_get_type ())
+
+GDK_AVAILABLE_IN_ALL
+GType                   gsk_path_get_type                       (void) G_GNUC_CONST;
+GDK_AVAILABLE_IN_ALL
+GskPath *               gsk_path_new_from_cairo                 (const cairo_path_t     *path);
+
+GDK_AVAILABLE_IN_ALL
+GskPath *               gsk_path_ref                            (GskPath                *self);
+GDK_AVAILABLE_IN_ALL
+void                    gsk_path_unref                          (GskPath                *self);
+
+GDK_AVAILABLE_IN_ALL
+void                    gsk_path_print                          (GskPath                *self,
+                                                                 GString                *string);
+GDK_AVAILABLE_IN_ALL
+char *                  gsk_path_to_string                      (GskPath                *self);
+
+GDK_AVAILABLE_IN_ALL
+GskPath *               gsk_path_parse                          (const char             *string);
+
+GDK_AVAILABLE_IN_ALL
+void                    gsk_path_to_cairo                       (GskPath                *self,
+                                                                 cairo_t                *cr);
+
+GDK_AVAILABLE_IN_ALL
+gboolean                gsk_path_is_empty                       (GskPath                *self);
+GDK_AVAILABLE_IN_ALL
+gboolean                gsk_path_get_bounds                     (GskPath                *self,
+                                                                 graphene_rect_t        *bounds);
+GDK_AVAILABLE_IN_ALL
+gboolean                gsk_path_get_stroke_bounds              (GskPath                *path,
+                                                                 const GskStroke        *stroke,
+                                                                 graphene_rect_t        *bounds);
+
+GDK_AVAILABLE_IN_ALL
+gboolean                gsk_path_is_convex                      (GskPath                *self);
+
+GDK_AVAILABLE_IN_ALL
+gboolean                gsk_path_foreach                        (GskPath                *self,
+                                                                 GskPathForeachFlags     flags,
+                                                                 GskPathForeachFunc      func,
+                                                                 gpointer                user_data);
+
+GDK_AVAILABLE_IN_ALL
+GskPath *               gsk_path_reverse                        (GskPath                *self);
+
+GDK_AVAILABLE_IN_ALL
+GskPath *               gsk_path_transform                      (GskPath                *self,
+                                                                 GskTransform           *transform);
+
+GDK_AVAILABLE_IN_ALL
+GskPath *               gsk_path_stroke                         (GskPath                *self,
+                                                                 GskStroke              *stroke);
+
+GDK_AVAILABLE_IN_ALL
+GskPath *               gsk_path_offset                         (GskPath                *self,
+                                                                 float                   distance,
+                                                                 GskLineJoin             line_join,
+                                                                 float                   miter_limit);
+
+GDK_AVAILABLE_IN_ALL
+GskPath *               gsk_path_union                          (GskPath                *first,
+                                                                 GskPath                *second);
+
+GDK_AVAILABLE_IN_ALL
+GskPath *               gsk_path_intersection                   (GskPath                *first,
+                                                                 GskPath                *second);
+
+GDK_AVAILABLE_IN_ALL
+GskPath *               gsk_path_difference                     (GskPath                *first,
+                                                                 GskPath                *second);
+
+GDK_AVAILABLE_IN_ALL
+GskPath *               gsk_path_symmetric_difference           (GskPath                *first,
+                                                                 GskPath                *second);
+
+GDK_AVAILABLE_IN_ALL
+GskPath *               gsk_path_simplify                       (GskPath                *self);
+
+
+G_END_DECLS
+
+#endif /* __GSK_PATH_H__ */

gsk/gskpathbuilder.c

@@ -0,0 +1,964 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#include "config.h"
+
+#include "gskpathbuilder.h"
+
+#include "gskpathprivate.h"
+
+/**
+ * GskPathBuilder:
+ *
+ * A `GskPathBuilder` is an auxiliary object that is used to
+ * create new `GskPath` objects.
+ *
+ * A path is constructed like this:
+ *
+ * ```
+ * GskPath *
+ * construct_path (void)
+ * {
+ *   GskPathBuilder *builder;
+ *
+ *   builder = gsk_path_builder_new ();
+ *
+ *   // add contours to the path here
+ *
+ *   return gsk_path_builder_free_to_path (builder);
+ * }
+ * ```
+ *
+ * Adding contours to the path can be done in two ways.
+ * The easiest option is to use the `gsk_path_builder_add_*` group
+ * of functions that add predefined contours to the current path,
+ * either common shapes like [method@Gsk.PathBuilder.add_circle]
+ * or by adding from other paths like [method@Gsk.PathBuilder.add_path].
+ *
+ * The other option is to define each line and curve manually with
+ * the `gsk_path_builder_*_to` group of functions. You start with
+ * a call to [method@Gsk.PathBuilder.move_to] to set the starting point
+ * and then use multiple calls to any of the drawing functions to
+ * move the pen along the plane. Once you are done, you can call
+ * [method@Gsk.PathBuilder.close] to close the path by connecting it
+ * back with a line to the starting point.
+ * This is similar for how paths are drawn in Cairo.
+ */
+
+struct _GskPathBuilder
+{
+  int ref_count;
+
+  GSList *contours; /* (reverse) list of already recorded contours */
+
+  GskPathFlags flags; /* flags for the current path */
+  graphene_point_t current_point; /* the point all drawing ops start from */
+  GArray *ops; /* operations for current contour - size == 0 means no current contour */
+  GArray *points; /* points for the operations */
+};
+
+G_DEFINE_BOXED_TYPE (GskPathBuilder,
+                     gsk_path_builder,
+                     gsk_path_builder_ref,
+                     gsk_path_builder_unref)
+
+
+/**
+ * gsk_path_builder_new:
+ *
+ * Create a new `GskPathBuilder` object. The resulting builder
+ * would create an empty `GskPath`. Use addition functions to add
+ * types to it.
+ *
+ * Returns: a new `GskPathBuilder`
+ **/
+GskPathBuilder *
+gsk_path_builder_new (void)
+{
+  GskPathBuilder *builder;
+
+  builder = g_slice_new0 (GskPathBuilder);
+  builder->ref_count = 1;
+
+  builder->ops = g_array_new (FALSE, FALSE, sizeof (gskpathop));
+  builder->points = g_array_new (FALSE, FALSE, sizeof (graphene_point_t));
+
+  /* Be explicit here */
+  builder->current_point = GRAPHENE_POINT_INIT (0, 0);
+
+  return builder;
+}
+
+/**
+ * gsk_path_builder_ref:
+ * @builder: a `GskPathBuilder`
+ *
+ * Acquires a reference on the given @builder.
+ *
+ * This function is intended primarily for bindings. `GskPathBuilder` objects
+ * should not be kept around.
+ *
+ * Returns: (transfer none): the given `GskPathBuilder` with
+ *   its reference count increased
+ */
+GskPathBuilder *
+gsk_path_builder_ref (GskPathBuilder *builder)
+{
+  g_return_val_if_fail (builder != NULL, NULL);
+  g_return_val_if_fail (builder->ref_count > 0, NULL);
+
+  builder->ref_count += 1;
+
+  return builder;
+}
+
+/* We're cheating here. Out pathops are relative to the NULL pointer,
+ * so that we can not care about the points GArray reallocating itself
+ * until we create the contour.
+ * This does however mean that we need to not use gsk_pathop_get_points()
+ * without offsetting the returned pointer.
+ */
+static inline gskpathop
+gsk_pathop_encode_index (GskPathOperation op,
+                         gsize            index)
+{
+  return gsk_pathop_encode (op, ((graphene_point_t *) NULL) + index);
+}
+
+static void
+gsk_path_builder_ensure_current (GskPathBuilder *builder)
+{
+  if (builder->ops->len != 0)
+    return;
+
+  builder->flags = GSK_PATH_FLAT;
+  g_array_append_vals (builder->ops, (gskpathop[1]) { gsk_pathop_encode_index (GSK_PATH_MOVE, 0) }, 1);
+  g_array_append_val (builder->points, builder->current_point);
+}
+
+static void
+gsk_path_builder_append_current (GskPathBuilder         *builder,
+                                 GskPathOperation        op,
+                                 gsize                   n_points,
+                                 const graphene_point_t *points)
+{
+  gsk_path_builder_ensure_current (builder);
+
+  g_array_append_vals (builder->ops, (gskpathop[1]) { gsk_pathop_encode_index (op, builder->points->len - 1) }, 1);
+  g_array_append_vals (builder->points, points, n_points);
+
+  builder->current_point = points[n_points - 1];
+}
+
+static void
+gsk_path_builder_end_current (GskPathBuilder *builder)
+{
+  GskContour *contour;
+
+  if (builder->ops->len == 0)
+   return;
+
+  contour = gsk_standard_contour_new (builder->flags,
+                                      (graphene_point_t *) builder->points->data,
+                                      builder->points->len,
+                                      (gskpathop *) builder->ops->data,
+                                      builder->ops->len,
+                                      (graphene_point_t *) builder->points->data - (graphene_point_t *) NULL);
+
+  g_array_set_size (builder->ops, 0);
+  g_array_set_size (builder->points, 0);
+
+  /* do this at the end to avoid inflooping when add_contour calls back here */
+  gsk_path_builder_add_contour (builder, contour);
+}
+
+static void
+gsk_path_builder_clear (GskPathBuilder *builder)
+{
+  gsk_path_builder_end_current (builder);
+
+  g_slist_free_full (builder->contours, g_free);
+  builder->contours = NULL;
+}
+
+/**
+ * gsk_path_builder_unref:
+ * @builder: a `GskPathBuilder`
+ *
+ * Releases a reference on the given @builder.
+ */
+void
+gsk_path_builder_unref (GskPathBuilder *builder)
+{
+  g_return_if_fail (builder != NULL);
+  g_return_if_fail (builder->ref_count > 0);
+
+  builder->ref_count -= 1;
+
+  if (builder->ref_count > 0)
+    return;
+
+  gsk_path_builder_clear (builder);
+  g_array_unref (builder->ops);
+  g_array_unref (builder->points);
+  g_slice_free (GskPathBuilder, builder);
+}
+
+/**
+ * gsk_path_builder_free_to_path: (skip)
+ * @builder: a `GskPathBuilder`
+ *
+ * Creates a new `GskPath` from the current state of the
+ * given @builder, and frees the @builder instance.
+ *
+ * Returns: (transfer full): the newly created `GskPath`
+ *   with all the contours added to @builder
+ */
+GskPath *
+gsk_path_builder_free_to_path (GskPathBuilder *builder)
+{
+  GskPath *res;
+
+  g_return_val_if_fail (builder != NULL, NULL);
+
+  res = gsk_path_builder_to_path (builder);
+
+  gsk_path_builder_unref (builder);
+
+  return res;
+}
+
+/**
+ * gsk_path_builder_to_path:
+ * @builder: a `GskPathBuilder`
+ *
+ * Creates a new `GskPath` from the given @builder.
+ *
+ * The given `GskPathBuilder` is reset once this function returns;
+ * you cannot call this function multiple times on the same @builder instance.
+ *
+ * This function is intended primarily for bindings. C code should use
+ * gsk_path_builder_free_to_path().
+ *
+ * Returns: (transfer full): the newly created `GskPath`
+ *   with all the contours added to @builder
+ */
+GskPath *
+gsk_path_builder_to_path (GskPathBuilder *builder)
+{
+  GskPath *path;
+
+  g_return_val_if_fail (builder != NULL, NULL);
+
+  gsk_path_builder_end_current (builder);
+
+  builder->contours = g_slist_reverse (builder->contours);
+
+  path = gsk_path_new_from_contours (builder->contours);
+
+  gsk_path_builder_clear (builder);
+
+  return path;
+}
+
+void
+gsk_path_builder_add_contour (GskPathBuilder *builder,
+                              GskContour     *contour)
+{
+  gsk_path_builder_end_current (builder);
+
+  builder->contours = g_slist_prepend (builder->contours, contour);
+}
+
+/**
+ * gsk_path_builder_get_current_point:
+ * @builder: a #GskPathBuilder
+ *
+ * Gets the current point. The current point is used for relative
+ * drawing commands and updated after every operation.
+ *
+ * When @builder is created, the default current point is set to (0, 0).
+ *
+ * Returns: (transfer none): The current point
+ **/
+const graphene_point_t *
+gsk_path_builder_get_current_point (GskPathBuilder *builder)
+{
+  g_return_val_if_fail (builder != NULL, NULL);
+
+  return &builder->current_point;
+}
+
+/**
+ * gsk_path_builder_add_path:
+ * @builder: a `GskPathBuilder`
+ * @path: (transfer none): the path to append
+ *
+ * Appends all of @path to @builder.
+ **/
+void
+gsk_path_builder_add_path (GskPathBuilder *builder,
+                           GskPath        *path)
+{
+  gsize i;
+
+  g_return_if_fail (builder != NULL);
+  g_return_if_fail (path != NULL);
+
+  for (i = 0; i < gsk_path_get_n_contours (path); i++)
+    {
+      const GskContour *contour = gsk_path_get_contour (path, i);
+
+      gsk_path_builder_add_contour (builder, gsk_contour_dup (contour));
+    }
+}
+
+/**
+ * gsk_path_builder_add_rect:
+ * @builder: A `GskPathBuilder`
+ * @rect: The rectangle to add to @builder
+ *
+ * Adds a path representing the given rectangle.
+ *
+ * If the width or height of the rectangle is negative, the start
+ * point will be on the right or bottom, respectively.
+ *
+ * If the the width or height are 0, the path will be a closed
+ * horizontal or vertical line. If both are 0, it'll be a closed dot.
+ **/
+void
+gsk_path_builder_add_rect (GskPathBuilder        *builder,
+                           const graphene_rect_t *rect)
+{
+  GskContour *contour;
+
+  g_return_if_fail (builder != NULL);
+
+  contour = gsk_rect_contour_new (rect);
+  gsk_path_builder_add_contour (builder, contour);
+
+  gsk_contour_get_start_end (contour, NULL, &builder->current_point);
+}
+
+/**
+ * gsk_path_builder_add_rounded_rect:
+ * @builder: a `GskPathBuilder`
+ * @rect: the rounded rect
+ *
+ * Adds @rect as a new contour to the path built in @builder.
+ **/
+void
+gsk_path_builder_add_rounded_rect (GskPathBuilder       *builder,
+                                   const GskRoundedRect *rect)
+{
+  const float weight = sqrt(0.5f);
+
+  g_return_if_fail (builder != NULL);
+  g_return_if_fail (rect != NULL);
+
+  gsk_path_builder_move_to (builder,
+                            rect->bounds.origin.x + rect->corner[GSK_CORNER_TOP_LEFT].width,
+                            rect->bounds.origin.y);
+  /* top */
+  gsk_path_builder_line_to (builder,
+                            rect->bounds.origin.x + rect->bounds.size.width - rect->corner[GSK_CORNER_TOP_RIGHT].width,
+                            rect->bounds.origin.y);
+  /* topright corner */
+  gsk_path_builder_conic_to (builder,
+                             rect->bounds.origin.x + rect->bounds.size.width,
+                             rect->bounds.origin.y,
+                             rect->bounds.origin.x + rect->bounds.size.width,
+                             rect->bounds.origin.y + rect->corner[GSK_CORNER_TOP_RIGHT].height,
+                             weight);
+  /* right */
+  gsk_path_builder_line_to (builder,
+                            rect->bounds.origin.x + rect->bounds.size.width,
+                            rect->bounds.origin.y + rect->bounds.size.height - rect->corner[GSK_CORNER_BOTTOM_RIGHT].height);
+  /* bottomright corner */
+  gsk_path_builder_conic_to (builder,
+                             rect->bounds.origin.x + rect->bounds.size.width,
+                             rect->bounds.origin.y + rect->bounds.size.height,
+                             rect->bounds.origin.x + rect->bounds.size.width - rect->corner[GSK_CORNER_BOTTOM_RIGHT].width,
+                             rect->bounds.origin.y + rect->bounds.size.height,
+                             weight);
+  /* bottom */
+  gsk_path_builder_line_to (builder,
+                            rect->bounds.origin.x + rect->corner[GSK_CORNER_BOTTOM_LEFT].width,
+                            rect->bounds.origin.y + rect->bounds.size.height);
+  /* bottomleft corner */
+  gsk_path_builder_conic_to (builder,
+                             rect->bounds.origin.x,
+                             rect->bounds.origin.y + rect->bounds.size.height,
+                             rect->bounds.origin.x,
+                             rect->bounds.origin.y + rect->bounds.size.height - rect->corner[GSK_CORNER_BOTTOM_LEFT].height,
+                             weight);
+  /* left */
+  gsk_path_builder_line_to (builder,
+                            rect->bounds.origin.x,
+                            rect->bounds.origin.y + rect->corner[GSK_CORNER_TOP_LEFT].height);
+  /* topleft corner */
+  gsk_path_builder_conic_to (builder,
+                             rect->bounds.origin.x,
+                             rect->bounds.origin.y,
+                             rect->bounds.origin.x + rect->corner[GSK_CORNER_TOP_LEFT].width,
+                             rect->bounds.origin.y,
+                             weight);
+  /* done */
+  gsk_path_builder_close (builder);
+}
+
+/**
+ * gsk_path_builder_add_circle:
+ * @builder: a `GskPathBuilder`
+ * @center: the center of the circle
+ * @radius: the radius of the circle
+ *
+ * Adds a circle with the @center and @radius.
+ **/
+void
+gsk_path_builder_add_circle (GskPathBuilder         *builder,
+                             const graphene_point_t *center,
+                             float                   radius)
+{
+  GskContour *contour;
+
+  g_return_if_fail (builder != NULL);
+  g_return_if_fail (center != NULL);
+  g_return_if_fail (radius > 0);
+
+  contour = gsk_circle_contour_new (center, radius, 0, 360);
+  gsk_path_builder_add_contour (builder, contour);
+}
+
+/**
+ * gsk_path_builder_add_ellipse:
+ * @builder: a `GskPathBuilder`
+ * @center: the center point of the ellipse
+ * @radius: the radius of the ellipse in x/y direction
+ *
+ * Adds an ellipse with the given @center and the @radius in
+ * x/y direction.
+ **/
+void
+gsk_path_builder_add_ellipse (GskPathBuilder         *builder,
+                              const graphene_point_t *center,
+                              const graphene_size_t  *radius)
+{
+  const float weight = sqrt(0.5f);
+  graphene_point_t pts[8];
+
+  g_return_if_fail (builder != NULL);
+  g_return_if_fail (center != NULL);
+  g_return_if_fail (radius != NULL);
+
+  pts[0] = GRAPHENE_POINT_INIT (center->x + radius->width / 2,
+                                center->y);
+  pts[1] = GRAPHENE_POINT_INIT (center->x + radius->width / 2,
+                                center->y + radius->height / 2);
+  pts[2] = GRAPHENE_POINT_INIT (center->x,
+                                center->y + radius->height / 2);
+  pts[3] = GRAPHENE_POINT_INIT (center->x - radius->width / 2,
+                                center->y + radius->height / 2);
+  pts[4] = GRAPHENE_POINT_INIT (center->x - radius->width / 2,
+                                center->y);
+  pts[5] = GRAPHENE_POINT_INIT (center->x - radius->width / 2,
+                                center->y - radius->height / 2);
+  pts[6] = GRAPHENE_POINT_INIT (center->x,
+                                center->y - radius->height / 2);
+  pts[7] = GRAPHENE_POINT_INIT (center->x + radius->width / 2,
+                                center->y - radius->height / 2);
+
+  gsk_path_builder_move_to (builder, pts[0].x, pts[0].y);
+  gsk_path_builder_conic_to (builder, pts[1].x, pts[1].y, pts[2].x, pts[2].y, weight);
+  gsk_path_builder_conic_to (builder, pts[3].x, pts[3].y, pts[4].x, pts[4].y, weight);
+  gsk_path_builder_conic_to (builder, pts[5].x, pts[5].y, pts[6].x, pts[6].y, weight);
+  gsk_path_builder_conic_to (builder, pts[7].x, pts[7].y, pts[0].x, pts[0].y, weight);
+  gsk_path_builder_close (builder);
+}
+
+/**
+ * gsk_path_builder_move_to:
+ * @builder: a `GskPathBuilder`
+ * @x: x coordinate
+ * @y: y coordinate
+ *
+ * Starts a new contour by placing the pen at @x, @y.
+ *
+ * If `gsk_path_builder_move_to()` is called twice in succession,
+ * the first call will result in a contour made up of a single point.
+ * The second call will start a new contour.
+ **/
+void
+gsk_path_builder_move_to (GskPathBuilder *builder,
+                          float           x,
+                          float           y)
+{
+  g_return_if_fail (builder != NULL);
+
+  gsk_path_builder_end_current (builder);
+
+  builder->current_point = GRAPHENE_POINT_INIT(x, y);
+
+  gsk_path_builder_ensure_current (builder);
+}
+
+/**
+ * gsk_path_builder_rel_move_to:
+ * @builder: a `GskPathBuilder`
+ * @x: x offset
+ * @y: y offset
+ *
+ * Starts a new contour by placing the pen at @x, @y relative to the current
+ * point.
+ *
+ * This is the relative version of [method@Gsk.PathBuilder.move_to].
+ **/
+void
+gsk_path_builder_rel_move_to (GskPathBuilder *builder,
+                              float           x,
+                              float           y)
+{
+  g_return_if_fail (builder != NULL);
+
+  gsk_path_builder_move_to (builder,
+                            builder->current_point.x + x,
+                            builder->current_point.y + y);
+}
+
+/**
+ * gsk_path_builder_line_to:
+ * @builder: a `GskPathBuilder`
+ * @x: x coordinate
+ * @y: y coordinate
+ *
+ * Draws a line from the current point to @x, @y and makes it the new current
+ * point.
+ **/
+void
+gsk_path_builder_line_to (GskPathBuilder *builder,
+                          float           x,
+                          float           y)
+{
+  g_return_if_fail (builder != NULL);
+
+  /* skip the line if it goes to the same point */
+  if (graphene_point_equal (&builder->current_point,
+                            &GRAPHENE_POINT_INIT (x, y)))
+    return;
+
+  gsk_path_builder_append_current (builder,
+                                   GSK_PATH_LINE,
+                                   1, (graphene_point_t[1]) {
+                                     GRAPHENE_POINT_INIT (x, y)
+                                   });
+}
+
+/**
+ * gsk_path_builder_rel_line_to:
+ * @builder: a `GskPathBuilder`
+ * @x: x offset
+ * @y: y offset
+ *
+ * Draws a line from the current point to a point offset to it by @x, @y
+ * and makes it the new current point.
+ *
+ * This is the relative version of [method@Gsk.PathBuilder.line_to].
+ **/
+void
+gsk_path_builder_rel_line_to (GskPathBuilder *builder,
+                              float           x,
+                              float           y)
+{
+  g_return_if_fail (builder != NULL);
+
+  gsk_path_builder_line_to (builder,
+                            builder->current_point.x + x,
+                            builder->current_point.y + y);
+}
+
+/**
+ * gsk_path_builder_curve_to:
+ * @builder: a `GskPathBuilder`
+ * @x1: x coordinate of first control point
+ * @y1: y coordinate of first control point
+ * @x2: x coordinate of second control point
+ * @y2: y coordinate of second control point
+ * @x3: x coordinate of the end of the curve
+ * @y3: y coordinate of the end of the curve
+ *
+ * Adds a [cubic Bézier curve](https://en.wikipedia.org/wiki/B%C3%A9zier_curve)
+ * from the current point to @x3, @y3 with @x1, @y1 and @x2, @y2 as the control
+ * points.
+ *
+ * After this, @x3, @y3 will be the new current point.
+ **/
+void
+gsk_path_builder_curve_to (GskPathBuilder *builder,
+                           float           x1,
+                           float           y1,
+                           float           x2,
+                           float           y2,
+                           float           x3,
+                           float           y3)
+{
+  g_return_if_fail (builder != NULL);
+
+  builder->flags &= ~GSK_PATH_FLAT;
+  gsk_path_builder_append_current (builder,
+                                   GSK_PATH_CURVE,
+                                   3, (graphene_point_t[3]) {
+                                     GRAPHENE_POINT_INIT (x1, y1),
+                                     GRAPHENE_POINT_INIT (x2, y2),
+                                     GRAPHENE_POINT_INIT (x3, y3)
+                                   });
+}
+
+/**
+ * gsk_path_builder_rel_curve_to:
+ * @builder: a `GskPathBuilder`
+ * @x1: x offset of first control point
+ * @y1: y offset of first control point
+ * @x2: x offset of second control point
+ * @y2: y offset of second control point
+ * @x3: x offset of the end of the curve
+ * @y3: y offset of the end of the curve
+ *
+ * Adds a [cubic Bézier curve](https://en.wikipedia.org/wiki/B%C3%A9zier_curve)
+ * from the current point to @x3, @y3 with @x1, @y1 and @x2, @y2 as the control
+ * points. All coordinates are given relative to the current point.
+ *
+ * This is the relative version of [method@Gsk.PathBuilder.curve_to].
+ **/
+void
+gsk_path_builder_rel_curve_to (GskPathBuilder *builder,
+                               float           x1,
+                               float           y1,
+                               float           x2,
+                               float           y2,
+                               float           x3,
+                               float           y3)
+{
+  g_return_if_fail (builder != NULL);
+
+  gsk_path_builder_curve_to (builder,
+                             builder->current_point.x + x1,
+                             builder->current_point.y + y1,
+                             builder->current_point.x + x2,
+                             builder->current_point.y + y2,
+                             builder->current_point.x + x3,
+                             builder->current_point.y + y3);
+}
+
+/**
+ * gsk_path_builder_conic_to:
+ * @builder: a `GskPathBuilder`
+ * @x1: x coordinate of control point
+ * @y1: y coordinate of control point
+ * @x2: x coordinate of the end of the curve
+ * @y2: y coordinate of the end of the curve
+ * @weight: weight of the curve
+ *
+ * Adds a [conic curve](https://en.wikipedia.org/wiki/Non-uniform_rational_B-spline)
+ * from the current point to @x2, @y2 with the given
+ * @weight and @x1, @y1 as the single control point.
+ *
+ * Conic curves can be used to draw ellipses and circles.
+ *
+ * After this, @x2, @y2 will be the new current point.
+ **/
+void
+gsk_path_builder_conic_to (GskPathBuilder *builder,
+                           float           x1,
+                           float           y1,
+                           float           x2,
+                           float           y2,
+                           float           weight)
+{
+  g_return_if_fail (builder != NULL);
+  g_return_if_fail (weight >= 0);
+
+  builder->flags &= ~GSK_PATH_FLAT;
+  gsk_path_builder_append_current (builder,
+                                   GSK_PATH_CONIC,
+                                   3, (graphene_point_t[3]) {
+                                     GRAPHENE_POINT_INIT (x1, y1),
+                                     GRAPHENE_POINT_INIT (weight, 0),
+                                     GRAPHENE_POINT_INIT (x2, y2)
+                                   });
+}
+
+/**
+ * gsk_path_builder_rel_conic_to:
+ * @builder: a `GskPathBuilder`
+ * @x1: x offset of control point
+ * @y1: y offset of control point
+ * @x2: x offset of the end of the curve
+ * @y2: y offset of the end of the curve
+ * @weight: weight of the curve
+ *
+ * Adds a [conic curve](https://en.wikipedia.org/wiki/Non-uniform_rational_B-spline)
+ * from the current point to @x2, @y2 with the given
+ * @weight and @x1, @y1 as the single control point.
+ *
+ * This is the relative version of [method@Gsk.PathBuilder.conic_to].
+ **/
+void
+gsk_path_builder_rel_conic_to (GskPathBuilder *builder,
+                               float           x1,
+                               float           y1,
+                               float           x2,
+                               float           y2,
+                               float           weight)
+{
+  g_return_if_fail (builder != NULL);
+  g_return_if_fail (weight >= 0);
+
+  gsk_path_builder_conic_to (builder,
+                             builder->current_point.x + x1,
+                             builder->current_point.y + y1,
+                             builder->current_point.x + x2,
+                             builder->current_point.y + y2,
+                             weight);
+}
+
+/**
+ * gsk_path_builder_close:
+ * @builder: a `GskPathBuilder`
+ *
+ * Ends the current contour with a line back to the start point.
+ *
+ * Note that this is different from calling [method@Gsk.PathBuilder.line_to]
+ * with the start point in that the contour will be closed. A closed
+ * contour behaves different from an open one when stroking its start
+ * and end point are considered connected, so they will be joined
+ * via the line join, and not ended with line caps.
+ **/
+void
+gsk_path_builder_close (GskPathBuilder *builder)
+{
+  g_return_if_fail (builder != NULL);
+
+  if (builder->ops->len == 0)
+    return;
+
+  builder->flags |= GSK_PATH_CLOSED;
+  gsk_path_builder_append_current (builder,
+                                   GSK_PATH_CLOSE,
+                                   1, (graphene_point_t[1]) {
+                                     g_array_index (builder->points, graphene_point_t, 0)
+                                   });
+
+  gsk_path_builder_end_current (builder);
+}
+
+
+static void
+arc_segment (GskPathBuilder *builder,
+             double          cx,
+             double          cy,
+             double          rx,
+             double          ry,
+             double          sin_phi,
+             double          cos_phi,
+             double          sin_th0,
+             double          cos_th0,
+             double          sin_th1,
+             double          cos_th1,
+             double          t)
+{
+  double x1, y1, x2, y2, x3, y3;
+
+  x1 = rx * (cos_th0 - t * sin_th0);
+  y1 = ry * (sin_th0 + t * cos_th0);
+  x3 = rx * cos_th1;
+  y3 = ry * sin_th1;
+  x2 = x3 + rx * (t * sin_th1);
+  y2 = y3 + ry * (-t * cos_th1);
+
+  gsk_path_builder_curve_to (builder,
+                             cx + cos_phi * x1 - sin_phi * y1,
+                             cy + sin_phi * x1 + cos_phi * y1,
+                             cx + cos_phi * x2 - sin_phi * y2,
+                             cy + sin_phi * x2 + cos_phi * y2,
+                             cx + cos_phi * x3 - sin_phi * y3,
+                             cy + sin_phi * x3 + cos_phi * y3);
+}
+
+void
+gsk_path_builder_svg_arc_to (GskPathBuilder *builder,
+                             float           rx,
+                             float           ry,
+                             float           x_axis_rotation,
+                             gboolean        large_arc,
+                             gboolean        positive_sweep,
+                             float           x,
+                             float           y)
+{
+  graphene_point_t *current;
+  double x1, y1, x2, y2;
+  double phi, sin_phi, cos_phi;
+  double mid_x, mid_y;
+  double lambda;
+  double d;
+  double k;
+  double x1_, y1_;
+  double cx_, cy_;
+  double  cx, cy;
+  double ux, uy, u_len;
+  double cos_theta1, theta1;
+  double vx, vy, v_len;
+  double dp_uv;
+  double cos_delta_theta, delta_theta;
+  int i, n_segs;
+  double d_theta, theta;
+  double sin_th0, cos_th0;
+  double sin_th1, cos_th1;
+  double th_half;
+  double t;
+
+  if (builder->points->len > 0)
+    {
+      current = &g_array_index (builder->points, graphene_point_t, builder->points->len - 1);
+      x1 = current->x;
+      y1 = current->y;
+    }
+  else
+    {
+      x1 = 0;
+      y1 = 0;
+    }
+  x2 = x;
+  y2 = y;
+
+  phi = x_axis_rotation * M_PI / 180.0;
+  sincos (phi, &sin_phi, &cos_phi);
+
+  rx = fabs (rx);
+  ry = fabs (ry);
+
+  mid_x = (x1 - x2) / 2;
+  mid_y = (y1 - y2) / 2;
+
+  x1_ = cos_phi * mid_x + sin_phi * mid_y;
+  y1_ = - sin_phi * mid_x + cos_phi * mid_y;
+
+  lambda = (x1_ / rx) * (x1_ / rx) + (y1_ / ry) * (y1_ / ry);
+  if (lambda > 1)
+    {
+      lambda = sqrt (lambda);
+      rx *= lambda;
+      ry *= lambda;
+    }
+
+  d = (rx * y1_) * (rx * y1_) + (ry * x1_) * (ry * x1_);
+  if (d == 0)
+    return;
+
+  k = sqrt (fabs ((rx * ry) * (rx * ry) / d - 1.0));
+  if (positive_sweep == large_arc)
+    k = -k;
+
+  cx_ = k * rx * y1_ / ry;
+  cy_ = -k * ry * x1_ / rx;
+
+  cx = cos_phi * cx_ - sin_phi * cy_ + (x1 + x2) / 2;
+  cy = sin_phi * cx_ + cos_phi * cy_ + (y1 + y2) / 2;
+
+  ux = (x1_ - cx_) / rx;
+  uy = (y1_ - cy_) / ry;
+  u_len = sqrt (ux * ux + uy * uy);
+  if (u_len == 0)
+    return;
+
+  cos_theta1 = CLAMP (ux / u_len, -1, 1);
+  theta1 = acos (cos_theta1);
+  if (uy < 0)
+    theta1 = - theta1;
+
+  vx = (- x1_ - cx_) / rx;
+  vy = (- y1_ - cy_) / ry;
+  v_len = sqrt (vx * vx + vy * vy);
+  if (v_len == 0)
+    return;
+
+  dp_uv = ux * vx + uy * vy;
+  cos_delta_theta = CLAMP (dp_uv / (u_len * v_len), -1, 1);
+  delta_theta = acos (cos_delta_theta);
+  if (ux * vy - uy * vx < 0)
+    delta_theta = - delta_theta;
+  if (positive_sweep && delta_theta < 0)
+    delta_theta += 2 * M_PI;
+  else if (!positive_sweep && delta_theta > 0)
+    delta_theta -= 2 * M_PI;
+
+  n_segs = ceil (fabs (delta_theta / (M_PI_2 + 0.001)));
+  d_theta = delta_theta / n_segs;
+  theta = theta1;
+  sincos (theta1, &sin_th1, &cos_th1);
+
+  th_half = d_theta / 2;
+  t = (8.0 / 3.0) * sin (th_half / 2) * sin (th_half / 2) / sin (th_half);
+
+  for (i = 0; i < n_segs; i++)
+    {
+      theta = theta1;
+      theta1 = theta + d_theta;
+      sin_th0 = sin_th1;
+      cos_th0 = cos_th1;
+      sincos (theta1, &sin_th1, &cos_th1);
+      arc_segment (builder,
+                   cx, cy, rx, ry,
+                   sin_phi, cos_phi,
+                   sin_th0, cos_th0,
+                   sin_th1, cos_th1,
+                   t);
+    }
+}
+
+/**
+ * gsk_path_builder_add_layout:
+ * @builder: a `GskPathBuilder`
+ * @layout: the pango layout to add
+ *
+ * Adds the outlines for the glyphs in @layout to @builder.
+ */
+void
+gsk_path_builder_add_layout (GskPathBuilder *builder,
+                             PangoLayout    *layout)
+{
+  cairo_surface_t *surface;
+  cairo_t *cr;
+  cairo_path_t *cairo_path;
+  GskPath *path;
+
+  surface = cairo_recording_surface_create (CAIRO_CONTENT_COLOR_ALPHA, NULL);
+  cr = cairo_create (surface);
+
+  pango_cairo_layout_path (cr, layout);
+  cairo_path = cairo_copy_path_flat (cr);
+  path = gsk_path_new_from_cairo (cairo_path);
+
+  gsk_path_builder_add_path (builder, path);
+
+  gsk_path_unref (path);
+
+  cairo_path_destroy (cairo_path);
+  cairo_destroy (cr);
+  cairo_surface_destroy (surface);
+}

gsk/gskpathbuilder.h

@@ -0,0 +1,132 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#ifndef __GSK_PATH_BUILDER_H__
+#define __GSK_PATH_BUILDER_H__
+
+#if !defined (__GSK_H_INSIDE__) && !defined (GTK_COMPILATION)
+#error "Only <gsk/gsk.h> can be included directly."
+#endif
+
+
+#include <gsk/gskroundedrect.h>
+#include <gsk/gsktypes.h>
+
+G_BEGIN_DECLS
+
+#define GSK_TYPE_PATH_BUILDER (gsk_path_builder_get_type ())
+
+GDK_AVAILABLE_IN_ALL
+GType                   gsk_path_builder_get_type               (void) G_GNUC_CONST;
+
+GDK_AVAILABLE_IN_ALL
+GskPathBuilder *        gsk_path_builder_new                    (void);
+GDK_AVAILABLE_IN_ALL
+GskPathBuilder *        gsk_path_builder_ref                    (GskPathBuilder         *builder);
+GDK_AVAILABLE_IN_ALL
+void                    gsk_path_builder_unref                  (GskPathBuilder         *builder);
+GDK_AVAILABLE_IN_ALL
+GskPath *               gsk_path_builder_free_to_path           (GskPathBuilder         *builder) G_GNUC_WARN_UNUSED_RESULT;
+GDK_AVAILABLE_IN_ALL
+GskPath *               gsk_path_builder_to_path                (GskPathBuilder         *builder) G_GNUC_WARN_UNUSED_RESULT;
+
+GDK_AVAILABLE_IN_ALL
+const graphene_point_t *gsk_path_builder_get_current_point      (GskPathBuilder         *builder);
+
+GDK_AVAILABLE_IN_ALL
+void                    gsk_path_builder_add_path               (GskPathBuilder         *builder,
+                                                                 GskPath                *path);
+GDK_AVAILABLE_IN_ALL
+void                    gsk_path_builder_add_rect               (GskPathBuilder         *builder,
+                                                                 const graphene_rect_t  *rect);
+GDK_AVAILABLE_IN_ALL
+void                    gsk_path_builder_add_rounded_rect       (GskPathBuilder         *builder,
+                                                                 const GskRoundedRect   *rect);
+GDK_AVAILABLE_IN_ALL
+void                    gsk_path_builder_add_circle             (GskPathBuilder         *builder,
+                                                                 const graphene_point_t *center,
+                                                                 float                   radius);
+GDK_AVAILABLE_IN_ALL
+void                    gsk_path_builder_add_ellipse            (GskPathBuilder         *builder,
+                                                                 const graphene_point_t *center,
+                                                                 const graphene_size_t  *radius);
+/* next function implemented in gskpathmeasure.c */
+GDK_AVAILABLE_IN_ALL
+void                    gsk_path_builder_add_segment            (GskPathBuilder         *builder,
+                                                                 GskPathMeasure         *measure,
+                                                                 float                   start,
+                                                                 float                   end);
+
+
+GDK_AVAILABLE_IN_ALL
+void                    gsk_path_builder_move_to                (GskPathBuilder         *builder,
+                                                                 float                   x,
+                                                                 float                   y);
+GDK_AVAILABLE_IN_ALL
+void                    gsk_path_builder_rel_move_to            (GskPathBuilder         *builder,
+                                                                 float                   x,
+                                                                 float                   y);
+GDK_AVAILABLE_IN_ALL
+void                    gsk_path_builder_line_to                (GskPathBuilder         *builder,
+                                                                 float                   x,
+                                                                 float                   y);
+GDK_AVAILABLE_IN_ALL
+void                    gsk_path_builder_rel_line_to            (GskPathBuilder         *builder,
+                                                                 float                   x,
+                                                                 float                   y);
+GDK_AVAILABLE_IN_ALL
+void                    gsk_path_builder_curve_to               (GskPathBuilder         *builder,
+                                                                 float                   x1,
+                                                                 float                   y1,
+                                                                 float                   x2,
+                                                                 float                   y2,
+                                                                 float                   x3,
+                                                                 float                   y3);
+GDK_AVAILABLE_IN_ALL
+void                    gsk_path_builder_rel_curve_to           (GskPathBuilder         *builder,
+                                                                 float                   x1,
+                                                                 float                   y1,
+                                                                 float                   x2,
+                                                                 float                   y2,
+                                                                 float                   x3,
+                                                                 float                   y3);
+GDK_AVAILABLE_IN_ALL
+void                    gsk_path_builder_conic_to               (GskPathBuilder         *builder,
+                                                                 float                   x1,
+                                                                 float                   y1,
+                                                                 float                   x2,
+                                                                 float                   y2,
+                                                                 float                   weight);
+GDK_AVAILABLE_IN_ALL
+void                    gsk_path_builder_rel_conic_to           (GskPathBuilder         *builder,
+                                                                 float                   x1,
+                                                                 float                   y1,
+                                                                 float                   x2,
+                                                                 float                   y2,
+                                                                 float                   weight);
+GDK_AVAILABLE_IN_ALL
+void                    gsk_path_builder_close                  (GskPathBuilder         *builder);
+
+GDK_AVAILABLE_IN_ALL
+void                    gsk_path_builder_add_layout             (GskPathBuilder         *builder,
+                                                                 PangoLayout            *layout);
+
+G_END_DECLS
+
+#endif /* __GSK_PATH_BUILDER_H__ */

gsk/gskpathdash.c

@@ -0,0 +1,291 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#include "config.h"
+
+#include "gskpathdashprivate.h"
+
+#include "gskcontourprivate.h"
+#include "gskcurveprivate.h"
+#include "gskpathprivate.h"
+#include "gskstrokeprivate.h"
+
+typedef struct 
+{
+  float offset;                 /* how much of the current dash we've spent */
+  gsize dash_index;             /* goes from 0 to n_dash * 2, so we don't have to care about on/off
+                                   for uneven dashes */
+  gboolean on;                  /* If we're currently dashing or not */
+  gboolean may_close;           /* TRUE if we haven't turned the dash off in this contour */
+  gboolean needs_move_to;       /* If we have emitted the initial move_to() yet */
+  enum {
+    NORMAL, /* no special behavior required */
+    SKIP,   /* skip the next dash */
+    ONLY,   /* only do the first dash */
+    DONE    /* done with the first dash */
+  } first_dash_behavior;        /* How to handle the first dash in the loop. We loop closed contours
+                                   twice to make sure the first dash and the last dash can get joined */
+
+  GskCurve curve;               /* Curve we are currently processing */
+
+  float collect_start;          /* We're collecting multiple line segments when decomposing. */
+  float collect_length;         /* No need to emit a curve for every line segment when the dash is long enough. */
+
+  /* from the stroke */
+  float *dash;
+  gsize n_dash;
+  float dash_length;
+  float dash_offset;
+
+  float tolerance;
+  GskPathForeachFunc func;
+  gpointer user_data;
+} GskPathDash;
+
+static void
+gsk_path_dash_setup (GskPathDash *self)
+{
+  self->offset = fmodf (self->dash_offset, 2 * self->dash_length);
+
+  self->dash_index = 0;
+  self->on = TRUE;
+  self->may_close = TRUE;
+  while (self->offset > self->dash[self->dash_index % self->n_dash])
+    {
+      self->offset -= self->dash[self->dash_index % self->n_dash];
+      self->dash_index++;
+      self->on = !self->on;
+    }
+  if (self->first_dash_behavior != ONLY)
+    self->needs_move_to = TRUE;
+}
+
+static gboolean
+gsk_path_dash_ensure_move_to (GskPathDash            *self,
+                              const graphene_point_t *pt)
+{
+  if (!self->needs_move_to)
+    return TRUE;
+
+  if (!self->func (GSK_PATH_MOVE, pt, 1, 0, self->user_data))
+    return FALSE;
+
+  self->needs_move_to = FALSE;
+  return TRUE;
+}
+
+static gboolean
+gsk_path_dash_add_line_segment (const graphene_point_t *start,
+                                const graphene_point_t *end,
+                                float                   t_start,
+                                float                   t_end,
+                                gpointer                user_data)
+{
+  GskPathDash *self = user_data;
+  float remaining, length, t_step;
+
+  length = graphene_point_distance (start, end, NULL, NULL);
+  if (self->collect_length)
+    {
+      t_start = self->collect_start;
+      length += self->collect_length;
+      self->collect_length = 0;
+    }
+
+  t_step = t_end - t_start;
+  remaining = length;
+
+  while (remaining)
+    {
+      float piece;
+
+      if (self->offset + remaining <= self->dash[self->dash_index % self->n_dash])
+        {
+          /* try collecting multiple line segments */
+          if (t_end < 1.0)
+            {
+              self->collect_start = t_start + t_step * (length - remaining) / length;
+              self->collect_length = remaining;
+              return TRUE;
+            }
+
+          piece = remaining;
+        }
+      else
+        piece = self->dash[self->dash_index % self->n_dash] - self->offset;
+
+      if (self->on)
+        {
+          if (self->first_dash_behavior != SKIP)
+            {
+              GskCurve segment;
+
+              if (piece)
+                {
+                  gsk_curve_segment (&self->curve,
+                                     t_start + t_step * (length - remaining) / length,
+                                     t_start + t_step * (length - (remaining - piece)) / length,
+                                     &segment);
+                  if (!gsk_path_dash_ensure_move_to (self, gsk_curve_get_start_point (&segment)))
+                    return FALSE;
+
+                  if (!gsk_pathop_foreach (gsk_curve_pathop (&segment), self->func, self->user_data))
+                    return FALSE;
+                }
+              else
+                {
+                  graphene_point_t p;
+
+                  gsk_curve_get_point (&self->curve, t_start + t_step * (length - remaining) / length, &p);
+                  if (!gsk_path_dash_ensure_move_to (self, &p))
+                    return FALSE;
+                }
+            }
+        }
+      else
+        {
+          self->may_close = FALSE;
+          if (self->first_dash_behavior == ONLY)
+            {
+              self->first_dash_behavior = DONE;
+              return FALSE;
+            }
+          self->first_dash_behavior = NORMAL;
+        }
+
+      if (self->offset + remaining <= self->dash[self->dash_index % self->n_dash])
+        {
+          self->offset += remaining;
+          remaining = 0;
+        }
+      else
+        {
+          remaining -= piece;
+          self->offset = 0;
+          self->dash_index++;
+          self->dash_index %= 2 * self->n_dash;
+          self->on = !self->on;
+          self->needs_move_to = TRUE;
+        }
+    }
+
+  return TRUE;
+}
+
+static gboolean
+gsk_path_dash_foreach (GskPathOperation        op,
+                       const graphene_point_t *pts,
+                       gsize                   n_pts,
+                       float                   weight,
+                       gpointer                user_data)
+{
+  GskPathDash *self = user_data;
+
+  switch (op)
+  {
+    case GSK_PATH_MOVE:
+      gsk_path_dash_setup (self);
+      break;
+
+    case GSK_PATH_CLOSE:
+      if (self->may_close)
+        {
+          if (graphene_point_equal (&pts[0], &pts[1]))
+            return self->func (GSK_PATH_CLOSE, pts, 2, 0, self->user_data);
+        }
+      else
+        op = GSK_PATH_LINE;
+      G_GNUC_FALLTHROUGH;
+
+    case GSK_PATH_LINE:
+    case GSK_PATH_CURVE:
+    case GSK_PATH_CONIC:
+      gsk_curve_init_foreach (&self->curve, op, pts, n_pts, weight);
+      if (!gsk_curve_decompose (&self->curve, self->tolerance, gsk_path_dash_add_line_segment, self))
+        return FALSE;
+      break;
+
+    default:
+      g_assert_not_reached ();
+      break;
+  }
+
+  return TRUE;
+}
+
+gboolean
+gsk_contour_dash (const GskContour   *contour,
+                  GskStroke          *stroke,
+                  float               tolerance,
+                  GskPathForeachFunc  func,
+                  gpointer            user_data)
+{
+  GskPathDash self = {
+    .offset = 0,
+    .dash = stroke->dash,
+    .n_dash = stroke->n_dash,
+    .dash_length = stroke->dash_length,
+    .dash_offset = stroke->dash_offset,
+    .tolerance = tolerance,
+    .func = func,
+    .user_data = user_data
+  };
+  gboolean is_closed = gsk_contour_get_flags (contour) & GSK_PATH_CLOSED ? TRUE : FALSE;
+
+  self.first_dash_behavior = is_closed ? SKIP : NORMAL;
+  if (!gsk_contour_foreach (contour, tolerance, gsk_path_dash_foreach, &self))
+    return FALSE;
+
+  if (is_closed)
+    {
+      if (self.first_dash_behavior == NORMAL)
+        self.first_dash_behavior = ONLY;
+      else
+        self.first_dash_behavior = NORMAL;
+      self.needs_move_to = !self.on;
+      if (!gsk_contour_foreach (contour, tolerance, gsk_path_dash_foreach, &self) &&
+          self.first_dash_behavior != DONE)
+        return FALSE;
+    }
+
+  return TRUE;
+}
+
+gboolean
+gsk_path_dash (GskPath            *path,
+               GskStroke          *stroke,
+               float               tolerance,
+               GskPathForeachFunc  func,
+               gpointer            user_data)
+{
+  gsize i;
+
+  /* Dashing disabled, no need to do any work */
+  if (stroke->dash_length <= 0)
+    return gsk_path_foreach (path, -1, func, user_data);
+
+  for (i = 0; i < gsk_path_get_n_contours (path); i++)
+    {
+      if (!gsk_contour_dash (gsk_path_get_contour (path, i), stroke, tolerance, func, user_data))
+        return FALSE;
+    }
+
+  return TRUE;
+}
+

gsk/gskpathdashprivate.h

@@ -0,0 +1,50 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+
+#ifndef __GSK_PATH_DASH_PRIVATE_H__
+#define __GSK_PATH_DASH_PRIVATE_H__
+
+#include <gsk/gskpath.h>
+
+G_BEGIN_DECLS
+
+GDK_AVAILABLE_IN_ALL
+gboolean                gsk_path_dash                           (GskPath                *path,
+                                                                 GskStroke              *stroke,
+                                                                 float                   tolerance,
+                                                                 GskPathForeachFunc      func,
+                                                                 gpointer                user_data);
+
+#ifdef GTK_COMPILATION
+
+#include "gskcontourprivate.h"
+
+gboolean                gsk_contour_dash                        (const GskContour       *contour,
+                                                                 GskStroke              *stroke,
+                                                                 float                   tolerance,
+                                                                 GskPathForeachFunc      func,
+                                                                 gpointer                user_data);
+
+#endif /* GTK_COMPILATION */
+
+G_END_DECLS
+
+#endif /* __GSK_PATH_DASH_PRIVATE_H__ */
+

gsk/gskpathmeasure.c

@@ -0,0 +1,677 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#include "config.h"
+
+#include "gskpathmeasure.h"
+#include "gskpathbuilder.h"
+
+#include "gskpathbuilder.h"
+#include "gskpathprivate.h"
+
+/**
+ * GskPathMeasure:
+ *
+ * `GskPathMeasure` is an object that allows measuring operations
+ * on `GskPath` objects, to determine quantities like the arc
+ * length of the path, its curvature, or closest points.
+ *
+ * These operations are useful when implementing animations.
+ */
+
+typedef struct _GskContourMeasure GskContourMeasure;
+
+struct _GskContourMeasure
+{
+  float length;
+  gpointer contour_data;
+};
+
+struct _GskPathMeasure
+{
+  /*< private >*/
+  guint ref_count;
+
+  GskPath *path;
+  float tolerance;
+
+  gsize first;
+  gsize last;
+
+  float length;
+  gsize n_contours;
+  GskContourMeasure measures[];
+};
+
+G_DEFINE_BOXED_TYPE (GskPathMeasure, gsk_path_measure,
+                     gsk_path_measure_ref,
+                     gsk_path_measure_unref)
+
+/**
+ * gsk_path_measure_new:
+ * @path: the path to measure
+ *
+ * Creates a measure object for the given @path with a
+ * default tolerance.
+ *
+ * Returns: a new `GskPathMeasure` representing @path
+ **/
+GskPathMeasure *
+gsk_path_measure_new (GskPath *path)
+{
+  return gsk_path_measure_new_with_tolerance (path, GSK_PATH_TOLERANCE_DEFAULT);
+}
+
+/**
+ * gsk_path_measure_new_with_tolerance:
+ * @path: the path to measure
+ * @tolerance: the tolerance for measuring operations
+ *
+ * Creates a measure object for the given @path and @tolerance.
+ *
+ * Returns: a new `GskPathMeasure` representing @path
+ **/
+GskPathMeasure *
+gsk_path_measure_new_with_tolerance (GskPath *path,
+                                     float    tolerance)
+{
+  GskPathMeasure *self;
+  gsize i, n_contours;
+
+  g_return_val_if_fail (path != NULL, NULL);
+  g_return_val_if_fail (tolerance > 0, NULL);
+
+  n_contours = gsk_path_get_n_contours (path);
+
+  self = g_malloc0 (sizeof (GskPathMeasure) + n_contours * sizeof (GskContourMeasure));
+
+  self->ref_count = 1;
+  self->path = gsk_path_ref (path);
+  self->tolerance = tolerance;
+  self->n_contours = n_contours;
+  self->first = 0;
+  self->last = n_contours;
+
+  for (i = 0; i < n_contours; i++)
+    {
+      self->measures[i].contour_data = gsk_contour_init_measure (gsk_path_get_contour (path, i),
+                                                                 self->tolerance,
+                                                                 &self->measures[i].length);
+      self->length += self->measures[i].length;
+    }
+
+  return self;
+}
+
+/**
+ * gsk_path_measure_ref:
+ * @self: a `GskPathMeasure`
+ *
+ * Increases the reference count of a `GskPathMeasure` by one.
+ *
+ * Returns: the passed in `GskPathMeasure`.
+ **/
+GskPathMeasure *
+gsk_path_measure_ref (GskPathMeasure *self)
+{
+  g_return_val_if_fail (self != NULL, NULL);
+
+  self->ref_count++;
+
+  return self;
+}
+
+/**
+ * gsk_path_measure_unref:
+ * @self: a `GskPathMeasure`
+ *
+ * Decreases the reference count of a `GskPathMeasure` by one.
+ *
+ * If the resulting reference count is zero, frees the object.
+ **/
+void
+gsk_path_measure_unref (GskPathMeasure *self)
+{
+  gsize i;
+
+  g_return_if_fail (self != NULL);
+  g_return_if_fail (self->ref_count > 0);
+
+  self->ref_count--;
+  if (self->ref_count > 0)
+    return;
+
+  for (i = 0; i < self->n_contours; i++)
+    {
+      gsk_contour_free_measure (gsk_path_get_contour (self->path, i),
+                                self->measures[i].contour_data);
+    }
+
+  gsk_path_unref (self->path);
+  g_free (self);
+}
+
+/**
+ * gsk_path_measure_get_path:
+ * @self: a `GskPathMeasure`
+ *
+ * Returns the path that the measure was created for.
+ *
+ * Returns: (transfer none): the path of @self
+ */
+GskPath *
+gsk_path_measure_get_path (GskPathMeasure *self)
+{
+  g_return_val_if_fail (self != NULL, NULL);
+
+  return self->path;
+}
+
+/**
+ * gsk_path_measure_get_tolerance:
+ * @self: a `GskPathMeasure`
+ *
+ * Returns the tolerance that the measure was created with.
+ *
+ * Returns: the tolerance of @self
+ */
+float
+gsk_path_measure_get_tolerance (GskPathMeasure *self)
+{
+  g_return_val_if_fail (self != NULL, 0.f);
+
+  return self->tolerance;
+}
+
+/**
+ * gsk_path_measure_get_n_contours:
+ * @self: a `GskPathMeasure`
+ *
+ * Returns the number of contours in the path being measured.
+ *
+ * The returned value is independent of whether @self if restricted
+ * or not.
+ *
+ * Returns: The number of contours
+ **/
+gsize
+gsk_path_measure_get_n_contours (GskPathMeasure *self)
+{
+  g_return_val_if_fail (self != NULL, 0);
+
+  return self->n_contours;
+}
+
+/**
+ * gsk_path_measure_restrict_to_contour:
+ * @self: a `GskPathMeasure`
+ * @contour: contour to restrict to or (gsize) -1 for using the
+ *   whole path
+ *
+ * Restricts all functions on the path to just the given @contour.
+ *
+ * If @contour >= gsk_path_measure_get_n_contours() - so in
+ * particular when it is set to -1 - the whole path will be used.
+ **/
+void
+gsk_path_measure_restrict_to_contour (GskPathMeasure *self,
+                                      gsize           contour)
+{
+  if (contour >= self->n_contours)
+    {
+      /* use the whole path */
+      self->first = 0;
+      self->last = self->n_contours;
+    }
+  else
+    {
+      /* use just one contour */
+      self->first = contour;
+      self->last = contour + 1;
+    }
+
+  self->length = 0;
+  for (gsize i = self->first; i < self->last; i++)
+    {
+      self->length += self->measures[i].length;
+    }
+}
+
+/**
+ * gsk_path_measure_get_length:
+ * @self: a `GskPathMeasure`
+ *
+ * Gets the length of the path being measured.
+ *
+ * The length is cached, so this function does not do any work.
+ *
+ * Returns: The length of the path measured by @self
+ **/
+float
+gsk_path_measure_get_length (GskPathMeasure *self)
+{
+  g_return_val_if_fail (self != NULL, 0);
+
+  return self->length;
+}
+
+/**
+ * gsk_path_measure_is_closed:
+ * @self: a `GskPathMeasure`
+ *
+ * Returns if the path being measured represents a single closed
+ * contour.
+ *
+ * Returns: %TRUE if the current path is closed
+ **/
+gboolean
+gsk_path_measure_is_closed (GskPathMeasure *self)
+{
+  const GskContour *contour;
+
+  g_return_val_if_fail (self != NULL, FALSE);
+
+  /* XXX: is the empty path closed? Currently it's not */
+  if (self->last - self->first != 1)
+    return FALSE;
+
+  contour = gsk_path_get_contour (self->path, self->first);
+  return gsk_contour_get_flags (contour) & GSK_PATH_CLOSED ? TRUE : FALSE;
+}
+
+static float
+gsk_path_measure_clamp_distance (GskPathMeasure *self,
+                                 float           distance)
+{
+  if (isnan (distance))
+    return 0;
+
+  return CLAMP (distance, 0, self->length);
+}
+
+/**
+ * gsk_path_measure_get_point:
+ * @self: a `GskPathMeasure`
+ * @distance: distance into the path
+ * @pos: (optional) (out caller-allocates): The coordinates
+ *   of the position at @distance
+ * @tangent: (optional) (out caller-allocates): The tangent
+ *   to the position at @distance
+ *
+ * Calculates the coordinates and tangent of the point @distance
+ * units into the path. The value will be clamped to the length
+ * of the path.
+ *
+ * If the point is a discontinuous edge in the path, the returned
+ * point and tangent will describe the line starting at that point
+ * going forward.
+ *
+ * If @self describes an empty path, the returned point will be
+ * set to `(0, 0)` and the tangent will be the x axis or `(1, 0)`.
+ **/
+void
+gsk_path_measure_get_point (GskPathMeasure   *self,
+                            float             distance,
+                            graphene_point_t *pos,
+                            graphene_vec2_t  *tangent)
+{
+  gsize i;
+
+  g_return_if_fail (self != NULL);
+
+  if (pos == NULL && tangent == NULL)
+    return;
+
+  distance = gsk_path_measure_clamp_distance (self, distance);
+
+  for (i = self->first; i < self->last; i++)
+    {
+      if (distance < self->measures[i].length)
+        break;
+
+      distance -= self->measures[i].length;
+    }
+
+  /* weird corner cases */
+  if (i == self->last)
+    {
+      /* the empty path goes here */
+      if (self->first == self->last)
+        {
+          if (pos)
+            graphene_point_init (pos, 0.f, 0.f);
+          if (tangent)
+            graphene_vec2_init (tangent, 1.f, 0.f);
+          return;
+        }
+      /* rounding errors can make this happen */
+      i = self->last - 1;
+      distance = self->measures[i].length;
+    }
+
+  gsk_contour_get_point (gsk_path_get_contour (self->path, i),
+                         self->measures[i].contour_data,
+                         distance,
+                         pos,
+                         tangent);
+}
+
+/**
+ * gsk_path_measure_get_curvature:
+ * @self: a `GskPathMeasure`
+ * @distance: distance into the path
+ * @center: (optional) (out caller-allocates): The center
+ *   of the osculating circle at the point
+ *
+ * Calculates the curvature at the point @distance units into
+ * the path.
+ *
+ * Optionally, returns the center of the osculating circle as well.
+ *
+ * If the curvature is infinite (at line segments), or does
+ * not exist (at sharp turns), zero is returned, and @center
+ * is not modified.
+ *
+ * Returns: The curvature of the path at the given point
+ */
+float
+gsk_path_measure_get_curvature (GskPathMeasure   *self,
+                                float             distance,
+                                graphene_point_t *center)
+{
+  gsize i;
+
+  g_return_val_if_fail (self != NULL, 0);
+
+  distance = gsk_path_measure_clamp_distance (self, distance);
+
+  for (i = self->first; i < self->last; i++)
+    {
+      if (distance < self->measures[i].length)
+        break;
+
+      distance -= self->measures[i].length;
+    }
+
+  /* weird corner cases */
+  if (i == self->last)
+    {
+      /* the empty path goes here */
+      if (self->first == self->last)
+        return 0;
+
+      /* rounding errors can make this happen */
+      i = self->last - 1;
+      distance = self->measures[i].length;
+    }
+
+  return gsk_contour_get_curvature (gsk_path_get_contour (self->path, i),
+                                    self->measures[i].contour_data,
+                                    distance,
+                                    center);
+}
+
+/**
+ * gsk_path_measure_get_closest_point:
+ * @self: a `GskPathMeasure`
+ * @point: the point to find the closest point to
+ * @out_pos: (optional) (out caller-allocates): return location
+ *   for the closest point
+ *
+ * Gets the point on the path that is closest to @point.
+ *
+ * If the path being measured is empty, return 0 and set
+ * @out_pos to (0, 0).
+ *
+ * This is a simpler and slower version of
+ * [method@Gsk.PathMeasure.get_closest_point_full].
+ * Use that one if you need more control.
+ *
+ * Returns: The offset into the path of the closest point
+ **/
+float
+gsk_path_measure_get_closest_point (GskPathMeasure         *self,
+                                    const graphene_point_t *point,
+                                    graphene_point_t       *out_pos)
+{
+  float result;
+
+  g_return_val_if_fail (self != NULL, 0.0f);
+
+  if (gsk_path_measure_get_closest_point_full (self,
+                                               point,
+                                               INFINITY,
+                                               NULL,
+                                               out_pos,
+                                               &result,
+                                               NULL))
+    return result;
+
+  if (out_pos)
+    *out_pos = GRAPHENE_POINT_INIT (0, 0);
+
+  return 0;
+
+}
+
+/**
+ * gsk_path_measure_get_closest_point_full:
+ * @self: a `GskPathMeasure`
+ * @point: the point to find the closest point to
+ * @threshold: The maximum allowed distance between the path and @point.
+ *   Use INFINITY to look for any point.
+ * @out_distance: (optional) (out caller-allocates): The
+ *   distance between the found closest point on the path and the given
+ *   @point.
+ * @out_pos: (optional) (out caller-allocates): return location
+ *   for the closest point
+ * @out_offset: (optional) (out caller-allocates): The offset into
+ *   the path of the found point
+ * @out_tangent: (optional) (out caller-allocates): return location for
+ *   the tangent at the closest point
+ *
+ * Gets the point on the path that is closest to @point. If no point on
+ * path is closer to @point than @threshold, return %FALSE.
+ *
+ * Returns: %TRUE if a point was found, %FALSE otherwise.
+ **/
+gboolean
+gsk_path_measure_get_closest_point_full (GskPathMeasure         *self,
+                                         const graphene_point_t *point,
+                                         float                   threshold,
+                                         float                  *out_distance,
+                                         graphene_point_t       *out_pos,
+                                         float                  *out_offset,
+                                         graphene_vec2_t        *out_tangent)
+{
+  gboolean result;
+  gsize i;
+  float distance, length;
+
+  g_return_val_if_fail (self != NULL, FALSE);
+  g_return_val_if_fail (point != NULL, FALSE);
+
+  result = FALSE;
+  length = 0;
+
+  for (i = self->first; i < self->last; i++)
+    {
+      if (gsk_contour_get_closest_point (gsk_path_get_contour (self->path, i),
+                                         self->measures[i].contour_data,
+                                         self->tolerance,
+                                         point,
+                                         threshold,
+                                         &distance,
+                                         out_pos,
+                                         out_offset,
+                                         out_tangent))
+        {
+          result = TRUE;
+          if (out_offset)
+            *out_offset += length;
+
+          if (distance < self->tolerance)
+            break;
+          threshold = distance - self->tolerance;
+        }
+
+      length += self->measures[i].length;
+    }
+
+  if (result && out_distance)
+    *out_distance = distance;
+
+  return result;
+}
+
+/**
+ * gsk_path_measure_in_fill:
+ * @self: a #GskPathMeasure
+ * @point: the point to test
+ * @fill_rule: the fill rule to follow
+ *
+ * Returns whether the given point is inside the area that would be
+ * affected if the path of @self was filled according to @fill_rule.
+ *
+ * Returns: %TRUE if @point is inside
+ */
+gboolean
+gsk_path_measure_in_fill (GskPathMeasure   *self,
+                          graphene_point_t *point,
+                          GskFillRule       fill_rule)
+{
+  int winding = 0;
+  gboolean on_edge = FALSE;
+  int i;
+
+  for (i = self->first; i < self->last; i++)
+    {
+      winding += gsk_contour_get_winding (gsk_path_get_contour (self->path, i),
+                                          self->measures[i].contour_data,
+                                          point,
+                                          &on_edge);
+      if (on_edge)
+        return TRUE;
+    }
+
+  switch (fill_rule)
+    {
+    case GSK_FILL_RULE_EVEN_ODD:
+      return winding & 1;
+    case GSK_FILL_RULE_WINDING:
+      return winding != 0;
+    default:
+      g_assert_not_reached ();
+    }
+}
+
+static void
+gsk_path_builder_add_segment_chunk (GskPathBuilder *self,
+                                    GskPathMeasure *measure,
+                                    gboolean        emit_move_to,
+                                    float           start,
+                                    float           end)
+{
+  g_assert (start < end);
+
+  for (gsize i = measure->first; i < measure->last; i++)
+    {
+      if (measure->measures[i].length < start)
+        {
+          start -= measure->measures[i].length;
+          end -= measure->measures[i].length;
+        }
+      else if (start > 0 || end < measure->measures[i].length)
+        {
+          float len = MIN (end, measure->measures[i].length);
+          gsk_contour_add_segment (gsk_path_get_contour (measure->path, i),
+                                   self,
+                                   measure->measures[i].contour_data,
+                                   emit_move_to,
+                                   start,
+                                   len);
+          end -= len;
+          start = 0;
+          if (end <= 0)
+            break;
+        }
+      else
+        {
+          end -= measure->measures[i].length;
+          gsk_path_builder_add_contour (self, gsk_contour_dup (gsk_path_get_contour (measure->path, i)));
+        }
+      emit_move_to = TRUE;
+    }
+}
+
+/**
+ * gsk_path_builder_add_segment:
+ * @builder: a `GskPathBuilder`
+ * @measure: the `GskPathMeasure` to take the segment to
+ * @start: start distance into the path
+ * @end: end distance into the path
+ *
+ * Adds to @builder the segment of @measure from @start to @end.
+ *
+ * The distances are given relative to the length of @measure's path,
+ * from 0 for the beginning of the path to [method@Gsk.PathMeasure.get_length]
+ * for the end of the path. The values will be clamped to that range.
+ *
+ * If @start >= @end after clamping, the path will first add the segment
+ * from @start to the end of the path, and then add the segment from
+ * the beginning to @end. If the path is closed, these segments will
+ * be connected.
+ **/
+void
+gsk_path_builder_add_segment (GskPathBuilder *builder,
+                              GskPathMeasure *measure,
+                              float           start,
+                              float           end)
+{
+  g_return_if_fail (builder != NULL);
+  g_return_if_fail (measure != NULL);
+
+  start = gsk_path_measure_clamp_distance (measure, start);
+  end = gsk_path_measure_clamp_distance (measure, end);
+
+  if (start < end)
+    {
+      gsk_path_builder_add_segment_chunk (builder, measure, TRUE, start, end);
+    }
+  else
+    {
+      /* If the path is closed, we can connect the 2 subpaths. */
+      gboolean closed = gsk_path_measure_is_closed (measure);
+      gboolean need_move_to = !closed;
+
+      if (start < measure->length)
+        gsk_path_builder_add_segment_chunk (builder, measure,
+                                            TRUE,
+                                            start, measure->length);
+      else
+        need_move_to = TRUE;
+
+      if (end > 0)
+        gsk_path_builder_add_segment_chunk (builder, measure,
+                                            need_move_to,
+                                            0, end);
+      if (start == end && closed)
+        gsk_path_builder_close (builder);
+    }
+}

gsk/gskpathmeasure.h

@@ -0,0 +1,92 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#ifndef __GSK_PATH_MEASURE_H__
+#define __GSK_PATH_MEASURE_H__
+
+#if !defined (__GSK_H_INSIDE__) && !defined (GTK_COMPILATION)
+#error "Only <gsk/gsk.h> can be included directly."
+#endif
+
+
+#include <gsk/gskpath.h>
+
+G_BEGIN_DECLS
+
+#define GSK_TYPE_PATH_MEASURE (gsk_path_measure_get_type ())
+
+GDK_AVAILABLE_IN_ALL
+GType                   gsk_path_measure_get_type               (void) G_GNUC_CONST;
+GDK_AVAILABLE_IN_ALL
+GskPathMeasure *        gsk_path_measure_new                    (GskPath                *path);
+GDK_AVAILABLE_IN_ALL
+GskPathMeasure *        gsk_path_measure_new_with_tolerance     (GskPath                *path,
+                                                                 float                   tolerance);
+
+GDK_AVAILABLE_IN_ALL
+GskPathMeasure *        gsk_path_measure_ref                    (GskPathMeasure         *self);
+GDK_AVAILABLE_IN_ALL
+void                    gsk_path_measure_unref                  (GskPathMeasure         *self);
+
+GDK_AVAILABLE_IN_ALL
+GskPath *               gsk_path_measure_get_path               (GskPathMeasure         *self) G_GNUC_PURE;
+GDK_AVAILABLE_IN_ALL
+float                   gsk_path_measure_get_tolerance          (GskPathMeasure         *self) G_GNUC_PURE;
+GDK_AVAILABLE_IN_ALL
+gsize                   gsk_path_measure_get_n_contours         (GskPathMeasure         *self) G_GNUC_PURE;
+
+GDK_AVAILABLE_IN_ALL
+void                    gsk_path_measure_restrict_to_contour    (GskPathMeasure         *self,
+                                                                 gsize                   contour);
+
+GDK_AVAILABLE_IN_ALL
+float                   gsk_path_measure_get_length             (GskPathMeasure         *self);
+GDK_AVAILABLE_IN_ALL
+gboolean                gsk_path_measure_is_closed              (GskPathMeasure         *self);
+GDK_AVAILABLE_IN_ALL
+void                    gsk_path_measure_get_point              (GskPathMeasure         *self,
+                                                                 float                   distance,
+                                                                 graphene_point_t       *pos,
+                                                                 graphene_vec2_t        *tangent);
+GDK_AVAILABLE_IN_ALL
+float                   gsk_path_measure_get_curvature          (GskPathMeasure         *self,
+                                                                 float                   distance,
+                                                                 graphene_point_t       *center);
+
+GDK_AVAILABLE_IN_ALL
+float                   gsk_path_measure_get_closest_point      (GskPathMeasure         *self,
+                                                                 const graphene_point_t *point,
+                                                                 graphene_point_t       *out_pos);
+GDK_AVAILABLE_IN_ALL
+gboolean                gsk_path_measure_get_closest_point_full (GskPathMeasure         *self,
+                                                                 const graphene_point_t *point,
+                                                                 float                   threshold,
+                                                                 float                  *out_distance,
+                                                                 graphene_point_t       *out_pos,
+                                                                 float                  *out_offset,
+                                                                 graphene_vec2_t        *out_tangent);
+
+GDK_AVAILABLE_IN_ALL
+gboolean                gsk_path_measure_in_fill                (GskPathMeasure         *self,
+                                                                 graphene_point_t       *point,
+                                                                 GskFillRule             fill_rule);
+
+G_END_DECLS
+
+#endif /* __GSK_PATH_MEASURE_H__ */

gsk/gskpathopprivate.h

@@ -0,0 +1,179 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+
+#ifndef __GSK_PATHOP_PRIVATE_H__
+#define __GSK_PATHOP_PRIVATE_H__
+
+#include <gsk/gskpath.h>
+#include <gsk/gskpathbuilder.h>
+
+G_BEGIN_DECLS
+
+typedef gpointer gskpathop;
+
+static inline
+gskpathop               gsk_pathop_encode                       (GskPathOperation        op,
+                                                                 const graphene_point_t *pts);
+static inline
+const graphene_point_t *gsk_pathop_points                       (gskpathop               pop);
+static inline
+GskPathOperation        gsk_pathop_op                           (gskpathop               pop);
+
+static inline
+gboolean                gsk_pathop_foreach                      (gskpathop               pop,
+                                                                 GskPathForeachFunc      func,
+                                                                 gpointer                user_data);
+
+/* included inline so tests can use them */
+static inline
+void                    gsk_path_builder_pathop_to              (GskPathBuilder         *builder,
+                                                                 gskpathop               op);
+static inline
+void                    gsk_path_builder_pathop_reverse_to      (GskPathBuilder         *builder,
+                                                                 gskpathop               op);
+
+/* IMPLEMENTATION */
+
+#define GSK_PATHOP_OPERATION_MASK (0x7)
+
+static inline gskpathop
+gsk_pathop_encode (GskPathOperation        op,
+                   const graphene_point_t *pts)
+{
+  /* g_assert (op & GSK_PATHOP_OPERATION_MASK == op); */
+  g_assert ((GPOINTER_TO_SIZE (pts) & GSK_PATHOP_OPERATION_MASK) == 0);
+
+  return GSIZE_TO_POINTER (GPOINTER_TO_SIZE (pts) | op);
+}
+
+static inline const graphene_point_t *
+gsk_pathop_points (gskpathop pop)
+{
+  return GSIZE_TO_POINTER (GPOINTER_TO_SIZE (pop) & ~GSK_PATHOP_OPERATION_MASK);
+}
+
+static inline
+GskPathOperation gsk_pathop_op (gskpathop pop)
+{
+  return GPOINTER_TO_SIZE (pop) & GSK_PATHOP_OPERATION_MASK;
+}
+
+static inline gboolean
+gsk_pathop_foreach (gskpathop          pop,
+                    GskPathForeachFunc func,
+                    gpointer           user_data)
+{
+  switch (gsk_pathop_op (pop))
+  {
+    case GSK_PATH_MOVE:
+      return func (gsk_pathop_op (pop), gsk_pathop_points (pop), 1, 0, user_data);
+
+    case GSK_PATH_CLOSE:
+    case GSK_PATH_LINE:
+      return func (gsk_pathop_op (pop), gsk_pathop_points (pop), 2, 0, user_data);
+
+    case GSK_PATH_CURVE:
+      return func (gsk_pathop_op (pop), gsk_pathop_points (pop), 4, 0, user_data);
+
+    case GSK_PATH_CONIC:
+      {
+        const graphene_point_t *pts = gsk_pathop_points (pop);
+        return func (gsk_pathop_op (pop), (graphene_point_t[3]) { pts[0], pts[1], pts[3] }, 3, pts[2].x, user_data);
+      }
+
+    default:
+      g_assert_not_reached ();
+      return TRUE;
+    }
+}
+
+static inline void
+gsk_path_builder_pathop_to (GskPathBuilder *builder,
+                            gskpathop       op)
+{
+  const graphene_point_t *pts = gsk_pathop_points (op);
+
+  switch (gsk_pathop_op (op))
+  {
+    case GSK_PATH_MOVE:
+      gsk_path_builder_move_to (builder, pts[0].x, pts[0].y);
+      break;
+
+    case GSK_PATH_CLOSE:
+      gsk_path_builder_close (builder);
+      break;
+
+    case GSK_PATH_LINE:
+      gsk_path_builder_line_to (builder, pts[1].x, pts[1].y);
+      break;
+
+    case GSK_PATH_CURVE:
+      gsk_path_builder_curve_to (builder, pts[1].x, pts[1].y, pts[2].x, pts[2].y, pts[3].x, pts[3].y);
+      break;
+
+    case GSK_PATH_CONIC:
+      gsk_path_builder_conic_to (builder, pts[1].x, pts[1].y, pts[3].x, pts[3].y, pts[2].x);
+      break;
+
+    default:
+      g_assert_not_reached ();
+      break;
+  }
+}
+
+static inline void
+gsk_path_builder_pathop_reverse_to (GskPathBuilder *builder,
+                                    gskpathop       op)
+{
+  const graphene_point_t *pts = gsk_pathop_points (op);
+
+  switch (gsk_pathop_op (op))
+  {
+    case GSK_PATH_MOVE:
+      gsk_path_builder_move_to (builder, pts[0].x, pts[0].y);
+      break;
+
+    case GSK_PATH_CLOSE:
+      gsk_path_builder_line_to (builder, pts[0].x, pts[0].y);
+      break;
+
+    case GSK_PATH_LINE:
+      gsk_path_builder_line_to (builder, pts[1].x, pts[1].y);
+      break;
+
+    case GSK_PATH_CURVE:
+      gsk_path_builder_curve_to (builder, pts[2].x, pts[2].y, pts[1].x, pts[1].y, pts[0].x, pts[0].y);
+      break;
+
+    case GSK_PATH_CONIC:
+      gsk_path_builder_conic_to (builder, pts[1].x, pts[1].y, pts[0].x, pts[0].y, pts[2].x);
+      break;
+
+    default:
+      g_assert_not_reached ();
+      break;
+  }
+}
+
+
+G_END_DECLS
+
+#endif /* __GSK_PATHOP_PRIVATE_H__ */
+

gsk/gskpathprivate.h

@@ -0,0 +1,78 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+
+#ifndef __GSK_PATH_PRIVATE_H__
+#define __GSK_PATH_PRIVATE_H__
+
+#include "gskpath.h"
+
+#include "gskcontourprivate.h"
+#include "gskpathopprivate.h"
+
+G_BEGIN_DECLS
+
+/* Same as Skia, so looks like a good value. ¯\_(ツ)_/¯ */
+#define GSK_PATH_TOLERANCE_DEFAULT (0.5)
+
+GskPath *               gsk_path_new_from_contours              (const GSList           *contours);
+
+gsize                   gsk_path_get_n_contours                 (GskPath                *path);
+const GskContour *      gsk_path_get_contour                    (GskPath                *path,
+                                                                 gsize                   i);
+
+GskPathFlags            gsk_path_get_flags                      (GskPath                *self);
+
+gboolean                gsk_path_foreach_with_tolerance         (GskPath                *self,
+                                                                 GskPathForeachFlags     flags,
+                                                                 double                  tolerance,
+                                                                 GskPathForeachFunc      func,
+                                                                 gpointer                user_data);
+
+
+void                    gsk_path_builder_add_contour            (GskPathBuilder         *builder,
+                                                                 GskContour             *contour);
+
+void                    gsk_path_builder_svg_arc_to             (GskPathBuilder         *builder,
+                                                                 float                   rx,
+                                                                 float                   ry,
+                                                                 float                   x_axis_rotation,
+                                                                 gboolean                large_arc,
+                                                                 gboolean                positive_sweep,
+                                                                 float                   x,
+                                                                 float                   y);
+
+typedef enum
+{
+  GSK_PATH_OP_SIMPLIFY,
+  GSK_PATH_OP_UNION,
+  GSK_PATH_OP_INTERSECTION,
+  GSK_PATH_OP_DIFFERENCE,
+  GSK_PATH_OP_XOR
+} GskPathOp;
+
+GskPath *               gsk_path_op                             (GskPathOp               operation,
+                                                                 GskPath                *first,
+                                                                 GskPath                *second);
+
+
+G_END_DECLS
+
+#endif /* __GSK_PATH_PRIVATE_H__ */
+

gsk/gskrendernode.h

@@ -158,6 +158,8 @@ GskRenderNode *         gsk_render_node_deserialize             (GBytes
 #define GSK_TYPE_REPEAT_NODE                    (gsk_repeat_node_get_type())
 #define GSK_TYPE_CLIP_NODE                      (gsk_clip_node_get_type())
 #define GSK_TYPE_ROUNDED_CLIP_NODE              (gsk_rounded_clip_node_get_type())
+#define GSK_TYPE_FILL_NODE                      (gsk_fill_node_get_type())
+#define GSK_TYPE_STROKE_NODE                    (gsk_stroke_node_get_type())
 #define GSK_TYPE_SHADOW_NODE                    (gsk_shadow_node_get_type())
 #define GSK_TYPE_BLEND_NODE                     (gsk_blend_node_get_type())
 #define GSK_TYPE_CROSS_FADE_NODE                (gsk_cross_fade_node_get_type())
@@ -184,6 +186,8 @@ typedef struct _GskColorMatrixNode              GskColorMatrixNode;
 typedef struct _GskRepeatNode                   GskRepeatNode;
 typedef struct _GskClipNode                     GskClipNode;
 typedef struct _GskRoundedClipNode              GskRoundedClipNode;
+typedef struct _GskFillNode                     GskFillNode;
+typedef struct _GskStrokeNode                   GskStrokeNode;
 typedef struct _GskShadowNode                   GskShadowNode;
 typedef struct _GskBlendNode                    GskBlendNode;
 typedef struct _GskCrossFadeNode                GskCrossFadeNode;
@@ -445,6 +449,32 @@ GskRenderNode *         gsk_rounded_clip_node_get_child         (const GskRender
 GDK_AVAILABLE_IN_ALL
 const GskRoundedRect *  gsk_rounded_clip_node_get_clip          (const GskRenderNode      *node) G_GNUC_PURE;
 
+GDK_AVAILABLE_IN_ALL
+GType                   gsk_fill_node_get_type                  (void) G_GNUC_CONST;
+GDK_AVAILABLE_IN_ALL
+GskRenderNode *         gsk_fill_node_new                       (GskRenderNode            *child,
+                                                                 GskPath                  *path,
+                                                                 GskFillRule               fill_rule);
+GDK_AVAILABLE_IN_ALL
+GskRenderNode *         gsk_fill_node_get_child                 (const GskRenderNode      *node);
+GDK_AVAILABLE_IN_ALL
+GskPath *               gsk_fill_node_get_path                  (const GskRenderNode      *node);
+GDK_AVAILABLE_IN_ALL
+GskFillRule             gsk_fill_node_get_fill_rule             (const GskRenderNode      *node);
+
+GDK_AVAILABLE_IN_ALL
+GType                   gsk_stroke_node_get_type                (void) G_GNUC_CONST;
+GDK_AVAILABLE_IN_ALL
+GskRenderNode *         gsk_stroke_node_new                     (GskRenderNode            *child,
+                                                                 GskPath                  *path,
+                                                                 const GskStroke          *stroke);
+GDK_AVAILABLE_IN_ALL
+GskRenderNode *         gsk_stroke_node_get_child               (const GskRenderNode      *node);
+GDK_AVAILABLE_IN_ALL
+GskPath *               gsk_stroke_node_get_path                (const GskRenderNode      *node);
+GDK_AVAILABLE_IN_ALL
+const GskStroke *       gsk_stroke_node_get_stroke              (const GskRenderNode      *node);
+
 GDK_AVAILABLE_IN_ALL
 GType                   gsk_shadow_node_get_type                (void) G_GNUC_CONST;
 GDK_AVAILABLE_IN_ALL

gsk/gskrendernodeimpl.c

@@ -23,8 +23,10 @@
 #include "gskcairoblurprivate.h"
 #include "gskdebugprivate.h"
 #include "gskdiffprivate.h"
+#include "gskpath.h"
 #include "gskrendererprivate.h"
 #include "gskroundedrectprivate.h"
+#include "gskstrokeprivate.h"
 #include "gsktransformprivate.h"
 
 #include "gdk/gdktextureprivate.h"
@@ -3761,6 +3763,343 @@ gsk_rounded_clip_node_get_clip (const GskRenderNode *node)
   return &self->clip;
 }
 
+/*** GSK_FILL_NODE ***/
+
+struct _GskFillNode
+{
+  GskRenderNode render_node;
+
+  GskRenderNode *child;
+  GskPath *path;
+  GskFillRule fill_rule;
+};
+
+static void
+gsk_fill_node_finalize (GskRenderNode *node)
+{
+  GskFillNode *self = (GskFillNode *) node;
+  GskRenderNodeClass *parent_class = g_type_class_peek (g_type_parent (GSK_TYPE_FILL_NODE));
+
+  gsk_render_node_unref (self->child);
+  gsk_path_unref (self->path);
+
+  parent_class->finalize (node);
+}
+
+static void
+gsk_fill_node_draw (GskRenderNode *node,
+                    cairo_t       *cr)
+{
+  GskFillNode *self = (GskFillNode *) node;
+
+  cairo_save (cr);
+
+  switch (self->fill_rule)
+  {
+    case GSK_FILL_RULE_WINDING:
+      cairo_set_fill_rule (cr, CAIRO_FILL_RULE_WINDING);
+      break;
+    case GSK_FILL_RULE_EVEN_ODD:
+      cairo_set_fill_rule (cr, CAIRO_FILL_RULE_EVEN_ODD);
+      break;
+    default:
+      g_assert_not_reached ();
+      break;
+  }
+  gsk_path_to_cairo (self->path, cr);
+  cairo_clip (cr);
+
+  gsk_render_node_draw (self->child, cr);
+
+  cairo_restore (cr);
+}
+
+static void
+gsk_fill_node_diff (GskRenderNode  *node1,
+                    GskRenderNode  *node2,
+                    cairo_region_t *region)
+{
+  GskFillNode *self1 = (GskFillNode *) node1;
+  GskFillNode *self2 = (GskFillNode *) node2;
+
+  if (self1->path == self2->path)
+    {
+      cairo_region_t *sub;
+      cairo_rectangle_int_t clip_rect;
+      graphene_rect_t rect;
+
+      sub = cairo_region_create();
+      gsk_render_node_diff (self1->child, self2->child, sub);
+      graphene_rect_union (&node1->bounds, &node2->bounds, &rect);
+      rectangle_init_from_graphene (&clip_rect, &rect);
+      cairo_region_intersect_rectangle (sub, &clip_rect);
+      cairo_region_union (region, sub);
+      cairo_region_destroy (sub);
+    }
+  else
+    {
+      gsk_render_node_diff_impossible (node1, node2, region);
+    }
+}
+
+/**
+ * gsk_fill_node_new:
+ * @child: The node to fill the area with
+ * @path: The path describing the area to fill
+ * @fill_rule: The fill rule to use
+ *
+ * Creates a `GskRenderNode` that will fill the @child in the area
+ * given by @path and @fill_rule.
+ *
+ * Returns: (transfer none) (type GskFillNode): A new `GskRenderNode`
+ */
+GskRenderNode *
+gsk_fill_node_new (GskRenderNode *child,
+                   GskPath       *path,
+                   GskFillRule    fill_rule)
+{
+  GskFillNode *self;
+  GskRenderNode *node;
+  graphene_rect_t path_bounds;
+
+  g_return_val_if_fail (GSK_IS_RENDER_NODE (child), NULL);
+  g_return_val_if_fail (path != NULL, NULL);
+
+  self = gsk_render_node_alloc (GSK_FILL_NODE);
+  node = (GskRenderNode *) self;
+
+  self->child = gsk_render_node_ref (child);
+  self->path = gsk_path_ref (path);
+  self->fill_rule = fill_rule;
+
+  if (gsk_path_get_bounds (path, &path_bounds))
+    graphene_rect_intersection (&path_bounds, &child->bounds, &node->bounds);
+  else
+    graphene_rect_init_from_rect (&node->bounds, graphene_rect_zero ());
+
+  return node;
+}
+
+/**
+ * gsk_fill_node_get_child:
+ * @node: (type GskFillNode): a fill `GskRenderNode`
+ *
+ * Gets the child node that is getting drawn by the given @node.
+ *
+ * Returns: (transfer none): The child that is getting drawn
+ **/
+GskRenderNode *
+gsk_fill_node_get_child (const GskRenderNode *node)
+{
+  const GskFillNode *self = (const GskFillNode *) node;
+
+  g_return_val_if_fail (GSK_IS_RENDER_NODE_TYPE (node, GSK_FILL_NODE), NULL);
+
+  return self->child;
+}
+
+/**
+ * gsk_fill_node_get_path:
+ * @node: (type GskFillNode): a fill `GskRenderNode`
+ *
+ * Retrievs the path used to describe the area filled with the contents of
+ * the @node.
+ *
+ * Returns: (transfer none): a `GskPath`
+ */
+GskPath *
+gsk_fill_node_get_path (const GskRenderNode *node)
+{
+  const GskFillNode *self = (const GskFillNode *) node;
+
+  g_return_val_if_fail (GSK_IS_RENDER_NODE_TYPE (node, GSK_FILL_NODE), NULL);
+
+  return self->path;
+}
+
+/**
+ * gsk_fill_node_get_fill_rule:
+ * @node: (type GskFillNode): a fill `GskRenderNode`
+ *
+ * Retrievs the fill rule used to determine how the path is filled.
+ *
+ * Returns: a `GskFillRule`
+ */
+GskFillRule
+gsk_fill_node_get_fill_rule (const GskRenderNode *node)
+{
+  const GskFillNode *self = (const GskFillNode *) node;
+
+  g_return_val_if_fail (GSK_IS_RENDER_NODE_TYPE (node, GSK_FILL_NODE), GSK_FILL_RULE_WINDING);
+
+  return self->fill_rule;
+}
+
+/*** GSK_STROKE_NODE ***/
+
+struct _GskStrokeNode
+{
+  GskRenderNode render_node;
+
+  GskRenderNode *child;
+  GskPath *path;
+  GskStroke stroke;
+};
+
+static void
+gsk_stroke_node_finalize (GskRenderNode *node)
+{
+  GskStrokeNode *self = (GskStrokeNode *) node;
+  GskRenderNodeClass *parent_class = g_type_class_peek (g_type_parent (GSK_TYPE_STROKE_NODE));
+
+  gsk_render_node_unref (self->child);
+  gsk_path_unref (self->path);
+  gsk_stroke_clear (&self->stroke);
+
+  parent_class->finalize (node);
+}
+
+static void
+gsk_stroke_node_draw (GskRenderNode *node,
+                      cairo_t       *cr)
+{
+  GskStrokeNode *self = (GskStrokeNode *) node;
+
+  cairo_save (cr);
+
+  gsk_cairo_rectangle (cr, &self->child->bounds);
+  cairo_clip (cr);
+
+  cairo_push_group (cr);
+  gsk_render_node_draw (self->child, cr);
+  cairo_pop_group_to_source (cr);
+
+  gsk_stroke_to_cairo (&self->stroke, cr);
+
+  gsk_path_to_cairo (self->path, cr);
+  cairo_stroke (cr);
+
+  cairo_restore (cr);
+}
+
+static void
+gsk_stroke_node_diff (GskRenderNode  *node1,
+                      GskRenderNode  *node2,
+                      cairo_region_t *region)
+{
+  GskStrokeNode *self1 = (GskStrokeNode *) node1;
+  GskStrokeNode *self2 = (GskStrokeNode *) node2;
+
+  if (self1->path == self2->path &&
+      gsk_stroke_equal (&self1->stroke, &self2->stroke))
+    {
+      cairo_region_t *sub;
+
+      sub = cairo_region_create();
+      gsk_render_node_diff (self1->child, self2->child, sub);
+      cairo_region_union (region, sub);
+      cairo_region_destroy (sub);
+    }
+  else
+    {
+      gsk_render_node_diff_impossible (node1, node2, region);
+    }
+}
+
+/**
+ * gsk_stroke_node_new:
+ * @child: The node to stroke the area with
+ * @path: (transfer none): The path describing the area to stroke
+ * @stroke: (transfer none): The stroke attributes to use
+ *
+ * Creates a `GskRenderNode` that will stroke the @child along the given
+ * @path using the attributes defined in @stroke.
+ *
+ * Returns: (transfer none) (type GskStrokeNode): A new `GskRenderNode`
+ */
+GskRenderNode *
+gsk_stroke_node_new (GskRenderNode   *child,
+                     GskPath         *path,
+                     const GskStroke *stroke)
+{
+  GskStrokeNode *self;
+  GskRenderNode *node;
+  graphene_rect_t path_bounds;
+
+  g_return_val_if_fail (GSK_IS_RENDER_NODE (child), NULL);
+  g_return_val_if_fail (path != NULL, NULL);
+  g_return_val_if_fail (stroke != NULL, NULL);
+
+  self = gsk_render_node_alloc (GSK_STROKE_NODE);
+  node = (GskRenderNode *) self;
+
+  self->child = gsk_render_node_ref (child);
+  self->path = gsk_path_ref (path);
+  gsk_stroke_init_copy (&self->stroke, stroke);
+
+  if (gsk_path_get_stroke_bounds (path, stroke, &path_bounds))
+    graphene_rect_intersection (&path_bounds, &child->bounds, &node->bounds);
+  else
+    graphene_rect_init_from_rect (&node->bounds, graphene_rect_zero ());
+
+  return node;
+}
+
+/**
+ * gsk_stroke_node_get_child:
+ * @node: (type GskStrokeNode): a stroke `GskRenderNode`
+ *
+ * Gets the child node that is getting drawn by the given @node.
+ *
+ * Returns: (transfer none): The child that is getting drawn
+ **/
+GskRenderNode *
+gsk_stroke_node_get_child (const GskRenderNode *node)
+{
+  const GskStrokeNode *self = (const GskStrokeNode *) node;
+
+  g_return_val_if_fail (GSK_IS_RENDER_NODE_TYPE (node, GSK_STROKE_NODE), NULL);
+
+  return self->child;
+}
+
+/**
+ * gsk_stroke_node_get_path:
+ * @node: (type GskStrokeNode): a stroke `GskRenderNode`
+ *
+ * Retrievs the path that will be stroked with the contents of
+ * the @node.
+ *
+ * Returns: (transfer none): a `GskPath`
+ */
+GskPath *
+gsk_stroke_node_get_path (const GskRenderNode *node)
+{
+  const GskStrokeNode *self = (const GskStrokeNode *) node;
+
+  g_return_val_if_fail (GSK_IS_RENDER_NODE_TYPE (node, GSK_STROKE_NODE), NULL);
+
+  return self->path;
+}
+
+/**
+ * gsk_stroke_node_get_stroke:
+ * @node: (type GskStrokeNode): a stroke `GskRenderNode`
+ *
+ * Retrievs the stroke attributes used in this @node.
+ *
+ * Returns: a `GskStroke`
+ */
+const GskStroke *
+gsk_stroke_node_get_stroke (const GskRenderNode *node)
+{
+  const GskStrokeNode *self = (const GskStrokeNode *) node;
+
+  g_return_val_if_fail (GSK_IS_RENDER_NODE_TYPE (node, GSK_STROKE_NODE), NULL);
+
+  return &self->stroke;
+}
+
 /*** GSK_SHADOW_NODE ***/
 
 /**
@@ -5283,6 +5622,8 @@ GSK_DEFINE_RENDER_NODE_TYPE (gsk_color_matrix_node, GSK_COLOR_MATRIX_NODE)
 GSK_DEFINE_RENDER_NODE_TYPE (gsk_repeat_node, GSK_REPEAT_NODE)
 GSK_DEFINE_RENDER_NODE_TYPE (gsk_clip_node, GSK_CLIP_NODE)
 GSK_DEFINE_RENDER_NODE_TYPE (gsk_rounded_clip_node, GSK_ROUNDED_CLIP_NODE)
+GSK_DEFINE_RENDER_NODE_TYPE (gsk_fill_node, GSK_FILL_NODE)
+GSK_DEFINE_RENDER_NODE_TYPE (gsk_stroke_node, GSK_STROKE_NODE)
 GSK_DEFINE_RENDER_NODE_TYPE (gsk_shadow_node, GSK_SHADOW_NODE)
 GSK_DEFINE_RENDER_NODE_TYPE (gsk_blend_node, GSK_BLEND_NODE)
 GSK_DEFINE_RENDER_NODE_TYPE (gsk_cross_fade_node, GSK_CROSS_FADE_NODE)
@@ -5582,6 +5923,38 @@ gsk_render_node_init_types_once (void)
     gsk_render_node_types[GSK_ROUNDED_CLIP_NODE] = node_type;
   }
 
+  {
+    const GskRenderNodeTypeInfo node_info =
+    {
+      GSK_FILL_NODE,
+      sizeof (GskFillNode),
+      NULL,
+      gsk_fill_node_finalize,
+      gsk_fill_node_draw,
+      NULL,
+      gsk_fill_node_diff,
+    };
+
+    GType node_type = gsk_render_node_type_register_static (I_("GskFillNode"), &node_info);
+    gsk_render_node_types[GSK_FILL_NODE] = node_type;
+  }
+
+  {
+    const GskRenderNodeTypeInfo node_info =
+    {
+      GSK_STROKE_NODE,
+      sizeof (GskStrokeNode),
+      NULL,
+      gsk_stroke_node_finalize,
+      gsk_stroke_node_draw,
+      NULL,
+      gsk_stroke_node_diff,
+    };
+
+    GType node_type = gsk_render_node_type_register_static (I_("GskStrokeNode"), &node_info);
+    gsk_render_node_types[GSK_STROKE_NODE] = node_type;
+  }
+
   {
     const GskRenderNodeTypeInfo node_info =
     {

gsk/gskrendernodeparser.c

@@ -23,9 +23,13 @@
 
 #include "gskrendernodeparserprivate.h"
 
+#include "gskpath.h"
+#include "gskpathbuilder.h"
 #include "gskroundedrectprivate.h"
 #include "gskrendernodeprivate.h"
+#include "gskstroke.h"
 #include "gsktransformprivate.h"
+#include "gskenumtypes.h"
 
 #include "gdk/gdkrgbaprivate.h"
 #include "gdk/gdktextureprivate.h"
@@ -399,7 +403,10 @@ parse_string (GtkCssParser *parser,
 
   token = gtk_css_parser_get_token (parser);
   if (!gtk_css_token_is (token, GTK_CSS_TOKEN_STRING))
-    return FALSE;
+    {
+      gtk_css_parser_error_syntax (parser, "Expected a string");
+      return FALSE;
+    }
 
   s = g_strdup (token->string.string);
   gtk_css_parser_consume_token (parser);
@@ -955,6 +962,26 @@ create_default_render_node (void)
   return gsk_color_node_new (&GDK_RGBA("FF00CC"), &GRAPHENE_RECT_INIT (0, 0, 50, 50));
 }
 
+static GskPath *
+create_default_path (void)
+{
+  GskPathBuilder *builder;
+  guint i;
+
+  builder = gsk_path_builder_new ();
+
+  gsk_path_builder_move_to (builder, 25, 0);
+  for (i = 1; i < 5; i++)
+    {
+      gsk_path_builder_line_to (builder,
+                                sin (i * G_PI * 0.8) * 25 + 25,
+                                -cos (i * G_PI * 0.8) * 25 + 25);
+    }
+  gsk_path_builder_close (builder);
+
+  return gsk_path_builder_free_to_path (builder);
+}
+
 static GskRenderNode *
 parse_color_node (GtkCssParser *parser)
 {
@@ -1102,7 +1129,7 @@ parse_conic_gradient_node (GtkCssParser *parser)
       g_array_append_val (stops, to);
     }
 
-  result = gsk_conic_gradient_node_new (&bounds, &center, rotation, 
+  result = gsk_conic_gradient_node_new (&bounds, &center, rotation,
                                         (GskColorStop *) stops->data, stops->len);
 
   g_array_free (stops, TRUE);
@@ -1388,7 +1415,7 @@ parse_cairo_node (GtkCssParser *parser)
   parse_declarations (parser, declarations, G_N_ELEMENTS(declarations));
 
   node = gsk_cairo_node_new (&bounds);
-  
+
   if (surface != NULL)
     {
       cairo_t *cr = gsk_cairo_node_get_draw_context (node);
@@ -1765,6 +1792,208 @@ parse_rounded_clip_node (GtkCssParser *parser)
   return result;
 }
 
+static gboolean
+parse_path (GtkCssParser *parser,
+            gpointer      out_path)
+{
+  GskPath *path;
+  char *str = NULL;
+
+  if (!parse_string (parser, &str))
+    return FALSE;
+
+  path = gsk_path_parse (str);
+  g_free (str);
+
+  if (path == NULL)
+    {
+      gtk_css_parser_error_value (parser, "Invalid path");
+      return FALSE;
+    }
+
+  *((GskPath **) out_path) = path;
+
+  return TRUE;
+}
+
+static void
+clear_path (gpointer inout_path)
+{
+  g_clear_pointer ((GskPath **) inout_path, gsk_path_unref);
+}
+
+static gboolean
+parse_dash (GtkCssParser *parser,
+            gpointer      out_dash)
+{
+  GArray *dash;
+  double d;
+
+  /* because CSS does this, too */
+  if (gtk_css_parser_try_ident (parser, "none"))
+    {
+      *((GArray **) out_dash) = NULL;
+      return TRUE;
+    }
+
+  dash = g_array_new (FALSE, FALSE, sizeof (float));
+  do {
+    if (!gtk_css_parser_consume_number (parser, &d))
+      {
+        g_array_free (dash, TRUE);
+        return FALSE;
+      }
+
+    g_array_append_vals (dash, (float[1]) { d }, 1);
+  } while (gtk_css_parser_has_token (parser, GTK_CSS_TOKEN_SIGNLESS_NUMBER) ||
+           gtk_css_parser_has_token (parser, GTK_CSS_TOKEN_SIGNLESS_INTEGER));
+
+  *((GArray **) out_dash) = dash;
+
+  return TRUE;
+}
+
+static void
+clear_dash (gpointer inout_array)
+{
+  g_clear_pointer ((GArray **) inout_array, g_array_unref);
+}
+
+static gboolean
+parse_enum (GtkCssParser *parser,
+            GType         type,
+            gpointer      out_value)
+{
+  GEnumClass *class;
+  GEnumValue *v;
+  const GtkCssToken *token;
+
+  token = gtk_css_parser_get_token (parser);
+  if (!gtk_css_token_is (token, GTK_CSS_TOKEN_IDENT))
+    {
+      gtk_css_parser_error_syntax (parser, "Expected a valid identifier");
+      return FALSE;
+    }
+
+  class = g_type_class_ref (type);
+
+  v = g_enum_get_value_by_nick (class, token->string.string);
+  if (v == NULL)
+    {
+      gtk_css_parser_error_value (parser, "\"%s\" is not a valid identifier here", token->string.string);
+      g_type_class_unref (class);
+      return FALSE;
+    }
+
+  *(int*)out_value = v->value;
+
+  g_type_class_unref (class);
+
+  gtk_css_parser_consume_token (parser);
+
+  return TRUE;
+}
+
+static gboolean
+parse_fill_rule (GtkCssParser *parser,
+                 gpointer      out_rule)
+{
+  return parse_enum (parser, GSK_TYPE_FILL_RULE, out_rule);
+}
+
+static GskRenderNode *
+parse_fill_node (GtkCssParser *parser)
+{
+  GskRenderNode *child = NULL;
+  GskPath *path = NULL;
+  int rule = GSK_FILL_RULE_WINDING;
+  const Declaration declarations[] = {
+    { "child", parse_node, clear_node, &child },
+    { "path", parse_path, clear_path, &path },
+    { "fill-rule", parse_fill_rule, NULL, &rule },
+  };
+  GskRenderNode *result;
+
+  parse_declarations (parser, declarations, G_N_ELEMENTS (declarations));
+  if (child == NULL)
+    child = create_default_render_node ();
+  if (path == NULL)
+    path = create_default_path ();
+
+  result = gsk_fill_node_new (child, path, rule);
+
+  gsk_path_unref (path);
+
+  gsk_render_node_unref (child);
+
+  return result;
+}
+
+static gboolean
+parse_line_cap (GtkCssParser *parser,
+                gpointer      out)
+{
+  return parse_enum (parser, GSK_TYPE_LINE_CAP, out);
+}
+
+static gboolean
+parse_line_join (GtkCssParser *parser,
+                 gpointer      out)
+{
+  return parse_enum (parser, GSK_TYPE_LINE_JOIN, out);
+}
+
+static GskRenderNode *
+parse_stroke_node (GtkCssParser *parser)
+{
+  GskRenderNode *child = NULL;
+  GskPath *path = NULL;
+  double line_width = 1.0;
+  int line_cap = GSK_LINE_CAP_BUTT;
+  int line_join = GSK_LINE_JOIN_MITER;
+  double miter_limit = 4.0;
+  GArray *dash = NULL;
+  double dash_offset = 0.0;
+  GskStroke *stroke;
+
+  const Declaration declarations[] = {
+    { "child", parse_node, clear_node, &child },
+    { "path", parse_path, clear_path, &path },
+    { "line-width", parse_double, NULL, &line_width },
+    { "line-cap", parse_line_cap, NULL, &line_cap },
+    { "line-join", parse_line_join, NULL, &line_join },
+    { "miter-limit", parse_double, NULL, &miter_limit },
+    { "dash", parse_dash, clear_dash, &dash },
+    { "dash-offset", parse_double, NULL, &dash_offset},
+  };
+  GskRenderNode *result;
+
+  parse_declarations (parser, declarations, G_N_ELEMENTS (declarations));
+  if (child == NULL)
+    child = create_default_render_node ();
+  if (path == NULL)
+    path = create_default_path ();
+
+  stroke = gsk_stroke_new (line_width);
+  gsk_stroke_set_line_cap (stroke, line_cap);
+  gsk_stroke_set_line_join (stroke, line_join);
+  gsk_stroke_set_miter_limit (stroke, miter_limit);
+  if (dash)
+    {
+      gsk_stroke_set_dash (stroke, (float *) dash->data, dash->len);
+      g_array_free (dash, TRUE);
+    }
+  gsk_stroke_set_dash_offset (stroke, dash_offset);
+
+  result = gsk_stroke_node_new (child, path, stroke);
+
+  gsk_path_unref (path);
+  gsk_stroke_free (stroke);
+  gsk_render_node_unref (child);
+
+  return result;
+}
+
 static GskRenderNode *
 parse_shadow_node (GtkCssParser *parser)
 {
@@ -1834,6 +2063,7 @@ parse_node (GtkCssParser *parser,
     { "container", parse_container_node },
     { "cross-fade", parse_cross_fade_node },
     { "debug", parse_debug_node },
+    { "fill", parse_fill_node },
     { "inset-shadow", parse_inset_shadow_node },
     { "linear-gradient", parse_linear_gradient_node },
     { "radial-gradient", parse_radial_gradient_node },
@@ -1845,6 +2075,7 @@ parse_node (GtkCssParser *parser,
     { "repeating-radial-gradient", parse_repeating_radial_gradient_node },
     { "rounded-clip", parse_rounded_clip_node },
     { "shadow", parse_shadow_node },
+    { "stroke", parse_stroke_node },
     { "text", parse_text_node },
     { "texture", parse_texture_node },
     { "transform", parse_transform_node },
@@ -2100,7 +2331,7 @@ append_float_param (Printer    *p,
                     float       value,
                     float       default_value)
 {
-  /* Don't approximate-compare here, better be topo verbose */
+  /* Don't approximate-compare here, better be too verbose */
   if (value == default_value)
     return;
 
@@ -2275,8 +2506,11 @@ append_escaping_newlines (GString    *str,
     len = strcspn (string, "\n");
     g_string_append_len (str, string, len);
     string += len;
-    g_string_append (str, "\\\n");
-    string++;
+    if (*string)
+      {
+        g_string_append (str, "\\\n");
+        string++;
+      }
   } while (*string);
 }
 
@@ -2391,6 +2625,83 @@ gsk_text_node_serialize_glyphs (GskRenderNode *node,
     pango_glyph_string_free (ascii);
 }
 
+static const char *
+enum_to_nick (GType type,
+              int   value)
+{
+  GEnumClass *class;
+  GEnumValue *v;
+
+  class = g_type_class_ref (type);
+  v = g_enum_get_value (class, value);
+  g_type_class_unref (class);
+
+  return v->value_nick;
+}
+
+static void
+append_enum_param (Printer    *p,
+                   const char *param_name,
+                   GType       type,
+                   int         value)
+{
+  _indent (p);
+  g_string_append_printf (p->str, "%s: ", param_name);
+  g_string_append (p->str, enum_to_nick (type, value));
+  g_string_append_c (p->str, ';');
+  g_string_append_c (p->str, '\n');
+}
+
+static void
+append_path_param (Printer    *p,
+                   const char *param_name,
+                   GskPath    *path)
+{
+  char *str, *s;
+
+  _indent (p);
+  g_string_append (p->str, "path: \"\\\n");
+  str = gsk_path_to_string (path);
+  /* Put each command on a new line */
+  for (s = str; *s; s++)
+    {
+      if (*s == ' ' &&
+          (s[1] == 'M' || s[1] == 'C' || s[1] == 'Z' || s[1] == 'L' || s[1] == 'O'))
+        *s = '\n';
+    }
+  append_escaping_newlines (p->str, str);
+  g_string_append (p->str, "\";\n");
+  g_free (str);
+}
+
+static void
+append_dash_param (Printer     *p,
+                   const char  *param_name,
+                   const float *dash,
+                   gsize        n_dash)
+{
+  _indent (p);
+  g_string_append (p->str, "dash: ");
+
+  if (n_dash == 0)
+    {
+      g_string_append (p->str, "none");
+    }
+  else
+    {
+      gsize i;
+
+      string_append_double (p->str, dash[0]);
+      for (i = 1; i < n_dash; i++)
+        {
+          g_string_append_c (p->str, ' ');
+          string_append_double (p->str, dash[i]);
+        }
+    }
+
+  g_string_append (p->str, ";\n");
+}
+
 static void
 render_node_print (Printer       *p,
                    GskRenderNode *node)
@@ -2539,6 +2850,42 @@ render_node_print (Printer       *p,
         append_rounded_rect_param (p, "clip", gsk_rounded_clip_node_get_clip (node));
         append_node_param (p, "child", gsk_rounded_clip_node_get_child (node));
 
+        end_node (p);
+      }
+      break;
+
+    case GSK_FILL_NODE:
+      {
+        start_node (p, "fill");
+
+        append_node_param (p, "child", gsk_fill_node_get_child (node));
+        append_path_param (p, "path", gsk_fill_node_get_path (node));
+        append_enum_param (p, "fill-rule", GSK_TYPE_FILL_RULE, gsk_fill_node_get_fill_rule (node));
+
+        end_node (p);
+      }
+      break;
+
+    case GSK_STROKE_NODE:
+      {
+        const GskStroke *stroke;
+        const float *dash;
+        gsize n_dash;
+
+        start_node (p, "stroke");
+
+        append_node_param (p, "child", gsk_stroke_node_get_child (node));
+        append_path_param (p, "path", gsk_stroke_node_get_path (node));
+
+        stroke = gsk_stroke_node_get_stroke (node);
+        append_float_param (p, "line-width", gsk_stroke_get_line_width (stroke), 0.0f);
+        append_enum_param (p, "line-cap", GSK_TYPE_LINE_CAP, gsk_stroke_get_line_cap (stroke));
+        append_enum_param (p, "line-join", GSK_TYPE_LINE_JOIN, gsk_stroke_get_line_join (stroke));
+        append_float_param (p, "miter-limit", gsk_stroke_get_miter_limit (stroke), 4.0f);
+        dash = gsk_stroke_get_dash (stroke, &n_dash);
+        if (dash)
+          append_dash_param (p, "dash", dash, n_dash);
+        append_float_param (p, "dash-offset", gsk_stroke_get_dash_offset (stroke), 0.0f);
 
         end_node (p);
       }
@@ -3045,3 +3392,4 @@ gsk_render_node_serialize (GskRenderNode *node)
 
   return g_string_free_to_bytes (p.str);
 }
+

gsk/gskspline.c

@@ -0,0 +1,208 @@
+/*
+ * Copyright © 2002 University of Southern California
+ *             2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ *          Carl D. Worth <cworth@cworth.org>
+ */
+
+#include "config.h"
+
+#include "gsksplineprivate.h"
+
+#include <math.h>
+
+/* Spline deviation from the circle in radius would be given by:
+
+        error = sqrt (x**2 + y**2) - 1
+
+   A simpler error function to work with is:
+
+        e = x**2 + y**2 - 1
+
+   From "Good approximation of circles by curvature-continuous Bezier
+   curves", Tor Dokken and Morten Daehlen, Computer Aided Geometric
+   Design 8 (1990) 22-41, we learn:
+
+        abs (max(e)) = 4/27 * sin**6(angle/4) / cos**2(angle/4)
+
+   and
+        abs (error) =~ 1/2 * e
+
+   Of course, this error value applies only for the particular spline
+   approximation that is used in _cairo_gstate_arc_segment.
+*/
+static float
+arc_error_normalized (float angle)
+{
+  return 2.0/27.0 * pow (sin (angle / 4), 6) / pow (cos (angle / 4), 2);
+}
+
+static float
+arc_max_angle_for_tolerance_normalized (float tolerance)
+{
+  float angle, error;
+  guint i;
+
+  /* Use table lookup to reduce search time in most cases. */
+  struct {
+    float angle;
+    float error;
+  } table[] = {
+    { G_PI / 1.0,   0.0185185185185185036127 },
+    { G_PI / 2.0,   0.000272567143730179811158 },
+    { G_PI / 3.0,   2.38647043651461047433e-05 },
+    { G_PI / 4.0,   4.2455377443222443279e-06 },
+    { G_PI / 5.0,   1.11281001494389081528e-06 },
+    { G_PI / 6.0,   3.72662000942734705475e-07 },
+    { G_PI / 7.0,   1.47783685574284411325e-07 },
+    { G_PI / 8.0,   6.63240432022601149057e-08 },
+    { G_PI / 9.0,   3.2715520137536980553e-08 },
+    { G_PI / 10.0,  1.73863223499021216974e-08 },
+    { G_PI / 11.0,  9.81410988043554039085e-09 },
+  };
+
+  for (i = 0; i < G_N_ELEMENTS (table); i++)
+    {
+      if (table[i].error < tolerance)
+        return table[i].angle;
+    }
+
+  i++;
+  do {
+    angle = G_PI / i++;
+    error = arc_error_normalized (angle);
+  } while (error > tolerance);
+
+  return angle;
+}
+
+static guint
+arc_segments_needed (float angle,
+                     float radius,
+                     float tolerance)
+{
+  float max_angle;
+
+  /* the error is amplified by at most the length of the
+   * major axis of the circle; see cairo-pen.c for a more detailed analysis
+   * of this. */
+  max_angle = arc_max_angle_for_tolerance_normalized (tolerance / radius);
+
+  return ceil (fabs (angle) / max_angle);
+}
+
+/* We want to draw a single spline approximating a circular arc radius
+   R from angle A to angle B. Since we want a symmetric spline that
+   matches the endpoints of the arc in position and slope, we know
+   that the spline control points must be:
+
+        (R * cos(A), R * sin(A))
+        (R * cos(A) - h * sin(A), R * sin(A) + h * cos (A))
+        (R * cos(B) + h * sin(B), R * sin(B) - h * cos (B))
+        (R * cos(B), R * sin(B))
+
+   for some value of h.
+
+   "Approximation of circular arcs by cubic polynomials", Michael
+   Goldapp, Computer Aided Geometric Design 8 (1991) 227-238, provides
+   various values of h along with error analysis for each.
+
+   From that paper, a very practical value of h is:
+
+        h = 4/3 * R * tan(angle/4)
+
+   This value does not give the spline with minimal error, but it does
+   provide a very good approximation, (6th-order convergence), and the
+   error expression is quite simple, (see the comment for
+   _arc_error_normalized).
+*/
+static gboolean
+gsk_spline_decompose_arc_segment (const graphene_point_t *center,
+                                  float                   radius,
+                                  float                   angle_A,
+                                  float                   angle_B,
+                                  GskSplineAddCurveFunc   curve_func,
+                                  gpointer                user_data)
+{
+  float r_sin_A, r_cos_A;
+  float r_sin_B, r_cos_B;
+  float h;
+
+  r_sin_A = radius * sin (angle_A);
+  r_cos_A = radius * cos (angle_A);
+  r_sin_B = radius * sin (angle_B);
+  r_cos_B = radius * cos (angle_B);
+
+  h = 4.0/3.0 * tan ((angle_B - angle_A) / 4.0);
+
+  return curve_func ((graphene_point_t[4]) {
+                       GRAPHENE_POINT_INIT (
+                         center->x + r_cos_A,
+                         center->y + r_sin_A
+                       ),
+                       GRAPHENE_POINT_INIT (
+                         center->x + r_cos_A - h * r_sin_A,
+                         center->y + r_sin_A + h * r_cos_A
+                       ),
+                       GRAPHENE_POINT_INIT (
+                         center->x + r_cos_B + h * r_sin_B,
+                         center->y + r_sin_B - h * r_cos_B
+                       ),
+                       GRAPHENE_POINT_INIT (
+                         center->x + r_cos_B,
+                         center->y + r_sin_B
+                       )
+                     },
+                     user_data);
+}
+
+gboolean
+gsk_spline_decompose_arc (const graphene_point_t *center,
+                          float                   radius,
+                          float                   tolerance,
+                          float                   start_angle,
+                          float                   end_angle,
+                          GskSplineAddCurveFunc   curve_func,
+                          gpointer                user_data)
+{
+  float step = start_angle - end_angle;
+  guint i, n_segments;
+
+  /* Recurse if drawing arc larger than pi */
+  if (ABS (step) > G_PI)
+    {
+      float mid_angle = (start_angle + end_angle) / 2.0;
+
+      return gsk_spline_decompose_arc (center, radius, tolerance, start_angle, mid_angle, curve_func, user_data)
+          && gsk_spline_decompose_arc (center, radius, tolerance, mid_angle, end_angle, curve_func, user_data);
+    }
+  else if (ABS (step) < tolerance)
+    {
+      return gsk_spline_decompose_arc_segment (center, radius, start_angle, end_angle, curve_func, user_data);
+    }
+
+  n_segments = arc_segments_needed (ABS (step), radius, tolerance);
+  step = (end_angle - start_angle) / n_segments;
+
+  for (i = 0; i < n_segments - 1; i++, start_angle += step)
+    {
+      if (!gsk_spline_decompose_arc_segment (center, radius, start_angle, start_angle + step, curve_func, user_data))
+        return FALSE;
+    }
+  return gsk_spline_decompose_arc_segment (center, radius, start_angle, end_angle, curve_func, user_data);
+}
+

gsk/gsksplineprivate.h

@@ -0,0 +1,41 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+
+#ifndef __GSK_SPLINE_PRIVATE_H__
+#define __GSK_SPLINE_PRIVATE_H__
+
+#include "gskpath.h"
+
+G_BEGIN_DECLS
+
+typedef gboolean (* GskSplineAddCurveFunc) (const graphene_point_t curve[4],
+                                            gpointer               user_data);
+gboolean                gsk_spline_decompose_arc                (const graphene_point_t *center,
+                                                                 float                   radius,
+                                                                 float                   tolerance,
+                                                                 float                   start_angle,
+                                                                 float                   end_angle,
+                                                                 GskSplineAddCurveFunc   curve_func,
+                                                                 gpointer                user_data);
+
+G_END_DECLS
+
+#endif /* __GSK_SPLINE_PRIVATE_H__ */
+

gsk/gskstroke.c

@@ -0,0 +1,458 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#include "config.h"
+
+#include "gskstrokeprivate.h"
+
+/**
+ * GskStroke:
+ *
+ * A `GskStroke` describes the attributes that are used when stroking a path.
+ */
+
+G_DEFINE_BOXED_TYPE (GskStroke, gsk_stroke,
+                     gsk_stroke_copy,
+                     gsk_stroke_free)
+
+
+/**
+ * gsk_stroke_new:
+ * @line_width: line width of the stroke. Must be > 0
+ *
+ * Creates a new `GskStroke` with the given @line_width.
+ *
+ * Returns: a new `GskStroke`
+ **/
+GskStroke *
+gsk_stroke_new (float line_width)
+{
+  GskStroke *self;
+
+  g_return_val_if_fail (line_width > 0, NULL);
+
+  self = g_new0 (GskStroke, 1);
+
+  self->line_width = line_width;
+  self->line_cap = GSK_LINE_CAP_BUTT;
+  self->line_join = GSK_LINE_JOIN_MITER;
+  self->miter_limit = 4.f; /* following svg */
+
+  return self;
+}
+
+/**
+ * gsk_stroke_copy:
+ * @other: `GskStroke` to copy
+ *
+ * Creates a copy of the given @other stroke.
+ *
+ * Returns: a new `GskStroke`. Use [method@Gsk.Stroke.free] to free it.
+ **/
+GskStroke *
+gsk_stroke_copy (const GskStroke *other)
+{
+  GskStroke *self;
+
+  g_return_val_if_fail (other != NULL, NULL);
+
+  self = g_new (GskStroke, 1);
+
+  gsk_stroke_init_copy (self, other);
+
+  return self;
+}
+
+/**
+ * gsk_stroke_free:
+ * @self: a `GskStroke`
+ *
+ * Frees a `GskStroke`.
+ **/
+void
+gsk_stroke_free (GskStroke *self)
+{
+  if (self == NULL)
+    return;
+
+  gsk_stroke_clear (self);
+
+  g_free (self);
+}
+
+/**
+ * gsk_stroke_to_cairo:
+ * @self: a #GskStroke
+ * @cr: the cairo context to configure
+ *
+ * A helper function that sets the stroke parameters
+ * of @cr from the values found in @self.
+ */
+void
+gsk_stroke_to_cairo (const GskStroke *self,
+                     cairo_t         *cr)
+{
+  cairo_set_line_width (cr, self->line_width);
+
+  /* gcc can optimize that to a direct case. This catches later additions to the enum */
+  switch (self->line_cap)
+    {
+      case GSK_LINE_CAP_BUTT:
+        cairo_set_line_cap (cr, CAIRO_LINE_CAP_BUTT);
+        break;
+      case GSK_LINE_CAP_ROUND:
+        cairo_set_line_cap (cr, CAIRO_LINE_CAP_ROUND);
+        break;
+      case GSK_LINE_CAP_SQUARE:
+        cairo_set_line_cap (cr, CAIRO_LINE_CAP_SQUARE);
+        break;
+      default:
+        g_assert_not_reached ();
+        break;
+    }
+
+  /* gcc can optimize that to a direct case. This catches later additions to the enum */
+  switch (self->line_join)
+    {
+      case GSK_LINE_JOIN_MITER:
+      case GSK_LINE_JOIN_MITER_CLIP:
+      case GSK_LINE_JOIN_ARCS:
+        cairo_set_line_join (cr, CAIRO_LINE_JOIN_MITER);
+        break;
+      case GSK_LINE_JOIN_ROUND:
+        cairo_set_line_join (cr, CAIRO_LINE_JOIN_ROUND);
+        break;
+      case GSK_LINE_JOIN_BEVEL:
+        cairo_set_line_join (cr, CAIRO_LINE_JOIN_BEVEL);
+        break;
+      default:
+        g_assert_not_reached ();
+        break;
+    }
+
+  cairo_set_miter_limit (cr, self->miter_limit);
+
+  if (self->dash_length)
+    {
+      gsize i;
+      double *dash = g_newa (double, self->n_dash);
+
+      for (i = 0; i < self->n_dash; i++)
+        {
+          dash[i] = self->dash[i];
+        }
+      cairo_set_dash (cr, dash, self->n_dash, self->dash_offset);
+    }
+  else
+    cairo_set_dash (cr, NULL, 0, 0.0);
+}
+
+/**
+ * gsk_stroke_equal:
+ * @stroke1: the first `GskStroke`
+ * @stroke2: the second `GskStroke`
+ *
+ * Checks if two strokes are identical.
+ *
+ * Returns: %TRUE if the two strokes are equal, %FALSE otherwise
+ **/
+gboolean
+gsk_stroke_equal (gconstpointer stroke1,
+                  gconstpointer stroke2)
+{
+  const GskStroke *self1 = stroke1;
+  const GskStroke *self2 = stroke2;
+
+  if (self1->line_width != self2->line_width ||
+      self1->line_cap != self2->line_cap ||
+      self1->line_join != self2->line_join ||
+      self1->miter_limit != self2->miter_limit)
+    return FALSE;
+
+  if (self1->n_dash != self2->n_dash)
+    return FALSE;
+
+  for (int i = 0; i < self1->n_dash; i++)
+    {
+      if (self1->dash[i] != self2->dash[i])
+        return FALSE;
+    }
+
+  if (self1->dash_offset != self2->dash_offset)
+    return FALSE;
+
+  return TRUE;
+}
+
+/**
+ * gsk_stroke_set_line_width:
+ * @self: a `GskStroke`
+ * @line_width: width of the line in pixels
+ *
+ * Sets the line width to be used when stroking.
+ *
+ * The line width must be > 0.
+ **/
+void
+gsk_stroke_set_line_width (GskStroke *self,
+                           float      line_width)
+{
+  g_return_if_fail (self != NULL);
+  g_return_if_fail (line_width > 0);
+
+  self->line_width = line_width;
+}
+
+/**
+ * gsk_stroke_get_line_width:
+ * @self: a `GskStroke`
+ *
+ * Gets the line width used.
+ *
+ * Returns: The line width
+ **/
+float
+gsk_stroke_get_line_width (const GskStroke *self)
+{
+  g_return_val_if_fail (self != NULL, 0.0);
+
+  return self->line_width;
+}
+
+/**
+ * gsk_stroke_set_line_cap:
+ * @self: a `GskStroke`
+ * @line_cap: the `GskLineCap`
+ *
+ * Sets the line cap to be used when stroking.
+ *
+ * See `GskLineCap` for details.
+ **/
+void
+gsk_stroke_set_line_cap (GskStroke  *self,
+                         GskLineCap  line_cap)
+{
+  g_return_if_fail (self != NULL);
+
+  self->line_cap = line_cap;
+}
+
+/**
+ * gsk_stroke_get_line_cap:
+ * @self: a `GskStroke`
+ *
+ * Gets the line cap used.
+ *
+ * See `GskLineCap` for details.
+ *
+ * Returns: The line cap
+ **/
+GskLineCap
+gsk_stroke_get_line_cap (const GskStroke *self)
+{
+  g_return_val_if_fail (self != NULL, 0.0);
+
+  return self->line_cap;
+}
+
+/**
+ * gsk_stroke_set_line_join:
+ * @self: a `GskStroke`
+ * @line_join: The line join to use
+ *
+ * Sets the line join to be used when stroking.
+ *
+ * See `GskLineJoin` for details.
+ **/
+void
+gsk_stroke_set_line_join (GskStroke   *self,
+                          GskLineJoin  line_join)
+{
+  g_return_if_fail (self != NULL);
+
+  self->line_join = line_join;
+}
+
+/**
+ * gsk_stroke_get_line_join:
+ * @self: a `GskStroke`
+ *
+ * Gets the line join used.
+ *
+ * See `GskLineJoin` for details.
+ *
+ * Returns: The line join
+ **/
+GskLineJoin
+gsk_stroke_get_line_join (const GskStroke *self)
+{
+  g_return_val_if_fail (self != NULL, 0.0);
+
+  return self->line_join;
+}
+
+/**
+ * gsk_stroke_set_miter_limit:
+ * @self: a `GskStroke`
+ * @limit: the miter limit, must be non-negative
+ *
+ * Sets the limit for the distance from the corner where sharp
+ * turns of joins get cut off. The miter limit is in units of
+ * line width.
+ *
+ * For joins of type `GSK_LINE_JOIN_MITER` that exceed the miter
+ * limit, the join gets rendered as if it was of type
+ * `GSK_LINE_JOIN_BEVEL`. For joins of type `GSK_LINE_JOIN_MITER_CLIP`,
+ * the miter is clipped at a distance of half the miter limit.
+ */
+void
+gsk_stroke_set_miter_limit (GskStroke  *self,
+                            float       limit)
+{
+  g_return_if_fail (self != NULL);
+  g_return_if_fail (limit >= 0);
+
+  self->miter_limit = limit;
+}
+
+/**
+ * gsk_stroke_get_miter_limit:
+ * @self: a `GskStroke`
+ *
+ * Returns the miter limit of a `GskStroke`.
+ */
+float
+gsk_stroke_get_miter_limit (const GskStroke *self)
+{
+  g_return_val_if_fail (self != NULL, 4.f);
+
+  return self->miter_limit;
+}
+
+/**
+ * gsk_stroke_set_dash:
+ * @self: a `GskStroke`
+ * @dash: (array length=n_dash) (transfer none) (allow-none): the array of dashes
+ * @n_dash: number of elements in @dash
+ *
+ * Sets the dash pattern to use by this stroke. A dash pattern is specified by
+ * an array of alternating non-negative values. Each value provides the length
+ * of alternate "on" and "off" portions of the stroke.
+ *
+ * Each "on" segment will have caps applied as if the segment were a separate
+ * contour. In particular, it is valid to use an "on" length of 0 with
+ * `GSK_LINE_CAP_ROUND` or `GSK_LINE_CAP_SQUARE` to draw dots or squares along
+ * a path.
+ *
+ * If @n_dash is 0, if all elements in @dash are 0, or if there are negative
+ * values in @dash, then dashing is disabled.
+ *
+ * If @n_dash is 1, an alternating "on" and "off" pattern with the single
+ * dash length provided is assumed.
+ *
+ * If @n_dash is uneven, the dash array will be used with the first element
+ * in @dash defining an "on" or "off" in alternating passes through the array.
+ *
+ * You can specify a starting offset into the dash with [method@Gsk.Stroke.set_dash_offset].
+ **/
+void
+gsk_stroke_set_dash (GskStroke   *self,
+                     const float *dash,
+                     gsize        n_dash)
+{
+  float dash_length;
+  gsize i;
+
+  g_return_if_fail (self != NULL);
+  g_return_if_fail (dash != NULL || n_dash == 0);
+
+  dash_length = 0;
+  for (i = 0; i < n_dash; i++)
+    {
+      if (!(dash[i] >= 0)) /* should catch NaN */
+        {
+          g_critical ("invalid value in dash array at position %zu", i);
+          return;
+        }
+      dash_length += dash[i];
+    }
+
+  self->dash_length = dash_length;
+  g_free (self->dash);
+  self->dash = g_memdup (dash, sizeof (gfloat) * n_dash);
+  self->n_dash = n_dash;
+
+}
+
+/**
+ * gsk_stroke_get_dash:
+ * @self: a `GskStroke`
+ * @n_dash: (out caller-allocates): number of elements
+ *   in the array returned
+ *
+ * Gets the dash array in use or %NULL if dashing is disabled.
+ *
+ * Returns: (array length=n_dash) (transfer none) (allow-none):
+ *   The dash array or %NULL if the dash array is empty.
+ **/
+const float *
+gsk_stroke_get_dash (const GskStroke *self,
+                     gsize           *n_dash)
+{
+  g_return_val_if_fail (self != NULL, NULL);
+  g_return_val_if_fail (n_dash != NULL, NULL);
+
+  *n_dash = self->n_dash;
+
+  return self->dash;
+}
+
+/**
+ * gsk_stroke_set_dash_offset:
+ * @self: a `GskStroke`
+ * @offset: offset into the dash pattern
+ *
+ * Sets the offset into the dash pattern set via [method@Gsk.Stroke.set_dash]
+ * where dashing should begin.
+ *
+ * This is an offset into the length of the path, not an index into
+ * the array values of the dash array.
+ **/
+void
+gsk_stroke_set_dash_offset (GskStroke *self,
+                            float      offset)
+{
+  g_return_if_fail (self != NULL);
+
+  self->dash_offset = offset;
+}
+
+/**
+ * gsk_stroke_get_dash_offset:
+ * @self: a `GskStroke`
+ *
+ * Returns the dash offset of a `GskStroke`.
+ */
+float
+gsk_stroke_get_dash_offset (const GskStroke *self)
+{
+  g_return_val_if_fail (self != NULL, 4.f);
+
+  return self->dash_offset;
+}

gsk/gskstroke.h

@@ -0,0 +1,91 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#ifndef __GSK_STROKE_H__
+#define __GSK_STROKE_H__
+
+#if !defined (__GSK_H_INSIDE__) && !defined (GTK_COMPILATION)
+#error "Only <gsk/gsk.h> can be included directly."
+#endif
+
+
+#include <gsk/gsktypes.h>
+
+G_BEGIN_DECLS
+
+#define GSK_TYPE_STROKE (gsk_stroke_get_type ())
+
+GDK_AVAILABLE_IN_ALL
+GType                   gsk_stroke_get_type                     (void) G_GNUC_CONST;
+GDK_AVAILABLE_IN_ALL
+GskStroke *             gsk_stroke_new                          (float                   line_width);
+GDK_AVAILABLE_IN_ALL
+GskStroke *             gsk_stroke_copy                         (const GskStroke        *other);
+GDK_AVAILABLE_IN_ALL
+void                    gsk_stroke_free                         (GskStroke              *self);
+
+GDK_AVAILABLE_IN_ALL
+gboolean                gsk_stroke_equal                        (gconstpointer           stroke1,
+                                                                 gconstpointer           stroke2);
+
+GDK_AVAILABLE_IN_ALL
+void                    gsk_stroke_set_line_width               (GskStroke              *self,
+                                                                 float                   line_width);
+GDK_AVAILABLE_IN_ALL
+float                   gsk_stroke_get_line_width               (const GskStroke        *self);
+GDK_AVAILABLE_IN_ALL
+void                    gsk_stroke_set_line_cap                 (GskStroke              *self,
+                                                                 GskLineCap              line_cap);
+GDK_AVAILABLE_IN_ALL
+GskLineCap              gsk_stroke_get_line_cap                 (const GskStroke        *self);
+GDK_AVAILABLE_IN_ALL
+void                    gsk_stroke_set_line_join                (GskStroke              *self,
+                                                                 GskLineJoin             line_join);
+GDK_AVAILABLE_IN_ALL
+GskLineJoin             gsk_stroke_get_line_join                (const GskStroke        *self);
+
+GDK_AVAILABLE_IN_ALL
+void                    gsk_stroke_set_miter_limit              (GskStroke              *self,
+                                                                 float                   limit);
+GDK_AVAILABLE_IN_ALL
+float                   gsk_stroke_get_miter_limit              (const GskStroke        *self);
+
+GDK_AVAILABLE_IN_ALL
+void                    gsk_stroke_set_dash                     (GskStroke              *self,
+                                                                 const float            *dash,
+                                                                 gsize                   n_dash);
+GDK_AVAILABLE_IN_ALL
+const float *           gsk_stroke_get_dash                     (const GskStroke        *self,
+                                                                 gsize                  *n_dash);
+
+GDK_AVAILABLE_IN_ALL
+void                    gsk_stroke_set_dash_offset              (GskStroke              *self,
+                                                                 float                   offset);
+GDK_AVAILABLE_IN_ALL
+float                   gsk_stroke_get_dash_offset              (const GskStroke        *self);
+
+GDK_AVAILABLE_IN_ALL
+void                    gsk_stroke_to_cairo                     (const GskStroke        *self,
+                                                                 cairo_t                *cr);
+
+
+
+G_END_DECLS
+
+#endif /* __GSK_STROKE_H__ */

gsk/gskstrokeprivate.h

@@ -0,0 +1,60 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+
+#ifndef __GSK_STROKE_PRIVATE_H__
+#define __GSK_STROKE_PRIVATE_H__
+
+#include "gskstroke.h"
+
+G_BEGIN_DECLS
+
+struct _GskStroke
+{
+  float line_width;
+  GskLineCap line_cap;
+  GskLineJoin line_join;
+  float miter_limit;
+
+  float *dash;
+  gsize n_dash;
+  float dash_length; /* sum of all dashes in the array */
+  float dash_offset;
+};
+
+static inline void
+gsk_stroke_init_copy (GskStroke       *stroke,
+                      const GskStroke *other)
+{
+  *stroke = *other;
+
+  stroke->dash = g_memdup (other->dash, stroke->n_dash * sizeof (float));
+}
+
+static inline void
+gsk_stroke_clear (GskStroke *stroke)
+{
+  g_clear_pointer (&stroke->dash, g_free);
+  stroke->n_dash = 0; /* better safe than sorry */
+}
+
+G_END_DECLS
+
+#endif /* __GSK_STROKE_PRIVATE_H__ */
+

gsk/gsktypes.h

@@ -26,7 +26,11 @@
 #include <gdk/gdk.h>
 #include <gsk/gskenums.h>
 
+typedef struct _GskPath                 GskPath;
+typedef struct _GskPathBuilder          GskPathBuilder;
+typedef struct _GskPathMeasure          GskPathMeasure;
 typedef struct _GskRenderer             GskRenderer;
+typedef struct _GskStroke               GskStroke;
 typedef struct _GskTransform            GskTransform;
 
 #endif /* __GSK_TYPES_H__ */

gsk/meson.build

@@ -22,27 +22,41 @@ gsk_private_gl_shaders = [
 ]
 
 gsk_public_sources = files([
-  'gskdiff.c',
   'gskcairorenderer.c',
+  'gskdiff.c',
   'gskglshader.c',
+  'gskpath.c',
+  'gskpathbuilder.c',
+  'gskpathdash.c',
+  'gskpathmeasure.c',
+  'gskpathops.c',
+  'gskpathstroke.c',
   'gskrenderer.c',
   'gskrendernode.c',
   'gskrendernodeimpl.c',
   'gskrendernodeparser.c',
   'gskroundedrect.c',
+  'gskstroke.c',
   'gsktransform.c',
   'gl/gskglrenderer.c',
 ])
 
 gsk_private_sources = files([
+  'gskboundingbox.c',
   'gskcairoblur.c',
+  'gskcontour.c',
+  'gskconvexity.c',
+  'gskcurve.c',
+  'gskcurveintersect.c',
   'gskdebug.c',
   'gskprivate.c',
   'gskprofiler.c',
+  'gskspline.c',
   'gl/gskglattachmentstate.c',
   'gl/gskglbuffer.c',
   'gl/gskglcommandqueue.c',
   'gl/gskglcompiler.c',
+  'gl/gskglprofiler.c',
   'gl/gskgldriver.c',
   'gl/gskglglyphlibrary.c',
   'gl/gskgliconlibrary.c',
@@ -65,9 +79,13 @@ gsk_public_headers = files([
   'gskcairorenderer.h',
   'gskenums.h',
   'gskglshader.h',
+  'gskpath.h',
+  'gskpathbuilder.h',
+  'gskpathmeasure.h',
   'gskrenderer.h',
   'gskrendernode.h',
   'gskroundedrect.h',
+  'gskstroke.h',
   'gsktransform.h',
   'gsktypes.h',
   'gsk-autocleanup.h',

gsk/vulkan/gskvulkanrenderpass.c

@@ -260,6 +260,8 @@ gsk_vulkan_render_pass_add_node (GskVulkanRenderPass           *self,
     case GSK_RADIAL_GRADIENT_NODE:
     case GSK_REPEATING_RADIAL_GRADIENT_NODE:
     case GSK_CONIC_GRADIENT_NODE:
+    case GSK_FILL_NODE:
+    case GSK_STROKE_NODE:
     default:
       FALLBACK ("Unsupported node '%s'", g_type_name_from_instance ((GTypeInstance *) node));
 

gtk/gtkpopover.c

@@ -1289,6 +1289,28 @@ get_border (GtkCssNode *node,
   border->left = _gtk_css_number_value_get (style->border->border_left_width, 100);
 }
 
+static GskPath *
+gtk_popover_get_tail_path (GtkPopover *popover)
+{
+  GskPathBuilder *builder;
+  int initial_x, initial_y;
+  int tip_x, tip_y;
+  int final_x, final_y;
+
+  builder = gsk_path_builder_new ();
+
+  gtk_popover_get_gap_coords (popover,
+                              &initial_x, &initial_y,
+                              &tip_x, &tip_y,
+                              &final_x, &final_y);
+
+  gsk_path_builder_move_to (builder, initial_x, initial_y);
+  gsk_path_builder_line_to (builder, tip_x, tip_y);
+  gsk_path_builder_line_to (builder, final_x, final_y);
+
+  return gsk_path_builder_free_to_path (builder);
+}
+
 static void
 gtk_popover_apply_tail_path (GtkPopover *popover,
                              cairo_t    *cr)
@@ -1543,22 +1565,14 @@ create_arrow_render_node (GtkPopover *popover)
   GtkWidget *widget = GTK_WIDGET (popover);
   GtkStyleContext *context;
   GtkBorder border;
-  cairo_t *cr;
   GtkSnapshot *snapshot;
+  GskPath *path;
 
   snapshot = gtk_snapshot_new ();
 
-  cr = gtk_snapshot_append_cairo (snapshot,
-                                  &GRAPHENE_RECT_INIT (
-                                    0, 0,
-                                    gtk_widget_get_width (widget),
-                                    gtk_widget_get_height (widget)
-                                  ));
-
   /* Clip to the arrow shape */
-  cairo_save (cr);
-  gtk_popover_apply_tail_path (popover, cr);
-  cairo_clip (cr);
+  path = gtk_popover_get_tail_path (popover);
+  gtk_snapshot_push_fill (snapshot, path, GSK_FILL_RULE_WINDING);
 
   get_border (priv->arrow_node, &border);
 
@@ -1566,29 +1580,34 @@ create_arrow_render_node (GtkPopover *popover)
   gtk_style_context_save_to_node (context, priv->arrow_node);
 
   /* Render the arrow background */
-  gtk_render_background (context, cr,
-                         0, 0,
-                         gtk_widget_get_width (widget),
-                         gtk_widget_get_height (widget));
+  gtk_snapshot_render_background (snapshot, context,
+                                  0, 0,
+                                  gtk_widget_get_width (widget),
+                                  gtk_widget_get_height (widget));
 
   /* Render the border of the arrow tip */
   if (border.bottom > 0)
     {
       GtkCssStyle *style;
       const GdkRGBA *border_color;
+      GskStroke *stroke;
+      graphene_rect_t bounds;
 
       style = gtk_css_node_get_style (priv->arrow_node);
       border_color = gtk_css_color_value_get_rgba (style->border->border_left_color ? style->border->border_left_color : style->core->color);
 
-      gtk_popover_apply_tail_path (popover, cr);
-      gdk_cairo_set_source_rgba (cr, border_color);
+      stroke = gsk_stroke_new (border.bottom + 1);
+      gtk_snapshot_push_stroke (snapshot, path, stroke);
+      gsk_stroke_free (stroke);
 
-      cairo_set_line_width (cr, border.bottom + 1);
-      cairo_stroke (cr);
+      gsk_path_get_bounds (path, &bounds);
+      gtk_snapshot_append_color (snapshot, border_color, &bounds);
+
+      gtk_snapshot_pop (snapshot);
     }
 
-  cairo_restore (cr);
-  cairo_destroy (cr);
+  gtk_snapshot_pop (snapshot);
+  gsk_path_unref (path);
 
   gtk_style_context_restore (context);
 

gtk/gtkrenderborder.c

@@ -357,16 +357,16 @@ snapshot_frame_fill (GtkSnapshot          *snapshot,
   gtk_snapshot_append_border (snapshot, outline, border_width, colors);
 }
 
-static void
-set_stroke_style (cairo_t        *cr,
-                  double          line_width,
-                  GtkBorderStyle  style,
-                  double          length)
+static GskStroke *
+create_stroke_style (double          line_width,
+                     GtkBorderStyle  style,
+                     double          length)
 {
-  double segments[2];
+  GskStroke *stroke;
+  float segments[2];
   double n;
 
-  cairo_set_line_width (cr, line_width);
+  stroke = gsk_stroke_new (line_width);
 
   if (style == GTK_BORDER_STYLE_DOTTED)
     {
@@ -374,12 +374,12 @@ set_stroke_style (cairo_t        *cr,
 
       segments[0] = 0;
       segments[1] = n ? length / n : 2;
-      cairo_set_dash (cr, segments, G_N_ELEMENTS (segments), 0);
+      gsk_stroke_set_dash (stroke, segments, 2);
 
-      cairo_set_line_cap (cr, CAIRO_LINE_CAP_ROUND);
-      cairo_set_line_join (cr, CAIRO_LINE_JOIN_ROUND);
+      gsk_stroke_set_line_cap (stroke, GSK_LINE_CAP_ROUND);
+      gsk_stroke_set_line_join (stroke, GSK_LINE_JOIN_ROUND);
     }
-  else
+  else if (style == GTK_BORDER_STYLE_DASHED)
     {
       n = length / line_width;
       /* Optimize the common case of an integer-sized rectangle
@@ -397,32 +397,33 @@ set_stroke_style (cairo_t        *cr,
           segments[0] = n ? (1. / 3) * length / n : 1;
           segments[1] = 2 * segments[0];
         }
-      cairo_set_dash (cr, segments, G_N_ELEMENTS (segments), 0);
+      gsk_stroke_set_dash (stroke, segments, 2);
 
-      cairo_set_line_cap (cr, CAIRO_LINE_CAP_SQUARE);
-      cairo_set_line_join (cr, CAIRO_LINE_JOIN_MITER);
+      gsk_stroke_set_line_cap (stroke, GSK_LINE_CAP_SQUARE);
+      gsk_stroke_set_line_join (stroke, GSK_LINE_JOIN_MITER);
     }
+  else
+    {
+      g_assert_not_reached ();
+    }
+
+  return stroke;
 }
 
 static void
-render_frame_stroke (cairo_t              *cr,
-                     const GskRoundedRect *border_box,
-                     const double          border_width[4],
-                     GdkRGBA               colors[4],
-                     guint                 hidden_side,
-                     GtkBorderStyle        stroke_style)
+snapshot_frame_stroke (GtkSnapshot          *snapshot,
+                       const GskRoundedRect *border_box,
+                       const float           border_width[4],
+                       GdkRGBA               colors[4],
+                       guint                 hidden_side,
+                       GtkBorderStyle        stroke_style)
 {
-  gboolean different_colors, different_borders;
   GskRoundedRect stroke_box;
+  GskPathBuilder *builder;
+  GskPath *path;
+  GskStroke *stroke;
   guint i;
 
-  different_colors = !gdk_rgba_equal (&colors[0], &colors[1]) ||
-                     !gdk_rgba_equal (&colors[0], &colors[2]) ||
-                     !gdk_rgba_equal (&colors[0], &colors[3]);
-  different_borders = border_width[0] != border_width[1] ||
-                      border_width[0] != border_width[2] ||
-                      border_width[0] != border_width[3] ;
-
   stroke_box = *border_box;
   gsk_rounded_rect_shrink (&stroke_box,
                            border_width[GTK_CSS_TOP] / 2.0,
@@ -430,32 +431,36 @@ render_frame_stroke (cairo_t              *cr,
                            border_width[GTK_CSS_BOTTOM] / 2.0,
                            border_width[GTK_CSS_LEFT] / 2.0);
 
-  if (!different_colors && !different_borders && hidden_side == 0)
+  if (border_width[0] == border_width[1] &&
+      border_width[0] == border_width[2] &&
+      border_width[0] == border_width[3] &&
+      hidden_side == 0)
     {
       double length = 0;
 
       /* FAST PATH:
        * Mostly expected to trigger for focus rectangles */
-      for (i = 0; i < 4; i++) 
+      for (i = 0; i < 4; i++)
         {
           length += _gtk_rounded_box_guess_length (&stroke_box, i);
         }
 
-      gsk_rounded_rect_path (&stroke_box, cr);
-      gdk_cairo_set_source_rgba (cr, &colors[0]);
-      set_stroke_style (cr, border_width[0], stroke_style, length);
-      cairo_stroke (cr);
+      builder = gsk_path_builder_new ();
+      gsk_path_builder_add_rounded_rect (builder, &stroke_box);
+      path = gsk_path_builder_free_to_path (builder);
+      stroke = create_stroke_style (border_width[0],
+                                    stroke_style, length);
+      gtk_snapshot_push_stroke (snapshot, path, stroke);
+      gsk_stroke_free (stroke);
+      gsk_path_unref (path);
+
+      gtk_snapshot_append_border (snapshot, border_box, border_width, colors);
+
+      gtk_snapshot_pop (snapshot);
     }
   else
     {
-      GskRoundedRect padding_box;
-
-      padding_box = *border_box;
-      gsk_rounded_rect_shrink (&padding_box,
-                               border_width[GTK_CSS_TOP],
-                               border_width[GTK_CSS_RIGHT],
-                               border_width[GTK_CSS_BOTTOM],
-                               border_width[GTK_CSS_LEFT]);
+      const float weight = sqrtf(2)/2.0;
 
       for (i = 0; i < 4; i++)
         {
@@ -465,49 +470,111 @@ render_frame_stroke (cairo_t              *cr,
           if (border_width[i] == 0)
             continue;
 
-          cairo_save (cr);
-
+          builder = gsk_path_builder_new ();
           if (i == 0)
-            _gtk_rounded_box_path_top (border_box, &padding_box, cr);
+            {
+              /* top */
+              gsk_path_builder_move_to (builder,
+                                        stroke_box.bounds.origin.x + stroke_box.corner[GSK_CORNER_TOP_LEFT].width / 2,
+                                        stroke_box.bounds.origin.y + stroke_box.corner[GSK_CORNER_TOP_LEFT].height / 2);
+              gsk_path_builder_conic_to (builder,
+                                         stroke_box.bounds.origin.x,
+                                         stroke_box.bounds.origin.y,
+                                         stroke_box.bounds.origin.x + stroke_box.corner[GSK_CORNER_TOP_LEFT].width,
+                                         stroke_box.bounds.origin.y,
+                                         weight);
+              gsk_path_builder_line_to (builder,
+                                        stroke_box.bounds.origin.x + stroke_box.bounds.size.width - stroke_box.corner[GSK_CORNER_TOP_RIGHT].width,
+                                        stroke_box.bounds.origin.y);
+              gsk_path_builder_conic_to (builder,
+                                         stroke_box.bounds.origin.x + stroke_box.bounds.size.width,
+                                         stroke_box.bounds.origin.y,
+                                         stroke_box.bounds.origin.x + stroke_box.bounds.size.width - stroke_box.corner[GSK_CORNER_TOP_RIGHT].width / 2,
+                                         stroke_box.bounds.origin.y + stroke_box.corner[GSK_CORNER_TOP_RIGHT].height / 2,
+                                         weight);
+            }
           else if (i == 1)
-            _gtk_rounded_box_path_right (border_box, &padding_box, cr);
+            {
+              /* right */
+              gsk_path_builder_move_to (builder,
+                                        stroke_box.bounds.origin.x + stroke_box.bounds.size.width - stroke_box.corner[GSK_CORNER_TOP_RIGHT].width / 2,
+                                        stroke_box.bounds.origin.y + stroke_box.corner[GSK_CORNER_TOP_RIGHT].height / 2);
+              gsk_path_builder_conic_to (builder,
+                                         stroke_box.bounds.origin.x + stroke_box.bounds.size.width,
+                                         stroke_box.bounds.origin.y,
+                                         stroke_box.bounds.origin.x + stroke_box.bounds.size.width,
+                                         stroke_box.bounds.origin.y + stroke_box.corner[GSK_CORNER_TOP_RIGHT].height,
+                                         weight);
+              gsk_path_builder_line_to (builder,
+                                        stroke_box.bounds.origin.x + stroke_box.bounds.size.width,
+                                        stroke_box.bounds.origin.y + stroke_box.bounds.size.height - stroke_box.corner[GSK_CORNER_BOTTOM_RIGHT].height);
+              gsk_path_builder_conic_to (builder,
+                                         stroke_box.bounds.origin.x + stroke_box.bounds.size.width,
+                                         stroke_box.bounds.origin.y + stroke_box.bounds.size.height,
+                                         stroke_box.bounds.origin.x + stroke_box.bounds.size.width - stroke_box.corner[GSK_CORNER_BOTTOM_RIGHT].width / 2,
+                                         stroke_box.bounds.origin.y + stroke_box.bounds.size.height - stroke_box.corner[GSK_CORNER_BOTTOM_RIGHT].height / 2,
+                                         weight);
+            }
           else if (i == 2)
-            _gtk_rounded_box_path_bottom (border_box, &padding_box, cr);
+            {
+              /* bottom */
+              gsk_path_builder_move_to (builder,
+                                         stroke_box.bounds.origin.x + stroke_box.bounds.size.width - stroke_box.corner[GSK_CORNER_BOTTOM_RIGHT].width / 2,
+                                         stroke_box.bounds.origin.y + stroke_box.bounds.size.height - stroke_box.corner[GSK_CORNER_BOTTOM_RIGHT].height / 2);
+              gsk_path_builder_conic_to (builder,
+                                         stroke_box.bounds.origin.x + stroke_box.bounds.size.width,
+                                         stroke_box.bounds.origin.y + stroke_box.bounds.size.height,
+                                         stroke_box.bounds.origin.x + stroke_box.bounds.size.width - stroke_box.corner[GSK_CORNER_BOTTOM_RIGHT].width,
+                                         stroke_box.bounds.origin.y + stroke_box.bounds.size.height,
+                                         weight);
+              gsk_path_builder_line_to (builder,
+                                        stroke_box.bounds.origin.x + stroke_box.corner[GSK_CORNER_BOTTOM_LEFT].width,
+                                        stroke_box.bounds.origin.y + stroke_box.bounds.size.height);
+              gsk_path_builder_conic_to (builder,
+                                         stroke_box.bounds.origin.x,
+                                         stroke_box.bounds.origin.y + stroke_box.bounds.size.height,
+                                         stroke_box.bounds.origin.x + stroke_box.corner[GSK_CORNER_BOTTOM_LEFT].width / 2,
+                                         stroke_box.bounds.origin.y + stroke_box.bounds.size.height - stroke_box.corner[GSK_CORNER_BOTTOM_LEFT].height / 2,
+                                         weight);
+            }
           else if (i == 3)
-            _gtk_rounded_box_path_left (border_box, &padding_box, cr);
-          cairo_clip (cr);
+            {
+              /* left */
+              gsk_path_builder_move_to (builder,
+                                        stroke_box.bounds.origin.x + stroke_box.corner[GSK_CORNER_BOTTOM_LEFT].width / 2,
+                                        stroke_box.bounds.origin.y + stroke_box.bounds.size.height - stroke_box.corner[GSK_CORNER_BOTTOM_LEFT].height / 2);
+              gsk_path_builder_conic_to (builder,
+                                         stroke_box.bounds.origin.x,
+                                         stroke_box.bounds.origin.y + stroke_box.bounds.size.height,
+                                         stroke_box.bounds.origin.x,
+                                         stroke_box.bounds.origin.y + stroke_box.bounds.size.height - stroke_box.corner[GSK_CORNER_BOTTOM_LEFT].height,
+                                         weight);
+              gsk_path_builder_line_to (builder,
+                                        stroke_box.bounds.origin.x,
+                                        stroke_box.bounds.origin.y + stroke_box.corner[GSK_CORNER_TOP_LEFT].height);
+              gsk_path_builder_conic_to (builder,
+                                         stroke_box.bounds.origin.x,
+                                         stroke_box.bounds.origin.y,
+                                         stroke_box.bounds.origin.x + stroke_box.corner[GSK_CORNER_TOP_LEFT].width,
+                                         stroke_box.bounds.origin.y,
+                                         weight);
+            }
 
-          _gtk_rounded_box_path_side (&stroke_box, cr, i);
+          path = gsk_path_builder_free_to_path (builder);
+          stroke = create_stroke_style (border_width[i],
+                                        stroke_style,
+                                        _gtk_rounded_box_guess_length (&stroke_box, i));
+          gtk_snapshot_push_stroke (snapshot, path, stroke);
+          gsk_stroke_free (stroke);
+          gsk_path_unref (path);
 
-          gdk_cairo_set_source_rgba (cr, &colors[i]);
-          set_stroke_style (cr,
-                            border_width[i],
-                            stroke_style,
-                            _gtk_rounded_box_guess_length (&stroke_box, i));
-          cairo_stroke (cr);
+          gtk_snapshot_append_border (snapshot, border_box, border_width, colors);
 
-          cairo_restore (cr);
+          gtk_snapshot_pop (snapshot);
         }
     }
 }
 
-static void
-snapshot_frame_stroke (GtkSnapshot          *snapshot,
-                       const GskRoundedRect *outline,
-                       const float           border_width[4],
-                       GdkRGBA               colors[4],
-                       guint                 hidden_side,
-                       GtkBorderStyle        stroke_style)
-{
-  double double_width[4] = { border_width[0], border_width[1], border_width[2], border_width[3] };
-  cairo_t *cr;
-
-  cr = gtk_snapshot_append_cairo (snapshot,
-                                  &outline->bounds);
-  render_frame_stroke (cr, outline, double_width, colors, hidden_side, stroke_style);
-  cairo_destroy (cr);
-}
-
 static void
 color_shade (const GdkRGBA *color,
              double         factor,

gtk/gtksnapshot.c

@@ -34,6 +34,7 @@
 
 #include "gsk/gskrendernodeprivate.h"
 #include "gsk/gskroundedrectprivate.h"
+#include "gsk/gskstrokeprivate.h"
 
 #include "gtk/gskpango.h"
 
@@ -109,6 +110,14 @@ struct _GtkSnapshotState {
     struct {
       GskRoundedRect bounds;
     } rounded_clip;
+    struct {
+      GskPath *path;
+      GskFillRule fill_rule;
+    } fill;
+    struct {
+      GskPath *path;
+      GskStroke stroke;
+    } stroke;
     struct {
       gsize n_shadows;
       GskShadow *shadows;
@@ -761,7 +770,7 @@ gtk_snapshot_ensure_translate (GtkSnapshot *snapshot,
       gtk_snapshot_autopush_transform (snapshot);
       state = gtk_snapshot_get_current_state (snapshot);
     }
-  
+
   gsk_transform_to_translate (state->transform, dx, dy);
 }
 
@@ -850,7 +859,7 @@ gtk_snapshot_push_clip (GtkSnapshot           *snapshot,
 {
   GtkSnapshotState *state;
   float scale_x, scale_y, dx, dy;
- 
+
   gtk_snapshot_ensure_affine (snapshot, &scale_x, &scale_y, &dx, &dy);
 
   state = gtk_snapshot_push_state (snapshot,
@@ -1096,6 +1105,135 @@ gtk_snapshot_push_rounded_clip (GtkSnapshot          *snapshot,
   gsk_rounded_rect_scale_affine (&state->data.rounded_clip.bounds, bounds, scale_x, scale_y, dx, dy);
 }
 
+static GskRenderNode *
+gtk_snapshot_collect_fill (GtkSnapshot      *snapshot,
+                           GtkSnapshotState *state,
+                           GskRenderNode   **nodes,
+                           guint             n_nodes)
+{
+  GskRenderNode *node, *fill_node;
+
+  node = gtk_snapshot_collect_default (snapshot, state, nodes, n_nodes);
+  if (node == NULL)
+    return NULL;
+
+  fill_node = gsk_fill_node_new (node,
+                                 state->data.fill.path,
+                                 state->data.fill.fill_rule);
+
+  if (fill_node->bounds.size.width == 0 ||
+      fill_node->bounds.size.height == 0)
+    {
+      gsk_render_node_unref (node);
+      gsk_render_node_unref (fill_node);
+      return NULL;
+    }
+
+  gsk_render_node_unref (node);
+
+  return fill_node;
+}
+
+static void
+gtk_snapshot_clear_fill (GtkSnapshotState *state)
+{
+  gsk_path_unref (state->data.fill.path);
+}
+
+/**
+ * gtk_snapshot_push_fill:
+ * @snapshot: a `GtkSnapshot`
+ * @path: The path describing the area to fill
+ * @fill_rule: The fill rule to use
+ *
+ * Fills the area given by @path and @fill_rule with an image and discards everything
+ * outside of it.
+ *
+ * The image is recorded until the next call to [method@Gtk.Snapshot.pop].
+ */
+void
+gtk_snapshot_push_fill (GtkSnapshot *snapshot,
+                        GskPath     *path,
+                        GskFillRule  fill_rule)
+{
+  GtkSnapshotState *state;
+
+  /* FIXME: Is it worth calling ensure_affine() and transforming the path here? */
+  gtk_snapshot_ensure_identity (snapshot);
+
+  state = gtk_snapshot_push_state (snapshot,
+                                   gtk_snapshot_get_current_state (snapshot)->transform,
+                                   gtk_snapshot_collect_fill,
+                                   gtk_snapshot_clear_fill);
+
+  state->data.fill.path = gsk_path_ref (path);
+  state->data.fill.fill_rule = fill_rule;
+}
+
+static GskRenderNode *
+gtk_snapshot_collect_stroke (GtkSnapshot      *snapshot,
+                             GtkSnapshotState *state,
+                             GskRenderNode   **nodes,
+                             guint             n_nodes)
+{
+  GskRenderNode *node, *stroke_node;
+
+  node = gtk_snapshot_collect_default (snapshot, state, nodes, n_nodes);
+  if (node == NULL)
+    return NULL;
+
+  stroke_node = gsk_stroke_node_new (node,
+                                     state->data.stroke.path,
+                                     &state->data.stroke.stroke);
+
+  if (stroke_node->bounds.size.width == 0 ||
+      stroke_node->bounds.size.height == 0)
+    {
+      gsk_render_node_unref (node);
+      gsk_render_node_unref (stroke_node);
+      return NULL;
+    }
+
+  gsk_render_node_unref (node);
+
+  return stroke_node;
+}
+
+static void
+gtk_snapshot_clear_stroke (GtkSnapshotState *state)
+{
+  gsk_path_unref (state->data.stroke.path);
+  gsk_stroke_clear (&state->data.stroke.stroke);
+}
+
+/**
+ * gtk_snapshot_push_stroke:
+ * @snapshot: a `GtkSnapshot`
+ * @path: The path to stroke
+ * @stroke: The stroke attributes
+ *
+ * Strokes the given @path with the attributes given by @stroke and the
+ * image being recorded until the next call to [method@Gtk.Snapshot.pop].
+ */
+void
+gtk_snapshot_push_stroke (GtkSnapshot     *snapshot,
+                          GskPath         *path,
+                          const GskStroke *stroke)
+{
+  GtkSnapshotState *state;
+
+  /* FIXME: Is it worth calling ensure_affine() and transforming the path here? */
+  gtk_snapshot_ensure_identity (snapshot);
+
+  state = gtk_snapshot_push_state (snapshot,
+                                   gtk_snapshot_get_current_state (snapshot)->transform,
+                                   gtk_snapshot_collect_stroke,
+                                   gtk_snapshot_clear_stroke);
+
+  state->data.stroke.path = gsk_path_ref (path);
+  gsk_stroke_init_copy (&state->data.stroke.stroke, stroke);
+}
+
 static GskRenderNode *
 gtk_snapshot_collect_shadow (GtkSnapshot      *snapshot,
                              GtkSnapshotState *state,
@@ -2522,7 +2660,7 @@ gtk_snapshot_append_border (GtkSnapshot          *snapshot,
   gsk_rounded_rect_scale_affine (&real_outline, outline, scale_x, scale_y, dx, dy);
 
   node = gsk_border_node_new (&real_outline,
-                              (float[4]) { 
+                              (float[4]) {
                                 border_width[0] * scale_y,
                                 border_width[1] * scale_x,
                                 border_width[2] * scale_y,

gtk/gtksnapshot.h

@@ -89,6 +89,14 @@ GDK_AVAILABLE_IN_ALL
 void            gtk_snapshot_push_rounded_clip          (GtkSnapshot            *snapshot,
                                                          const GskRoundedRect   *bounds);
 GDK_AVAILABLE_IN_ALL
+void            gtk_snapshot_push_fill                  (GtkSnapshot            *snapshot,
+                                                         GskPath                *path,
+                                                         GskFillRule             fill_rule);
+GDK_AVAILABLE_IN_ALL
+void            gtk_snapshot_push_stroke                (GtkSnapshot            *snapshot,
+                                                         GskPath                *path,
+                                                         const GskStroke        *stroke);
+GDK_AVAILABLE_IN_ALL
 void            gtk_snapshot_push_shadow                (GtkSnapshot            *snapshot,
                                                          const GskShadow        *shadow,
                                                          gsize                   n_shadows);

gtk/inspector/recorder.c

@@ -164,6 +164,12 @@ create_list_model_for_render_node (GskRenderNode *node)
     case GSK_ROUNDED_CLIP_NODE:
       return create_render_node_list_model ((GskRenderNode *[1]) { gsk_rounded_clip_node_get_child (node) }, 1);
 
+    case GSK_FILL_NODE:
+      return create_render_node_list_model ((GskRenderNode *[1]) { gsk_fill_node_get_child (node) }, 1);
+
+    case GSK_STROKE_NODE:
+      return create_render_node_list_model ((GskRenderNode *[1]) { gsk_stroke_node_get_child (node) }, 1);
+
     case GSK_SHADOW_NODE:
       return create_render_node_list_model ((GskRenderNode *[1]) { gsk_shadow_node_get_child (node) }, 1);
 
@@ -285,6 +291,10 @@ node_type_name (GskRenderNodeType type)
       return "Clip";
     case GSK_ROUNDED_CLIP_NODE:
       return "Rounded Clip";
+    case GSK_FILL_NODE:
+      return "Fill";
+    case GSK_STROKE_NODE:
+      return "Stroke";
     case GSK_SHADOW_NODE:
       return "Shadow";
     case GSK_BLEND_NODE:
@@ -324,6 +334,8 @@ node_name (GskRenderNode *node)
     case GSK_REPEAT_NODE:
     case GSK_CLIP_NODE:
     case GSK_ROUNDED_CLIP_NODE:
+    case GSK_FILL_NODE:
+    case GSK_STROKE_NODE:
     case GSK_SHADOW_NODE:
     case GSK_BLEND_NODE:
     case GSK_CROSS_FADE_NODE:
@@ -605,6 +617,20 @@ add_float_row (GtkListStore  *store,
   g_free (text);
 }
 
+static const char *
+enum_to_nick (GType type,
+              int   value)
+{
+  GEnumClass *class;
+  GEnumValue *v;
+
+  class = g_type_class_ref (type);
+  v = g_enum_get_value (class, value);
+  g_type_class_unref (class);
+
+  return v->value_nick;
+}
+
 static void
 populate_render_node_properties (GtkListStore  *store,
                                  GskRenderNode *node)
@@ -867,9 +893,7 @@ populate_render_node_properties (GtkListStore  *store,
     case GSK_BLEND_NODE:
       {
         GskBlendMode mode = gsk_blend_node_get_blend_mode (node);
-        tmp = g_enum_to_string (GSK_TYPE_BLEND_MODE, mode);
-        add_text_row (store, "Blendmode", tmp);
-        g_free (tmp);
+        add_text_row (store, "Blendmode", enum_to_nick (GSK_TYPE_BLEND_MODE, mode));
       }
       break;
 
@@ -1102,6 +1126,39 @@ populate_render_node_properties (GtkListStore  *store,
       }
       break;
 
+    case GSK_FILL_NODE:
+      {
+        GskPath *path = gsk_fill_node_get_path (node);
+        GskFillRule fill_rule = gsk_fill_node_get_fill_rule (node);
+
+        tmp = gsk_path_to_string (path);
+        add_text_row (store, "Path", tmp);
+        g_free (tmp);
+
+        add_text_row (store, "Fill rule", enum_to_nick (GSK_TYPE_FILL_RULE, fill_rule));
+      }
+      break;
+
+    case GSK_STROKE_NODE:
+      {
+        GskPath *path = gsk_stroke_node_get_path (node);
+        const GskStroke *stroke = gsk_stroke_node_get_stroke (node);
+        GskLineCap line_cap = gsk_stroke_get_line_cap (stroke);
+        GskLineJoin line_join = gsk_stroke_get_line_join (stroke);
+
+        tmp = gsk_path_to_string (path);
+        add_text_row (store, "Path", tmp);
+        g_free (tmp);
+
+        tmp = g_strdup_printf ("%.2f", gsk_stroke_get_line_width (stroke));
+        add_text_row (store, "Line width", tmp);
+        g_free (tmp);
+
+        add_text_row (store, "Line cap", enum_to_nick (GSK_TYPE_LINE_CAP, line_cap));
+        add_text_row (store, "Line join", enum_to_nick (GSK_TYPE_LINE_JOIN, line_join));
+      }
+      break;
+
     case GSK_CONTAINER_NODE:
       tmp = g_strdup_printf ("%d", gsk_container_node_get_n_children (node));
       add_text_row (store, "Children", tmp);

meson.build

@@ -783,7 +783,10 @@ project_build_root = meson.current_build_dir()
 subdir('gtk/css')
 subdir('gdk')
 subdir('gsk')
+subdir('ottie')
 subdir('gtk')
+subdir('ottie/tools')
+subdir('ottie/editor')
 subdir('modules')
 if get_option('demos')
   subdir('demos')

ottie/editor/main.c

@@ -0,0 +1,28 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#include "config.h"
+
+#include <ottie-editor-application.h>
+
+int
+main (int argc, char *argv[])
+{
+  return g_application_run (G_APPLICATION (ottie_editor_application_new ()), argc, argv);
+}

ottie/editor/meson.build

@@ -0,0 +1,31 @@
+ottie_editor_sources = [
+  'main.c',
+  'ottie-editor-application.c',
+  'ottie-editor-window.c',
+]
+
+ottie_editor_resources = gnome.compile_resources('ottie_editor_resources',
+  'ottie-editor.gresource.xml',
+  source_dir: '.',
+)
+
+executable('ottie-editor',
+  sources: [ottie_editor_sources, ottie_editor_resources],
+  dependencies: [libgtk_css_dep, libgdk_dep, libgsk_dep, libgtk_static_dep, libottie_dep],
+  include_directories: confinc,
+  c_args: [
+    '-DGTK_COMPILATION',
+    '-DG_LOG_DOMAIN="OttieEditor"',
+  ] + common_cflags,
+  gui_app: true,
+  link_with: [libgtk_static, libgtk_css, libgdk, libgsk, libottie],
+  link_args: common_ldflags,
+  install: false,
+)
+
+# icons, don't install them until we decide to install ottie-editor
+#icontheme_dir = join_paths(gtk_datadir, 'icons/hicolor')
+
+#foreach size: ['scalable', 'symbolic']
+#  install_subdir('data/' + size, install_dir: icontheme_dir)
+#endforeach

ottie/editor/ottie-editor-application.c

@@ -0,0 +1,215 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#include "config.h"
+
+#include "ottie-editor-application.h"
+
+#include "ottie-editor-window.h"
+
+struct _OttieEditorApplication
+{
+  GtkApplication parent;
+};
+
+struct _OttieEditorApplicationClass
+{
+  GtkApplicationClass parent_class;
+};
+
+G_DEFINE_TYPE(OttieEditorApplication, ottie_editor_application, GTK_TYPE_APPLICATION);
+
+static void
+ottie_editor_application_init (OttieEditorApplication *app)
+{
+}
+
+static void
+activate_about (GSimpleAction *action,
+                GVariant      *parameter,
+                gpointer       user_data)
+{
+  GtkApplication *app = user_data;
+  char *version;
+  GString *s;
+  char *os_name;
+  char *os_version;
+  GtkWidget *dialog;
+
+  os_name = g_get_os_info (G_OS_INFO_KEY_NAME);
+  os_version = g_get_os_info (G_OS_INFO_KEY_VERSION_ID);
+  s = g_string_new ("");
+  if (os_name && os_version)
+    g_string_append_printf (s, "OS\t%s %s\n\n", os_name, os_version);
+
+  g_string_append (s, "System libraries\n");
+  g_string_append_printf (s, "\tGLib\t%d.%d.%d\n",
+                          glib_major_version,
+                          glib_minor_version,
+                          glib_micro_version);
+  g_string_append_printf (s, "\tPango\t%s\n",
+                          pango_version_string ());
+  g_string_append_printf (s, "\tGTK\t%d.%d.%d\n",
+                          gtk_get_major_version (),
+                          gtk_get_minor_version (),
+                          gtk_get_micro_version ());
+
+  version = g_strdup_printf ("%s\nRunning against GTK %d.%d.%d",
+                             PACKAGE_VERSION,
+                             gtk_get_major_version (),
+                             gtk_get_minor_version (),
+                             gtk_get_micro_version ());
+
+  dialog = g_object_new (GTK_TYPE_ABOUT_DIALOG,
+                         "transient-for", gtk_application_get_active_window (app),
+                         "program-name", "GTK Node Editor",
+                         "version", version,
+                         "copyright", "© 2019—2020 The GTK Team",
+                         "license-type", GTK_LICENSE_LGPL_2_1,
+                         "website", "http://www.gtk.org",
+                         "comments", "Program to test GTK rendering",
+                         "authors", (const char *[]){ "Benjamin Otte", "Timm Bäder", NULL},
+                         "logo-icon-name", "org.gtk.gtk4.OttieEditor.Devel",
+                         "title", "About GTK Node Editor",
+                         "system-information", s->str,
+                         NULL);
+  gtk_about_dialog_add_credit_section (GTK_ABOUT_DIALOG (dialog),
+                                       "Artwork by", (const char *[]) { "Jakub Steiner", NULL });
+
+  gtk_window_present (GTK_WINDOW (dialog));
+
+  g_string_free (s, TRUE);
+  g_free (version);
+  g_free (os_name);
+  g_free (os_version);
+}
+
+static void
+activate_quit (GSimpleAction *action,
+               GVariant      *parameter,
+               gpointer       data)
+{
+  g_application_quit (G_APPLICATION (data));
+}
+
+static void
+activate_inspector (GSimpleAction *action,
+                    GVariant      *parameter,
+                    gpointer       user_data)
+{
+  gtk_window_set_interactive_debugging (TRUE);
+}
+
+static void
+activate_help (GSimpleAction *action,
+               GVariant      *parameter,
+               gpointer       user_data)
+{
+  GtkBuilder *builder;
+  GtkWidget *window;
+  GtkTextBuffer *buffer;
+  GBytes *bytes;
+  const char *text;
+  gsize len;
+
+  builder = gtk_builder_new ();
+  gtk_builder_add_from_resource (builder, "/org/gtk/gtk4/node-editor/help-window.ui", NULL);
+  window = GTK_WIDGET (gtk_builder_get_object (builder, "window"));
+  buffer = GTK_TEXT_BUFFER (gtk_builder_get_object (builder, "buffer"));
+
+  bytes = g_resources_lookup_data ("/org/gtk/gtk4/node-editor/node-format.md",
+                                   G_RESOURCE_LOOKUP_FLAGS_NONE,
+                                   NULL);
+  text = g_bytes_get_data (bytes, &len);
+  gtk_text_buffer_set_text (buffer, text, len);
+  g_bytes_unref (bytes);
+
+  gtk_window_present (GTK_WINDOW (window));
+  g_object_unref (builder);
+}
+
+static GActionEntry app_entries[] =
+{
+  { "about", activate_about, NULL, NULL, NULL },
+  { "quit", activate_quit, NULL, NULL, NULL },
+  { "inspector", activate_inspector, NULL, NULL, NULL },
+  { "help", activate_help, NULL, NULL, NULL },
+};
+
+static void
+ottie_editor_application_startup (GApplication *app)
+{
+  const char *help_accels[2] = { "F1", NULL };
+  const char *quit_accels[2] = { "<Ctrl>Q", NULL };
+  const char *open_accels[2] = { "<Ctrl>O", NULL };
+
+  G_APPLICATION_CLASS (ottie_editor_application_parent_class)->startup (app);
+
+  g_action_map_add_action_entries (G_ACTION_MAP (app),
+                                   app_entries, G_N_ELEMENTS (app_entries),
+                                   app);
+  gtk_application_set_accels_for_action (GTK_APPLICATION (app), "app.help", help_accels);
+  gtk_application_set_accels_for_action (GTK_APPLICATION (app), "app.quit", quit_accels);
+  gtk_application_set_accels_for_action (GTK_APPLICATION (app), "win.open", open_accels);
+}
+
+static void
+ottie_editor_application_activate (GApplication *app)
+{
+  OttieEditorWindow *win;
+
+  win = ottie_editor_window_new (OTTIE_EDITOR_APPLICATION (app));
+  gtk_window_present (GTK_WINDOW (win));
+}
+
+static void
+ottie_editor_application_open (GApplication  *app,
+                              GFile        **files,
+                              int            n_files,
+                              const char    *hint)
+{
+  OttieEditorWindow *win;
+  int i;
+
+  for (i = 0; i < n_files; i++)
+    {
+      win = ottie_editor_window_new (OTTIE_EDITOR_APPLICATION (app));
+      ottie_editor_window_load (win, files[i]);
+      gtk_window_present (GTK_WINDOW (win));
+    }
+}
+
+static void
+ottie_editor_application_class_init (OttieEditorApplicationClass *class)
+{
+  GApplicationClass *application_class = G_APPLICATION_CLASS (class);
+
+  application_class->startup = ottie_editor_application_startup;
+  application_class->activate = ottie_editor_application_activate;
+  application_class->open = ottie_editor_application_open;
+}
+
+OttieEditorApplication *
+ottie_editor_application_new (void)
+{
+  return g_object_new (OTTIE_EDITOR_APPLICATION_TYPE,
+                       "application-id", "org.gtk.gtk4.OttieEditor",
+                       "flags", G_APPLICATION_HANDLES_OPEN,
+                       NULL);
+}

ottie/editor/ottie-editor-application.h

@@ -0,0 +1,38 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#ifndef __OTTIE_EDITOR_APPLICATION_H__
+#define __OTTIE_EDITOR_APPLICATION_H__
+
+#include <gtk/gtk.h>
+
+
+#define OTTIE_EDITOR_APPLICATION_TYPE (ottie_editor_application_get_type ())
+#define OTTIE_EDITOR_APPLICATION(obj) (G_TYPE_CHECK_INSTANCE_CAST ((obj), OTTIE_EDITOR_APPLICATION_TYPE, OttieEditorApplication))
+
+
+typedef struct _OttieEditorApplication       OttieEditorApplication;
+typedef struct _OttieEditorApplicationClass  OttieEditorApplicationClass;
+
+
+GType                   ottie_editor_application_get_type       (void);
+OttieEditorApplication *ottie_editor_application_new            (void);
+
+
+#endif /* __OTTIE_EDITOR_APPLICATION_H__ */

ottie/editor/ottie-editor-window.c

@@ -0,0 +1,431 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#include "config.h"
+
+#include "ottie-editor-window.h"
+
+#include "ottie/ottiecreationprivate.h"
+#include "ottie/ottiecompositionlayerprivate.h"
+#include "ottie/ottiegroupshapeprivate.h"
+#include "ottie/ottieshapelayerprivate.h"
+#include "ottie/ottiepaintable.h"
+
+struct _OttieEditorWindow
+{
+  GtkApplicationWindow parent;
+
+  GFileMonitor *file_monitor;
+
+  OttieCreation *creation;
+  OttiePaintable *paintable;
+
+  GtkWidget *picture;
+  GtkWidget *listview;
+};
+
+struct _OttieEditorWindowClass
+{
+  GtkApplicationWindowClass parent_class;
+};
+
+G_DEFINE_TYPE(OttieEditorWindow, ottie_editor_window, GTK_TYPE_APPLICATION_WINDOW);
+
+static gboolean
+load_file_contents (OttieEditorWindow *self,
+                    GFile             *file)
+{
+  GBytes *bytes;
+
+  bytes = g_file_load_bytes (file, NULL, NULL, NULL);
+  if (bytes == NULL)
+    return FALSE;
+
+  if (!g_utf8_validate (g_bytes_get_data (bytes, NULL), g_bytes_get_size (bytes), NULL))
+    {
+      g_bytes_unref (bytes);
+      return FALSE;
+    }
+
+  ottie_creation_load_bytes (self->creation, bytes);
+#if 0
+  gtk_text_buffer_set_text (self->text_buffer,
+                            g_bytes_get_data (bytes, NULL),
+                            g_bytes_get_size (bytes));
+#endif
+
+  g_bytes_unref (bytes);
+
+  return TRUE;
+}
+
+static void
+file_changed_cb (GFileMonitor      *monitor,
+                 GFile             *file,
+                 GFile             *other_file,
+                 GFileMonitorEvent  event_type,
+                 gpointer           user_data)
+{
+  OttieEditorWindow *self = user_data;
+
+  if (event_type == G_FILE_MONITOR_EVENT_CHANGED)
+    load_file_contents (self, file);
+}
+
+void
+ottie_editor_window_load (OttieEditorWindow *self,
+                          GFile            *file)
+{
+  GError *error = NULL;
+
+  if (!load_file_contents (self, file))
+    return;
+
+  g_clear_object (&self->file_monitor);
+  self->file_monitor = g_file_monitor_file (file, G_FILE_MONITOR_NONE, NULL, &error);
+
+  if (error)
+    {
+      g_warning ("couldn't monitor file: %s", error->message);
+      g_error_free (error);
+    }
+  else
+    {
+      g_signal_connect (self->file_monitor, "changed", G_CALLBACK (file_changed_cb), self);
+    }
+}
+
+static void
+open_response_cb (GtkWidget        *dialog,
+                  int               response,
+                  OttieEditorWindow *self)
+{
+  gtk_widget_hide (dialog);
+
+  if (response == GTK_RESPONSE_ACCEPT)
+    {
+      GFile *file;
+
+      file = gtk_file_chooser_get_file (GTK_FILE_CHOOSER (dialog));
+      ottie_editor_window_load (self, file);
+      g_object_unref (file);
+    }
+
+  gtk_window_destroy (GTK_WINDOW (dialog));
+}
+
+static void
+show_open_filechooser (OttieEditorWindow *self)
+{
+  GtkWidget *dialog;
+
+  dialog = gtk_file_chooser_dialog_new ("Open lottie file",
+                                        GTK_WINDOW (self),
+                                        GTK_FILE_CHOOSER_ACTION_OPEN,
+                                        "_Cancel", GTK_RESPONSE_CANCEL,
+                                        "_Load", GTK_RESPONSE_ACCEPT,
+                                        NULL);
+
+  gtk_dialog_set_default_response (GTK_DIALOG (dialog), GTK_RESPONSE_ACCEPT);
+  gtk_window_set_modal (GTK_WINDOW (dialog), TRUE);
+
+  GFile *cwd = g_file_new_for_path (".");
+  gtk_file_chooser_set_current_folder (GTK_FILE_CHOOSER (dialog), cwd, NULL);
+  g_object_unref (cwd);
+
+  g_signal_connect (dialog, "response", G_CALLBACK (open_response_cb), self);
+  gtk_widget_show (dialog);
+}
+
+static void
+open_cb (GtkWidget        *button,
+         OttieEditorWindow *self)
+{
+  show_open_filechooser (self);
+}
+
+static void
+save_response_cb (GtkWidget        *dialog,
+                  int               response,
+                  OttieEditorWindow *self)
+{
+  gtk_widget_hide (dialog);
+
+  if (response == GTK_RESPONSE_ACCEPT)
+    {
+#if 0
+      GFile *file;
+      char *text;
+#endif
+      GError *error = NULL;
+
+#if 0
+      text = get_current_text (self->text_buffer);
+
+      file = gtk_file_chooser_get_file (GTK_FILE_CHOOSER (dialog));
+      g_file_replace_contents (file, text, strlen (text),
+                               NULL, FALSE,
+                               G_FILE_CREATE_NONE,
+                               NULL,
+                               NULL,
+                               &error);
+#endif
+
+      if (error != NULL)
+        {
+          GtkWidget *message_dialog;
+
+          message_dialog = gtk_message_dialog_new (GTK_WINDOW (gtk_widget_get_root (GTK_WIDGET (self))),
+                                                   GTK_DIALOG_MODAL|GTK_DIALOG_DESTROY_WITH_PARENT,
+                                                   GTK_MESSAGE_INFO,
+                                                   GTK_BUTTONS_OK,
+                                                   "Saving failed");
+          gtk_message_dialog_format_secondary_text (GTK_MESSAGE_DIALOG (message_dialog),
+                                                    "%s", error->message);
+          g_signal_connect (message_dialog, "response", G_CALLBACK (gtk_window_destroy), NULL);
+          gtk_widget_show (message_dialog);
+          g_error_free (error);
+        }
+
+#if 0
+      g_free (text);
+      g_object_unref (file);
+#endif
+    }
+
+  gtk_window_destroy (GTK_WINDOW (dialog));
+}
+
+static void
+save_cb (GtkWidget        *button,
+         OttieEditorWindow *self)
+{
+  GtkWidget *dialog;
+
+  dialog = gtk_file_chooser_dialog_new ("Save file",
+                                        GTK_WINDOW (gtk_widget_get_root (GTK_WIDGET (button))),
+                                        GTK_FILE_CHOOSER_ACTION_SAVE,
+                                        "_Cancel", GTK_RESPONSE_CANCEL,
+                                        "_Save", GTK_RESPONSE_ACCEPT,
+                                        NULL);
+
+  gtk_dialog_set_default_response (GTK_DIALOG (dialog), GTK_RESPONSE_ACCEPT);
+  gtk_window_set_modal (GTK_WINDOW (dialog), TRUE);
+
+  GFile *cwd = g_file_new_for_path (".");
+  gtk_file_chooser_set_current_folder (GTK_FILE_CHOOSER (dialog), cwd, NULL);
+  g_object_unref (cwd);
+
+  g_signal_connect (dialog, "response", G_CALLBACK (save_response_cb), self);
+  gtk_widget_show (dialog);
+}
+
+static GdkTexture *
+create_texture (OttieEditorWindow *self)
+{
+  GtkSnapshot *snapshot;
+  GskRenderer *renderer;
+  GskRenderNode *node;
+  GdkTexture *texture;
+  int width, height;
+
+  width = gdk_paintable_get_intrinsic_width (GDK_PAINTABLE (self->paintable));
+  height = gdk_paintable_get_intrinsic_height (GDK_PAINTABLE (self->paintable));
+
+  if (width <= 0 || height <= 0)
+    return NULL;
+  snapshot = gtk_snapshot_new ();
+  gdk_paintable_snapshot (GDK_PAINTABLE (self->paintable), snapshot, width, height);
+  node = gtk_snapshot_free_to_node (snapshot);
+  if (node == NULL)
+    return NULL;
+
+  renderer = gtk_native_get_renderer (gtk_widget_get_native (GTK_WIDGET (self)));
+  texture = gsk_renderer_render_texture (renderer, node, NULL);
+  gsk_render_node_unref (node);
+
+  return texture;
+}
+
+static void
+export_image_response_cb (GtkWidget  *dialog,
+                          int         response,
+                          GdkTexture *texture)
+{
+  gtk_widget_hide (dialog);
+
+  if (response == GTK_RESPONSE_ACCEPT)
+    {
+      GFile *file;
+
+      file = gtk_file_chooser_get_file (GTK_FILE_CHOOSER (dialog));
+      if (!gdk_texture_save_to_png (texture, g_file_peek_path (file)))
+        {
+          GtkWidget *message_dialog;
+
+          message_dialog = gtk_message_dialog_new (GTK_WINDOW (gtk_window_get_transient_for (GTK_WINDOW (dialog))),
+                                                   GTK_DIALOG_MODAL|GTK_DIALOG_DESTROY_WITH_PARENT,
+                                                   GTK_MESSAGE_INFO,
+                                                   GTK_BUTTONS_OK,
+                                                   "Exporting to image failed");
+          g_signal_connect (message_dialog, "response", G_CALLBACK (gtk_window_destroy), NULL);
+          gtk_widget_show (message_dialog);
+        }
+
+      g_object_unref (file);
+    }
+
+  gtk_window_destroy (GTK_WINDOW (dialog));
+  g_object_unref (texture);
+}
+
+static void
+export_image_cb (GtkWidget        *button,
+                 OttieEditorWindow *self)
+{
+  GdkTexture *texture;
+  GtkWidget *dialog;
+
+  texture = create_texture (self);
+  if (texture == NULL)
+    return;
+
+  dialog = gtk_file_chooser_dialog_new ("",
+                                        GTK_WINDOW (gtk_widget_get_root (GTK_WIDGET (button))),
+                                        GTK_FILE_CHOOSER_ACTION_SAVE,
+                                        "_Cancel", GTK_RESPONSE_CANCEL,
+                                        "_Save", GTK_RESPONSE_ACCEPT,
+                                        NULL);
+
+  gtk_dialog_set_default_response (GTK_DIALOG (dialog), GTK_RESPONSE_ACCEPT);
+  gtk_window_set_modal (GTK_WINDOW (dialog), TRUE);
+  g_signal_connect (dialog, "response", G_CALLBACK (export_image_response_cb), texture);
+  gtk_widget_show (dialog);
+}
+
+static GListModel *
+create_object_children (gpointer item,
+                        gpointer user_data)
+{
+  if (OTTIE_IS_COMPOSITION_LAYER (item))
+    {
+      return G_LIST_MODEL (g_object_ref (ottie_composition_layer_get_composition (item)));
+    }
+  else if (OTTIE_IS_SHAPE_LAYER (item))
+    {
+      return G_LIST_MODEL (g_object_ref (ottie_shape_layer_get_shape (item)));
+    }
+  else if (OTTIE_IS_GROUP_SHAPE (item))
+    {
+      return g_object_ref (item);
+    }
+  else
+    {
+      return NULL;
+    }
+}
+
+static void
+notify_prepared_cb (OttieCreation     *creation,
+                    GParamSpec        *pspec,
+                    OttieEditorWindow *self)
+{
+  GtkTreeListModel *treemodel;
+  GtkSingleSelection *selection;
+
+  if (ottie_creation_is_prepared (creation))
+    {
+      treemodel = gtk_tree_list_model_new (G_LIST_MODEL (ottie_creation_get_composition (self->creation)),
+                                           FALSE,
+                                           TRUE,
+                                           create_object_children,
+                                           NULL,
+                                           NULL);
+     selection = gtk_single_selection_new (G_LIST_MODEL (treemodel));
+     gtk_list_view_set_model (GTK_LIST_VIEW (self->listview), GTK_SELECTION_MODEL (selection));
+     g_object_unref (selection);
+    }
+  else
+    {
+     gtk_list_view_set_model (GTK_LIST_VIEW (self->listview), NULL);
+    }
+}
+
+static void
+ottie_editor_window_finalize (GObject *object)
+{
+  //OttieEditorWindow *self = OTTIE_EDITOR_WINDOW (object);
+
+  G_OBJECT_CLASS (ottie_editor_window_parent_class)->finalize (object);
+}
+
+static void
+ottie_editor_window_class_init (OttieEditorWindowClass *class)
+{
+  GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (class);
+  GObjectClass *object_class = G_OBJECT_CLASS (class);
+
+  object_class->finalize = ottie_editor_window_finalize;
+
+  g_type_ensure (OTTIE_TYPE_CREATION);
+  g_type_ensure (OTTIE_TYPE_PAINTABLE);
+
+  gtk_widget_class_set_template_from_resource (widget_class,
+                                               "/org/gtk/gtk4/ottie-editor/ottie-editor-window.ui");
+
+  gtk_widget_class_bind_template_child (widget_class, OttieEditorWindow, creation);
+  gtk_widget_class_bind_template_child (widget_class, OttieEditorWindow, paintable);
+  gtk_widget_class_bind_template_child (widget_class, OttieEditorWindow, picture);
+  gtk_widget_class_bind_template_child (widget_class, OttieEditorWindow, listview);
+
+  gtk_widget_class_bind_template_callback (widget_class, open_cb);
+  gtk_widget_class_bind_template_callback (widget_class, save_cb);
+  gtk_widget_class_bind_template_callback (widget_class, export_image_cb);
+  gtk_widget_class_bind_template_callback (widget_class, notify_prepared_cb);
+}
+
+static void
+window_open (GSimpleAction *action,
+             GVariant      *parameter,
+             gpointer       user_data)
+{
+  OttieEditorWindow *self = user_data;
+
+  show_open_filechooser (self);
+}
+
+static GActionEntry win_entries[] = {
+  { "open", window_open, NULL, NULL, NULL },
+};
+
+static void
+ottie_editor_window_init (OttieEditorWindow *self)
+{
+  gtk_widget_init_template (GTK_WIDGET (self));
+
+  g_action_map_add_action_entries (G_ACTION_MAP (self), win_entries, G_N_ELEMENTS (win_entries), self);
+}
+
+OttieEditorWindow *
+ottie_editor_window_new (OttieEditorApplication *application)
+{
+  return g_object_new (OTTIE_EDITOR_WINDOW_TYPE,
+                       "application", application,
+                       NULL);
+}

ottie/editor/ottie-editor-window.h

@@ -0,0 +1,42 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#ifndef __OTTIE_EDITOR_WINDOW_H__
+#define __OTTIE_EDITOR_WINDOW_H__
+
+#include <gtk/gtk.h>
+
+#include "ottie-editor-application.h"
+
+#define OTTIE_EDITOR_WINDOW_TYPE (ottie_editor_window_get_type ())
+#define OTTIE_EDITOR_WINDOW(obj) (G_TYPE_CHECK_INSTANCE_CAST ((obj), OTTIE_EDITOR_WINDOW_TYPE, OttieEditorWindow))
+
+
+typedef struct _OttieEditorWindow         OttieEditorWindow;
+typedef struct _OttieEditorWindowClass    OttieEditorWindowClass;
+
+
+GType                   ottie_editor_window_get_type            (void);
+
+OttieEditorWindow *     ottie_editor_window_new                 (OttieEditorApplication *application);
+
+void                    ottie_editor_window_load                (OttieEditorWindow      *self,
+                                                                 GFile                  *file);
+
+#endif /* __OTTIE_EDITOR_WINDOW_H__ */

ottie/editor/ottie-editor-window.ui

@@ -0,0 +1,133 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<interface>
+  <menu id="gear_menu">
+    <section>
+      <item>
+        <attribute name="label" translatable="yes">_Help</attribute>
+        <attribute name="action">app.help</attribute>
+      </item>
+      <item>
+        <attribute name="label" translatable="yes">_Inspector</attribute>
+        <attribute name="action">app.inspector</attribute>
+      </item>
+      <item>
+        <attribute name="label" translatable="yes">_About Ottie Editor</attribute>
+        <attribute name="action">app.about</attribute>
+      </item>
+    </section>
+  </menu>
+
+  <object class="OttieCreation" id="creation">
+    <signal name="notify::prepared" handler="notify_prepared_cb"/>
+  </object>
+
+  <object class="OttiePaintable" id="paintable">
+    <property name="creation">creation</property>
+  </object>
+
+  <template class="OttieEditorWindow" parent="GtkApplicationWindow">
+    <property name="title" translatable="yes">Ottie Editor</property>
+    <property name="default-width">1024</property>
+    <property name="default-height">768</property>
+    <child type="titlebar">
+      <object class="GtkHeaderBar" id="header">
+        <child type="start">
+          <object class="GtkButton">
+            <property name="icon-name">document-open-symbolic</property>
+            <property name="tooltip-text">Open file</property>
+            <signal name="clicked" handler="open_cb"/>
+          </object>
+        </child>
+        <child type="start">
+          <object class="GtkButton">
+            <property name="icon-name">document-save-symbolic</property>
+            <property name="tooltip-text">Save</property>
+            <signal name="clicked" handler="save_cb"/>
+          </object>
+        </child>
+        <child type="start">
+          <object class="GtkButton">
+            <property name="icon-name">insert-image-symbolic</property>
+            <property name="tooltip-text">Export to image</property>
+            <signal name="clicked" handler="export_image_cb"/>
+          </object>
+        </child>
+        <child type="end">
+          <object class="GtkMenuButton" id="gear_menu_button">
+            <property name="valign">center</property>
+            <property name="menu-model">gear_menu</property>
+            <property name="icon-name">open-menu-symbolic</property>
+          </object>
+        </child>
+      </object>
+    </child>
+    <child>
+      <object class="GtkPaned">
+        <property name="shrink-end-child">false</property>
+        <property name="position">400</property>
+        <child>
+          <object class="GtkScrolledWindow">
+            <property name="hexpand">1</property>
+            <property name="vexpand">1</property>
+            <child>
+              <object class="GtkListView" id="listview">
+                <property name="factory">
+                  <object class="GtkBuilderListItemFactory">
+                    <property name="bytes"><![CDATA[
+<?xml version="1.0" encoding="UTF-8"?>
+<interface>
+  <template class="GtkListItem">
+    <property name="child">
+      <object class="GtkTreeExpander" id="expander">
+        <binding name="list-row">
+          <lookup name="item">GtkListItem</lookup>
+        </binding>
+        <property name="child">
+          <object class="GtkLabel">
+            <property name="xalign">0</property>
+            <binding name="label">
+              <lookup name="name" type="OttieObject">
+                <lookup name="item">expander</lookup>
+              </lookup>
+            </binding>
+          </object>
+        </property>
+      </object>
+    </property>
+  </template>
+</interface>
+                    ]]></property>
+                  </object>
+                </property>
+              </object>
+            </child>
+          </object>
+        </child>
+        <child>
+          <object class="GtkBox">
+            <child>
+              <object class="GtkScrolledWindow">
+                <property name="hexpand">1</property>
+                <property name="vexpand">1</property>
+                <property name="min-content-height">100</property>
+                <property name="min-content-width">100</property>
+                <child>
+                  <object class="GtkViewport">
+                    <child>
+                      <object class="GtkPicture" id="picture">
+                        <property name="can-shrink">0</property>
+                        <property name="paintable">paintable</property>
+                        <property name="halign">center</property>
+                        <property name="valign">center</property>
+                      </object>
+                    </child>
+                  </object>
+                </child>
+              </object>
+            </child>
+          </object>
+        </child>
+      </object>
+    </child>
+  </template>
+</interface>

ottie/editor/ottie-editor.gresource.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<gresources>
+  <gresource prefix="/org/gtk/gtk4/ottie-editor">
+    <file preprocess="xml-stripblanks">ottie-editor-window.ui</file>
+  </gresource>
+</gresources>

ottie/meson.build

@@ -0,0 +1,71 @@
+ottie_public_sources = files([
+  'ottiecreation.c',
+  'ottiepaintable.c',
+  'ottieplayer.c',
+])
+
+ottie_private_sources = files([
+  'ottiecolorvalue.c',
+  'ottiecomposition.c',
+  'ottiecompositionlayer.c',
+  'ottiedoublevalue.c',
+  'ottieellipseshape.c',
+  'ottiefillshape.c',
+  'ottiegroupshape.c',
+  'ottielayer.c',
+  'ottienulllayer.c',
+  'ottieobject.c',
+  'ottieparser.c',
+  'ottiepathshape.c',
+  'ottiepathvalue.c',
+  'ottiepointvalue.c',
+  'ottiepoint3dvalue.c',
+  'ottierectshape.c',
+  'ottierender.c',
+  'ottieshape.c',
+  'ottieshapelayer.c',
+  'ottiestrokeshape.c',
+  'ottietransform.c',
+  'ottietrimshape.c',
+])
+
+ottie_public_headers = files([
+  'ottie.h',
+  'ottiecreation.h',
+  'ottiepaintable.h',
+  'ottieplayer.h',
+])
+
+install_headers(ottie_public_headers, 'ottie.h', subdir: 'gtk-4.0/ottie')
+
+json_glib_dep = dependency('json-glib-1.0', required: true)
+ottie_deps = [
+  libm,
+  glib_dep,
+  gobject_dep,
+  platform_gio_dep,
+  libgdk_dep,
+  libgsk_dep,
+  json_glib_dep
+]
+
+libottie = static_library('ottie',
+                            sources: [
+                              ottie_public_sources,
+                              ottie_private_sources,
+                            ],
+                            dependencies: ottie_deps,
+                            include_directories: [ confinc, ],
+                            c_args: [
+                              '-DGTK_COMPILATION',
+                              '-DG_LOG_DOMAIN="Ottie"',
+                            ] + common_cflags,
+                            link_with: [libgdk, libgsk ],
+                            link_args: common_ldflags)
+
+# We don't have link_with: to internal static libs here on purpose, just
+# list the dependencies and generated headers and such, for use in the
+# "public" libgtk_dep used by internal executables.
+libottie_dep = declare_dependency(include_directories: [ confinc, ],
+                                  dependencies: ottie_deps)
+

ottie/ottie.h

@@ -0,0 +1,31 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#ifndef __OTTIE_H__
+#define __OTTIE_H__
+
+#define __OTTIE_H_INSIDE__
+
+#include <ottie/ottiecreation.h>
+#include <ottie/ottiepaintable.h>
+#include <ottie/ottieplayer.h>
+
+#undef __OTTIE_H_INSIDE__
+
+#endif /* __OTTIE_H__ */

ottie/ottiecolorvalue.c

@@ -0,0 +1,149 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#include "config.h"
+
+#include "ottiecolorvalueprivate.h"
+
+#include "ottieparserprivate.h"
+
+#include <glib/gi18n-lib.h>
+
+static gboolean
+ottie_color_value_parse_one (JsonReader *reader,
+                             gsize       offset,
+                             gpointer    data)
+{
+  GdkRGBA *rgba = (GdkRGBA *) ((guint8 *) data + offset);
+  double d[3];
+
+  if (!ottie_parser_parse_array (reader, "color value",
+                                 3, 3, NULL,
+                                 0, sizeof (double),
+                                 ottie_parser_option_double,
+                                 d))
+    {
+      d[0] = d[1] = d[2] = 0;
+    }
+
+  rgba->red = d[0];
+  rgba->green = d[1];
+  rgba->blue = d[2];
+  rgba->alpha = 1;
+
+  return TRUE;
+}
+
+static void
+ottie_color_value_interpolate (const GdkRGBA *start,
+                               const GdkRGBA *end,
+                               double         progress,
+                               GdkRGBA       *result)
+{
+  result->red = start->red + progress * (end->red - start->red);
+  result->green = start->green + progress * (end->green - start->green);
+  result->blue = start->blue + progress * (end->blue - start->blue);
+  result->alpha = start->alpha + progress * (end->alpha - start->alpha);
+}
+
+#define OTTIE_KEYFRAMES_NAME ottie_color_keyframes
+#define OTTIE_KEYFRAMES_TYPE_NAME OttieColorKeyframes
+#define OTTIE_KEYFRAMES_ELEMENT_TYPE GdkRGBA
+#define OTTIE_KEYFRAMES_BY_VALUE 1
+#define OTTIE_KEYFRAMES_DIMENSIONS 4
+#define OTTIE_KEYFRAMES_PARSE_FUNC ottie_color_value_parse_one
+#define OTTIE_KEYFRAMES_INTERPOLATE_FUNC ottie_color_value_interpolate
+#include "ottiekeyframesimpl.c"
+
+void
+ottie_color_value_init (OttieColorValue *self,
+                        const GdkRGBA   *value)
+{
+  self->is_static = TRUE;
+  self->static_value = *value;
+}
+
+void
+ottie_color_value_clear (OttieColorValue *self)
+{
+  if (!self->is_static)
+    g_clear_pointer (&self->keyframes, ottie_color_keyframes_free);
+}
+
+void
+ottie_color_value_get (OttieColorValue *self,
+                       double           timestamp,
+                       GdkRGBA         *rgba)
+{
+  if (self->is_static)
+    {
+      *rgba = self->static_value;
+      return;
+    }
+  
+  ottie_color_keyframes_get (self->keyframes, timestamp, rgba);
+}
+
+gboolean
+ottie_color_value_parse (JsonReader *reader,
+                         gsize       offset,
+                         gpointer    data)
+{
+  OttieColorValue *self = (OttieColorValue *) ((guint8 *) data + offset);
+
+  if (json_reader_read_member (reader, "k"))
+    {
+      gboolean is_static;
+
+      if (!json_reader_is_array (reader))
+        is_static = TRUE;
+      else
+        {
+          if (json_reader_read_element (reader, 0))
+            is_static = !json_reader_is_object (reader);
+          else
+            is_static = TRUE;
+          json_reader_end_element (reader);
+        }
+
+      if (is_static)
+        {
+          self->is_static = TRUE;
+          ottie_color_value_parse_one (reader, 0, &self->static_value);
+        }
+      else
+        {
+          self->is_static = FALSE;
+          self->keyframes = ottie_color_keyframes_parse (reader);
+          if (self->keyframes == NULL)
+            {
+              json_reader_end_member (reader);
+              return FALSE;
+            }
+        }
+    }
+  else
+    {
+      ottie_parser_error_syntax (reader, "Property is not a color value");
+    }
+  json_reader_end_member (reader);
+
+  return TRUE;
+}
+

ottie/ottiecolorvalueprivate.h

@@ -0,0 +1,54 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#ifndef __OTTIE_COLOR_VALUE_PRIVATE_H__
+#define __OTTIE_COLOR_VALUE_PRIVATE_H__
+
+#include <json-glib/json-glib.h>
+
+#include <gdk/gdk.h>
+
+G_BEGIN_DECLS
+
+typedef struct _OttieColorValue OttieColorValue;
+
+struct _OttieColorValue
+{
+  gboolean is_static;
+  union {
+    GdkRGBA static_value;
+    gpointer keyframes;
+  };
+};
+
+void                      ottie_color_value_init                (OttieColorValue        *self,
+                                                                 const GdkRGBA          *rgba);
+void                      ottie_color_value_clear               (OttieColorValue        *self);
+
+void                      ottie_color_value_get                 (OttieColorValue        *self,
+                                                                 double                  timestamp,
+                                                                 GdkRGBA                *rgba);
+
+gboolean                  ottie_color_value_parse               (JsonReader             *reader,
+                                                                 gsize                   offset,
+                                                                 gpointer                data);
+
+G_END_DECLS
+
+#endif /* __OTTIE_COLOR_VALUE_PRIVATE_H__ */

ottie/ottiecomposition.c

@@ -0,0 +1,268 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#include "config.h"
+
+#include "ottiecompositionprivate.h"
+
+#include "ottieparserprivate.h"
+#include "ottiecompositionlayerprivate.h"
+#include "ottienulllayerprivate.h"
+#include "ottieshapelayerprivate.h"
+
+#include <glib/gi18n-lib.h>
+#include <gsk/gsk.h>
+
+#define GDK_ARRAY_ELEMENT_TYPE OttieLayer *
+#define GDK_ARRAY_FREE_FUNC g_object_unref
+#define GDK_ARRAY_TYPE_NAME OttieLayerList
+#define GDK_ARRAY_NAME ottie_layer_list
+#define GDK_ARRAY_PREALLOC 4
+#include "gdk/gdkarrayimpl.c"
+
+struct _OttieComposition
+{
+  OttieLayer parent;
+
+  OttieLayerList layers;
+  GHashTable *layers_by_index;
+};
+
+struct _OttieCompositionClass
+{
+  OttieLayerClass parent_class;
+};
+
+static GType
+ottie_composition_get_item_type (GListModel *list)
+{
+  return OTTIE_TYPE_LAYER;
+}
+
+static guint
+ottie_composition_get_n_items (GListModel *list)
+{
+  OttieComposition *self = OTTIE_COMPOSITION (list);
+
+  return ottie_layer_list_get_size (&self->layers);
+}
+
+static gpointer
+ottie_composition_get_item (GListModel *list,
+                             guint       position)
+{
+  OttieComposition *self = OTTIE_COMPOSITION (list);
+
+  if (position >= ottie_layer_list_get_size (&self->layers))
+    return NULL;
+
+  return g_object_ref (ottie_layer_list_get (&self->layers, position));
+}
+
+static void
+ottie_composition_list_model_init (GListModelInterface *iface)
+{
+  iface->get_item_type = ottie_composition_get_item_type;
+  iface->get_n_items = ottie_composition_get_n_items;
+  iface->get_item = ottie_composition_get_item;
+}
+
+G_DEFINE_TYPE_WITH_CODE (OttieComposition, ottie_composition, OTTIE_TYPE_LAYER,
+                         G_IMPLEMENT_INTERFACE (G_TYPE_LIST_MODEL, ottie_composition_list_model_init))
+
+static void
+ottie_composition_update (OttieLayer *layer,
+                          GHashTable *compositions)
+{
+  OttieComposition *self = OTTIE_COMPOSITION (layer);
+
+  for (gsize i = ottie_layer_list_get_size (&self->layers); i-- > 0; )
+    {
+      ottie_layer_update (ottie_layer_list_get (&self->layers, i), compositions);
+    }
+}
+
+static void
+ottie_composition_render (OttieLayer  *layer,
+                          OttieRender *render,
+                          double       timestamp)
+{
+  OttieComposition *self = OTTIE_COMPOSITION (layer);
+  OttieRender child_render;
+
+  ottie_render_init (&child_render);
+
+  for (gsize i = 0; i < ottie_layer_list_get_size (&self->layers); i++)
+    {
+      OttieLayer *child = ottie_layer_list_get (&self->layers, i);
+
+      ottie_layer_render (child, &child_render, timestamp);
+      /* XXX: Should we clear paths here because they're not needed anymore? */
+
+      /* Use a counter here to avoid inflooping */
+      for (gsize j = 0; j < ottie_layer_list_get_size (&self->layers); j++)
+        {
+          if (child->transform)
+            ottie_shape_render (OTTIE_SHAPE (child->transform), &child_render, timestamp);
+          if (child->parent_index == OTTIE_INT_UNSET)
+            break;
+          child = g_hash_table_lookup (self->layers_by_index, GINT_TO_POINTER (child->parent_index));
+          if (child == NULL)
+            break;
+        }
+
+      ottie_render_merge (render, &child_render);
+    }
+
+  ottie_render_clear (&child_render);
+}
+
+static void
+ottie_composition_dispose (GObject *object)
+{
+  OttieComposition *self = OTTIE_COMPOSITION (object);
+
+  ottie_layer_list_clear (&self->layers);
+  g_hash_table_remove_all (self->layers_by_index);
+
+  G_OBJECT_CLASS (ottie_composition_parent_class)->dispose (object);
+}
+
+static void
+ottie_composition_finalize (GObject *object)
+{
+  OttieComposition *self = OTTIE_COMPOSITION (object);
+
+  g_hash_table_unref (self->layers_by_index);
+
+  G_OBJECT_CLASS (ottie_composition_parent_class)->finalize (object);
+}
+
+static void
+ottie_composition_class_init (OttieCompositionClass *klass)
+{
+  OttieLayerClass *layer_class = OTTIE_LAYER_CLASS (klass);
+  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
+
+  layer_class->update = ottie_composition_update;
+  layer_class->render = ottie_composition_render;
+
+  gobject_class->dispose = ottie_composition_dispose;
+  gobject_class->finalize = ottie_composition_finalize;
+}
+
+static void
+ottie_composition_init (OttieComposition *self)
+{
+  ottie_layer_list_init (&self->layers);
+
+  self->layers_by_index = g_hash_table_new (g_direct_hash, g_direct_equal);
+}
+
+static void
+ottie_composition_append (OttieComposition *self,
+                          OttieLayer       *layer)
+{
+  ottie_layer_list_append (&self->layers, layer);
+  if (layer->index != OTTIE_INT_UNSET)
+    g_hash_table_insert (self->layers_by_index, GINT_TO_POINTER (layer->index), layer);
+  g_list_model_items_changed (G_LIST_MODEL (self), ottie_layer_list_get_size (&self->layers), 0, 1);
+}
+
+static gboolean
+ottie_composition_parse_layer (JsonReader *reader,
+                               gsize       offset,
+                               gpointer    data)
+{
+  OttieComposition *self = data;
+  OttieLayer *layer;
+  int type;
+
+  if (!json_reader_is_object (reader))
+    {
+      ottie_parser_error_syntax (reader, "Layer %zu is not an object",
+                                 ottie_layer_list_get_size (&self->layers));
+      return FALSE;
+    }
+
+  if (!json_reader_read_member (reader, "ty"))
+    {
+      ottie_parser_error_syntax (reader, "Layer %zu has no type",
+                                 ottie_layer_list_get_size (&self->layers));
+      json_reader_end_member (reader);
+      return FALSE;
+    }
+
+  type = json_reader_get_int_value (reader);
+  json_reader_end_member (reader);
+
+  switch (type)
+  {
+    case 0:
+      layer = ottie_composition_layer_parse (reader);
+      break;
+
+    case 3:
+      layer = ottie_null_layer_parse (reader);
+      break;
+
+    case 4:
+      layer = ottie_shape_layer_parse (reader);
+      break;
+
+    default:
+      ottie_parser_error_value (reader, "Layer %zu has unknown type %d",
+                                ottie_layer_list_get_size (&self->layers),
+                                type);
+      layer = NULL;
+      break;
+  }
+
+  if (layer)
+    ottie_composition_append (self, layer);
+
+  return TRUE;
+}
+
+gboolean
+ottie_composition_parse_layers (JsonReader *reader,
+                                gsize       offset,
+                                gpointer    data)
+{
+  OttieComposition **target = (OttieComposition **) ((guint8 *) data + offset);
+  OttieComposition *self;
+
+  self = g_object_new (OTTIE_TYPE_COMPOSITION, NULL);
+
+  if (!ottie_parser_parse_array (reader, "layers",
+                                 0, G_MAXUINT, NULL,
+                                 0, 0,
+                                 ottie_composition_parse_layer,
+                                 self))
+    {
+      g_object_unref (self);
+      return FALSE;
+    }
+
+  g_clear_object (target);
+  *target = self;
+
+  return TRUE;
+}
+

ottie/ottiecompositionlayer.c

@@ -0,0 +1,153 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#include "config.h"
+
+#include "ottiecompositionlayerprivate.h"
+
+#include "ottiedoublevalueprivate.h"
+
+#include <glib/gi18n-lib.h>
+#include <gsk/gsk.h>
+
+struct _OttieCompositionLayer
+{
+  OttieLayer parent;
+
+  OttieDoubleValue time_map;
+  double width;
+  double height;
+  char *ref_id;
+  OttieComposition *composition;
+};
+
+struct _OttieCompositionLayerClass
+{
+  OttieLayerClass parent_class;
+};
+
+G_DEFINE_TYPE (OttieCompositionLayer, ottie_composition_layer, OTTIE_TYPE_LAYER)
+
+static void
+ottie_composition_layer_update (OttieLayer *layer,
+                                GHashTable *compositions)
+{
+  OttieCompositionLayer *self = OTTIE_COMPOSITION_LAYER (layer);
+
+  g_clear_object (&self->composition);
+
+  if (self->ref_id)
+    self->composition = g_object_ref (g_hash_table_lookup (compositions, self->ref_id));
+}
+
+static void
+ottie_composition_layer_render (OttieLayer  *layer,
+                                OttieRender *render,
+                                double       timestamp)
+{
+  OttieCompositionLayer *self = OTTIE_COMPOSITION_LAYER (layer);
+  GskRenderNode *node;
+  double time_map;
+
+  if (self->composition == NULL)
+    return;
+
+  if (ottie_double_value_is_static (&self->time_map))
+    time_map = timestamp;
+  else
+    time_map = ottie_double_value_get (&self->time_map, timestamp);
+
+  ottie_layer_render (OTTIE_LAYER (self->composition),
+                      render,
+                      time_map);
+
+  node = ottie_render_get_node (render);
+  ottie_render_clear_nodes (render);
+  if (node)
+    {
+      ottie_render_add_node (render,
+                             gsk_clip_node_new (node,
+                                                &GRAPHENE_RECT_INIT (
+                                                  0, 0,
+                                                  self->width, self->height
+                                                )));
+      gsk_render_node_unref (node);
+    }
+}
+
+static void
+ottie_composition_layer_dispose (GObject *object)
+{
+  OttieCompositionLayer *self = OTTIE_COMPOSITION_LAYER (object);
+
+  g_clear_object (&self->composition);
+  g_clear_pointer (&self->ref_id, g_free);
+  ottie_double_value_clear (&self->time_map);
+
+  G_OBJECT_CLASS (ottie_composition_layer_parent_class)->dispose (object);
+}
+
+static void
+ottie_composition_layer_class_init (OttieCompositionLayerClass *klass)
+{
+  OttieLayerClass *layer_class = OTTIE_LAYER_CLASS (klass);
+  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
+
+  layer_class->update = ottie_composition_layer_update;
+  layer_class->render = ottie_composition_layer_render;
+
+  gobject_class->dispose = ottie_composition_layer_dispose;
+}
+
+static void
+ottie_composition_layer_init (OttieCompositionLayer *self)
+{
+  ottie_double_value_init (&self->time_map, 0);
+}
+
+OttieLayer *
+ottie_composition_layer_parse (JsonReader *reader)
+{
+  OttieParserOption options[] = {
+    OTTIE_PARSE_OPTIONS_LAYER,
+    { "refId", ottie_parser_option_string, G_STRUCT_OFFSET (OttieCompositionLayer, ref_id) },
+    { "tm", ottie_double_value_parse, 0 },
+    { "w", ottie_parser_option_double, G_STRUCT_OFFSET (OttieCompositionLayer, width)  },
+    { "h", ottie_parser_option_double, G_STRUCT_OFFSET (OttieCompositionLayer, height)  },
+  };
+  OttieCompositionLayer *self;
+
+  self = g_object_new (OTTIE_TYPE_COMPOSITION_LAYER, NULL);
+
+  if (!ottie_parser_parse_object (reader, "composition layer", options, G_N_ELEMENTS (options), self))
+    {
+      g_object_unref (self);
+      return NULL;
+    }
+
+  return OTTIE_LAYER (self);
+}
+
+OttieComposition *
+ottie_composition_layer_get_composition (OttieCompositionLayer *self)
+{
+  g_return_val_if_fail (OTTIE_IS_COMPOSITION_LAYER (self), NULL);
+
+  return self->composition;
+}

ottie/ottiecompositionlayerprivate.h

@@ -0,0 +1,49 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#ifndef __OTTIE_COMPOSITION_LAYER_PRIVATE_H__
+#define __OTTIE_COMPOSITION_LAYER_PRIVATE_H__
+
+#include "ottielayerprivate.h"
+
+#include "ottiecompositionprivate.h"
+
+#include <json-glib/json-glib.h>
+
+G_BEGIN_DECLS
+
+#define OTTIE_TYPE_COMPOSITION_LAYER         (ottie_composition_layer_get_type ())
+#define OTTIE_COMPOSITION_LAYER(o)           (G_TYPE_CHECK_INSTANCE_CAST ((o), OTTIE_TYPE_COMPOSITION_LAYER, OttieCompositionLayer))
+#define OTTIE_COMPOSITION_LAYER_CLASS(k)     (G_TYPE_CHECK_CLASS_CAST ((k), OTTIE_TYPE_COMPOSITION_LAYER, OttieCompositionLayerClass))
+#define OTTIE_IS_COMPOSITION_LAYER(o)        (G_TYPE_CHECK_INSTANCE_TYPE ((o), OTTIE_TYPE_COMPOSITION_LAYER))
+#define OTTIE_IS_COMPOSITION_LAYER_CLASS(k)  (G_TYPE_CHECK_CLASS_TYPE ((k), OTTIE_TYPE_COMPOSITION_LAYER))
+#define OTTIE_COMPOSITION_LAYER_GET_CLASS(o) (G_TYPE_INSTANCE_GET_CLASS ((o), OTTIE_TYPE_COMPOSITION_LAYER, OttieCompositionLayerClass))
+
+typedef struct _OttieCompositionLayer OttieCompositionLayer;
+typedef struct _OttieCompositionLayerClass OttieCompositionLayerClass;
+
+GType                   ottie_composition_layer_get_type        (void) G_GNUC_CONST;
+
+OttieComposition *      ottie_composition_layer_get_composition (OttieCompositionLayer  *self);
+
+OttieLayer *            ottie_composition_layer_parse           (JsonReader             *reader);
+
+G_END_DECLS
+
+#endif /* __OTTIE_COMPOSITION_LAYER_PRIVATE_H__ */

ottie/ottiecompositionprivate.h

@@ -0,0 +1,47 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#ifndef __OTTIE_COMPOSITION_PRIVATE_H__
+#define __OTTIE_COMPOSITION_PRIVATE_H__
+
+#include "ottielayerprivate.h"
+
+#include <json-glib/json-glib.h>
+
+G_BEGIN_DECLS
+
+#define OTTIE_TYPE_COMPOSITION         (ottie_composition_get_type ())
+#define OTTIE_COMPOSITION(o)           (G_TYPE_CHECK_INSTANCE_CAST ((o), OTTIE_TYPE_COMPOSITION, OttieComposition))
+#define OTTIE_COMPOSITION_CLASS(k)     (G_TYPE_CHECK_CLASS_CAST ((k), OTTIE_TYPE_COMPOSITION, OttieCompositionClass))
+#define OTTIE_IS_COMPOSITION(o)        (G_TYPE_CHECK_INSTANCE_TYPE ((o), OTTIE_TYPE_COMPOSITION))
+#define OTTIE_IS_COMPOSITION_CLASS(k)  (G_TYPE_CHECK_CLASS_TYPE ((k), OTTIE_TYPE_COMPOSITION))
+#define OTTIE_COMPOSITION_GET_CLASS(o) (G_TYPE_INSTANCE_GET_CLASS ((o), OTTIE_TYPE_COMPOSITION, OttieCompositionClass))
+
+typedef struct _OttieComposition OttieComposition;
+typedef struct _OttieCompositionClass OttieCompositionClass;
+
+GType                   ottie_composition_get_type          (void) G_GNUC_CONST;
+
+gboolean                ottie_composition_parse_layers      (JsonReader                 *reader,
+                                                             gsize                       offset,
+                                                             gpointer                    data);
+
+G_END_DECLS
+
+#endif /* __OTTIE_COMPOSITION_PRIVATE_H__ */

ottie/ottiecreation.c

@@ -0,0 +1,746 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#include "config.h"
+
+#include "ottiecreationprivate.h"
+
+#include "ottielayerprivate.h"
+#include "ottieparserprivate.h"
+#include "ottiecompositionprivate.h"
+
+#include <glib/gi18n-lib.h>
+#include <json-glib/json-glib.h>
+
+struct _OttieCreation
+{
+  GObject parent;
+
+  char *name;
+  double frame_rate;
+  double start_frame;
+  double end_frame;
+  double width;
+  double height;
+
+  OttieComposition *layers;
+  GHashTable *composition_assets;
+
+  GCancellable *cancellable;
+};
+
+struct _OttieCreationClass
+{
+  GObjectClass parent_class;
+};
+
+enum {
+  PROP_0,
+  PROP_END_FRAME,
+  PROP_FRAME_RATE,
+  PROP_HEIGHT,
+  PROP_LOADING,
+  PROP_NAME,
+  PROP_PREPARED,
+  PROP_START_FRAME,
+  PROP_WIDTH,
+
+  N_PROPS
+};
+
+static GParamSpec *properties[N_PROPS] = { NULL, };
+
+G_DEFINE_TYPE (OttieCreation, ottie_creation, G_TYPE_OBJECT)
+
+static void
+ottie_creation_set_property (GObject      *object,
+                             guint         prop_id,
+                             const GValue *value,
+                             GParamSpec   *pspec)
+
+{
+  //OttieCreation *self = OTTIE_CREATION (object);
+
+  switch (prop_id)
+    {
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void
+ottie_creation_get_property (GObject    *object,
+                             guint       prop_id,
+                             GValue     *value,
+                             GParamSpec *pspec)
+{
+  OttieCreation *self = OTTIE_CREATION (object);
+
+  switch (prop_id)
+    {
+    case PROP_END_FRAME:
+      g_value_set_double (value, self->end_frame);
+      break;
+
+    case PROP_FRAME_RATE:
+      g_value_set_double (value, self->frame_rate);
+      break;
+
+    case PROP_HEIGHT:
+      g_value_set_double (value, self->height);
+      break;
+
+    case PROP_PREPARED:
+      g_value_set_boolean (value, self->cancellable != NULL);
+      break;
+
+    case PROP_NAME:
+      g_value_set_string (value, self->name);
+      break;
+
+    case PROP_START_FRAME:
+      g_value_set_double (value, self->start_frame);
+      break;
+
+    case PROP_WIDTH:
+      g_value_set_double (value, self->width);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void
+ottie_creation_stop_loading (OttieCreation *self,
+                             gboolean       emit)
+{
+  if (self->cancellable == NULL)
+    return;
+
+  g_cancellable_cancel (self->cancellable);
+  g_clear_object (&self->cancellable);
+
+  if (emit)
+    g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_LOADING]);
+}
+
+static void
+ottie_creation_reset (OttieCreation *self)
+{
+  g_clear_object (&self->layers);
+  g_hash_table_remove_all (self->composition_assets);
+
+  g_clear_pointer (&self->name, g_free);
+  self->frame_rate = 0;
+  self->start_frame = 0;
+  self->end_frame = 0;
+  self->width = 0;
+  self->height = 0;
+}
+
+static void
+ottie_creation_dispose (GObject *object)
+{
+  OttieCreation *self = OTTIE_CREATION (object);
+
+  ottie_creation_stop_loading (self, FALSE);
+  ottie_creation_reset (self);
+
+  G_OBJECT_CLASS (ottie_creation_parent_class)->dispose (object);
+}
+
+static void
+ottie_creation_finalize (GObject *object)
+{
+  OttieCreation *self = OTTIE_CREATION (object);
+
+  g_hash_table_unref (self->composition_assets);
+
+  G_OBJECT_CLASS (ottie_creation_parent_class)->finalize (object);
+}
+
+static void
+ottie_creation_class_init (OttieCreationClass *class)
+{
+  GObjectClass *gobject_class = G_OBJECT_CLASS (class);
+
+  gobject_class->set_property = ottie_creation_set_property;
+  gobject_class->get_property = ottie_creation_get_property;
+  gobject_class->finalize = ottie_creation_finalize;
+  gobject_class->dispose = ottie_creation_dispose;
+
+  /**
+   * OttieCreation:end-frame:
+   *
+   * End frame of the creation
+   */
+  properties[PROP_END_FRAME] =
+    g_param_spec_double ("end-frame",
+                         "End frame",
+                         "End frame of the creation",
+                         0.0, G_MAXDOUBLE, 0.0,
+                         G_PARAM_READABLE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
+  /**
+   * OttieCreation:loading:
+   *
+   * Whether the creation is currently loading.
+   */
+  properties[PROP_LOADING] =
+    g_param_spec_boolean ("loading",
+                          "Loading",
+                          "Whether the creation is currently loading",
+                          FALSE,
+                          G_PARAM_READABLE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
+  /**
+   * OttieCreation:frame-rate:
+   *
+   * Frame rate of this creation
+   */
+  properties[PROP_FRAME_RATE] =
+    g_param_spec_double ("frame-rate",
+                         "Frame rate",
+                         "Frame rate of this creation",
+                         0.0, G_MAXDOUBLE, 0.0,
+                         G_PARAM_READABLE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
+  /**
+   * OttieCreation:height:
+   *
+   * Height of this creation
+   */
+  properties[PROP_HEIGHT] =
+    g_param_spec_double ("height",
+                         "Height",
+                         "Height of this creation",
+                         0.0, G_MAXDOUBLE, 0.0,
+                         G_PARAM_READABLE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
+  /**
+   * OttieCreation:name:
+   *
+   * The name of the creation.
+   */
+  properties[PROP_NAME] =
+    g_param_spec_string ("name",
+                         "Name",
+                         "The name of the creation",
+                         NULL,
+                         G_PARAM_READABLE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
+  /**
+   * OttieCreation:prepared:
+   *
+   * Whether the creation is prepared to render
+   */
+  properties[PROP_PREPARED] =
+    g_param_spec_boolean ("prepared",
+                          "Prepared",
+                          "Whether the creation is prepared to render",
+                          FALSE,
+                          G_PARAM_READABLE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
+  /**
+   * OttieCreation:start-frame:
+   *
+   * Start frame of the creation
+   */
+  properties[PROP_START_FRAME] =
+    g_param_spec_double ("start-frame",
+                         "Start frame",
+                         "Start frame of the creation",
+                         0.0, G_MAXDOUBLE, 0.0,
+                         G_PARAM_READABLE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
+  /**
+   * OttieCreation:width:
+   *
+   * Width of this creation
+   */
+  properties[PROP_WIDTH] =
+    g_param_spec_double ("width",
+                         "Width",
+                         "Width of this creation",
+                         0.0, G_MAXDOUBLE, 0.0,
+                         G_PARAM_READABLE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
+  g_object_class_install_properties (gobject_class, N_PROPS, properties);
+}
+
+static void
+ottie_creation_init (OttieCreation *self)
+{
+  self->composition_assets = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, g_object_unref);
+}
+
+/**
+ * ottie_creation_is_loading:
+ * @self: a #OttieCreation
+ *
+ * Returns whether @self is still in the process of loading. This may not just involve
+ * the creation itself, but also any assets that are a part of the creation.
+ *
+ * Returns: %TRUE if the creation is loading
+ */
+gboolean
+ottie_creation_is_loading (OttieCreation *self)
+{
+  g_return_val_if_fail (OTTIE_IS_CREATION (self), FALSE);
+
+  return self->cancellable != NULL;
+}
+
+/**
+ * ottie_creation_is_prepared:
+ * @self: a #OttieCreation
+ *
+ * Returns whether @self has successfully loaded a document that it can display.
+ *
+ * Returns: %TRUE if the creation can be used
+ */
+gboolean
+ottie_creation_is_prepared (OttieCreation *self)
+{
+  g_return_val_if_fail (OTTIE_IS_CREATION (self), FALSE);
+
+  return self->frame_rate > 0;
+}
+
+/**
+ * ottie_creation_get_name:
+ * @self: a #OttieCreation
+ *
+ * Returns the name of the current creation or %NULL if the creation is unnamed.
+ *
+ * Returns: (allow-none): The name of the creation
+ */
+const char *
+ottie_creation_get_name (OttieCreation *self)
+{
+  g_return_val_if_fail (OTTIE_IS_CREATION (self), FALSE);
+
+  return self->name;
+}
+
+static void
+ottie_creation_emit_error (OttieCreation *self,
+                           const GError  *error)
+{
+  g_print ("Ottie is sad: %s\n", error->message);
+}
+
+typedef struct {
+  char *id;
+  OttieComposition *composition;
+} OttieParserAsset;
+
+static gboolean
+ottie_creation_parse_asset (JsonReader *reader,
+                            gsize       offset,
+                            gpointer    data)
+{
+  OttieParserOption options[] = {
+    { "id", ottie_parser_option_string, G_STRUCT_OFFSET (OttieParserAsset, id) },
+    { "layers", ottie_composition_parse_layers, G_STRUCT_OFFSET (OttieParserAsset, composition) },
+  };
+  OttieCreation *self = data;
+  OttieParserAsset asset = { };
+  gboolean result;
+
+  result = ottie_parser_parse_object (reader, "asset", options, G_N_ELEMENTS (options), &asset);
+
+  if (result)
+    {
+      if (asset.id == NULL)
+        ottie_parser_error_syntax (reader, "No name given to asset");
+      else if (asset.composition == NULL)
+        ottie_parser_error_syntax (reader, "No composition layer or image asset defined for name %s", asset.id);
+      else
+        g_hash_table_insert (self->composition_assets, g_strdup (asset.id), g_object_ref (asset.composition));
+    }
+  
+  g_clear_pointer (&asset.id, g_free);
+  g_clear_object (&asset.composition);
+
+  return result;
+}
+
+static gboolean
+ottie_creation_parse_assets (JsonReader *reader,
+                             gsize       offset,
+                             gpointer    data)
+{
+  return ottie_parser_parse_array (reader, "assets",
+                                   0, G_MAXUINT, NULL,
+                                   offset, 0,
+                                   ottie_creation_parse_asset,
+                                   data);
+}
+
+static gboolean
+ottie_creation_parse_marker (JsonReader *reader,
+                             gsize       offset,
+                             gpointer    data)
+{
+  ottie_parser_error_unsupported (reader, "Markers are not implemented yet.");
+
+  return TRUE;
+}
+
+static gboolean
+ottie_creation_parse_markers (JsonReader *reader,
+                              gsize       offset,
+                              gpointer    data)
+{
+  return ottie_parser_parse_array (reader, "markers",
+                                   0, G_MAXUINT, NULL,
+                                   offset, 0,
+                                   ottie_creation_parse_marker,
+                                   data);
+}
+
+static gboolean
+ottie_creation_load_from_reader (OttieCreation *self,
+                                 JsonReader    *reader)
+{
+  OttieParserOption options[] = {
+    { "fr", ottie_parser_option_double, G_STRUCT_OFFSET (OttieCreation, frame_rate) },
+    { "w", ottie_parser_option_double, G_STRUCT_OFFSET (OttieCreation, width) },
+    { "h", ottie_parser_option_double, G_STRUCT_OFFSET (OttieCreation, height) },
+    { "nm", ottie_parser_option_string, G_STRUCT_OFFSET (OttieCreation, name) },
+    { "ip", ottie_parser_option_double, G_STRUCT_OFFSET (OttieCreation, start_frame) },
+    { "op", ottie_parser_option_double, G_STRUCT_OFFSET (OttieCreation, end_frame) },
+    { "ddd", ottie_parser_option_3d, 0 },
+    { "v", ottie_parser_option_skip, 0 },
+    { "layers", ottie_composition_parse_layers, G_STRUCT_OFFSET (OttieCreation, layers) },
+    { "assets", ottie_creation_parse_assets, 0 },
+    { "markers", ottie_creation_parse_markers, 0 },
+  };
+
+  return ottie_parser_parse_object (reader, "toplevel", options, G_N_ELEMENTS (options), self);
+}
+
+static void
+ottie_creation_update_layers (OttieCreation *self)
+{
+  GHashTableIter iter;
+  gpointer layer;
+
+  g_hash_table_iter_init (&iter, self->composition_assets);
+
+  while (g_hash_table_iter_next (&iter, NULL, &layer))
+    ottie_layer_update (layer, self->composition_assets);
+
+  ottie_layer_update (OTTIE_LAYER (self->layers), self->composition_assets);
+}
+
+static void
+ottie_creation_notify_prepared (OttieCreation *self)
+{
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_PREPARED]);
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_FRAME_RATE]);
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_WIDTH]);
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_HEIGHT]);
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_START_FRAME]);
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_END_FRAME]);
+}
+
+static gboolean
+ottie_creation_load_from_node (OttieCreation *self, 
+                               JsonNode      *root)
+{
+  JsonReader *reader = json_reader_new (root);
+  gboolean result;
+
+  result = ottie_creation_load_from_reader (self, reader);
+
+  g_object_unref (reader);
+
+  return result;
+}
+
+static void
+ottie_creation_load_file_parsed (GObject      *parser,
+                                 GAsyncResult *res,
+                                 gpointer      data)
+{
+  OttieCreation *self = data;
+  GError *error = NULL;
+
+  if (!json_parser_load_from_stream_finish (JSON_PARSER (parser), res, &error))
+    {
+      if (g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
+        return;
+
+      ottie_creation_emit_error (self, error);
+      g_error_free (error);
+      ottie_creation_stop_loading (self, TRUE);
+      return;
+    }
+
+  g_object_freeze_notify (G_OBJECT (self));
+
+  if (ottie_creation_load_from_node (self, json_parser_get_root (JSON_PARSER (parser))))
+    {
+      ottie_creation_update_layers (self);
+    }
+  else
+    {
+      ottie_creation_reset (self);
+    }
+
+  ottie_creation_stop_loading (self, TRUE);
+  ottie_creation_notify_prepared (self);
+
+  g_object_thaw_notify (G_OBJECT (self));
+}
+
+static void
+ottie_creation_load_file_open (GObject      *file,
+                               GAsyncResult *res,
+                               gpointer      data)
+{
+  OttieCreation *self = data;
+  GFileInputStream *stream;
+  GError *error = NULL;
+  JsonParser *parser;
+
+  stream = g_file_read_finish (G_FILE (file), res, &error);
+  if (stream == NULL)
+    {
+      if (g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
+        return;
+
+      ottie_creation_emit_error (self, error);
+      g_error_free (error);
+      ottie_creation_stop_loading (self, TRUE);
+      return;
+    }
+
+  parser = json_parser_new ();
+  json_parser_load_from_stream_async (parser,
+                                      G_INPUT_STREAM (stream), 
+                                      self->cancellable,
+                                      ottie_creation_load_file_parsed,
+                                      self);
+  g_object_unref (parser);
+}
+
+void
+ottie_creation_load_bytes (OttieCreation *self,
+                           GBytes        *bytes)
+{
+  GError *error = NULL;
+  JsonParser *parser;
+
+  g_return_if_fail (OTTIE_IS_CREATION (self));
+  g_return_if_fail (bytes != NULL);
+
+  g_object_freeze_notify (G_OBJECT (self));
+
+  ottie_creation_stop_loading (self, FALSE);
+  ottie_creation_reset (self);
+
+  parser = json_parser_new ();
+  if (json_parser_load_from_data (parser,
+                                  g_bytes_get_data (bytes, NULL),
+                                  g_bytes_get_size (bytes),
+                                  &error))
+    {
+      if (ottie_creation_load_from_node (self, json_parser_get_root (JSON_PARSER (parser))))
+        {
+          ottie_creation_update_layers (self);
+        }
+      else
+        {
+          ottie_creation_reset (self);
+        }
+    }
+  else
+    {
+      ottie_creation_emit_error (self, error);
+      g_error_free (error);
+    }
+
+  g_object_unref (parser);
+
+  ottie_creation_notify_prepared (self);
+
+  g_object_thaw_notify (G_OBJECT (self));
+}
+
+void
+ottie_creation_load_file (OttieCreation *self,
+                          GFile         *file)
+{
+  g_return_if_fail (OTTIE_IS_CREATION (self));
+  g_return_if_fail (G_IS_FILE (file));
+
+  g_object_freeze_notify (G_OBJECT (self));
+
+  ottie_creation_stop_loading (self, FALSE);
+  if (self->frame_rate)
+    {
+      ottie_creation_reset (self);
+      ottie_creation_notify_prepared (self);
+    }
+
+  self->cancellable = g_cancellable_new ();
+
+  g_file_read_async (file,
+                     G_PRIORITY_DEFAULT,
+                     self->cancellable,
+                     ottie_creation_load_file_open,
+                     self);
+
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_LOADING]);
+
+  g_object_thaw_notify (G_OBJECT (self));
+}
+
+void
+ottie_creation_load_filename (OttieCreation *self,
+                              const char    *filename)
+{
+  GFile *file;
+
+  g_return_if_fail (OTTIE_IS_CREATION (self));
+  g_return_if_fail (filename != NULL);
+
+  file = g_file_new_for_path (filename);
+
+  ottie_creation_load_file (self, file);
+
+  g_clear_object (&file);
+}
+
+OttieCreation *
+ottie_creation_new (void)
+{
+  return g_object_new (OTTIE_TYPE_CREATION, NULL);
+}
+
+OttieCreation *
+ottie_creation_new_for_file (GFile *file)
+{
+  OttieCreation *self;
+
+  g_return_val_if_fail (G_IS_FILE (file), NULL);
+
+  self = g_object_new (OTTIE_TYPE_CREATION, NULL);
+
+  ottie_creation_load_file (self, file);
+
+  return self;
+}
+
+OttieCreation *
+ottie_creation_new_for_filename (const char *filename)
+{
+  OttieCreation *self;
+  GFile *file;
+
+  g_return_val_if_fail (filename != NULL, NULL);
+
+  file = g_file_new_for_path (filename);
+
+  self = ottie_creation_new_for_file (file);
+
+  g_clear_object (&file);
+
+  return self;
+}
+
+double
+ottie_creation_get_frame_rate (OttieCreation *self)
+{
+  g_return_val_if_fail (OTTIE_IS_CREATION (self), 0);
+
+  return self->frame_rate;
+}
+
+double
+ottie_creation_get_start_frame (OttieCreation *self)
+{
+  g_return_val_if_fail (OTTIE_IS_CREATION (self), 0);
+
+  return self->start_frame;
+}
+
+double
+ottie_creation_get_end_frame (OttieCreation *self)
+{
+  g_return_val_if_fail (OTTIE_IS_CREATION (self), 0);
+
+  return self->end_frame;
+}
+
+double
+ottie_creation_get_width (OttieCreation *self)
+{
+  g_return_val_if_fail (OTTIE_IS_CREATION (self), 0);
+
+  return self->width;
+}
+
+double
+ottie_creation_get_height (OttieCreation *self)
+{
+  g_return_val_if_fail (OTTIE_IS_CREATION (self), 0);
+
+  return self->height;
+}
+
+void
+ottie_creation_snapshot (OttieCreation *self,
+                         GtkSnapshot   *snapshot,
+                         double         timestamp)
+{
+  GskRenderNode *node;
+  OttieRender render;
+
+  if (self->layers == NULL)
+    return;
+
+  timestamp = timestamp * self->frame_rate;
+
+  ottie_render_init (&render);
+
+  ottie_layer_render (OTTIE_LAYER (self->layers), &render, timestamp);
+  node = ottie_render_get_node (&render);
+  if (node)
+    {
+      gtk_snapshot_append_node (snapshot, node);
+      gsk_render_node_unref (node);
+    }
+
+  ottie_render_clear (&render);
+}
+
+OttieComposition *
+ottie_creation_get_composition (OttieCreation *self)
+{
+  return self->layers;
+}
+

ottie/ottiecreation.h

@@ -0,0 +1,83 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#ifndef __OTTIE_CREATION_H__
+#define __OTTIE_CREATION_H__
+
+#if !defined (__OTTIE_H_INSIDE__) && !defined (GTK_COMPILATION)
+#error "Only <ottie/ottie.h> can be included directly."
+#endif
+
+#include <gdk/gdk.h>
+
+G_BEGIN_DECLS
+
+#define OTTIE_TYPE_CREATION         (ottie_creation_get_type ())
+#define OTTIE_CREATION(o)           (G_TYPE_CHECK_INSTANCE_CAST ((o), OTTIE_TYPE_CREATION, OttieCreation))
+#define OTTIE_CREATION_CLASS(k)     (G_TYPE_CHECK_CLASS_CAST ((k), OTTIE_TYPE_CREATION, OttieCreationClass))
+#define OTTIE_IS_CREATION(o)        (G_TYPE_CHECK_INSTANCE_TYPE ((o), OTTIE_TYPE_CREATION))
+#define OTTIE_IS_CREATION_CLASS(k)  (G_TYPE_CHECK_CLASS_TYPE ((k), OTTIE_TYPE_CREATION))
+#define OTTIE_CREATION_GET_CLASS(o) (G_TYPE_INSTANCE_GET_CLASS ((o), OTTIE_TYPE_CREATION, OttieCreationClass))
+
+typedef struct _OttieCreation OttieCreation;
+typedef struct _OttieCreationClass OttieCreationClass;
+
+GDK_AVAILABLE_IN_ALL
+GType                   ottie_creation_get_type                 (void) G_GNUC_CONST;
+
+GDK_AVAILABLE_IN_ALL
+OttieCreation *         ottie_creation_new                      (void);
+GDK_AVAILABLE_IN_ALL
+OttieCreation *         ottie_creation_new_for_file             (GFile                  *file);
+GDK_AVAILABLE_IN_ALL
+OttieCreation *         ottie_creation_new_for_filename         (const char             *filename);
+
+GDK_AVAILABLE_IN_ALL
+void                    ottie_creation_load_file                (OttieCreation          *self,
+                                                                 GFile                  *file);
+GDK_AVAILABLE_IN_ALL
+void                    ottie_creation_load_filename            (OttieCreation          *self,
+                                                                 const char             *filename);
+GDK_AVAILABLE_IN_ALL
+void                    ottie_creation_load_bytes               (OttieCreation          *self,
+                                                                 GBytes                 *bytes);
+
+GDK_AVAILABLE_IN_ALL
+gboolean                ottie_creation_is_loading               (OttieCreation          *self);
+GDK_AVAILABLE_IN_ALL
+gboolean                ottie_creation_is_prepared              (OttieCreation          *self);
+
+GDK_AVAILABLE_IN_ALL
+const char *            ottie_creation_get_name                 (OttieCreation          *self);
+GDK_AVAILABLE_IN_ALL
+double                  ottie_creation_get_frame_rate           (OttieCreation          *self);
+GDK_AVAILABLE_IN_ALL
+double                  ottie_creation_get_start_frame          (OttieCreation          *self);
+GDK_AVAILABLE_IN_ALL
+double                  ottie_creation_get_end_frame            (OttieCreation          *self);
+GDK_AVAILABLE_IN_ALL
+double                  ottie_creation_get_width                (OttieCreation          *self);
+GDK_AVAILABLE_IN_ALL
+double                  ottie_creation_get_height               (OttieCreation          *self);
+
+
+
+G_END_DECLS
+
+#endif /* __OTTIE_CREATION_H__ */

ottie/ottiecreationprivate.h

@@ -0,0 +1,40 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#ifndef __OTTIE_CREATION_PRIVATE_H__
+#define __OTTIE_CREATION_PRIVATE_H__
+
+#include "ottiecreation.h"
+
+#include "ottiecompositionprivate.h"
+
+#include <gtk/gtk.h>
+
+G_BEGIN_DECLS
+
+
+void                    ottie_creation_snapshot                 (OttieCreation          *self,
+                                                                 GtkSnapshot            *snapshot,
+                                                                 double                  timestamp);
+
+OttieComposition *      ottie_creation_get_composition          (OttieCreation          *self);
+
+G_END_DECLS
+
+#endif /* __OTTIE_CREATION_PRIVATE_H__ */

ottie/ottiedoublevalue.c

@@ -0,0 +1,121 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#include "config.h"
+
+#include "ottiedoublevalueprivate.h"
+
+#include "ottieparserprivate.h"
+
+#include <glib/gi18n-lib.h>
+
+static gboolean
+ottie_double_value_parse_value (JsonReader *reader,
+                                gsize       offset,
+                                gpointer    data)
+{
+  gboolean result, array;
+
+  /* Lottie being Lottie, single values may get dumped into arrays. */
+  array = json_reader_is_array (reader);
+  if (array)
+    json_reader_read_element (reader, 0);
+
+  result = ottie_parser_option_double (reader, offset, data);
+
+  if (array)
+    json_reader_end_element (reader);
+
+  return result;
+}
+
+static double
+ottie_double_value_interpolate (double start,
+                                double end,
+                                double progress)
+{
+  return start + (end - start) * progress;
+}
+
+#define OTTIE_KEYFRAMES_NAME ottie_double_keyframes
+#define OTTIE_KEYFRAMES_TYPE_NAME OttieDoubleKeyframes
+#define OTTIE_KEYFRAMES_ELEMENT_TYPE double
+#define OTTIE_KEYFRAMES_PARSE_FUNC ottie_double_value_parse_value
+#define OTTIE_KEYFRAMES_INTERPOLATE_FUNC ottie_double_value_interpolate
+#include "ottiekeyframesimpl.c"
+
+void
+ottie_double_value_init (OttieDoubleValue *self,
+                         double            value)
+{
+  self->is_static = TRUE;
+  self->static_value = value;
+}
+
+void
+ottie_double_value_clear (OttieDoubleValue *self)
+{
+  if (!self->is_static)
+    g_clear_pointer (&self->keyframes, ottie_double_keyframes_free);
+}
+
+double
+ottie_double_value_get (OttieDoubleValue *self,
+                        double            timestamp)
+{
+  if (self->is_static)
+    return self->static_value;
+  
+  return ottie_double_keyframes_get (self->keyframes, timestamp);
+}
+
+gboolean
+ottie_double_value_parse (JsonReader *reader,
+                          gsize       offset,
+                          gpointer    data)
+{
+  OttieDoubleValue *self = (OttieDoubleValue *) ((guint8 *) data + GPOINTER_TO_SIZE (offset));
+
+  if (json_reader_read_member (reader, "k"))
+    {
+      if (!json_reader_is_array (reader))
+        {
+          self->is_static = TRUE;
+          self->static_value = json_reader_get_double_value (reader);
+        }
+      else
+        {
+          self->is_static = FALSE;
+          self->keyframes = ottie_double_keyframes_parse (reader);
+          if (self->keyframes == NULL)
+            {
+              json_reader_end_member (reader);
+              return FALSE;
+            }
+        }
+    }
+  else
+    {
+      ottie_parser_error_syntax (reader, "Property is not a number");
+    }
+  json_reader_end_member (reader);
+
+  return TRUE;
+}
+

ottie/ottiedoublevalueprivate.h

@@ -0,0 +1,58 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#ifndef __OTTIE_DOUBLE_VALUE_PRIVATE_H__
+#define __OTTIE_DOUBLE_VALUE_PRIVATE_H__
+
+#include <json-glib/json-glib.h>
+
+G_BEGIN_DECLS
+
+typedef struct _OttieDoubleValue OttieDoubleValue;
+
+struct _OttieDoubleValue
+{
+  gboolean is_static;
+  union {
+    double static_value;
+    gpointer keyframes;
+  };
+};
+
+void                      ottie_double_value_init               (OttieDoubleValue       *self,
+                                                                 double                  value);
+void                      ottie_double_value_clear              (OttieDoubleValue       *self);
+
+static inline gboolean    ottie_double_value_is_static          (OttieDoubleValue       *self);
+double                    ottie_double_value_get                (OttieDoubleValue       *self,
+                                                                 double                  timestamp);
+
+gboolean                  ottie_double_value_parse              (JsonReader             *reader,
+                                                                 gsize                   offset,
+                                                                 gpointer                data);
+
+static inline gboolean
+ottie_double_value_is_static (OttieDoubleValue *self)
+{
+  return self->is_static;
+}
+
+G_END_DECLS
+
+#endif /* __OTTIE_DOUBLE_VALUE_PRIVATE_H__ */

ottie/ottieellipseshape.c

@@ -0,0 +1,138 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#include "config.h"
+
+#include "ottieellipseshapeprivate.h"
+
+#include "ottiedoublevalueprivate.h"
+#include "ottiepointvalueprivate.h"
+#include "ottieparserprivate.h"
+#include "ottieshapeprivate.h"
+
+#include <glib/gi18n-lib.h>
+
+struct _OttieEllipseShape
+{
+  OttieShape parent;
+
+  double diellipseion;
+  OttiePointValue position;
+  OttiePointValue size;
+};
+
+struct _OttieEllipseShapeClass
+{
+  OttieShapeClass parent_class;
+};
+
+G_DEFINE_TYPE (OttieEllipseShape, ottie_ellipse_shape, OTTIE_TYPE_SHAPE)
+
+static void
+ottie_ellipse_shape_render (OttieShape  *shape,
+                         OttieRender *render,
+                         double       timestamp)
+{
+  OttieEllipseShape *self = OTTIE_ELLIPSE_SHAPE (shape);
+  graphene_point_t p, s;
+  GskPathBuilder *builder;
+  const float weight = sqrt(0.5f);
+
+  ottie_point_value_get (&self->position, timestamp, &p);
+  ottie_point_value_get (&self->size, timestamp, &s);
+  s.x /= 2;
+  s.y /= 2;
+
+  builder = gsk_path_builder_new ();
+
+  gsk_path_builder_move_to (builder,
+                            p.x, p.y - s.y);
+  gsk_path_builder_conic_to (builder,
+                             p.x + s.x, p.y - s.y,
+                             p.x + s.x, p.y,
+                             weight);
+  gsk_path_builder_conic_to (builder,
+                             p.x + s.x, p.y + s.y,
+                             p.x, p.y + s.y,
+                             weight);
+  gsk_path_builder_conic_to (builder,
+                             p.x - s.x, p.y + s.y,
+                             p.x - s.x, p.y,
+                             weight);
+  gsk_path_builder_conic_to (builder,
+                             p.x - s.x, p.y - s.y,
+                             p.x, p.y - s.y,
+                             weight);
+  gsk_path_builder_close (builder);
+
+  ottie_render_add_path (render,
+                         gsk_path_builder_free_to_path (builder));
+}
+
+static void
+ottie_ellipse_shape_dispose (GObject *object)
+{
+  OttieEllipseShape *self = OTTIE_ELLIPSE_SHAPE (object);
+
+  ottie_point_value_clear (&self->position);
+  ottie_point_value_clear (&self->size);
+
+  G_OBJECT_CLASS (ottie_ellipse_shape_parent_class)->dispose (object);
+}
+
+static void
+ottie_ellipse_shape_class_init (OttieEllipseShapeClass *klass)
+{
+  OttieShapeClass *shape_class = OTTIE_SHAPE_CLASS (klass);
+  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
+
+  shape_class->render = ottie_ellipse_shape_render;
+
+  gobject_class->dispose = ottie_ellipse_shape_dispose;
+}
+
+static void
+ottie_ellipse_shape_init (OttieEllipseShape *self)
+{
+  ottie_point_value_init (&self->position, &GRAPHENE_POINT_INIT (0, 0));
+  ottie_point_value_init (&self->size, &GRAPHENE_POINT_INIT (0, 0));
+}
+
+OttieShape *
+ottie_ellipse_shape_parse (JsonReader *reader)
+{
+  OttieParserOption options[] = {
+    OTTIE_PARSE_OPTIONS_SHAPE,
+    { "d", ottie_parser_option_double, G_STRUCT_OFFSET (OttieEllipseShape, diellipseion) },
+    { "p", ottie_point_value_parse, G_STRUCT_OFFSET (OttieEllipseShape, position) },
+    { "s", ottie_point_value_parse, G_STRUCT_OFFSET (OttieEllipseShape, size) },
+  };
+  OttieEllipseShape *self;
+
+  self = g_object_new (OTTIE_TYPE_ELLIPSE_SHAPE, NULL);
+
+  if (!ottie_parser_parse_object (reader, "ellipse shape", options, G_N_ELEMENTS (options), self))
+    {
+      g_object_unref (self);
+      return NULL;
+    }
+
+  return OTTIE_SHAPE (self);
+}
+

ottie/ottieellipseshapeprivate.h

@@ -0,0 +1,45 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#ifndef __OTTIE_ELLIPSE_SHAPE_PRIVATE_H__
+#define __OTTIE_ELLIPSE_SHAPE_PRIVATE_H__
+
+#include "ottieshapeprivate.h"
+
+#include <json-glib/json-glib.h>
+
+G_BEGIN_DECLS
+
+#define OTTIE_TYPE_ELLIPSE_SHAPE         (ottie_ellipse_shape_get_type ())
+#define OTTIE_ELLIPSE_SHAPE(o)           (G_TYPE_CHECK_INSTANCE_CAST ((o), OTTIE_TYPE_ELLIPSE_SHAPE, OttieEllipseShape))
+#define OTTIE_ELLIPSE_SHAPE_CLASS(k)     (G_TYPE_CHECK_CLASS_CAST ((k), OTTIE_TYPE_ELLIPSE_SHAPE, OttieEllipseShapeClass))
+#define OTTIE_IS_ELLIPSE_SHAPE(o)        (G_TYPE_CHECK_INSTANCE_TYPE ((o), OTTIE_TYPE_ELLIPSE_SHAPE))
+#define OTTIE_IS_ELLIPSE_SHAPE_CLASS(k)  (G_TYPE_CHECK_CLASS_TYPE ((k), OTTIE_TYPE_ELLIPSE_SHAPE))
+#define OTTIE_ELLIPSE_SHAPE_GET_CLASS(o) (G_TYPE_INSTANCE_GET_CLASS ((o), OTTIE_TYPE_ELLIPSE_SHAPE, OttieEllipseShapeClass))
+
+typedef struct _OttieEllipseShape OttieEllipseShape;
+typedef struct _OttieEllipseShapeClass OttieEllipseShapeClass;
+
+GType                   ottie_ellipse_shape_get_type            (void) G_GNUC_CONST;
+
+OttieShape *            ottie_ellipse_shape_parse               (JsonReader             *reader);
+
+G_END_DECLS
+
+#endif /* __OTTIE_ELLIPSE_SHAPE_PRIVATE_H__ */

ottie/ottiefillshape.c

@@ -0,0 +1,132 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#include "config.h"
+
+#include "ottiefillshapeprivate.h"
+
+#include "ottiecolorvalueprivate.h"
+#include "ottiedoublevalueprivate.h"
+#include "ottieparserprivate.h"
+#include "ottieshapeprivate.h"
+
+#include <glib/gi18n-lib.h>
+#include <gsk/gsk.h>
+
+struct _OttieFillShape
+{
+  OttieShape parent;
+
+  OttieDoubleValue opacity;
+  OttieColorValue color;
+  GskBlendMode blend_mode;
+  GskFillRule fill_rule;
+};
+
+struct _OttieFillShapeClass
+{
+  OttieShapeClass parent_class;
+};
+
+G_DEFINE_TYPE (OttieFillShape, ottie_fill_shape, OTTIE_TYPE_SHAPE)
+
+static void
+ottie_fill_shape_render (OttieShape  *shape,
+                         OttieRender *render,
+                         double       timestamp)
+{
+  OttieFillShape *self = OTTIE_FILL_SHAPE (shape);
+  GskPath *path;
+  graphene_rect_t bounds;
+  GdkRGBA color;
+  double opacity;
+  GskRenderNode *color_node;
+
+  opacity = ottie_double_value_get (&self->opacity, timestamp);
+  opacity = CLAMP (opacity, 0, 100);
+  ottie_color_value_get (&self->color, timestamp, &color);
+  color.alpha = color.alpha * opacity / 100.f;
+  if (gdk_rgba_is_clear (&color))
+    return;
+
+  path = ottie_render_get_path (render);
+  if (gsk_path_is_empty (path))
+    return;
+
+  gsk_path_get_bounds (path, &bounds);
+  color_node = gsk_color_node_new (&color, &bounds);
+
+  ottie_render_add_node (render, gsk_fill_node_new (color_node, path, self->fill_rule));
+
+  gsk_render_node_unref (color_node);
+}
+
+static void
+ottie_fill_shape_dispose (GObject *object)
+{
+  OttieFillShape *self = OTTIE_FILL_SHAPE (object);
+
+  ottie_double_value_clear (&self->opacity);
+  ottie_color_value_clear (&self->color);
+
+  G_OBJECT_CLASS (ottie_fill_shape_parent_class)->dispose (object);
+}
+
+static void
+ottie_fill_shape_class_init (OttieFillShapeClass *klass)
+{
+  OttieShapeClass *shape_class = OTTIE_SHAPE_CLASS (klass);
+  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
+
+  shape_class->render = ottie_fill_shape_render;
+
+  gobject_class->dispose = ottie_fill_shape_dispose;
+}
+
+static void
+ottie_fill_shape_init (OttieFillShape *self)
+{
+  ottie_double_value_init (&self->opacity, 100);
+  ottie_color_value_init (&self->color, &(GdkRGBA) { 0, 0, 0, 1 });
+  self->fill_rule = GSK_FILL_RULE_WINDING;
+}
+
+OttieShape *
+ottie_fill_shape_parse (JsonReader *reader)
+{
+  OttieParserOption options[] = {
+    OTTIE_PARSE_OPTIONS_SHAPE,
+    { "o", ottie_double_value_parse, G_STRUCT_OFFSET (OttieFillShape, opacity) },
+    { "c", ottie_color_value_parse, G_STRUCT_OFFSET (OttieFillShape, color) },
+    { "bm", ottie_parser_option_blend_mode, G_STRUCT_OFFSET (OttieFillShape, blend_mode) },
+    { "r", ottie_parser_option_fill_rule, G_STRUCT_OFFSET (OttieFillShape, fill_rule) },
+  };
+  OttieFillShape *self;
+
+  self = g_object_new (OTTIE_TYPE_FILL_SHAPE, NULL);
+
+  if (!ottie_parser_parse_object (reader, "fill shape", options, G_N_ELEMENTS (options), self))
+    {
+      g_object_unref (self);
+      return NULL;
+    }
+
+  return OTTIE_SHAPE (self);
+}
+

ottie/ottiefillshapeprivate.h

@@ -0,0 +1,45 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#ifndef __OTTIE_FILL_SHAPE_PRIVATE_H__
+#define __OTTIE_FILL_SHAPE_PRIVATE_H__
+
+#include "ottieshapeprivate.h"
+
+#include <json-glib/json-glib.h>
+
+G_BEGIN_DECLS
+
+#define OTTIE_TYPE_FILL_SHAPE         (ottie_fill_shape_get_type ())
+#define OTTIE_FILL_SHAPE(o)           (G_TYPE_CHECK_INSTANCE_CAST ((o), OTTIE_TYPE_FILL_SHAPE, OttieFillShape))
+#define OTTIE_FILL_SHAPE_CLASS(k)     (G_TYPE_CHECK_CLASS_CAST ((k), OTTIE_TYPE_FILL_SHAPE, OttieFillShapeClass))
+#define OTTIE_IS_FILL_SHAPE(o)        (G_TYPE_CHECK_INSTANCE_TYPE ((o), OTTIE_TYPE_FILL_SHAPE))
+#define OTTIE_IS_FILL_SHAPE_CLASS(k)  (G_TYPE_CHECK_CLASS_TYPE ((k), OTTIE_TYPE_FILL_SHAPE))
+#define OTTIE_FILL_SHAPE_GET_CLASS(o) (G_TYPE_INSTANCE_GET_CLASS ((o), OTTIE_TYPE_FILL_SHAPE, OttieFillShapeClass))
+
+typedef struct _OttieFillShape OttieFillShape;
+typedef struct _OttieFillShapeClass OttieFillShapeClass;
+
+GType                   ottie_fill_shape_get_type               (void) G_GNUC_CONST;
+
+OttieShape *            ottie_fill_shape_parse                  (JsonReader             *reader);
+
+G_END_DECLS
+
+#endif /* __OTTIE_FILL_SHAPE_PRIVATE_H__ */

ottie/ottiegroupshape.c

@@ -0,0 +1,247 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#include "config.h"
+
+#include "ottiegroupshapeprivate.h"
+
+#include "ottieellipseshapeprivate.h"
+#include "ottiefillshapeprivate.h"
+#include "ottieparserprivate.h"
+#include "ottiepathshapeprivate.h"
+#include "ottierectshapeprivate.h"
+#include "ottieshapeprivate.h"
+#include "ottiestrokeshapeprivate.h"
+#include "ottietransformprivate.h"
+#include "ottietrimshapeprivate.h"
+
+#include <glib/gi18n-lib.h>
+#include <gsk/gsk.h>
+
+#define GDK_ARRAY_ELEMENT_TYPE OttieShape *
+#define GDK_ARRAY_FREE_FUNC g_object_unref
+#define GDK_ARRAY_TYPE_NAME OttieShapeList
+#define GDK_ARRAY_NAME ottie_shape_list
+#define GDK_ARRAY_PREALLOC 4
+#include "gdk/gdkarrayimpl.c"
+
+struct _OttieGroupShape
+{
+  OttieShape parent;
+
+  OttieShapeList shapes;
+  GskBlendMode blend_mode;
+};
+
+struct _OttieGroupShapeClass
+{
+  OttieShapeClass parent_class;
+};
+
+static GType
+ottie_group_shape_get_item_type (GListModel *list)
+{
+  return OTTIE_TYPE_SHAPE;
+}
+
+static guint
+ottie_group_shape_get_n_items (GListModel *list)
+{
+  OttieGroupShape *self = OTTIE_GROUP_SHAPE (list);
+
+  return ottie_shape_list_get_size (&self->shapes);
+}
+
+static gpointer
+ottie_group_shape_get_item (GListModel *list,
+                            guint       position)
+{
+  OttieGroupShape *self = OTTIE_GROUP_SHAPE (list);
+
+  if (position >= ottie_shape_list_get_size (&self->shapes))
+    return NULL;
+
+  return g_object_ref (ottie_shape_list_get (&self->shapes, position));
+}
+
+static void
+ottie_group_shape_list_model_init (GListModelInterface *iface)
+{
+  iface->get_item_type = ottie_group_shape_get_item_type;
+  iface->get_n_items = ottie_group_shape_get_n_items;
+  iface->get_item = ottie_group_shape_get_item;
+}
+
+G_DEFINE_TYPE_WITH_CODE (OttieGroupShape, ottie_group_shape, OTTIE_TYPE_SHAPE,
+                         G_IMPLEMENT_INTERFACE (G_TYPE_LIST_MODEL, ottie_group_shape_list_model_init))
+
+static void
+ottie_group_shape_render (OttieShape  *shape,
+                          OttieRender *render,
+                          double       timestamp)
+{
+  OttieGroupShape *self = OTTIE_GROUP_SHAPE (shape);
+  OttieRender child_render;
+
+  ottie_render_init (&child_render);
+
+  for (gsize i = 0; i < ottie_shape_list_get_size (&self->shapes); i++)
+    {
+      ottie_shape_render (ottie_shape_list_get (&self->shapes, i),
+                          &child_render,
+                          timestamp);
+    }
+
+  ottie_render_merge (render, &child_render);
+
+  ottie_render_clear (&child_render);
+}
+
+static void
+ottie_group_shape_dispose (GObject *object)
+{
+  OttieGroupShape *self = OTTIE_GROUP_SHAPE (object);
+
+  ottie_shape_list_clear (&self->shapes);
+
+  G_OBJECT_CLASS (ottie_group_shape_parent_class)->dispose (object);
+}
+
+static void
+ottie_group_shape_class_init (OttieGroupShapeClass *klass)
+{
+  OttieShapeClass *shape_class = OTTIE_SHAPE_CLASS (klass);
+  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
+
+  shape_class->render = ottie_group_shape_render;
+
+  gobject_class->dispose = ottie_group_shape_dispose;
+}
+
+static void
+ottie_group_shape_init (OttieGroupShape *self)
+{
+}
+
+gboolean
+ottie_group_shape_parse_shapes (JsonReader *reader,
+                                gsize       offset,
+                                gpointer    data)
+{
+  OttieGroupShape *self = data;
+
+  if (!json_reader_is_array (reader))
+    {
+      ottie_parser_error_syntax (reader, "Shapes are not an array.");
+      return FALSE;
+    }
+
+  for (int i = 0; ; i++)
+    {
+      OttieShape *shape;
+      const char *type;
+
+      if (!json_reader_read_element (reader, i))
+        break;
+
+      if (!json_reader_is_object (reader))
+        {
+          ottie_parser_error_syntax (reader, "Shape %d is not an object", i);
+          continue;
+        }
+
+      if (!json_reader_read_member (reader, "ty"))
+        {
+          ottie_parser_error_syntax (reader, "Shape %d has no type", i);
+          json_reader_end_member (reader);
+          json_reader_end_element (reader);
+          continue;
+        }
+
+      type = json_reader_get_string_value (reader);
+      if (type == NULL || json_reader_get_error (reader))
+        {
+          ottie_parser_emit_error (reader, json_reader_get_error (reader));
+          json_reader_end_member (reader);
+          json_reader_end_element (reader);
+          continue;
+        }
+      json_reader_end_member (reader);
+
+      if (g_str_equal (type, "el"))
+        shape = ottie_ellipse_shape_parse (reader);
+      else if (g_str_equal (type, "fl"))
+        shape = ottie_fill_shape_parse (reader);
+      else if (g_str_equal (type, "gr"))
+        shape = ottie_group_shape_parse (reader);
+      else if (g_str_equal (type, "rc"))
+        shape = ottie_rect_shape_parse (reader);
+      else if (g_str_equal (type, "sh"))
+        shape = ottie_path_shape_parse (reader);
+      else if (g_str_equal (type, "st"))
+        shape = ottie_stroke_shape_parse (reader);
+      else if (g_str_equal (type, "tm"))
+        shape = ottie_trim_shape_parse (reader);
+      else if (g_str_equal (type, "tr"))
+        shape = ottie_transform_parse (reader);
+      else
+        {
+          ottie_parser_error_value (reader, "Shape %d has unknown type \"%s\"", i, type);
+          shape = NULL;
+        }
+
+      if (shape)
+        ottie_shape_list_append (&self->shapes, shape);
+      json_reader_end_element (reader);
+    }
+
+  json_reader_end_element (reader);
+
+  return TRUE;
+}
+
+OttieShape *
+ottie_group_shape_new (void)
+{
+  return g_object_new (OTTIE_TYPE_GROUP_SHAPE, NULL);
+}
+
+OttieShape *
+ottie_group_shape_parse (JsonReader *reader)
+{
+  OttieParserOption options[] = {
+    OTTIE_PARSE_OPTIONS_SHAPE,
+    { "bm", ottie_parser_option_blend_mode, G_STRUCT_OFFSET (OttieGroupShape, blend_mode) },
+    { "np", ottie_parser_option_skip_expression, 0 },
+    { "cix", ottie_parser_option_skip_index, 0 },
+    { "it", ottie_group_shape_parse_shapes, 0 },
+  };
+  OttieShape *self;
+
+  self = ottie_group_shape_new ();
+
+  if (!ottie_parser_parse_object (reader, "group shape", options, G_N_ELEMENTS (options), self))
+    {
+      g_object_unref (self);
+      return NULL;
+    }
+
+  return self;
+}
+

ottie/ottiegroupshapeprivate.h

@@ -0,0 +1,50 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#ifndef __OTTIE_GROUP_SHAPE_PRIVATE_H__
+#define __OTTIE_GROUP_SHAPE_PRIVATE_H__
+
+#include "ottieshapeprivate.h"
+
+#include <json-glib/json-glib.h>
+
+G_BEGIN_DECLS
+
+#define OTTIE_TYPE_GROUP_SHAPE         (ottie_group_shape_get_type ())
+#define OTTIE_GROUP_SHAPE(o)           (G_TYPE_CHECK_INSTANCE_CAST ((o), OTTIE_TYPE_GROUP_SHAPE, OttieGroupShape))
+#define OTTIE_GROUP_SHAPE_CLASS(k)     (G_TYPE_CHECK_CLASS_CAST ((k), OTTIE_TYPE_GROUP_SHAPE, OttieGroupShapeClass))
+#define OTTIE_IS_GROUP_SHAPE(o)        (G_TYPE_CHECK_INSTANCE_TYPE ((o), OTTIE_TYPE_GROUP_SHAPE))
+#define OTTIE_IS_GROUP_SHAPE_CLASS(k)  (G_TYPE_CHECK_CLASS_TYPE ((k), OTTIE_TYPE_GROUP_SHAPE))
+#define OTTIE_GROUP_SHAPE_GET_CLASS(o) (G_TYPE_INSTANCE_GET_CLASS ((o), OTTIE_TYPE_GROUP_SHAPE, OttieGroupShapeClass))
+
+typedef struct _OttieGroupShape OttieGroupShape;
+typedef struct _OttieGroupShapeClass OttieGroupShapeClass;
+
+GType                   ottie_group_shape_get_type              (void) G_GNUC_CONST;
+
+OttieShape *            ottie_group_shape_new                   (void);
+
+OttieShape *            ottie_group_shape_parse                 (JsonReader             *reader);
+gboolean                ottie_group_shape_parse_shapes          (JsonReader             *reader,
+                                                                 gsize                   offset,
+                                                                 gpointer                data);
+
+G_END_DECLS
+
+#endif /* __OTTIE_GROUP_SHAPE_PRIVATE_H__ */

ottie/ottieintl.h

@@ -0,0 +1,15 @@
+#ifndef __OTTIE_INTL_H__
+#define __OTTIE_INTL_H__
+
+#include <glib/gi18n-lib.h>
+
+#ifdef ENABLE_NLS
+#define P_(String) g_dgettext(GETTEXT_PACKAGE "-properties",String)
+#else 
+#define P_(String) (String)
+#endif
+
+/* not really I18N-related, but also a string marker macro */
+#define I_(string) g_intern_static_string (string)
+
+#endif

ottie/ottiekeyframesimpl.c

@@ -0,0 +1,382 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#include <glib.h>
+
+G_BEGIN_DECLS
+
+#ifndef OTTIE_KEYFRAMES_TYPE_NAME
+#define OTTIE_KEYFRAMES_TYPE_NAME OttieKeyframes
+#endif
+
+#ifndef OTTIE_KEYFRAMES_NAME
+#define OTTIE_KEYFRAMES_NAME ottie_keyframes
+#endif
+
+#ifndef OTTIE_KEYFRAMES_ELEMENT_TYPE
+#define OTTIE_KEYFRAMES_ELEMENT_TYPE gpointer
+#endif
+
+#ifndef OTTIE_KEYFRAMES_DIMENSIONS
+#define OTTIE_KEYFRAMES_DIMENSIONS 1
+#endif
+
+/* make this readable */
+#define _T_ OTTIE_KEYFRAMES_ELEMENT_TYPE
+#define OttieKeyframes OTTIE_KEYFRAMES_TYPE_NAME
+#define OttieKeyframe OTTIE_KEYFRAMES_TYPE_NAME ## Keyframe
+#define OttieControlPoint OTTIE_KEYFRAMES_TYPE_NAME ## ControlPoint
+#define ottie_keyframes_paste_more(OTTIE_KEYFRAMES_NAME, func_name) OTTIE_KEYFRAMES_NAME ## _ ## func_name
+#define ottie_keyframes_paste(OTTIE_KEYFRAMES_NAME, func_name) ottie_keyframes_paste_more (OTTIE_KEYFRAMES_NAME, func_name)
+#define ottie_keyframes(func_name) ottie_keyframes_paste (OTTIE_KEYFRAMES_NAME, func_name)
+
+typedef struct OttieControlPoint OttieControlPoint;
+typedef struct OttieKeyframe OttieKeyframe;
+typedef struct OttieKeyframes OttieKeyframes;
+
+struct OttieControlPoint
+{
+  double x[OTTIE_KEYFRAMES_DIMENSIONS];
+  double y[OTTIE_KEYFRAMES_DIMENSIONS];
+};
+
+struct OttieKeyframe
+{
+  /* Cubic control points, but Lottie names them in and out points */
+  OttieControlPoint in;
+  OttieControlPoint out;
+  double start_time;
+  _T_ start_value;
+  _T_ end_value;
+};
+
+struct OttieKeyframes
+{
+  gsize n_items;
+  OttieKeyframe items[];
+};
+
+static inline OttieKeyframes *
+ottie_keyframes(new) (gsize n_items)
+{
+  OttieKeyframes *self;
+
+  self = g_malloc0 (sizeof (OttieKeyframes) + n_items * sizeof (OttieKeyframe));
+  self->n_items = n_items;
+
+  return self;
+}
+
+static inline void
+ottie_keyframes(free_value) (_T_ *item)
+{
+#ifdef OTTIE_KEYFRAMES_FREE_FUNC
+#ifdef OTTIE_KEYFRAMES_BY_VALUE
+    OTTIE_KEYFRAMES_FREE_FUNC (item);
+#else
+    OTTIE_KEYFRAMES_FREE_FUNC (*item);
+#endif
+#endif
+}
+
+static inline void
+ottie_keyframes(copy_value) (_T_ *dest,
+                             _T_ *src)
+{
+#ifdef OTTIE_KEYFRAMES_COPY_FUNC
+#  ifdef OTTIE_KEYFRAMES_BY_VALUE
+  OTTIE_KEYFRAMES_COPY_FUNC (dest, src);
+#  else
+  *dest = OTTIE_KEYFRAMES_COPY_FUNC (*src);
+#  endif
+#else
+    *dest = *src;
+#endif
+}
+
+/* no G_GNUC_UNUSED here */
+static inline void
+ottie_keyframes(free) (OttieKeyframes *self)
+{
+#ifdef OTTIE_KEYFRAMES_FREE_FUNC
+  gsize i;
+
+  for (i = 0; i < self->n_items; i++)
+    {
+      ottie_keyframes(free_value) (&self->items[i].start_value);
+      ottie_keyframes(free_value) (&self->items[i].end_value);
+    }
+#endif
+}
+
+static
+#ifdef OTTIE_KEYFRAMES_BY_VALUE
+void
+#else
+_T_
+#endif
+ottie_keyframes(get) (const OttieKeyframes *self,
+                      double                timestamp
+#ifdef OTTIE_KEYFRAMES_BY_VALUE
+                      , _T_                *out_result
+#endif
+                      )
+{
+  const OttieKeyframe *keyframe;
+  gsize i;
+
+  for (i = 0; i < self->n_items; i++)
+    {
+      if (self->items[i].start_time > timestamp)
+        break;
+    }
+
+  if (i == 0 || i >= self->n_items)
+    {
+      keyframe = &self->items[i == 0 ? 0 : self->n_items - 1];
+#ifdef OTTIE_KEYFRAMES_BY_VALUE
+      *out_result = keyframe->start_value;
+      return;
+#else
+      return keyframe->start_value;
+#endif
+    }
+
+  keyframe = &self->items[i - 1];
+
+  double progress = (timestamp - keyframe->start_time) / (self->items[i].start_time - keyframe->start_time);
+#ifdef OTTIE_KEYFRAMES_BY_VALUE
+  OTTIE_KEYFRAMES_INTERPOLATE_FUNC (&keyframe->start_value, &keyframe->end_value, progress, out_result);
+#else
+  return OTTIE_KEYFRAMES_INTERPOLATE_FUNC (keyframe->start_value, keyframe->end_value, progress);
+#endif
+}
+
+static gboolean
+ottie_keyframes(parse_control_point_dimension) (JsonReader *reader,
+                                                gsize       offset,
+                                                gpointer    data)
+{
+  double d[OTTIE_KEYFRAMES_DIMENSIONS];
+
+  if (json_reader_is_array (reader))
+    {
+      if (json_reader_count_elements (reader) != OTTIE_KEYFRAMES_DIMENSIONS)
+        ottie_parser_error_value (reader, "control point has %d dimension, not %u", json_reader_count_elements (reader), OTTIE_KEYFRAMES_DIMENSIONS);
+
+      for (int i = 0; i < OTTIE_KEYFRAMES_DIMENSIONS; i++)
+        {
+          if (!json_reader_read_element (reader, i))
+            {
+              ottie_parser_emit_error (reader, json_reader_get_error (reader));
+            }
+          else
+            {
+              if (!ottie_parser_option_double (reader, 0, &d[i]))
+                d[i] = 0;
+            }
+          json_reader_end_element (reader);
+        }
+    }
+  else
+    {
+      if (!ottie_parser_option_double (reader, 0, &d[0]))
+        return FALSE;
+
+      for (gsize i = 1; i < OTTIE_KEYFRAMES_DIMENSIONS; i++)
+        d[i] = d[0];
+    }
+
+  memcpy ((guint8 *) data + GPOINTER_TO_SIZE (offset), d, sizeof (double) * OTTIE_KEYFRAMES_DIMENSIONS);
+  return TRUE;
+}
+
+static gboolean
+ottie_keyframes(parse_control_point) (JsonReader *reader,
+                                      gsize       offset,
+                                      gpointer    data)
+{
+  OttieParserOption options[] = {
+    { "x", ottie_keyframes(parse_control_point_dimension), G_STRUCT_OFFSET (OttieControlPoint, x) },
+    { "y", ottie_keyframes(parse_control_point_dimension), G_STRUCT_OFFSET (OttieControlPoint, y) },
+  };
+  OttieControlPoint cp;
+  OttieControlPoint *target = (OttieControlPoint *) ((guint8 *) data + offset);
+
+  if (!ottie_parser_parse_object (reader, "control point", options, G_N_ELEMENTS (options), &cp))
+    return FALSE;
+
+  *target = cp;
+  return TRUE;
+}
+
+typedef struct
+{
+  OttieKeyframe keyframe;
+  gboolean has_start_value;
+  gboolean has_end_value;
+} OttieKeyframeParse;
+
+static gboolean
+ottie_keyframes(parse_start_value) (JsonReader *reader,
+                                    gsize       pos,
+                                    gpointer    data)
+{
+  OttieKeyframeParse *parse = data;
+
+  if (parse->has_start_value)
+    ottie_keyframes(free_value) (&parse->keyframe.start_value);
+
+  parse->has_start_value = OTTIE_KEYFRAMES_PARSE_FUNC (reader, 0, &parse->keyframe.start_value);
+  return parse->has_start_value;
+}
+
+static gboolean
+ottie_keyframes(parse_end_value) (JsonReader *reader,
+                                  gsize       pos,
+                                  gpointer    data)
+{
+  OttieKeyframeParse *parse = data;
+
+  if (parse->has_end_value)
+    ottie_keyframes(free_value) (&parse->keyframe.end_value);
+
+  parse->has_end_value = OTTIE_KEYFRAMES_PARSE_FUNC (reader, 0, &parse->keyframe.end_value);
+  return parse->has_end_value;
+}
+
+typedef struct
+{
+  OttieKeyframes *keyframes;
+  gboolean has_end_value;
+} OttieKeyframesParse;
+
+static gboolean
+ottie_keyframes(parse_keyframe) (JsonReader *reader,
+                                 gsize       pos,
+                                 gpointer    data)
+{
+  OttieParserOption options[] = {
+    { "s", ottie_keyframes(parse_start_value), 0, },
+    { "e", ottie_keyframes(parse_end_value), 0, },
+    { "t", ottie_parser_option_double, G_STRUCT_OFFSET (OttieKeyframe, start_time) },
+    { "i", ottie_keyframes(parse_control_point), G_STRUCT_OFFSET (OttieKeyframe, in) },
+    { "o", ottie_keyframes(parse_control_point), G_STRUCT_OFFSET (OttieKeyframe, out) },
+    { "ix", ottie_parser_option_skip_index, 0 },
+  };
+  OttieKeyframesParse *self = data;
+  OttieKeyframeParse parse = { 0, };
+
+  if (!ottie_parser_parse_object (reader, "keyframe", options, G_N_ELEMENTS (options), &parse))
+    goto fail;
+
+  if (pos == 0)
+    {
+      if (!parse.has_start_value)
+        {
+          ottie_parser_error_syntax (reader, "First keyframe must have a start value");
+          return FALSE;
+        }
+    }
+  else
+    {
+      if (parse.keyframe.start_time <= self->keyframes->items[pos - 1].start_time)
+        goto fail;
+
+      if (!parse.has_start_value)
+        {
+          if (self->has_end_value)
+            {
+              ottie_keyframes(copy_value) (&parse.keyframe.start_value, &self->keyframes->items[pos - 1].end_value);
+            }
+          else
+            {
+              ottie_parser_error_syntax (reader, "Keyframe %zu has no end value and %zu has no start value.", pos - 1, pos);
+              goto fail;
+            }
+        }
+
+      if (!self->has_end_value)
+        ottie_keyframes(copy_value) (&self->keyframes->items[pos - 1].end_value, &parse.keyframe.start_value);
+    }
+
+  self->has_end_value = parse.has_end_value;
+  self->keyframes->items[pos] = parse.keyframe;
+
+  return TRUE;
+
+fail:
+  self->keyframes->n_items = pos;
+  if (parse.has_start_value)
+    ottie_keyframes(free_value) (&parse.keyframe.start_value);
+  if (parse.has_end_value)
+    ottie_keyframes(free_value) (&parse.keyframe.end_value);
+  return FALSE;
+}
+
+/* no G_GNUC_UNUSED here, if you don't use a type, remove it. */
+static inline OttieKeyframes *
+ottie_keyframes(parse) (JsonReader *reader)
+{
+  OttieKeyframesParse parse;
+  OttieKeyframes *self;
+
+  self = ottie_keyframes(new) (json_reader_count_elements (reader));
+
+  parse.keyframes = self;
+  parse.has_end_value = FALSE;
+
+  if (!ottie_parser_parse_array (reader, "keyframes",
+                                 self->n_items, self->n_items,
+                                 NULL,
+                                 0, 1,
+                                 ottie_keyframes(parse_keyframe),
+                                 &parse))
+    {
+      /* do a dumb copy so the free has something to free */
+      if (!parse.has_end_value && self->n_items > 0)
+        ottie_keyframes(copy_value) (&self->items[self->n_items - 1].end_value,
+                                     &self->items[self->n_items - 1].start_value);
+      ottie_keyframes(free) (self);
+      return NULL;
+    }
+
+  if (!parse.has_end_value)
+    ottie_keyframes(copy_value) (&self->items[self->n_items - 1].end_value,
+                                 &self->items[self->n_items - 1].start_value);
+
+  return parse.keyframes;
+}
+
+#ifndef OTTIE_KEYFRAMES_NO_UNDEF
+
+#undef _T_
+#undef OttieKeyframes
+#undef ottie_keyframes_paste_more
+#undef ottie_keyframes_paste
+#undef ottie_keyframes
+
+#undef OTTIE_KEYFRAMES_COPY_FUNC
+#undef OTTIE_KEYFRAMES_PARSE_FUNC
+#undef OTTIE_KEYFRAMES_BY_VALUE
+#undef OTTIE_KEYFRAMES_ELEMENT_TYPE
+#undef OTTIE_KEYFRAMES_FREE_FUNC
+#undef OTTIE_KEYFRAMES_NAME
+#undef OTTIE_KEYFRAMES_TYPE_NAME
+#endif

ottie/ottielayer.c

@@ -0,0 +1,96 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#include "config.h"
+
+#include "ottielayerprivate.h"
+
+#include <glib/gi18n-lib.h>
+#include <json-glib/json-glib.h>
+
+G_DEFINE_TYPE (OttieLayer, ottie_layer, OTTIE_TYPE_OBJECT)
+
+static void
+ottie_layer_default_update (OttieLayer *self,
+                            GHashTable *compositions)
+{
+}
+
+static void
+ottie_layer_default_render (OttieLayer  *self,
+                            OttieRender *render,
+                            double       timestamp)
+{
+}
+
+static void
+ottie_layer_dispose (GObject *object)
+{
+  OttieLayer *self = OTTIE_LAYER (object);
+
+  g_clear_object (&self->transform);
+  g_clear_pointer (&self->layer_name, g_free);
+
+  G_OBJECT_CLASS (ottie_layer_parent_class)->dispose (object);
+}
+
+static void
+ottie_layer_class_init (OttieLayerClass *klass)
+{
+  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
+
+  klass->update = ottie_layer_default_update;
+  klass->render = ottie_layer_default_render;
+
+  gobject_class->dispose = ottie_layer_dispose;
+}
+
+static void
+ottie_layer_init (OttieLayer *self)
+{
+  self->start_frame = -G_MAXDOUBLE;
+  self->end_frame = G_MAXDOUBLE;
+  self->stretch = 1;
+  self->blend_mode = GSK_BLEND_MODE_DEFAULT;
+  self->parent_index = OTTIE_INT_UNSET;
+  self->index = OTTIE_INT_UNSET;
+}
+
+void
+ottie_layer_update (OttieLayer *self,
+                    GHashTable *compositions)
+{
+  OTTIE_LAYER_GET_CLASS (self)->update (self, compositions);
+}
+
+void
+ottie_layer_render (OttieLayer  *self,
+                    OttieRender *render,
+                    double       timestamp)
+{
+  if (timestamp < self->start_frame ||
+      timestamp > self->end_frame)
+    return;
+
+  timestamp -= self->start_time;
+  timestamp /= self->stretch;
+
+  OTTIE_LAYER_GET_CLASS (self)->render (self, render, timestamp);
+}
+

ottie/ottielayerprivate.h

@@ -0,0 +1,93 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#ifndef __OTTIE_LAYER_PRIVATE_H__
+#define __OTTIE_LAYER_PRIVATE_H__
+
+#include "ottie/ottietransformprivate.h"
+#include "ottie/ottieobjectprivate.h"
+#include "ottie/ottieparserprivate.h"
+#include "ottie/ottierenderprivate.h"
+
+G_BEGIN_DECLS
+
+#define OTTIE_TYPE_LAYER         (ottie_layer_get_type ())
+#define OTTIE_LAYER(o)           (G_TYPE_CHECK_INSTANCE_CAST ((o), OTTIE_TYPE_LAYER, OttieLayer))
+#define OTTIE_LAYER_CLASS(k)     (G_TYPE_CHECK_CLASS_CAST ((k), OTTIE_TYPE_LAYER, OttieLayerClass))
+#define OTTIE_IS_LAYER(o)        (G_TYPE_CHECK_INSTANCE_TYPE ((o), OTTIE_TYPE_LAYER))
+#define OTTIE_IS_LAYER_CLASS(k)  (G_TYPE_CHECK_CLASS_TYPE ((k), OTTIE_TYPE_LAYER))
+#define OTTIE_LAYER_GET_CLASS(o) (G_TYPE_INSTANCE_GET_CLASS ((o), OTTIE_TYPE_LAYER, OttieLayerClass))
+
+typedef struct _OttieLayer OttieLayer;
+typedef struct _OttieLayerClass OttieLayerClass;
+
+struct _OttieLayer
+{
+  OttieObject parent;
+
+  OttieTransform *transform;
+  gboolean auto_orient;
+  GskBlendMode blend_mode;
+  int index;
+  int parent_index;
+  char *layer_name;
+  double start_frame;
+  double end_frame;
+  double start_time;
+  double stretch;
+};
+
+struct _OttieLayerClass
+{
+  OttieObjectClass parent_class;
+
+  void                  (* update)                           (OttieLayer                *layer,
+                                                              GHashTable                *compositions);
+  void                  (* render)                           (OttieLayer                *layer,
+                                                              OttieRender               *render,
+                                                              double                     timestamp);
+};
+
+GType                   ottie_layer_get_type                 (void) G_GNUC_CONST;
+
+void                    ottie_layer_update                   (OttieLayer                *self,
+                                                              GHashTable                *compositions);
+void                    ottie_layer_render                   (OttieLayer                *self,
+                                                              OttieRender               *render,
+                                                              double                     timestamp);
+
+#define OTTIE_PARSE_OPTIONS_LAYER \
+    OTTIE_PARSE_OPTIONS_OBJECT, \
+    { "ao", ottie_parser_option_boolean, G_STRUCT_OFFSET (OttieLayer, auto_orient) }, \
+    { "bm", ottie_parser_option_blend_mode, G_STRUCT_OFFSET (OttieLayer, blend_mode) }, \
+    { "ln", ottie_parser_option_string, G_STRUCT_OFFSET (OttieLayer, layer_name) }, \
+    { "ks", ottie_parser_option_transform, G_STRUCT_OFFSET (OttieLayer, transform) }, \
+    { "ip", ottie_parser_option_double, G_STRUCT_OFFSET (OttieLayer, start_frame) }, \
+    { "ind", ottie_parser_option_int, G_STRUCT_OFFSET (OttieLayer, index) }, \
+    { "parent", ottie_parser_option_int, G_STRUCT_OFFSET (OttieLayer, parent_index) }, \
+    { "op", ottie_parser_option_double, G_STRUCT_OFFSET (OttieLayer, end_frame) }, \
+    { "st", ottie_parser_option_double, G_STRUCT_OFFSET (OttieLayer, start_time) }, \
+    { "sr", ottie_parser_option_double, G_STRUCT_OFFSET (OttieLayer, stretch) }, \
+    { "ddd", ottie_parser_option_3d, 0 }, \
+    { "ix",  ottie_parser_option_skip_index, 0 }, \
+    { "ty", ottie_parser_option_skip, 0 }
+
+G_END_DECLS
+
+#endif /* __OTTIE_LAYER_PRIVATE_H__ */

ottie/ottienulllayer.c

@@ -0,0 +1,66 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#include "config.h"
+
+#include "ottienulllayerprivate.h"
+
+#include <glib/gi18n-lib.h>
+
+struct _OttieNullLayer
+{
+  OttieLayer parent;
+};
+
+struct _OttieNullLayerClass
+{
+  OttieLayerClass parent_class;
+};
+
+G_DEFINE_TYPE (OttieNullLayer, ottie_null_layer, OTTIE_TYPE_LAYER)
+
+static void
+ottie_null_layer_class_init (OttieNullLayerClass *klass)
+{
+}
+
+static void
+ottie_null_layer_init (OttieNullLayer *self)
+{
+}
+
+OttieLayer *
+ottie_null_layer_parse (JsonReader *reader)
+{
+  OttieParserOption options[] = {
+    OTTIE_PARSE_OPTIONS_LAYER,
+  };
+  OttieNullLayer *self;
+
+  self = g_object_new (OTTIE_TYPE_NULL_LAYER, NULL);
+
+  if (!ottie_parser_parse_object (reader, "null layer", options, G_N_ELEMENTS (options), self))
+    {
+      g_object_unref (self);
+      return NULL;
+    }
+
+  return OTTIE_LAYER (self);
+}
+

ottie/ottienulllayerprivate.h

@@ -0,0 +1,45 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#ifndef __OTTIE_NULL_LAYER_PRIVATE_H__
+#define __OTTIE_NULL_LAYER_PRIVATE_H__
+
+#include "ottielayerprivate.h"
+
+#include <json-glib/json-glib.h>
+
+G_BEGIN_DECLS
+
+#define OTTIE_TYPE_NULL_LAYER         (ottie_null_layer_get_type ())
+#define OTTIE_NULL_LAYER(o)           (G_TYPE_CHECK_INSTANCE_CAST ((o), OTTIE_TYPE_NULL_LAYER, OttieNullLayer))
+#define OTTIE_NULL_LAYER_CLASS(k)     (G_TYPE_CHECK_CLASS_CAST ((k), OTTIE_TYPE_NULL_LAYER, OttieNullLayerClass))
+#define OTTIE_IS_NULL_LAYER(o)        (G_TYPE_CHECK_INSTANCE_TYPE ((o), OTTIE_TYPE_NULL_LAYER))
+#define OTTIE_IS_NULL_LAYER_CLASS(k)  (G_TYPE_CHECK_CLASS_TYPE ((k), OTTIE_TYPE_NULL_LAYER))
+#define OTTIE_NULL_LAYER_GET_CLASS(o) (G_TYPE_INSTANCE_GET_CLASS ((o), OTTIE_TYPE_NULL_LAYER, OttieNullLayerClass))
+
+typedef struct _OttieNullLayer OttieNullLayer;
+typedef struct _OttieNullLayerClass OttieNullLayerClass;
+
+GType                   ottie_null_layer_get_type               (void) G_GNUC_CONST;
+
+OttieLayer *            ottie_null_layer_parse                  (JsonReader             *reader);
+
+G_END_DECLS
+
+#endif /* __OTTIE_NULL_LAYER_PRIVATE_H__ */

ottie/ottieobject.c

@@ -0,0 +1,175 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#include "config.h"
+
+#include "ottieobjectprivate.h"
+
+#include "ottieintl.h"
+
+enum {
+  PROP_0,
+  PROP_MATCH_NAME,
+  PROP_NAME,
+
+  N_PROPS,
+};
+
+static GParamSpec *properties[N_PROPS] = { NULL, };
+
+G_DEFINE_TYPE (OttieObject, ottie_object, G_TYPE_OBJECT)
+
+static void
+ottie_object_set_property (GObject      *object,
+                           guint         prop_id,
+                           const GValue *value,
+                           GParamSpec   *pspec)
+
+{
+  OttieObject *self = OTTIE_OBJECT (object);
+
+  switch (prop_id)
+    {
+    case PROP_MATCH_NAME:
+      ottie_object_set_match_name (self, g_value_get_string (value));
+      break;
+
+    case PROP_NAME:
+      ottie_object_set_name (self, g_value_get_string (value));
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void
+ottie_object_get_property (GObject    *object,
+                               guint       prop_id,
+                               GValue     *value,
+                               GParamSpec *pspec)
+{
+  OttieObject *self = OTTIE_OBJECT (object);
+
+  switch (prop_id)
+    {
+    case PROP_MATCH_NAME:
+      g_value_set_string (value, self->match_name);
+      break;
+
+    case PROP_NAME:
+      g_value_set_string (value, self->name);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void
+ottie_object_dispose (GObject *object)
+{
+  OttieObject *self = OTTIE_OBJECT (object);
+
+  g_clear_pointer (&self->name, g_free);
+  g_clear_pointer (&self->match_name, g_free);
+
+  G_OBJECT_CLASS (ottie_object_parent_class)->dispose (object);
+}
+
+static void
+ottie_object_class_init (OttieObjectClass *class)
+{
+  GObjectClass *gobject_class = G_OBJECT_CLASS (class);
+
+  gobject_class->set_property = ottie_object_set_property;
+  gobject_class->get_property = ottie_object_get_property;
+  gobject_class->dispose = ottie_object_dispose;
+
+  properties[PROP_NAME] =
+    g_param_spec_string ("name",
+                         P_("Name"),
+                         P_("User-given name"),
+                         NULL,
+                         G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
+  properties[PROP_MATCH_NAME] =
+    g_param_spec_string ("match-name",
+                         P_("Match name"),
+                         P_("Name for matching in scripts"),
+                         NULL,
+                         G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
+  g_object_class_install_properties (gobject_class, N_PROPS, properties);
+}
+
+static void
+ottie_object_init (OttieObject *self)
+{
+}
+
+void
+ottie_object_set_name (OttieObject *self,
+                       const char  *name)
+{
+  g_return_if_fail (OTTIE_IS_OBJECT (self));
+
+  if (g_strcmp0 (self->name, name) == 0)
+    return;
+
+  g_free (self->name);
+  self->name = g_strdup (name);
+
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_NAME]);
+}
+
+const char *
+ottie_object_get_name (OttieObject *self)
+{
+  g_return_val_if_fail (OTTIE_IS_OBJECT (self), NULL);
+
+  return self->name;
+}
+
+void
+ottie_object_set_match_name (OttieObject *self,
+                             const char  *match_name)
+{
+  g_return_if_fail (OTTIE_IS_OBJECT (self));
+
+  if (g_strcmp0 (self->match_name, match_name) == 0)
+    return;
+
+  g_free (self->match_name);
+  self->match_name = g_strdup (match_name);
+
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_MATCH_NAME]);
+}
+
+const char *
+ottie_object_get_match_name (OttieObject *self)
+{
+  g_return_val_if_fail (OTTIE_IS_OBJECT (self), NULL);
+
+  return self->match_name;
+}
+
+

ottie/ottieobjectprivate.h

@@ -0,0 +1,68 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#ifndef __OTTIE_OBJECT_PRIVATE_H__
+#define __OTTIE_OBJECT_PRIVATE_H__
+
+#include <glib-object.h>
+
+#include "ottie/ottierenderprivate.h"
+
+G_BEGIN_DECLS
+
+#define OTTIE_TYPE_OBJECT         (ottie_object_get_type ())
+#define OTTIE_OBJECT(o)           (G_TYPE_CHECK_INSTANCE_CAST ((o), OTTIE_TYPE_OBJECT, OttieObject))
+#define OTTIE_OBJECT_CLASS(k)     (G_TYPE_CHECK_CLASS_CAST ((k), OTTIE_TYPE_OBJECT, OttieObjectClass))
+#define OTTIE_IS_OBJECT(o)        (G_TYPE_CHECK_INSTANCE_TYPE ((o), OTTIE_TYPE_OBJECT))
+#define OTTIE_IS_OBJECT_CLASS(k)  (G_TYPE_CHECK_CLASS_TYPE ((k), OTTIE_TYPE_OBJECT))
+#define OTTIE_OBJECT_GET_CLASS(o) (G_TYPE_INSTANCE_GET_CLASS ((o), OTTIE_TYPE_OBJECT, OttieObjectClass))
+
+typedef struct _OttieObject OttieObject;
+typedef struct _OttieObjectClass OttieObjectClass;
+
+struct _OttieObject
+{
+  GObject parent;
+
+  char *name;
+  char *match_name;
+};
+
+struct _OttieObjectClass
+{
+  GObjectClass parent_class;
+};
+
+GType                   ottie_object_get_type                   (void) G_GNUC_CONST;
+
+void                    ottie_object_set_name                   (OttieObject            *self,
+                                                                 const char             *name);
+const char *            ottie_object_get_name                   (OttieObject            *self);
+
+void                    ottie_object_set_match_name             (OttieObject            *self,
+                                                                 const char             *match_name);
+const char *            ottie_object_get_match_name             (OttieObject            *self);
+
+#define OTTIE_PARSE_OPTIONS_OBJECT \
+    { "nm", ottie_parser_option_string, G_STRUCT_OFFSET (OttieObject, name) }, \
+    { "mn", ottie_parser_option_string, G_STRUCT_OFFSET (OttieObject, match_name) }
+
+G_END_DECLS
+
+#endif /* __OTTIE_OBJECT_PRIVATE_H__ */

ottie/ottiepaintable.c

@@ -0,0 +1,381 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#include "config.h"
+
+#include "ottiepaintable.h"
+
+#include "ottiecreationprivate.h"
+
+#include <math.h>
+#include <glib/gi18n.h>
+
+struct _OttiePaintable
+{
+  GObject parent_instance;
+
+  OttieCreation *creation;
+  gint64 timestamp;
+};
+
+struct _OttiePaintableClass
+{
+  GObjectClass parent_class;
+};
+
+enum {
+  PROP_0,
+  PROP_CREATION,
+  PROP_DURATION,
+  PROP_TIMESTAMP,
+
+  N_PROPS,
+};
+
+static GParamSpec *properties[N_PROPS] = { NULL, };
+
+static void
+ottie_paintable_paintable_snapshot (GdkPaintable *paintable,
+                                    GdkSnapshot  *snapshot,
+                                    double        width,
+                                    double        height)
+{
+  OttiePaintable *self = OTTIE_PAINTABLE (paintable);
+  double w, h, timestamp;
+
+  if (!self->creation)
+    return;
+
+  w = ottie_creation_get_width (self->creation);
+  h = ottie_creation_get_height (self->creation);
+  timestamp = (double) self->timestamp / G_USEC_PER_SEC;
+
+  if (w != width || h != height)
+    {
+      gtk_snapshot_save (snapshot);
+      gtk_snapshot_scale (snapshot, width / w, height / h);
+    }
+
+  gtk_snapshot_push_clip (snapshot, &GRAPHENE_RECT_INIT (0, 0, w, h));
+  ottie_creation_snapshot (self->creation, snapshot, timestamp);
+  gtk_snapshot_pop (snapshot);
+
+  if (w != width || h != height)
+    gtk_snapshot_restore (snapshot);
+}
+
+static int
+ottie_paintable_paintable_get_intrinsic_width (GdkPaintable *paintable)
+{
+  OttiePaintable *self = OTTIE_PAINTABLE (paintable);
+
+  if (!self->creation)
+    return 0;
+
+  return ceil (ottie_creation_get_width (self->creation));
+}
+
+static int
+ottie_paintable_paintable_get_intrinsic_height (GdkPaintable *paintable)
+{
+  OttiePaintable *self = OTTIE_PAINTABLE (paintable);
+
+  if (!self->creation)
+    return 0;
+
+  return ceil (ottie_creation_get_height (self->creation));
+
+}
+
+static void
+ottie_paintable_paintable_init (GdkPaintableInterface *iface)
+{
+  iface->snapshot = ottie_paintable_paintable_snapshot;
+  iface->get_intrinsic_width = ottie_paintable_paintable_get_intrinsic_width;
+  iface->get_intrinsic_height = ottie_paintable_paintable_get_intrinsic_height;
+}
+
+G_DEFINE_TYPE_EXTENDED (OttiePaintable, ottie_paintable, G_TYPE_OBJECT, 0,
+                        G_IMPLEMENT_INTERFACE (GDK_TYPE_PAINTABLE,
+                                               ottie_paintable_paintable_init))
+
+static void
+ottie_paintable_set_property (GObject      *object,
+                              guint         prop_id,
+                              const GValue *value,
+                              GParamSpec   *pspec)
+
+{
+  OttiePaintable *self = OTTIE_PAINTABLE (object);
+
+  switch (prop_id)
+    {
+    case PROP_CREATION:
+      ottie_paintable_set_creation (self, g_value_get_object (value));
+      break;
+
+    case PROP_TIMESTAMP:
+      ottie_paintable_set_timestamp (self, g_value_get_int64 (value));
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void
+ottie_paintable_get_property (GObject    *object,
+                              guint       prop_id,
+                              GValue     *value,
+                              GParamSpec *pspec)
+{
+  OttiePaintable *self = OTTIE_PAINTABLE (object);
+
+  switch (prop_id)
+    {
+    case PROP_CREATION:
+      g_value_set_object (value, self->creation);
+      break;
+
+    case PROP_DURATION:
+      g_value_set_int64 (value, ottie_paintable_get_duration (self));
+      break;
+
+    case PROP_TIMESTAMP:
+      g_value_set_int64 (value, self->timestamp);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void
+ottie_paintable_prepared_cb (OttieCreation  *creation,
+                             GParamSpec     *pspec,
+                             OttiePaintable *self)
+{
+  gdk_paintable_invalidate_size (GDK_PAINTABLE (self));
+  gdk_paintable_invalidate_contents (GDK_PAINTABLE (self));
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_DURATION]);
+}
+
+static void
+ottie_paintable_unset_creation (OttiePaintable *self)
+{
+  if (self->creation == NULL)
+    return;
+
+  g_signal_handlers_disconnect_by_func (self->creation, ottie_paintable_prepared_cb, self);
+  g_clear_object (&self->creation);
+}
+
+static void
+ottie_paintable_dispose (GObject *object)
+{
+  OttiePaintable *self = OTTIE_PAINTABLE (object);
+
+  ottie_paintable_unset_creation (self);
+
+  G_OBJECT_CLASS (ottie_paintable_parent_class)->dispose (object);
+}
+
+static void
+ottie_paintable_class_init (OttiePaintableClass *klass)
+{
+  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
+
+  gobject_class->get_property = ottie_paintable_get_property;
+  gobject_class->set_property = ottie_paintable_set_property;
+  gobject_class->dispose = ottie_paintable_dispose;
+
+  /**
+   * OttiePaintable:creation
+   *
+   * The displayed creation or %NULL.
+   */
+  properties[PROP_CREATION] =
+    g_param_spec_object ("creation",
+                         _("Creation"),
+                         _("The displayed creation"),
+                         OTTIE_TYPE_CREATION,
+                         G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
+  /**
+   * OttiePaintable:duration
+   *
+   * Duration of the displayed creation
+   */
+  properties[PROP_DURATION] =
+    g_param_spec_int64 ("duration",
+                        _("Duration"),
+                        _("Duration of the displayed creation"),
+                        0, G_MAXINT64, 0,
+                        G_PARAM_READABLE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
+  /**
+   * OttiePaintable:timestamp
+   *
+   * At what timestamp to display the creation.
+   */
+  properties[PROP_TIMESTAMP] =
+    g_param_spec_int64 ("timestmp",
+                        _("Timestamp"),
+                        _("At what timestamp to display the creation"),
+                        0, G_MAXINT64, 0,
+                        G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
+  g_object_class_install_properties (gobject_class, N_PROPS, properties);
+}
+
+static void
+ottie_paintable_init (OttiePaintable *self)
+{
+}
+
+/**
+ * ottie_paintable_new:
+ * @creation: (allow-none) (transfer full): an #OttiePaintable or %NULL
+ *
+ * Creates a new Ottie paintable for the given @creation
+ *
+ * Returns: (transfer full) (type OttiePaintable): a new #OttiePaintable
+ **/
+OttiePaintable *
+ottie_paintable_new (OttieCreation *creation)
+{
+  OttiePaintable *self;
+
+  g_return_val_if_fail (creation == creation || OTTIE_IS_CREATION (creation), NULL);
+
+  self = g_object_new (OTTIE_TYPE_PAINTABLE,
+                       "creation", creation,
+                       NULL);
+
+  g_clear_object (&creation);
+
+  return self;
+}
+
+/**
+ * ottie_paintable_get_creation:
+ * @self: an #OttiePaintable
+ *
+ * Returns the creation that shown or %NULL
+ * if none.
+ *
+ * Returns: (transfer none) (nullable): the observed creation.
+ **/
+OttieCreation *
+ottie_paintable_get_creation (OttiePaintable *self)
+{
+  g_return_val_if_fail (OTTIE_IS_PAINTABLE (self), NULL);
+
+  return self->creation;
+}
+
+/**
+ * ottie_paintable_set_creation:
+ * @self: an #OttiePaintable
+ * @creation: (allow-none): the creation to show or %NULL
+ *
+ * Sets the creation that should be shown.
+ **/
+void
+ottie_paintable_set_creation (OttiePaintable *self,
+                              OttieCreation  *creation)
+{
+  g_return_if_fail (OTTIE_IS_PAINTABLE (self));
+  g_return_if_fail (creation == NULL || OTTIE_IS_CREATION (creation));
+
+  if (self->creation == creation)
+    return;
+
+  ottie_paintable_unset_creation (self);
+
+  self->creation = g_object_ref (creation);
+  g_signal_connect (creation, "notify::prepared", G_CALLBACK (ottie_paintable_prepared_cb), self);
+
+  gdk_paintable_invalidate_size (GDK_PAINTABLE (self));
+  gdk_paintable_invalidate_contents (GDK_PAINTABLE (self));
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_CREATION]);
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_DURATION]);
+}
+
+/**
+ * ottie_paintable_get_timestamp:
+ * @self: an #OttiePaintable
+ *
+ * Gets the timestamp for the currently displayed image. 
+ *
+ * Returns: the timestamp
+ **/
+gint64
+ottie_paintable_get_timestamp (OttiePaintable *self)
+{
+  g_return_val_if_fail (OTTIE_IS_PAINTABLE (self), 0);
+
+  return self->timestamp;
+}
+
+/**
+ * ottie_paintable_set_timestamp:
+ * @self: an #OttiePaintable
+ * @timestamp: the timestamp to display
+ *
+ * Sets the timestamp to display the creation at.
+ **/
+void
+ottie_paintable_set_timestamp (OttiePaintable *self,
+                               gint64          timestamp)
+{
+  g_return_if_fail (OTTIE_IS_PAINTABLE (self));
+  g_return_if_fail (timestamp >= 0);
+
+  if (self->timestamp == timestamp)
+    return;
+
+  self->timestamp = timestamp;
+
+  gdk_paintable_invalidate_contents (GDK_PAINTABLE (self));
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_TIMESTAMP]);
+}
+
+/**
+ * ottie_paintable_get_duration:
+ * @self: an #OttiePaintable
+ *
+ * Gets the duration of the currently playing creation.
+ *
+ * Returns: The duration in usec.
+ **/
+gint64
+ottie_paintable_get_duration (OttiePaintable *self)
+{
+  g_return_val_if_fail (OTTIE_IS_PAINTABLE (self), 0);
+
+  if (self->creation == NULL)
+    return 0;
+
+  return ceil (G_USEC_PER_SEC * ottie_creation_get_end_frame (self->creation)
+               / ottie_creation_get_frame_rate (self->creation));
+}
+

ottie/ottiepaintable.h

@@ -0,0 +1,54 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#ifndef __OTTIE_PAINTABLE_H__
+#define __OTTIE_PAINTABLE_H__
+
+#if !defined (__OTTIE_H_INSIDE__) && !defined (GTK_COMPILATION)
+#error "Only <ottie/ottie.h> can be included directly."
+#endif
+
+#include <ottie/ottiecreation.h>
+
+G_BEGIN_DECLS
+
+#define OTTIE_TYPE_PAINTABLE (ottie_paintable_get_type ())
+
+GDK_AVAILABLE_IN_ALL
+G_DECLARE_FINAL_TYPE (OttiePaintable, ottie_paintable, OTTIE, PAINTABLE, GObject)
+
+GDK_AVAILABLE_IN_ALL
+OttiePaintable *        ottie_paintable_new                (OttieCreation       *creation);
+
+GDK_AVAILABLE_IN_ALL
+OttieCreation *         ottie_paintable_get_creation       (OttiePaintable      *self);
+GDK_AVAILABLE_IN_ALL
+void                    ottie_paintable_set_creation       (OttiePaintable      *self,
+                                                            OttieCreation       *creation);
+GDK_AVAILABLE_IN_ALL
+gint64                  ottie_paintable_get_timestamp      (OttiePaintable      *self);
+GDK_AVAILABLE_IN_ALL
+void                    ottie_paintable_set_timestamp      (OttiePaintable      *self,
+                                                            gint64               timestamp);
+GDK_AVAILABLE_IN_ALL
+gint64                  ottie_paintable_get_duration       (OttiePaintable      *self);
+
+G_END_DECLS
+
+#endif /* __OTTIE_PAINTABLE_H__ */

ottie/ottieparser.c

@@ -0,0 +1,592 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#include "config.h"
+
+#include "ottieparserprivate.h"
+
+#include "ottietransformprivate.h"
+
+#include <gsk/gsk.h>
+
+void
+ottie_parser_emit_error (JsonReader    *reader,
+                         const GError  *error)
+{
+  g_printerr ("Ottie is sad: %s\n", error->message);
+}
+
+void
+ottie_parser_error_syntax (JsonReader *reader,
+                           const char *format,
+                           ...)
+{
+  va_list args;
+  GError *error;
+
+  va_start (args, format);
+  error = g_error_new_valist (JSON_PARSER_ERROR,
+                              JSON_PARSER_ERROR_INVALID_DATA,
+                              format, args);
+  va_end (args);
+
+  ottie_parser_emit_error (reader, error);
+
+  g_error_free (error);
+}
+
+void
+ottie_parser_error_value (JsonReader *reader,
+                          const char *format,
+                          ...)
+{
+  va_list args;
+  GError *error;
+
+  va_start (args, format);
+  error = g_error_new_valist (JSON_PARSER_ERROR,
+                              JSON_PARSER_ERROR_INVALID_DATA,
+                              format, args);
+  va_end (args);
+
+  ottie_parser_emit_error (reader, error);
+
+  g_error_free (error);
+}
+
+void
+ottie_parser_error_unsupported (JsonReader *reader,
+                                const char *format,
+                                ...)
+{
+  va_list args;
+  GError *error;
+
+  va_start (args, format);
+  error = g_error_new_valist (JSON_PARSER_ERROR,
+                              JSON_PARSER_ERROR_INVALID_DATA,
+                              format, args);
+  va_end (args);
+
+  ottie_parser_emit_error (reader, error);
+
+  g_error_free (error);
+}
+
+gboolean
+ottie_parser_parse_array (JsonReader     *reader,
+                          const char     *debug_name,
+                          guint           min_items,
+                          guint           max_items,
+                          guint          *out_n_items,
+                          gsize           start_offset,
+                          gsize           offset_multiplier,
+                          OttieParseFunc  func,
+                          gpointer        data)
+{
+  guint i;
+
+  if (!json_reader_is_array (reader))
+    {
+      if (min_items > 1)
+        {
+          ottie_parser_error_syntax (reader, "Expected an array when parsing %s", debug_name);
+          if (out_n_items)
+            *out_n_items = 0;
+          return FALSE;
+        }
+      else
+        {
+          if (!func (reader, start_offset, data))
+            {
+              if (out_n_items)
+                *out_n_items = 0;
+              return FALSE;
+            }
+          if (out_n_items)
+            *out_n_items = 1;
+          return TRUE;
+        }
+    }
+
+  if (json_reader_count_elements (reader) < min_items)
+    {
+      ottie_parser_error_syntax (reader, "%s needs %u items, but only %u given",
+                                 debug_name, min_items, json_reader_count_elements (reader));
+      return FALSE;
+    }
+  max_items = MIN (max_items, json_reader_count_elements (reader));
+
+  for (i = 0; i < max_items; i++)
+    {
+      if (!json_reader_read_element (reader, i) || 
+          !func (reader, start_offset + offset_multiplier * i, data))
+        {
+          json_reader_end_element (reader);
+          if (out_n_items)
+            *out_n_items = i;
+          return FALSE;
+        }
+
+      json_reader_end_element (reader);
+    }
+
+  if (out_n_items)
+    *out_n_items = i;
+  return TRUE;
+}
+
+gboolean
+ottie_parser_parse_object (JsonReader              *reader,
+                           const char              *debug_name,
+                           const OttieParserOption *options,
+                           gsize                    n_options,
+                           gpointer                 data)
+{
+  if (!json_reader_is_object (reader))
+    {
+      ottie_parser_error_syntax (reader, "Expected an object when parsing %s", debug_name);
+      return FALSE;
+    }
+
+  for (int i = 0; ; i++)
+    {
+      const OttieParserOption *o = NULL;
+      const char *name;
+
+      if (!json_reader_read_element (reader, i))
+        break;
+
+      name = json_reader_get_member_name (reader);
+
+      for (gsize j = 0; j < n_options; j++)
+        {
+          o = &options[j];
+          if (g_str_equal (o->name, name))
+            break;
+          o = NULL;
+        }
+
+      if (o)
+        {
+          if (!o->parse_func (reader, o->option_data, data))
+            {
+              json_reader_end_element (reader);
+              return FALSE;
+            }
+        }
+      else
+        {
+          ottie_parser_error_unsupported (reader, "Unsupported %s property \"%s\"", debug_name, json_reader_get_member_name (reader));
+        }
+
+      json_reader_end_element (reader);
+    }
+
+  json_reader_end_element (reader);
+
+  return TRUE;
+}
+
+gboolean
+ottie_parser_option_skip (JsonReader *reader,
+                          gsize       offset,
+                          gpointer    data)
+{
+  return TRUE;
+}
+
+gboolean
+ottie_parser_option_boolean (JsonReader *reader,
+                             gsize       offset,
+                             gpointer    data)
+{
+  gboolean b;
+
+  b = json_reader_get_boolean_value (reader);
+  if (json_reader_get_error (reader))
+    {
+      ottie_parser_emit_error (reader, json_reader_get_error (reader));
+      json_reader_end_element (reader);
+      return FALSE;
+    }
+  
+  *(gboolean *) ((guint8 *) data + offset) = b;
+
+  return TRUE;
+}
+
+gboolean
+ottie_parser_option_double (JsonReader *reader,
+                            gsize       offset,
+                            gpointer    data)
+{
+  double d;
+
+  d = json_reader_get_double_value (reader);
+  if (json_reader_get_error (reader))
+    {
+      ottie_parser_emit_error (reader, json_reader_get_error (reader));
+      return FALSE;
+    }
+  
+  *(double *) ((guint8 *) data + offset) = d;
+
+  return TRUE;
+}
+
+gboolean
+ottie_parser_option_int (JsonReader *reader,
+                         gsize       offset,
+                         gpointer    data)
+{
+  gint64 i;
+
+  i = json_reader_get_int_value (reader);
+  if (json_reader_get_error (reader))
+    {
+      ottie_parser_emit_error (reader, json_reader_get_error (reader));
+      return FALSE;
+    }
+  
+  if (i > G_MAXINT || i < G_MININT)
+    {
+      ottie_parser_error_value (reader, "Integer value %"G_GINT64_FORMAT" out of range", i);
+      return FALSE;
+    }
+  if (i == OTTIE_INT_UNSET)
+    {
+      ottie_parser_error_unsupported (reader, "The Integer value %d is a magic internal value of Ottie, file a bug", OTTIE_INT_UNSET);
+      return FALSE;
+    }
+
+  *(int *) ((guint8 *) data + offset) = i;
+
+  return TRUE;
+}
+
+gboolean
+ottie_parser_option_string (JsonReader *reader,
+                            gsize       offset,
+                            gpointer    data)
+{
+  char **target;
+  const char *s;
+
+  s = json_reader_get_string_value (reader);
+  if (json_reader_get_error (reader))
+    {
+      ottie_parser_emit_error (reader, json_reader_get_error (reader));
+      return FALSE;
+    }
+  
+  target = (char **) ((guint8 *) data + offset);
+
+  g_clear_pointer (target, g_free);
+  *target = g_strdup (s);
+
+  return TRUE;
+}
+
+gboolean
+ottie_parser_option_blend_mode (JsonReader *reader,
+                                gsize       offset,
+                                gpointer    data)
+{
+  GskBlendMode blend_mode;
+  gint64 i;
+
+  i = json_reader_get_int_value (reader);
+  if (json_reader_get_error (reader))
+    {
+      ottie_parser_emit_error (reader, json_reader_get_error (reader));
+      return FALSE;
+    }
+  
+  switch (i)
+  {
+    case 0:
+      blend_mode = GSK_BLEND_MODE_DEFAULT;
+      break;
+
+    case 1:
+      blend_mode = GSK_BLEND_MODE_MULTIPLY;
+      break;
+
+    case 2:
+      blend_mode = GSK_BLEND_MODE_SCREEN;
+      break;
+
+    case 3:
+      blend_mode = GSK_BLEND_MODE_OVERLAY;
+      break;
+
+    case 4:
+      blend_mode = GSK_BLEND_MODE_DARKEN;
+      break;
+
+    case 5:
+      blend_mode = GSK_BLEND_MODE_LIGHTEN;
+      break;
+
+    case 6:
+      blend_mode = GSK_BLEND_MODE_COLOR_DODGE;
+      break;
+
+    case 7:
+      blend_mode = GSK_BLEND_MODE_COLOR_BURN;
+      break;
+
+    case 8:
+      blend_mode = GSK_BLEND_MODE_HARD_LIGHT;
+      break;
+
+    case 9:
+      blend_mode = GSK_BLEND_MODE_SOFT_LIGHT;
+      break;
+
+    case 10:
+      blend_mode = GSK_BLEND_MODE_DIFFERENCE;
+      break;
+
+    case 11:
+      blend_mode = GSK_BLEND_MODE_EXCLUSION;
+      break;
+
+    case 12:
+      blend_mode = GSK_BLEND_MODE_HUE;
+      break;
+
+    case 13:
+      blend_mode = GSK_BLEND_MODE_SATURATION;
+      break;
+
+    case 14:
+      blend_mode = GSK_BLEND_MODE_COLOR;
+      break;
+
+    case 15:
+      blend_mode = GSK_BLEND_MODE_LUMINOSITY;
+      break;
+
+    default:
+      ottie_parser_error_value (reader, "%"G_GINT64_FORMAT" is not a known blend mode", i);
+      return FALSE;
+  }
+
+  if (blend_mode != GSK_BLEND_MODE_DEFAULT)
+    ottie_parser_error_value (reader, "Blend modes are not implemented yet.");
+    
+  *(GskBlendMode *) ((guint8 *) data + offset) = blend_mode;
+
+  return TRUE;
+}
+
+gboolean
+ottie_parser_option_3d (JsonReader *reader,
+                        gsize       offset,
+                        gpointer    data)
+{
+  double d;
+
+  d = json_reader_get_double_value (reader);
+  if (json_reader_get_error (reader))
+    {
+      ottie_parser_emit_error (reader, json_reader_get_error (reader));
+      return FALSE;
+    }
+  
+  if (d != 0)
+    {
+      ottie_parser_error_value (reader, "3D is not supported.");
+    }
+
+  return TRUE;
+}
+
+gboolean
+ottie_parser_option_direction (JsonReader *reader,
+                               gsize       offset,
+                               gpointer    data)
+{
+  OttieDirection direction;
+  gint64 i;
+
+  i = json_reader_get_int_value (reader);
+  if (json_reader_get_error (reader))
+    {
+      ottie_parser_emit_error (reader, json_reader_get_error (reader));
+      return FALSE;
+    }
+  
+  switch (i)
+  {
+    default:
+      ottie_parser_error_value (reader, "%"G_GINT64_FORMAT" is not a known direction", i);
+      G_GNUC_FALLTHROUGH;
+    case 0:
+      direction = OTTIE_DIRECTION_FORWARD;
+      break;
+
+    case 1:
+    case 2:
+      direction = OTTIE_DIRECTION_BACKWARD;
+      break;
+  }
+
+  *(OttieDirection *) ((guint8 *) data + offset) = direction;
+
+  return TRUE;
+}
+
+gboolean
+ottie_parser_option_line_cap (JsonReader *reader,
+                              gsize       offset,
+                              gpointer    data)
+{
+  GskLineCap line_cap;
+  gint64 i;
+
+  i = json_reader_get_int_value (reader);
+  if (json_reader_get_error (reader))
+    {
+      ottie_parser_emit_error (reader, json_reader_get_error (reader));
+      return FALSE;
+    }
+  
+  switch (i)
+  {
+    case 1:
+      line_cap = GSK_LINE_CAP_BUTT;
+      break;
+
+    case 2:
+      line_cap = GSK_LINE_CAP_ROUND;
+      break;
+
+    case 3:
+      line_cap = GSK_LINE_CAP_SQUARE;
+      break;
+
+    default:
+      ottie_parser_error_value (reader, "%"G_GINT64_FORMAT" is not a known line cap", i);
+      return FALSE;
+  }
+
+  *(GskLineCap *) ((guint8 *) data + offset) = line_cap;
+
+  return TRUE;
+}
+
+gboolean
+ottie_parser_option_line_join (JsonReader *reader,
+                               gsize       offset,
+                               gpointer    data)
+{
+  GskLineJoin line_join;
+  gint64 i;
+
+  i = json_reader_get_int_value (reader);
+  if (json_reader_get_error (reader))
+    {
+      ottie_parser_emit_error (reader, json_reader_get_error (reader));
+      return FALSE;
+    }
+  
+  switch (i)
+  {
+    case 1:
+      line_join = GSK_LINE_JOIN_MITER;
+      break;
+
+    case 2:
+      line_join = GSK_LINE_JOIN_ROUND;
+      break;
+
+    case 3:
+      line_join = GSK_LINE_JOIN_BEVEL;
+      break;
+
+    default:
+      ottie_parser_error_value (reader, "%"G_GINT64_FORMAT" is not a known line join", i);
+      return FALSE;
+  }
+
+  *(GskLineJoin *) ((guint8 *) data + offset) = line_join;
+
+  return TRUE;
+}
+
+gboolean
+ottie_parser_option_fill_rule (JsonReader *reader,
+                               gsize       offset,
+                               gpointer    data)
+{
+  GskFillRule fill_rule;
+  gint64 i;
+
+  i = json_reader_get_int_value (reader);
+  if (json_reader_get_error (reader))
+    {
+      ottie_parser_emit_error (reader, json_reader_get_error (reader));
+      return FALSE;
+    }
+  
+  switch (i)
+  {
+    case 1:
+      fill_rule = GSK_FILL_RULE_WINDING;
+      break;
+
+    case 2:
+      fill_rule = GSK_FILL_RULE_EVEN_ODD;
+      break;
+
+    default:
+      ottie_parser_error_value (reader, "%"G_GINT64_FORMAT" is not a known fill rule", i);
+      /* XXX: really? */
+      fill_rule = GSK_FILL_RULE_EVEN_ODD;
+      break;
+  }
+
+  *(GskFillRule *) ((guint8 *) data + offset) = fill_rule;
+
+  return TRUE;
+}
+
+gboolean
+ottie_parser_option_transform (JsonReader *reader,
+                               gsize       offset,
+                               gpointer    data)
+{
+  OttieShape **target;
+  OttieShape *t;
+
+  t = ottie_transform_parse (reader);
+  if (t == NULL)
+    return FALSE;
+  
+  target = (OttieShape **) ((guint8 *) data + offset);
+
+  g_clear_object (target);
+  *target = t;
+
+  return TRUE;
+}
+

ottie/ottieparserprivate.h

@@ -0,0 +1,115 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#ifndef __OTTIE_PARSER_PRIVATE_H__
+#define __OTTIE_PARSER_PRIVATE_H__
+
+#include <json-glib/json-glib.h>
+
+G_BEGIN_DECLS
+
+/* for integers where we want to track that nobody has assigned a value to them */
+#define OTTIE_INT_UNSET G_MININT
+
+typedef enum
+{
+  OTTIE_DIRECTION_FORWARD,
+  OTTIE_DIRECTION_BACKWARD
+} OttieDirection;
+
+typedef struct _OttieParserOption OttieParserOption;
+
+typedef gboolean (* OttieParseFunc) (JsonReader *reader, gsize offset, gpointer data);
+
+struct _OttieParserOption
+{
+  const char *name;
+  OttieParseFunc parse_func;
+  gsize option_data;
+};
+
+void                    ottie_parser_emit_error                 (JsonReader             *reader,
+                                                                 const GError           *error);
+void                    ottie_parser_error_syntax               (JsonReader             *reader,
+                                                                 const char             *format,
+                                                                 ...) G_GNUC_PRINTF (2, 3);
+void                    ottie_parser_error_value                (JsonReader             *reader,
+                                                                 const char             *format,
+                                                                 ...) G_GNUC_PRINTF (2, 3);
+void                    ottie_parser_error_unsupported          (JsonReader             *reader,
+                                                                 const char             *format,
+                                                                 ...) G_GNUC_PRINTF (2, 3);
+
+gboolean                ottie_parser_parse_array               (JsonReader              *reader,
+                                                                const char              *debug_name,
+                                                                guint                    min_items,
+                                                                guint                    max_items,
+                                                                guint                   *out_n_items,
+                                                                gsize                    start_offset,
+                                                                gsize                    offset_multiplier,
+                                                                OttieParseFunc           func,
+                                                                gpointer                 data);
+
+gboolean                ottie_parser_parse_object              (JsonReader              *reader,
+                                                                const char              *debug_name,
+                                                                const OttieParserOption *options,
+                                                                gsize                    n_options,
+                                                                gpointer                 data);
+gboolean                ottie_parser_option_skip               (JsonReader              *reader,
+                                                                gsize                    offset,
+                                                                gpointer                 data);
+#define ottie_parser_option_skip_index ottie_parser_option_skip
+#define ottie_parser_option_skip_expression ottie_parser_option_skip
+gboolean                ottie_parser_option_boolean            (JsonReader              *reader,
+                                                                gsize                    offset,
+                                                                gpointer                 data);
+gboolean                ottie_parser_option_int                (JsonReader              *reader,
+                                                                gsize                    offset,
+                                                                gpointer                 data);
+gboolean                ottie_parser_option_double             (JsonReader              *reader,
+                                                                gsize                    offset,
+                                                                gpointer                 data);
+gboolean                ottie_parser_option_string             (JsonReader              *reader,
+                                                                gsize                    offset,
+                                                                gpointer                 data);
+gboolean                ottie_parser_option_3d                 (JsonReader              *reader,
+                                                                gsize                    offset,
+                                                                gpointer                 data);
+gboolean                ottie_parser_option_direction          (JsonReader              *reader,
+                                                                gsize                    offset,
+                                                                gpointer                 data);
+gboolean                ottie_parser_option_blend_mode         (JsonReader              *reader,
+                                                                gsize                    offset,
+                                                                gpointer                 data);
+gboolean                ottie_parser_option_line_cap           (JsonReader              *reader,
+                                                                gsize                    offset,
+                                                                gpointer                 data);
+gboolean                ottie_parser_option_line_join          (JsonReader              *reader,
+                                                                gsize                    offset,
+                                                                gpointer                 data);
+gboolean                ottie_parser_option_fill_rule          (JsonReader              *reader,
+                                                                gsize                    offset,
+                                                                gpointer                 data);
+gboolean                ottie_parser_option_transform          (JsonReader              *reader,
+                                                                gsize                    offset,
+                                                                gpointer                 data);
+
+G_END_DECLS
+
+#endif /* __OTTIE_PARSER_PRIVATE_H__ */

ottie/ottiepathshape.c

@@ -0,0 +1,105 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#include "config.h"
+
+#include "ottiepathshapeprivate.h"
+
+#include "ottiepathvalueprivate.h"
+#include "ottieparserprivate.h"
+#include "ottieshapeprivate.h"
+
+#include <glib/gi18n-lib.h>
+
+struct _OttiePathShape
+{
+  OttieShape parent;
+
+  double direction;
+  OttiePathValue path;
+};
+
+struct _OttiePathShapeClass
+{
+  OttieShapeClass parent_class;
+};
+
+G_DEFINE_TYPE (OttiePathShape, ottie_path_shape, OTTIE_TYPE_SHAPE)
+
+static void
+ottie_path_shape_render (OttieShape  *shape,
+                         OttieRender *render,
+                         double       timestamp)
+{
+  OttiePathShape *self = OTTIE_PATH_SHAPE (shape);
+
+  ottie_render_add_path (render,
+                         ottie_path_value_get (&self->path,
+                                               timestamp,
+                                               self->direction));
+}
+
+static void
+ottie_path_shape_dispose (GObject *object)
+{
+  OttiePathShape *self = OTTIE_PATH_SHAPE (object);
+
+  ottie_path_value_clear (&self->path);
+
+  G_OBJECT_CLASS (ottie_path_shape_parent_class)->dispose (object);
+}
+
+static void
+ottie_path_shape_class_init (OttiePathShapeClass *klass)
+{
+  OttieShapeClass *shape_class = OTTIE_SHAPE_CLASS (klass);
+  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
+
+  shape_class->render = ottie_path_shape_render;
+
+  gobject_class->dispose = ottie_path_shape_dispose;
+}
+
+static void
+ottie_path_shape_init (OttiePathShape *self)
+{
+  ottie_path_value_init (&self->path);
+}
+
+OttieShape *
+ottie_path_shape_parse (JsonReader *reader)
+{
+  OttieParserOption options[] = {
+    OTTIE_PARSE_OPTIONS_SHAPE,
+    { "d", ottie_parser_option_double, G_STRUCT_OFFSET (OttiePathShape, direction) },
+    { "ks", ottie_path_value_parse, G_STRUCT_OFFSET (OttiePathShape, path) },
+  };
+  OttiePathShape *self;
+
+  self = g_object_new (OTTIE_TYPE_PATH_SHAPE, NULL);
+
+  if (!ottie_parser_parse_object (reader, "path shape", options, G_N_ELEMENTS (options), self))
+    {
+      g_object_unref (self);
+      return NULL;
+    }
+
+  return OTTIE_SHAPE (self);
+}
+

ottie/ottiepathshapeprivate.h

@@ -0,0 +1,45 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#ifndef __OTTIE_PATH_SHAPE_PRIVATE_H__
+#define __OTTIE_PATH_SHAPE_PRIVATE_H__
+
+#include "ottieshapeprivate.h"
+
+#include <json-glib/json-glib.h>
+
+G_BEGIN_DECLS
+
+#define OTTIE_TYPE_PATH_SHAPE         (ottie_path_shape_get_type ())
+#define OTTIE_PATH_SHAPE(o)           (G_TYPE_CHECK_INSTANCE_CAST ((o), OTTIE_TYPE_PATH_SHAPE, OttiePathShape))
+#define OTTIE_PATH_SHAPE_CLASS(k)     (G_TYPE_CHECK_CLASS_CAST ((k), OTTIE_TYPE_PATH_SHAPE, OttiePathShapeClass))
+#define OTTIE_IS_PATH_SHAPE(o)        (G_TYPE_CHECK_INSTANCE_TYPE ((o), OTTIE_TYPE_PATH_SHAPE))
+#define OTTIE_IS_PATH_SHAPE_CLASS(k)  (G_TYPE_CHECK_CLASS_TYPE ((k), OTTIE_TYPE_PATH_SHAPE))
+#define OTTIE_PATH_SHAPE_GET_CLASS(o) (G_TYPE_INSTANCE_GET_CLASS ((o), OTTIE_TYPE_PATH_SHAPE, OttiePathShapeClass))
+
+typedef struct _OttiePathShape OttiePathShape;
+typedef struct _OttiePathShapeClass OttiePathShapeClass;
+
+GType                   ottie_path_shape_get_type               (void) G_GNUC_CONST;
+
+OttieShape *            ottie_path_shape_parse                  (JsonReader             *reader);
+
+G_END_DECLS
+
+#endif /* __OTTIE_PATH_SHAPE_PRIVATE_H__ */

ottie/ottiepathvalue.c

@@ -0,0 +1,402 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#include "config.h"
+
+#include "ottiepathvalueprivate.h"
+
+#include "ottieparserprivate.h"
+
+#include <glib/gi18n-lib.h>
+
+typedef struct _OttieContour OttieContour;
+typedef struct _OttieCurve OttieCurve;
+typedef struct _OttiePath OttiePath;
+
+struct _OttieCurve {
+  double point[2];
+  double in[2];
+  double out[2];
+};
+
+struct _OttieContour {
+  gboolean closed;
+  guint n_curves;
+  OttieCurve curves[0];
+};
+
+struct _OttiePath {
+  guint ref_count;
+  guint n_contours;
+  OttieContour *contours[];
+};
+
+static OttieContour *
+ottie_contour_renew (OttieContour *path,
+                     guint         n_curves)
+{
+  OttieContour *self;
+
+  self = g_realloc (path, sizeof (OttieContour) + n_curves * sizeof (OttieCurve));
+  self->n_curves = n_curves;
+
+  return self;
+}
+
+static OttieContour *
+ottie_contour_new (gboolean closed,
+                   guint    n_curves)
+{
+  OttieContour *self;
+
+  self = g_malloc0 (sizeof (OttieContour) + n_curves * sizeof (OttieCurve));
+  self->closed = closed;
+  self->n_curves = n_curves;
+
+  return self;
+}
+
+static void
+ottie_contour_free (OttieContour *path)
+{
+  g_free (path);
+}
+
+static gboolean
+ottie_parse_value_parse_numbers (JsonReader *reader,
+                                 gsize       offset,
+                                 gpointer    data)
+{
+  return ottie_parser_parse_array (reader, "number",
+                                   2, 2, NULL,
+                                   offset, sizeof (double),
+                                   ottie_parser_option_double, data);
+}
+
+#define MAKE_OPEN_CONTOUR (NULL)
+#define MAKE_CLOSED_CONTOUR GSIZE_TO_POINTER(1)
+static gboolean
+ottie_parse_value_parse_curve_array (JsonReader *reader,
+                                     gsize       offset,
+                                     gpointer    data)
+{
+  /* Attention: The offset value here is to the point in the curve, not 
+   * to the target */
+  OttieContour **target = (OttieContour **) data;
+  OttieContour *path = *target;
+  guint n_curves;
+
+  n_curves = json_reader_count_elements (reader);
+  if (path == MAKE_OPEN_CONTOUR)
+    path = ottie_contour_new (FALSE, n_curves);
+  else if (path == MAKE_CLOSED_CONTOUR)
+    path = ottie_contour_new (TRUE, n_curves);
+  else if (n_curves < path->n_curves)
+    path = ottie_contour_renew (path, n_curves);
+  else if (n_curves > path->n_curves)
+    n_curves = path->n_curves;
+
+  *target = path;
+
+  return ottie_parser_parse_array (reader, "path array",
+                                   0, path->n_curves, NULL,
+                                   offset, sizeof (OttieCurve),
+                                   ottie_parse_value_parse_numbers, &path->curves[0]);
+}
+
+static gboolean
+ottie_parser_value_parse_closed (JsonReader *reader,
+                                 gsize       offset,
+                                 gpointer    data)
+{
+  OttieContour **target = (OttieContour **) data;
+  gboolean b;
+
+  b = json_reader_get_boolean_value (reader);
+  if (json_reader_get_error (reader))
+    {
+      ottie_parser_emit_error (reader, json_reader_get_error (reader));
+      return FALSE;
+    }
+  
+  if (*target == MAKE_OPEN_CONTOUR || *target == MAKE_CLOSED_CONTOUR)
+    {
+      if (b)
+        *target = MAKE_CLOSED_CONTOUR;
+      else
+        *target = MAKE_OPEN_CONTOUR;
+    }
+  else
+    (*target)->closed = b;
+
+  return TRUE;
+}
+
+static gboolean
+ottie_path_value_parse_contour (JsonReader *reader,
+                                gsize       offset,
+                                gpointer    data)
+{
+  OttieContour **target = (OttieContour **) ((guint8 *) data + offset);
+  OttieParserOption options[] = {
+    { "c", ottie_parser_value_parse_closed, 0 },
+    { "i", ottie_parse_value_parse_curve_array, G_STRUCT_OFFSET (OttieCurve, in) },
+    { "o", ottie_parse_value_parse_curve_array, G_STRUCT_OFFSET (OttieCurve, out) },
+    { "v", ottie_parse_value_parse_curve_array, G_STRUCT_OFFSET (OttieCurve, point) },
+  };
+
+  g_assert (*target == NULL);
+  *target = MAKE_CLOSED_CONTOUR;
+
+  if (!ottie_parser_parse_object (reader, "contour", options, G_N_ELEMENTS (options), target))
+    {
+      if (*target != MAKE_OPEN_CONTOUR && *target != MAKE_CLOSED_CONTOUR)
+        g_clear_pointer (target, ottie_contour_free);
+      *target = NULL;
+      return FALSE;
+    }
+
+  if (*target == MAKE_OPEN_CONTOUR)
+    *target = ottie_contour_new (FALSE, 0);
+  else if (*target == MAKE_CLOSED_CONTOUR)
+    *target = ottie_contour_new (TRUE, 0);
+
+  return TRUE;
+}
+
+static OttiePath *
+ottie_path_new (gsize n_contours)
+{
+  OttiePath *self;
+
+  self = g_malloc0 (sizeof (OttiePath) + sizeof (OttieContour *) * n_contours);
+  self->ref_count = 1;
+  self->n_contours = n_contours;
+
+  return self;
+}
+
+static OttiePath *
+ottie_path_ref (OttiePath *self)
+{
+  self->ref_count++;
+
+  return self;
+}
+
+static void
+ottie_path_unref (OttiePath *self)
+{
+  self->ref_count--;
+  if (self->ref_count > 0)
+    return;
+
+  for (guint i = 0; i < self->n_contours; i++)
+    {
+      g_clear_pointer (&self->contours[i], ottie_contour_free);
+    }
+
+  g_free (self);
+}
+
+static gboolean
+ottie_path_value_parse_one (JsonReader *reader,
+                            gsize       offset,
+                            gpointer    data)
+{
+  OttiePath **target = (OttiePath **) ((guint8 *) data + offset);
+  OttiePath *path;
+
+  if (json_reader_is_array (reader))
+    path = ottie_path_new (json_reader_count_elements (reader));
+  else
+    path = ottie_path_new (1);
+
+  if (!ottie_parser_parse_array (reader, "path",
+                                 path->n_contours, path->n_contours, NULL,
+                                 G_STRUCT_OFFSET (OttiePath, contours),
+                                 sizeof (OttieContour *),
+                                 ottie_path_value_parse_contour, path))
+    {
+      ottie_path_unref (path);
+      return FALSE;
+    }
+
+  g_clear_pointer (target, ottie_path_unref);
+  *target = path;
+
+  return TRUE;
+}
+
+static OttieContour *
+ottie_contour_interpolate (const OttieContour *start,
+                           const OttieContour *end,
+                           double              progress)
+{
+  OttieContour *self = ottie_contour_new (start->closed || end->closed,
+                                          MIN (start->n_curves, end->n_curves));
+
+  for (gsize i = 0; i < self->n_curves; i++)
+    {
+      self->curves[i].point[0] = start->curves[i].point[0] + progress * (end->curves[i].point[0] - start->curves[i].point[0]);
+      self->curves[i].point[1] = start->curves[i].point[1] + progress * (end->curves[i].point[1] - start->curves[i].point[1]);
+      self->curves[i].in[0] = start->curves[i].in[0] + progress * (end->curves[i].in[0] - start->curves[i].in[0]);
+      self->curves[i].in[1] = start->curves[i].in[1] + progress * (end->curves[i].in[1] - start->curves[i].in[1]);
+      self->curves[i].out[0] = start->curves[i].out[0] + progress * (end->curves[i].out[0] - start->curves[i].out[0]);
+      self->curves[i].out[1] = start->curves[i].out[1] + progress * (end->curves[i].out[1] - start->curves[i].out[1]);
+    }
+
+  return self;
+}
+
+static OttiePath *
+ottie_path_interpolate (const OttiePath *start,
+                        const OttiePath *end,
+                        double           progress)
+{
+  OttiePath *self = ottie_path_new (MIN (start->n_contours, end->n_contours));
+
+  for (gsize i = 0; i < self->n_contours; i++)
+    {
+      self->contours[i] = ottie_contour_interpolate (start->contours[i],
+                                                     end->contours[i],
+                                                     progress);
+    }
+
+  return self;
+}
+
+#define OTTIE_KEYFRAMES_NAME ottie_path_keyframes
+#define OTTIE_KEYFRAMES_TYPE_NAME OttieContourKeyframes
+#define OTTIE_KEYFRAMES_ELEMENT_TYPE OttiePath *
+#define OTTIE_KEYFRAMES_COPY_FUNC ottie_path_ref
+#define OTTIE_KEYFRAMES_FREE_FUNC ottie_path_unref
+#define OTTIE_KEYFRAMES_PARSE_FUNC ottie_path_value_parse_one
+#define OTTIE_KEYFRAMES_INTERPOLATE_FUNC ottie_path_interpolate
+#include "ottiekeyframesimpl.c"
+
+void
+ottie_path_value_init (OttiePathValue *self)
+{
+  self->is_static = TRUE;
+  self->static_value = NULL;
+}
+
+void
+ottie_path_value_clear (OttiePathValue *self)
+{
+  if (self->is_static)
+    g_clear_pointer (&self->static_value, ottie_path_unref);
+  else
+    g_clear_pointer (&self->keyframes, ottie_path_keyframes_free);
+}
+
+static GskPath *
+ottie_path_build (OttiePath *self,
+                  gboolean   reverse)
+{
+  GskPathBuilder *builder;
+
+  if (reverse)
+    g_warning ("FIXME: Make paths reversible");
+
+  builder = gsk_path_builder_new ();
+  for (gsize i = 0; i < self->n_contours; i++)
+    {
+      OttieContour *contour = self->contours[i];
+      if (contour->n_curves == 0)
+        continue;
+
+      gsk_path_builder_move_to (builder,
+                                contour->curves[0].point[0], contour->curves[0].point[1]);
+      for (guint j = 1; j < contour->n_curves; j++)
+        {
+          gsk_path_builder_curve_to (builder,
+                                     contour->curves[j-1].point[0] + contour->curves[j-1].out[0],
+                                     contour->curves[j-1].point[1] + contour->curves[j-1].out[1],
+                                     contour->curves[j].point[0] + contour->curves[j].in[0],
+                                     contour->curves[j].point[1] + contour->curves[j].in[1],
+                                     contour->curves[j].point[0],
+                                     contour->curves[j].point[1]);
+        }
+      if (contour->closed)
+        {
+          gsk_path_builder_curve_to (builder,
+                                     contour->curves[contour->n_curves-1].point[0] + contour->curves[contour->n_curves-1].out[0],
+                                     contour->curves[contour->n_curves-1].point[1] + contour->curves[contour->n_curves-1].out[1],
+                                     contour->curves[0].point[0] + contour->curves[0].in[0],
+                                     contour->curves[0].point[1] + contour->curves[0].in[1],
+                                     contour->curves[0].point[0],
+                                     contour->curves[0].point[1]);
+          gsk_path_builder_close (builder);
+        }
+    }
+
+  return gsk_path_builder_free_to_path (builder);
+}
+
+GskPath *
+ottie_path_value_get (OttiePathValue *self,
+                      double          timestamp,
+                      gboolean        reverse)
+{
+  if (self->is_static)
+    return ottie_path_build (self->static_value, reverse);
+  
+  return ottie_path_build (ottie_path_keyframes_get (self->keyframes, timestamp), reverse);
+}
+
+gboolean
+ottie_path_value_parse (JsonReader *reader,
+                        gsize       offset,
+                        gpointer    data)
+{
+  OttiePathValue *self = (OttiePathValue *) ((guint8 *) data + GPOINTER_TO_SIZE (offset));
+
+  if (json_reader_read_member (reader, "k"))
+    {
+      if (!json_reader_is_array (reader))
+        {
+          if (!ottie_path_value_parse_one (reader, 0, &self->static_value))
+            {
+              json_reader_end_member (reader);
+              return FALSE;
+            }
+          self->is_static = TRUE;
+        }
+      else
+        {
+          self->keyframes = ottie_path_keyframes_parse (reader);
+          if (self->keyframes == NULL)
+            {
+              json_reader_end_member (reader);
+              return FALSE;
+            }
+          self->is_static = FALSE;
+        }
+    }
+  else
+    {
+      ottie_parser_error_syntax (reader, "Property is not a path value");
+    }
+  json_reader_end_member (reader);
+
+  return TRUE;
+}
+

ottie/ottiepathvalueprivate.h

@@ -0,0 +1,53 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#ifndef __OTTIE_PATH_VALUE_PRIVATE_H__
+#define __OTTIE_PATH_VALUE_PRIVATE_H__
+
+#include <json-glib/json-glib.h>
+
+#include <gsk/gsk.h>
+
+G_BEGIN_DECLS
+
+typedef struct _OttiePathValue OttiePathValue;
+
+struct _OttiePathValue
+{
+  gboolean is_static;
+  union {
+    gpointer static_value;
+    gpointer keyframes;
+  };
+};
+
+void                      ottie_path_value_init                 (OttiePathValue         *self);
+void                      ottie_path_value_clear                (OttiePathValue         *self);
+
+GskPath *                 ottie_path_value_get                  (OttiePathValue         *self,
+                                                                 double                  timestamp,
+                                                                 gboolean                reverse);
+
+gboolean                  ottie_path_value_parse                (JsonReader             *reader,
+                                                                 gsize                   offset,
+                                                                 gpointer                data);
+
+G_END_DECLS
+
+#endif /* __OTTIE_PATH_VALUE_PRIVATE_H__ */

ottie/ottieplayer.c

@@ -0,0 +1,490 @@
+/*
+ * Copyright © 2020 Benjamin Otte
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library. If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Authors: Benjamin Otte <otte@gnome.org>
+ */
+
+#include "config.h"
+
+#include "ottieplayer.h"
+
+#include "ottiecreation.h"
+#include "ottiepaintable.h"
+
+#include <glib/gi18n.h>
+
+struct _OttiePlayer
+{
+  GObject parent_instance;
+
+  GFile *file;
+
+  OttieCreation *creation;
+  OttiePaintable *paintable;
+  gint64 time_offset;
+  guint timer_cb;
+};
+
+struct _OttiePlayerClass
+{
+  GObjectClass parent_class;
+};
+
+enum {
+  PROP_0,
+  PROP_FILE,
+
+  N_PROPS,
+};
+
+static GParamSpec *properties[N_PROPS] = { NULL, };
+
+static void
+ottie_player_paintable_snapshot (GdkPaintable *paintable,
+                                 GdkSnapshot  *snapshot,
+                                 double        width,
+                                 double        height)
+{
+  OttiePlayer *self = OTTIE_PLAYER (paintable);
+
+  gdk_paintable_snapshot (GDK_PAINTABLE (self->paintable), snapshot, width, height);
+}
+
+static int
+ottie_player_paintable_get_intrinsic_width (GdkPaintable *paintable)
+{
+  OttiePlayer *self = OTTIE_PLAYER (paintable);
+
+  return gdk_paintable_get_intrinsic_width (GDK_PAINTABLE (self->paintable));
+}
+
+static int
+ottie_player_paintable_get_intrinsic_height (GdkPaintable *paintable)
+{
+  OttiePlayer *self = OTTIE_PLAYER (paintable);
+
+  return gdk_paintable_get_intrinsic_height (GDK_PAINTABLE (self->paintable));
+}
+
+static void
+ottie_player_paintable_init (GdkPaintableInterface *iface)
+{
+  iface->snapshot = ottie_player_paintable_snapshot;
+  iface->get_intrinsic_width = ottie_player_paintable_get_intrinsic_width;
+  iface->get_intrinsic_height = ottie_player_paintable_get_intrinsic_height;
+}
+
+G_DEFINE_TYPE_EXTENDED (OttiePlayer, ottie_player, GTK_TYPE_MEDIA_STREAM, 0,
+                        G_IMPLEMENT_INTERFACE (GDK_TYPE_PAINTABLE,
+                                               ottie_player_paintable_init))
+
+static gboolean
+ottie_player_timer_cb (gpointer data)
+{
+  OttiePlayer *self = OTTIE_PLAYER (data);
+  gint64 timestamp;
+
+  timestamp = g_get_monotonic_time () - self->time_offset;
+  if (timestamp > ottie_paintable_get_duration (self->paintable))
+    {
+      if (gtk_media_stream_get_loop (GTK_MEDIA_STREAM (self)))
+        {
+          timestamp %= ottie_paintable_get_duration (self->paintable);
+        }
+      else
+        {
+          timestamp = ottie_paintable_get_duration (self->paintable);
+          gtk_media_stream_stream_ended (GTK_MEDIA_STREAM (self));
+        }
+    }
+  ottie_paintable_set_timestamp (self->paintable, timestamp);
+  gtk_media_stream_update (GTK_MEDIA_STREAM (self), timestamp);
+
+  return G_SOURCE_CONTINUE;
+}
+
+static gboolean
+ottie_player_play (GtkMediaStream *stream)
+{
+  OttiePlayer *self = OTTIE_PLAYER (stream);
+  double frame_rate;
+
+  frame_rate = ottie_creation_get_frame_rate (self->creation);
+  if (frame_rate <= 0)
+    return FALSE;
+
+  self->time_offset = g_get_monotonic_time () - ottie_paintable_get_timestamp (self->paintable);
+  self->timer_cb = g_timeout_add (1000 / frame_rate, ottie_player_timer_cb, self);
+
+  return TRUE;
+}
+
+static void
+ottie_player_pause (GtkMediaStream *stream)
+{
+  OttiePlayer *self = OTTIE_PLAYER (stream);
+
+  g_clear_handle_id (&self->timer_cb, g_source_remove);
+}
+
+static void
+ottie_player_seek (GtkMediaStream *stream,
+                   gint64          timestamp)
+{
+  OttiePlayer *self = OTTIE_PLAYER (stream);
+
+  if (!ottie_creation_is_prepared (self->creation))
+    gtk_media_stream_seek_failed (stream);
+
+  ottie_paintable_set_timestamp (self->paintable, timestamp);
+  self->time_offset = g_get_monotonic_time () - timestamp;
+
+  gtk_media_stream_seek_success (stream);
+  gtk_media_stream_update (stream, timestamp);
+}
+
+static void
+ottie_player_set_property (GObject      *object,
+                           guint         prop_id,
+                           const GValue *value,
+                           GParamSpec   *pspec)
+
+{
+  OttiePlayer *self = OTTIE_PLAYER (object);
+
+  switch (prop_id)
+    {
+    case PROP_FILE:
+      ottie_player_set_file (self, g_value_get_object (value));
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void
+ottie_player_get_property (GObject    *object,
+                           guint       prop_id,
+                           GValue     *value,
+                           GParamSpec *pspec)
+{
+  OttiePlayer *self = OTTIE_PLAYER (object);
+
+  switch (prop_id)
+    {
+    case PROP_FILE:
+      g_value_set_object (value, self->file);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void
+ottie_player_dispose (GObject *object)
+{
+  OttiePlayer *self = OTTIE_PLAYER (object);
+
+  if (self->paintable)
+    {
+      g_signal_handlers_disconnect_by_func (self->paintable, gdk_paintable_invalidate_contents, self);
+      g_signal_handlers_disconnect_by_func (self->paintable, gdk_paintable_invalidate_size, self);
+      g_clear_object (&self->paintable);
+    }
+  g_clear_object (&self->creation);
+
+  G_OBJECT_CLASS (ottie_player_parent_class)->dispose (object);
+}
+
+static void
+ottie_player_class_init (OttiePlayerClass *klass)
+{
+  GtkMediaStreamClass *stream_class = GTK_MEDIA_STREAM_CLASS (klass);
+  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
+
+  stream_class->play = ottie_player_play;
+  stream_class->pause = ottie_player_pause;
+  stream_class->seek = ottie_player_seek;
+
+  gobject_class->get_property = ottie_player_get_property;
+  gobject_class->set_property = ottie_player_set_property;
+  gobject_class->dispose = ottie_player_dispose;
+
+  /**
+   * OttiePlayer:file
+   *
+   * The played file or %NULL.
+   */
+  properties[PROP_FILE] =
+    g_param_spec_object ("file",
+                         _("File"),
+                         _("The played file"),
+                         G_TYPE_FILE,
+                         G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);
+
+  g_object_class_install_properties (gobject_class, N_PROPS, properties);
+}
+
+static void
+ottie_player_prepared_cb (OttieCreation *creation,
+                          GParamSpec    *pspec,
+                          OttiePlayer   *self)
+{
+  if (ottie_creation_is_prepared (creation))
+    gtk_media_stream_stream_prepared (GTK_MEDIA_STREAM (self),
+                                      FALSE,
+                                      TRUE,
+                                      TRUE,
+                                      ottie_paintable_get_duration (self->paintable));
+  else
+    gtk_media_stream_stream_unprepared (GTK_MEDIA_STREAM (self));
+
+  ottie_paintable_set_timestamp (self->paintable, 0);
+}
+
+static void
+ottie_player_init (OttiePlayer *self)
+{
+  self->creation = ottie_creation_new ();
+  g_signal_connect (self->creation, "notify::prepared", G_CALLBACK (ottie_player_prepared_cb), self);
+  self->paintable = ottie_paintable_new (self->creation);
+  g_signal_connect_swapped (self->paintable, "invalidate-contents", G_CALLBACK (gdk_paintable_invalidate_contents), self);
+  g_signal_connect_swapped (self->paintable, "invalidate-size", G_CALLBACK (gdk_paintable_invalidate_size), self);
+}
+
+/**
+ * ottie_player_new:
+ *
+ * Creates a new Ottie player.
+ *
+ * Returns: (transfer full): a new #OttiePlayer
+ **/
+OttiePlayer *
+ottie_player_new (void)
+{
+  return g_object_new (OTTIE_TYPE_PLAYER, NULL);
+}
+
+/**
+ * ottie_player_new_for_file:
+ * @file: (nullable): a #GFile
+ *
+ * Creates a new #OttiePlayer playing the given @file. If the file
+ * isn’t found or can’t be loaded, the resulting #OttiePlayer be empty.
+ *
+ * Returns: a new #OttiePlayer
+ **/
+OttiePlayer*
+ottie_player_new_for_file (GFile *file)
+{
+  g_return_val_if_fail (file == NULL || G_IS_FILE (file), NULL);
+
+  return g_object_new (OTTIE_TYPE_PLAYER,
+                       "file", file,
+                       NULL);
+}
+
+/**
+ * ottie_player_new_for_filename:
+ * @filename: (type filename) (nullable): a filename
+ *
+ * Creates a new #OttiePlayer displaying the file @filename.
+ *
+ * This is a utility function that calls ottie_player_new_for_file().
+ * See that function for details.
+ *
+ * Returns: a new #OttiePlayer
+ **/
+OttiePlayer*
+ottie_player_new_for_filename (const char *filename)
+{
+  OttiePlayer *result;
+  GFile *file;
+
+  if (filename)
+    file = g_file_new_for_path (filename);
+  else
+    file = NULL;
+
+  result = ottie_player_new_for_file (file);
+
+  if (file)
+    g_object_unref (file);
+
+  return result;
+}
+
+/**
+ * ottie_player_new_for_resource:
+ * @resource_path: (nullable): resource path to play back
+ *
+ * Creates a new #OttiePlayer displaying the file @resource_path.
+ *
+ * This is a utility function that calls ottie_player_new_for_file().
+ * See that function for details.
+ *
+ * Returns: a new #OttiePlayer
+ **/
+OttiePlayer *
+ottie_player_new_for_resource (const char *resource_path)
+{
+  OttiePlayer *result;
+  GFile *file;
+
+  if (resource_path)
+    {
+      char *uri, *escaped;
+
+      escaped = g_uri_escape_string (resource_path,
+                                     G_URI_RESERVED_CHARS_ALLOWED_IN_PATH, FALSE);
+      uri = g_strconcat ("resource://", escaped, NULL);
+      g_free (escaped);
+
+      file = g_file_new_for_uri (uri);
+      g_free (uri);
+    }
+  else
+    {
+      file = NULL;
+    }
+
+  result = ottie_player_new_for_file (file);
+
+  if (file)
+    g_object_unref (file);
+
+  return result;
+}
+
+/**
+ * ottie_player_set_file:
+ * @self: a #OttiePlayer
+ * @file: (nullable): a %GFile or %NULL
+ *
+ * Makes @self load and display @file.
+ *
+ * See ottie_player_new_for_file() for details.
+ **/
+void
+ottie_player_set_file (OttiePlayer *self,
+                       GFile      *file)
+{
+  g_return_if_fail (OTTIE_IS_PLAYER (self));
+  g_return_if_fail (file == NULL || G_IS_FILE (file));
+
+  if (self->file == file)
+    return;
+
+  g_object_freeze_notify (G_OBJECT (self));
+
+  g_set_object (&self->file, file);
+  ottie_creation_load_file (self->creation, file);
+
+  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_FILE]);
+
+  g_object_thaw_notify (G_OBJECT (self));
+}
+
+/**
+ * ottie_player_get_file:
+ * @self: a #OttiePlayer
+ *
+ * Gets the #GFile currently displayed if @self is displaying a file.
+ * If @self is not displaying a file, then %NULL is returned.
+ *
+ * Returns: (nullable) (transfer none): The #GFile displayed by @self.
+ **/
+GFile *
+ottie_player_get_file (OttiePlayer *self)
+{
+  g_return_val_if_fail (OTTIE_IS_PLAYER (self), FALSE);
+
+  return self->file;
+}
+
+/**
+ * ottie_player_set_filename:
+ * @self: a #OttiePlayer
+ * @filename: (nullable): the filename to play
+ *
+ * Makes @self load and display the given @filename.
+ *
+ * This is a utility function that calls ottie_player_set_file().
+ **/
+void
+ottie_player_set_filename (OttiePlayer *self,
+                          const char *filename)
+{
+  GFile *file;
+
+  g_return_if_fail (OTTIE_IS_PLAYER (self));
+
+  if (filename)
+    file = g_file_new_for_path (filename);
+  else
+    file = NULL;
+
+  ottie_player_set_file (self, file);
+
+  if (file)
+    g_object_unref (file);
+}
+
+/**
+ * ottie_player_set_resource:
+ * @self: a #OttiePlayer
+ * @resource_path: (nullable): the resource to set
+ *
+ * Makes @self load and display the resource at the given
+ * @resource_path.
+ *
+ * This is a utility function that calls ottie_player_set_file(),
+ **/
+void
+ottie_player_set_resource (OttiePlayer *self,
+                          const char *resource_path)
+{
+  GFile *file;
+
+  g_return_if_fail (OTTIE_IS_PLAYER (self));
+
+  if (resource_path)
+    {
+      char *uri, *escaped;
+
+      escaped = g_uri_escape_string (resource_path,
+                                     G_URI_RESERVED_CHARS_ALLOWED_IN_PATH, FALSE);
+      uri = g_strconcat ("resource://", escaped, NULL);
+      g_free (escaped);
+
+      file = g_file_new_for_uri (uri);
+      g_free (uri);
+    }
+  else
+    {
+      file = NULL;
+    }
+
+  ottie_player_set_file (self, file);
+
+  if (file)
+    g_object_unref (file);
+}
+