Make points stack-allocated

This does the necessary reshuffling to make GskPathPoint
a stack-allocated struct.

demos/gtk-demo/demo.gresource.xml

@@ -335,6 +335,9 @@
     <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>
@@ -420,6 +423,9 @@
   <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

@@ -72,6 +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',

demos/gtk-demo/path_fill.c

@@ -0,0 +1,362 @@
+/* Path/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"
+
+#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 need to disconnect the signals here that we set up elsewhere
+ */
+static void 
+gtk_path_paintable_dispose (GObject *object)
+{
+  GtkPathPaintable *self = GTK_PATH_PAINTABLE (object);
+
+  if (self->background)
+    {
+      g_signal_handlers_disconnect_by_func (self->background, gdk_paintable_invalidate_contents, self);
+      g_signal_handlers_disconnect_by_func (self->background, gdk_paintable_invalidate_size, self);
+      g_clear_object (&self->background);
+    }
+
+  G_OBJECT_CLASS (gtk_path_paintable_parent_class)->dispose (object);
+}
+
+static void
+gtk_path_paintable_class_init (GtkPathPaintableClass *klass)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+
+  object_class->dispose = gtk_path_paintable_dispose;
+}
+
+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_object_ref (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_QUAD:
+      gsk_path_builder_quad_to (builder, pts[1].x, pts[1].y, pts[2].x, pts[2].y);
+      break;
+
+    case GSK_PATH_CUBIC:
+      gsk_path_builder_cubic_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;
+  GskPathPoint point;
+  graphene_point_t pos;
+  graphene_vec2_t tangent;
+  GskStroke *stroke;
+
+  path = gsk_path_measure_get_path (measure);
+
+  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);
+
+  if (gsk_path_measure_get_point (measure,
+                                   (progress > 1 ? (progress - 1) : progress) * gsk_path_measure_get_length (measure), &point))
+    {
+      gsk_path_point_get_position (&point, &pos);
+      gsk_path_point_get_tangent (&point, GSK_PATH_END, &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_content_fit (GTK_PICTURE (picture), GTK_CONTENT_FIT_CONTAIN);
+      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_window_present (GTK_WINDOW (window));
+  else
+    gtk_window_destroy (GTK_WINDOW (window));
+
+  return window;
+}

demos/gtk-demo/path_maze.c

@@ -0,0 +1,346 @@
+/* Path/Maze
+ *
+ * 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)
+{
+  GskPathPoint point;
+  graphene_point_t pos;
+
+  if (!self->active)
+    return;
+
+  if (gsk_path_get_closest_point (self->path, &GRAPHENE_POINT_INIT (x, y), INFINITY, &point))
+    {
+      gsk_path_point_get_position (&point, &pos);
+
+      if (graphene_point_distance (&pos, &GRAPHENE_POINT_INIT (x, y), NULL, 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] = { FALSE, FALSE, FALSE, FALSE };
+  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_window_present (GTK_WINDOW (window));
+  else
+    gtk_window_destroy (GTK_WINDOW (window));
+
+  return window;
+}

demos/gtk-demo/path_text.c

@@ -0,0 +1,612 @@
+/* Path/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,
+                       graphene_point_t *out_offset)
+{
+  PangoLayout *layout;
+  PangoFontDescription *desc;
+  GskPathBuilder *builder;
+  GskPath *result;
+
+  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);
+
+  builder = gsk_path_builder_new ();
+  gsk_path_builder_add_layout (builder, layout);
+  result = gsk_path_builder_free_to_path (builder);
+
+  if (out_offset)
+    graphene_point_init (out_offset, 0, - pango_layout_get_baseline (layout) / (double) PANGO_SCALE);
+  g_object_unref (layout);
+
+  return result;
+}
+
+typedef struct
+{
+  GskPathMeasure *measure;
+  GskPathBuilder *builder;
+  graphene_point_t offset;
+  double scale;
+} GtkPathTransform;
+
+static void
+gtk_path_transform_point (GskPathMeasure         *measure,
+                          const graphene_point_t *pt,
+                          const graphene_point_t *offset,
+                          float                   scale,
+                          graphene_point_t       *res)
+{
+  graphene_vec2_t tangent;
+  GskPathPoint point;
+
+  if (gsk_path_measure_get_point (measure, (pt->x + offset->x) * scale, &point))
+    {
+      gsk_path_point_get_position (&point, res);
+      gsk_path_point_get_tangent (&point, GSK_PATH_END, &tangent);
+
+      res->x -= (pt->y + offset->y) * scale * graphene_vec2_get_y (&tangent);
+      res->y += (pt->y + offset->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->offset, 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->offset, transform->scale, &res);
+        gsk_path_builder_line_to (transform->builder, res.x, res.y);
+      }
+      break;
+
+    case GSK_PATH_QUAD:
+      {
+        graphene_point_t res[2];
+        gtk_path_transform_point (transform->measure, &pts[1], &transform->offset, transform->scale, &res[0]);
+        gtk_path_transform_point (transform->measure, &pts[2], &transform->offset, transform->scale, &res[1]);
+        gsk_path_builder_quad_to (transform->builder, res[0].x, res[0].y, res[1].x, res[1].y);
+      }
+      break;
+
+    case GSK_PATH_CUBIC:
+      {
+        graphene_point_t res[3];
+        gtk_path_transform_point (transform->measure, &pts[1], &transform->offset, transform->scale, &res[0]);
+        gtk_path_transform_point (transform->measure, &pts[2], &transform->offset, transform->scale, &res[1]);
+        gtk_path_transform_point (transform->measure, &pts[3], &transform->offset, transform->scale, &res[2]);
+        gsk_path_builder_cubic_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->offset, transform->scale, &res[0]);
+        gtk_path_transform_point (transform->measure, &pts[2], &transform->offset, 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,
+                    const graphene_point_t *offset)
+{
+  GtkPathTransform transform = { measure, gsk_path_builder_new (), *offset };
+  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, -1, 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;
+  graphene_point_t offset;
+
+  gtk_path_widget_clear_text_path (self);
+
+  if (self->line_measure == NULL)
+    return;
+
+  path = create_path_from_text (GTK_WIDGET (self), self->text, &offset);
+  self->text_path = gtk_path_transform (self->line_measure, path, &offset);
+
+  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_cubic_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, 0.6 }, &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)
+    {
+      GskPathBuilder *builder;
+
+      /* 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);
+
+      /* 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);
+    }
+
+  if (self->line_closest >= 0)
+    {
+      GskPathBuilder *builder;
+      GskPathPoint point;
+      graphene_point_t closest;
+
+      builder = gsk_path_builder_new ();
+      if (gsk_path_measure_get_point (self->line_measure, self->line_closest, &point))
+        {
+          gsk_path_point_get_position (&point, &closest);
+          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);
+        }
+    }
+}
+
+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)
+{
+  GskPathPoint point;
+  graphene_point_t pos;
+
+  if (gsk_path_get_closest_point (gsk_path_measure_get_path (self->line_measure),
+                                  &GRAPHENE_POINT_INIT (x, y),
+                                  INFINITY,
+                                  &point))
+    {
+      gsk_path_point_get_position (&point, &pos);
+      self->line_closest = graphene_point_distance (&pos, &GRAPHENE_POINT_INIT (x, y), NULL, 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_window_present (GTK_WINDOW (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>

docs/reference/gtk/gtk4-path-tool.rst

@@ -0,0 +1,121 @@
+.. _gtk4-path-tool(1):
+
+=================
+gtk4-path-tool
+=================
+
+-----------------------
+GskPath Utility
+-----------------------
+
+SYNOPSIS
+--------
+|   **gtk4-path-tool** <COMMAND> [OPTIONS...] <PATH>
+|
+|   **gtk4-path-tool** decompose [OPTIONS...] <PATH>
+|   **gtk4-path-tool** restrict [OPTIONS...] <PATH>
+|   **gtk4-path-tool** show [OPTIONS...] <PATH>
+|   **gtk4-path-tool** render [OPTIONS...] <PATH>
+|   **gtk4-path-tool** info [OPTIONS...] <PATH>
+
+DESCRIPTION
+-----------
+
+``gtk4-path-tool`` can perform various tasks on paths. Paths are specified
+in SVG syntax, as strings like "M 100 100 C 100 200 200 200 200 100 Z".
+
+To read a path from a file, use a filename that starts with a '.' or a '/'.
+To read a path from stdin, use '-'.
+
+COMMANDS
+--------
+
+Decomposing
+^^^^^^^^^^^
+
+The ``decompose`` command approximates the path by one with simpler elements.
+When used without options, the curves of the path are approximated by line
+segments.
+
+``--allow-curves``
+
+  Allow cubic Bézier curves to be used in the generated path.
+
+``--allow-conics``
+
+  Allow rational quadratic Bézier curves to be used in the generated path.
+
+Restricting
+^^^^^^^^^^^
+
+The ``restrict`` command creates a path that traces a segment of the original
+path. Note that the start and the end of the segment are specified as
+path length from the beginning of the path.
+
+``--start=LENGTH``
+
+  The distance from the beginning of the path where the segment begins. The
+  default values is 0.
+
+``--end=LENGTH``
+
+  The distance from the beginning of the path where the segment ends. The
+  default value is the length of path.
+
+Showing
+^^^^^^^
+
+The ``show`` command displays the given path in a window. The interior
+of the path is filled.
+
+``--fill-rule=VALUE``
+
+  The fill rule that is used to determine what areas are inside the path.
+  The possible values are ``winding`` or ``even-odd``. The default is ``winding``.
+
+``--fg-color=COLOR``
+
+  The color that is used to fill the interior of the path.
+  If not specified, black is used.
+
+``--bg-color=COLOR``
+
+  The color that is used to render the background behind the path.
+  If not specified, white is used.
+
+Rendering
+^^^^^^^^^
+
+The ``render`` command renders the given path as a PNG image.
+The interior of the path is filled.
+
+``--fill-rule=VALUE``
+
+  The fill rule that is used to determine what areas are inside the path.
+  The possible values are ``winding`` or ``even-odd``. The default is ``winding``.
+
+``--fg-color=COLOR``
+
+  The color that is used to fill the interior of the path.
+  If not specified, black is used.
+
+``--bg-color=COLOR``
+
+  The color that is used to render the background behind the path.
+  If not specified, white is used.
+
+``--output-file=FILE``
+
+  The file to save the PNG image to.
+  If not specified, "path.png" is used.
+
+Info
+^^^^
+
+The ``info`` command shows various information about the given path,
+such as its bounding box and and its length.
+
+REFERENCES
+----------
+
+- SVG Path Specification, https://www.w3.org/TR/SVG2/paths.html

docs/reference/gtk/meson.build

@@ -77,6 +77,7 @@ if get_option('man-pages') and rst2man.found()
     [ 'gtk4-query-settings', '1', ],
     [ 'gtk4-rendernode-tool', '1' ],
     [ 'gtk4-update-icon-cache', '1', ],
+    [ 'gtk4-path-tool', '1', ],
   ]
 
   if get_option('demos')

gsk/broadway/gskbroadwayrenderer.c

@@ -271,6 +271,8 @@ collect_reused_child_nodes (GskRenderer *renderer,
     case GSK_CROSS_FADE_NODE:
     case GSK_BLUR_NODE:
     case GSK_MASK_NODE:
+    case GSK_FILL_NODE:
+    case GSK_STROKE_NODE:
 
     default:
 
@@ -859,6 +861,8 @@ 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

@@ -255,6 +255,8 @@ node_supports_2d_transform (const GskRenderNode *node)
     case GSK_BLEND_NODE:
     case GSK_BLUR_NODE:
     case GSK_MASK_NODE:
+    case GSK_FILL_NODE:
+    case GSK_STROKE_NODE:
       return TRUE;
 
     case GSK_SHADOW_NODE:
@@ -309,6 +311,8 @@ node_supports_transform (const GskRenderNode *node)
     case GSK_BLEND_NODE:
     case GSK_BLUR_NODE:
     case GSK_MASK_NODE:
+    case GSK_FILL_NODE:
+    case GSK_STROKE_NODE:
       return TRUE;
 
     case GSK_SHADOW_NODE:
@@ -4089,6 +4093,14 @@ gsk_gl_render_job_visit_node (GskGLRenderJob      *job,
       gsk_gl_render_job_visit_as_fallback (job, node);
     break;
 
+    case GSK_FILL_NODE:
+      gsk_gl_render_job_visit_as_fallback (job, node);
+    break;
+
+    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.h

@@ -20,9 +20,14 @@
 #define __GSK_H_INSIDE__
 
 #include <gsk/gskenums.h>
+#include <gsk/gskpath.h>
+#include <gsk/gskpathbuilder.h>
+#include <gsk/gskpathmeasure.h>
+#include <gsk/gskpathpoint.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>
 

gsk/gskboundingboxprivate.h

@@ -0,0 +1,100 @@
+#pragma once
+
+#include <gsk/gsktypes.h>
+
+G_BEGIN_DECLS
+
+typedef struct _GskBoundingBox GskBoundingBox;
+
+struct _GskBoundingBox {
+  graphene_point_t min;
+  graphene_point_t max;
+};
+
+static inline 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;
+}
+
+static inline GskBoundingBox *
+gsk_bounding_box_init_copy (GskBoundingBox       *self,
+                            const GskBoundingBox *src)
+{
+  self->min = src->min;
+  self->max = src->max;
+  return self;
+}
+
+static inline 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;
+}
+
+static inline 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);
+}
+
+static inline 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;
+}
+
+static inline 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;
+}
+
+static inline gboolean
+gsk_bounding_box_contains_point_with_epsilon (const GskBoundingBox   *self,
+                                              const graphene_point_t *p,
+                                              float                   epsilon)
+{
+  return self->min.x - epsilon <= p->x && p->x <= self->max.x + epsilon &&
+         self->min.y - epsilon <= p->y && p->y <= self->max.y + epsilon;
+}
+
+static inline 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;
+}
+
+G_END_DECLS

gsk/gskcontourprivate.h

@@ -0,0 +1,107 @@
+/*
+ * 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>
+ */
+
+
+#pragma once
+
+#include "gskpathprivate.h"
+#include "gskpathpointprivate.h"
+#include "gskpathopprivate.h"
+
+G_BEGIN_DECLS
+
+GskContour *            gsk_rect_contour_new                    (const graphene_rect_t  *rect);
+GskContour *            gsk_rounded_rect_contour_new            (const GskRoundedRect   *rounded_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);
+gboolean                gsk_contour_get_stroke_bounds           (const GskContour       *self,
+                                                                 const GskStroke        *stroke,
+                                                                 graphene_rect_t        *bounds);
+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);
+int                     gsk_contour_get_winding                 (const GskContour       *self,
+                                                                 const graphene_point_t *point);
+
+gboolean                gsk_contour_get_closest_point           (const GskContour       *self,
+                                                                 const graphene_point_t *point,
+                                                                 float                   threshold,
+                                                                 GskRealPathPoint       *result,
+                                                                 float                  *out_dist);
+
+void                    gsk_contour_get_position                (const GskContour       *self,
+                                                                 GskRealPathPoint       *point,
+                                                                 graphene_point_t       *pos);
+
+void                    gsk_contour_get_tangent                 (const GskContour       *self,
+                                                                 GskRealPathPoint       *point,
+                                                                 GskPathDirection        direction,
+                                                                 graphene_vec2_t        *tangent);
+float                   gsk_contour_get_curvature               (const GskContour       *self,
+                                                                 GskRealPathPoint       *point,
+                                                                 graphene_point_t       *center);
+gpointer                gsk_contour_init_measure                (const GskContour       *self,
+                                                                 float                   tolerance,
+                                                                 float                  *out_length);
+void                    gsk_contour_free_measure                (const GskContour       *self,
+                                                                 gpointer                data);
+void                    gsk_contour_add_segment                 (const GskContour       *self,
+                                                                 GskPathBuilder         *builder,
+                                                                 gpointer                measure_data,
+                                                                 gboolean                emit_move_to,
+                                                                 float                   start,
+                                                                 float                   end);
+void                    gsk_contour_get_point                   (const GskContour       *self,
+                                                                 gpointer                measure_data,
+                                                                 float                   offset,
+                                                                 GskRealPathPoint       *result);
+float                   gsk_contour_get_distance                (const GskContour       *self,
+                                                                 GskRealPathPoint       *point,
+                                                                 gpointer                measure_data);
+gboolean                gsk_contour_dash                        (const GskContour       *contour,
+                                                                 GskStroke              *stroke,
+                                                                 float                   tolerance,
+                                                                 GskPathForeachFunc      func,
+                                                                 gpointer                user_data);
+
+G_END_DECLS

gsk/gskcurveprivate.h

@@ -0,0 +1,176 @@
+/*
+ * 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>
+ */
+
+
+#pragma once
+
+#include "gskpathopprivate.h"
+#include "gskpath.h"
+#include "gskboundingboxprivate.h"
+
+G_BEGIN_DECLS
+
+typedef gpointer gskpathop;
+
+typedef union _GskCurve GskCurve;
+
+typedef struct _GskLineCurve GskLineCurve;
+typedef struct _GskQuadCurve GskQuadCurve;
+typedef struct _GskCubicCurve GskCubicCurve;
+typedef struct _GskConicCurve GskConicCurve;
+
+struct _GskLineCurve
+{
+  GskPathOperation op;
+
+  gboolean padding;
+
+  graphene_point_t points[2];
+};
+
+struct _GskQuadCurve
+{
+  GskPathOperation op;
+
+  gboolean has_coefficients;
+
+  graphene_point_t points[3];
+
+  graphene_point_t coeffs[3];
+};
+
+struct _GskCubicCurve
+{
+  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;
+  GskQuadCurve quad;
+  GskCubicCurve cubic;
+  GskConicCurve conic;
+};
+
+typedef enum {
+  GSK_CURVE_LINE_REASON_STRAIGHT,
+  GSK_CURVE_LINE_REASON_SHORT
+} GskCurveLineReason;
+
+typedef gboolean (* GskCurveAddLineFunc) (const graphene_point_t *from,
+                                          const graphene_point_t *to,
+                                          float                   from_progress,
+                                          float                   to_progress,
+                                          GskCurveLineReason      reason,
+                                          gpointer                user_data);
+
+typedef gboolean (* GskCurveAddCurveFunc) (GskPathOperation        op,
+                                           const graphene_point_t *pts,
+                                           gsize                   n_pts,
+                                           float                   weight,
+                                           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_print                         (const GskCurve         *curve,
+                                                                 GString                *string);
+
+char *                  gsk_curve_to_string                     (const GskCurve         *curve);
+
+gskpathop               gsk_curve_pathop                        (const GskCurve         *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_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_reverse                       (const GskCurve         *curve,
+                                                                 GskCurve               *reverse);
+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,
+                                                                 GskPathForeachFlags     flags,
+                                                                 float                   tolerance,
+                                                                 GskCurveAddCurveFunc    add_curve_func,
+                                                                 gpointer                user_data);
+
+#define gsk_curve_builder_to(curve, builder) gsk_path_builder_pathop_to ((builder), gsk_curve_pathop (curve))
+
+float                   gsk_curve_get_curvature                 (const GskCurve         *curve,
+                                                                 float                   t,
+                                                                 graphene_point_t       *center);
+void                    gsk_curve_get_bounds                    (const GskCurve         *curve,
+                                                                 GskBoundingBox         *bounds);
+void                    gsk_curve_get_tight_bounds              (const GskCurve         *curve,
+                                                                 GskBoundingBox         *bounds);
+
+int                     gsk_curve_get_crossing                  (const GskCurve         *curve,
+                                                                 const graphene_point_t *point);
+gboolean                gsk_curve_get_closest_point             (const GskCurve         *curve,
+                                                                 const graphene_point_t *point,
+                                                                 float                   threshold,
+                                                                 float                  *out_dist,
+                                                                 float                  *out_t);
+
+G_END_DECLS
+

gsk/gskenums.h

@@ -42,6 +42,8 @@
  * @GSK_REPEAT_NODE: A node that repeats the child's contents
  * @GSK_CLIP_NODE: A node that clips its child to a rectangular area
  * @GSK_ROUNDED_CLIP_NODE: A node that clips its child to a rounded rectangle
+ * @GSK_FILL_NODE: A node that fills a path
+ * @GSK_STROKE_NODE: A node that strokes a path
  * @GSK_SHADOW_NODE: A node that draws a shadow below its child
  * @GSK_BLEND_NODE: A node that blends two children together
  * @GSK_CROSS_FADE_NODE: A node that cross-fades between two children
@@ -74,6 +76,8 @@ 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,
@@ -170,6 +174,136 @@ 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.
+ *
+ * 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.
+ *
+ * Since: 4.14
+ */
+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`.
+ *
+ * New entries may be added in future versions.
+ *
+ * Since: 4.14
+ */
+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 join point
+ * @GSK_LINE_JOIN_BEVEL: use a cut-off join, the join is cut off at half
+ *   the line width from the joint point
+ *
+ * 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`.
+ *
+ * New entries may be added in future versions.
+ *
+ * Since: 4.14
+ */
+typedef enum {
+  GSK_LINE_JOIN_MITER,
+  GSK_LINE_JOIN_MITER_CLIP,
+  GSK_LINE_JOIN_ROUND,
+  GSK_LINE_JOIN_BEVEL,
+} GskLineJoin;
+
+/**
+ * GskPathOperation:
+ * @GSK_PATH_MOVE: A move-to operation, with 1 point describing the target point.
+ * @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_LINE: A line-to operation, with 2 points describing the start and
+ *   end point of a straight line.
+ * @GSK_PATH_QUAD: A curve-to operation describing a quadratic Bézier curve
+ *   with 3 points describing the start point, the control point and the end
+ *   point of the curve.
+ * @GSK_PATH_CUBIC: 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 are used to described segments of a `GskPath`.
+ *
+ * More values may be added in the future.
+ *
+ * Since: 4.14
+ */
+typedef enum {
+  GSK_PATH_MOVE,
+  GSK_PATH_CLOSE,
+  GSK_PATH_LINE,
+  GSK_PATH_QUAD,
+  GSK_PATH_CUBIC,
+  GSK_PATH_CONIC,
+} GskPathOperation;
+
+/**
+ * GskPathDirection:
+ * @GSK_PATH_START: The side that leads to the start of the path
+ * @GSK_PATH_END: The side that leads to the end of the path
+ *
+ * The values of the `GskPathDirection` enum are used to pick one
+ * of the two sides of the path that at a given point on the path.
+ *
+ * Since: 4.14
+ */
+typedef enum {
+  GSK_PATH_START,
+  GSK_PATH_END
+} GskPathDirection;
+
 /**
  * GskSerializationError:
  * @GSK_SERIALIZATION_UNSUPPORTED_FORMAT: The format can not be identified
@@ -274,4 +408,3 @@ typedef enum
   GSK_MASK_MODE_LUMINANCE,
   GSK_MASK_MODE_INVERTED_LUMINANCE
 } GskMaskMode;
-

gsk/gskpath.h

@@ -0,0 +1,130 @@
+/*
+ * 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>
+ */
+
+#pragma once
+
+#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_QUAD: Allow emission of `GSK_PATH_QUAD` operations
+ * @GSK_PATH_FOREACH_ALLOW_CUBIC: Allow emission of `GSK_PATH_CUBIC` operations.
+ * @GSK_PATH_FOREACH_ALLOW_CONIC: Allow emission of `GSK_PATH_CONIC` operations.
+ *
+ * Flags that can be passed to 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_QUAD  = (1 << 0),
+  GSK_PATH_FOREACH_ALLOW_CUBIC = (1 << 1),
+  GSK_PATH_FOREACH_ALLOW_CONIC = (1 << 2),
+} 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_4_14
+GType                   gsk_path_get_type                       (void) G_GNUC_CONST;
+
+GDK_AVAILABLE_IN_4_14
+GskPath *               gsk_path_ref                            (GskPath                *self);
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_unref                          (GskPath                *self);
+
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_print                          (GskPath                *self,
+                                                                 GString                *string);
+GDK_AVAILABLE_IN_4_14
+char *                  gsk_path_to_string                      (GskPath                *self);
+
+GDK_AVAILABLE_IN_4_14
+GskPath *               gsk_path_parse                          (const char             *string);
+
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_to_cairo                       (GskPath                *self,
+                                                                 cairo_t                *cr);
+
+GDK_AVAILABLE_IN_4_14
+gboolean                gsk_path_is_empty                       (GskPath                *self);
+
+GDK_AVAILABLE_IN_4_14
+gboolean                gsk_path_is_closed                      (GskPath                *self);
+
+GDK_AVAILABLE_IN_4_14
+gboolean                gsk_path_get_bounds                     (GskPath                *self,
+                                                                 graphene_rect_t        *bounds);
+
+GDK_AVAILABLE_IN_4_14
+gboolean                gsk_path_in_fill                        (GskPath                *self,
+                                                                 const graphene_point_t *point,
+                                                                 GskFillRule             fill_rule);
+
+GDK_AVAILABLE_IN_4_14
+gboolean                gsk_path_get_closest_point              (GskPath                *self,
+                                                                 const graphene_point_t *point,
+                                                                 float                   threshold,
+                                                                 GskPathPoint           *result);
+
+GDK_AVAILABLE_IN_4_14
+gboolean                gsk_path_foreach                        (GskPath                *self,
+                                                                 GskPathForeachFlags     flags,
+                                                                 GskPathForeachFunc      func,
+                                                                 gpointer                user_data);
+
+GDK_AVAILABLE_IN_4_14
+gboolean                gsk_path_dash                           (GskPath                *self,
+                                                                 GskStroke              *stroke,
+                                                                 float                   tolerance,
+                                                                 GskPathForeachFunc      func,
+                                                                 gpointer                user_data);
+
+G_DEFINE_AUTOPTR_CLEANUP_FUNC(GskPath, gsk_path_unref)
+
+G_END_DECLS

gsk/gskpathbuilder.h

@@ -0,0 +1,147 @@
+/*
+ * 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>
+ */
+
+#pragma once
+
+#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_4_14
+GType                   gsk_path_builder_get_type               (void) G_GNUC_CONST;
+
+GDK_AVAILABLE_IN_4_14
+GskPathBuilder *        gsk_path_builder_new                    (void);
+GDK_AVAILABLE_IN_4_14
+GskPathBuilder *        gsk_path_builder_ref                    (GskPathBuilder         *self);
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_builder_unref                  (GskPathBuilder         *self);
+GDK_AVAILABLE_IN_4_14
+GskPath *               gsk_path_builder_free_to_path           (GskPathBuilder         *self) G_GNUC_WARN_UNUSED_RESULT;
+GDK_AVAILABLE_IN_4_14
+GskPath *               gsk_path_builder_to_path                (GskPathBuilder         *self) G_GNUC_WARN_UNUSED_RESULT;
+
+GDK_AVAILABLE_IN_4_14
+const graphene_point_t *gsk_path_builder_get_current_point      (GskPathBuilder         *self);
+
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_builder_add_path               (GskPathBuilder         *self,
+                                                                 GskPath                *path);
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_builder_add_reverse_path       (GskPathBuilder         *self,
+                                                                 GskPath                *path);
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_builder_add_cairo_path         (GskPathBuilder         *self,
+                                                                 const cairo_path_t     *path);
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_builder_add_layout             (GskPathBuilder         *self,
+                                                                 PangoLayout            *layout);
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_builder_add_rect               (GskPathBuilder         *self,
+                                                                 const graphene_rect_t  *rect);
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_builder_add_rounded_rect       (GskPathBuilder         *self,
+                                                                 const GskRoundedRect   *rect);
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_builder_add_circle             (GskPathBuilder         *self,
+                                                                 const graphene_point_t *center,
+                                                                 float                   radius);
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_builder_add_ellipse            (GskPathBuilder         *self,
+                                                                 const graphene_point_t *center,
+                                                                 const graphene_size_t  *radius);
+
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_builder_add_segment            (GskPathBuilder         *self,
+                                                                 GskPathMeasure         *measure,
+                                                                 float                   start,
+                                                                 float                   end);
+
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_builder_move_to                (GskPathBuilder         *self,
+                                                                 float                   x,
+                                                                 float                   y);
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_builder_rel_move_to            (GskPathBuilder         *self,
+                                                                 float                   x,
+                                                                 float                   y);
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_builder_line_to                (GskPathBuilder         *self,
+                                                                 float                   x,
+                                                                 float                   y);
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_builder_rel_line_to            (GskPathBuilder         *self,
+                                                                 float                   x,
+                                                                 float                   y);
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_builder_quad_to                (GskPathBuilder         *self,
+                                                                 float                   x1,
+                                                                 float                   y1,
+                                                                 float                   x2,
+                                                                 float                   y2);
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_builder_rel_quad_to            (GskPathBuilder         *self,
+                                                                 float                   x1,
+                                                                 float                   y1,
+                                                                 float                   x2,
+                                                                 float                   y2);
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_builder_cubic_to               (GskPathBuilder         *self,
+                                                                 float                   x1,
+                                                                 float                   y1,
+                                                                 float                   x2,
+                                                                 float                   y2,
+                                                                 float                   x3,
+                                                                 float                   y3);
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_builder_rel_cubic_to           (GskPathBuilder         *self,
+                                                                 float                   x1,
+                                                                 float                   y1,
+                                                                 float                   x2,
+                                                                 float                   y2,
+                                                                 float                   x3,
+                                                                 float                   y3);
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_builder_conic_to               (GskPathBuilder         *self,
+                                                                 float                   x1,
+                                                                 float                   y1,
+                                                                 float                   x2,
+                                                                 float                   y2,
+                                                                 float                   weight);
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_builder_rel_conic_to           (GskPathBuilder         *self,
+                                                                 float                   x1,
+                                                                 float                   y1,
+                                                                 float                   x2,
+                                                                 float                   y2,
+                                                                 float                   weight);
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_builder_close                  (GskPathBuilder         *self);
+
+G_DEFINE_AUTOPTR_CLEANUP_FUNC(GskPathBuilder, gsk_path_builder_unref)
+
+G_END_DECLS

gsk/gskpathdash.c

@@ -0,0 +1,306 @@
+/*
+ * 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 "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,
+                                GskCurveLineReason      reason,
+                                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_QUAD:
+    case GSK_PATH_CUBIC:
+    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;
+}
+
+/**
+ * gsk_path_dash:
+ * @self: the `GskPath` to dash
+ * @stroke: the stroke containing the dash parameters
+ * @tolerance: tolerance to use while dashing
+ * @func: (scope call) (closure user_data): the function to call for operations
+ * @user_data: (nullable): user data passed to @func
+ *
+ * Calls @func for every operation of the path that is the result
+ * of dashing @self with the dash pattern from @stroke.
+ *
+ * Returns: `FALSE` if @func returned FALSE`, `TRUE` otherwise.
+ *
+ * Since: 4.14
+ */
+gboolean
+gsk_path_dash (GskPath            *self,
+               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 (self, -1, func, user_data);
+
+  for (i = 0; i < gsk_path_get_n_contours (self); i++)
+    {
+      if (!gsk_contour_dash (gsk_path_get_contour (self, i), stroke, tolerance, func, user_data))
+        return FALSE;
+    }
+
+  return TRUE;
+}
+

gsk/gskpathmeasure.c

@@ -0,0 +1,411 @@
+/*
+ * 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 "gskpathpointprivate.h"
+#include "gskpathprivate.h"
+
+/**
+ * GskPathMeasure:
+ *
+ * `GskPathMeasure` is an object that allows measurements
+ * on `GskPath`s such as determining the length of the path.
+ *
+ * Many measuring operations require approximating the path
+ * with simpler shapes. Therefore, a `GskPathMeasure` has
+ * a tolerance that determines what precision is required
+ * for such approximations.
+ *
+ * A `GskPathMeasure` struct is a reference counted struct
+ * and should be treated as opaque.
+ */
+
+typedef struct _GskContourMeasure GskContourMeasure;
+
+struct _GskContourMeasure
+{
+  float length;
+  gpointer contour_data;
+};
+
+struct _GskPathMeasure
+{
+  /*< private >*/
+  guint ref_count;
+
+  GskPath *path;
+  float tolerance;
+
+  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.
+ *
+ * Returns: a new `GskPathMeasure` representing @path
+ *
+ * Since: 4.14
+ */
+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
+ *
+ * Since: 4.14
+ */
+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;
+
+  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`.
+ *
+ * Since: 4.14
+ */
+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.
+ *
+ * Since: 4.14
+ */
+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
+ *
+ * Since: 4.14
+ */
+GskPath *
+gsk_path_measure_get_path (GskPathMeasure *self)
+{
+  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
+ *
+ * Since: 4.14
+ */
+float
+gsk_path_measure_get_tolerance (GskPathMeasure *self)
+{
+  return self->tolerance;
+}
+
+/**
+ * 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
+ *
+ * Since: 4.14
+ */
+float
+gsk_path_measure_get_length (GskPathMeasure *self)
+{
+  g_return_val_if_fail (self != NULL, 0);
+
+  return self->length;
+}
+
+static float
+gsk_path_measure_clamp_distance (GskPathMeasure *self,
+                                 float           distance)
+{
+  if (isnan (distance))
+    return 0;
+
+  return CLAMP (distance, 0, self->length);
+}
+
+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 = 0; i < measure->n_contours; 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:
+ * @self: a `GskPathBuilder`
+ * @measure: the `GskPathMeasure` to take the segment to
+ * @start: start distance into the path
+ * @end: end distance into the path
+ *
+ * Adds to @self 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 its length for the end
+ * of the path. The values will be clamped to that range. The length
+ * can be obtained with [method@Gsk.PathMeasure.get_length].
+ *
+ * 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.
+ *
+ * Since: 4.14
+ */
+void
+gsk_path_builder_add_segment (GskPathBuilder *self,
+                              GskPathMeasure *measure,
+                              float           start,
+                              float           end)
+{
+  g_return_if_fail (self != 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 (self, measure, TRUE, start, end);
+    }
+  else
+    {
+      /* If the path is closed, we can connect the 2 subpaths. */
+      gboolean closed = gsk_path_is_closed (measure->path);
+      gboolean need_move_to = !closed;
+
+      if (start < measure->length)
+        gsk_path_builder_add_segment_chunk (self, measure,
+                                            TRUE,
+                                            start, measure->length);
+      else
+        need_move_to = TRUE;
+
+      if (end > 0)
+        gsk_path_builder_add_segment_chunk (self, measure,
+                                            need_move_to,
+                                            0, end);
+      if (start == end && closed)
+        gsk_path_builder_close (self);
+    }
+}
+
+/**
+ * gsk_path_measure_get_point:
+ * @self: a `GskPathMeasure`
+ * @distance: the distance
+ * @result: (out caller-allocates): return location for the result
+ *
+ * Sets @result to the point at the given distance into the path.
+ *
+ * An empty path has no points, so `FALSE` is returned in that case.
+ *
+ * Returns: `TRUE` if @result was set
+ *
+ * Since: 4.14
+ */
+gboolean
+gsk_path_measure_get_point (GskPathMeasure *self,
+                            float           distance,
+                            GskPathPoint   *result)
+{
+  GskRealPathPoint *res = (GskRealPathPoint *) result;
+  gsize i;
+  float offset;
+  const GskContour *contour;
+
+  g_return_val_if_fail (self != NULL, FALSE);
+  g_return_val_if_fail (result != NULL, FALSE);
+
+  if (self->n_contours == 0)
+    return FALSE;
+
+  offset = gsk_path_measure_clamp_distance (self, distance);
+
+  for (i = 0; i < self->n_contours - 1; i++)
+    {
+      if (offset < self->measures[i].length)
+        break;
+
+      offset -= self->measures[i].length;
+    }
+
+  g_assert (0 <= i && i < self->n_contours);
+
+  offset = CLAMP (offset, 0, self->measures[i].length);
+
+  contour = gsk_path_get_contour (self->path, i);
+
+  gsk_contour_get_point (contour, self->measures[i].contour_data, offset, res);
+
+  return TRUE;
+}
+
+float
+gsk_path_measure_get_distance (GskPathMeasure *self,
+                               GskPathPoint   *point)
+{
+  GskRealPathPoint *p = (GskRealPathPoint *)point;
+  const GskContour *contour = p->contour;
+  float contour_offset = 0;
+
+  g_return_val_if_fail (self != NULL, 0);
+  g_return_val_if_fail (point != NULL, 0);
+  g_return_val_if_fail (self->path == p->path, 0);
+
+  for (gsize i = 0; i < self->n_contours; i++)
+    {
+      if (contour == gsk_path_get_contour (self->path, i))
+        return contour_offset + gsk_contour_get_distance (contour,
+                                                          p,
+                                                          self->measures[i].contour_data);
+
+      contour_offset += self->measures[i].length;
+    }
+
+  g_return_val_if_reached (0);
+}

gsk/gskpathmeasure.h

@@ -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>
+ */
+
+#pragma once
+
+#if !defined (__GSK_H_INSIDE__) && !defined (GTK_COMPILATION)
+#error "Only <gsk/gsk.h> can be included directly."
+#endif
+
+
+#include <gsk/gskpath.h>
+#include <gsk/gskpathpoint.h>
+
+G_BEGIN_DECLS
+
+#define GSK_TYPE_PATH_MEASURE (gsk_path_measure_get_type ())
+
+GDK_AVAILABLE_IN_4_14
+GType                   gsk_path_measure_get_type               (void) G_GNUC_CONST;
+GDK_AVAILABLE_IN_4_14
+GskPathMeasure *        gsk_path_measure_new                    (GskPath                *path);
+GDK_AVAILABLE_IN_4_14
+GskPathMeasure *        gsk_path_measure_new_with_tolerance     (GskPath                *path,
+                                                                 float                   tolerance);
+
+GDK_AVAILABLE_IN_4_14
+GskPathMeasure *        gsk_path_measure_ref                    (GskPathMeasure         *self);
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_measure_unref                  (GskPathMeasure         *self);
+
+GDK_AVAILABLE_IN_4_14
+GskPath *               gsk_path_measure_get_path               (GskPathMeasure         *self) G_GNUC_PURE;
+GDK_AVAILABLE_IN_4_14
+float                   gsk_path_measure_get_tolerance          (GskPathMeasure         *self) G_GNUC_PURE;
+
+GDK_AVAILABLE_IN_4_14
+float                   gsk_path_measure_get_length             (GskPathMeasure         *self);
+
+GDK_AVAILABLE_IN_4_14
+gboolean                gsk_path_measure_get_point              (GskPathMeasure         *self,
+                                                                 float                   distance,
+                                                                 GskPathPoint           *point);
+
+GDK_AVAILABLE_IN_4_14
+float                   gsk_path_measure_get_distance           (GskPathMeasure         *self,
+                                                                 GskPathPoint           *point);
+
+G_DEFINE_AUTOPTR_CLEANUP_FUNC(GskPathMeasure, gsk_path_measure_unref)
+
+G_END_DECLS

gsk/gskpathopprivate.h

@@ -0,0 +1,186 @@
+/*
+ * 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>
+ */
+
+
+#pragma once
+
+#include "gskpath.h"
+#include "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_QUAD:
+      return func (gsk_pathop_op (pop), gsk_pathop_points (pop), 3, 0, user_data);
+
+    case GSK_PATH_CUBIC:
+      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_QUAD:
+      gsk_path_builder_quad_to (builder, pts[1].x, pts[1].y, pts[2].x, pts[2].y);
+      break;
+
+    case GSK_PATH_CUBIC:
+      gsk_path_builder_cubic_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_QUAD:
+      gsk_path_builder_quad_to (builder, pts[1].x, pts[1].y, pts[0].x, pts[0].y);
+      break;
+
+    case GSK_PATH_CUBIC:
+      gsk_path_builder_cubic_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

gsk/gskpathpoint.c

@@ -0,0 +1,165 @@
+/*
+ * Copyright © 2023 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 "gskpathpointprivate.h"
+
+#include "gskcontourprivate.h"
+#include "gskpathmeasure.h"
+
+#include "gdk/gdkprivate.h"
+
+
+/**
+ * GskPathPoint:
+ *
+ * `GskPathPoint` is an opaque type representing a point on a path.
+ *
+ * It can be queried for properties of the path at that point, such as its
+ * tangent or its curvature.
+ *
+ * To obtain a `GskPathPoint`, use [method@Gsk.Path.get_closest_point]
+ * or [method@Gsk.PathMeasure.get_point].
+ *
+ * Note that `GskPathPoint` structs are meant to be stack-allocated, and
+ * don't a reference to the path object they are obtained from. It is the
+ * callers responsibility to keep a reference to the path as long as the
+ * `GskPathPoint` is used.
+ */
+
+G_DEFINE_BOXED_TYPE (GskPathPoint, gsk_path_point,
+                     gsk_path_point_copy,
+                     gsk_path_point_free)
+
+
+GskPathPoint *
+gsk_path_point_copy (GskPathPoint *point)
+{
+  GskPathPoint *copy;
+
+  copy = g_new0 (GskPathPoint, 1);
+
+  memcpy (copy, point, sizeof (GskRealPathPoint));
+
+  return copy;
+}
+
+void
+gsk_path_point_free (GskPathPoint *point)
+{
+  g_free (point);
+}
+
+GskPath *
+gsk_path_point_get_path (GskPathPoint *point)
+{
+  GskRealPathPoint *self = (GskRealPathPoint *) point;
+
+  return self->path;
+}
+
+const GskContour *
+gsk_path_point_get_contour (GskPathPoint *point)
+{
+  GskRealPathPoint *self = (GskRealPathPoint *) point;
+
+  return self->contour;
+}
+
+/**
+ * gsk_path_point_get_position:
+ * @point: a `GskPathPoint`
+ * @position: (out caller-allocates): Return location for
+ *   the coordinates of the point
+ *
+ * Gets the position of the point.
+ *
+ * Since: 4.14
+ */
+void
+gsk_path_point_get_position (GskPathPoint     *point,
+                             graphene_point_t *position)
+{
+  GskRealPathPoint *self = (GskRealPathPoint *) point;
+
+  gsk_contour_get_position (self->contour, self, position);
+}
+
+/**
+ * gsk_path_point_get_tangent:
+ * @point: a `GskPathPoint`
+ * @direction: the direction for which to return the tangent
+ * @tangent: (out caller-allocates): Return location for
+ *   the tangent at the point
+ *
+ * Gets the tangent of the path at the point.
+ *
+ * Note that certain points on a path may not have a single
+ * tangent, such as sharp turns. At such points, there are
+ * two tangents -- the direction of the path going into the
+ * point, and the direction coming out of it. The @direction
+ * argument lets you choose which one to get.
+ *
+ * Since: 4.14
+ */
+void
+gsk_path_point_get_tangent (GskPathPoint     *point,
+                            GskPathDirection  direction,
+                            graphene_vec2_t  *tangent)
+{
+  GskRealPathPoint *self = (GskRealPathPoint *) point;
+
+  gsk_contour_get_tangent (self->contour, self, direction, tangent);
+}
+
+/**
+ * gsk_path_point_get_curvature:
+ * @point: a `GskPathPoint`
+ * @center: (out caller-allocates): Return location for
+ *   the center of the osculating circle
+ *
+ * Calculates the curvature of the path at the point.
+ *
+ * Optionally, returns the center of the osculating circle as well.
+ *
+ * If the curvature is infinite (at line segments), zero is returned,
+ * and @center is not modified.
+ *
+ * Returns: The curvature of the path at the given point
+ *
+ * Since: 4.14
+ */
+float
+gsk_path_point_get_curvature (GskPathPoint     *point,
+                              graphene_point_t *center)
+{
+  GskRealPathPoint *self = (GskRealPathPoint *) point;
+
+  return gsk_contour_get_curvature (self->contour, self, center);
+}
+
+float
+gsk_path_point_get_distance (GskPathPoint *point,
+                             gpointer      measure_data)
+{
+  GskRealPathPoint *self = (GskRealPathPoint *) point;
+
+  return gsk_contour_get_distance (self->contour, self, measure_data);
+}

gsk/gskpathpoint.h

@@ -0,0 +1,64 @@
+/*
+ * Copyright © 2023 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>
+ */
+
+#pragma once
+
+#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_PATH_POINT (gsk_path_point_get_type ())
+
+typedef struct _GskPathPoint GskPathPoint;
+struct _GskPathPoint {
+  /*< private >*/
+  union {
+    float f[8];
+    gpointer p[8];
+  } data;
+};
+
+GDK_AVAILABLE_IN_4_14
+GType                   gsk_path_point_get_type        (void) G_GNUC_CONST;
+
+GDK_AVAILABLE_IN_4_14
+GskPathPoint *          gsk_path_point_copy            (GskPathPoint     *point);
+
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_point_free            (GskPathPoint     *point);
+
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_point_get_position    (GskPathPoint     *point,
+                                                        graphene_point_t *position);
+
+GDK_AVAILABLE_IN_4_14
+void                    gsk_path_point_get_tangent     (GskPathPoint     *point,
+                                                        GskPathDirection  direction,
+                                                        graphene_vec2_t  *tangent);
+
+GDK_AVAILABLE_IN_4_14
+float                   gsk_path_point_get_curvature   (GskPathPoint     *point,
+                                                        graphene_point_t *center);
+
+G_END_DECLS

gsk/gskpathpointprivate.h

@@ -0,0 +1,33 @@
+#pragma once
+
+#include "gskpathpoint.h"
+#include "gskcontourprivate.h"
+
+G_BEGIN_DECLS
+
+struct _GskRealPathPoint
+{
+  GskPath *path;
+  const GskContour *contour;
+
+  union {
+    struct {
+      unsigned int idx;
+      float t;
+    } std;
+    struct {
+      float distance;
+    } rect;
+    struct {
+      float angle;
+    } circle;
+  } data;
+};
+
+GskPath          * gsk_path_point_get_path     (GskPathPoint     *self);
+const GskContour * gsk_path_point_get_contour  (GskPathPoint     *self);
+float              gsk_path_point_get_distance (GskPathPoint     *self,
+                                                gpointer          measure_data);
+
+G_END_DECLS
+

gsk/gskpathprivate.h

@@ -0,0 +1,73 @@
+/*
+ * 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>
+ */
+
+
+#pragma once
+
+#include "gskpath.h"
+
+#include "gskpathopprivate.h"
+
+G_BEGIN_DECLS
+
+typedef enum
+{
+  GSK_PATH_FLAT,
+  GSK_PATH_CLOSED
+} GskPathFlags;
+
+typedef struct _GskContour GskContour;
+typedef struct _GskRealPathPoint GskRealPathPoint;
+
+/* 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);
+
+gboolean                gsk_path_get_stroke_bounds              (GskPath                *self,
+                                                                 const GskStroke        *stroke,
+                                                                 graphene_rect_t        *bounds);
+
+G_END_DECLS
+

gsk/gskpointprivate.h

@@ -0,0 +1,20 @@
+#pragma once
+
+#include <graphene.h>
+
+static inline void G_GNUC_PURE
+gsk_point_interpolate (const graphene_point_t *p1,
+                       const graphene_point_t *p2,
+                       float t,
+                       graphene_point_t *p)
+{
+  p->x = p1->x * (1 - t) + p2->x * t;
+  p->Y = p1->y * (1 - t) + p2->y * t;
+}
+
+static inline float G_GNUC_PURE
+gsk_point_distance (const graphene_point_t *p1,
+                    const graphene_point_t *p2)
+{
+  return sqrtf ((p1->x - p2->x)*(p1->x - p2->x) + (p1->y - p2->y)*(p1->y - p2->y));
+}

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())
@@ -186,6 +188,8 @@ 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;
@@ -459,6 +463,32 @@ 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_4_14
+GType                   gsk_fill_node_get_type                  (void) G_GNUC_CONST;
+GDK_AVAILABLE_IN_4_14
+GskRenderNode *         gsk_fill_node_new                       (GskRenderNode            *child,
+                                                                 GskPath                  *path,
+                                                                 GskFillRule               fill_rule);
+GDK_AVAILABLE_IN_4_14
+GskRenderNode *         gsk_fill_node_get_child                 (const GskRenderNode      *node);
+GDK_AVAILABLE_IN_4_14
+GskPath *               gsk_fill_node_get_path                  (const GskRenderNode      *node);
+GDK_AVAILABLE_IN_4_14
+GskFillRule             gsk_fill_node_get_fill_rule             (const GskRenderNode      *node);
+
+GDK_AVAILABLE_IN_4_14
+GType                   gsk_stroke_node_get_type                (void) G_GNUC_CONST;
+GDK_AVAILABLE_IN_4_14
+GskRenderNode *         gsk_stroke_node_new                     (GskRenderNode            *child,
+                                                                 GskPath                  *path,
+                                                                 const GskStroke          *stroke);
+GDK_AVAILABLE_IN_4_14
+GskRenderNode *         gsk_stroke_node_get_child               (const GskRenderNode      *node);
+GDK_AVAILABLE_IN_4_14
+GskPath *               gsk_stroke_node_get_path                (const GskRenderNode      *node);
+GDK_AVAILABLE_IN_4_14
+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

@@ -25,8 +25,10 @@
 #include "gskdebugprivate.h"
 #include "gskdiffprivate.h"
 #include "gl/gskglrenderer.h"
+#include "gskpathprivate.h"
 #include "gskrendererprivate.h"
 #include "gskroundedrectprivate.h"
+#include "gskstrokeprivate.h"
 #include "gsktransformprivate.h"
 
 #include "gdk/gdktextureprivate.h"
@@ -4366,6 +4368,387 @@ 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);
+    }
+}
+
+static void
+gsk_fill_node_class_init (gpointer g_class,
+                          gpointer class_data)
+{
+  GskRenderNodeClass *node_class = g_class;
+
+  node_class->node_type = GSK_FILL_NODE;
+
+  node_class->finalize = gsk_fill_node_finalize;
+  node_class->draw = gsk_fill_node_draw;
+  node_class->diff = gsk_fill_node_diff;
+}
+
+/**
+ * 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`
+ *
+ * Since: 4.14
+ */
+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
+ *
+ * Since: 4.14
+ */
+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`
+ *
+ * Retrieves the path used to describe the area filled with the contents of
+ * the @node.
+ *
+ * Returns: (transfer none): a `GskPath`
+ *
+ * Since: 4.14
+ */
+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`
+ *
+ * Retrieves the fill rule used to determine how the path is filled.
+ *
+ * Returns: a `GskFillRule`
+ *
+ * Since: 4.14
+ */
+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);
+    }
+}
+
+static void
+gsk_stroke_node_class_init (gpointer g_class,
+                            gpointer class_data)
+{
+  GskRenderNodeClass *node_class = g_class;
+
+  node_class->node_type = GSK_STROKE_NODE;
+
+  node_class->finalize = gsk_stroke_node_finalize;
+  node_class->draw = gsk_stroke_node_draw;
+  node_class->diff = gsk_stroke_node_diff;
+}
+
+/**
+ * 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
+ *
+ * Since: 4.14
+ */
+GskRenderNode *
+gsk_stroke_node_new (GskRenderNode   *child,
+                     GskPath         *path,
+                     const GskStroke *stroke)
+{
+  GskStrokeNode *self;
+  GskRenderNode *node;
+  graphene_rect_t stroke_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 (self->path, &self->stroke, &stroke_bounds))
+    graphene_rect_intersection (&stroke_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
+ *
+ * Since: 4.14
+ */
+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
+ *
+ * Retrieves the path that will be stroked with the contents of
+ * the @node.
+ *
+ * Returns: (transfer none): a #GskPath
+ *
+ * Since: 4.14
+ */
+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
+ *
+ * Retrieves the stroke attributes used in this @node.
+ *
+ * Returns: a #GskStroke
+ *
+ * Since: 4.14
+ */
+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 */
 
@@ -6259,6 +6642,8 @@ 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)
@@ -6407,6 +6792,16 @@ gsk_render_node_init_types_once (void)
                                                     sizeof (GskDebugNode),
                                                     gsk_debug_node_class_init);
   gsk_render_node_types[GSK_DEBUG_NODE] = node_type;
+
+  node_type = gsk_render_node_type_register_static (I_("GskFillNode"),
+                                                    sizeof (GskFillNode),
+                                                    gsk_fill_node_class_init);
+  gsk_render_node_types[GSK_FILL_NODE] = node_type;
+
+  node_type = gsk_render_node_type_register_static (I_("GskStrokeNode"),
+                                                    sizeof (GskStrokeNode),
+                                                    gsk_stroke_node_class_init);
+  gsk_render_node_types[GSK_STROKE_NODE] = node_type;
 }
 
 static void

gsk/gskrendernodeparser.c

@@ -23,8 +23,10 @@
 
 #include "gskrendernodeparserprivate.h"
 
+#include "gskpath.h"
 #include "gskroundedrectprivate.h"
 #include "gskrendernodeprivate.h"
+#include "gskstroke.h"
 #include "gsktransformprivate.h"
 
 #include "gdk/gdkrgbaprivate.h"
@@ -2433,6 +2435,14 @@ printer_init_duplicates_for_node (Printer       *printer,
       printer_init_duplicates_for_node (printer, gsk_debug_node_get_child (node));
       break;
 
+    case GSK_FILL_NODE:
+      printer_init_duplicates_for_node (printer, gsk_fill_node_get_child (node));
+      break;
+
+    case GSK_STROKE_NODE:
+      printer_init_duplicates_for_node (printer, gsk_stroke_node_get_child (node));
+      break;
+
     case GSK_BLEND_NODE:
       printer_init_duplicates_for_node (printer, gsk_blend_node_get_bottom_child (node));
       printer_init_duplicates_for_node (printer, gsk_blend_node_get_top_child (node));
@@ -2658,7 +2668,7 @@ 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;
 
@@ -3204,6 +3214,39 @@ 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:
+      {
+        char *path_str;
+
+        start_node (p, "fill", node_name);
+
+        append_node_param (p, "child", gsk_fill_node_get_child (node));
+        path_str = gsk_path_to_string (gsk_fill_node_get_path (node));
+        append_string_param (p, "path", path_str);
+        g_free (path_str);
+
+        end_node (p);
+      }
+      break;
+
+    case GSK_STROKE_NODE:
+      {
+        const GskStroke *stroke;
+        char *path_str;
+
+        start_node (p, "stroke", node_name);
+
+        append_node_param (p, "child", gsk_stroke_node_get_child (node));
+        path_str = gsk_path_to_string (gsk_stroke_node_get_path (node));
+        append_string_param (p, "path", path_str);
+        g_free (path_str);
+
+        stroke = gsk_stroke_node_get_stroke (node);
+        append_float_param (p, "line-width", gsk_stroke_get_line_width (stroke), 0.0);
 
         end_node (p);
       }

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 +1,479 @@
+/*
+ * 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` struct collects the parameters that influence
+ * the operation of 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`
+ *
+ * Since: 4.14
+ */
+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
+ *
+ * Since: 4.14
+ */
+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`.
+ *
+ * Since: 4.14
+ */
+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.
+ *
+ * Since: 4.14
+ */
+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:
+        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 2 strokes are identical.
+ *
+ * Returns: `TRUE` if the 2 strokes are equal, `FALSE` otherwise
+ *
+ * Since: 4.14
+ */
+gboolean
+gsk_stroke_equal (gconstpointer stroke1,
+                  gconstpointer stroke2)
+{
+  const GskStroke *self1 = stroke1;
+  const GskStroke *self2 = stroke2;
+
+  return self1->line_width == self2->line_width;
+}
+
+/**
+ * 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.
+ *
+ * Since: 4.14
+ */
+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
+ *
+ * Since: 4.14
+ */
+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 [enum@Gsk.LineCap] for details.
+ *
+ * Since: 4.14
+ */
+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 [enum@Gsk.LineCap] for details.
+ *
+ * Returns: The line cap
+ *
+ * Since: 4.14
+ */
+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 [enum@Gsk.LineJoin] for details.
+ *
+ * Since: 4.14
+ */
+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 [enum@Gsk.LineJoin] for details.
+ *
+ * Returns: The line join
+ *
+ * Since: 4.14
+ */
+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
+ *
+ * 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 and must be non-negative.
+ *
+ * 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.
+ *
+ * Since: 4.14
+ */
+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`.
+ *
+ * Since: 4.14
+ */
+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) (nullable):
+ *     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].
+ *
+ * Since: 4.14
+ */
+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) (nullable):
+ *   The dash array or `NULL` if the dash array is empty.
+ *
+ * Since: 4.14
+ */
+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 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.
+ *
+ * See [method@Gsk.Stroke.set_dash] for more details on dashing.
+ *
+ * Since: 4.14
+ */
+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`.
+ *
+ * Since: 4.14
+ */
+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 +1,87 @@
+/*
+ * 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>
+ */
+
+#pragma once
+
+#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_4_14
+GType                   gsk_stroke_get_type                     (void) G_GNUC_CONST;
+GDK_AVAILABLE_IN_4_14
+GskStroke *             gsk_stroke_new                          (float                   line_width);
+GDK_AVAILABLE_IN_4_14
+GskStroke *             gsk_stroke_copy                         (const GskStroke        *other);
+GDK_AVAILABLE_IN_4_14
+void                    gsk_stroke_free                         (GskStroke              *self);
+
+GDK_AVAILABLE_IN_4_14
+gboolean                gsk_stroke_equal                        (gconstpointer           stroke1,
+                                                                 gconstpointer           stroke2);
+
+GDK_AVAILABLE_IN_4_14
+void                    gsk_stroke_set_line_width               (GskStroke              *self,
+                                                                 float                   line_width);
+GDK_AVAILABLE_IN_4_14
+float                   gsk_stroke_get_line_width               (const GskStroke        *self);
+GDK_AVAILABLE_IN_4_14
+void                    gsk_stroke_set_line_cap                 (GskStroke              *self,
+                                                                 GskLineCap              line_cap);
+GDK_AVAILABLE_IN_4_14
+GskLineCap              gsk_stroke_get_line_cap                 (const GskStroke        *self);
+GDK_AVAILABLE_IN_4_14
+void                    gsk_stroke_set_line_join                (GskStroke              *self,
+                                                                 GskLineJoin             line_join);
+GDK_AVAILABLE_IN_4_14
+GskLineJoin             gsk_stroke_get_line_join                (const GskStroke        *self);
+
+GDK_AVAILABLE_IN_4_14
+void                    gsk_stroke_set_miter_limit              (GskStroke              *self,
+                                                                 float                   limit);
+GDK_AVAILABLE_IN_4_14
+float                   gsk_stroke_get_miter_limit              (const GskStroke        *self);
+
+GDK_AVAILABLE_IN_4_14
+void                    gsk_stroke_set_dash                     (GskStroke              *self,
+                                                                 const float            *dash,
+                                                                 gsize                   n_dash);
+GDK_AVAILABLE_IN_4_14
+const float *           gsk_stroke_get_dash                     (const GskStroke        *self,
+                                                                 gsize                  *n_dash);
+
+GDK_AVAILABLE_IN_4_14
+void                    gsk_stroke_set_dash_offset              (GskStroke              *self,
+                                                                 float                   offset);
+GDK_AVAILABLE_IN_4_14
+float                   gsk_stroke_get_dash_offset              (const GskStroke        *self);
+
+GDK_AVAILABLE_IN_4_14
+void                    gsk_stroke_to_cairo                     (const GskStroke        *self,
+                                                                 cairo_t                *cr);
+
+
+G_END_DECLS

gsk/gskstrokeprivate.h

@@ -0,0 +1,56 @@
+/*
+ * 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>
+ */
+
+
+#pragma once
+
+#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

gsk/gsktypes.h

@@ -25,6 +25,11 @@
 #include <gdk/gdk.h>
 #include <gsk/gskenums.h>
 
+typedef struct _GskPath                 GskPath;
+typedef struct _GskPathBuilder          GskPathBuilder;
+typedef struct _GskPathMeasure          GskPathMeasure;
+typedef struct _GskPathPoint            GskPathPoint;
 typedef struct _GskRenderer             GskRenderer;
+typedef struct _GskStroke               GskStroke;
 typedef struct _GskTransform            GskTransform;
 

gsk/meson.build

@@ -23,23 +23,32 @@ gsk_private_gl_shaders = [
 ]
 
 gsk_public_sources = files([
-  'gskdiff.c',
   'gskcairorenderer.c',
+  'gskdiff.c',
   'gskglshader.c',
+  'gskpath.c',
+  'gskpathdash.c',
+  'gskpathbuilder.c',
+  'gskpathmeasure.c',
+  'gskpathpoint.c',
   'gskrenderer.c',
   'gskrendernode.c',
   'gskrendernodeimpl.c',
   'gskrendernodeparser.c',
   'gskroundedrect.c',
+  'gskstroke.c',
   'gsktransform.c',
   'gl/gskglrenderer.c',
 ])
 
 gsk_private_sources = files([
   'gskcairoblur.c',
+  'gskcontour.c',
+  'gskcurve.c',
   'gskdebug.c',
   'gskprivate.c',
   'gskprofiler.c',
+  'gskspline.c',
   'gl/gskglattachmentstate.c',
   'gl/gskglbuffer.c',
   'gl/gskglcommandqueue.c',
@@ -66,9 +75,14 @@ gsk_public_headers = files([
   'gskcairorenderer.h',
   'gskenums.h',
   'gskglshader.h',
+  'gskpath.h',
+  'gskpathbuilder.h',
+  'gskpathmeasure.h',
+  'gskpathpoint.h',
   'gskrenderer.h',
   'gskrendernode.h',
   'gskroundedrect.h',
+  'gskstroke.h',
   'gsktransform.h',
   'gsktypes.h',
 ])

gsk/vulkan/gskvulkanrenderpass.c

@@ -1260,6 +1260,8 @@ static const GskVulkanRenderPassNodeFunc nodes_vtable[] = {
   [GSK_GL_SHADER_NODE] = NULL,
   [GSK_TEXTURE_SCALE_NODE] = gsk_vulkan_render_pass_add_texture_scale_node,
   [GSK_MASK_NODE] = gsk_vulkan_render_pass_add_mask_node,
+  [GSK_FILL_NODE] = NULL,
+  [GSK_STROKE_NODE] = NULL,
 };
 
 static void

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

@@ -30,6 +30,7 @@
 
 #include "gsk/gskrendernodeprivate.h"
 #include "gsk/gskroundedrectprivate.h"
+#include "gsk/gskstrokeprivate.h"
 
 #include "gtk/gskpangoprivate.h"
 
@@ -105,6 +106,14 @@ 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;
@@ -1096,6 +1105,141 @@ 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].
+ *
+ * Since: 4.14
+ */
+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
+ * an image.
+ *
+ * The image is recorded until the next call to [method@Gtk.Snapshot.pop].
+ *
+ * Since: 4.14
+ */
+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,

gtk/gtksnapshot.h

@@ -87,6 +87,14 @@ void            gtk_snapshot_push_clip                  (GtkSnapshot
 GDK_AVAILABLE_IN_ALL
 void            gtk_snapshot_push_rounded_clip          (GtkSnapshot            *snapshot,
                                                          const GskRoundedRect   *bounds);
+GDK_AVAILABLE_IN_4_14
+void            gtk_snapshot_push_fill                  (GtkSnapshot            *snapshot,
+                                                         GskPath                *path,
+                                                         GskFillRule             fill_rule);
+GDK_AVAILABLE_IN_4_14
+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,

gtk/inspector/recorder.c

@@ -298,6 +298,12 @@ 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);
 
@@ -425,6 +431,10 @@ 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:
@@ -466,6 +476,8 @@ 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_MASK_NODE:
@@ -894,6 +906,20 @@ add_float_row (GListStore  *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 (GListStore    *store,
                                  GskRenderNode *node)
@@ -1133,9 +1159,7 @@ populate_render_node_properties (GListStore    *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;
 
@@ -1377,6 +1401,39 @@ populate_render_node_properties (GListStore    *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);

testsuite/gsk/curve-special-cases.c

@@ -0,0 +1,223 @@
+/*
+ * 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 <gtk/gtk.h>
+
+#include "gsk/gskcurveprivate.h"
+
+static gboolean
+measure_segment (const graphene_point_t *from,
+                 const graphene_point_t *to,
+                 float                   from_t,
+                 float                   to_t,
+                 GskCurveLineReason      reason,
+                 gpointer                data)
+{
+  float *length = data;
+
+  *length += graphene_point_distance (from, to, NULL, NULL);
+
+  return TRUE;
+}
+
+static float
+measure_length (const GskCurve *curve)
+{
+  float result = 0;
+
+  gsk_curve_decompose (curve, 0.5, measure_segment, &result);
+
+  return result;
+}
+
+/* This is a pretty nasty conic that makes it obvious that split()
+ * does not respect the progress values, so split() twice  with
+ * scaled factor won't work.
+ */
+static void
+test_conic_segment (void)
+{
+  GskCurve c, s, e, m;
+  graphene_point_t pts[4] = {
+    GRAPHENE_POINT_INIT (-1856.131591796875, 46.217609405517578125),
+    GRAPHENE_POINT_INIT (-1555.9866943359375, 966.0810546875),
+    GRAPHENE_POINT_INIT (98.94945526123046875, 0),
+    GRAPHENE_POINT_INIT (-1471.33154296875, 526.701171875)
+  };
+  float start = 0.02222645096480846405029296875;
+  float end = 0.982032716274261474609375;
+
+  gsk_curve_init (&c, gsk_pathop_encode (GSK_PATH_CONIC, pts));
+
+  gsk_curve_split (&c, start, &s, NULL);
+  gsk_curve_segment (&c, start, end, &m);
+  gsk_curve_split (&c, end, NULL, &e);
+
+  g_assert_cmpfloat_with_epsilon (measure_length (&c), measure_length (&s) + measure_length (&m) + measure_length (&e), 0.03125);
+}
+
+static void
+test_curve_tangents (void)
+{
+  GskCurve c;
+  graphene_point_t p[4];
+  graphene_vec2_t t;
+
+  graphene_point_init (&p[0], 0, 0);
+  graphene_point_init (&p[1], 100, 0);
+  gsk_curve_init (&c, gsk_pathop_encode (GSK_PATH_LINE, p));
+
+  gsk_curve_get_start_tangent (&c, &t);
+  g_assert_true (graphene_vec2_near (&t, graphene_vec2_x_axis (), 0.0001));
+  gsk_curve_get_end_tangent (&c, &t);
+  g_assert_true (graphene_vec2_near (&t, graphene_vec2_x_axis (), 0.0001));
+
+  graphene_point_init (&p[0], 0, 0);
+  graphene_point_init (&p[1], 0, 100);
+  gsk_curve_init (&c, gsk_pathop_encode (GSK_PATH_LINE, p));
+
+  gsk_curve_get_start_tangent (&c, &t);
+  g_assert_true (graphene_vec2_near (&t, graphene_vec2_y_axis (), 0.0001));
+  gsk_curve_get_end_tangent (&c, &t);
+  g_assert_true (graphene_vec2_near (&t, graphene_vec2_y_axis (), 0.0001));
+
+  graphene_point_init (&p[0], 0, 0);
+  graphene_point_init (&p[1], 100, 0);
+  p[2] = GRAPHENE_POINT_INIT (g_test_rand_double_range (0, 20), 0);
+  graphene_point_init (&p[3], 100, 100);
+  gsk_curve_init (&c, gsk_pathop_encode (GSK_PATH_CONIC, p));
+
+  gsk_curve_get_start_tangent (&c, &t);
+  g_assert_true (graphene_vec2_near (&t, graphene_vec2_x_axis (), 0.0001));
+  gsk_curve_get_end_tangent (&c, &t);
+  g_assert_true (graphene_vec2_near (&t, graphene_vec2_y_axis (), 0.0001));
+
+  graphene_point_init (&p[0], 0, 0);
+  graphene_point_init (&p[1], 50, 0);
+  graphene_point_init (&p[2], 100, 50);
+  graphene_point_init (&p[3], 100, 100);
+  gsk_curve_init (&c, gsk_pathop_encode (GSK_PATH_CUBIC, p));
+
+  gsk_curve_get_start_tangent (&c, &t);
+  g_assert_true (graphene_vec2_near (&t, graphene_vec2_x_axis (), 0.0001));
+  gsk_curve_get_end_tangent (&c, &t);
+  g_assert_true (graphene_vec2_near (&t, graphene_vec2_y_axis (), 0.0001));
+}
+
+static void
+test_curve_degenerate_tangents (void)
+{
+  GskCurve c;
+  graphene_point_t p[4];
+  graphene_vec2_t t;
+
+  graphene_point_init (&p[0], 0, 0);
+  graphene_point_init (&p[1], 0, 0);
+  graphene_point_init (&p[2], 100, 0);
+  graphene_point_init (&p[3], 100, 0);
+  gsk_curve_init (&c, gsk_pathop_encode (GSK_PATH_CUBIC, p));
+
+  gsk_curve_get_start_tangent (&c, &t);
+  g_assert_true (graphene_vec2_near (&t, graphene_vec2_x_axis (), 0.0001));
+  gsk_curve_get_end_tangent (&c, &t);
+  g_assert_true (graphene_vec2_near (&t, graphene_vec2_x_axis (), 0.0001));
+
+  graphene_point_init (&p[0], 0, 0);
+  graphene_point_init (&p[1], 50, 0);
+  graphene_point_init (&p[2], 50, 0);
+  graphene_point_init (&p[3], 100, 0);
+  gsk_curve_init (&c, gsk_pathop_encode (GSK_PATH_CUBIC, p));
+
+  gsk_curve_get_start_tangent (&c, &t);
+  g_assert_true (graphene_vec2_near (&t, graphene_vec2_x_axis (), 0.0001));
+  gsk_curve_get_end_tangent (&c, &t);
+  g_assert_true (graphene_vec2_near (&t, graphene_vec2_x_axis (), 0.0001));
+}
+
+static gboolean
+pathop_cb (GskPathOperation        op,
+           const graphene_point_t *pts,
+           gsize                   n_pts,
+           float                   weight,
+           gpointer                user_data)
+{
+  GskCurve *curve = user_data;
+
+  g_assert (op != GSK_PATH_CLOSE);
+
+  if (op == GSK_PATH_MOVE)
+    return TRUE;
+
+  gsk_curve_init_foreach (curve, op, pts, n_pts, weight);
+  return FALSE;
+}
+
+static void
+parse_curve (GskCurve   *c,
+             const char *str)
+{
+  GskPath *path = gsk_path_parse (str);
+
+  gsk_path_foreach (path, -1, pathop_cb, c);
+
+  gsk_path_unref (path);
+}
+
+static void
+test_curve_crossing (void)
+{
+  struct {
+    const char *c;
+    const graphene_point_t p;
+    int crossing;
+  } tests[] = {
+    { "M 0 0 L 200 200", { 200, 100 }, 0 },
+    { "M 0 0 L 200 200", { 0, 100 }, 1 },
+    { "M 0 200 L 200 0", { 0, 100 }, -1 },
+    { "M 0 0 C 100 100 200 200 300 300", { 200, 100 }, 0 },
+    { "M 0 0 C 100 100 200 200 300 300", { 0, 100 }, 1 },
+    { "M 0 300 C 100 200 200 100 300 0", { 0, 100 }, -1 },
+    { "M 0 0 C 100 600 200 -300 300 300", { 0, 150 }, 1 },
+    { "M 0 0 C 100 600 200 -300 300 300", { 100, 150 }, 0 },
+    { "M 0 0 C 100 600 200 -300 300 300", { 200, 150 }, 1 },
+  };
+
+  for (unsigned int i = 0; i < G_N_ELEMENTS (tests); i++)
+    {
+      GskCurve c;
+
+      parse_curve (&c, tests[i].c);
+
+      g_assert_true (gsk_curve_get_crossing (&c, &tests[i].p) == tests[i].crossing);
+    }
+}
+
+int
+main (int   argc,
+      char *argv[])
+{
+  gtk_test_init (&argc, &argv, NULL);
+
+  g_test_add_func ("/curve/special/conic-segment", test_conic_segment);
+  g_test_add_func ("/curve/special/tangents", test_curve_tangents);
+  g_test_add_func ("/curve/special/degenerate-tangents", test_curve_degenerate_tangents);
+  g_test_add_func ("/curve/special/crossing", test_curve_crossing);
+
+  return g_test_run ();
+}

testsuite/gsk/curve.c

@@ -0,0 +1,422 @@
+#include <gtk/gtk.h>
+#include "gsk/gskcurveprivate.h"
+
+static void
+init_random_point (graphene_point_t *p)
+{
+  p->x = g_test_rand_double_range (0, 1000);
+  p->y = g_test_rand_double_range (0, 1000);
+}
+
+static float
+random_weight (void)
+{
+  if (g_test_rand_bit ())
+    return g_test_rand_double_range (1, 20);
+  else
+    return 1.0 / g_test_rand_double_range (1, 20);
+}
+
+static void
+init_random_curve_with_op (GskCurve         *curve,
+                           GskPathOperation  min_op,
+                           GskPathOperation  max_op)
+{
+  switch (g_test_rand_int_range (min_op, max_op + 1))
+    {
+    case GSK_PATH_LINE:
+      {
+        graphene_point_t p[2];
+
+        init_random_point (&p[0]);
+        init_random_point (&p[1]);
+        gsk_curve_init (curve, gsk_pathop_encode (GSK_PATH_LINE, p));
+      }
+      break;
+
+    case GSK_PATH_QUAD:
+      {
+        graphene_point_t p[3];
+
+        init_random_point (&p[0]);
+        init_random_point (&p[1]);
+        init_random_point (&p[2]);
+        gsk_curve_init (curve, gsk_pathop_encode (GSK_PATH_QUAD, p));
+      }
+    break;
+
+    case GSK_PATH_CUBIC:
+      {
+        graphene_point_t p[4];
+
+        init_random_point (&p[0]);
+        init_random_point (&p[1]);
+        init_random_point (&p[2]);
+        init_random_point (&p[3]);
+        gsk_curve_init (curve, gsk_pathop_encode (GSK_PATH_CUBIC, p));
+      }
+    break;
+
+    case GSK_PATH_CONIC:
+      {
+        graphene_point_t p[4];
+
+        init_random_point (&p[0]);
+        init_random_point (&p[1]);
+        p[2] = GRAPHENE_POINT_INIT (random_weight(), 0);
+        init_random_point (&p[3]);
+        gsk_curve_init (curve, gsk_pathop_encode (GSK_PATH_CONIC, p));
+      }
+      break;
+
+    default:
+      g_assert_not_reached ();
+    }
+}
+
+static void
+init_random_curve (GskCurve *curve)
+{
+  init_random_curve_with_op (curve, GSK_PATH_LINE, GSK_PATH_CONIC);
+}
+
+static void
+test_curve_tangents (void)
+{
+  for (int i = 0; i < 100; i++)
+    {
+      GskCurve c;
+      graphene_vec2_t vec, exact;
+
+      init_random_curve (&c);
+
+      gsk_curve_get_tangent (&c, 0, &vec);
+      g_assert_cmpfloat_with_epsilon (graphene_vec2_length (&vec), 1.0f, 0.00001);
+      gsk_curve_get_start_tangent (&c, &exact);
+      g_assert_cmpfloat_with_epsilon (graphene_vec2_length (&exact), 1.0f, 0.00001);
+      g_assert_true (graphene_vec2_near (&vec, &exact, 0.05));
+
+      gsk_curve_get_tangent (&c, 1, &vec);
+      g_assert_cmpfloat_with_epsilon (graphene_vec2_length (&vec), 1.0f, 0.00001);
+      gsk_curve_get_end_tangent (&c, &exact);
+      g_assert_cmpfloat_with_epsilon (graphene_vec2_length (&exact), 1.0f, 0.00001);
+      g_assert_true (graphene_vec2_near (&vec, &exact, 0.05));
+    }
+}
+
+static void
+test_curve_points (void)
+{
+  for (int i = 0; i < 100; i++)
+    {
+      GskCurve c;
+      graphene_point_t p;
+
+      init_random_curve (&c);
+
+      /* We can assert equality here because evaluating the polynomials with 0
+       * has no effect on accuracy.
+       */
+      gsk_curve_get_point (&c, 0, &p);
+      g_assert_true (graphene_point_equal (gsk_curve_get_start_point (&c), &p));
+      /* But here we evaluate the polynomials with 1 which gives the highest possible
+       * accuracy error. So we'll just be generous here.
+       */
+      gsk_curve_get_point (&c, 1, &p);
+      g_assert_true (graphene_point_near (gsk_curve_get_end_point (&c), &p, 0.05));
+    }
+}
+
+/* at this point the subdivision stops and the decomposer
+ * violates tolerance rules
+ */
+#define MIN_PROGRESS (1/1024.f)
+
+typedef struct
+{
+  graphene_point_t p;
+  float t;
+} PointOnLine;
+
+static gboolean
+add_line_to_array (const graphene_point_t *from,
+                   const graphene_point_t *to,
+                   float                   from_progress,
+                   float                   to_progress,
+                   GskCurveLineReason      reason,
+                   gpointer                user_data)
+{
+  GArray *array = user_data;
+  PointOnLine *last = &g_array_index (array, PointOnLine, array->len - 1);
+
+  g_assert_true (array->len > 0);
+  g_assert_cmpfloat (from_progress, >=, 0.0f);
+  g_assert_cmpfloat (from_progress, <, to_progress);
+  g_assert_cmpfloat (to_progress, <=, 1.0f);
+
+  g_assert_true (graphene_point_equal (&last->p, from));
+  g_assert_cmpfloat (last->t, ==, from_progress);
+
+  g_array_append_vals (array, (PointOnLine[1]) { { *to, to_progress } }, 1);
+
+  return TRUE;
+}
+
+static void
+test_curve_decompose (void)
+{
+  static const float tolerance = 0.5;
+
+  for (int i = 0; i < 100; i++)
+    {
+      GArray *array;
+      GskCurve c;
+
+      init_random_curve (&c);
+
+      array = g_array_new (FALSE, FALSE, sizeof (PointOnLine));
+      g_array_append_vals (array, (PointOnLine[1]) { { *gsk_curve_get_start_point (&c), 0.f } }, 1);
+
+      g_assert_true (gsk_curve_decompose (&c, tolerance, add_line_to_array, array));
+
+      g_assert_cmpint (array->len, >=, 2); /* We at least got a line to the end */
+      g_assert_cmpfloat (g_array_index (array, PointOnLine, array->len - 1).t, ==, 1.0);
+
+      for (int j = 0; j < array->len; j++)
+        {
+          PointOnLine *pol = &g_array_index (array, PointOnLine, j);
+          graphene_point_t p;
+
+          /* Check that the points we got are actually on the line */
+          gsk_curve_get_point (&c, pol->t, &p);
+          g_assert_true (graphene_point_near (&pol->p, &p, 0.05));
+
+          /* Check that the mid point is not further than the tolerance */
+          if (j > 0)
+            {
+              PointOnLine *last = &g_array_index (array, PointOnLine, j - 1);
+              graphene_point_t mid;
+
+              if (pol->t - last->t > MIN_PROGRESS)
+                {
+                  graphene_point_interpolate (&last->p, &pol->p, 0.5, &mid);
+                  gsk_curve_get_point (&c, (pol->t + last->t) / 2, &p);
+                  /* The decomposer does this cheaper Manhattan distance test,
+                   * so graphene_point_near() does not work */
+                  g_assert_cmpfloat (fabs (mid.x - p.x), <=, tolerance);
+                  g_assert_cmpfloat (fabs (mid.y - p.y), <=, tolerance);
+                }
+            }
+        }
+
+      g_array_unref (array);
+    }
+}
+
+static gboolean
+add_curve_to_array (GskPathOperation        op,
+                    const graphene_point_t *pts,
+                    gsize                   n_pts,
+                    float                   weight,
+                    gpointer                user_data)
+{
+  GArray *array = user_data;
+  GskCurve c;
+
+  gsk_curve_init_foreach (&c, op, pts, n_pts, weight);
+  g_array_append_val (array, c);
+
+  return TRUE;
+}
+
+static void
+test_curve_decompose_conic (void)
+{
+  g_test_skip ("No good error bounds for decomposing conics");
+  return;
+
+  for (int i = 0; i < 100; i++)
+    {
+      GArray *array;
+      GskCurve c;
+      GskPathBuilder *builder;
+      GskPath *path;
+      GskPathMeasure *measure;
+      const graphene_point_t *s;
+
+      init_random_curve_with_op (&c, GSK_PATH_CONIC, GSK_PATH_CONIC);
+
+      builder = gsk_path_builder_new ();
+
+      s = gsk_curve_get_start_point (&c);
+      gsk_path_builder_move_to (builder, s->x, s->y);
+      gsk_curve_builder_to (&c, builder);
+      path = gsk_path_builder_free_to_path (builder);
+      measure = gsk_path_measure_new_with_tolerance (path, 0.1);
+
+      array = g_array_new (FALSE, FALSE, sizeof (GskCurve));
+
+      g_assert_true (gsk_curve_decompose_curve (&c, GSK_PATH_FOREACH_ALLOW_CUBIC, 0.1, add_curve_to_array, array));
+
+      g_assert_cmpint (array->len, >=, 1);
+
+      for (int j = 0; j < array->len; j++)
+        {
+          GskCurve *c2 = &g_array_index (array, GskCurve, j);
+
+          g_assert_true (c2->op == GSK_PATH_CUBIC);
+
+          /* Check that the curves we got are approximating the conic */
+          for (int k = 0; k < 11; k++)
+            {
+              GskPathPoint point;
+              graphene_point_t p, q;
+
+              gsk_curve_get_point (c2, k/10.0, &p);
+              if (gsk_path_get_closest_point (path, &p, INFINITY, &point))
+                {
+                  gsk_path_point_get_position (&point, &q);
+                  g_assert_true (graphene_point_near (&p, &q, 0.5));
+                }
+            }
+        }
+
+      g_array_unref (array);
+
+      gsk_path_measure_unref (measure);
+      gsk_path_unref (path);
+    }
+}
+
+static void
+test_curve_decompose_into (GskPathForeachFlags flags)
+{
+  for (int i = 0; i < 100; i++)
+    {
+      GskCurve c;
+      GskPathBuilder *builder;
+      const graphene_point_t *s;
+      GskPath *path;
+      GArray *array;
+
+      init_random_curve (&c);
+
+      builder = gsk_path_builder_new ();
+
+      s = gsk_curve_get_start_point (&c);
+      gsk_path_builder_move_to (builder, s->x, s->y);
+      gsk_curve_builder_to (&c, builder);
+      path = gsk_path_builder_free_to_path (builder);
+
+      array = g_array_new (FALSE, FALSE, sizeof (GskCurve));
+
+      g_assert_true (gsk_curve_decompose_curve (&c, flags, 0.1, add_curve_to_array, array));
+
+      g_assert_cmpint (array->len, >=, 1);
+
+      for (int j = 0; j < array->len; j++)
+        {
+          GskCurve *c2 = &g_array_index (array, GskCurve, j);
+
+          switch (c2->op)
+            {
+            case GSK_PATH_MOVE:
+            case GSK_PATH_CLOSE:
+            case GSK_PATH_LINE:
+              break;
+            case GSK_PATH_QUAD:
+              g_assert_true (flags & GSK_PATH_FOREACH_ALLOW_QUAD);
+              break;
+            case GSK_PATH_CUBIC:
+              g_assert_true (flags & GSK_PATH_FOREACH_ALLOW_CUBIC);
+              break;
+            case GSK_PATH_CONIC:
+              g_assert_true (flags & GSK_PATH_FOREACH_ALLOW_CONIC);
+              break;
+            default:
+              g_assert_not_reached ();
+            }
+        }
+
+      g_array_unref (array);
+      gsk_path_unref (path);
+    }
+}
+
+static void
+test_curve_decompose_into_line (void)
+{
+  test_curve_decompose_into (0);
+}
+
+static void
+test_curve_decompose_into_quad (void)
+{
+  test_curve_decompose_into (GSK_PATH_FOREACH_ALLOW_QUAD);
+}
+
+static void
+test_curve_decompose_into_cubic (void)
+{
+  test_curve_decompose_into (GSK_PATH_FOREACH_ALLOW_CUBIC);
+}
+
+/* Some sanity checks for splitting curves. */
+static void
+test_curve_split (void)
+{
+  for (int i = 0; i < 100; i++)
+    {
+      GskCurve c;
+      GskCurve c1, c2;
+      graphene_point_t p;
+      graphene_vec2_t t, t1, t2;
+
+      init_random_curve (&c);
+
+      gsk_curve_split (&c, 0.5, &c1, &c2);
+
+      g_assert_true (c1.op == c.op);
+      g_assert_true (c2.op == c.op);
+
+      g_assert_true (graphene_point_near (gsk_curve_get_start_point (&c),
+                                          gsk_curve_get_start_point (&c1), 0.005));
+      g_assert_true (graphene_point_near (gsk_curve_get_end_point (&c1),
+                                          gsk_curve_get_start_point (&c2), 0.005));
+      g_assert_true (graphene_point_near (gsk_curve_get_end_point (&c),
+                                          gsk_curve_get_end_point (&c2), 0.005));
+      gsk_curve_get_point (&c, 0.5, &p);
+      gsk_curve_get_tangent (&c, 0.5, &t);
+      g_assert_true (graphene_point_near (gsk_curve_get_end_point (&c1), &p, 0.005));
+      g_assert_true (graphene_point_near (gsk_curve_get_start_point (&c2), &p, 0.005));
+
+      gsk_curve_get_start_tangent (&c, &t1);
+      gsk_curve_get_start_tangent (&c1, &t2);
+      g_assert_true (graphene_vec2_near (&t1, &t2, 0.005));
+      gsk_curve_get_end_tangent (&c1, &t1);
+      gsk_curve_get_start_tangent (&c2, &t2);
+      g_assert_true (graphene_vec2_near (&t1, &t2, 0.005));
+      g_assert_true (graphene_vec2_near (&t, &t1, 0.005));
+      g_assert_true (graphene_vec2_near (&t, &t2, 0.005));
+      gsk_curve_get_end_tangent (&c, &t1);
+      gsk_curve_get_end_tangent (&c2, &t2);
+      g_assert_true (graphene_vec2_near (&t1, &t2, 0.005));
+    }
+}
+
+int
+main (int argc, char *argv[])
+{
+  (g_test_init) (&argc, &argv, NULL);
+
+  g_test_add_func ("/curve/points", test_curve_points);
+  g_test_add_func ("/curve/tangents", test_curve_tangents);
+  g_test_add_func ("/curve/decompose", test_curve_decompose);
+  g_test_add_func ("/curve/decompose/conic", test_curve_decompose_conic);
+  g_test_add_func ("/curve/decompose/into/line", test_curve_decompose_into_line);
+  g_test_add_func ("/curve/decompose/into/quad", test_curve_decompose_into_quad);
+  g_test_add_func ("/curve/decompose/into/cubic", test_curve_decompose_into_cubic);
+  g_test_add_func ("/curve/split", test_curve_split);
+
+  return g_test_run ();
+}

testsuite/gsk/dash.c

@@ -0,0 +1,183 @@
+/*
+ * 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 <gtk/gtk.h>
+
+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_QUAD:
+      gsk_path_builder_quad_to (builder, pts[1].x, pts[1].y, pts[2].x, pts[2].y);
+      break;
+
+    case GSK_PATH_CUBIC:
+      gsk_path_builder_cubic_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 void
+test_simple (void)
+{
+  const struct {
+    const char *test;
+    float dash[4];
+    gsize n_dash;
+    float dash_offset;
+    const char *result;
+  } tests[] = {
+    /* a line with a dash of a quarter its size, very simple test */
+    {
+      "M 0 0 L 20 0",
+      { 5, }, 1, 0.f,
+      "M 0 0 L 5 0 M 10 0 L 15 0",
+    },
+    /* a square with a dash of half its size, another simple test */
+    {
+      "M 0 0 h 10 v 10 h -10 z",
+      { 5, }, 1, 0.f,
+      "M 10 0 L 10 5 M 10 10 L 5 10 M 0 10 L 0 5 M 0 0 L 5 0"
+    },
+    /* a square smaller than the dash, make sure it closes */
+    {
+      "M 0 0 h 10 v 10 h -10 z",
+      { 50, }, 1, 0.f,
+      "M 0 0 L 10 0 L 10 10 L 0 10 Z"
+    },
+    /* a square exactly the dash's size, make sure it still closes */
+    {
+      "M 0 0 h 10 v 10 h -10 z",
+      { 40, }, 1, 0.f,
+      "M 0 0 L 10 0 L 10 10 L 0 10 Z"
+    },
+    /* a dash with offset */
+    {
+      "M 0 0 h 10 v 10 h -10 z",
+      { 5, }, 1, 2.5f,
+      "M 7.5 0 L 10 0 L 10 2.5 M 10 7.5 L 10 10 L 7.5 10 M 2.5 10 L 0 10 L 0 7.5 M 0 2.5 L 0 0 L 2.5 0"
+    },
+    /* a dash with offset, but this time the rect isn't closed */
+    {
+      "M 0 0 L 10 0 L 10 10 L 0 10 L 0 0",
+      { 5, }, 1, 2.5f,
+      "M 0 0 L 2.5 0 M 7.5 0 L 10 0 L 10 2.5 M 10 7.5 L 10 10 L 7.5 10 M 2.5 10 L 0 10 L 0 7.5 M 0 2.5 L 0 0"
+    },
+    /* a dash with offset into an empty dash */
+    {
+      "M 0 0 h 10 v 10 h -10 z",
+      { 5, }, 1, 7.5f,
+      "M 2.5 0 L 7.5 0 M 10 2.5 L 10 7.5 M 7.5 10 L 2.5 10 M 0 7.5 L 0 2.5"
+    },
+    /* a dash with offset where the whole rectangle fits into one element - make sure it closes */
+    {
+      "M 0 0 h 10 v 10 h -10 z",
+      { 1, 1, 100 }, 3, 3.f,
+      "M 0 0 L 10 0 L 10 10 L 0 10 Z"
+    },
+    /* a dash with 0-length elements, aka dotting */
+    {
+      "M 0 0 h 10 v 10 h -10 z",
+      { 0, 5 }, 2, 0.f,
+      "M 5 0 M 10 0 M 10 5 M 10 10 M 5 10 M 0 10 M 0 5 M 0 0"
+    },
+    /* a dash of a circle */
+    {
+      "M 10 5 O 10 10, 5 10, 0.70710676908493042 O 0 10, 0 5, 0.70710676908493042 O 0 0, 5 0, 0.70710676908493042 O 10 0, 10 5, 0.70710676908493042 Z",
+      { 32, }, 1, 0.f,
+      "M 10 5 O 10 10, 5 10, 0.70710676908493042 O 0 10, 0 5, 0.70710676908493042 O 0 0, 5 0, 0.70710676908493042 O 10 0, 10 5, 0.70710676908493042 Z",
+    },
+    /* a dash with offset and 2 contours */
+    {
+      "M 10 10 h 10 v 10 h -10 z M 20 20 h 10 v 10 h -10 z",
+      { 5, }, 1, 2.5f,
+      "M 17.5 10 L 20 10 L 20 12.5 M 20 17.5 L 20 20 L 17.5 20 M 12.5 20 L 10 20 L 10 17.5 M 10 12.5 L 10 10 L 12.5 10 "
+      "M 27.5 20 L 30 20 L 30 22.5 M 30 27.5 L 30 30 L 27.5 30 M 22.5 30 L 20 30 L 20 27.5 M 20 22.5 L 20 20 L 22.5 20"
+    },
+  };
+  GskPath *path, *result;
+  GskPathBuilder *builder;
+  GskStroke *stroke;
+  char *s;
+
+  for (gsize i = 0; i < G_N_ELEMENTS(tests); i++)
+    {
+      stroke = gsk_stroke_new (1);
+      gsk_stroke_set_dash (stroke, tests[i].dash, tests[i].n_dash);
+      gsk_stroke_set_dash_offset (stroke, tests[i].dash_offset);
+
+      path = gsk_path_parse (tests[i].test);
+      g_assert_nonnull (path);
+      s = gsk_path_to_string (path);
+      g_assert_cmpstr (s, ==, tests[i].test);
+      g_free (s);
+
+      builder = gsk_path_builder_new ();
+      gsk_path_dash (path, stroke, 0.5, build_path, builder);
+      result = gsk_path_builder_free_to_path (builder);
+
+      s = gsk_path_to_string (result);
+      g_assert_cmpstr (s, ==, tests[i].result);
+      g_free (s);
+
+      gsk_path_unref (result);
+      gsk_stroke_free (stroke);
+      gsk_path_unref (path);
+    }
+}
+
+int
+main (int   argc,
+      char *argv[])
+{
+  gtk_test_init (&argc, &argv, NULL);
+
+  g_test_add_func ("/dash/simple", test_simple);
+
+  return g_test_run ();
+}

testsuite/gsk/measure-special-cases.c

@@ -0,0 +1,265 @@
+/*
+ * 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 <gtk/gtk.h>
+
+
+static void
+test_bad_split (void)
+{
+  GskPath *path, *path1;
+  GskPathMeasure *measure, *measure1;
+  GskPathBuilder *builder;
+  float split, length, epsilon;
+
+  /* An example that was isolated from the /path/segment test path.c
+   * It shows how uneven parametrization of cubics can lead to bad
+   * lengths reported by the measure.
+   */
+
+  path = gsk_path_parse ("M 0 0 C 2 0 4 0 4 0");
+
+  measure = gsk_path_measure_new (path);
+  split = 2.962588;
+  length = gsk_path_measure_get_length (measure);
+  epsilon = MAX (length / 256, 1.f / 1024);
+
+  builder = gsk_path_builder_new ();
+  gsk_path_builder_add_segment (builder, measure, 0, split);
+  path1 = gsk_path_builder_free_to_path (builder);
+  measure1 = gsk_path_measure_new (path1);
+
+  g_assert_cmpfloat_with_epsilon (split, gsk_path_measure_get_length (measure1), epsilon);
+
+  gsk_path_measure_unref (measure1);
+  gsk_path_unref (path1);
+  gsk_path_measure_unref (measure);
+  gsk_path_unref (path);
+}
+
+static void
+test_bad_in_fill (void)
+{
+  GskPath *path;
+  gboolean inside;
+
+  /* A fat Cantarell W */
+  path = gsk_path_parse ("M -2 694 M 206.1748046875 704 L 390.9371337890625 704 L 551.1888427734375 99.5035400390625 L 473.0489501953125 99.5035400390625 L 649.1048583984375 704 L 828.965087890625 704 L 1028.3077392578125 10 L 857.8111572265625 10 L 710.0489501953125 621.251708984375 L 775.9720458984375 598.426513671875 L 614.5245361328125 14.0489501953125 L 430.2237548828125 14.0489501953125 L 278.6783447265625 602.230712890625 L 330.0909423828125 602.230712890625 L 195.88818359375 10 L 5.7342529296875 10 L 206.1748046875 704 Z");
+
+  /* The midpoint of the right foot of a fat Cantarell X */
+  inside = gsk_path_in_fill (path, &GRAPHENE_POINT_INIT (552.360107, 704.000000), GSK_FILL_RULE_WINDING);
+
+  g_assert_false (inside);
+
+  gsk_path_unref (path);
+}
+
+/* Test that path_in_fill implicitly closes contours. I think this is wrong,
+ * but it is what "everybody" does.
+ */
+static void
+test_unclosed_in_fill (void)
+{
+  GskPath *path;
+
+  path = gsk_path_parse ("M 0 0 L 0 100 L 100 100 L 100 0 Z");
+  g_assert_true (gsk_path_in_fill (path, &GRAPHENE_POINT_INIT (50, 50), GSK_FILL_RULE_WINDING));
+  gsk_path_unref (path);
+
+  path = gsk_path_parse ("M 0 0 L 0 100 L 100 100 L 100 0");
+  g_assert_true (gsk_path_in_fill (path, &GRAPHENE_POINT_INIT (50, 50), GSK_FILL_RULE_WINDING));
+  gsk_path_unref (path);
+}
+
+static void
+test_rect (void)
+{
+  GskPathBuilder *builder;
+  GskPath *path;
+  GskPathMeasure *measure;
+  GskPathPoint point;
+  graphene_point_t p;
+  graphene_vec2_t tangent, expected_tangent;
+  float length;
+  gboolean ret;
+
+  builder = gsk_path_builder_new ();
+  gsk_path_builder_add_rect (builder, &GRAPHENE_RECT_INIT (0, 0, 100, 50));
+  path = gsk_path_builder_free_to_path (builder);
+  measure = gsk_path_measure_new (path);
+  length = gsk_path_measure_get_length (measure);
+
+  g_assert_true (length == 300);
+
+#define TEST_POS_AT(distance, X, Y) \
+  ret = gsk_path_measure_get_point (measure, distance, &point); \
+  g_assert_true (ret); \
+  gsk_path_point_get_position (&point, &p); \
+  g_assert_true (graphene_point_near (&p, &GRAPHENE_POINT_INIT (X, Y), 0.01)); \
+  ret = gsk_path_get_closest_point (path, &GRAPHENE_POINT_INIT (X, Y), INFINITY, &point); \
+  g_assert_true (ret); \
+  if (distance < length) \
+    g_assert_true (fabs (gsk_path_measure_get_distance (measure, &point) - distance) < 0.01); \
+  else \
+    g_assert_true (fabs (gsk_path_measure_get_distance (measure, &point)) < 0.01); \
+  gsk_path_point_get_position (&point, &p); \
+  g_assert_true (graphene_point_near (&p, &GRAPHENE_POINT_INIT (X, Y), 0.01)); \
+
+#define TEST_TANGENT_AT(distance, x1, y1, x2, y2) \
+  ret = gsk_path_measure_get_point (measure, distance, &point); \
+  g_assert_true (ret); \
+  gsk_path_point_get_tangent (&point, GSK_PATH_START, &tangent); \
+  g_assert_true (graphene_vec2_near (&tangent, graphene_vec2_init (&expected_tangent, x1, y1), 0.01)); \
+  gsk_path_point_get_tangent (&point, GSK_PATH_END, &tangent); \
+  g_assert_true (graphene_vec2_near (&tangent, graphene_vec2_init (&expected_tangent, x2, y2), 0.01)); \
+
+#define TEST_POS_AT2(distance, X, Y, expected_distance) \
+  ret = gsk_path_measure_get_point (measure, distance, &point); \
+  g_assert_true (ret); \
+  gsk_path_point_get_position (&point, &p); \
+  g_assert_true (graphene_point_near (&p, &GRAPHENE_POINT_INIT (X, Y), 0.01)); \
+  ret = gsk_path_get_closest_point (path, &GRAPHENE_POINT_INIT (X, Y), INFINITY, &point); \
+  g_assert_true (ret); \
+  g_assert_true (fabs (gsk_path_measure_get_distance (measure, &point) - expected_distance) < 0.01); \
+  gsk_path_point_get_position (&point, &p); \
+  g_assert_true (graphene_point_near (&p, &GRAPHENE_POINT_INIT (X, Y), 0.01)); \
+
+  TEST_POS_AT (0, 0, 0)
+  TEST_POS_AT (25, 25, 0)
+  TEST_POS_AT (100, 100, 0)
+  TEST_POS_AT (110, 100, 10)
+  TEST_POS_AT (150, 100, 50)
+  TEST_POS_AT (175, 75, 50)
+  TEST_POS_AT (250, 0, 50)
+  TEST_POS_AT (260, 0, 40)
+  TEST_POS_AT (300, 0, 0)
+
+  TEST_TANGENT_AT (0, 0, -1, 1, 0)
+  TEST_TANGENT_AT (50, 1, 0, 1, 0)
+  TEST_TANGENT_AT (100, 1, 0, 0, 1)
+  TEST_TANGENT_AT (125, 0, 1, 0, 1)
+  TEST_TANGENT_AT (150, 0, 1, -1, 0)
+  TEST_TANGENT_AT (200, -1, 0, -1, 0)
+  TEST_TANGENT_AT (250, -1, 0, 0, -1)
+  TEST_TANGENT_AT (275, 0, -1, 0, -1)
+
+  gsk_path_measure_unref (measure);
+  gsk_path_unref (path);
+
+  builder = gsk_path_builder_new ();
+  gsk_path_builder_add_rect (builder, &GRAPHENE_RECT_INIT (100, 50, -100, -50));
+  path = gsk_path_builder_free_to_path (builder);
+  measure = gsk_path_measure_new (path);
+  length = gsk_path_measure_get_length (measure);
+
+  g_assert_true (length == 300);
+
+  TEST_POS_AT (0, 100, 50)
+  TEST_POS_AT (25, 75, 50)
+  TEST_POS_AT (100, 0, 50)
+  TEST_POS_AT (110, 0, 40)
+  TEST_POS_AT (150, 0, 0)
+  TEST_POS_AT (175, 25, 0)
+  TEST_POS_AT (250, 100, 0)
+  TEST_POS_AT (260, 100, 10)
+  TEST_POS_AT (300, 100, 50)
+
+  builder = gsk_path_builder_new ();
+  gsk_path_builder_add_rect (builder, &GRAPHENE_RECT_INIT (100, 0, -100, 50));
+  path = gsk_path_builder_free_to_path (builder);
+  measure = gsk_path_measure_new (path);
+  length = gsk_path_measure_get_length (measure);
+
+  g_assert_true (length == 300);
+
+  TEST_POS_AT (0, 100, 0)
+  TEST_POS_AT (25, 75, 0)
+  TEST_POS_AT (100, 0, 0)
+  TEST_POS_AT (110, 0, 10)
+  TEST_POS_AT (150, 0, 50)
+  TEST_POS_AT (175, 25, 50)
+  TEST_POS_AT (250, 100, 50)
+  TEST_POS_AT (260, 100, 40)
+  TEST_POS_AT (300, 100, 0)
+
+  builder = gsk_path_builder_new ();
+  gsk_path_builder_add_rect (builder, &GRAPHENE_RECT_INIT (0, 0, 100, 0));
+  path = gsk_path_builder_free_to_path (builder);
+  measure = gsk_path_measure_new (path);
+  length = gsk_path_measure_get_length (measure);
+
+  g_assert_true (length == 200);
+
+  TEST_POS_AT2 (0, 0, 0, 0)
+  TEST_POS_AT2 (25, 25, 0, 25)
+  TEST_POS_AT2 (100, 100, 0, 100)
+  TEST_POS_AT2 (110, 90, 0, 90)
+  TEST_POS_AT2 (200, 0, 0, 0)
+
+  builder = gsk_path_builder_new ();
+  gsk_path_builder_add_rect (builder, &GRAPHENE_RECT_INIT (100, 0, -100, 0));
+  path = gsk_path_builder_free_to_path (builder);
+  measure = gsk_path_measure_new (path);
+  length = gsk_path_measure_get_length (measure);
+
+  g_assert_true (length == 200);
+
+  /* These cases are ambiguous */
+  TEST_POS_AT2 (0, 100, 0, 0)
+  TEST_POS_AT2 (25, 75, 0, 25)
+  TEST_POS_AT2 (100, 0, 0, 100)
+  TEST_POS_AT2 (110, 10, 0, 90)
+  TEST_POS_AT2 (200, 100, 0, 0)
+
+  builder = gsk_path_builder_new ();
+  gsk_path_builder_add_rect (builder, &GRAPHENE_RECT_INIT (0, 100, 0, -100));
+  path = gsk_path_builder_free_to_path (builder);
+  measure = gsk_path_measure_new (path);
+  length = gsk_path_measure_get_length (measure);
+
+  g_assert_true (length == 200);
+
+  /* These cases are ambiguous */
+  TEST_POS_AT2 (0, 0, 100, 0)
+  TEST_POS_AT2 (25, 0, 75, 175)
+  TEST_POS_AT2 (100, 0, 0, 100)
+  TEST_POS_AT2 (110, 0, 10, 110)
+  TEST_POS_AT2 (200, 0, 100, 0)
+
+#undef TEST_POS_AT
+#undef TEST_POS_AT2
+#undef TEST_TANGENT_AT
+
+  gsk_path_measure_unref (measure);
+  gsk_path_unref (path);
+}
+
+int
+main (int   argc,
+      char *argv[])
+{
+  gtk_test_init (&argc, &argv, NULL);
+
+  g_test_add_func ("/measure/bad-split", test_bad_split);
+  g_test_add_func ("/measure/bad-in-fill", test_bad_in_fill);
+  g_test_add_func ("/measure/unclosed-in-fill", test_unclosed_in_fill);
+  g_test_add_func ("/measure/rect", test_rect);
+
+  return g_test_run ();
+}

testsuite/gsk/measure.c

@@ -0,0 +1,917 @@
+/*
+ * 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 <gtk/gtk.h>
+
+static float
+random_weight (void)
+{
+  if (g_test_rand_bit ())
+    return g_test_rand_double_range (1, 20);
+  else
+    return 1.0 / g_test_rand_double_range (1, 20);
+}
+
+static GskPath *
+create_random_degenerate_path (guint max_contours)
+{
+#define N_DEGENERATE_PATHS 15
+  GskPathBuilder *builder;
+  guint i;
+
+  builder = gsk_path_builder_new ();
+
+  switch (g_test_rand_int_range (0, N_DEGENERATE_PATHS))
+  {
+    case 0:
+      /* empty path */
+      break;
+
+    case 1:
+      /* a single point */
+      gsk_path_builder_move_to (builder, 
+                                g_test_rand_double_range (-1000, 1000),
+                                g_test_rand_double_range (-1000, 1000));
+      break;
+
+    case 2:
+      /* N points */
+      for (i = 0; i < MIN (10, max_contours); i++)
+        {
+          gsk_path_builder_move_to (builder, 
+                                    g_test_rand_double_range (-1000, 1000),
+                                    g_test_rand_double_range (-1000, 1000));
+        }
+      break;
+
+    case 3:
+      /* 1 closed point */
+      gsk_path_builder_move_to (builder, 
+                                g_test_rand_double_range (-1000, 1000),
+                                g_test_rand_double_range (-1000, 1000));
+      gsk_path_builder_close (builder);
+      break;
+
+    case 4:
+      /* the same point closed N times */
+      gsk_path_builder_move_to (builder, 
+                                g_test_rand_double_range (-1000, 1000),
+                                g_test_rand_double_range (-1000, 1000));
+      for (i = 0; i < MIN (10, max_contours); i++)
+        {
+          gsk_path_builder_close (builder);
+        }
+      break;
+
+    case 5:
+      /* a zero-width and zero-height rect */
+      gsk_path_builder_add_rect (builder,
+                                 &GRAPHENE_RECT_INIT (g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000),
+                                                      0, 0));
+      break;
+
+    case 6:
+      /* a zero-width rect */
+      gsk_path_builder_add_rect (builder,
+                                 &GRAPHENE_RECT_INIT (g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000),
+                                                      0,
+                                                      g_test_rand_double_range (-1000, 1000)));
+      break;
+
+    case 7:
+      /* a zero-height rect */
+      gsk_path_builder_add_rect (builder,
+                                 &GRAPHENE_RECT_INIT (g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000),
+                                                      0));
+      break;
+
+    case 8:
+      /* a negative-size rect */
+      gsk_path_builder_add_rect (builder,
+                                 &GRAPHENE_RECT_INIT (g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 0),
+                                                      g_test_rand_double_range (-1000, 0)));
+      break;
+
+    case 9:
+      /* an absolutely random rect */
+      gsk_path_builder_add_rect (builder,
+                                 &GRAPHENE_RECT_INIT (g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000)));
+      break;
+
+    case 10:
+      /* an absolutely random rect */
+      gsk_path_builder_add_rect (builder,
+                                 &GRAPHENE_RECT_INIT (g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000)));
+      break;
+
+    case 11:
+      /* an absolutely random circle */
+      gsk_path_builder_add_circle (builder,
+                                   &GRAPHENE_POINT_INIT (g_test_rand_double_range (-1000, 1000),
+                                                         g_test_rand_double_range (-1000, 1000)),
+                                   g_test_rand_double_range (1, 1000));
+      break;
+
+    case 12:
+      /* a zero-length line */
+      {
+        graphene_point_t point = GRAPHENE_POINT_INIT (g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000));
+        gsk_path_builder_move_to (builder, point.x, point.y);
+        gsk_path_builder_line_to (builder, point.x, point.y);
+      }
+      break;
+
+    case 13:
+      /* a curve with start == end */
+      {
+        graphene_point_t point = GRAPHENE_POINT_INIT (g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000));
+        gsk_path_builder_move_to (builder, point.x, point.y);
+        gsk_path_builder_cubic_to (builder,
+                                   g_test_rand_double_range (-1000, 1000),
+                                   g_test_rand_double_range (-1000, 1000),
+                                   g_test_rand_double_range (-1000, 1000),
+                                   g_test_rand_double_range (-1000, 1000),
+                                   point.x, point.y);
+      }
+      break;
+
+    case 14:
+      /* a conic with start == end */
+      {
+        graphene_point_t point = GRAPHENE_POINT_INIT (g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000));
+        gsk_path_builder_move_to (builder, point.x, point.y);
+        gsk_path_builder_conic_to (builder,
+                                   g_test_rand_double_range (-1000, 1000),
+                                   g_test_rand_double_range (-1000, 1000),
+                                   point.x, point.y,
+                                   random_weight ());
+      }
+      break;
+
+    case N_DEGENERATE_PATHS:
+    default:
+      g_assert_not_reached ();
+  }
+
+  return gsk_path_builder_free_to_path (builder);
+}
+
+static GskPath *
+create_random_path (guint max_contours);
+
+static void
+add_shape_contour (GskPathBuilder *builder)
+{
+#define N_SHAPE_CONTOURS 3
+  switch (g_test_rand_int_range (0, N_SHAPE_CONTOURS))
+  {
+    case 0:
+      gsk_path_builder_add_rect (builder,
+                                 &GRAPHENE_RECT_INIT (g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (1, 1000),
+                                                      g_test_rand_double_range (1, 1000)));
+      break;
+
+    case 1:
+      gsk_path_builder_add_circle (builder,
+                                   &GRAPHENE_POINT_INIT (g_test_rand_double_range (-1000, 1000),
+                                                         g_test_rand_double_range (-1000, 1000)),
+                                   g_test_rand_double_range (1, 1000));
+      break;
+
+    case 2:
+      {
+        GskPath *path = create_random_path (1);
+        gsk_path_builder_add_path (builder, path);
+        gsk_path_unref (path);
+      }
+      break;
+
+    case N_SHAPE_CONTOURS:
+    default:
+      g_assert_not_reached ();
+      break;
+  }
+}
+
+static void
+add_standard_contour (GskPathBuilder *builder)
+{
+  guint i, n;
+
+  if (g_test_rand_bit ())
+    {
+      if (g_test_rand_bit ())
+        gsk_path_builder_move_to (builder,
+                                  g_test_rand_double_range (-1000, 1000),
+                                  g_test_rand_double_range (-1000, 1000));
+      else
+        gsk_path_builder_rel_move_to (builder,
+                                      g_test_rand_double_range (-1000, 1000),
+                                      g_test_rand_double_range (-1000, 1000));
+    }
+
+  /* that 20 is random, but should be enough to get some
+   * crazy self-intersecting shapes */
+  n = g_test_rand_int_range (1, 20);
+  for (i = 0; i < n; i++)
+    {
+      switch (g_test_rand_int_range (0, 8))
+      {
+        case 0:
+          gsk_path_builder_line_to (builder,
+                                    g_test_rand_double_range (-1000, 1000),
+                                    g_test_rand_double_range (-1000, 1000));
+          break;
+
+        case 1:
+          gsk_path_builder_rel_line_to (builder,
+                                        g_test_rand_double_range (-1000, 1000),
+                                        g_test_rand_double_range (-1000, 1000));
+          break;
+
+        case 2:
+          gsk_path_builder_quad_to (builder,
+                                    g_test_rand_double_range (-1000, 1000),
+                                    g_test_rand_double_range (-1000, 1000),
+                                    g_test_rand_double_range (-1000, 1000),
+                                    g_test_rand_double_range (-1000, 1000));
+          break;
+
+        case 3:
+          gsk_path_builder_rel_quad_to (builder,
+                                        g_test_rand_double_range (-1000, 1000),
+                                        g_test_rand_double_range (-1000, 1000),
+                                        g_test_rand_double_range (-1000, 1000),
+                                        g_test_rand_double_range (-1000, 1000));
+          break;
+
+        case 4:
+          gsk_path_builder_cubic_to (builder,
+                                     g_test_rand_double_range (-1000, 1000),
+                                     g_test_rand_double_range (-1000, 1000),
+                                     g_test_rand_double_range (-1000, 1000),
+                                     g_test_rand_double_range (-1000, 1000),
+                                     g_test_rand_double_range (-1000, 1000),
+                                     g_test_rand_double_range (-1000, 1000));
+          break;
+
+        case 5:
+          gsk_path_builder_rel_cubic_to (builder,
+                                         g_test_rand_double_range (-1000, 1000),
+                                         g_test_rand_double_range (-1000, 1000),
+                                         g_test_rand_double_range (-1000, 1000),
+                                         g_test_rand_double_range (-1000, 1000),
+                                         g_test_rand_double_range (-1000, 1000),
+                                         g_test_rand_double_range (-1000, 1000));
+          break;
+
+        case 6:
+          gsk_path_builder_conic_to (builder,
+                                     g_test_rand_double_range (-1000, 1000),
+                                     g_test_rand_double_range (-1000, 1000),
+                                     g_test_rand_double_range (-1000, 1000),
+                                     g_test_rand_double_range (-1000, 1000),
+                                     random_weight ());
+          break;
+
+        case 7:
+          gsk_path_builder_rel_conic_to (builder,
+                                         g_test_rand_double_range (-1000, 1000),
+                                         g_test_rand_double_range (-1000, 1000),
+                                         g_test_rand_double_range (-1000, 1000),
+                                         g_test_rand_double_range (-1000, 1000),
+                                         random_weight ());
+          break;
+
+        default:
+          g_assert_not_reached();
+          break;
+      }
+    }
+
+  if (g_test_rand_bit ())
+    gsk_path_builder_close (builder);
+}
+
+static GskPath *
+create_random_path (guint max_contours)
+{
+  GskPathBuilder *builder;
+  guint i, n;
+
+  /* 5% chance for a weird shape */
+  if (!g_test_rand_int_range (0, 20))
+    return create_random_degenerate_path (max_contours);
+
+  builder = gsk_path_builder_new ();
+  n = g_test_rand_int_range (1, 10);
+  n = MIN (n, max_contours);
+
+  for (i = 0; i < n; i++)
+    {
+      /* 2/3 of shapes are standard contours */
+      if (g_test_rand_int_range (0, 3))
+        add_standard_contour (builder);
+      else
+        add_shape_contour (builder);
+    }
+
+  return gsk_path_builder_free_to_path (builder);
+}
+
+typedef struct {
+  GskPathOperation op;
+  graphene_point_t pts[4];
+  float weight;
+} PathOperation;
+
+static void
+test_segment_start (void)
+{
+  GskPath *path, *path1;
+  GskPathMeasure *measure, *measure1;
+  GskPathBuilder *builder;
+  float epsilon, length;
+  guint i;
+
+  path = create_random_path (G_MAXUINT);
+  measure = gsk_path_measure_new (path);
+  length = gsk_path_measure_get_length (measure);
+  epsilon = MAX (length / 1024, G_MINFLOAT);
+
+  for (i = 0; i < 100; i++)
+    {
+      float seg_length = length * i / 100.0f;
+
+      builder = gsk_path_builder_new ();
+      gsk_path_builder_add_segment (builder, measure, 0, seg_length);
+      path1 = gsk_path_builder_free_to_path (builder);
+      measure1 = gsk_path_measure_new (path1);
+
+      if (seg_length == 0)
+        g_assert_cmpfloat_with_epsilon (gsk_path_measure_get_length (measure), gsk_path_measure_get_length (measure1), epsilon);
+      else
+        g_assert_cmpfloat_with_epsilon (seg_length, gsk_path_measure_get_length (measure1), epsilon);
+
+      gsk_path_measure_unref (measure1);
+      gsk_path_unref (path1);
+    }
+
+  gsk_path_measure_unref (measure);
+  gsk_path_unref (path);
+}
+
+static void
+test_segment_end (void)
+{
+  GskPath *path, *path1;
+  GskPathMeasure *measure, *measure1;
+  GskPathBuilder *builder;
+  float epsilon, length;
+  guint i;
+
+  path = create_random_path (G_MAXUINT);
+  measure = gsk_path_measure_new (path);
+  length = gsk_path_measure_get_length (measure);
+  epsilon = MAX (length / 1024, G_MINFLOAT);
+
+  for (i = 0; i < 100; i++)
+    {
+      float seg_length = length * i / 100.0f;
+
+      builder = gsk_path_builder_new ();
+      gsk_path_builder_add_segment (builder, measure, length - seg_length, length);
+      path1 = gsk_path_builder_free_to_path (builder);
+      measure1 = gsk_path_measure_new (path1);
+
+      if (seg_length == 0)
+        g_assert_cmpfloat_with_epsilon (gsk_path_measure_get_length (measure), gsk_path_measure_get_length (measure1), epsilon);
+      else
+        g_assert_cmpfloat_with_epsilon (seg_length, gsk_path_measure_get_length (measure1), epsilon);
+
+      gsk_path_measure_unref (measure1);
+      gsk_path_unref (path1);
+    }
+
+  gsk_path_measure_unref (measure);
+  gsk_path_unref (path);
+}
+
+static void
+test_segment_chunk (void)
+{
+  GskPath *path, *path1, *path2;
+  GskPathMeasure *measure, *measure1, *measure2;
+  GskPathBuilder *builder;
+  float epsilon, length;
+  guint i;
+
+  path = create_random_path (G_MAXUINT);
+  measure = gsk_path_measure_new (path);
+  length = gsk_path_measure_get_length (measure);
+  epsilon = MAX (length / 1024, G_MINFLOAT);
+
+  for (i = 0; i <= 100; i++)
+    {
+      float seg_start = length * i / 200.0f;
+
+      builder = gsk_path_builder_new ();
+      gsk_path_builder_add_segment (builder, measure, seg_start, seg_start + length / 2);
+      path1 = gsk_path_builder_free_to_path (builder);
+      measure1 = gsk_path_measure_new (path1);
+
+      g_assert_cmpfloat_with_epsilon (length / 2, gsk_path_measure_get_length (measure1), epsilon);
+
+      builder = gsk_path_builder_new ();
+      gsk_path_builder_add_segment (builder, measure, seg_start + length / 2, seg_start);
+      path2 = gsk_path_builder_free_to_path (builder);
+      measure2 = gsk_path_measure_new (path2);
+
+      g_assert_cmpfloat_with_epsilon (length / 2, gsk_path_measure_get_length (measure2), epsilon);
+
+      gsk_path_measure_unref (measure2);
+      gsk_path_unref (path2);
+      gsk_path_measure_unref (measure1);
+      gsk_path_unref (path1);
+    }
+
+  gsk_path_measure_unref (measure);
+  gsk_path_unref (path);
+}
+
+static void
+test_segment (void)
+{
+  GskPath *path, *path1, *path2, *path3;
+  GskPathMeasure *measure, *measure1, *measure2, *measure3;
+  GskPathBuilder *builder;
+  guint i;
+  float split1, split2, epsilon, length;
+
+  for (i = 0; i < 1000; i++)
+    {
+      path = create_random_path (G_MAXUINT);
+      measure = gsk_path_measure_new (path);
+      length = gsk_path_measure_get_length (measure);
+      /* chosen high enough to stop the testsuite from failing */
+      epsilon = MAX (length / 64, 1.f / 1024);
+
+      split1 = g_test_rand_double_range (0, length);
+      split2 = g_test_rand_double_range (split1, length);
+
+      builder = gsk_path_builder_new ();
+      gsk_path_builder_add_segment (builder, measure, 0, split1);
+      path1 = gsk_path_builder_free_to_path (builder);
+      measure1 = gsk_path_measure_new (path1);
+
+      builder = gsk_path_builder_new ();
+      gsk_path_builder_add_segment (builder, measure, split1, split2);
+      path2 = gsk_path_builder_free_to_path (builder);
+      measure2 = gsk_path_measure_new (path2);
+
+      builder = gsk_path_builder_new ();
+      gsk_path_builder_add_segment (builder, measure, split2, length);
+      path3 = gsk_path_builder_free_to_path (builder);
+      measure3 = gsk_path_measure_new (path3);
+
+      g_assert_cmpfloat_with_epsilon (split1, gsk_path_measure_get_length (measure1), epsilon);
+      g_assert_cmpfloat_with_epsilon (split2 - split1, gsk_path_measure_get_length (measure2), epsilon);
+      g_assert_cmpfloat_with_epsilon (length - split2, gsk_path_measure_get_length (measure3), epsilon);
+
+      gsk_path_measure_unref (measure2);
+      gsk_path_measure_unref (measure1);
+      gsk_path_measure_unref (measure);
+      gsk_path_unref (path2);
+      gsk_path_unref (path1);
+      gsk_path_unref (path);
+    }
+}
+
+static void
+test_get_point (void)
+{
+  static const guint max_contours = 5;
+  static const float tolerance = 1.0;
+  GskPath *path;
+  GskPathMeasure *measure;
+  GskPathPoint point;
+  guint n_discontinuities;
+  float length, offset, last_offset;
+  graphene_point_t p, last_point;
+  guint i, j;
+  gboolean ret;
+
+  for (i = 0; i < 10; i++)
+    {
+      path = create_random_path (max_contours);
+      measure = gsk_path_measure_new_with_tolerance (path, tolerance);
+      length = gsk_path_measure_get_length (measure);
+      n_discontinuities = 0;
+
+      ret = gsk_path_measure_get_point (measure, 0, &point);
+      if (!ret)
+        {
+          g_assert_true (gsk_path_is_empty (path));
+          continue;
+        }
+      gsk_path_point_get_position (&point, &last_point);
+
+      /* FIXME: anything we can test with tangents here? */
+      last_offset = 0;
+
+      for (j = 1; j <= 1024; j++)
+        {
+          offset = length * j / 1024;
+          ret = gsk_path_measure_get_point (measure, offset, &point);
+          g_assert_true (ret);
+          gsk_path_point_get_position (&point, &p);
+
+          if (graphene_point_distance (&last_point, &p, NULL, NULL) > 2 * (offset - last_offset))
+            {
+              n_discontinuities++;
+              g_assert_cmpint (n_discontinuities, <, max_contours);
+            }
+
+          last_offset = offset;
+          last_point = p;
+        }
+
+      gsk_path_measure_unref (measure);
+      gsk_path_unref (path);
+    }
+}
+
+static void
+test_closest_point (void)
+{
+  static const float tolerance = 0.5;
+  GskPath *path, *path1, *path2;
+  GskPathMeasure *measure, *measure1, *measure2;
+  GskPathBuilder *builder;
+  GskPathPoint point;
+  guint i, j;
+  gboolean ret;
+
+  if (!g_test_slow ())
+    {
+      g_test_skip ("Skipping slow test");
+      return;
+    }
+
+  for (i = 0; i < 10; i++)
+    {
+      path1 = create_random_path (G_MAXUINT);
+      measure1 = gsk_path_measure_new_with_tolerance (path1, tolerance);
+      path2 = create_random_path (G_MAXUINT);
+      measure2 = gsk_path_measure_new_with_tolerance (path2, tolerance);
+
+      builder = gsk_path_builder_new ();
+      gsk_path_builder_add_path (builder, path1);
+      gsk_path_builder_add_path (builder, path2);
+      path = gsk_path_builder_free_to_path (builder);
+      measure = gsk_path_measure_new_with_tolerance (path, tolerance);
+
+      for (j = 0; j < 100; j++)
+        {
+          graphene_point_t test = GRAPHENE_POINT_INIT (g_test_rand_double_range (-1000, 1000),
+                                                       g_test_rand_double_range (-1000, 1000));
+          graphene_point_t p1, p2, p;
+          graphene_vec2_t t1, t2, t;
+          float offset1, offset2, offset;
+          float distance1, distance2, distance;
+
+          offset1 = offset2 = offset = 0;
+          distance1 = distance2 = distance = 0;
+          ret = gsk_path_get_closest_point (path1, &test, INFINITY, &point);
+          g_assert_true (ret);
+
+          gsk_path_point_get_position (&point, &p1);
+          gsk_path_point_get_tangent (&point, GSK_PATH_END, &t1);
+          offset1 = gsk_path_measure_get_distance (measure1, &point);
+          distance1 = graphene_point_distance (&p1, &test, NULL, NULL);
+
+          ret = gsk_path_get_closest_point (path2, &test, INFINITY, &point);
+          g_assert_true (ret);
+
+          gsk_path_point_get_position (&point, &p2);
+          gsk_path_point_get_tangent (&point, GSK_PATH_END, &t2);
+          offset2 = gsk_path_measure_get_distance (measure2, &point);
+          distance2 = graphene_point_distance (&p2, &test, NULL, NULL);
+
+          ret = gsk_path_get_closest_point (path, &test, INFINITY, &point);
+          g_assert_true (ret);
+
+          gsk_path_point_get_position (&point, &p);
+          gsk_path_point_get_tangent (&point, GSK_PATH_END, &t);
+          offset = gsk_path_measure_get_distance (measure, &point);
+          distance = graphene_point_distance (&p, &test, NULL, NULL);
+
+          if (distance1 == distance)
+            {
+              g_assert_cmpfloat (distance1, ==, distance);
+              g_assert_cmpfloat (p1.x, ==, p.x);
+              g_assert_cmpfloat (p1.y, ==, p.y);
+              g_assert_cmpfloat (offset1, ==, offset);
+              g_assert_true (graphene_vec2_equal (&t1, &t));
+            }
+          else
+            {
+              g_assert_cmpfloat (distance2, ==, distance);
+              g_assert_cmpfloat (p2.x, ==, p.x);
+              g_assert_cmpfloat (p2.y, ==, p.y);
+              g_assert_cmpfloat_with_epsilon (offset2 + gsk_path_measure_get_length (measure1), offset, MAX (G_MINFLOAT, offset / 1024));
+              g_assert_true (graphene_vec2_equal (&t2, &t));
+            }
+        }
+
+      gsk_path_measure_unref (measure2);
+      gsk_path_measure_unref (measure1);
+      gsk_path_measure_unref (measure);
+      gsk_path_unref (path2);
+      gsk_path_unref (path1);
+      gsk_path_unref (path);
+    }
+}
+
+static void
+test_closest_point_for_point (void)
+{
+  static const float tolerance = 0.5;
+  GskPath *path;
+  GskPathMeasure *measure;
+  GskPathPoint point;
+  float length, offset, distance;
+  graphene_point_t p, closest_point;
+  guint i, j;
+  gboolean ret;
+
+  if (!g_test_slow ())
+    {
+      g_test_skip ("Skipping slow test");
+      return;
+    }
+
+  for (i = 0; i < 100; i++)
+    {
+      path = create_random_path (G_MAXUINT);
+      if (gsk_path_is_empty (path))
+        {
+          /* empty paths have no closest point to anything */
+          gsk_path_unref (path);
+          continue;
+        }
+
+      measure = gsk_path_measure_new_with_tolerance (path, tolerance);
+      length = gsk_path_measure_get_length (measure);
+
+      for (j = 0; j < 100; j++)
+        {
+          offset = g_test_rand_double_range (0, length);
+          ret = gsk_path_measure_get_point (measure, offset, &point);
+          g_assert_true (ret);
+          gsk_path_point_get_position (&point, &p);
+          ret = gsk_path_get_closest_point (path, &p, 2 * tolerance, &point);
+          g_assert_true (ret);
+          gsk_path_point_get_position (&point, &closest_point);
+          //closest_offset = gsk_path_measure_get_distance (measure, &point);
+          distance = graphene_point_distance (&p, &closest_point, NULL, NULL);
+
+          /* should be given due to the TRUE return above, but who knows... */
+          g_assert_cmpfloat (distance, <=, 2 * tolerance);
+          g_assert_cmpfloat (graphene_point_distance (&p, &closest_point, NULL, NULL), <=, 2 * tolerance);
+          /* we can't check offsets here, since we might hit self-intersections
+          g_assert_cmpfloat_with_epsilon (closest_offset, offset, 2 * tolerance);
+          */
+        }
+
+      gsk_path_measure_unref (measure);
+      gsk_path_unref (path);
+    }
+}
+
+#define N_PATHS 3
+static void
+test_in_fill_union (void)
+{
+  GskPath *path;
+  GskPathMeasure *measure, *measures[N_PATHS];
+  GskPathBuilder *builder;
+  guint i, j, k;
+
+  for (i = 0; i < 100; i++)
+    {
+      builder = gsk_path_builder_new ();
+      for (k = 0; k < N_PATHS; k++)
+        {
+          path = create_random_path (G_MAXUINT);
+          measures[k] = gsk_path_measure_new (path);
+          gsk_path_builder_add_path (builder, path);
+          gsk_path_unref (path);
+        }
+      path = gsk_path_builder_free_to_path (builder);
+      measure = gsk_path_measure_new (path);
+      gsk_path_unref (path);
+
+      for (j = 0; j < 100; j++)
+        {
+          graphene_point_t test = GRAPHENE_POINT_INIT (g_test_rand_double_range (-1000, 1000),
+                                                       g_test_rand_double_range (-1000, 1000));
+          GskFillRule fill_rule;
+
+          for (fill_rule = GSK_FILL_RULE_WINDING; fill_rule <= GSK_FILL_RULE_EVEN_ODD; fill_rule++)
+            {
+              guint n_in_fill = 0;
+              gboolean in_fill;
+
+              for (k = 0; k < N_PATHS; k++)
+                {
+                  if (gsk_path_in_fill (gsk_path_measure_get_path (measures[k]), &test, GSK_FILL_RULE_EVEN_ODD))
+                    n_in_fill++;
+                }
+
+              in_fill = gsk_path_in_fill (gsk_path_measure_get_path (measure), &test, GSK_FILL_RULE_EVEN_ODD);
+
+              switch (fill_rule)
+              {
+                case GSK_FILL_RULE_WINDING:
+                  if (n_in_fill == 0)
+                    g_assert_false (in_fill);
+                  else if (n_in_fill == 1)
+                    g_assert_true (in_fill);
+                  /* else we can't say anything because the winding rule doesn't give enough info */
+                  break;
+
+                case GSK_FILL_RULE_EVEN_ODD:
+                  g_assert_cmpint (in_fill, ==, n_in_fill & 1);
+                  break;
+
+                default:
+                  g_assert_not_reached ();
+                  break;
+              }
+            }
+        }
+
+      gsk_path_measure_unref (measure);
+      for (k = 0; k < N_PATHS; k++)
+        {
+          gsk_path_measure_unref (measures[k]);
+        }
+    }
+}
+#undef N_PATHS
+
+/* This is somewhat sucky because using foreach breaks up the contours
+ * (like rects and circles) and replaces everything with the standard
+ * contour.
+ * But at least it extensively tests the standard contour.
+ */
+static gboolean
+rotate_path_cb (GskPathOperation        op,
+                const graphene_point_t *pts,
+                gsize                   n_pts,
+                float                   weight,
+                gpointer                user_data)
+{
+  GskPathBuilder **builders = user_data;
+
+  switch (op)
+  {
+    case GSK_PATH_MOVE:
+      gsk_path_builder_move_to (builders[0], pts[0].x, pts[0].y);
+      gsk_path_builder_move_to (builders[1], pts[0].y, -pts[0].x);
+      break;
+
+    case GSK_PATH_CLOSE:
+      gsk_path_builder_close (builders[0]);
+      gsk_path_builder_close (builders[1]);
+      break;
+
+    case GSK_PATH_LINE:
+      gsk_path_builder_line_to (builders[0], pts[1].x, pts[1].y);
+      gsk_path_builder_line_to (builders[1], pts[1].y, -pts[1].x);
+      break;
+
+    case GSK_PATH_QUAD:
+      gsk_path_builder_quad_to (builders[0], pts[1].x, pts[1].y, pts[2].x, pts[2].y);
+      gsk_path_builder_quad_to (builders[1], pts[1].y, -pts[1].x, pts[2].y, -pts[2].x);
+      break;
+
+    case GSK_PATH_CUBIC:
+      gsk_path_builder_cubic_to (builders[0], pts[1].x, pts[1].y, pts[2].x, pts[2].y, pts[3].x, pts[3].y);
+      gsk_path_builder_cubic_to (builders[1], pts[1].y, -pts[1].x, pts[2].y, -pts[2].x, pts[3].y, -pts[3].x);
+      break;
+
+    case GSK_PATH_CONIC:
+      gsk_path_builder_conic_to (builders[0], pts[1].x, pts[1].y, pts[2].x, pts[2].y, weight);
+      gsk_path_builder_conic_to (builders[1], pts[1].y, -pts[1].x, pts[2].y, -pts[2].x, weight);
+      break;
+
+    default:
+      g_assert_not_reached ();
+      return FALSE;
+  }
+
+  return TRUE;
+}
+
+static void
+test_in_fill_rotated (void)
+{
+  GskPath *path;
+  GskPathBuilder *builders[2];
+  GskPathMeasure *measures[2];
+  guint i, j;
+
+#define N_FILL_RULES 2
+  /* if this triggers, you added a new enum value to GskFillRule, so the define above needs
+   * an update */
+  g_assert_null (g_enum_get_value (g_type_class_ref (GSK_TYPE_FILL_RULE), N_FILL_RULES));
+
+  for (i = 0; i < 100; i++)
+    {
+      path = create_random_path (G_MAXUINT);
+      builders[0] = gsk_path_builder_new ();
+      builders[1] = gsk_path_builder_new ();
+      /* Use -1 here because we want all the flags, even future additions */
+      gsk_path_foreach (path, -1, rotate_path_cb, builders);
+      gsk_path_unref (path);
+
+      path = gsk_path_builder_free_to_path (builders[0]);
+      measures[0] = gsk_path_measure_new (path);
+      gsk_path_unref (path);
+      path = gsk_path_builder_free_to_path (builders[1]);
+      measures[1] = gsk_path_measure_new (path);
+      gsk_path_unref (path);
+
+      for (j = 0; j < 100; j++)
+        {
+          GskFillRule fill_rule = g_random_int_range (0, N_FILL_RULES);
+          float x = g_test_rand_double_range (-1000, 1000);
+          float y = g_test_rand_double_range (-1000, 1000);
+  
+          g_assert_cmpint (gsk_path_in_fill (gsk_path_measure_get_path (measures[0]), &GRAPHENE_POINT_INIT (x, y), fill_rule),
+                           ==,
+                           gsk_path_in_fill (gsk_path_measure_get_path (measures[1]), &GRAPHENE_POINT_INIT (y, -x), fill_rule));
+          g_assert_cmpint (gsk_path_in_fill (gsk_path_measure_get_path (measures[0]), &GRAPHENE_POINT_INIT (y, x), fill_rule),
+                           ==,
+                           gsk_path_in_fill (gsk_path_measure_get_path (measures[1]), &GRAPHENE_POINT_INIT (x, -y), fill_rule));
+        }
+
+      gsk_path_measure_unref (measures[0]);
+      gsk_path_measure_unref (measures[1]);
+    }
+#undef N_FILL_RULES
+}
+
+int
+main (int   argc,
+      char *argv[])
+{
+  gtk_test_init (&argc, &argv, NULL);
+
+  g_test_add_func ("/measure/segment_start", test_segment_start);
+  g_test_add_func ("/measure/segment_end", test_segment_end);
+  g_test_add_func ("/measure/segment_chunk", test_segment_chunk);
+  g_test_add_func ("/measure/segment", test_segment);
+  g_test_add_func ("/measure/get_point", test_get_point);
+  g_test_add_func ("/measure/closest_point", test_closest_point);
+  g_test_add_func ("/measure/closest_point_for_point", test_closest_point_for_point);
+  g_test_add_func ("/measure/in-fill-union", test_in_fill_union);
+  g_test_add_func ("/measure/in-fill-rotated", test_in_fill_rotated);
+
+  return g_test_run ();
+}

testsuite/gsk/meson.build

@@ -359,6 +359,11 @@ endforeach
 tests = [
   ['transform'],
   ['shader'],
+  ['path'],
+  ['path-special-cases'],
+  ['measure'],
+  ['measure-special-cases'],
+  ['dash'],
 ]
 
 test_cargs = []
@@ -389,6 +394,8 @@ foreach t : tests
 endforeach
 
 internal_tests = [
+  [ 'curve' ],
+  [ 'curve-special-cases' ],
   [ 'diff' ],
   [ 'half-float' ],
   ['rounded-rect'],

testsuite/gsk/path-special-cases.c

@@ -0,0 +1,320 @@
+/*
+ * 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 <gtk/gtk.h>
+
+/* testcases from path_parser.rs in librsvg */
+static void
+test_rsvg_parse (void)
+{
+  struct {
+    const char *in;
+    const char *out;
+  } tests[] = {
+    { "", "" },
+    // numbers
+    { "M 10 20", "M 10 20" },
+    { "M -10 -20", "M -10 -20" },
+    { "M .10 0.20", "M 0.1 0.2" },
+    { "M -.10 -0.20", "M -0.1 -0.2" },
+    { "M-.10-0.20", "M -0.1 -0.2" },
+    { "M10.5.50", "M 10.5 0.5" },
+    { "M.10.20", "M 0.1 0.2" },
+    { "M .10E1 .20e-4", "M 1 2e-05" },
+    { "M-.10E1-.20", "M -1 -0.2" },
+    { "M10.10E2 -0.20e3", "M 1010 -200" },
+    { "M-10.10E2-0.20e-3", "M -1010 -0.0002" },
+    { "M1e2.5", "M 100 0.5" },
+    { "M1e-2.5", "M 0.01 0.5" },
+    { "M1e+2.5", "M 100 0.5" },
+    // bogus numbers
+    { "M+", NULL },
+    { "M-", NULL },
+    { "M+x", NULL },
+    { "M10e", NULL },
+    { "M10ex", NULL },
+    { "M10e-", NULL },
+    { "M10e+x", NULL },
+    // numbers with comma
+    { "M 10, 20", "M 10 20" },
+    { "M -10,-20", "M -10 -20" },
+    { "M.10    ,     0.20", "M 0.1 0.2" },
+    { "M -.10, -0.20   ", "M -0.1 -0.2" },
+    { "M-.10-0.20", "M -0.1 -0.2" },
+    { "M.10.20", "M 0.1 0.2" },
+    { "M .10E1,.20e-4", "M 1 2e-05" },
+    { "M-.10E-2,-.20", "M -0.001 -0.2" },
+    { "M10.10E2,-0.20e3", "M 1010 -200" },
+    { "M-10.10E2,-0.20e-3", "M -1010 -0.0002" },
+    // single moveto
+    { "M 10 20 ", "M 10 20" },
+    { "M10,20  ", "M 10 20" },
+    { "M10 20   ", "M 10 20" },
+    { "    M10,20     ", "M 10 20" },
+    // relative moveto
+    { "m10 20", "M 10 20" },
+    // absolute moveto with implicit lineto
+    { "M10 20 30 40", "M 10 20 L 30 40" },
+    { "M10,20,30,40", "M 10 20 L 30 40" },
+    { "M.1-2,3E2-4", "M 0.1 -2 L 300 -4" },
+    // relative moveto with implicit lineto
+    { "m10 20 30 40", "M 10 20 L 40 60" },
+    // relative moveto with relative lineto sequence
+    { "m 46,447 l 0,0.5 -1,0 -1,0 0,1 0,12",
+      "M 46 447 L 46 447.5 L 45 447.5 L 44 447.5 L 44 448.5 L 44 460.5" },
+    // absolute moveto with implicit linetos
+    { "M10,20 30,40,50 60", "M 10 20 L 30 40 L 50 60" },
+    // relative moveto with implicit linetos
+    { "m10 20 30 40 50 60", "M 10 20 L 40 60 L 90 120" },
+    // absolute moveto moveto
+    { "M10 20 M 30 40", "M 10 20 M 30 40" },
+    // relative moveto moveto
+    { "m10 20 m 30 40", "M 10 20 M 40 60" },
+    // relative moveto lineto moveto
+    { "m10 20 30 40 m 50 60", "M 10 20 L 40 60 M 90 120" },
+    // absolute moveto lineto
+    { "M10 20 L30,40", "M 10 20 L 30 40" },
+    // relative moveto lineto
+    { "m10 20 l30,40", "M 10 20 L 40 60" },
+    // relative moveto lineto lineto abs lineto
+    { "m10 20 30 40l30,40,50 60L200,300",
+      "M 10 20 L 40 60 L 70 100 L 120 160 L 200 300" },
+    // horizontal lineto
+    { "M10 20 H30", "M 10 20 L 30 20" },
+    { "M 10 20 H 30 40",  "M 10 20 L 30 20 L 40 20" },
+    { "M10 20 H30,40-50", "M 10 20 L 30 20 L 40 20 L -50 20" },
+    { "m10 20 h30,40-50", "M 10 20 L 40 20 L 80 20 L 30 20" },
+    // vertical lineto
+    { "M10 20 V30", "M 10 20 L 10 30" },
+    { "M10 20 V30 40", "M 10 20 L 10 30 L 10 40" },
+    { "M10 20 V30,40-50", "M 10 20 L 10 30 L 10 40 L 10 -50" },
+    { "m10 20 v30,40-50", "M 10 20 L 10 50 L 10 90 L 10 40" },
+    // curveto
+    { "M10 20 C 30,40 50 60-70,80", "M 10 20 C 30 40, 50 60, -70 80" },
+    { "M10 20 C 30,40 50 60-70,80,90 100,110 120,130,140",
+      "M 10 20 C 30 40, 50 60, -70 80 C 90 100, 110 120, 130 140" },
+    { "m10 20 c 30,40 50 60-70,80,90 100,110 120,130,140",
+      "M 10 20 C 40 60, 60 80, -60 100 C 30 200, 50 220, 70 240" },
+    { "m10 20 c 30,40 50 60-70,80 90 100,110 120,130,140",
+      "M 10 20 C 40 60, 60 80, -60 100 C 30 200, 50 220, 70 240" },
+    // smooth curveto
+    { "M10 20 S 30,40-50,60", "M 10 20 C 10 20, 30 40, -50 60" },
+    { "M10 20 S 30,40 50 60-70,80,90 100",
+      "M 10 20 C 10 20, 30 40, 50 60 C 70 80, -70 80, 90 100" },
+    // quadratic curveto
+    { "M10 20 Q30 40 50 60", "M 10 20 Q 30 40, 50 60" },
+    { "M10 20 Q30 40 50 60,70,80-90 100",
+      "M 10 20 Q 30 40, 50 60 Q 70 80, -90 100" },
+    { "m10 20 q 30,40 50 60-70,80 90 100",
+      "M 10 20 Q 40 60, 60 80 Q -10 160, 150 180" },
+    // smooth quadratic curveto
+    { "M10 20 T30 40", "M 10 20 Q 10 20, 30 40" },
+    { "M10 20 Q30 40 50 60 T70 80", "M 10 20 Q 30 40, 50 60 Q 70 80, 70 80" },
+    { "m10 20 q 30,40 50 60t-70,80",
+      "M 10 20 Q 40 60, 60 80 Q 80 100, -10 160" },
+    // elliptical arc. Exact numbers depend on too much math, so just verify
+    // that these parse successfully
+    { "M 1 3 A 1 2 3 00 6 7", "path" },
+    { "M 1 2 A 1 2 3 016 7", "path" },
+    { "M 1 2 A 1 2 3 10,6 7", "path" },
+    { "M 1 2 A 1 2 3 1,1 6 7", "path" },
+    { "M 1 2 A 1 2 3 1 1 6 7", "path" },
+    { "M 1 2 A 1 2 3 1 16 7", "path" },
+    // close path
+    { "M10 20 Z", "M 10 20 Z" },
+    { "m10 20 30 40 m 50 60 70 80 90 100z", "M 10 20 L 40 60 M 90 120 L 160 200 L 250 300 Z" },
+    // must start with moveto
+    { " L10 20", NULL },
+    // moveto args
+    { "M", NULL },
+    { "M,", NULL },
+    { "M10", NULL },
+    { "M10,", NULL },
+    { "M10x", NULL },
+    { "M10,x", NULL },
+    { "M10-20,", NULL },
+    { "M10-20-30", NULL },
+    { "M10-20-30 x", NULL },
+    // closepath args
+    { "M10-20z10", NULL },
+    { "M10-20z,", NULL },
+    // lineto args
+    { "M10-20L10", NULL },
+    { "M 10,10 L 20,20,30", NULL },
+    { "M 10,10 L 20,20,", NULL },
+    // horizontal lineto args
+    { "M10-20H", NULL },
+    { "M10-20H,", NULL },
+    { "M10-20H30,", NULL },
+    // vertical lineto args
+    { "M10-20v", NULL },
+    { "M10-20v,", NULL },
+    { "M10-20v30,", NULL },
+    // curveto args
+    { "M10-20C1", NULL },
+    { "M10-20C1,", NULL },
+    { "M10-20C1 2", NULL },
+    { "M10-20C1,2,", NULL },
+    { "M10-20C1 2 3", NULL },
+    { "M10-20C1,2,3", NULL },
+    { "M10-20C1,2,3,", NULL },
+    { "M10-20C1 2 3 4", NULL },
+    { "M10-20C1,2,3,4", NULL },
+    { "M10-20C1,2,3,4,", NULL },
+    { "M10-20C1 2 3 4 5", NULL },
+    { "M10-20C1,2,3,4,5", NULL },
+    { "M10-20C1,2,3,4,5,", NULL },
+    { "M10-20C1,2,3,4,5,6,", NULL },
+    // smooth curveto args
+    { "M10-20S1", NULL },
+    { "M10-20S1,", NULL },
+    { "M10-20S1 2", NULL },
+    { "M10-20S1,2,", NULL },
+    { "M10-20S1 2 3", NULL },
+    { "M10-20S1,2,3,", NULL },
+    { "M10-20S1,2,3,4,", NULL },
+    // quadratic curveto args
+    { "M10-20Q1", NULL },
+    { "M10-20Q1,", NULL },
+    { "M10-20Q1 2", NULL },
+    { "M10-20Q1,2,", NULL },
+    { "M10-20Q1 2 3", NULL },
+    { "M10-20Q1,2,3", NULL },
+    { "M10-20Q1,2,3,", NULL },
+    { "M10 20 Q30 40 50 60,", NULL },
+    // smooth quadratic curveto args
+    { "M10-20T1", NULL },
+    { "M10-20T1,", NULL },
+    { "M10 20 T 30 40,", NULL },
+    // elliptical arc args
+    { "M10-20A1", NULL },
+    { "M10-20A1,", NULL },
+    { "M10-20A1 2", NULL },
+    { "M10-20A1 2,", NULL },
+    { "M10-20A1 2 3", NULL },
+    { "M10-20A1 2 3,", NULL },
+    { "M10-20A1 2 3 4", NULL },
+    { "M10-20A1 2 3 1", NULL },
+    { "M10-20A1 2 3,1,", NULL },
+    { "M10-20A1 2 3 1 5", NULL },
+    { "M10-20A1 2 3 1 1", NULL },
+    { "M10-20A1 2 3,1,1,", NULL },
+    { "M10-20A1 2 3 1 1 6", NULL },
+    { "M10-20A1 2 3,1,1,6,", NULL },
+    { "M 1 2 A 1 2 3 1.0 0.0 6 7", NULL },
+    { "M10-20A1 2 3,1,1,6,7,", NULL },
+    // misc
+    { "M.. 1,0 0,100000", NULL },
+    { "M 10 20,M 10 20", NULL },
+    { "M 10 20, M 10 20", NULL },
+    { "M 10 20, M 10 20", NULL },
+    { "M 10 20, ", NULL },
+  };
+  int i;
+
+  for (i = 0; i < G_N_ELEMENTS (tests); i++)
+    {
+      GskPath *path;
+      char *string;
+      char *string2;
+
+      if (g_test_verbose ())
+        g_print ("%d: %s\n", i, tests[i].in);
+
+      path = gsk_path_parse (tests[i].in);
+      if (tests[i].out)
+        {
+          g_assert_nonnull (path);
+          string = gsk_path_to_string (path);
+          gsk_path_unref (path);
+
+          if (strcmp (tests[i].out, "path") != 0)
+            {
+              /* Preferred, but doesn't work, because gsk_path_print()
+               * prints numbers with insane accuracy
+               */
+              /* g_assert_cmpstr (tests[i].out, ==, string); */
+              path = gsk_path_parse (tests[i].out);
+              g_assert_nonnull (path);
+
+              string2 = gsk_path_to_string (path);
+              gsk_path_unref (path);
+
+              g_assert_cmpstr (string, ==, string2);
+
+              g_free (string2);
+            }
+
+          path = gsk_path_parse (string);
+          g_assert_nonnull (path);
+
+          string2 = gsk_path_to_string (path);
+          gsk_path_unref (path);
+
+          g_assert_cmpstr (string, ==, string2);
+
+          g_free (string);
+          g_free (string2);
+        }
+      else
+        g_assert_null (path);
+    }
+}
+
+/* Test that circles and rectangles serialize as expected and can be
+ * round-tripped through strings.
+ */
+static void
+test_serialize_custom_contours (void)
+{
+  GskPathBuilder *builder;
+  GskPath *path;
+  GskPath *path1;
+  char *string;
+  char *string1;
+
+  builder = gsk_path_builder_new ();
+  gsk_path_builder_add_circle (builder, &GRAPHENE_POINT_INIT (100, 100), 50);
+  gsk_path_builder_add_rect (builder, &GRAPHENE_RECT_INIT (111, 222, 333, 444));
+  path = gsk_path_builder_free_to_path (builder);
+
+  string = gsk_path_to_string (path);
+  g_assert_cmpstr ("M 150 100 A 50 50 0 0 0 50 100 A 50 50 0 0 0 150 100 z M 111 222 h 333 v 444 h -333 z", ==, string);
+
+  path1 = gsk_path_parse (string);
+  string1 = gsk_path_to_string (path1);
+  g_assert_cmpstr (string, ==, string1);
+
+  g_free (string);
+  g_free (string1);
+  gsk_path_unref (path);
+  gsk_path_unref (path1);
+}
+
+int
+main (int   argc,
+      char *argv[])
+{
+  gtk_test_init (&argc, &argv, NULL);
+
+  g_test_add_func ("/path/rsvg-parse", test_rsvg_parse);
+  g_test_add_func ("/path/serialize-custom-contours", test_serialize_custom_contours);
+
+  return g_test_run ();
+}

testsuite/gsk/path.c

@@ -0,0 +1,654 @@
+/*
+ * 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 <gtk/gtk.h>
+
+static float
+random_weight (void)
+{
+  if (g_test_rand_bit ())
+    return g_test_rand_double_range (1, 20);
+  else
+    return 1.0 / g_test_rand_double_range (1, 20);
+}
+
+static GskPath *
+create_random_degenerate_path (guint max_contours)
+{
+#define N_DEGENERATE_PATHS 15
+  GskPathBuilder *builder;
+  guint i;
+
+  builder = gsk_path_builder_new ();
+
+  switch (g_test_rand_int_range (0, N_DEGENERATE_PATHS))
+  {
+    case 0:
+      /* empty path */
+      break;
+
+    case 1:
+      /* a single point */
+      gsk_path_builder_move_to (builder, 
+                                g_test_rand_double_range (-1000, 1000),
+                                g_test_rand_double_range (-1000, 1000));
+      break;
+
+    case 2:
+      /* N points */
+      for (i = 0; i < MIN (10, max_contours); i++)
+        {
+          gsk_path_builder_move_to (builder, 
+                                    g_test_rand_double_range (-1000, 1000),
+                                    g_test_rand_double_range (-1000, 1000));
+        }
+      break;
+
+    case 3:
+      /* 1 closed point */
+      gsk_path_builder_move_to (builder, 
+                                g_test_rand_double_range (-1000, 1000),
+                                g_test_rand_double_range (-1000, 1000));
+      gsk_path_builder_close (builder);
+      break;
+
+    case 4:
+      /* the same point closed N times */
+      gsk_path_builder_move_to (builder, 
+                                g_test_rand_double_range (-1000, 1000),
+                                g_test_rand_double_range (-1000, 1000));
+      for (i = 0; i < MIN (10, max_contours); i++)
+        {
+          gsk_path_builder_close (builder);
+        }
+      break;
+
+    case 5:
+      /* a zero-width and zero-height rect */
+      gsk_path_builder_add_rect (builder,
+                                 &GRAPHENE_RECT_INIT (g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000),
+                                                      0, 0));
+      break;
+
+    case 6:
+      /* a zero-width rect */
+      gsk_path_builder_add_rect (builder,
+                                 &GRAPHENE_RECT_INIT (g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000),
+                                                      0,
+                                                      g_test_rand_double_range (-1000, 1000)));
+      break;
+
+    case 7:
+      /* a zero-height rect */
+      gsk_path_builder_add_rect (builder,
+                                 &GRAPHENE_RECT_INIT (g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000),
+                                                      0));
+      break;
+
+    case 8:
+      /* a negative-size rect */
+      gsk_path_builder_add_rect (builder,
+                                 &GRAPHENE_RECT_INIT (g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 0),
+                                                      g_test_rand_double_range (-1000, 0)));
+      break;
+
+    case 9:
+      /* an absolutely random rect */
+      gsk_path_builder_add_rect (builder,
+                                 &GRAPHENE_RECT_INIT (g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000)));
+      break;
+
+    case 10:
+      /* an absolutely random rect */
+      gsk_path_builder_add_rect (builder,
+                                 &GRAPHENE_RECT_INIT (g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000)));
+      break;
+
+    case 11:
+      /* an absolutely random circle */
+      gsk_path_builder_add_circle (builder,
+                                   &GRAPHENE_POINT_INIT (g_test_rand_double_range (-1000, 1000),
+                                                         g_test_rand_double_range (-1000, 1000)),
+                                   g_test_rand_double_range (1, 1000));
+      break;
+
+    case 12:
+      /* a zero-length line */
+      {
+        graphene_point_t point = GRAPHENE_POINT_INIT (g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000));
+        gsk_path_builder_move_to (builder, point.x, point.y);
+        gsk_path_builder_line_to (builder, point.x, point.y);
+      }
+      break;
+
+    case 13:
+      /* a curve with start == end */
+      {
+        graphene_point_t point = GRAPHENE_POINT_INIT (g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000));
+        gsk_path_builder_move_to (builder, point.x, point.y);
+        gsk_path_builder_cubic_to (builder,
+                                   g_test_rand_double_range (-1000, 1000),
+                                   g_test_rand_double_range (-1000, 1000),
+                                   g_test_rand_double_range (-1000, 1000),
+                                   g_test_rand_double_range (-1000, 1000),
+                                   point.x, point.y);
+      }
+      break;
+
+    case 14:
+      /* a conic with start == end */
+      {
+        graphene_point_t point = GRAPHENE_POINT_INIT (g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000));
+        gsk_path_builder_move_to (builder, point.x, point.y);
+        gsk_path_builder_conic_to (builder,
+                                   g_test_rand_double_range (-1000, 1000),
+                                   g_test_rand_double_range (-1000, 1000),
+                                   point.x, point.y,
+                                   random_weight ());
+      }
+      break;
+
+    case N_DEGENERATE_PATHS:
+    default:
+      g_assert_not_reached ();
+  }
+
+  return gsk_path_builder_free_to_path (builder);
+}
+
+static GskPath *
+create_random_path (guint max_contours);
+
+static void
+add_shape_contour (GskPathBuilder *builder)
+{
+#define N_SHAPE_CONTOURS 3
+  switch (g_test_rand_int_range (0, N_SHAPE_CONTOURS))
+  {
+    case 0:
+      gsk_path_builder_add_rect (builder,
+                                 &GRAPHENE_RECT_INIT (g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (-1000, 1000),
+                                                      g_test_rand_double_range (1, 1000),
+                                                      g_test_rand_double_range (1, 1000)));
+      break;
+
+    case 1:
+      gsk_path_builder_add_circle (builder,
+                                   &GRAPHENE_POINT_INIT (g_test_rand_double_range (-1000, 1000),
+                                                         g_test_rand_double_range (-1000, 1000)),
+                                   g_test_rand_double_range (1, 1000));
+      break;
+
+    case 2:
+      {
+        GskPath *path = create_random_path (1);
+        gsk_path_builder_add_path (builder, path);
+        gsk_path_unref (path);
+      }
+      break;
+
+    case N_SHAPE_CONTOURS:
+    default:
+      g_assert_not_reached ();
+      break;
+  }
+}
+
+static void
+add_standard_contour (GskPathBuilder *builder)
+{
+  guint i, n;
+
+  if (g_test_rand_bit ())
+    {
+      if (g_test_rand_bit ())
+        gsk_path_builder_move_to (builder,
+                                  g_test_rand_double_range (-1000, 1000),
+                                  g_test_rand_double_range (-1000, 1000));
+      else
+        gsk_path_builder_rel_move_to (builder,
+                                      g_test_rand_double_range (-1000, 1000),
+                                      g_test_rand_double_range (-1000, 1000));
+    }
+
+  /* that 20 is random, but should be enough to get some
+   * crazy self-intersecting shapes */
+  n = g_test_rand_int_range (1, 20);
+  for (i = 0; i < n; i++)
+    {
+      switch (g_test_rand_int_range (0, 8))
+      {
+        case 0:
+          gsk_path_builder_line_to (builder,
+                                    g_test_rand_double_range (-1000, 1000),
+                                    g_test_rand_double_range (-1000, 1000));
+          break;
+
+        case 1:
+          gsk_path_builder_rel_line_to (builder,
+                                        g_test_rand_double_range (-1000, 1000),
+                                        g_test_rand_double_range (-1000, 1000));
+          break;
+
+        case 2:
+          gsk_path_builder_quad_to (builder,
+                                    g_test_rand_double_range (-1000, 1000),
+                                    g_test_rand_double_range (-1000, 1000),
+                                    g_test_rand_double_range (-1000, 1000),
+                                    g_test_rand_double_range (-1000, 1000));
+          break;
+
+        case 3:
+          gsk_path_builder_rel_quad_to (builder,
+                                        g_test_rand_double_range (-1000, 1000),
+                                        g_test_rand_double_range (-1000, 1000),
+                                        g_test_rand_double_range (-1000, 1000),
+                                        g_test_rand_double_range (-1000, 1000));
+          break;
+
+        case 4:
+          gsk_path_builder_cubic_to (builder,
+                                     g_test_rand_double_range (-1000, 1000),
+                                     g_test_rand_double_range (-1000, 1000),
+                                     g_test_rand_double_range (-1000, 1000),
+                                     g_test_rand_double_range (-1000, 1000),
+                                     g_test_rand_double_range (-1000, 1000),
+                                     g_test_rand_double_range (-1000, 1000));
+          break;
+
+        case 5:
+          gsk_path_builder_rel_cubic_to (builder,
+                                         g_test_rand_double_range (-1000, 1000),
+                                         g_test_rand_double_range (-1000, 1000),
+                                         g_test_rand_double_range (-1000, 1000),
+                                         g_test_rand_double_range (-1000, 1000),
+                                         g_test_rand_double_range (-1000, 1000),
+                                         g_test_rand_double_range (-1000, 1000));
+          break;
+
+        case 6:
+          gsk_path_builder_conic_to (builder,
+                                     g_test_rand_double_range (-1000, 1000),
+                                     g_test_rand_double_range (-1000, 1000),
+                                     g_test_rand_double_range (-1000, 1000),
+                                     g_test_rand_double_range (-1000, 1000),
+                                     random_weight ());
+          break;
+
+        case 7:
+          gsk_path_builder_rel_conic_to (builder,
+                                         g_test_rand_double_range (-1000, 1000),
+                                         g_test_rand_double_range (-1000, 1000),
+                                         g_test_rand_double_range (-1000, 1000),
+                                         g_test_rand_double_range (-1000, 1000),
+                                         random_weight ());
+          break;
+
+        default:
+          g_assert_not_reached();
+          break;
+      }
+    }
+
+  if (g_test_rand_bit ())
+    gsk_path_builder_close (builder);
+}
+
+static GskPath *
+create_random_path (guint max_contours)
+{
+  GskPathBuilder *builder;
+  guint i, n;
+
+  /* 5% chance for a weird shape */
+  if (!g_test_rand_int_range (0, 20))
+    return create_random_degenerate_path (max_contours);
+
+  builder = gsk_path_builder_new ();
+  n = g_test_rand_int_range (1, 10);
+  n = MIN (n, max_contours);
+
+  for (i = 0; i < n; i++)
+    {
+      /* 2/3 of shapes are standard contours */
+      if (g_test_rand_int_range (0, 3))
+        add_standard_contour (builder);
+      else
+        add_shape_contour (builder);
+    }
+
+  return gsk_path_builder_free_to_path (builder);
+}
+
+typedef struct {
+  GskPathOperation op;
+  graphene_point_t pts[4];
+  float weight;
+} PathOperation;
+
+static void
+_g_string_append_double (GString *string,
+                         double   d)
+{
+  char buf[G_ASCII_DTOSTR_BUF_SIZE];
+
+  g_ascii_dtostr (buf, G_ASCII_DTOSTR_BUF_SIZE, d);
+  g_string_append (string, buf);
+}
+
+static void
+_g_string_append_point (GString                *string,
+                        const graphene_point_t *pt)
+{
+  _g_string_append_double (string, pt->x);
+  g_string_append_c (string, ' ');
+  _g_string_append_double (string, pt->y);
+}
+
+static void
+path_operation_print (const PathOperation *p,
+                      GString             *string)
+{
+  switch (p->op)
+  {
+    case GSK_PATH_MOVE:
+      g_string_append (string, "M ");
+      _g_string_append_point (string, &p->pts[0]);
+      break;
+
+    case GSK_PATH_CLOSE:
+      g_string_append (string, " Z");
+      break;
+
+    case GSK_PATH_LINE:
+      g_string_append (string, " L ");
+      _g_string_append_point (string, &p->pts[1]);
+      break;
+
+    case GSK_PATH_QUAD:
+      g_string_append (string, " Q ");
+      _g_string_append_point (string, &p->pts[1]);
+      g_string_append (string, ", ");
+      _g_string_append_point (string, &p->pts[2]);
+      break;
+
+    case GSK_PATH_CUBIC:
+      g_string_append (string, " C ");
+      _g_string_append_point (string, &p->pts[1]);
+      g_string_append (string, ", ");
+      _g_string_append_point (string, &p->pts[2]);
+      g_string_append (string, ", ");
+      _g_string_append_point (string, &p->pts[3]);
+      break;
+
+    case GSK_PATH_CONIC:
+      /* This is not valid SVG */
+      g_string_append (string, " O ");
+      _g_string_append_point (string, &p->pts[1]);
+      g_string_append (string, ", ");
+      _g_string_append_point (string, &p->pts[2]);
+      g_string_append (string, ", ");
+      _g_string_append_double (string, p->weight);
+      break;
+
+    default:
+      g_assert_not_reached();
+      return;
+  }
+}
+
+static gboolean
+path_operation_equal (const PathOperation *p1,
+                      const PathOperation *p2,
+                      float                epsilon)
+{
+  if (p1->op != p2->op)
+    return FALSE;
+
+  /* No need to compare pts[0] for most ops, that's just
+   * duplicate work. */
+  switch (p1->op)
+    {
+      case GSK_PATH_MOVE:
+        return graphene_point_near (&p1->pts[0], &p2->pts[0], epsilon);
+
+      case GSK_PATH_LINE:
+      case GSK_PATH_CLOSE:
+        return graphene_point_near (&p1->pts[1], &p2->pts[1], epsilon);
+
+      case GSK_PATH_QUAD:
+        return graphene_point_near (&p1->pts[1], &p2->pts[1], epsilon)
+            && graphene_point_near (&p1->pts[2], &p2->pts[2], epsilon);
+
+      case GSK_PATH_CUBIC:
+        return graphene_point_near (&p1->pts[1], &p2->pts[1], epsilon)
+            && graphene_point_near (&p1->pts[2], &p2->pts[2], epsilon)
+            && graphene_point_near (&p1->pts[3], &p2->pts[3], epsilon);
+
+      case GSK_PATH_CONIC:
+        return graphene_point_near (&p1->pts[1], &p2->pts[1], epsilon)
+            && graphene_point_near (&p1->pts[2], &p2->pts[2], epsilon)
+            && G_APPROX_VALUE (p1->weight, p2->weight, epsilon);
+
+      default:
+        g_return_val_if_reached (FALSE);
+    }
+}
+
+static gboolean 
+collect_path_operation_cb (GskPathOperation        op,
+                           const graphene_point_t *pts,
+                           gsize                   n_pts,
+                           float                   weight,
+                           gpointer                user_data)
+{
+  g_array_append_vals (user_data,
+                       (PathOperation[1])  { {
+                         op,
+                         {
+                           GRAPHENE_POINT_INIT(pts[0].x, pts[0].y),
+                           GRAPHENE_POINT_INIT(n_pts > 1 ? pts[1].x : 0,
+                                               n_pts > 1 ? pts[1].y : 0),
+                           GRAPHENE_POINT_INIT(n_pts > 2 ? pts[2].x : 0,
+                                               n_pts > 2 ? pts[2].y : 0),
+                           GRAPHENE_POINT_INIT(n_pts > 3 ? pts[3].x : 0,
+                                               n_pts > 3 ? pts[3].y : 0)
+                         },
+                         weight
+                       } },
+                       1);
+  return TRUE;
+}
+
+static GArray *
+collect_path (GskPath *path)
+{
+  GArray *array = g_array_new (FALSE, FALSE, sizeof (PathOperation));
+
+  /* Use -1 here because we want all the flags, even future additions */
+  gsk_path_foreach (path, -1, collect_path_operation_cb, array);
+
+  return array;
+}
+
+static void
+assert_path_equal_func (const char *domain,
+                        const char *file,
+                        int         line,
+                        const char *func,
+                        GskPath    *path1,
+                        GskPath    *path2,
+                        float       epsilon)
+{
+  GArray *ops1, *ops2;
+  guint i;
+
+  ops1 = collect_path (path1);
+  ops2 = collect_path (path2);
+
+  for (i = 0; i < MAX (ops1->len, ops2->len); i++)
+    {
+      PathOperation *op1 = i < ops1->len ? &g_array_index (ops1, PathOperation, i) : NULL;
+      PathOperation *op2 = i < ops2->len ? &g_array_index (ops2, PathOperation, i) : NULL;
+
+      if (op1 == NULL || op2 == NULL || !path_operation_equal (op1, op2, epsilon))
+        {
+          GString *string;
+          guint j;
+
+          /* Find the operation we start to print */
+          for (j = i; j-- > 0; )
+            {
+              PathOperation *op = &g_array_index (ops1, PathOperation, j);
+              if (op->op == GSK_PATH_MOVE)
+                break;
+              if (j + 3 == i)
+                {
+                  j = i - 1;
+                  break;
+                }
+            }
+
+          string = g_string_new (j == 0 ? "" : "... ");
+          for (; j < i; j++)
+            {
+              PathOperation *op = &g_array_index (ops1, PathOperation, j);
+              path_operation_print (op, string);
+              g_string_append_c (string, ' ');
+            }
+
+          g_string_append (string, "\\\n    ");
+          if (op1)
+            {
+              path_operation_print (op1, string);
+              if (ops1->len > i + 1)
+                g_string_append (string, " ...");
+            }
+          g_string_append (string, "\n    ");
+          if (op1)
+            {
+              path_operation_print (op2, string);
+              if (ops2->len > i + 1)
+                g_string_append (string, " ...");
+            }
+
+          g_assertion_message (domain, file, line, func, string->str);
+
+          g_string_free (string, TRUE);
+        }
+    }
+
+  g_array_free (ops1, TRUE);
+  g_array_free (ops2, TRUE);
+}
+#define assert_path_equal(p1,p2) assert_path_equal_func(G_LOG_DOMAIN, __FILE__, __LINE__, G_STRFUNC, (p1),(p2), FLOAT_EPSILON)
+#define assert_path_equal_with_epsilon(p1,p2, epsilon) \
+    assert_path_equal_func(G_LOG_DOMAIN, __FILE__, __LINE__, G_STRFUNC, (p1),(p2), (epsilon))
+
+static void
+test_create (void)
+{
+  GskPath *path1, *path2, *built;
+  GskPathBuilder *builder;
+  guint i;
+  char *s;
+  GString *str;
+
+  for (i = 0; i < 1000; i++)
+    {
+      builder = gsk_path_builder_new ();
+      path1 = create_random_path (G_MAXUINT);
+      gsk_path_builder_add_path (builder, path1);
+      path2 = create_random_path (G_MAXUINT);
+      gsk_path_builder_add_path (builder, path2);
+      built = gsk_path_builder_free_to_path (builder);
+
+      str = g_string_new (NULL);
+      gsk_path_print (path1, str);
+      if (!gsk_path_is_empty (path1) && !gsk_path_is_empty (path2))
+        g_string_append_c (str, ' ');
+      gsk_path_print (path2, str);
+
+      s = gsk_path_to_string (built);
+
+      g_assert_cmpstr (s, ==, str->str);
+      g_string_free (str, TRUE);
+      g_free (s);
+
+      gsk_path_unref (built);
+      gsk_path_unref (path2);
+      gsk_path_unref (path1);
+    }
+}
+
+static void
+test_parse (void)
+{
+  int i;
+
+  for (i = 0; i < 1000; i++)
+    {
+      GskPath *path1, *path2;
+      char *string1, *string2;
+
+      path1 = create_random_path (G_MAXUINT);
+      string1 = gsk_path_to_string (path1);
+      g_assert_nonnull (string1);
+
+      path2 = gsk_path_parse (string1);
+      g_assert_nonnull (path2);
+      string2 = gsk_path_to_string (path2);
+      g_assert_nonnull (string2);
+
+      assert_path_equal_with_epsilon (path1, path2, 1.f / 1024);
+
+      gsk_path_unref (path2);
+      gsk_path_unref (path1);
+      g_free (string2);
+      g_free (string1);
+    }
+}
+
+int
+main (int   argc,
+      char *argv[])
+{
+  gtk_test_init (&argc, &argv, NULL);
+
+  g_test_add_func ("/path/create", test_create);
+  g_test_add_func ("/path/parse", test_parse);
+
+  return g_test_run ();
+}

tools/gtk-path-tool-decompose.c

@@ -0,0 +1,142 @@
+/*  Copyright 2023 Red Hat, Inc.
+ *
+ * GTK+ 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 of the
+ * License, or (at your option) any later version.
+ *
+ * GLib 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 GTK+; see the file COPYING.  If not,
+ * see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Matthias Clasen
+ */
+
+#include "config.h"
+
+#include <gtk/gtk.h>
+#include "gtk-path-tool.h"
+
+#include <glib/gi18n-lib.h>
+
+static gboolean
+foreach_cb (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_QUAD:
+      gsk_path_builder_quad_to (builder, pts[1].x, pts[1].y, pts[2].x, pts[2].y);
+      break;
+
+    case GSK_PATH_CUBIC:
+      gsk_path_builder_cubic_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 ();
+    }
+
+  return TRUE;
+}
+
+void
+do_decompose (int *argc, const char ***argv)
+{
+  GError *error = NULL;
+  gboolean allow_quad = FALSE;
+  gboolean allow_curve = FALSE;
+  gboolean allow_conic = FALSE;
+  char **args = NULL;
+  GOptionContext *context;
+  GOptionEntry entries[] = {
+    { "allow-quad", 0, 0, G_OPTION_ARG_NONE, &allow_quad, N_("Allow quadratic Bézier curves"), NULL },
+    { "allow-cubic", 0, 0, G_OPTION_ARG_NONE, &allow_curve, N_("Allow cubic Bézier curves"), NULL },
+    { "allow-conic", 0, 0, G_OPTION_ARG_NONE, &allow_conic, N_("Allow rational quadratic Bézier curves"), NULL },
+    { G_OPTION_REMAINING, 0, 0, G_OPTION_ARG_FILENAME_ARRAY, &args, NULL, N_("PATH") },
+    { NULL, },
+  };
+  GskPathForeachFlags flags;
+  GskPath *path, *result;
+  GskPathBuilder *builder;
+
+  g_set_prgname ("gtk4-path-tool decompose");
+
+  context = g_option_context_new (NULL);
+  g_option_context_set_translation_domain (context, GETTEXT_PACKAGE);
+  g_option_context_add_main_entries (context, entries, NULL);
+  g_option_context_set_summary (context, _("Decompose a path."));
+
+  if (!g_option_context_parse (context, argc, (char ***)argv, &error))
+    {
+      g_printerr ("%s\n", error->message);
+      g_error_free (error);
+      exit (1);
+    }
+
+  g_option_context_free (context);
+
+  if (args == NULL)
+    {
+      g_printerr ("%s\n", _("No paths given."));
+      exit (1);
+    }
+
+  path = get_path (args[0]);
+
+  flags = 0;
+  if (allow_quad)
+    flags |= GSK_PATH_FOREACH_ALLOW_QUAD;
+  if (allow_curve)
+    flags |= GSK_PATH_FOREACH_ALLOW_CUBIC;
+  if (allow_conic)
+    flags |= GSK_PATH_FOREACH_ALLOW_CONIC;
+
+  builder = gsk_path_builder_new ();
+
+  gsk_path_foreach (path, flags, foreach_cb, builder);
+
+  result = gsk_path_builder_free_to_path (builder);
+
+  if (result)
+    {
+      char *str = gsk_path_to_string (result);
+      g_print ("%s\n", str);
+      g_free (str);
+    }
+  else
+    {
+      g_printerr ("%s\n", _("That didn't work out."));
+      exit (1);
+    }
+}

tools/gtk-path-tool-info.c

@@ -0,0 +1,80 @@
+/*  Copyright 2023 Red Hat, Inc.
+ *
+ * GTK+ 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 of the
+ * License, or (at your option) any later version.
+ *
+ * GLib 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 GTK+; see the file COPYING.  If not,
+ * see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Matthias Clasen
+ */
+
+#include "config.h"
+
+#include <gtk/gtk.h>
+#include "gtk-path-tool.h"
+
+#include <glib/gi18n-lib.h>
+
+void
+do_info (int *argc, const char ***argv)
+{
+  GError *error = NULL;
+  char **args = NULL;
+  GOptionContext *context;
+  GOptionEntry entries[] = {
+    { G_OPTION_REMAINING, 0, 0, G_OPTION_ARG_FILENAME_ARRAY, &args, NULL, N_("PATH") },
+    { NULL, },
+  };
+  GskPath *path;
+  GskPathMeasure *measure;
+  graphene_rect_t bounds;
+
+  g_set_prgname ("gtk4-path-tool info");
+
+  context = g_option_context_new (NULL);
+  g_option_context_set_translation_domain (context, GETTEXT_PACKAGE);
+  g_option_context_add_main_entries (context, entries, NULL);
+  g_option_context_set_summary (context, _("Print information about a path."));
+
+  if (!g_option_context_parse (context, argc, (char ***)argv, &error))
+    {
+      g_printerr ("%s\n", error->message);
+      g_error_free (error);
+      exit (1);
+    }
+
+  g_option_context_free (context);
+
+  if (args == NULL)
+    {
+      g_printerr ("%s\n", _("No paths given."));
+      exit (1);
+    }
+
+  path = get_path (args[0]);
+  measure = gsk_path_measure_new (path);
+
+  if (gsk_path_is_empty (path))
+    g_print ("%s\n", _("Path is empty."));
+  else
+    {
+      if (gsk_path_is_closed (path))
+        g_print ("%s\n", _("Path is closed"));
+
+      g_print ("%s %g\n", _("Path length"), gsk_path_measure_get_length (measure));
+
+      if (gsk_path_get_bounds (path, &bounds))
+        g_print ("%s: %g %g %g %g\n", _("Bounds"),
+                 bounds.origin.x, bounds.origin.y,
+                 bounds.size.width, bounds.size.height);
+    }
+}

tools/gtk-path-tool-render.c

@@ -0,0 +1,143 @@
+/*  Copyright 2023 Red Hat, Inc.
+ *
+ * GTK+ 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 of the
+ * License, or (at your option) any later version.
+ *
+ * GLib 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 GTK+; see the file COPYING.  If not,
+ * see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Matthias Clasen
+ */
+
+#include "config.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include <glib/gi18n-lib.h>
+#include <glib/gprintf.h>
+#include <glib/gstdio.h>
+#include <gtk/gtk.h>
+#include "gtk-path-tool.h"
+
+
+void
+do_render (int          *argc,
+           const char ***argv)
+{
+  GError *error = NULL;
+  const char *fill = "winding";
+  const char *fg_color = "black";
+  const char *bg_color = "white";
+  const char *output_file = NULL;
+  char **args = NULL;
+  GOptionContext *context;
+  const GOptionEntry entries[] = {
+    { "fill-rule", 0, 0, G_OPTION_ARG_STRING, &fill, N_("Fill rule (winding, even-odd)"), N_("VALUE") },
+    { "fg-color", 0, 0, G_OPTION_ARG_STRING, &fg_color, N_("Foreground color"), N_("COLOR") },
+    { "bg-color", 0, 0, G_OPTION_ARG_STRING, &bg_color, N_("Background color"), N_("COLOR") },
+    { "output", 0, 0, G_OPTION_ARG_FILENAME, &output_file, N_("The output file"), N_("FILE") },
+    { G_OPTION_REMAINING, 0, 0, G_OPTION_ARG_STRING_ARRAY, &args, NULL, N_("PATH") },
+    { NULL, }
+  };
+  GskPath *path;
+  GskFillRule fill_rule;
+  GdkRGBA fg, bg;
+  graphene_rect_t bounds;
+  GskRenderNode *fg_node, *nodes[2], *node;
+  GdkSurface *surface;
+  GskRenderer *renderer;
+  GdkTexture *texture;
+  const char *filename;
+
+  if (gdk_display_get_default () == NULL)
+    {
+      g_printerr ("%s\n", _("Could not initialize windowing system"));
+      exit (1);
+    }
+
+  g_set_prgname ("gtk4-path-tool render");
+  context = g_option_context_new (NULL);
+  g_option_context_set_translation_domain (context, GETTEXT_PACKAGE);
+  g_option_context_add_main_entries (context, entries, NULL);
+  g_option_context_set_summary (context, _("Render the path to a png image."));
+
+  if (!g_option_context_parse (context, argc, (char ***)argv, &error))
+    {
+      g_printerr ("%s\n", error->message);
+      g_error_free (error);
+      exit (1);
+    }
+
+  g_option_context_free (context);
+
+  if (args == NULL)
+    {
+      g_printerr ("%s\n", _("No path specified"));
+      exit (1);
+    }
+
+  if (g_strv_length (args) > 1)
+    {
+      g_printerr ("%s\n", _("Can only render a single path"));
+      exit (1);
+    }
+
+  path = get_path (args[0]);
+
+  fill_rule = get_enum_value (GSK_TYPE_FILL_RULE, _("fill rule"), fill);
+  get_color (&fg, fg_color);
+  get_color (&bg, bg_color);
+
+  gsk_path_get_bounds (path, &bounds);
+  graphene_rect_inset (&bounds, -10, -10);
+
+  nodes[0] = gsk_color_node_new (&bg, &bounds);
+  fg_node = gsk_color_node_new (&fg, &bounds);
+  nodes[1] = gsk_fill_node_new (fg_node, path, fill_rule);
+
+  node = gsk_container_node_new (nodes, 2);
+
+  gsk_render_node_unref (fg_node);
+  gsk_render_node_unref (nodes[0]);
+  gsk_render_node_unref (nodes[1]);
+
+  surface = gdk_surface_new_toplevel (gdk_display_get_default ());
+  renderer = gsk_renderer_new_for_surface (surface);
+
+  texture = gsk_renderer_render_texture (renderer, node, &bounds);
+
+  filename = output_file ? output_file : "path.png";
+  if (!gdk_texture_save_to_png (texture, filename))
+    {
+      char *msg = g_strdup_printf (_("Saving png to '%s' failed"), filename);
+      g_printerr ("%s\n", msg);
+      exit (1);
+    }
+
+  if (output_file == NULL)
+    {
+      char *msg = g_strdup_printf (_("Output written to '%s'."), filename);
+      g_print ("%s\n", msg);
+      g_free (msg);
+    }
+
+  g_object_unref (texture);
+  gsk_renderer_unrealize (renderer);
+  g_object_unref (renderer);
+  g_object_unref (surface);
+  gsk_render_node_unref (node);
+
+  gsk_path_unref (path);
+
+  g_strfreev (args);
+}

tools/gtk-path-tool-restrict.c

@@ -0,0 +1,93 @@
+/*  Copyright 2023 Red Hat, Inc.
+ *
+ * GTK+ 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 of the
+ * License, or (at your option) any later version.
+ *
+ * GLib 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 GTK+; see the file COPYING.  If not,
+ * see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Matthias Clasen
+ */
+
+#include "config.h"
+
+#include <gtk/gtk.h>
+#include "gtk-path-tool.h"
+
+#include <glib/gi18n-lib.h>
+
+void
+do_restrict (int *argc, const char ***argv)
+{
+  GError *error = NULL;
+  double start = G_MAXDOUBLE;
+  double end = G_MAXDOUBLE;
+  char **args = NULL;
+  GOptionContext *context;
+  GOptionEntry entries[] = {
+    { "start", 0, 0, G_OPTION_ARG_DOUBLE, &start, N_("Beginning of segment"), N_("LENGTH") },
+    { "end", 0, 0, G_OPTION_ARG_DOUBLE, &start, N_("End of segment"), N_("LENGTH") },
+    { G_OPTION_REMAINING, 0, 0, G_OPTION_ARG_FILENAME_ARRAY, &args, NULL, N_("PATH") },
+    { NULL, },
+  };
+  GskPath *path, *result;
+  GskPathMeasure *measure;
+  GskPathBuilder *builder;
+
+  g_set_prgname ("gtk4-path-tool restrict");
+
+  context = g_option_context_new (NULL);
+  g_option_context_set_translation_domain (context, GETTEXT_PACKAGE);
+  g_option_context_add_main_entries (context, entries, NULL);
+  g_option_context_set_summary (context, _("Restrict a path to a segment."));
+
+  if (!g_option_context_parse (context, argc, (char ***)argv, &error))
+    {
+      g_printerr ("%s\n", error->message);
+      g_error_free (error);
+      exit (1);
+    }
+
+  g_option_context_free (context);
+
+  if (args == NULL)
+    {
+      g_printerr ("%s\n", _("No paths given."));
+      exit (1);
+    }
+
+  path = get_path (args[0]);
+  measure = gsk_path_measure_new (path);
+
+  if (start == G_MAXDOUBLE)
+    start = 0;
+
+  if (end == G_MAXDOUBLE)
+    end = gsk_path_measure_get_length (measure);
+
+  builder = gsk_path_builder_new ();
+
+  gsk_path_builder_add_segment (builder, measure, start, end);
+
+  result = gsk_path_builder_free_to_path (builder);
+
+  if (result)
+    {
+      char *str = gsk_path_to_string (result);
+      g_print ("%s\n", str);
+      g_free (str);
+    }
+  else
+    {
+      g_printerr ("%s\n", _("That didn't work out."));
+      exit (1);
+    }
+}

tools/gtk-path-tool-show.c

@@ -0,0 +1,134 @@
+/*  Copyright 2023 Red Hat, Inc.
+ *
+ * GTK+ 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 of the
+ * License, or (at your option) any later version.
+ *
+ * GLib 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 GTK+; see the file COPYING.  If not,
+ * see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Matthias Clasen
+ */
+
+#include "config.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include <glib/gi18n-lib.h>
+#include <glib/gprintf.h>
+#include <glib/gstdio.h>
+#include <gtk/gtk.h>
+#include "gtk-path-tool.h"
+
+#include "path-view.h"
+
+static void
+show_path (GskPath       *path,
+           GskFillRule    fill_rule,
+           const GdkRGBA *fg_color,
+           const GdkRGBA *bg_color)
+{
+  GtkWidget *window, *sw, *child;
+
+  window = gtk_window_new ();
+  gtk_window_set_title (GTK_WINDOW (window), _("Path Preview"));
+
+//  gtk_window_set_default_size (GTK_WINDOW (window), 700, 500);
+
+  sw = gtk_scrolled_window_new ();
+  gtk_scrolled_window_set_propagate_natural_width (GTK_SCROLLED_WINDOW (sw), TRUE);
+  gtk_scrolled_window_set_propagate_natural_height (GTK_SCROLLED_WINDOW (sw), TRUE);
+  gtk_window_set_child (GTK_WINDOW (window), sw);
+
+  child = path_view_new (path);
+  g_object_set (child,
+                "fill-rule", fill_rule,
+                "fg-color", fg_color,
+                "bg-color", bg_color,
+                NULL);
+  gtk_widget_set_hexpand (child, TRUE);
+  gtk_widget_set_vexpand (child, TRUE);
+  gtk_scrolled_window_set_child (GTK_SCROLLED_WINDOW (sw), child);
+
+  gtk_window_present (GTK_WINDOW (window));
+
+  while (g_list_model_get_n_items (gtk_window_get_toplevels ()) > 0)
+    g_main_context_iteration (NULL, TRUE);
+}
+
+void
+do_show (int          *argc,
+         const char ***argv)
+{
+  GError *error = NULL;
+  const char *fill = "winding";
+  const char *fg_color = "black";
+  const char *bg_color = "white";
+  char **args = NULL;
+  GOptionContext *context;
+  const GOptionEntry entries[] = {
+    { "fill-rule", 0, 0, G_OPTION_ARG_STRING, &fill, N_("Fill rule (winding, even-odd)"), N_("VALUE") },
+    { "fg-color", 0, 0, G_OPTION_ARG_STRING, &fg_color, N_("Foreground color"), N_("COLOR") },
+    { "bg-color", 0, 0, G_OPTION_ARG_STRING, &bg_color, N_("Background color"), N_("COLOR") },
+    { G_OPTION_REMAINING, 0, 0, G_OPTION_ARG_STRING_ARRAY, &args, NULL, N_("PATH") },
+    { NULL, }
+  };
+  GskPath *path;
+  GskFillRule fill_rule;
+  GdkRGBA fg;
+  GdkRGBA bg;
+
+  if (gdk_display_get_default () == NULL)
+    {
+      g_printerr ("%s\n", _("Could not initialize windowing system"));
+      exit (1);
+    }
+
+  g_set_prgname ("gtk4-path-tool show");
+  context = g_option_context_new (NULL);
+  g_option_context_set_translation_domain (context, GETTEXT_PACKAGE);
+  g_option_context_add_main_entries (context, entries, NULL);
+  g_option_context_set_summary (context, _("Display the path."));
+
+  if (!g_option_context_parse (context, argc, (char ***)argv, &error))
+    {
+      g_printerr ("%s\n", error->message);
+      g_error_free (error);
+      exit (1);
+    }
+
+  g_option_context_free (context);
+
+  if (args == NULL)
+    {
+      g_printerr ("%s\n", _("No path specified"));
+      exit (1);
+    }
+
+  if (g_strv_length (args) > 1)
+    {
+      g_printerr ("%s\n", _("Can only show a single path"));
+      exit (1);
+    }
+
+  path = get_path (args[0]);
+
+  fill_rule = get_enum_value (GSK_TYPE_FILL_RULE, _("fill rule"), fill);
+  get_color (&fg, fg_color);
+  get_color (&bg, bg_color);
+
+  show_path (path, fill_rule, &fg, &bg);
+
+  gsk_path_unref (path);
+
+  g_strfreev (args);
+}

tools/gtk-path-tool-utils.c

@@ -0,0 +1,139 @@
+/*  Copyright 2023 Red Hat, Inc.
+ *
+ * GTK+ 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 of the
+ * License, or (at your option) any later version.
+ *
+ * GLib 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 GTK+; see the file COPYING.  If not,
+ * see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Matthias Clasen
+ */
+
+#include "config.h"
+
+#include <gtk/gtk.h>
+#include <gio/gio.h>
+#ifdef G_OS_UNIX
+#include <gio/gunixinputstream.h>
+#endif
+#include "gtk-path-tool.h"
+
+#include <glib/gi18n-lib.h>
+
+GskPath *
+get_path (const char *arg)
+{
+  char *buffer = NULL;
+  gsize len;
+  GError *error = NULL;
+  GskPath *path;
+
+  if (arg[0] == '.' || arg[0] == '/')
+    {
+      if (!g_file_get_contents (arg, &buffer, &len, &error))
+        {
+          g_printerr ("%s\n", error->message);
+          exit (1);
+        }
+    }
+#ifdef G_OS_UNIX
+  else if (strcmp (arg, "-") == 0)
+    {
+      GInputStream *in;
+      GOutputStream *out;
+
+      in = g_unix_input_stream_new (0, FALSE);
+      out = g_memory_output_stream_new (NULL, 0, g_realloc, g_free);
+
+      if (g_output_stream_splice (out, in, 0, NULL, &error) < 0)
+        {
+          g_printerr (_("Failed to read from standard input: %s\n"), error->message);
+          exit (1);
+        }
+
+      if (!g_output_stream_close (out, NULL, &error))
+        {
+          g_printerr (_("Error reading from standard input: %s\n"), error->message);
+          exit (1);
+        }
+
+      buffer = g_memory_output_stream_steal_data (G_MEMORY_OUTPUT_STREAM (out));
+
+      g_object_unref (out);
+      g_object_unref (in);
+    }
+#endif
+  else
+    buffer = g_strdup (arg);
+
+  g_strstrip (buffer);
+
+  path = gsk_path_parse (buffer);
+
+  if (path == NULL)
+    {
+      g_printerr (_("Failed to parse '%s' as path.\n"), arg);
+      exit (1);
+    }
+
+  g_free (buffer);
+
+  return path;
+}
+
+int
+get_enum_value (GType       type,
+                const char *type_nick,
+                const char *str)
+{
+  GEnumClass *class = g_type_class_ref (type);
+  GEnumValue *value;
+  int val;
+
+  value = g_enum_get_value_by_nick (class, str);
+  if (value)
+    val = value->value;
+  else
+    {
+      GString *s;
+
+      s = g_string_new ("");
+      g_string_append_printf (s, _("Failed to parse '%s' as %s."), str, type_nick);
+      g_string_append (s, "\n");
+      g_string_append (s, _("Possible values: "));
+
+      for (unsigned int i = 0; i < class->n_values; i++)
+        {
+          if (i > 0)
+            g_string_append (s, ", ");
+          g_string_append (s, class->values[i].value_nick);
+        }
+      g_printerr ("%s\n", s->str);
+      g_string_free (s, TRUE);
+      exit (1);
+    }
+
+  g_type_class_unref (class);
+
+  return val;
+}
+
+void
+get_color (GdkRGBA    *rgba,
+           const char *str)
+{
+  if (!gdk_rgba_parse (rgba, str))
+    {
+      char *msg = g_strdup_printf (_("Could not parse '%s' as color"), str);
+      g_printerr ("%s\n", msg);
+      exit (1);
+    }
+}

tools/gtk-path-tool.c

@@ -0,0 +1,142 @@
+/*  Copyright 2023 Red Hat, Inc.
+ *
+ * GTK+ 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 of the
+ * License, or (at your option) any later version.
+ *
+ * GLib 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 GTK+; see the file COPYING.  If not,
+ * see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Matthias Clasen
+ */
+
+#include "config.h"
+
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include <glib/gi18n-lib.h>
+#include <glib/gprintf.h>
+#include <glib/gstdio.h>
+#include <gtk/gtk.h>
+#include "gtk-path-tool.h"
+
+static void G_GNUC_NORETURN
+usage (void)
+{
+  g_print (_("Usage:\n"
+             "  gtk4-path-tool [COMMAND] [OPTION…] PATH\n"
+             "\n"
+             "Perform various tasks on paths.\n"
+             "\n"
+             "Commands:\n"
+             "  decompose    Decompose the path\n"
+             "  restrict     Restrict the path to a segment\n"
+             "  show         Display the path in a window\n"
+             "  render       Render the path as an image\n"
+             "  info         Print information about the path\n"
+             "\n"));
+  exit (1);
+}
+
+/* A simplified version of g_log_writer_default_would_drop(), to avoid
+ * bumping up the required version of GLib to 2.68
+ */
+static gboolean
+would_drop (GLogLevelFlags  level,
+            const char     *domain)
+{
+#if GLIB_CHECK_VERSION (2, 68, 0)
+  return g_log_writer_default_would_drop (level, domain);
+#else
+  return (level & (G_LOG_LEVEL_ERROR |
+                   G_LOG_LEVEL_CRITICAL |
+                   G_LOG_LEVEL_WARNING)) == 0;
+#endif
+}
+
+static GLogWriterOutput
+log_writer_func (GLogLevelFlags   level,
+                 const GLogField *fields,
+                 gsize            n_fields,
+                 gpointer         user_data)
+{
+  gsize i;
+  const char *domain = NULL;
+  const char *message = NULL;
+
+  for (i = 0; i < n_fields; i++)
+    {
+      if (g_strcmp0 (fields[i].key, "GLIB_DOMAIN") == 0)
+        domain = fields[i].value;
+      else if (g_strcmp0 (fields[i].key, "MESSAGE") == 0)
+        message = fields[i].value;
+    }
+
+  if (message != NULL && !would_drop (level, domain))
+    {
+      const char *prefix;
+      switch (level & G_LOG_LEVEL_MASK)
+        {
+        case G_LOG_LEVEL_ERROR:
+          prefix = "ERROR";
+          break;
+        case G_LOG_LEVEL_CRITICAL:
+          prefix = "CRITICAL";
+          break;
+        case G_LOG_LEVEL_WARNING:
+          prefix = "WARNING";
+          break;
+        default:
+          prefix = "INFO";
+          break;
+        }
+      g_printerr ("%s-%s: %s\n", domain, prefix, message);
+    }
+
+  return G_LOG_WRITER_HANDLED;
+}
+
+int
+main (int argc, const char *argv[])
+{
+  g_set_prgname ("gtk4-path-tool");
+
+  g_log_set_writer_func (log_writer_func, NULL, NULL);
+
+  gtk_init_check ();
+
+  gtk_test_register_all_types ();
+
+  if (argc < 2)
+    usage ();
+
+  if (strcmp (argv[1], "--help") == 0)
+    usage ();
+
+  argv++;
+  argc--;
+
+  if (strcmp (argv[0], "decompose") == 0)
+    do_decompose (&argc, &argv);
+  else if (strcmp (argv[0], "info") == 0)
+    do_info (&argc, &argv);
+  else if (strcmp (argv[0], "render") == 0)
+    do_render (&argc, &argv);
+  else if (strcmp (argv[0], "restrict") == 0)
+    do_restrict (&argc, &argv);
+  else if (strcmp (argv[0], "show") == 0)
+    do_show (&argc, &argv);
+  else
+    usage ();
+
+  return 0;
+}

tools/gtk-path-tool.h

@@ -0,0 +1,14 @@
+#pragma once
+
+void do_info      (int *argc, const char ***argv);
+void do_decompose (int *argc, const char ***argv);
+void do_restrict  (int *argc, const char ***argv);
+void do_render    (int *argc, const char ***argv);
+void do_show      (int *argc, const char ***argv);
+
+GskPath *get_path       (const char *arg);
+int      get_enum_value (GType       type,
+                         const char *type_nick,
+                         const char *str);
+void     get_color      (GdkRGBA    *rgba,
+                         const char *str);

tools/gtk-rendernode-tool-info.c

@@ -130,6 +130,14 @@ count_nodes (GskRenderNode *node,
       d = MAX (d, dd);
       break;
 
+    case GSK_FILL_NODE:
+      count_nodes (gsk_fill_node_get_child (node), counts, &d);
+      break;
+
+    case GSK_STROKE_NODE:
+      count_nodes (gsk_stroke_node_get_child (node), counts, &d);
+      break;
+
     case GSK_NOT_A_RENDER_NODE:
     default:
       g_assert_not_reached ();

tools/meson.build

@@ -23,6 +23,14 @@ if win32_enabled
 endif
 
 gtk_tools = [
+  ['gtk4-path-tool', ['gtk-path-tool.c',
+                      'gtk-path-tool-decompose.c',
+                      'gtk-path-tool-info.c',
+                      'gtk-path-tool-render.c',
+                      'gtk-path-tool-restrict.c',
+                      'gtk-path-tool-show.c',
+                      'gtk-path-tool-utils.c',
+                      'path-view.c'], [libgtk_dep]],
   ['gtk4-query-settings', ['gtk-query-settings.c'], [libgtk_dep]],
   ['gtk4-builder-tool', ['gtk-builder-tool.c',
                          'gtk-builder-tool-simplify.c',

tools/path-view.c

@@ -0,0 +1,221 @@
+/*  Copyright 2023 Red Hat, Inc.
+ *
+ * GTK+ 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 of the
+ * License, or (at your option) any later version.
+ *
+ * GLib 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 GTK+; see the file COPYING.  If not,
+ * see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Matthias Clasen
+ */
+
+#include "config.h"
+
+#include "path-view.h"
+
+struct _PathView
+{
+  GtkWidget parent_instance;
+
+  GskPath *path;
+  graphene_rect_t bounds;
+  GskFillRule fill_rule;
+  GdkRGBA fg;
+  GdkRGBA bg;
+  int padding;
+};
+
+enum {
+  PROP_PATH = 1,
+  PROP_FILL_RULE,
+  PROP_FG_COLOR,
+  PROP_BG_COLOR,
+  N_PROPERTIES
+};
+
+static GParamSpec *properties[N_PROPERTIES] = { NULL, };
+
+struct _PathViewClass
+{
+  GtkWidgetClass parent_class;
+};
+
+G_DEFINE_TYPE (PathView, path_view, GTK_TYPE_WIDGET)
+
+static void
+path_view_init (PathView *self)
+{
+  self->fill_rule = GSK_FILL_RULE_WINDING;
+  self->fg = (GdkRGBA) { 0, 0, 0, 1};
+  self->bg = (GdkRGBA) { 1, 1, 1, 1};
+  self->padding = 10;
+}
+
+static void
+path_view_dispose (GObject *object)
+{
+  PathView *self = PATH_VIEW (object);
+
+  g_clear_pointer (&self->path, gsk_path_unref);
+
+  G_OBJECT_CLASS (path_view_parent_class)->dispose (object);
+}
+
+static void
+path_view_get_property (GObject    *object,
+                        guint       prop_id,
+                        GValue     *value,
+                        GParamSpec *pspec)
+{
+  PathView *self = PATH_VIEW (object);
+
+  switch (prop_id)
+    {
+    case PROP_PATH:
+      g_value_set_boxed (value, self->path);
+      break;
+
+    case PROP_FILL_RULE:
+      g_value_set_enum (value, self->fill_rule);
+      break;
+
+    case PROP_FG_COLOR:
+      g_value_set_boxed (value, &self->fg);
+      break;
+
+    case PROP_BG_COLOR:
+      g_value_set_boxed (value, &self->bg);
+      break;
+
+     default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+static void
+path_view_set_property (GObject      *object,
+                        guint         prop_id,
+                        const GValue *value,
+                        GParamSpec   *pspec)
+{
+  PathView *self = PATH_VIEW (object);
+
+  switch (prop_id)
+    {
+    case PROP_PATH:
+      g_clear_pointer (&self->path, gsk_path_unref);
+      self->path = g_value_dup_boxed (value);
+      gsk_path_get_bounds (self->path, &self->bounds);
+      gtk_widget_queue_resize (GTK_WIDGET (self));
+      break;
+
+    case PROP_FILL_RULE:
+      self->fill_rule = g_value_get_enum (value);
+      gtk_widget_queue_draw (GTK_WIDGET (self));
+      break;
+
+    case PROP_FG_COLOR:
+      self->fg = *(GdkRGBA *) g_value_get_boxed (value);
+      gtk_widget_queue_draw (GTK_WIDGET (self));
+      break;
+
+    case PROP_BG_COLOR:
+      self->bg = *(GdkRGBA *) g_value_get_boxed (value);
+      gtk_widget_queue_draw (GTK_WIDGET (self));
+      break;
+
+     default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+      break;
+    }
+}
+
+
+static void
+path_view_measure (GtkWidget      *widget,
+                   GtkOrientation  orientation,
+                   int             for_size,
+                   int            *minimum,
+                   int            *natural,
+                   int            *minimum_baseline,
+                   int            *natural_baseline)
+{
+  PathView *self = PATH_VIEW (widget);
+
+  if (orientation == GTK_ORIENTATION_HORIZONTAL)
+    *minimum = *natural = (int) ceilf (self->bounds.size.width) + 2 * self->padding;
+  else
+    *minimum = *natural = (int) ceilf (self->bounds.size.height) + 2 * self->padding;
+}
+
+static void
+path_view_snapshot (GtkWidget   *widget,
+                    GtkSnapshot *snapshot)
+{
+  PathView *self = PATH_VIEW (widget);
+  graphene_rect_t bounds = self->bounds;
+
+  graphene_rect_inset (&bounds, - self->padding, - self->padding);
+
+  gtk_snapshot_save (snapshot);
+  gtk_snapshot_append_color (snapshot, &self->bg, &self->bounds);
+  gtk_snapshot_translate (snapshot, &GRAPHENE_POINT_INIT (self->padding, self->padding));
+  gtk_snapshot_push_fill (snapshot, self->path, self->fill_rule);
+  gtk_snapshot_append_color (snapshot, &self->fg, &self->bounds);
+  gtk_snapshot_pop (snapshot);
+  gtk_snapshot_restore (snapshot);
+}
+
+static void
+path_view_class_init (PathViewClass *class)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (class);
+  GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (class);
+
+  object_class->dispose = path_view_dispose;
+  object_class->get_property = path_view_get_property;
+  object_class->set_property = path_view_set_property;
+
+  widget_class->measure = path_view_measure;
+  widget_class->snapshot = path_view_snapshot;
+
+  properties[PROP_PATH]
+      = g_param_spec_boxed ("path", NULL, NULL,
+                            GSK_TYPE_PATH,
+                            G_PARAM_READWRITE|G_PARAM_EXPLICIT_NOTIFY);
+
+  properties[PROP_FILL_RULE]
+      = g_param_spec_enum ("fill-rule", NULL, NULL,
+                           GSK_TYPE_FILL_RULE,
+                           GSK_FILL_RULE_WINDING,
+                           G_PARAM_READWRITE|G_PARAM_EXPLICIT_NOTIFY);
+
+  properties[PROP_FG_COLOR]
+      = g_param_spec_boxed ("fg-color", NULL, NULL,
+                            GDK_TYPE_RGBA,
+                            G_PARAM_READWRITE|G_PARAM_EXPLICIT_NOTIFY);
+
+  properties[PROP_BG_COLOR]
+      = g_param_spec_boxed ("bg-color", NULL, NULL,
+                            GDK_TYPE_RGBA,
+                            G_PARAM_READWRITE|G_PARAM_EXPLICIT_NOTIFY);
+
+  g_object_class_install_properties (object_class, N_PROPERTIES, properties);
+}
+
+GtkWidget *
+path_view_new (GskPath *path)
+{
+  return g_object_new (PATH_TYPE_VIEW,
+                       "path", path,
+                       NULL);
+}

tools/path-view.h

@@ -0,0 +1,9 @@
+#pragma once
+
+#include <gtk/gtk.h>
+
+#define PATH_TYPE_VIEW (path_view_get_type ())
+
+G_DECLARE_FINAL_TYPE (PathView, path_view, PATH, VIEW, GtkWidget)
+
+GtkWidget * path_view_new (GskPath *path);