Add a test for changing content

This is meant to produce lots of widget that all share the
same CSS and size, and frequently change content.

docs/reference/gtk/migrating-4to5.md

@@ -119,3 +119,19 @@ it no longer has a resize handle for the window.
 
 These are very specialized widgets that should better live with the application
 where they are used.
+
+## Widget size api changes
+
+The functions gtk_widget_get_allocated_width() and gtk_widget_get_allocated_height()
+are going away. In most cases, [method@Gtk.Widget.get_width] and [method@Gtk.Widget.get_height]
+are suitable replacements. Note that the semantics are slightly different though:
+the old functions return the size of the CSS border area, while the new functions return
+the size of the widgets content area. In places where this difference matters, you can
+use `gtk_widget_compute_bounds (widget, widget, &bounds)` instead.
+
+The function gtk_widget_get_allocation() is also going away. It does not have a direct
+replacement, but the previously mentioned alternatives can be used for it too.
+
+gtk_widget_translate_coordinates90 has been replaced by [method@Gtk.Widget.compute_point].
+
+The function gtk_widget_get_allocated_baseline() has been renamed to [method@Gtk.Widget.get_baseline].

tests/meson.build

@@ -1,5 +1,6 @@
 gtk_tests = [
   # testname, optional extra sources
+  ['testgridchanges'],
   ['input'],
   ['testpopup'],
   ['testupload'],

tests/testgridchanges.c

@@ -0,0 +1,189 @@
+#include <gtk/gtk.h>
+
+#define CONTENT_TYPE_WIDGET (content_widget_get_type ())
+G_DECLARE_FINAL_TYPE (ContentWidget, content_widget, CONTENT, WIDGET, GtkWidget)
+
+struct _ContentWidget
+{
+  GtkWidget parent_instance;
+
+  int pos;
+  GskRenderNode *content[10];
+
+  int width, height;
+};
+
+struct _ContentWidgetClass
+{
+  GtkWidgetClass parent_class;
+};
+
+G_DEFINE_TYPE (ContentWidget, content_widget, GTK_TYPE_WIDGET)
+
+static void
+content_widget_init (ContentWidget *self)
+{
+}
+
+static void
+content_widget_measure (GtkWidget      *widget,
+                         GtkOrientation  orientation,
+                         int             for_size,
+                         int            *minimum,
+                         int            *natural,
+                         int            *minimum_content,
+                         int            *natural_content)
+{
+  ContentWidget *self = CONTENT_WIDGET (widget);
+
+  *minimum_content = *natural_content = -1;
+  if (orientation == GTK_ORIENTATION_VERTICAL)
+    *minimum = *natural = self->height;
+   else
+    *minimum = *natural = self->width;
+}
+
+static void
+content_widget_snapshot (GtkWidget   *widget,
+                         GtkSnapshot *snapshot)
+{
+  ContentWidget *self = CONTENT_WIDGET (widget);
+
+  gtk_snapshot_append_node (snapshot, self->content[self->pos]);
+}
+
+static void
+content_widget_realize (GtkWidget *widget)
+{
+  ContentWidget *self = CONTENT_WIDGET (widget);
+  PangoLayout *layout;
+
+  GTK_WIDGET_CLASS (content_widget_parent_class)->realize (widget);
+
+  layout = gtk_widget_create_pango_layout (widget, "");
+
+  self->width = self->height = 0;
+
+  for (unsigned int i = 0; i < 10; i++)
+    {
+      char text[20];
+      GtkSnapshot *snapshot;
+      graphene_rect_t bounds;
+
+      g_snprintf (text, sizeof (text), "%u", i);
+      pango_layout_set_text (layout, text, -1);
+
+      snapshot = gtk_snapshot_new ();
+      gtk_snapshot_append_layout (snapshot, layout, &(GdkRGBA){ 0., 0., 0., 1. });
+      self->content[i] = gtk_snapshot_free_to_node (snapshot);
+
+      gsk_render_node_get_bounds (self->content[i], &bounds);
+      self->width = MAX (self->width, ceilf (bounds.origin.x + bounds.size.width));
+      self->height = MAX (self->height, ceilf (bounds.origin.y + bounds.size.height));
+    }
+
+  g_object_unref (layout);
+}
+
+static void
+content_widget_unrealize (GtkWidget *widget)
+{
+  ContentWidget *self = CONTENT_WIDGET (widget);
+
+  for (unsigned int i =0; i < 10; i++)
+    g_clear_pointer (&self->content[i], gsk_render_node_unref);
+
+  GTK_WIDGET_CLASS (content_widget_parent_class)->unrealize (widget);
+}
+
+static void
+content_widget_class_init (ContentWidgetClass *class)
+{
+  GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (class);
+
+  widget_class->snapshot = content_widget_snapshot;
+  widget_class->measure = content_widget_measure;
+  widget_class->realize = content_widget_realize;
+  widget_class->unrealize = content_widget_unrealize;
+
+  gtk_widget_class_set_css_name (widget_class, "content");
+}
+
+static GtkWidget *
+content_widget_new (void)
+{
+  return g_object_new (CONTENT_TYPE_WIDGET, NULL);
+}
+
+static void
+content_widget_set_pos (ContentWidget *self,
+                        int            pos)
+{
+  g_return_if_fail (CONTENT_IS_WIDGET (self));
+  g_return_if_fail (0 <= pos && pos < 10);
+
+  self->pos = pos;
+  gtk_widget_queue_draw (GTK_WIDGET (self));
+}
+
+static GtkWidget *cells[100][100];
+
+static gboolean
+change_content (GtkWidget     *widget,
+                GdkFrameClock *clock,
+                gpointer       user_data)
+{
+  for (unsigned int i = 0; i < 100; i++)
+    for (unsigned int j = 0; j < 100; j++)
+      content_widget_set_pos (CONTENT_WIDGET (cells[i][j]), g_random_int_range (0, 9));
+
+  return G_SOURCE_CONTINUE;
+}
+
+static const char css[] =
+"content {\n"
+"  background: pink;\n"
+"  border: 1px solid black;\n"
+"}";
+
+int
+main (int argc, char *argv[])
+{
+  GtkWidget *window, *sw, *grid;
+  GtkCssProvider *provider;
+
+  gtk_init ();
+
+  provider = gtk_css_provider_new ();
+  gtk_css_provider_load_from_data (provider, css, -1);
+  gtk_style_context_add_provider_for_display (gdk_display_get_default (),
+                                              GTK_STYLE_PROVIDER (provider),
+                                              1000);
+
+  window = gtk_window_new ();
+
+  sw = gtk_scrolled_window_new ();
+  gtk_window_set_child (GTK_WINDOW (window), sw);
+
+  grid = gtk_grid_new ();
+  gtk_scrolled_window_set_child (GTK_SCROLLED_WINDOW (sw), grid);
+
+  for (unsigned int i = 0; i < 100; i++)
+    for (unsigned int j = 0; j < 100; j++)
+      {
+        GtkWidget *child;
+
+        child = content_widget_new ();
+        gtk_grid_attach (GTK_GRID (grid), child, i, j, 1, 1);
+        cells[i][j] = child;
+      }
+
+  gtk_widget_add_tick_callback (window, change_content, NULL, NULL);
+
+  gtk_window_present (GTK_WINDOW (window));
+
+  while (g_list_model_get_n_items (gtk_window_get_toplevels ()) > 0)
+    g_main_context_iteration (NULL, FALSE);
+
+  return 0;
+}