[clutter-gtk] actor: propagate scale factor from embedder to embedded

[Lionel Landwerlin <llandwerlin src gnome org>]

commit 3609c70c3518a83d362e81e37e21c335bff49c1b
Author: Lionel Landwerlin <llandwerlin gmail com>
Date:   Tue Dec 1 22:38:01 2015 +0000

    actor: propagate scale factor from embedder to embedded
    
    We need to set the scale factor correctly on the embedded Gtk+ widgets to
    avoid blurry widgets on hidpi displays.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=758937

 clutter-gtk/gtk-clutter-actor.c     |   15 +++++++++++++++
 clutter-gtk/gtk-clutter-offscreen.c |    2 ++
 2 files changed, 17 insertions(+), 0 deletions(-)
---
diff --git a/clutter-gtk/gtk-clutter-actor.c b/clutter-gtk/gtk-clutter-actor.c
index 9582154..6b78628 100644
--- a/clutter-gtk/gtk-clutter-actor.c
+++ b/clutter-gtk/gtk-clutter-actor.c
@@ -199,6 +199,7 @@ gtk_clutter_actor_realize (ClutterActor *actor)
   else
 #endif
     {
+      GdkWindow *window = gtk_widget_get_window (priv->widget);
       int width = gtk_widget_get_allocated_width (priv->widget);
       int height = gtk_widget_get_allocated_height (priv->widget);
 
@@ -206,6 +207,8 @@ gtk_clutter_actor_realize (ClutterActor *actor)
 
       clutter_actor_set_size (priv->texture, width, height);
 
+      clutter_canvas_set_scale_factor (CLUTTER_CANVAS (priv->canvas),
+                                       gdk_window_get_scale_factor (window));
       /* clutter_canvas_set_size() will invalidate its contents only
        * if the size differs, but we want to invalidate the contents
        * in any case; we cannot call clutter_content_invalidate()
@@ -310,6 +313,7 @@ gtk_clutter_actor_allocate (ClutterActor           *actor,
   GtkAllocation child_allocation;
   GdkWindow *window;
   ClutterActorBox child_box;
+  gint dummy;
 
   _gtk_clutter_offscreen_set_in_allocation (GTK_CLUTTER_OFFSCREEN (priv->widget), TRUE);
 
@@ -317,6 +321,15 @@ gtk_clutter_actor_allocate (ClutterActor           *actor,
   child_allocation.y = 0;
   child_allocation.width = clutter_actor_box_get_width (box);
   child_allocation.height = clutter_actor_box_get_height (box);
+
+  /* Silence the following GTK+ warning:
+   *
+   * Gtk-WARNING **: Allocating size to Offscreen Container
+   * without calling gtk_widget_get_preferred_width/height(). How does the
+   * code know the size to allocate?
+   */
+  gtk_widget_get_preferred_width (priv->widget, &dummy, NULL);
+
   gtk_widget_size_allocate (priv->widget, &child_allocation);
 
   if (CLUTTER_ACTOR_IS_REALIZED (actor))
@@ -352,6 +365,8 @@ gtk_clutter_actor_allocate (ClutterActor           *actor,
         {
           DEBUG (G_STRLOC ": Using image surface.\n");
 
+          clutter_canvas_set_scale_factor (CLUTTER_CANVAS (priv->canvas),
+                                           gdk_window_get_scale_factor (window));
           clutter_canvas_set_size (CLUTTER_CANVAS (priv->canvas),
                                    gtk_widget_get_allocated_width (priv->widget),
                                    gtk_widget_get_allocated_height (priv->widget));
diff --git a/clutter-gtk/gtk-clutter-offscreen.c b/clutter-gtk/gtk-clutter-offscreen.c
index c54010d..7243420 100644
--- a/clutter-gtk/gtk-clutter-offscreen.c
+++ b/clutter-gtk/gtk-clutter-offscreen.c
@@ -144,6 +144,8 @@ gtk_clutter_offscreen_realize (GtkWidget *widget)
   gtk_widget_set_window (widget, window);
   gdk_window_set_user_data (window, widget);
 
+  gdk_offscreen_window_set_embedder (gtk_widget_get_window (parent),
+                                     window);
   g_signal_connect (window, "to-embedder",
                    G_CALLBACK (offscreen_window_to_parent),
                     widget);