[mutter/wayland] MetaWindowActor: Use allocation changes signals for size changed signals

[Jasper St. Pierre <jstpierre src gnome org>]

commit 7c45d6594c3878fe1be463c3ab0358b7a3cbb32f
Author: Jonas Ådahl <jadahl gmail com>
Date:   Sun Oct 13 18:59:30 2013 +0200

    MetaWindowActor: Use allocation changes signals for size changed signals
    
    When a Wayland compositor, simply rely on the clutter actor allocation
    changed signal to sync geometry and emit window actor size changed
    signals.
    
    Attaching a wl_buffer to a MetaShapedTexture will signal allocation
    changed on the corresponding MetaSurfaceActor, which the MetaWindowActor
    is listening to.
    
    Signed-off-by: Jonas Ådahl <jadahl gmail com>
    
    https://bugzilla.gnome.org/show_bug.cgi?id=705502

 src/compositor/meta-window-actor.c |   26 ++++++++++++++++++++++++++
 1 files changed, 26 insertions(+), 0 deletions(-)
---
diff --git a/src/compositor/meta-window-actor.c b/src/compositor/meta-window-actor.c
index 019c1bc..a03f84f 100644
--- a/src/compositor/meta-window-actor.c
+++ b/src/compositor/meta-window-actor.c
@@ -53,6 +53,8 @@ struct _MetaWindowActorPrivate
 
   MetaSurfaceActor *surface;
 
+  guint             surface_allocation_changed_id;
+
   /* MetaShadowFactory only caches shadows that are actually in use;
    * to avoid unnecessary recomputation we do two things: 1) we store
    * both a focused and unfocused shadow for the window. If the window
@@ -299,6 +301,8 @@ meta_window_actor_init (MetaWindowActor *self)
   priv = self->priv = G_TYPE_INSTANCE_GET_PRIVATE (self,
                                                   META_TYPE_WINDOW_ACTOR,
                                                   MetaWindowActorPrivate);
+
+  priv->surface_allocation_changed_id = 0;
   priv->opacity = 0xff;
   priv->shadow_class = NULL;
 }
@@ -361,6 +365,17 @@ window_appears_focused_notify (MetaWindow *mw,
 }
 
 static void
+surface_allocation_changed_notify (ClutterActor           *actor,
+                                   const ClutterActorBox  *allocation,
+                                   ClutterAllocationFlags  flags,
+                                   MetaWindowActor        *self)
+{
+  meta_window_actor_sync_actor_geometry (self, FALSE);
+
+  g_signal_emit (self, signals[SIZE_CHANGED], 0);
+}
+
+static void
 meta_window_actor_constructed (GObject *object)
 {
   MetaWindowActor        *self     = META_WINDOW_ACTOR (object);
@@ -397,6 +412,12 @@ meta_window_actor_constructed (GObject *object)
       clutter_actor_add_child (CLUTTER_ACTOR (self), CLUTTER_ACTOR (priv->surface));
       clutter_actor_set_reactive (CLUTTER_ACTOR (self), TRUE);
 
+      priv->surface_allocation_changed_id =
+        g_signal_connect (CLUTTER_ACTOR (priv->surface),
+                          "allocation-changed",
+                          G_CALLBACK (surface_allocation_changed_notify),
+                          self);
+
       /*
        * Since we are holding a pointer to this actor independently of the
        * ClutterContainer internals, and provide a public API to access it,
@@ -482,6 +503,11 @@ meta_window_actor_dispose (GObject *object)
 
   g_clear_object (&priv->window);
 
+  if (priv->surface != NULL && priv->surface_allocation_changed_id != 0)
+    g_signal_handler_disconnect (priv->surface,
+                                 priv->surface_allocation_changed_id);
+  priv->surface_allocation_changed_id = 0;
+
   /*
    * Release the extra reference we took on the actor.
    */