[mutter] MetaBackgroundActor: Handle paint opacity

[Owen Taylor <otaylor src gnome org>]

commit 735c33bd9ffe4bae19e32638c0489e83beb90b85
Author: Owen W. Taylor <otaylor fishsoup net>
Date:   Sat Feb 12 17:41:07 2011 -0500

    MetaBackgroundActor: Handle paint opacity
    
    We were ignoring the opacity set on the background actor, causing problems,
    e.g., when fading out the workspace thumbnails in GNOME Shell.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=641979

 src/compositor/meta-background-actor.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/src/compositor/meta-background-actor.c b/src/compositor/meta-background-actor.c
index 77c8e31..7d980a1 100644
--- a/src/compositor/meta-background-actor.c
+++ b/src/compositor/meta-background-actor.c
@@ -190,10 +190,14 @@ static void
 meta_background_actor_paint (ClutterActor *actor)
 {
   MetaBackgroundActor *self = META_BACKGROUND_ACTOR (actor);
+  guchar opacity = clutter_actor_get_paint_opacity (actor);
   int width, height;
 
   meta_screen_get_size (self->screen, &width, &height);
 
+  cogl_material_set_color4ub (self->material,
+                              opacity, opacity, opacity, opacity);
+
   cogl_set_source (self->material);
 
   if (self->visible_region)