[gnome-panel/gtk3] Use xlib surface instead of image for composited pattern when panel background is an image

[Carlos Garcia Campos <carlosgc src gnome org>]

commit fe52d2c15fde6748b7f408e42eb4cad549dc5a19
Author: Carlos Garcia Campos <carlosgc gnome org>
Date:   Tue Jan 18 17:05:34 2011 +0100

    Use xlib surface instead of image for composited pattern when panel background is an image

 gnome-panel/panel-background.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/gnome-panel/panel-background.c b/gnome-panel/panel-background.c
index 30de4f1..37dbb0e 100644
--- a/gnome-panel/panel-background.c
+++ b/gnome-panel/panel-background.c
@@ -178,7 +178,9 @@ composite_image_onto_desktop (PanelBackground *background)
 	width  = gdk_pixbuf_get_width  (background->desktop);
 	height = gdk_pixbuf_get_height (background->desktop);
 
-	surface = cairo_image_surface_create (CAIRO_FORMAT_RGB24, width, height);
+        surface = gdk_window_create_similar_surface (background->window,
+                                                     CAIRO_CONTENT_COLOR_ALPHA,
+                                                     width, height);
         if (cairo_surface_status (surface)) {
                 cairo_surface_destroy (surface);
                 return NULL;