[gtk+/composite-templates] cssimage: Make cross-fades cross-fade properly

[Juan Pablo Ugarte <jpu src gnome org>]

commit c7cf17209a5f53674d53bf9734baabdddcfd8300
Author: Benjamin Otte <otte redhat com>
Date:   Fri Sep 14 17:24:33 2012 -0400

    cssimage: Make cross-fades cross-fade properly
    
    We need to use OPERATOR_SOURCE to properly fade out the start image
    when the end image contains transparency.

 gtk/gtkcssimagecrossfade.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkcssimagecrossfade.c b/gtk/gtkcssimagecrossfade.c
index f7f8a63..424703a 100644
--- a/gtk/gtkcssimagecrossfade.c
+++ b/gtk/gtkcssimagecrossfade.c
@@ -121,6 +121,7 @@ gtk_css_image_cross_fade_draw (GtkCssImage        *image,
                                                 cairo_get_target (cr),
                                                 width, height);
           cairo_set_source_surface (cr, surface, 0, 0);
+          cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
           cairo_paint_with_alpha (cr, cross_fade->progress);
           cairo_surface_destroy (surface);