[gtk+] stack: Clip animation drawing

[Benjamin Otte <otte src gnome org>]

commit 6bb8da5564d8403882035d037d4938a266e85c97
Author: Benjamin Otte <otte redhat com>
Date:   Thu Jan 21 01:44:47 2016 +0100

    stack: Clip animation drawing
    
    We use cairo_paint() when doing that and we don't want to overdraw the
    content area.

 gtk/gtkstack.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkstack.c b/gtk/gtkstack.c
index f765409..2effc1f 100644
--- a/gtk/gtkstack.c
+++ b/gtk/gtkstack.c
@@ -2148,6 +2148,12 @@ gtk_stack_render (GtkCssGadget *gadget,
               cairo_destroy (pattern_cr);
             }
 
+          cairo_rectangle (cr,
+                           0, 0,
+                           gtk_widget_get_allocated_width (widget),
+                           gtk_widget_get_allocated_height (widget));
+          cairo_clip (cr);
+
           switch (priv->active_transition_type)
             {
             case GTK_STACK_TRANSITION_TYPE_CROSSFADE: