[gtk+] viewport: Clip contents properly when called via gtk_widget_draw()

[Benjamin Otte <otte src gnome org>]

commit 04c630d0fd713a683e6a1eb8f3bd7fb9c70a2b1d
Author: Benjamin Otte <otte redhat com>
Date:   Tue Oct 5 23:22:25 2010 +0200

    viewport: Clip contents properly when called via gtk_widget_draw()

 gtk/gtkviewport.c |   15 +++++++++++++++
 1 files changed, 15 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkviewport.c b/gtk/gtkviewport.c
index 7f24b54..5988682 100644
--- a/gtk/gtkviewport.c
+++ b/gtk/gtkviewport.c
@@ -784,6 +784,21 @@ gtk_viewport_draw (GtkWidget *widget,
                         gdk_window_get_height (gtk_widget_get_window (widget)));
     }
   
+  if (gtk_cairo_should_draw_window (cr, priv->view_window))
+    {
+      /* This is a cute hack to ensure the contents of bin_window are
+       * restricted to where they are visible. We only need to do this
+       * clipping when called via gtk_widget_draw() and not in expose
+       * events. And when that happens every window (including this one)
+       * should be drawn.
+       */
+      gdk_window_get_position (priv->view_window, &x, &y);
+      cairo_rectangle (cr, x, y, 
+                       gdk_window_get_width (priv->view_window),
+                       gdk_window_get_height (priv->view_window));
+      cairo_clip (cr);
+    }
+
   if (gtk_cairo_should_draw_window (cr, priv->bin_window))
     {
       gdk_window_get_position (priv->bin_window, &x, &y);