[gtk+/multitouch-for-3.4: 76/89] scrolledwindow: Use the child widget's window bg color for the overshoot area

[Carlos Garnacho <carlosg src gnome org>]

commit 49daf22cf1ff94bec4a4c299caf1037240946794
Author: Carlos Garnacho <carlosg gnome org>
Date:   Thu Jan 12 02:53:47 2012 +0100

    scrolledwindow: Use the child widget's window bg color for the overshoot area
    
    This makes the overshoot area seamless, if the child plays along.

 gtk/gtkscrolledwindow.c |   24 +++++++++++++++++++++---
 1 files changed, 21 insertions(+), 3 deletions(-)
---
diff --git a/gtk/gtkscrolledwindow.c b/gtk/gtkscrolledwindow.c
index d0bde13..af5923c 100644
--- a/gtk/gtkscrolledwindow.c
+++ b/gtk/gtkscrolledwindow.c
@@ -1406,14 +1406,32 @@ gtk_scrolled_window_draw (GtkWidget *widget,
   GtkScrolledWindow *scrolled_window = GTK_SCROLLED_WINDOW (widget);
   GtkScrolledWindowPrivate *priv = scrolled_window->priv;
   GtkAllocation relative_allocation;
+  cairo_pattern_t *pattern = NULL;
   GtkStyleContext *context;
+  GtkWidget *child;
 
   context = gtk_widget_get_style_context (widget);
   gtk_scrolled_window_relative_allocation (widget, &relative_allocation);
 
-  gtk_render_background (context, cr,
-                         relative_allocation.x, relative_allocation.y,
-                         relative_allocation.width, relative_allocation.height);
+  /* Use child's background if possible */
+  child = gtk_bin_get_child (GTK_BIN (widget));
+
+  if (child && gtk_widget_get_has_window (child))
+    pattern = gdk_window_get_background_pattern (gtk_widget_get_window (child));
+
+  if (pattern &&
+      cairo_pattern_get_type (pattern) == CAIRO_PATTERN_TYPE_SOLID)
+    {
+      cairo_set_source (cr, pattern);
+
+      cairo_rectangle (cr, relative_allocation.x, relative_allocation.y,
+                       relative_allocation.width, relative_allocation.height);
+      cairo_fill (cr);
+    }
+  else
+    gtk_render_background (context, cr,
+                           relative_allocation.x, relative_allocation.y,
+                           relative_allocation.width, relative_allocation.height);
 
   if (priv->shadow_type != GTK_SHADOW_NONE)
     {