[gnome-panel] panel: Fix themed background pattern

[Vincent Untz <vuntz src gnome org>]

commit 419f41024e58b3eba6bfc93881fce104aca09e63
Author: Peter Hurley <peter hurleysoftware com>
Date:   Fri Mar 2 15:45:01 2012 -0500

    panel: Fix themed background pattern
    
    When the panel background is set to None (ie, use system theme), and the
    theme defines a background-image css style for the PanelWidget (with
    -gtk-gradient, for example), a pattern is created (the default_pattern
    member) which is incorrectly drawn in certain areas. The incorrectly
    drawn areas of the panel are regions that are not occupied by child
    widgets. These regions are wiped by GDK (in
    gdk_window_clear_backing_region) to the background pattern previously
    set (in panel_background_prepare).
    
    Although it appears as though no pattern is drawn, in fact the gradient
    pattern *is* drawn, but not scaled properly so that appears as if only
    one gradient value is used to fill.
    
    This patch correctly scales the default_pattern (if present) to the
    width & height of the panel window.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=663397

 gnome-panel/panel-background.c |   17 +++++++++++++++--
 1 files changed, 15 insertions(+), 2 deletions(-)
---
diff --git a/gnome-panel/panel-background.c b/gnome-panel/panel-background.c
index afe879c..5de9883 100644
--- a/gnome-panel/panel-background.c
+++ b/gnome-panel/panel-background.c
@@ -56,10 +56,23 @@ panel_background_prepare (PanelBackground *background)
 
 	switch (effective_type) {
 	case PANEL_BACK_NONE:
-                if (background->default_pattern)
+                if (background->default_pattern) {
+			/* the theme background-image pattern must be scaled by
+			 * the width & height of the panel so that when the
+			 * backing region is cleared
+			 * (gdk_window_clear_backing_region), the correctly
+			 * scaled pattern is used */
+			cairo_matrix_t m;
+
+			cairo_matrix_init_translate (&m, 0, 0);
+			cairo_matrix_scale (&m,
+					    1.0 / background->region.width,
+					    1.0 / background->region.height);
+			cairo_pattern_set_matrix (background->default_pattern, &m);
+
                         gdk_window_set_background_pattern (background->window,
                                                           background->default_pattern);
-		else
+		} else
 			gdk_window_set_background_rgba (
 				background->window, &background->default_color);
 		break;