[gtk-vnc-devel] PATCH: Clear areas outside of framebuffer region

["Daniel P. Berrange" <berrange redhat com>]

If the GTK-VNC widget gets resized to be larger than the region taken up
by the remote framebuffer, the excess space just gets filled with random
garbage.  This is seen in Vinagre if you hit "Full Screen"

The attached patch calls gdk_draw_rectangle to fill the excess space with
a solid colour (black). It uses a clip mask to ensure we don't clear the
space where the actual framebuffer is & thus avoids flickr that would entail.

Dan.
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diff -r 453f9ca2a737 src/vncdisplay.c
--- a/src/vncdisplay.c	Wed Aug 22 10:40:33 2007 -0400
+++ b/src/vncdisplay.c	Wed Aug 22 12:48:09 2007 -0400
@@ -103,6 +103,8 @@ static gboolean expose_event(GtkWidget *
 	VncDisplay *obj = VNC_DISPLAY(widget);
 	VncDisplayPrivate *priv = obj->priv;
 	int x, y, w, h;
+	GdkRectangle drawn;
+	GdkRegion *clear, *copy;
 
 	if (priv->shm_image == NULL)
 		return TRUE;
@@ -114,9 +116,27 @@ static gboolean expose_event(GtkWidget *
 	w -= x;
 	h -= y;
 
+	drawn.x = x;
+	drawn.y = y;
+	drawn.width = w;
+	drawn.height = h;
+
+	clear = gdk_region_rectangle(&expose->area);
+	copy = gdk_region_rectangle(&drawn);
+	gdk_region_subtract(clear, copy);
+
+	gdk_gc_set_clip_region(priv->gc, copy);
 	vnc_shm_image_draw(priv->shm_image, widget->window,
-			   priv->gc, 
+			   priv->gc,
 			   x, y, x, y, w, h);
+
+	gdk_gc_set_clip_region(priv->gc, clear);
+	gdk_draw_rectangle(widget->window, priv->gc, TRUE, expose->area.x, expose->area.y,
+			   expose->area.width, expose->area.height);
+
+	gdk_region_destroy(clear);
+	gdk_region_destroy(copy);
+
 	return TRUE;
 }