gstate: Update cached matrix state after device transform changes on the target

Commit 8d67186cb291cb877e52b987e2ac18c2a1175a57 caches whether the device
transform is identity on context creation. However, the api is quite lax
and allows the user to modify the device transform *after* he has
started to use the surface in a context, as apparently WebKit does.
Since this is not the only instance where we may need to invalidate
caches if the user modifies state, introduce a simple mechanism for
hooking into notifications of property changes.

Fixes test/clip-device-offset.

1 files changed, 50 insertions, 0 deletions

diff --git a/src/cairo-observer.c b/src/cairo-observer.c
new file mode 100644
index 000000000..7c7b69c91
--- /dev/null
+++ b/src/cairo-observer.c
@@ -0,0 +1,50 @@
+/* -*- Mode: c; tab-width: 8; c-basic-offset: 4; indent-tabs-mode: t; -*- */
+/* cairo - a vector graphics library with display and print output
+ *
+ * Copyright © 2010 Intel Corporation
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it either under the terms of the GNU Lesser General Public
+ * License version 2.1 as published by the Free Software Foundation
+ * (the "LGPL") or, at your option, under the terms of the Mozilla
+ * Public License Version 1.1 (the "MPL"). If you do not alter this
+ * notice, a recipient may use your version of this file under either
+ * the MPL or the LGPL.
+ *
+ * You should have received a copy of the LGPL along with this library
+ * in the file COPYING-LGPL-2.1; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA
+ * You should have received a copy of the MPL along with this library
+ * in the file COPYING-MPL-1.1
+ *
+ * The contents of this file are subject to the Mozilla Public License
+ * Version 1.1 (the "License"); you may not use this file except in
+ * compliance with the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
+ * OF ANY KIND, either express or implied. See the LGPL or the MPL for
+ * the specific language governing rights and limitations.
+ *
+ * The Original Code is the cairo graphics library.
+ *
+ * The Initial Developer of the Original Code is Intel Corporation
+ *
+ * Contributor(s):
+ *	Chris Wilson <chris@chris-wilson.co.uk>
+ */
+
+#include "cairoint.h"
+
+void
+_cairo_observers_notify (cairo_list_t *observers, void *arg)
+{
+    cairo_observer_t *obs, *next;
+
+    cairo_list_foreach_entry_safe (obs, next,
+				   cairo_observer_t,
+				   observers, link)
+    {
+	obs->callback (obs, arg);
+    }
+}