[test] Add a test for a reported regression by Michael Natterer.

mitch reported on irc that expose events in the gimp were suffering from
artifacts which he tracked down to a bug with clipping and source
surfaces. This is the cairo test case for that regression.

test/.gitignore

@@ -31,6 +31,7 @@ clip-push-group
 clip-twice
 clip-zero
 clipped-group
+clipped-surface
 close-path
 composite-integer-translate-over
 composite-integer-translate-over-repeat

test/Makefile.am

@@ -25,6 +25,7 @@ clip-push-group$(EXEEXT)				\
 clip-twice$(EXEEXT)					\
 clip-zero$(EXEEXT)					\
 clipped-group$(EXEEXT)					\
+clipped-surface$(EXEEXT)				\
 close-path$(EXEEXT)					\
 composite-integer-translate-source$(EXEEXT)		\
 composite-integer-translate-over$(EXEEXT)		\
@@ -346,6 +347,7 @@ REFERENCE_IMAGES = \
 	clipped-group-ref.png	\
 	clipped-group-ps2-ref.png	\
 	clipped-group-ps3-ref.png	\
+	clipped-surface-ref.png	\
 	close-path-ref.png	\
 	close-path-ps2-ref.png	\
 	close-path-ps3-ref.png	\

test/clipped-surface.c

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2008 Chris Wilson
+ *
+ * Permission to use, copy, modify, distribute, and sell this software
+ * and its documentation for any purpose is hereby granted without
+ * fee, provided that the above copyright notice appear in all copies
+ * and that both that copyright notice and this permission notice
+ * appear in supporting documentation, and that the name of
+ * Chris Wilson not be used in advertising or publicity pertaining to
+ * distribution of the software without specific, written prior
+ * permission. Chris Wilson makes no representations about the
+ * suitability of this software for any purpose.  It is provided "as
+ * is" without express or implied warranty.
+ *
+ * CHRIS WILSON DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
+ * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS, IN NO EVENT SHALL CHRIS WILSON BE LIABLE FOR ANY SPECIAL,
+ * INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER
+ * RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
+ * IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * Author: Chris Wilson <chris@chris-wilson.co.uk>
+ */
+
+/*
+ * Michael Natterer (mitch) reported a bad regression with post-1.8 trunk
+ * with artifacts drawn whilst repainting exposed areas.
+ */
+
+#include "cairo-test.h"
+
+static const char png_filename[] = "romedalen.png";
+static cairo_test_draw_function_t draw;
+
+static const cairo_test_t test = {
+    "clipped-surface",
+    "Tests application of a clip to a source surface",
+    40, 40,
+    draw
+};
+
+static cairo_test_status_t
+draw (cairo_t *cr, int width, int height)
+{
+    const cairo_test_context_t *ctx = cairo_test_get_context (cr);
+    cairo_surface_t *image;
+
+    image = cairo_test_create_surface_from_png (ctx, png_filename);
+
+    cairo_set_source_rgb (cr, 1, 0, 0);
+    cairo_paint (cr);
+
+    cairo_rectangle (cr, 20, 20, 10, 10);
+    cairo_clip (cr);
+
+    cairo_set_source_surface (cr, image, 10, 10);
+    cairo_surface_destroy (image);
+
+    cairo_rectangle (cr, 10, 10, 20, 20);
+    cairo_fill (cr);
+
+    return CAIRO_TEST_SUCCESS;
+}
+
+int
+main (void)
+{
+    return cairo_test (&test);
+}