test: Add clip-empty-group

Exercise a bug reported by Jeff Muizelaar whereby cairo_push_group() was
broken by everything being clipped out.

4 files changed, 67 insertions, 0 deletions

diff --git a/test/Makefile.am b/test/Makefile.am
index 2b3205b7..5e2a3821 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -174,6 +174,7 @@ REFERENCE_IMAGES = \
 	clip-disjoint.ref.png \
 	clip-disjoint.xlib.ref.png \
 	clip-empty.ref.png \
+	clip-empty-group.ref.png \
 	clip-empty-save.ref.png \
 	clip-fill.ref.png \
 	clip-fill.ps.xfail.png \
diff --git a/test/Makefile.sources b/test/Makefile.sources
index 34143db9..1062e253 100644
--- a/test/Makefile.sources
+++ b/test/Makefile.sources
@@ -21,6 +21,7 @@ test_sources = \
 	clip-disjoint.c					\
 	clip-device-offset.c				\
 	clip-empty.c					\
+	clip-empty-group.c				\
 	clip-empty-save.c				\
 	clip-fill.c					\
 	clip-fill-no-op.c				\
diff --git a/test/clip-empty-group.c b/test/clip-empty-group.c
new file mode 100644
index 00000000..20e95c2b
--- /dev/null
+++ b/test/clip-empty-group.c
@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 2010 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person
+ * obtaining a copy of this software and associated documentation
+ * files (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy,
+ * modify, merge, publish, distribute, sublicense, and/or sell copies
+ * of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * Author: Chris Wilson <chris@chris-wilson.co.uk>
+ */
+
+#include "cairo-test.h"
+
+/* Test the handling of cairo_push_group() with everything clipped. */
+static cairo_test_status_t
+draw (cairo_t *cr, int width, int height)
+{
+    cairo_paint (cr); /* opaque background */
+
+    cairo_rectangle (cr,  20, 20, 0, 0);
+    cairo_clip (cr);
+
+    cairo_push_group (cr); /* => 0x0 group */
+    cairo_reset_clip (cr);
+
+    cairo_set_source_rgb (cr, 1, 0, 0);
+    cairo_paint (cr);
+
+    cairo_rectangle (cr, 0, 0, width, height);
+    cairo_set_source_rgba (cr, 0, 1, 0, .5);
+    cairo_fill (cr);
+
+    cairo_move_to (cr, 0, 20);
+    cairo_line_to (cr, width, 20);
+    cairo_set_source_rgb (cr, 0, 0, 1);
+    cairo_stroke (cr);
+
+    cairo_pop_group_to_source (cr);
+    cairo_reset_clip (cr);
+    cairo_paint (cr);
+
+    return CAIRO_TEST_SUCCESS;
+}
+
+CAIRO_TEST (clip_empty_group,
+	    "Test handling of groups with everything clipped",
+	    "clip group", /* keywords */
+	    NULL, /* requirements */
+	    40, 40,
+	    NULL, draw)
diff --git a/test/clip-empty-group.ref.png b/test/clip-empty-group.ref.png
new file mode 100644
index 00000000..a59ca472
--- /dev/null
+++ b/test/clip-empty-group.ref.png