test: Add clip-empty-save

Jeff Muizelaar found a bug in _cairo_clip_init_copy() which was not
correctly propagating the all-clipped status when an empty clip was
saved in the gstate. This test case exercises that bug.

test/Makefile.am

@@ -171,6 +171,7 @@ REFERENCE_IMAGES = \
 	clip-disjoint.ref.png \
 	clip-disjoint.xlib.ref.png \
 	clip-empty.ref.png \
+	clip-empty-save.ref.png \
 	clip-fill.ref.png \
 	clip-fill.ps.xfail.png \
 	clip-fill.xlib.ref.png \

test/Makefile.sources

@@ -18,6 +18,7 @@ test_sources = \
 	clip-disjoint.c					\
 	clip-device-offset.c				\
 	clip-empty.c					\
+	clip-empty-save.c				\
 	clip-fill.c					\
 	clip-fill-no-op.c				\
 	clip-fill-rule.c				\

test/clip-empty-save.c

@@ -0,0 +1,68 @@
+/*
+ * Copyright © 2007 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>
+ */
+
+#include "cairo-test.h"
+
+#define SIZE 10
+
+static cairo_test_status_t
+draw (cairo_t *cr, int width, int height)
+{
+    cairo_set_source_rgb (cr, 0, 0, 1);
+    cairo_paint (cr);
+
+    cairo_reset_clip (cr);
+    cairo_clip (cr);
+
+    cairo_save (cr);
+
+    cairo_translate (cr, .5, .5);
+
+    cairo_set_source_rgb (cr, 0, 1, 0);
+    cairo_rectangle (cr, 0, 0, SIZE, SIZE);
+    cairo_fill_preserve (cr);
+    cairo_set_source_rgb (cr, 1, 0, 0);
+    cairo_stroke (cr);
+
+    /* https://bugs.freedesktop.org/show_bug.cgi?id=13084 */
+    cairo_select_font_face (cr,
+	                    "Bitstream Vera Sans",
+			    CAIRO_FONT_SLANT_NORMAL,
+			    CAIRO_FONT_WEIGHT_NORMAL);
+
+    cairo_move_to (cr, 0., SIZE);
+    cairo_show_text (cr, "cairo");
+
+    cairo_restore (cr);
+
+    return CAIRO_TEST_SUCCESS;
+}
+
+CAIRO_TEST (clip_empty_save,
+	    "Test clipping with an empty clip path",
+	    "clip", /* keywords */
+	    NULL, /* requirements */
+	    SIZE, SIZE,
+	    NULL, draw)