[test/clip-all] Combine text and everything clipped out.

https://bugs.freedesktop.org/show_bug.cgi?id=13084 demonstrates a
regression where the clip is ignored by the xlib backend whilst
rendering text. Therefore we extend the current test cases to combine
a clip that represents everything clipped out with the rendering of
text. For completeness, we add a new test case that exactly mimics the
sequence of cairo operations that lead to the discovery of this bug -
namely the rendering of text with an empty clip path.

test/Makefile.am

@@ -8,6 +8,7 @@ caps-joins			\
 caps-joins-alpha		\
 caps-sub-paths			\
 clip-all			\
+clip-empty			\
 clip-fill-rule			\
 clip-fill-rule-pixel-aligned	\
 clip-nesting			\
@@ -221,6 +222,7 @@ REFERENCE_IMAGES = \
 	caps-joins-ref.png	\
 	caps-sub-paths-ref.png	\
 	clip-all-ref.png	\
+	clip-empty-ref.png	\
 	clip-fill-rule-pixel-aligned-ref.png	\
 	clip-fill-rule-pixel-aligned-rgb24-ref.png	\
 	clip-fill-rule-ps-argb32-ref.png	\

test/clip-all.c

@@ -62,6 +62,16 @@ draw (cairo_t *cr, int width, int height)
     cairo_set_source_rgb (cr, 1, 1, 0);
     cairo_fill (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");
+
+
     return CAIRO_TEST_SUCCESS;
 }
 

test/clip-empty.c

@@ -0,0 +1,72 @@
+/*
+ * 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_draw_function_t draw;
+
+cairo_test_t test = {
+    "clip-empty",
+    "Test clipping with an empty clip path",
+    SIZE, SIZE,
+    draw
+};
+
+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_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");
+
+    return CAIRO_TEST_SUCCESS;
+}
+
+int
+main (void)
+{
+    return cairo_test (&test);
+}