[test] Add a simplified CLEAR test.

Just performs a very basic masked clear. This does not exhibit the bug I was
looking for, but is still useful for its simplicity.

test/Makefile.am

@@ -154,6 +154,10 @@ REFERENCE_IMAGES = \
 	caps-sub-paths.ref.png \
 	caps.ps.ref.png \
 	caps.ref.png \
+	clear.argb32.ref.png \
+	clear.rgb24.ref.png \
+	clear.svg12.argb32.xfail.png \
+	clear.svg12.rgb24.xfail.png \
 	clip-all.ref.png \
 	clip-empty.ref.png \
 	clip-fill-rule-pixel-aligned.ref.png \

test/Makefile.sources

@@ -12,6 +12,7 @@ test_sources = \
 	caps-joins-alpha.c				\
 	caps-joins-curve.c				\
 	caps-sub-paths.c				\
+	clear.c						\
 	clip-all.c					\
 	clip-empty.c					\
 	clip-fill-rule.c				\

test/clear.c

@@ -0,0 +1,86 @@
+/*
+ * Copyright © 2009 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"
+
+static cairo_test_status_t
+draw (cairo_t *cr, int width, int height)
+{
+    cairo_text_extents_t extents;
+
+    cairo_set_source_rgb (cr, 0, 0, 1);
+    cairo_paint (cr);
+
+    cairo_set_operator (cr, CAIRO_OPERATOR_CLEAR);
+
+    cairo_translate (cr, 2, 2);
+    cairo_save (cr);
+    cairo_rectangle (cr, 0, 0, 20, 20);
+    cairo_clip (cr);
+    cairo_rectangle (cr, 5, 5, 10, 10);
+    cairo_fill (cr);
+    cairo_restore (cr);
+
+    cairo_translate (cr, 20, 0);
+    cairo_save (cr);
+    cairo_rectangle (cr, 0, 0, 20, 20);
+    cairo_clip (cr);
+    cairo_arc (cr, 10, 10, 8, 0, 2*M_PI);
+    cairo_fill (cr);
+    cairo_restore (cr);
+
+    cairo_translate (cr, 0, 20);
+    cairo_save (cr);
+    cairo_rectangle (cr, 0, 0, 20, 20);
+    cairo_clip (cr);
+    cairo_text_extents (cr, "Cairo", &extents);
+    cairo_move_to (cr,
+	           10 - (extents.width/2. + extents.x_bearing),
+	           10 - (extents.height/2. + extents.y_bearing));
+    cairo_text_path (cr, "Cairo");
+    cairo_fill (cr);
+    cairo_restore (cr);
+
+    cairo_translate (cr, -20, 0);
+    cairo_save (cr);
+    cairo_rectangle (cr, 0, 0, 20, 20);
+    cairo_clip (cr);
+    cairo_move_to (cr, 10, 2);
+    cairo_line_to (cr, 18, 18);
+    cairo_line_to (cr, 2, 18);
+    cairo_close_path (cr);
+    cairo_fill (cr);
+    cairo_restore (cr);
+
+    return CAIRO_TEST_SUCCESS;
+}
+
+CAIRO_TEST (clear,
+	    "Test masked clears",
+	    "paint, clear", /* keywords */
+	    NULL, /* requirements */
+	    44, 44,
+	    NULL, draw)
+