test: Add clip-disjoint-quad

Exercises a bug in the polygon intersection code demonstrated by Søren
Sandmann.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

test/Makefile.sources

@@ -46,6 +46,7 @@ test_sources = \
 	clip-complex-shape.c				\
 	clip-disjoint.c					\
 	clip-disjoint-hatching.c			\
+	clip-disjoint-quad.c				\
 	clip-device-offset.c				\
 	clip-double-free.c				\
 	clip-draw-unbounded.c				\

test/clip-disjoint-quad.c

@@ -0,0 +1,83 @@
+/*
+ * Copyright © 2012 Red Hat, Inc.
+ * Copyright © 2012 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: Soren Sandmann <sandmann@redhat.com>
+ *         Chris Wilson <chris@chris-wilson.co.uk>
+ */
+
+#include "cairo-test.h"
+
+#define WIDTH 100
+#define HEIGHT 200
+
+static void
+draw_quad (cairo_t *cr,
+	   double x1, double y1,
+	   double x2, double y2,
+	   double x3, double y3,
+	   double x4, double y4)
+{
+    cairo_move_to (cr, x1, y1);
+    cairo_line_to (cr, x2, y2);
+    cairo_line_to (cr, x3, y3);
+    cairo_line_to (cr, x4, y4);
+    cairo_close_path (cr);
+
+    cairo_set_source_rgb (cr, 0, 0.6, 0);
+    cairo_fill (cr);
+}
+
+static cairo_test_status_t
+draw (cairo_t *cr, int width, int height)
+{
+    int position[5] = {0, HEIGHT/2-10, HEIGHT/2-5, HEIGHT/2, HEIGHT-10 };
+    int i;
+
+    cairo_set_source_rgb (cr, 0, 0, 0);
+    cairo_paint (cr);
+
+    for (i = 0; i < 5; i++) {
+	cairo_reset_clip (cr);
+	cairo_set_source_rgb (cr, 1, 1, 1);
+	cairo_rectangle (cr, 0, 0, WIDTH/2, HEIGHT/2);
+	cairo_rectangle (cr, WIDTH/2, position[i], WIDTH/2, 10);
+	cairo_fill_preserve (cr);
+	cairo_clip (cr);
+
+	cairo_set_source_rgb (cr, 1, 0, 1);
+	draw_quad (cr, 50, 50, 75, 75, 50, 150, 25, 75);
+	cairo_fill (cr);
+
+	cairo_translate(cr, WIDTH, 0);
+    }
+
+    return CAIRO_TEST_SUCCESS;
+}
+
+CAIRO_TEST (clip_disjoint_quad,
+	    "Tests a simple fill through two disjoint clips.",
+	    "clip, fill", /* keywords */
+	    NULL, /* requirements */
+	    5*WIDTH, HEIGHT,
+	    NULL, draw)