[test] Add clip-disjoint

Soeren found another bug (thanks Soeren!) in the clipping code - as
reproduced by this test case.

test/Makefile.am

@@ -161,6 +161,8 @@ REFERENCE_IMAGES = \
 	clear.svg12.argb32.xfail.png \
 	clear.svg12.rgb24.xfail.png \
 	clip-all.ref.png \
+	clip-disjoint.ref.png \
+	clip-disjoint.xlib.ref.png \
 	clip-empty.ref.png \
 	clip-fill.ref.png \
 	clip-fill.ps.xfail.png \

test/Makefile.sources

@@ -14,6 +14,7 @@ test_sources = \
 	caps-sub-paths.c				\
 	clear.c						\
 	clip-all.c					\
+	clip-disjoint.c					\
 	clip-empty.c					\
 	clip-fill.c					\
 	clip-fill-rule.c				\

test/clip-disjoint.c

@@ -0,0 +1,90 @@
+/*
+ * Copyright © 2008 Red Hat, Inc.
+ *
+ * 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
+ * Red Hat, Inc. not be used in advertising or publicity pertaining to
+ * distribution of the software without specific, written prior
+ * permission. Red Hat, Inc. makes no representations about the
+ * suitability of this software for any purpose.  It is provided "as
+ * is" without express or implied warranty.
+ *
+ * RED HAT, INC. DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
+ * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+ * FITNESS, IN NO EVENT SHALL RED HAT, INC. 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: Soren Sandmann <sandmann@redhat.com>
+ */
+
+#include "cairo-test.h"
+
+#define WIDTH 300
+#define HEIGHT 300
+
+typedef struct {
+    double x, y;
+} point_t;
+
+static void
+paint_curve (cairo_t *cr)
+{
+    const point_t points[] = {
+	{ 100, 320 }, { 110, -80 },
+	{ 180, 60 }, { 300, 170 },
+	{ 300, -40 }
+    };
+    unsigned i;
+
+    cairo_set_line_width (cr, 2);
+    cairo_move_to (cr, points[0].x, points[0].y);
+
+    for (i = 1; i < sizeof (points) / sizeof (points[0]) - 2; i += 3) {
+	cairo_curve_to (cr,
+			points[i].x, points[i].y,
+			points[i + 1].x, points[i + 1].y,
+			points[i + 2].x, points[i + 2].y);
+    }
+    cairo_set_line_width (cr, 5);
+    cairo_stroke (cr);
+}
+
+static cairo_test_status_t
+draw (cairo_t *cr, int width, int height)
+{
+    /* Fill window with light blue */
+    cairo_set_source_rgba (cr, 0.8, 0.8, 1.9, 1.0);
+    cairo_paint (cr);
+
+    /* Paint curve in green */
+    cairo_set_source_rgba (cr, 0.6, 0.8, 0.6, 1.0);
+    paint_curve (cr);
+
+    /* Make clip region */
+    cairo_rectangle (cr, 228, 131, 50, 13);
+    cairo_rectangle (cr, 20, 99, 200, 75);
+    cairo_clip_preserve (cr);
+
+    /* Fill clip region with red */
+    cairo_set_source_rgba (cr, 1.0, 0.5, 0.5, 0.8);
+    cairo_fill (cr);
+
+    /* Paint curve again, this time in blue */
+    cairo_set_source_rgba (cr, 0, 0, 1.0, 1.0);
+    paint_curve (cr);
+
+    return CAIRO_TEST_SUCCESS;
+}
+
+CAIRO_TEST (clip_disjoint,
+	    "Tests stroking through two disjoint clips.",
+	    "clip, stroke", /* keywords */
+	    NULL, /* requirements */
+	    WIDTH, HEIGHT,
+	    NULL, draw)