test: Add an test case to exercise overlapping caps between dash segments

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

test/Makefile.refs

@@ -861,6 +861,7 @@ REFERENCE_IMAGES = \
 	over-between-source.svg12.rgb24.xfail.png \
 	over-between-source.xlib.ref.png \
 	over-between-source.xlib.rgb24.ref.png \
+	overlapping-dash-caps.ref.png \
 	overlapping-glyphs.argb32.ref.png \
 	overlapping-glyphs.pdf.argb32.xfail.png \
 	overlapping-glyphs.pdf.rgb24.xfail.png \

test/Makefile.sources

@@ -198,6 +198,7 @@ test_sources = \
 	over-below-source.c				\
 	over-between-source.c				\
 	overlapping-glyphs.c				\
+	overlapping-dash-caps.c				\
 	paint.c						\
 	paint-clip-fill.c				\
 	paint-repeat.c					\

test/overlapping-dash-caps.c

@@ -0,0 +1,58 @@
+/*
+ * Copyright © 2011 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: Chris Wilson <chris@chris-wilson.co.uk>
+ */
+
+#include "cairo-test.h"
+
+#define SIZE 100
+
+static cairo_test_status_t
+draw (cairo_t *cr, int width, int height)
+{
+    double dashes[] = {20, 10};
+
+    cairo_set_source_rgb (cr, 1, 1, 1);
+    cairo_paint (cr);
+
+    cairo_set_source_rgba (cr, 0, 0, 0, 0.5);
+
+    cairo_new_sub_path (cr);
+    cairo_arc (cr, SIZE/2, SIZE/2, SIZE/2-10, 0, 2*M_PI);
+
+    cairo_set_dash (cr, dashes, 2, 0);
+    cairo_set_line_cap (cr, CAIRO_LINE_CAP_ROUND);
+    cairo_set_line_width (cr, 15);
+
+    cairo_stroke (cr);
+
+    return CAIRO_TEST_SUCCESS;
+}
+
+CAIRO_TEST (overlapping_dash_caps,
+	    "Test intersections between neighbouring dash segments",
+	    "overlap, dash", /* keywords */
+	    NULL, /* requirements */
+	    SIZE, SIZE,
+	    NULL, draw)