[test] Add test case for a leaky dashed rectangle.

Franz Schmid reported on the mailing list,
http://lists.cairographics.org/archives/cairo/2008-April/013912.html,
an issue with drawing a dashed rubber band in Scribus. The problem
appears when segments of the dashed rectangle are outside the image,
with the errant dash connecting the ends of the visible segments.

1 files changed, 92 insertions, 0 deletions

diff --git a/test/leaky-dashed-rectangle.c b/test/leaky-dashed-rectangle.c
new file mode 100644
index 000000000..0d9e2460b
--- /dev/null
+++ b/test/leaky-dashed-rectangle.c
@@ -0,0 +1,92 @@
+/*
+ * Copyright © 2008 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>
+ *         Franz Schmid <Franz.Schmid@altmuehlnet.de>
+ */
+
+/* Test case for bug reported by Franz Schmid <Franz.Schmid@altmuehlnet.de>
+ * http://lists.cairographics.org/archives/cairo/2008-April/013912.html
+ */
+
+#include "cairo-test.h"
+
+#define WIDTH 60
+#define HEIGHT 60
+
+static cairo_test_draw_function_t draw;
+
+cairo_test_t test = {
+    "leaky-dashed-rectangle",
+    "Exercises bug in which a dashed stroke leaks in from outside the surface",
+    WIDTH, HEIGHT,
+    draw
+};
+
+static cairo_test_status_t
+draw (cairo_t *cr, int width, int height)
+{
+    const double dash[2] = {4, 2};
+
+    cairo_set_source_rgb (cr, 1, 1, 1);
+    cairo_paint (cr);
+
+    cairo_set_source_rgb (cr, 0., 0., 0);
+
+    cairo_translate (cr, 0.5, .5);
+    cairo_set_line_width (cr, 1); /* This is vital to reproduce the bug. */
+
+    /* First check simple rectangles */
+    cairo_set_source_rgb (cr, 0., 0., 0);
+    cairo_rectangle (cr, -WIDTH/4, -HEIGHT/4, WIDTH, HEIGHT);
+    cairo_stroke (cr);
+    cairo_rectangle (cr, WIDTH+WIDTH/4, -HEIGHT/4, -WIDTH, HEIGHT);
+    cairo_stroke (cr);
+    cairo_rectangle (cr, -WIDTH/4, HEIGHT+HEIGHT/4, WIDTH, -HEIGHT);
+    cairo_stroke (cr);
+    cairo_rectangle (cr, WIDTH+WIDTH/4, HEIGHT+HEIGHT/4, -WIDTH, -HEIGHT);
+    cairo_stroke (cr);
+
+    cairo_set_dash (cr, dash, 2, 0);
+
+    /* And now dashed. */
+    cairo_set_source_rgb (cr, 1., 0., 0);
+    cairo_rectangle (cr, -WIDTH/4, -HEIGHT/4, WIDTH, HEIGHT);
+    cairo_stroke (cr);
+    cairo_set_source_rgb (cr, 0., 1., 0);
+    cairo_rectangle (cr, WIDTH+WIDTH/4, -HEIGHT/4, -WIDTH, HEIGHT);
+    cairo_stroke (cr);
+    cairo_set_source_rgb (cr, 0., 0., 1);
+    cairo_rectangle (cr, -WIDTH/4, HEIGHT+HEIGHT/4, WIDTH, -HEIGHT);
+    cairo_stroke (cr);
+    cairo_set_source_rgb (cr, 1., 1., 0);
+    cairo_rectangle (cr, WIDTH+WIDTH/4, HEIGHT+HEIGHT/4, -WIDTH, -HEIGHT);
+    cairo_stroke (cr);
+
+    return CAIRO_TEST_SUCCESS;
+}
+
+int
+main (void)
+{
+    return cairo_test (&test);
+}