test: Add line-width-large-overlap

Exercise the case of stroking a box with a pen wider than the box
itself, a variation on line-width-overlap suggested by Paulo Zanoni.

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

test/Makefile.sources

@@ -169,6 +169,7 @@ test_sources = \
 	leaky-dashed-stroke.c				\
 	leaky-polygon.c					\
 	line-width.c					\
+	line-width-large-overlap.c			\
 	line-width-overlap.c				\
 	line-width-scale.c				\
 	line-width-tolerance.c				\

test/line-width-large-overlap.c

@@ -0,0 +1,149 @@
+/* -*- Mode: c; c-basic-offset: 4; indent-tabs-mode: t; tab-width: 8; -*- */
+/*
+ * Copyright 2011 Red Hat Inc.
+ *
+ * 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: Benjamin Otte <otte@redhat.com>
+ */
+
+/*
+ * Test case taken from the WebKit test suite, failure originally reported
+ * by Zan Dobersek <zandobersek@gmail.com>. WebKit test is
+ * LayoutTests/canvas/philip/tests/2d.path.rect.selfintersect.html
+ */
+
+#include "cairo-test.h"
+
+#include <math.h>
+
+#define LINE_WIDTH 120
+#define SIZE 100
+#define RECT_SIZE 10
+
+static cairo_test_status_t
+draw (cairo_t *cr, int width, int height)
+{
+    /* fill with green so RGB and RGBA tests can share the ref image */
+    cairo_set_source_rgb (cr, 0, 1, 0);
+    cairo_paint (cr);
+
+    /* red to see eventual bugs immediately */
+    cairo_set_source_rgb (cr, 1, 0, 0);
+
+    /* big line width */
+    cairo_set_line_width (cr, LINE_WIDTH);
+
+    /* rectangle that is smaller than the line width in center of image */
+    cairo_rectangle (cr,
+                     (SIZE - RECT_SIZE) / 2,
+                     (SIZE - RECT_SIZE) / 2,
+                     RECT_SIZE,
+                     RECT_SIZE);
+
+    cairo_stroke (cr);
+
+    return CAIRO_TEST_SUCCESS;
+}
+
+/* and again slightly offset to trigger another path */
+static cairo_test_status_t
+draw_offset (cairo_t *cr, int width, int height)
+{
+    cairo_translate (cr, .5, .5);
+    return draw (cr, width, height);
+}
+
+static cairo_test_status_t
+draw_rotated (cairo_t *cr, int width, int height)
+{
+    cairo_translate (cr, SIZE/2, SIZE/2);
+    cairo_rotate (cr, M_PI/4);
+    cairo_translate (cr, -SIZE/2, -SIZE/2);
+
+    return draw (cr, width, height);
+}
+
+static cairo_test_status_t
+draw_flipped (cairo_t *cr, int width, int height)
+{
+    cairo_translate (cr, SIZE/2, SIZE/2);
+    cairo_scale (cr, -1, 1);
+    cairo_translate (cr, -SIZE/2, -SIZE/2);
+
+    return draw (cr, width, height);
+}
+
+static cairo_test_status_t
+draw_flopped (cairo_t *cr, int width, int height)
+{
+    cairo_translate (cr, SIZE/2, SIZE/2);
+    cairo_scale (cr, 1, -1);
+    cairo_translate (cr, -SIZE/2, -SIZE/2);
+
+    return draw (cr, width, height);
+}
+
+static cairo_test_status_t
+draw_dashed (cairo_t *cr, int width, int height)
+{
+    const double dashes[] = { 4 };
+    cairo_set_dash (cr, dashes, 1, 0);
+    cairo_set_line_cap (cr, CAIRO_LINE_CAP_BUTT);
+    return draw (cr, width, height);
+}
+
+CAIRO_TEST (line_width_large_overlap,
+	    "Test overlapping lines due to large line width",
+	    "stroke", /* keywords */
+	    NULL, /* requirements */
+	    SIZE, SIZE,
+	    NULL, draw)
+CAIRO_TEST (line_width_large_overlap_offset,
+	    "Test overlapping lines due to large line width",
+	    "stroke", /* keywords */
+	    NULL, /* requirements */
+	    SIZE, SIZE,
+	    NULL, draw_offset)
+CAIRO_TEST (line_width_large_overlap_rotated,
+	    "Test overlapping lines due to large line width",
+	    "stroke", /* keywords */
+	    NULL, /* requirements */
+	    SIZE, SIZE,
+	    NULL, draw_rotated)
+CAIRO_TEST (line_width_large_overlap_flipped,
+	    "Test overlapping lines due to large line width",
+	    "stroke", /* keywords */
+	    NULL, /* requirements */
+	    SIZE, SIZE,
+	    NULL, draw_flipped)
+CAIRO_TEST (line_width_large_overlap_flopped,
+	    "Test overlapping lines due to large line width",
+	    "stroke", /* keywords */
+	    NULL, /* requirements */
+	    SIZE, SIZE,
+	    NULL, draw_flopped)
+CAIRO_TEST (line_width_large_overlap_dashed,
+	    "Test overlapping lines due to large line width",
+	    "stroke", /* keywords */
+	    NULL, /* requirements */
+	    SIZE, SIZE,
+	    NULL, draw_dashed)