Add radial-gradient test case

Embarrassingly enough, the test suite previously never called
into cairo_pattern_create_radial at all. Unsurprisingly, this
has led to bugs creeping into the radial gradient implementation.

test/.gitignore

@@ -96,6 +96,7 @@ png-flatten
 ps-features
 ps-features.ps
 push-group
+radial-gradient
 random-intersections
 svg2png
 svg-clip

test/Makefile.am

@@ -71,6 +71,7 @@ paint-with-alpha		\
 pattern-get-type		\
 pattern-getters			\
 pixman-rotate			\
+radial-gradient			\
 random-intersections		\
 rectangle-rounding-error	\
 rectilinear-stroke		\

test/radial-gradient.c

@@ -0,0 +1,110 @@
+/*
+ * Copyright © 2005, 2007 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: Carl D. Worth <cworth@cworth.org>
+ */
+
+#include "cairo-test.h"
+
+static cairo_test_draw_function_t draw;
+
+#define NUM_GRADIENTS 4
+#define NUM_EXTEND 4
+#define SIZE 60
+#define WIDTH (SIZE * NUM_GRADIENTS)
+#define HEIGHT (SIZE * NUM_EXTEND)
+
+cairo_test_t test = {
+    "radial-gradient",
+    "Simple test of radial gradients",
+    WIDTH, HEIGHT,
+    draw
+};
+
+static void
+draw_gradient (cairo_t 		*cr,
+	       int		x,
+	       int		y,
+	       int		size,
+	       double		offset,
+	       double		inner_radius,
+	       cairo_extend_t	extend)
+{
+    cairo_pattern_t *pattern;
+
+    cairo_save (cr);
+
+    pattern = cairo_pattern_create_radial (x + size/2.0 + offset,
+					   y + size/2.0 + offset, inner_radius,
+					   x + size/2.0,
+					   y + size/2.0, size/3.0);
+    cairo_pattern_add_color_stop_rgba (pattern, 0.0,
+				       1.0, 0.0, 0.0, 1.0);
+    cairo_pattern_add_color_stop_rgba (pattern, sqrt (1.0 / 2.0),
+				       0.0, 1.0, 0.0, 0.0);
+    cairo_pattern_add_color_stop_rgba (pattern, 1.0,
+				       0.0, 0.0, 1.0, 0.5);
+    cairo_pattern_set_extend (pattern, extend);
+
+    cairo_rectangle (cr, x, y, size, size);
+    cairo_clip (cr);
+
+    cairo_set_source (cr, pattern);
+    cairo_paint (cr);
+
+    cairo_pattern_destroy (pattern);
+
+    cairo_restore (cr);
+}
+
+static cairo_test_status_t
+draw (cairo_t *cr, int width, int height)
+{
+    int i, j;
+    double inner_radius, offset;
+    cairo_extend_t extend[NUM_EXTEND] = {
+	CAIRO_EXTEND_NONE,
+	CAIRO_EXTEND_REPEAT,
+	CAIRO_EXTEND_REFLECT,
+	CAIRO_EXTEND_PAD
+    };
+
+    cairo_test_paint_checkered (cr);
+
+    for (j = 0; j < NUM_EXTEND; j++) {
+	for (i = 0; i < NUM_GRADIENTS; i++) {
+	    offset = i % 2 ? SIZE / 12.0 : 0.0;
+	    inner_radius = i >= NUM_EXTEND / 2 ? SIZE / 6.0 : 0.0;
+	    draw_gradient (cr, i * SIZE, j * SIZE, SIZE,
+			   offset, inner_radius, extend[j]);
+	}
+    }
+
+    return CAIRO_TEST_SUCCESS;
+}
+
+int
+main (void)
+{
+    return cairo_test (&test);
+}