Augment tests to do better testing of paths/images with alpha.

Add a new cairo_test_paint_checkered function so that tests that draw
with alpha can easily put an easy-to-see checkered background in place
first.

Add new tests caps-joins-alpha and paint-source-alpha that do simple
tests of strokes and image painting with source pattern alpha.

Also, add the checkered background to paint-with-alpha for
consistency.

1 files changed, 67 insertions, 0 deletions

diff --git a/test/paint-source-alpha.c b/test/paint-source-alpha.c
new file mode 100644
index 000000000..8971939a0
--- /dev/null
+++ b/test/paint-source-alpha.c
@@ -0,0 +1,67 @@
+/*
+ * Copyright © 2005 Red Hat, Inc.
+ * Copyright © 2006 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: Carl D. Worth <cworth@cworth.org>
+ */
+
+#include "cairo-test.h"
+
+cairo_test_t test = {
+    "paint-source-alpha",
+    "Simple test of cairo_paint with a source surface with non-opaque alpha",
+    32, 32
+};
+
+static cairo_test_status_t
+draw (cairo_t *cr, int width, int height)
+{
+    cairo_surface_t *surface;
+    static uint32_t data[16] = {
+	0x80808080, 0x80808080,		0x80800000, 0x80800000,
+	0x80808080, 0x80808080,		0x80800000, 0x80800000,
+
+	0x80008000, 0x80008000,		0x80000080, 0x80000080,
+	0x80008000, 0x80008000,		0x80000080, 0x80000080
+    };
+
+    surface = cairo_image_surface_create_for_data ((unsigned char *) data,
+						   CAIRO_FORMAT_ARGB32, 4, 4, 16);
+
+    cairo_test_paint_checkered (cr);
+
+    cairo_scale (cr, 4, 4);
+
+    cairo_set_source_surface (cr, surface, 2 , 2);
+    cairo_pattern_set_filter (cairo_get_source (cr), CAIRO_FILTER_NEAREST);
+    cairo_paint (cr);
+
+    cairo_surface_destroy (surface);
+
+    return CAIRO_TEST_SUCCESS;
+}
+
+int
+main (void)
+{
+    return cairo_test (&test, draw);
+}