New test case which exposes off-by-one rotation error in pixman.

1 files changed, 78 insertions, 0 deletions

diff --git a/test/pixman-rotate.c b/test/pixman-rotate.c
new file mode 100644
index 000000000..6a64a9a77
--- /dev/null
+++ b/test/pixman-rotate.c
@@ -0,0 +1,78 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+
+#include <cairo.h>
+#include <cairo-png.h>
+#include <cairo-pdf.h>
+
+#include "cairo_test.h"
+
+#define WIDTH	32
+#define HEIGHT	WIDTH
+
+#define IMAGE_WIDTH	(3 * WIDTH)
+#define IMAGE_HEIGHT	IMAGE_WIDTH
+
+cairo_test_t test = {
+    "pixman_rotate",
+    "Exposes pixman off-by-one error when rotating",
+    IMAGE_WIDTH, IMAGE_HEIGHT
+};
+
+/* Draw the word cairo at NUM_TEXT different angles */
+static void
+draw (cairo_t *cr, int width, int height)
+{
+    cairo_surface_t *target, *stamp;
+
+    target = cairo_current_target_surface (cr);
+    cairo_surface_reference (target);
+
+    stamp = cairo_surface_create_similar (target, CAIRO_FORMAT_ARGB32,
+					  WIDTH, HEIGHT);
+    cairo_set_target_surface (cr, stamp);
+    cairo_new_path (cr);
+    cairo_rectangle (cr, WIDTH / 4, HEIGHT / 4, WIDTH / 2, HEIGHT / 2);
+    cairo_set_rgb_color (cr, 1, 0, 0);
+    cairo_set_alpha (cr, 0.8);
+    cairo_fill (cr);
+
+    cairo_rectangle (cr, 0, 0, WIDTH, HEIGHT);
+    cairo_set_line_width (cr, 2);
+    cairo_set_rgb_color (cr, 0, 0, 0);
+    cairo_set_alpha (cr, 1);
+    cairo_stroke (cr);
+
+    cairo_set_target_surface (cr, target);
+
+    /* Draw a translucent rectangle for reference where the rotated
+     * image should be. */
+    cairo_new_path (cr);
+    cairo_rectangle (cr, WIDTH, HEIGHT, WIDTH, HEIGHT);
+    cairo_set_rgb_color (cr, 1, 1, 0);
+    cairo_set_alpha (cr, 0.3);
+    cairo_fill (cr);
+
+#if 1 /* Set to 0 to generate reference image */
+    cairo_translate (cr, 2 * WIDTH, 2 * HEIGHT);
+    cairo_rotate (cr, M_PI);
+#else
+    cairo_translate (cr, WIDTH, HEIGHT);
+#endif
+
+    cairo_set_alpha (cr, 1);
+    cairo_show_surface (cr, stamp, WIDTH + 2, HEIGHT + 2);
+
+    cairo_show_page (cr);
+
+    cairo_surface_destroy (stamp);
+    cairo_surface_destroy (target);
+}
+
+int
+main (void)
+{
+    return cairo_test (&test, draw);
+}