test: Add tests for mesh patterns

mesh-pattern tests a mesh pattern with non-opaque two overlapping
patches.

mesh-pattern-accuracy tests the accuracy of the color computed in each
point of a patch. It can point out defects in rasterizers which rely
on mesh subdivision only use the mesh shape instead of both shape and
color to decide when the tensor-product patches can be approximated
with Gouraud-shaded triangles.

mesh-pattern-conical is an example of how a conical gradient can be
approximated with a mesh pattern.

mesh-pattern-control-points tests a mesh pattern with control points
in non-default position to verify that their position affects the
color as expected.

mesh-pattern-fold tests a mesh pattern with a patch which folds along
both sides.

mesh-pattern-overlap tests a mesh pattern with a patch which folds
along just one side.

mesh-pattern-transformed tests a mesh pattern with non-identity
transform matrix.

1 files changed, 114 insertions, 0 deletions

diff --git a/test/mesh-pattern-control-points.c b/test/mesh-pattern-control-points.c
new file mode 100644
index 000000000..54ff850e0
--- /dev/null
+++ b/test/mesh-pattern-control-points.c
@@ -0,0 +1,114 @@
+/*
+ * Copyright © 2009 Adrian Johnson
+ *
+ * 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: Adrian Johnson <ajohnson@redneon.com>
+ */
+
+#include "cairo-test.h"
+
+#define SIZE 90
+#define PAD 10
+#define WIDTH (PAD + 2 * (SIZE + PAD))
+#define HEIGHT (PAD + SIZE + PAD)
+
+
+/*
+ * This test is designed to paint a two mesh patches. One with default
+ * control points and one with a control point at a no default
+ * location.  The control points of both of them are drawn as squares
+ * to make them visible.
+ */
+
+static cairo_test_status_t
+draw (cairo_t *cr, int width, int height)
+{
+    cairo_pattern_t *pattern;
+    unsigned int i, j;
+    unsigned int num_patches;
+    double x, y;
+
+    cairo_set_source_rgb (cr, 1, 1, 1);
+    cairo_paint (cr);
+
+    cairo_translate (cr, PAD, PAD);
+
+    pattern = cairo_pattern_create_mesh ();
+    cairo_pattern_mesh_begin_patch (pattern);
+
+    cairo_pattern_mesh_move_to (pattern,    0,    0);
+    cairo_pattern_mesh_line_to (pattern, SIZE,    0);
+    cairo_pattern_mesh_line_to (pattern, SIZE, SIZE);
+    cairo_pattern_mesh_line_to (pattern,    0, SIZE);
+
+    cairo_pattern_mesh_set_corner_color_rgb (pattern, 0, 1, 0, 0);
+    cairo_pattern_mesh_set_corner_color_rgb (pattern, 1, 0, 1, 0);
+    cairo_pattern_mesh_set_corner_color_rgb (pattern, 2, 0, 0, 1);
+    cairo_pattern_mesh_set_corner_color_rgb (pattern, 3, 1, 1, 0);
+
+    cairo_pattern_mesh_set_control_point (pattern, 0, SIZE * .7, SIZE * .7);
+    cairo_pattern_mesh_set_control_point (pattern, 1, SIZE * .9, SIZE * .7);
+    cairo_pattern_mesh_set_control_point (pattern, 2, SIZE * .9, SIZE * .9);
+    cairo_pattern_mesh_set_control_point (pattern, 3, SIZE * .7, SIZE * .9);
+
+    cairo_pattern_mesh_end_patch (pattern);
+
+    cairo_pattern_mesh_begin_patch (pattern);
+
+    cairo_pattern_mesh_move_to (pattern,   SIZE + PAD,    0);
+    cairo_pattern_mesh_line_to (pattern, 2*SIZE + PAD,    0);
+    cairo_pattern_mesh_line_to (pattern, 2*SIZE + PAD, SIZE);
+    cairo_pattern_mesh_line_to (pattern,   SIZE + PAD, SIZE);
+
+    cairo_pattern_mesh_set_corner_color_rgb (pattern, 0, 1, 0, 0);
+    cairo_pattern_mesh_set_corner_color_rgb (pattern, 1, 0, 1, 0);
+    cairo_pattern_mesh_set_corner_color_rgb (pattern, 2, 0, 0, 1);
+    cairo_pattern_mesh_set_corner_color_rgb (pattern, 3, 1, 1, 0);
+
+    cairo_pattern_mesh_end_patch (pattern);
+
+    cairo_set_source (cr, pattern);
+    cairo_paint (cr);
+
+    /* mark the location of the control points */
+    cairo_set_source_rgb (cr, 0, 0, 0);
+    cairo_pattern_mesh_get_patch_count (pattern, &num_patches);
+    for (i = 0; i < num_patches; i++) {
+	for (j = 0; j < 4; j++) {
+	    cairo_pattern_mesh_get_control_point (pattern, i, j, &x, &y);
+	    cairo_rectangle (cr, x - 5, y - 5, 10, 10);
+	    cairo_fill (cr);
+	}
+    }
+
+    cairo_pattern_destroy (pattern);
+
+    return CAIRO_TEST_SUCCESS;
+}
+
+
+CAIRO_TEST (mesh_pattern_control_points,
+	    "Paint mesh pattern with non default control points",
+	    "mesh,pattern", /* keywords */
+	    NULL, /* requirements */
+	    WIDTH, HEIGHT,
+	    NULL, draw)