Comment and clean up the gradient computation. (_cairo_linear_pattern_classify): Determine if a linear gradient is horizontal or vertical. (_cairo_pattern_acquire_surface_for_gradient): Optimize horizontal/vertical gradients with a repeating surface.

Test case for linear gradients at angles and with a rotated pattern matrix.

1 files changed, 141 insertions, 0 deletions

diff --git a/test/linear-gradient.c b/test/linear-gradient.c
new file mode 100644
index 000000000..189b50065
--- /dev/null
+++ b/test/linear-gradient.c
@@ -0,0 +1,141 @@
+/*
+ * Copyright © 2005 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: Owen Taylor <otaylor@redhat.com>
+ */
+
+#include "cairo_test.h"
+#include "stdio.h"
+
+/* The test matrix is
+ *
+ * A) Horizontal   B) 5°          C) 45°          D) Vertical
+ * 1) Rotated 0°   2) Rotated 45° C) Rotated 90°
+ * a) 2 stop       b) 3 stop
+ *
+ *  A1a   B1a  C1a  D1a
+ *  A2a   B2a  C2a  D2a
+ *  A3a   B3a  C3a  D3a
+ *  A1b   B1b  C1b  D1b
+ *  A2b   B2b  C2b  D2b
+ *  A3b   B3b  C3b  D3b
+ */
+
+static const double gradient_angles[] = { 0, 45, 90 };
+#define N_GRADIENT_ANGLES 3
+static const double rotate_angles[] = { 0, 45, 90 };
+#define N_ROTATE_ANGLES 3
+static const int n_stops[] = { 2, 3 };
+#define N_N_STOPS 2
+
+#define UNIT_SIZE 75
+#define UNIT_SIZE 75
+#define PAD 5
+
+#define WIDTH  N_GRADIENT_ANGLES * UNIT_SIZE + (N_GRADIENT_ANGLES + 1) * PAD
+#define HEIGHT N_N_STOPS * N_ROTATE_ANGLES * UNIT_SIZE + (N_N_STOPS * N_ROTATE_ANGLES + 1) * PAD
+
+cairo_test_t test = {
+    "linear_gradient",
+    "Tests the drawing of linear gradients",
+    WIDTH, HEIGHT
+};
+
+static void
+draw_unit (cairo_t *cr,
+	   double   gradient_angle,
+	   double   rotate_angle,
+	   int      n_stops)
+{
+    cairo_pattern_t *pattern;
+
+    cairo_rectangle (cr, 0, 0, 1, 1);
+    cairo_clip (cr);
+    cairo_new_path(cr);
+    
+    cairo_set_rgb_color (cr, 0.0, 0.0, 0.0);
+    cairo_rectangle (cr, 0, 0, 1, 1);
+    cairo_fill (cr);
+    
+    cairo_translate (cr, 0.5, 0.5);
+    cairo_scale (cr, 1 / 1.5, 1 / 1.5);
+    cairo_rotate (cr, rotate_angle);
+    
+    pattern = cairo_pattern_create_linear (-0.5 * cos (gradient_angle),  -0.5 * sin (gradient_angle),
+ 					    0.5 * cos (gradient_angle),   0.5 * sin (gradient_angle));
+
+    if (n_stops == 2) {
+	cairo_pattern_add_color_stop (pattern, 0.,
+				      0.3, 0.3, 0.3,
+				      1.0);
+	cairo_pattern_add_color_stop (pattern, 1.,
+				      1.0, 1.0, 1.0,
+				      1.0);
+    } else {
+	cairo_pattern_add_color_stop (pattern, 0.,
+				      1.0, 0.0, 0.0,
+				      1.0);
+	cairo_pattern_add_color_stop (pattern, 0.5,
+				      1.0, 1.0, 1.0,
+				      1.0);
+	cairo_pattern_add_color_stop (pattern, 1.,
+				      0.0, 0.0, 1.0,
+				      1.0);
+    }
+
+    cairo_set_pattern (cr, pattern);
+    cairo_pattern_destroy (pattern);
+    cairo_rectangle (cr, -0.5, -0.5, 1, 1);
+    cairo_fill (cr);
+}
+
+static void
+draw (cairo_t *cr, int width, int height)
+{
+    int i, j, k;
+
+    cairo_set_rgb_color (cr, 0.5, 0.5, 0.5);
+    cairo_rectangle (cr, 0, 0, width, height);
+    cairo_fill (cr);
+
+    for (i = 0; i < N_GRADIENT_ANGLES; i++)
+	for (j = 0; j < N_ROTATE_ANGLES; j++)
+	  for (k = 0; k < N_N_STOPS; k++) {
+		cairo_save (cr);
+		cairo_translate (cr,
+				 PAD + (PAD + UNIT_SIZE) * i,
+				 PAD + (PAD + UNIT_SIZE) * (N_ROTATE_ANGLES * k + j));
+		cairo_scale (cr, UNIT_SIZE, UNIT_SIZE);
+		
+		draw_unit (cr,
+			   gradient_angles[i] * M_PI / 180.,
+			   rotate_angles[j] * M_PI / 180.,
+			   n_stops[k]);
+		cairo_restore (cr);
+	    }
+}
+
+int
+main (void)
+{
+    return cairo_test (&test, draw);
+}