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-rw-r--r--test/radial-gradient.c248
1 files changed, 196 insertions, 52 deletions
diff --git a/test/radial-gradient.c b/test/radial-gradient.c
index a6d145c..3ad4bb9 100644
--- a/test/radial-gradient.c
+++ b/test/radial-gradient.c
@@ -26,56 +26,113 @@
#include "cairo-test.h"
-#define NUM_GRADIENTS 4
+#define NUM_GRADIENTS 7
#define NUM_EXTEND 4
-#define SIZE 60
-#define WIDTH (SIZE * NUM_GRADIENTS * NUM_GRADIENTS)
+#define SIZE 120
+#define WIDTH (SIZE * NUM_GRADIENTS)
#define HEIGHT (SIZE * NUM_EXTEND)
-static void
-draw_gradient (cairo_t *cr,
- int x,
- int y,
- int size,
- double r1_offset,
- double r1_radius,
- double r2_offset,
- double r2_radius,
- cairo_extend_t extend)
+typedef void (*composite_t)(cairo_t *cr, cairo_pattern_t *pattern);
+typedef void (*add_stops_t)(cairo_pattern_t *pattern);
+
+/*
+ * We want to test all the possible relative positions of the start
+ * and end circle:
+ *
+ * - The start circle can be smaller/equal/bigger than the end
+ * circle. A radial gradient can be classified in one of these
+ * three cases depending on the sign of dr.
+ *
+ * - The smaller circle can be completely inside/internally
+ * tangent/outside (at least in part) of the bigger circle. This
+ * classification is the same as the one which can be computed by
+ * examining the sign of a = (dx^2 + dy^2 - dr^2).
+ *
+ * - If the two circles have the same size, neither can be inside or
+ * internally tangent
+ *
+ * This test draws radial gradients whose circles always have the same
+ * centers (0, 0) and (1, 0), but with different radiuses. From left
+ * to right:
+ *
+ * - Small start circle completely inside the end circle
+ * 0.25 -> 1.75; dr = 1.5 > 0; a = 1 - 1.50^2 < 0
+ *
+ * - Small start circle internally tangent to the end circle
+ * 0.50 -> 1.50; dr = 1.0 > 0; a = 1 - 1.00^2 = 0
+ *
+ * - Small start circle outside of the end circle
+ * 0.50 -> 1.00; dr = 0.5 > 0; a = 1 - 0.50^2 > 0
+ *
+ * - Start circle with the same size as the end circle
+ * 1.00 -> 1.00; dr = 0.0 = 0; a = 1 - 0.00^2 > 0
+ *
+ * - Small end circle outside of the start circle
+ * 1.00 -> 0.50; dr = -0.5 > 0; a = 1 - 0.50^2 > 0
+ *
+ * - Small end circle internally tangent to the start circle
+ * 1.50 -> 0.50; dr = -1.0 > 0; a = 1 - 1.00^2 = 0
+ *
+ * - Small end circle completely inside the start circle
+ * 1.75 -> 0.25; dr = -1.5 > 0; a = 1 - 1.50^2 < 0
+ *
+ */
+
+const static double radiuses[NUM_GRADIENTS] = {
+ 0.25,
+ 0.50,
+ 0.50,
+ 1.00,
+ 1.00,
+ 1.50,
+ 1.75
+};
+
+static cairo_pattern_t *
+create_pattern (int index)
{
- cairo_pattern_t *pattern;
-
- cairo_save (cr);
-
- pattern = cairo_pattern_create_radial (x + size/2.0 + r1_offset,
- y + size/2.0 + r1_offset,
- r1_radius,
- x + size/2.0 + r2_offset,
- y + size/2.0 + r2_offset,
- r2_radius);
- 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);
+ double x0, x1, radius0, radius1, left, right, center;
- cairo_set_source (cr, pattern);
- cairo_paint (cr);
+ x0 = 0;
+ x1 = 1;
+ radius0 = radiuses[index];
+ radius1 = radiuses[NUM_GRADIENTS - index - 1];
+
+ /* center the gradient */
+ left = fmin (x0 - radius0, x1 - radius1);
+ right = fmax (x0 + radius0, x1 + radius1);
+ center = (left + right) * 0.5;
+ x0 -= center;
+ x1 -= center;
- cairo_pattern_destroy (pattern);
+ /* scale to make it fit within a 1x1 rect centered in (0,0) */
+ x0 *= 0.25;
+ x1 *= 0.25;
+ radius0 *= 0.25;
+ radius1 *= 0.25;
- cairo_restore (cr);
+ return cairo_pattern_create_radial (x0, 0, radius0, x1, 0, radius1);
}
+static void
+pattern_add_stops (cairo_pattern_t *pattern)
+{
+ cairo_pattern_add_color_stop_rgba (pattern, 0.0, 1, 0, 0, 0.75);
+ cairo_pattern_add_color_stop_rgba (pattern, sqrt (0.5), 0, 1, 0, 0);
+ cairo_pattern_add_color_stop_rgba (pattern, 1.0, 0, 0, 1, 1);
+}
+
+static void
+pattern_add_single_stop (cairo_pattern_t *pattern)
+{
+ cairo_pattern_add_color_stop_rgba (pattern, 0.25, 1, 0, 0, 1);
+}
+
+
static cairo_test_status_t
-draw (cairo_t *cr, int width, int height)
+draw (cairo_t *cr, add_stops_t add_stops, composite_t composite)
{
- int i, j, k;
+ int i, j;
cairo_extend_t extend[NUM_EXTEND] = {
CAIRO_EXTEND_NONE,
CAIRO_EXTEND_REPEAT,
@@ -83,30 +140,117 @@ draw (cairo_t *cr, int width, int height)
CAIRO_EXTEND_PAD
};
- cairo_test_paint_checkered (cr);
+ cairo_scale (cr, SIZE, SIZE);
+ cairo_translate (cr, 0.5, 0.5);
for (j = 0; j < NUM_EXTEND; j++) {
+ cairo_save (cr);
for (i = 0; i < NUM_GRADIENTS; i++) {
- double r1_offset = i % 2 ? SIZE / 12.0 : 0.0;
- double r1_radius = i >= NUM_GRADIENTS / 2 ? SIZE / 6.0 : 0.0;
- for (k = 0; k < NUM_GRADIENTS; k++) {
- double r2_offset = k % 2 ? SIZE / 12.0 : 0.0;
- double r2_radius = k >= NUM_GRADIENTS / 2 ? SIZE / 3.0 : SIZE / 12.;
- draw_gradient (cr,
- i * SIZE * NUM_GRADIENTS + k * SIZE, j * SIZE, SIZE,
- r1_offset, r1_radius,
- r2_offset, r2_radius,
- extend[j]);
- }
+ cairo_pattern_t *pattern;
+
+ pattern = create_pattern (i);
+ add_stops (pattern);
+ cairo_pattern_set_extend (pattern, extend[j]);
+
+ cairo_save (cr);
+ cairo_rectangle (cr, -0.5, -0.5, 1, 1);
+ cairo_clip (cr);
+ composite (cr, pattern);
+ cairo_restore (cr);
+ cairo_pattern_destroy (pattern);
+
+ cairo_translate (cr, 1, 0);
}
+ cairo_restore (cr);
+ cairo_translate (cr, 0, 1);
}
return CAIRO_TEST_SUCCESS;
}
+
+static void
+composite_simple (cairo_t *cr, cairo_pattern_t *pattern)
+{
+ cairo_set_source (cr, pattern);
+ cairo_paint (cr);
+}
+
+static void
+composite_mask (cairo_t *cr, cairo_pattern_t *pattern)
+{
+ cairo_set_source_rgb (cr, 1, 0, 1);
+ cairo_mask (cr, pattern);
+}
+
+
+static cairo_test_status_t
+draw_simple (cairo_t *cr, int width, int height)
+{
+ cairo_test_paint_checkered (cr);
+ return draw (cr, pattern_add_stops, composite_simple);
+}
+
+static cairo_test_status_t
+draw_mask (cairo_t *cr, int width, int height)
+{
+ cairo_test_paint_checkered (cr);
+ return draw (cr, pattern_add_stops, composite_mask);
+}
+
+static cairo_test_status_t
+draw_source (cairo_t *cr, int width, int height)
+{
+ cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
+ return draw (cr, pattern_add_stops, composite_simple);
+}
+
+
+static cairo_test_status_t
+draw_mask_source (cairo_t *cr, int width, int height)
+{
+ cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);
+ return draw (cr, pattern_add_stops, composite_mask);
+}
+
+static cairo_test_status_t
+draw_one_stop (cairo_t *cr, int width, int height)
+{
+ cairo_test_paint_checkered (cr);
+ return draw (cr, pattern_add_single_stop, composite_simple);
+}
+
CAIRO_TEST (radial_gradient,
"Simple test of radial gradients",
"gradient", /* keywords */
NULL, /* requirements */
WIDTH, HEIGHT,
- NULL, draw)
+ NULL, draw_simple)
+
+CAIRO_TEST (radial_gradient_mask,
+ "Simple test of radial gradients using a MASK",
+ "gradient,mask", /* keywords */
+ NULL, /* requirements */
+ WIDTH, HEIGHT,
+ NULL, draw_mask)
+
+CAIRO_TEST (radial_gradient_source,
+ "Simple test of radial gradients using the SOURCE operator",
+ "gradient,source", /* keywords */
+ NULL, /* requirements */
+ WIDTH, HEIGHT,
+ NULL, draw_source)
+
+CAIRO_TEST (radial_gradient_mask_source,
+ "Simple test of radial gradients using a MASK with a SOURCE operator",
+ "gradient,mask,source", /* keywords */
+ NULL, /* requirements */
+ WIDTH, HEIGHT,
+ NULL, draw_mask_source)
+
+CAIRO_TEST (radial_gradient_one_stop,
+ "Tests radial gradients with a single stop",
+ "gradient,radial", /* keywords */
+ NULL, /* requirements */
+ WIDTH, HEIGHT,
+ NULL, draw_one_stop)
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-03 17:23:04 +0000