--- /dev/null
+#include "../test/utils.h"
+#include "gtk-utils.h"
+
+#define NUM_GRADIENTS 9
+#define NUM_STOPS 3
+#define NUM_REPEAT 4
+#define SIZE 128
+#define WIDTH (SIZE * NUM_GRADIENTS)
+#define HEIGHT (SIZE * NUM_REPEAT)
+
+/*
+ * 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:
+ *
+ * - Degenerate start circle completely inside the end circle
+ * 0.00 -> 1.75; dr = 1.75 > 0; a = 1 - 1.75^2 < 0
+ *
+ * - 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
+ *
+ * - Degenerate end circle completely inside the start circle
+ * 0.00 -> 1.75; dr = 1.75 > 0; a = 1 - 1.75^2 < 0
+ *
+ */
+
+const static double radiuses[NUM_GRADIENTS] = {
+ 0.00,
+ 0.25,
+ 0.50,
+ 0.50,
+ 1.00,
+ 1.00,
+ 1.50,
+ 1.75,
+ 1.75
+};
+
+#define double_to_color(x) \
+ (((uint32_t) ((x)*65536)) - (((uint32_t) ((x)*65536)) >> 16))
+
+#define PIXMAN_STOP(offset,r,g,b,a) \
+ { pixman_double_to_fixed (offset), \
+ { \
+ double_to_color (r), \
+ double_to_color (g), \
+ double_to_color (b), \
+ double_to_color (a) \
+ } \
+ }
+
+static const pixman_gradient_stop_t stops[NUM_STOPS] = {
+ PIXMAN_STOP (0.0, 1, 0, 0, 0.75),
+ PIXMAN_STOP (0.70710678, 0, 1, 0, 0),
+ PIXMAN_STOP (1.0, 0, 0, 1, 1)
+};
+
+static pixman_image_t *
+create_radial (int index)
+{
+ pixman_point_fixed_t p0, p1;
+ pixman_fixed_t r0, r1;
+ double x0, x1, radius0, radius1, left, right, center;
+
+ x0 = 0;
+ x1 = 1;
+ radius0 = radiuses[index];
+ radius1 = radiuses[NUM_GRADIENTS - index - 1];
+
+ /* center the gradient */
+ left = MIN (x0 - radius0, x1 - radius1);
+ right = MAX (x0 + radius0, x1 + radius1);
+ center = (left + right) * 0.5;
+ x0 -= center;
+ x1 -= center;
+
+ /* 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;
+
+ p0.x = pixman_double_to_fixed (x0);
+ p0.y = pixman_double_to_fixed (0);
+
+ p1.x = pixman_double_to_fixed (x1);
+ p1.y = pixman_double_to_fixed (0);
+
+ r0 = pixman_double_to_fixed (radius0);
+ r1 = pixman_double_to_fixed (radius1);
+
+ return pixman_image_create_radial_gradient (&p0, &p1,
+ r0, r1,
+ stops, NUM_STOPS);
+}
+
+static const pixman_repeat_t repeat[NUM_REPEAT] = {
+ PIXMAN_REPEAT_NONE,
+ PIXMAN_REPEAT_NORMAL,
+ PIXMAN_REPEAT_REFLECT,
+ PIXMAN_REPEAT_PAD
+};
+
+int
+main (int argc, char **argv)
+{
+ pixman_transform_t transform;
+ pixman_image_t *src_img, *dest_img;
+ int i, j;
+
+ enable_divbyzero_exceptions ();
+
+ dest_img = pixman_image_create_bits (PIXMAN_a8r8g8b8,
+ WIDTH, HEIGHT,
+ NULL, 0);
+
+ draw_checkerboard (dest_img, 25, 0xffaaaaaa, 0xffbbbbbb);
+
+ pixman_transform_init_identity (&transform);
+
+ /*
+ * The create_radial() function returns gradients centered in the
+ * origin and whose interesting part fits a 1x1 square. We want to
+ * paint these gradients on a SIZExSIZE square and to make things
+ * easier we want the origin in the top-left corner of the square
+ * we want to see.
+ */
+ pixman_transform_translate (NULL, &transform,
+ pixman_double_to_fixed (0.5),
+ pixman_double_to_fixed (0.5));
+
+ pixman_transform_scale (NULL, &transform,
+ pixman_double_to_fixed (SIZE),
+ pixman_double_to_fixed (SIZE));
+
+ /*
+ * Gradients are evaluated at the center of each pixel, so we need
+ * to translate by half a pixel to trigger some interesting
+ * cornercases. In particular, the original implementation of PDF
+ * radial gradients tried to divide by 0 when using this transform
+ * on the "tangent circles" cases.
+ */
+ pixman_transform_translate (NULL, &transform,
+ pixman_double_to_fixed (0.5),
+ pixman_double_to_fixed (0.5));
+
+ for (i = 0; i < NUM_GRADIENTS; i++)
+ {
+ src_img = create_radial (i);
+ pixman_image_set_transform (src_img, &transform);
+
+ for (j = 0; j < NUM_REPEAT; j++)
+ {
+ pixman_image_set_repeat (src_img, repeat[j]);
+
+ pixman_image_composite32 (PIXMAN_OP_OVER,
+ src_img,
+ NULL,
+ dest_img,
+ 0, 0,
+ 0, 0,
+ i * SIZE, j * SIZE,
+ SIZE, SIZE);
+
+ }
+
+ pixman_image_unref (src_img);
+ }
+
+ show_image (dest_img);
+
+ pixman_image_unref (dest_img);
+
+ return 0;
+}
Code Review / kvmfornfv.git / blobdiff