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Diffstat (limited to 'src/pixman/demos/radial-test.c')
| -rw-r--r-- | src/pixman/demos/radial-test.c | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/src/pixman/demos/radial-test.c b/src/pixman/demos/radial-test.c new file mode 100644 index 0000000..08a367c --- /dev/null +++ b/src/pixman/demos/radial-test.c @@ -0,0 +1,208 @@ +#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; +} |
