1#include "../test/utils.h"
2#include "gtk-utils.h"
3
4#define NUM_GRADIENTS 9
5#define NUM_STOPS 3
6#define NUM_REPEAT 4
7#define SIZE 128
8#define WIDTH (SIZE * NUM_GRADIENTS)
9#define HEIGHT (SIZE * NUM_REPEAT)
10
11/*
12 * We want to test all the possible relative positions of the start
13 * and end circle:
14 *
15 *  - The start circle can be smaller/equal/bigger than the end
16 *    circle. A radial gradient can be classified in one of these
17 *    three cases depending on the sign of dr.
18 *
19 *  - The smaller circle can be completely inside/internally
20 *    tangent/outside (at least in part) of the bigger circle. This
21 *    classification is the same as the one which can be computed by
22 *    examining the sign of a = (dx^2 + dy^2 - dr^2).
23 *
24 *  - If the two circles have the same size, neither can be inside or
25 *    internally tangent
26 *
27 * This test draws radial gradients whose circles always have the same
28 * centers (0, 0) and (1, 0), but with different radiuses. From left
29 * to right:
30 *
31 * - Degenerate start circle completely inside the end circle
32 *     0.00 -> 1.75; dr = 1.75 > 0; a = 1 - 1.75^2 < 0
33 *
34 * - Small start circle completely inside the end circle
35 *     0.25 -> 1.75; dr =  1.5 > 0; a = 1 - 1.50^2 < 0
36 *
37 * - Small start circle internally tangent to the end circle
38 *     0.50 -> 1.50; dr =  1.0 > 0; a = 1 - 1.00^2 = 0
39 *
40 * - Small start circle outside of the end circle
41 *     0.50 -> 1.00; dr =  0.5 > 0; a = 1 - 0.50^2 > 0
42 *
43 * - Start circle with the same size as the end circle
44 *     1.00 -> 1.00; dr =  0.0 = 0; a = 1 - 0.00^2 > 0
45 *
46 * - Small end circle outside of the start circle
47 *     1.00 -> 0.50; dr = -0.5 > 0; a = 1 - 0.50^2 > 0
48 *
49 * - Small end circle internally tangent to the start circle
50 *     1.50 -> 0.50; dr = -1.0 > 0; a = 1 - 1.00^2 = 0
51 *
52 * - Small end circle completely inside the start circle
53 *     1.75 -> 0.25; dr = -1.5 > 0; a = 1 - 1.50^2 < 0
54 *
55 * - Degenerate end circle completely inside the start circle
56 *     0.00 -> 1.75; dr = 1.75 > 0; a = 1 - 1.75^2 < 0
57 *
58 */
59
60const static double radiuses[NUM_GRADIENTS] = {
61    0.00,
62    0.25,
63    0.50,
64    0.50,
65    1.00,
66    1.00,
67    1.50,
68    1.75,
69    1.75
70};
71
72#define double_to_color(x)					\
73    (((uint32_t) ((x)*65536)) - (((uint32_t) ((x)*65536)) >> 16))
74
75#define PIXMAN_STOP(offset,r,g,b,a)		\
76    { pixman_double_to_fixed (offset),		\
77	{					\
78	double_to_color (r),			\
79	double_to_color (g),			\
80	double_to_color (b),			\
81	double_to_color (a)			\
82	}					\
83    }
84
85static const pixman_gradient_stop_t stops[NUM_STOPS] = {
86    PIXMAN_STOP (0.0,        1, 0, 0, 0.75),
87    PIXMAN_STOP (0.70710678, 0, 1, 0, 0),
88    PIXMAN_STOP (1.0,        0, 0, 1, 1)
89};
90
91static pixman_image_t *
92create_radial (int index)
93{
94    pixman_point_fixed_t p0, p1;
95    pixman_fixed_t r0, r1;
96    double x0, x1, radius0, radius1, left, right, center;
97
98    x0 = 0;
99    x1 = 1;
100    radius0 = radiuses[index];
101    radius1 = radiuses[NUM_GRADIENTS - index - 1];
102
103    /* center the gradient */
104    left = MIN (x0 - radius0, x1 - radius1);
105    right = MAX (x0 + radius0, x1 + radius1);
106    center = (left + right) * 0.5;
107    x0 -= center;
108    x1 -= center;
109
110    /* scale to make it fit within a 1x1 rect centered in (0,0) */
111    x0 *= 0.25;
112    x1 *= 0.25;
113    radius0 *= 0.25;
114    radius1 *= 0.25;
115
116    p0.x = pixman_double_to_fixed (x0);
117    p0.y = pixman_double_to_fixed (0);
118
119    p1.x = pixman_double_to_fixed (x1);
120    p1.y = pixman_double_to_fixed (0);
121
122    r0 = pixman_double_to_fixed (radius0);
123    r1 = pixman_double_to_fixed (radius1);
124
125    return pixman_image_create_radial_gradient (&p0, &p1,
126						r0, r1,
127						stops, NUM_STOPS);
128}
129
130static const pixman_repeat_t repeat[NUM_REPEAT] = {
131    PIXMAN_REPEAT_NONE,
132    PIXMAN_REPEAT_NORMAL,
133    PIXMAN_REPEAT_REFLECT,
134    PIXMAN_REPEAT_PAD
135};
136
137int
138main (int argc, char **argv)
139{
140    pixman_transform_t transform;
141    pixman_image_t *src_img, *dest_img;
142    int i, j;
143
144    enable_divbyzero_exceptions ();
145
146    dest_img = pixman_image_create_bits (PIXMAN_a8r8g8b8,
147					 WIDTH, HEIGHT,
148					 NULL, 0);
149
150    draw_checkerboard (dest_img, 25, 0xffaaaaaa, 0xffbbbbbb);
151
152    pixman_transform_init_identity (&transform);
153
154    /*
155     * The create_radial() function returns gradients centered in the
156     * origin and whose interesting part fits a 1x1 square. We want to
157     * paint these gradients on a SIZExSIZE square and to make things
158     * easier we want the origin in the top-left corner of the square
159     * we want to see.
160     */
161    pixman_transform_translate (NULL, &transform,
162				pixman_double_to_fixed (0.5),
163				pixman_double_to_fixed (0.5));
164
165    pixman_transform_scale (NULL, &transform,
166			    pixman_double_to_fixed (SIZE),
167			    pixman_double_to_fixed (SIZE));
168
169    /*
170     * Gradients are evaluated at the center of each pixel, so we need
171     * to translate by half a pixel to trigger some interesting
172     * cornercases. In particular, the original implementation of PDF
173     * radial gradients tried to divide by 0 when using this transform
174     * on the "tangent circles" cases.
175     */
176    pixman_transform_translate (NULL, &transform,
177				pixman_double_to_fixed (0.5),
178				pixman_double_to_fixed (0.5));
179
180    for (i = 0; i < NUM_GRADIENTS; i++)
181    {
182	src_img = create_radial (i);
183	pixman_image_set_transform (src_img, &transform);
184
185	for (j = 0; j < NUM_REPEAT; j++)
186	{
187	    pixman_image_set_repeat (src_img, repeat[j]);
188
189	    pixman_image_composite32 (PIXMAN_OP_OVER,
190				      src_img,
191				      NULL,
192				      dest_img,
193				      0, 0,
194				      0, 0,
195				      i * SIZE, j * SIZE,
196				      SIZE, SIZE);
197
198	}
199
200	pixman_image_unref (src_img);
201    }
202
203    show_image (dest_img);
204
205    pixman_image_unref (dest_img);
206
207    return 0;
208}
209