1 /*
2 * Copyright © 2000 SuSE, Inc.
3 * Copyright © 2007 Red Hat, Inc.
4 * Copyright © 2000 Keith Packard, member of The XFree86 Project, Inc.
5 * 2005 Lars Knoll & Zack Rusin, Trolltech
6 *
7 * Permission to use, copy, modify, distribute, and sell this software and its
8 * documentation for any purpose is hereby granted without fee, provided that
9 * the above copyright notice appear in all copies and that both that
10 * copyright notice and this permission notice appear in supporting
11 * documentation, and that the name of Keith Packard not be used in
12 * advertising or publicity pertaining to distribution of the software without
13 * specific, written prior permission. Keith Packard makes no
14 * representations about the suitability of this software for any purpose. It
15 * is provided "as is" without express or implied warranty.
16 *
17 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
18 * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
19 * FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
20 * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
21 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
22 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
23 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
24 * SOFTWARE.
25 */
26
27 #ifdef HAVE_CONFIG_H
28 #include <config.h>
29 #endif
30
31 #include <stdlib.h>
32 #include <math.h>
33 #include "pixman-private.h"
34
35 static force_inline double
coordinates_to_parameter(double x,double y,double angle)36 coordinates_to_parameter (double x, double y, double angle)
37 {
38 double t;
39
40 t = atan2 (y, x) + angle;
41
42 while (t < 0)
43 t += 2 * M_PI;
44
45 while (t >= 2 * M_PI)
46 t -= 2 * M_PI;
47
48 return 1 - t * (1 / (2 * M_PI)); /* Scale t to [0, 1] and
49 * make rotation CCW
50 */
51 }
52
53 static uint32_t *
conical_get_scanline_narrow(pixman_iter_t * iter,const uint32_t * mask)54 conical_get_scanline_narrow (pixman_iter_t *iter, const uint32_t *mask)
55 {
56 pixman_image_t *image = iter->image;
57 int x = iter->x;
58 int y = iter->y;
59 int width = iter->width;
60 uint32_t *buffer = iter->buffer;
61
62 gradient_t *gradient = (gradient_t *)image;
63 conical_gradient_t *conical = (conical_gradient_t *)image;
64 uint32_t *end = buffer + width;
65 pixman_gradient_walker_t walker;
66 pixman_bool_t affine = TRUE;
67 double cx = 1.;
68 double cy = 0.;
69 double cz = 0.;
70 double rx = x + 0.5;
71 double ry = y + 0.5;
72 double rz = 1.;
73
74 _pixman_gradient_walker_init (&walker, gradient, image->common.repeat);
75
76 if (image->common.transform)
77 {
78 pixman_vector_t v;
79
80 /* reference point is the center of the pixel */
81 v.vector[0] = pixman_int_to_fixed (x) + pixman_fixed_1 / 2;
82 v.vector[1] = pixman_int_to_fixed (y) + pixman_fixed_1 / 2;
83 v.vector[2] = pixman_fixed_1;
84
85 if (!pixman_transform_point_3d (image->common.transform, &v))
86 return iter->buffer;
87
88 cx = image->common.transform->matrix[0][0] / 65536.;
89 cy = image->common.transform->matrix[1][0] / 65536.;
90 cz = image->common.transform->matrix[2][0] / 65536.;
91
92 rx = v.vector[0] / 65536.;
93 ry = v.vector[1] / 65536.;
94 rz = v.vector[2] / 65536.;
95
96 affine =
97 image->common.transform->matrix[2][0] == 0 &&
98 v.vector[2] == pixman_fixed_1;
99 }
100
101 if (affine)
102 {
103 rx -= conical->center.x / 65536.;
104 ry -= conical->center.y / 65536.;
105
106 while (buffer < end)
107 {
108 if (!mask || *mask++)
109 {
110 double t = coordinates_to_parameter (rx, ry, conical->angle);
111
112 *buffer = _pixman_gradient_walker_pixel (
113 &walker, (pixman_fixed_48_16_t)pixman_double_to_fixed (t));
114 }
115
116 ++buffer;
117
118 rx += cx;
119 ry += cy;
120 }
121 }
122 else
123 {
124 while (buffer < end)
125 {
126 double x, y;
127
128 if (!mask || *mask++)
129 {
130 double t;
131
132 if (rz != 0)
133 {
134 x = rx / rz;
135 y = ry / rz;
136 }
137 else
138 {
139 x = y = 0.;
140 }
141
142 x -= conical->center.x / 65536.;
143 y -= conical->center.y / 65536.;
144
145 t = coordinates_to_parameter (x, y, conical->angle);
146
147 *buffer = _pixman_gradient_walker_pixel (
148 &walker, (pixman_fixed_48_16_t)pixman_double_to_fixed (t));
149 }
150
151 ++buffer;
152
153 rx += cx;
154 ry += cy;
155 rz += cz;
156 }
157 }
158
159 iter->y++;
160 return iter->buffer;
161 }
162
163 static uint32_t *
conical_get_scanline_wide(pixman_iter_t * iter,const uint32_t * mask)164 conical_get_scanline_wide (pixman_iter_t *iter, const uint32_t *mask)
165 {
166 uint32_t *buffer = conical_get_scanline_narrow (iter, NULL);
167
168 pixman_expand_to_float (
169 (argb_t *)buffer, buffer, PIXMAN_a8r8g8b8, iter->width);
170
171 return buffer;
172 }
173
174 void
_pixman_conical_gradient_iter_init(pixman_image_t * image,pixman_iter_t * iter)175 _pixman_conical_gradient_iter_init (pixman_image_t *image, pixman_iter_t *iter)
176 {
177 if (iter->iter_flags & ITER_NARROW)
178 iter->get_scanline = conical_get_scanline_narrow;
179 else
180 iter->get_scanline = conical_get_scanline_wide;
181 }
182
183 PIXMAN_EXPORT pixman_image_t *
pixman_image_create_conical_gradient(const pixman_point_fixed_t * center,pixman_fixed_t angle,const pixman_gradient_stop_t * stops,int n_stops)184 pixman_image_create_conical_gradient (const pixman_point_fixed_t * center,
185 pixman_fixed_t angle,
186 const pixman_gradient_stop_t *stops,
187 int n_stops)
188 {
189 pixman_image_t *image = _pixman_image_allocate ();
190 conical_gradient_t *conical;
191
192 if (!image)
193 return NULL;
194
195 conical = &image->conical;
196
197 if (!_pixman_init_gradient (&conical->common, stops, n_stops))
198 {
199 free (image);
200 return NULL;
201 }
202
203 angle = MOD (angle, pixman_int_to_fixed (360));
204
205 image->type = CONICAL;
206
207 conical->center = *center;
208 conical->angle = (pixman_fixed_to_double (angle) / 180.0) * M_PI;
209
210 return image;
211 }
212
213