1 /* cairo - a vector graphics library with display and print output
3 * Copyright © 2009 Eric Anholt
4 * Copyright © 2009 Chris Wilson
5 * Copyright © 2005,2010 Red Hat, Inc
7 * This library is free software; you can redistribute it and/or
8 * modify it either under the terms of the GNU Lesser General Public
9 * License version 2.1 as published by the Free Software Foundation
10 * (the "LGPL") or, at your option, under the terms of the Mozilla
11 * Public License Version 1.1 (the "MPL"). If you do not alter this
12 * notice, a recipient may use your version of this file under either
13 * the MPL or the LGPL.
15 * You should have received a copy of the LGPL along with this library
16 * in the file COPYING-LGPL-2.1; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA
18 * You should have received a copy of the MPL along with this library
19 * in the file COPYING-MPL-1.1
21 * The contents of this file are subject to the Mozilla Public License
22 * Version 1.1 (the "License"); you may not use this file except in
23 * compliance with the License. You may obtain a copy of the License at
24 * http://www.mozilla.org/MPL/
26 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
27 * OF ANY KIND, either express or implied. See the LGPL or the MPL for
28 * the specific language governing rights and limitations.
30 * The Original Code is the cairo graphics library.
32 * The Initial Developer of the Original Code is Red Hat, Inc.
35 * Benjamin Otte <otte@gnome.org>
36 * Carl Worth <cworth@cworth.org>
37 * Chris Wilson <chris@chris-wilson.co.uk>
38 * Eric Anholt <eric@anholt.net>
43 #include "cairo-error-private.h"
44 #include "cairo-gl-gradient-private.h"
45 #include "cairo-gl-private.h"
49 _cairo_gl_gradient_sample_width (unsigned int n_stops,
50 const cairo_gradient_stop_t *stops)
56 for (n = 1; n < n_stops; n++) {
57 double dx = stops[n].offset - stops[n-1].offset;
62 return 1024; /* we need to emulate an infinitely sharp step */
64 max = fabs (stops[n].color.red - stops[n-1].color.red);
66 delta = fabs (stops[n].color.green - stops[n-1].color.green);
70 delta = fabs (stops[n].color.blue - stops[n-1].color.blue);
74 delta = fabs (stops[n].color.alpha - stops[n-1].color.alpha);
78 ramp = 128 * max / dx;
83 return (width + 7) & -8;
87 # to avoid warning : defined but not used [-Wunused-function]
88 static uint8_t premultiply(double c, double a)
94 static uint32_t color_stop_to_pixel(const cairo_gradient_stop_t *stop)
98 a = stop->color.alpha_short >> 8;
99 r = premultiply(stop->color.red, stop->color.alpha);
100 g = premultiply(stop->color.green, stop->color.alpha);
101 b = premultiply(stop->color.blue, stop->color.alpha);
103 if (_cairo_is_little_endian ())
104 return a << 24 | r << 16 | g << 8 | b << 0;
106 return a << 0 | r << 8 | g << 16 | b << 24;
110 static cairo_status_t
111 _cairo_gl_gradient_render (const cairo_gl_context_t *ctx,
112 unsigned int n_stops,
113 const cairo_gradient_stop_t *stops,
117 pixman_image_t *gradient, *image;
118 pixman_gradient_stop_t pixman_stops_stack[32];
119 pixman_gradient_stop_t *pixman_stops;
120 pixman_point_fixed_t p1, p2;
122 pixman_format_code_t gradient_pixman_format;
125 * Ensure that the order of the gradient's components in memory is BGRA.
126 * This is done so that the gradient's pixel data is always suitable for
127 * texture upload using format=GL_BGRA and type=GL_UNSIGNED_BYTE.
129 if (_cairo_is_little_endian ())
130 gradient_pixman_format = PIXMAN_a8r8g8b8;
132 gradient_pixman_format = PIXMAN_b8g8r8a8;
134 pixman_stops = pixman_stops_stack;
135 if (unlikely (n_stops > ARRAY_LENGTH (pixman_stops_stack))) {
136 pixman_stops = _cairo_malloc_ab (n_stops,
137 sizeof (pixman_gradient_stop_t));
138 if (unlikely (pixman_stops == NULL))
139 return _cairo_error (CAIRO_STATUS_NO_MEMORY);
142 for (i = 0; i < n_stops; i++) {
143 pixman_stops[i].x = _cairo_fixed_16_16_from_double (stops[i].offset);
144 pixman_stops[i].color.red = stops[i].color.red_short;
145 pixman_stops[i].color.green = stops[i].color.green_short;
146 pixman_stops[i].color.blue = stops[i].color.blue_short;
147 pixman_stops[i].color.alpha = stops[i].color.alpha_short;
150 p1.x = _cairo_fixed_16_16_from_double (0.5);
152 p2.x = _cairo_fixed_16_16_from_double (width - 0.5);
155 gradient = pixman_image_create_linear_gradient (&p1, &p2,
158 if (pixman_stops != pixman_stops_stack)
161 if (unlikely (gradient == NULL))
162 return _cairo_error (CAIRO_STATUS_NO_MEMORY);
164 pixman_image_set_filter (gradient, PIXMAN_FILTER_BILINEAR, NULL, 0);
165 pixman_image_set_repeat (gradient, PIXMAN_REPEAT_PAD);
167 image = pixman_image_create_bits (gradient_pixman_format, width, 1,
168 bytes, sizeof(uint32_t)*width);
169 if (unlikely (image == NULL)) {
170 pixman_image_unref (gradient);
171 return _cairo_error (CAIRO_STATUS_NO_MEMORY);
174 pixman_image_composite32 (PIXMAN_OP_SRC,
175 gradient, NULL, image,
181 pixman_image_unref (gradient);
182 pixman_image_unref (image);
184 /* We need to fudge pixel 0 to hold the left-most color stop and not
185 * the neareset stop to the zeroth pixel centre in order to correctly
186 * populate the border color. For completeness, do both edges.
189 /* This not needed as we have generated pixman pixels by using the
190 * half pixel from left and right border
192 /* ((uint32_t*)bytes)[0] = color_stop_to_pixel(&stops[0]);
193 * ((uint32_t*)bytes)[width-1] = color_stop_to_pixel(&stops[n_stops-1]);
196 return CAIRO_STATUS_SUCCESS;
200 _cairo_gl_gradient_hash (unsigned int n_stops,
201 const cairo_gradient_stop_t *stops)
203 return _cairo_hash_bytes (n_stops,
205 sizeof (cairo_gradient_stop_t) * n_stops);
208 static cairo_gl_gradient_t *
209 _cairo_gl_gradient_lookup (cairo_gl_context_t *ctx,
211 unsigned int n_stops,
212 const cairo_gradient_stop_t *stops)
214 cairo_gl_gradient_t lookup;
216 lookup.cache_entry.hash = hash,
217 lookup.n_stops = n_stops;
218 lookup.stops = stops;
220 return _cairo_cache_lookup (&ctx->gradients, &lookup.cache_entry);
224 _cairo_gl_gradient_equal (const void *key_a, const void *key_b)
226 const cairo_gl_gradient_t *a = key_a;
227 const cairo_gl_gradient_t *b = key_b;
229 if (a->n_stops != b->n_stops)
232 return memcmp (a->stops, b->stops, a->n_stops * sizeof (cairo_gradient_stop_t)) == 0;
236 _cairo_gl_gradient_create (cairo_gl_context_t *ctx,
237 unsigned int n_stops,
238 const cairo_gradient_stop_t *stops,
239 cairo_gl_gradient_t **gradient_out)
242 cairo_gl_gradient_t *gradient;
243 cairo_status_t status;
245 GLint internal_format;
248 if ((unsigned int) ctx->max_texture_size / 2 <= n_stops)
249 return CAIRO_INT_STATUS_UNSUPPORTED;
251 hash = _cairo_gl_gradient_hash (n_stops, stops);
253 gradient = _cairo_gl_gradient_lookup (ctx, hash, n_stops, stops);
255 *gradient_out = _cairo_gl_gradient_reference (gradient);
256 return CAIRO_STATUS_SUCCESS;
259 gradient = malloc (sizeof (cairo_gl_gradient_t) + sizeof (cairo_gradient_stop_t) * (n_stops - 1));
260 if (gradient == NULL)
261 return _cairo_error (CAIRO_STATUS_NO_MEMORY);
263 tex_width = _cairo_gl_gradient_sample_width (n_stops, stops);
264 if (tex_width > ctx->max_texture_size)
265 tex_width = ctx->max_texture_size;
267 CAIRO_REFERENCE_COUNT_INIT (&gradient->ref_count, 2);
268 gradient->cache_entry.hash = hash;
269 gradient->cache_entry.size = tex_width;
270 gradient->device = &ctx->base;
271 gradient->n_stops = n_stops;
272 gradient->stops = gradient->stops_embedded;
273 memcpy (gradient->stops_embedded, stops, n_stops * sizeof (cairo_gradient_stop_t));
276 ctx->dispatch.GenTextures (1, &gradient->tex);
277 _cairo_gl_context_activate (ctx, CAIRO_GL_TEX_TEMP);
278 ctx->dispatch.BindTexture (ctx->tex_target, gradient->tex);
280 data = _cairo_malloc_ab (tex_width, sizeof (uint32_t));
281 if (unlikely (data == NULL)) {
282 status = _cairo_error (CAIRO_STATUS_NO_MEMORY);
283 goto cleanup_gradient;
286 status = _cairo_gl_gradient_render (ctx, n_stops, stops, data, tex_width);
287 if (unlikely (status))
291 * In OpenGL ES 2.0 no format conversion is allowed i.e. 'internalFormat'
292 * must match 'format' in glTexImage2D.
294 if (_cairo_gl_get_flavor (&ctx->dispatch) == CAIRO_GL_FLAVOR_ES2 ||
295 _cairo_gl_get_flavor (&ctx->dispatch) == CAIRO_GL_FLAVOR_ES3)
296 internal_format = GL_BGRA;
298 internal_format = GL_RGBA;
300 ctx->dispatch.TexImage2D (ctx->tex_target, 0, internal_format,
302 GL_BGRA, GL_UNSIGNED_BYTE, data);
307 /* we ignore errors here and just return an uncached gradient */
308 if (unlikely (_cairo_cache_insert (&ctx->gradients, &gradient->cache_entry)))
309 CAIRO_REFERENCE_COUNT_INIT (&gradient->ref_count, 1);
311 *gradient_out = gradient;
312 return CAIRO_STATUS_SUCCESS;
321 cairo_gl_gradient_t *
322 _cairo_gl_gradient_reference (cairo_gl_gradient_t *gradient)
324 assert (CAIRO_REFERENCE_COUNT_HAS_REFERENCE (&gradient->ref_count));
326 _cairo_reference_count_inc (&gradient->ref_count);
332 _cairo_gl_gradient_destroy (cairo_gl_gradient_t *gradient)
334 cairo_gl_context_t *ctx;
335 cairo_status_t ignore;
337 assert (CAIRO_REFERENCE_COUNT_HAS_REFERENCE (&gradient->ref_count));
339 if (! _cairo_reference_count_dec_and_test (&gradient->ref_count))
342 if (_cairo_gl_context_acquire (gradient->device, &ctx) == CAIRO_STATUS_SUCCESS) {
343 /* The gradient my still be active in the last operation, so flush */
344 _cairo_gl_composite_flush (ctx);
345 ctx->dispatch.DeleteTextures (1, &gradient->tex);
346 ignore = _cairo_gl_context_release (ctx, CAIRO_STATUS_SUCCESS);