| /* cairo - a vector graphics library with display and print output |
| * |
| * Copyright © 2009 Eric Anholt |
| * Copyright © 2009 Chris Wilson |
| * Copyright © 2005,2010 Red Hat, Inc |
| * |
| * This library is free software; you can redistribute it and/or |
| * modify it either under the terms of the GNU Lesser General Public |
| * License version 2.1 as published by the Free Software Foundation |
| * (the "LGPL") or, at your option, under the terms of the Mozilla |
| * Public License Version 1.1 (the "MPL"). If you do not alter this |
| * notice, a recipient may use your version of this file under either |
| * the MPL or the LGPL. |
| * |
| * You should have received a copy of the LGPL along with this library |
| * in the file COPYING-LGPL-2.1; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA |
| * You should have received a copy of the MPL along with this library |
| * in the file COPYING-MPL-1.1 |
| * |
| * The contents of this file are subject to the Mozilla Public License |
| * Version 1.1 (the "License"); you may not use this file except in |
| * compliance with the License. You may obtain a copy of the License at |
| * http://www.mozilla.org/MPL/ |
| * |
| * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY |
| * OF ANY KIND, either express or implied. See the LGPL or the MPL for |
| * the specific language governing rights and limitations. |
| * |
| * The Original Code is the cairo graphics library. |
| * |
| * The Initial Developer of the Original Code is Red Hat, Inc. |
| * |
| * Contributor(s): |
| * Benjamin Otte <otte@gnome.org> |
| * Carl Worth <cworth@cworth.org> |
| * Chris Wilson <chris@chris-wilson.co.uk> |
| * Eric Anholt <eric@anholt.net> |
| */ |
| |
| #include "cairoint.h" |
| |
| #include "cairo-error-private.h" |
| #include "cairo-gl-gradient-private.h" |
| #include "cairo-gl-private.h" |
| |
| |
| static int |
| _cairo_gl_gradient_sample_width (unsigned int n_stops, |
| const cairo_gradient_stop_t *stops) |
| { |
| unsigned int n; |
| int width; |
| |
| width = 8; |
| for (n = 1; n < n_stops; n++) { |
| double dx = stops[n].offset - stops[n-1].offset; |
| double delta, max; |
| int ramp; |
| |
| if (dx == 0) |
| return 1024; /* we need to emulate an infinitely sharp step */ |
| |
| max = fabs (stops[n].color.red - stops[n-1].color.red); |
| |
| delta = fabs (stops[n].color.green - stops[n-1].color.green); |
| if (delta > max) |
| max = delta; |
| |
| delta = fabs (stops[n].color.blue - stops[n-1].color.blue); |
| if (delta > max) |
| max = delta; |
| |
| delta = fabs (stops[n].color.alpha - stops[n-1].color.alpha); |
| if (delta > max) |
| max = delta; |
| |
| ramp = 128 * max / dx; |
| if (ramp > width) |
| width = ramp; |
| } |
| |
| return (width + 7) & -8; |
| } |
| |
| static uint8_t premultiply(double c, double a) |
| { |
| int v = c * a * 256; |
| return v - (v >> 8); |
| } |
| |
| static uint32_t color_stop_to_pixel(const cairo_gradient_stop_t *stop) |
| { |
| uint8_t a, r, g, b; |
| |
| a = stop->color.alpha_short >> 8; |
| r = premultiply(stop->color.red, stop->color.alpha); |
| g = premultiply(stop->color.green, stop->color.alpha); |
| b = premultiply(stop->color.blue, stop->color.alpha); |
| |
| if (_cairo_is_little_endian ()) |
| return a << 24 | r << 16 | g << 8 | b << 0; |
| else |
| return a << 0 | r << 8 | g << 16 | b << 24; |
| } |
| |
| static cairo_status_t |
| _cairo_gl_gradient_render (const cairo_gl_context_t *ctx, |
| unsigned int n_stops, |
| const cairo_gradient_stop_t *stops, |
| void *bytes, |
| int width) |
| { |
| pixman_image_t *gradient, *image; |
| pixman_gradient_stop_t pixman_stops_stack[32]; |
| pixman_gradient_stop_t *pixman_stops; |
| pixman_point_fixed_t p1, p2; |
| unsigned int i; |
| pixman_format_code_t gradient_pixman_format; |
| |
| /* |
| * Ensure that the order of the gradient's components in memory is BGRA. |
| * This is done so that the gradient's pixel data is always suitable for |
| * texture upload using format=GL_BGRA and type=GL_UNSIGNED_BYTE. |
| */ |
| if (_cairo_is_little_endian ()) |
| gradient_pixman_format = PIXMAN_a8r8g8b8; |
| else |
| gradient_pixman_format = PIXMAN_b8g8r8a8; |
| |
| pixman_stops = pixman_stops_stack; |
| if (unlikely (n_stops > ARRAY_LENGTH (pixman_stops_stack))) { |
| pixman_stops = _cairo_malloc_ab (n_stops, |
| sizeof (pixman_gradient_stop_t)); |
| if (unlikely (pixman_stops == NULL)) |
| return _cairo_error (CAIRO_STATUS_NO_MEMORY); |
| } |
| |
| for (i = 0; i < n_stops; i++) { |
| pixman_stops[i].x = _cairo_fixed_16_16_from_double (stops[i].offset); |
| pixman_stops[i].color.red = stops[i].color.red_short; |
| pixman_stops[i].color.green = stops[i].color.green_short; |
| pixman_stops[i].color.blue = stops[i].color.blue_short; |
| pixman_stops[i].color.alpha = stops[i].color.alpha_short; |
| } |
| |
| p1.x = _cairo_fixed_16_16_from_double (0.5); |
| p1.y = 0; |
| p2.x = _cairo_fixed_16_16_from_double (width - 0.5); |
| p2.y = 0; |
| |
| gradient = pixman_image_create_linear_gradient (&p1, &p2, |
| pixman_stops, |
| n_stops); |
| if (pixman_stops != pixman_stops_stack) |
| free (pixman_stops); |
| |
| if (unlikely (gradient == NULL)) |
| return _cairo_error (CAIRO_STATUS_NO_MEMORY); |
| |
| pixman_image_set_filter (gradient, PIXMAN_FILTER_BILINEAR, NULL, 0); |
| pixman_image_set_repeat (gradient, PIXMAN_REPEAT_PAD); |
| |
| image = pixman_image_create_bits (gradient_pixman_format, width, 1, |
| bytes, sizeof(uint32_t)*width); |
| if (unlikely (image == NULL)) { |
| pixman_image_unref (gradient); |
| return _cairo_error (CAIRO_STATUS_NO_MEMORY); |
| } |
| |
| pixman_image_composite32 (PIXMAN_OP_SRC, |
| gradient, NULL, image, |
| 0, 0, |
| 0, 0, |
| 0, 0, |
| width, 1); |
| |
| pixman_image_unref (gradient); |
| pixman_image_unref (image); |
| |
| /* We need to fudge pixel 0 to hold the left-most color stop and not |
| * the neareset stop to the zeroth pixel centre in order to correctly |
| * populate the border color. For completeness, do both edges. |
| */ |
| ((uint32_t*)bytes)[0] = color_stop_to_pixel(&stops[0]); |
| ((uint32_t*)bytes)[width-1] = color_stop_to_pixel(&stops[n_stops-1]); |
| |
| return CAIRO_STATUS_SUCCESS; |
| } |
| |
| static unsigned long |
| _cairo_gl_gradient_hash (unsigned int n_stops, |
| const cairo_gradient_stop_t *stops) |
| { |
| return _cairo_hash_bytes (n_stops, |
| stops, |
| sizeof (cairo_gradient_stop_t) * n_stops); |
| } |
| |
| static cairo_gl_gradient_t * |
| _cairo_gl_gradient_lookup (cairo_gl_context_t *ctx, |
| unsigned long hash, |
| unsigned int n_stops, |
| const cairo_gradient_stop_t *stops) |
| { |
| cairo_gl_gradient_t lookup; |
| |
| lookup.cache_entry.hash = hash, |
| lookup.n_stops = n_stops; |
| lookup.stops = stops; |
| |
| return _cairo_cache_lookup (&ctx->gradients, &lookup.cache_entry); |
| } |
| |
| cairo_bool_t |
| _cairo_gl_gradient_equal (const void *key_a, const void *key_b) |
| { |
| const cairo_gl_gradient_t *a = key_a; |
| const cairo_gl_gradient_t *b = key_b; |
| |
| if (a->n_stops != b->n_stops) |
| return FALSE; |
| |
| return memcmp (a->stops, b->stops, a->n_stops * sizeof (cairo_gradient_stop_t)) == 0; |
| } |
| |
| cairo_int_status_t |
| _cairo_gl_gradient_create (cairo_gl_context_t *ctx, |
| unsigned int n_stops, |
| const cairo_gradient_stop_t *stops, |
| cairo_gl_gradient_t **gradient_out) |
| { |
| unsigned long hash; |
| cairo_gl_gradient_t *gradient; |
| cairo_status_t status; |
| int tex_width; |
| GLint internal_format; |
| void *data; |
| |
| if ((unsigned int) ctx->max_texture_size / 2 <= n_stops) |
| return CAIRO_INT_STATUS_UNSUPPORTED; |
| |
| hash = _cairo_gl_gradient_hash (n_stops, stops); |
| |
| gradient = _cairo_gl_gradient_lookup (ctx, hash, n_stops, stops); |
| if (gradient) { |
| *gradient_out = _cairo_gl_gradient_reference (gradient); |
| return CAIRO_STATUS_SUCCESS; |
| } |
| |
| gradient = malloc (sizeof (cairo_gl_gradient_t) + sizeof (cairo_gradient_stop_t) * (n_stops - 1)); |
| if (gradient == NULL) |
| return _cairo_error (CAIRO_STATUS_NO_MEMORY); |
| |
| tex_width = _cairo_gl_gradient_sample_width (n_stops, stops); |
| if (tex_width > ctx->max_texture_size) |
| tex_width = ctx->max_texture_size; |
| |
| CAIRO_REFERENCE_COUNT_INIT (&gradient->ref_count, 2); |
| gradient->cache_entry.hash = hash; |
| gradient->cache_entry.size = tex_width; |
| gradient->device = &ctx->base; |
| gradient->n_stops = n_stops; |
| gradient->stops = gradient->stops_embedded; |
| memcpy (gradient->stops_embedded, stops, n_stops * sizeof (cairo_gradient_stop_t)); |
| |
| glGenTextures (1, &gradient->tex); |
| _cairo_gl_context_activate (ctx, CAIRO_GL_TEX_TEMP); |
| glBindTexture (ctx->tex_target, gradient->tex); |
| |
| data = _cairo_malloc_ab (tex_width, sizeof (uint32_t)); |
| if (unlikely (data == NULL)) { |
| status = _cairo_error (CAIRO_STATUS_NO_MEMORY); |
| goto cleanup_gradient; |
| } |
| |
| status = _cairo_gl_gradient_render (ctx, n_stops, stops, data, tex_width); |
| if (unlikely (status)) |
| goto cleanup_data; |
| |
| /* |
| * In OpenGL ES 2.0 no format conversion is allowed i.e. 'internalFormat' |
| * must match 'format' in glTexImage2D. |
| */ |
| if (_cairo_gl_get_flavor () == CAIRO_GL_FLAVOR_ES) |
| internal_format = GL_BGRA; |
| else |
| internal_format = GL_RGBA; |
| |
| glTexImage2D (ctx->tex_target, 0, internal_format, tex_width, 1, 0, |
| GL_BGRA, GL_UNSIGNED_BYTE, data); |
| |
| free (data); |
| |
| /* we ignore errors here and just return an uncached gradient */ |
| if (unlikely (_cairo_cache_insert (&ctx->gradients, &gradient->cache_entry))) |
| CAIRO_REFERENCE_COUNT_INIT (&gradient->ref_count, 1); |
| |
| *gradient_out = gradient; |
| return CAIRO_STATUS_SUCCESS; |
| |
| cleanup_data: |
| free (data); |
| cleanup_gradient: |
| free (gradient); |
| return status; |
| } |
| |
| cairo_gl_gradient_t * |
| _cairo_gl_gradient_reference (cairo_gl_gradient_t *gradient) |
| { |
| assert (CAIRO_REFERENCE_COUNT_HAS_REFERENCE (&gradient->ref_count)); |
| |
| _cairo_reference_count_inc (&gradient->ref_count); |
| |
| return gradient; |
| } |
| |
| void |
| _cairo_gl_gradient_destroy (cairo_gl_gradient_t *gradient) |
| { |
| cairo_gl_context_t *ctx; |
| cairo_status_t ignore; |
| |
| assert (CAIRO_REFERENCE_COUNT_HAS_REFERENCE (&gradient->ref_count)); |
| |
| if (! _cairo_reference_count_dec_and_test (&gradient->ref_count)) |
| return; |
| |
| if (_cairo_gl_context_acquire (gradient->device, &ctx) == CAIRO_STATUS_SUCCESS) { |
| /* The gradient my still be active in the last operation, so flush */ |
| _cairo_gl_composite_flush (ctx); |
| glDeleteTextures (1, &gradient->tex); |
| ignore = _cairo_gl_context_release (ctx, CAIRO_STATUS_SUCCESS); |
| } |
| |
| free (gradient); |
| } |