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3959 | Serge | 1 | /* cairo - a vector graphics library with display and print output |
2 | * |
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3 | * Copyright © 2009 Eric Anholt |
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4 | * Copyright © 2009 Chris Wilson |
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5 | * Copyright © 2005,2010 Red Hat, Inc |
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6 | * |
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7 | * This library is free software; you can redistribute it and/or |
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8 | * modify it either under the terms of the GNU Lesser General Public |
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9 | * License version 2.1 as published by the Free Software Foundation |
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10 | * (the "LGPL") or, at your option, under the terms of the Mozilla |
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11 | * Public License Version 1.1 (the "MPL"). If you do not alter this |
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12 | * notice, a recipient may use your version of this file under either |
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13 | * the MPL or the LGPL. |
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14 | * |
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15 | * You should have received a copy of the LGPL along with this library |
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16 | * in the file COPYING-LGPL-2.1; if not, write to the Free Software |
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17 | * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA |
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18 | * You should have received a copy of the MPL along with this library |
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19 | * in the file COPYING-MPL-1.1 |
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20 | * |
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21 | * The contents of this file are subject to the Mozilla Public License |
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22 | * Version 1.1 (the "License"); you may not use this file except in |
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23 | * compliance with the License. You may obtain a copy of the License at |
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24 | * http://www.mozilla.org/MPL/ |
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25 | * |
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26 | * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY |
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27 | * OF ANY KIND, either express or implied. See the LGPL or the MPL for |
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28 | * the specific language governing rights and limitations. |
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29 | * |
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30 | * The Original Code is the cairo graphics library. |
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31 | * |
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32 | * The Initial Developer of the Original Code is Red Hat, Inc. |
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33 | * |
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34 | * Contributor(s): |
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35 | * Benjamin Otte |
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36 | * Carl Worth |
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37 | * Chris Wilson |
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38 | * Eric Anholt |
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39 | */ |
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40 | |||
41 | #include "cairoint.h" |
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42 | |||
43 | #include "cairo-error-private.h" |
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44 | #include "cairo-gl-gradient-private.h" |
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45 | #include "cairo-gl-private.h" |
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46 | |||
47 | |||
48 | static int |
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49 | _cairo_gl_gradient_sample_width (unsigned int n_stops, |
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50 | const cairo_gradient_stop_t *stops) |
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51 | { |
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52 | unsigned int n; |
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53 | int width; |
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54 | |||
55 | width = 8; |
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56 | for (n = 1; n < n_stops; n++) { |
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57 | double dx = stops[n].offset - stops[n-1].offset; |
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58 | double delta, max; |
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59 | int ramp; |
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60 | |||
61 | if (dx == 0) |
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62 | return 1024; /* we need to emulate an infinitely sharp step */ |
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63 | |||
64 | max = fabs (stops[n].color.red - stops[n-1].color.red); |
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65 | |||
66 | delta = fabs (stops[n].color.green - stops[n-1].color.green); |
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67 | if (delta > max) |
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68 | max = delta; |
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69 | |||
70 | delta = fabs (stops[n].color.blue - stops[n-1].color.blue); |
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71 | if (delta > max) |
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72 | max = delta; |
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73 | |||
74 | delta = fabs (stops[n].color.alpha - stops[n-1].color.alpha); |
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75 | if (delta > max) |
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76 | max = delta; |
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77 | |||
78 | ramp = 128 * max / dx; |
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79 | if (ramp > width) |
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80 | width = ramp; |
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81 | } |
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82 | |||
83 | return (width + 7) & -8; |
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84 | } |
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85 | |||
86 | static uint8_t premultiply(double c, double a) |
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87 | { |
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88 | int v = c * a * 256; |
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89 | return v - (v >> 8); |
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90 | } |
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91 | |||
92 | static uint32_t color_stop_to_pixel(const cairo_gradient_stop_t *stop) |
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93 | { |
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94 | uint8_t a, r, g, b; |
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95 | |||
96 | a = stop->color.alpha_short >> 8; |
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97 | r = premultiply(stop->color.red, stop->color.alpha); |
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98 | g = premultiply(stop->color.green, stop->color.alpha); |
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99 | b = premultiply(stop->color.blue, stop->color.alpha); |
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100 | |||
101 | if (_cairo_is_little_endian ()) |
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102 | return a << 24 | r << 16 | g << 8 | b << 0; |
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103 | else |
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104 | return a << 0 | r << 8 | g << 16 | b << 24; |
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105 | } |
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106 | |||
107 | static cairo_status_t |
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108 | _cairo_gl_gradient_render (const cairo_gl_context_t *ctx, |
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109 | unsigned int n_stops, |
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110 | const cairo_gradient_stop_t *stops, |
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111 | void *bytes, |
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112 | int width) |
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113 | { |
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114 | pixman_image_t *gradient, *image; |
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115 | pixman_gradient_stop_t pixman_stops_stack[32]; |
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116 | pixman_gradient_stop_t *pixman_stops; |
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117 | pixman_point_fixed_t p1, p2; |
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118 | unsigned int i; |
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119 | pixman_format_code_t gradient_pixman_format; |
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120 | |||
121 | /* |
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122 | * Ensure that the order of the gradient's components in memory is BGRA. |
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123 | * This is done so that the gradient's pixel data is always suitable for |
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124 | * texture upload using format=GL_BGRA and type=GL_UNSIGNED_BYTE. |
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125 | */ |
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126 | if (_cairo_is_little_endian ()) |
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127 | gradient_pixman_format = PIXMAN_a8r8g8b8; |
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128 | else |
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129 | gradient_pixman_format = PIXMAN_b8g8r8a8; |
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130 | |||
131 | pixman_stops = pixman_stops_stack; |
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132 | if (unlikely (n_stops > ARRAY_LENGTH (pixman_stops_stack))) { |
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133 | pixman_stops = _cairo_malloc_ab (n_stops, |
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134 | sizeof (pixman_gradient_stop_t)); |
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135 | if (unlikely (pixman_stops == NULL)) |
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136 | return _cairo_error (CAIRO_STATUS_NO_MEMORY); |
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137 | } |
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138 | |||
139 | for (i = 0; i < n_stops; i++) { |
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140 | pixman_stops[i].x = _cairo_fixed_16_16_from_double (stops[i].offset); |
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141 | pixman_stops[i].color.red = stops[i].color.red_short; |
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142 | pixman_stops[i].color.green = stops[i].color.green_short; |
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143 | pixman_stops[i].color.blue = stops[i].color.blue_short; |
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144 | pixman_stops[i].color.alpha = stops[i].color.alpha_short; |
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145 | } |
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146 | |||
147 | p1.x = _cairo_fixed_16_16_from_double (0.5); |
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148 | p1.y = 0; |
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149 | p2.x = _cairo_fixed_16_16_from_double (width - 0.5); |
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150 | p2.y = 0; |
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151 | |||
152 | gradient = pixman_image_create_linear_gradient (&p1, &p2, |
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153 | pixman_stops, |
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154 | n_stops); |
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155 | if (pixman_stops != pixman_stops_stack) |
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156 | free (pixman_stops); |
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157 | |||
158 | if (unlikely (gradient == NULL)) |
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159 | return _cairo_error (CAIRO_STATUS_NO_MEMORY); |
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160 | |||
161 | pixman_image_set_filter (gradient, PIXMAN_FILTER_BILINEAR, NULL, 0); |
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162 | pixman_image_set_repeat (gradient, PIXMAN_REPEAT_PAD); |
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163 | |||
164 | image = pixman_image_create_bits (gradient_pixman_format, width, 1, |
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165 | bytes, sizeof(uint32_t)*width); |
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166 | if (unlikely (image == NULL)) { |
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167 | pixman_image_unref (gradient); |
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168 | return _cairo_error (CAIRO_STATUS_NO_MEMORY); |
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169 | } |
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170 | |||
171 | pixman_image_composite32 (PIXMAN_OP_SRC, |
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172 | gradient, NULL, image, |
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173 | 0, 0, |
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174 | 0, 0, |
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175 | 0, 0, |
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176 | width, 1); |
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177 | |||
178 | pixman_image_unref (gradient); |
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179 | pixman_image_unref (image); |
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180 | |||
181 | /* We need to fudge pixel 0 to hold the left-most color stop and not |
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182 | * the neareset stop to the zeroth pixel centre in order to correctly |
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183 | * populate the border color. For completeness, do both edges. |
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184 | */ |
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185 | ((uint32_t*)bytes)[0] = color_stop_to_pixel(&stops[0]); |
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186 | ((uint32_t*)bytes)[width-1] = color_stop_to_pixel(&stops[n_stops-1]); |
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187 | |||
188 | return CAIRO_STATUS_SUCCESS; |
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189 | } |
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190 | |||
191 | static unsigned long |
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192 | _cairo_gl_gradient_hash (unsigned int n_stops, |
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193 | const cairo_gradient_stop_t *stops) |
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194 | { |
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195 | return _cairo_hash_bytes (n_stops, |
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196 | stops, |
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197 | sizeof (cairo_gradient_stop_t) * n_stops); |
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198 | } |
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199 | |||
200 | static cairo_gl_gradient_t * |
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201 | _cairo_gl_gradient_lookup (cairo_gl_context_t *ctx, |
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202 | unsigned long hash, |
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203 | unsigned int n_stops, |
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204 | const cairo_gradient_stop_t *stops) |
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205 | { |
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206 | cairo_gl_gradient_t lookup; |
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207 | |||
208 | lookup.cache_entry.hash = hash, |
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209 | lookup.n_stops = n_stops; |
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210 | lookup.stops = stops; |
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211 | |||
212 | return _cairo_cache_lookup (&ctx->gradients, &lookup.cache_entry); |
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213 | } |
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214 | |||
215 | cairo_bool_t |
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216 | _cairo_gl_gradient_equal (const void *key_a, const void *key_b) |
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217 | { |
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218 | const cairo_gl_gradient_t *a = key_a; |
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219 | const cairo_gl_gradient_t *b = key_b; |
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220 | |||
221 | if (a->n_stops != b->n_stops) |
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222 | return FALSE; |
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223 | |||
224 | return memcmp (a->stops, b->stops, a->n_stops * sizeof (cairo_gradient_stop_t)) == 0; |
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225 | } |
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226 | |||
227 | cairo_int_status_t |
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228 | _cairo_gl_gradient_create (cairo_gl_context_t *ctx, |
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229 | unsigned int n_stops, |
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230 | const cairo_gradient_stop_t *stops, |
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231 | cairo_gl_gradient_t **gradient_out) |
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232 | { |
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233 | unsigned long hash; |
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234 | cairo_gl_gradient_t *gradient; |
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235 | cairo_status_t status; |
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236 | int tex_width; |
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237 | GLint internal_format; |
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238 | void *data; |
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239 | |||
240 | if ((unsigned int) ctx->max_texture_size / 2 <= n_stops) |
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241 | return CAIRO_INT_STATUS_UNSUPPORTED; |
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242 | |||
243 | hash = _cairo_gl_gradient_hash (n_stops, stops); |
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244 | |||
245 | gradient = _cairo_gl_gradient_lookup (ctx, hash, n_stops, stops); |
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246 | if (gradient) { |
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247 | *gradient_out = _cairo_gl_gradient_reference (gradient); |
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248 | return CAIRO_STATUS_SUCCESS; |
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249 | } |
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250 | |||
251 | gradient = malloc (sizeof (cairo_gl_gradient_t) + sizeof (cairo_gradient_stop_t) * (n_stops - 1)); |
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252 | if (gradient == NULL) |
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253 | return _cairo_error (CAIRO_STATUS_NO_MEMORY); |
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254 | |||
255 | tex_width = _cairo_gl_gradient_sample_width (n_stops, stops); |
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256 | if (tex_width > ctx->max_texture_size) |
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257 | tex_width = ctx->max_texture_size; |
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258 | |||
259 | CAIRO_REFERENCE_COUNT_INIT (&gradient->ref_count, 2); |
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260 | gradient->cache_entry.hash = hash; |
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261 | gradient->cache_entry.size = tex_width; |
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262 | gradient->device = &ctx->base; |
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263 | gradient->n_stops = n_stops; |
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264 | gradient->stops = gradient->stops_embedded; |
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265 | memcpy (gradient->stops_embedded, stops, n_stops * sizeof (cairo_gradient_stop_t)); |
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266 | |||
267 | glGenTextures (1, &gradient->tex); |
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268 | _cairo_gl_context_activate (ctx, CAIRO_GL_TEX_TEMP); |
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269 | glBindTexture (ctx->tex_target, gradient->tex); |
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270 | |||
271 | data = _cairo_malloc_ab (tex_width, sizeof (uint32_t)); |
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272 | if (unlikely (data == NULL)) { |
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273 | status = _cairo_error (CAIRO_STATUS_NO_MEMORY); |
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274 | goto cleanup_gradient; |
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275 | } |
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276 | |||
277 | status = _cairo_gl_gradient_render (ctx, n_stops, stops, data, tex_width); |
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278 | if (unlikely (status)) |
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279 | goto cleanup_data; |
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280 | |||
281 | /* |
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282 | * In OpenGL ES 2.0 no format conversion is allowed i.e. 'internalFormat' |
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283 | * must match 'format' in glTexImage2D. |
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284 | */ |
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285 | if (_cairo_gl_get_flavor () == CAIRO_GL_FLAVOR_ES) |
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286 | internal_format = GL_BGRA; |
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287 | else |
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288 | internal_format = GL_RGBA; |
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289 | |||
290 | glTexImage2D (ctx->tex_target, 0, internal_format, tex_width, 1, 0, |
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291 | GL_BGRA, GL_UNSIGNED_BYTE, data); |
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292 | |||
293 | free (data); |
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294 | |||
295 | /* we ignore errors here and just return an uncached gradient */ |
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296 | if (unlikely (_cairo_cache_insert (&ctx->gradients, &gradient->cache_entry))) |
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297 | CAIRO_REFERENCE_COUNT_INIT (&gradient->ref_count, 1); |
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298 | |||
299 | *gradient_out = gradient; |
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300 | return CAIRO_STATUS_SUCCESS; |
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301 | |||
302 | cleanup_data: |
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303 | free (data); |
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304 | cleanup_gradient: |
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305 | free (gradient); |
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306 | return status; |
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307 | } |
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308 | |||
309 | cairo_gl_gradient_t * |
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310 | _cairo_gl_gradient_reference (cairo_gl_gradient_t *gradient) |
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311 | { |
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312 | assert (CAIRO_REFERENCE_COUNT_HAS_REFERENCE (&gradient->ref_count)); |
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313 | |||
314 | _cairo_reference_count_inc (&gradient->ref_count); |
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315 | |||
316 | return gradient; |
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317 | } |
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318 | |||
319 | void |
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320 | _cairo_gl_gradient_destroy (cairo_gl_gradient_t *gradient) |
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321 | { |
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322 | cairo_gl_context_t *ctx; |
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323 | cairo_status_t ignore; |
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324 | |||
325 | assert (CAIRO_REFERENCE_COUNT_HAS_REFERENCE (&gradient->ref_count)); |
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326 | |||
327 | if (! _cairo_reference_count_dec_and_test (&gradient->ref_count)) |
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328 | return; |
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329 | |||
330 | if (_cairo_gl_context_acquire (gradient->device, &ctx) == CAIRO_STATUS_SUCCESS) { |
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331 | /* The gradient my still be active in the last operation, so flush */ |
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332 | _cairo_gl_composite_flush (ctx); |
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333 | glDeleteTextures (1, &gradient->tex); |
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334 | ignore = _cairo_gl_context_release (ctx, CAIRO_STATUS_SUCCESS); |
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335 | } |
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336 | |||
337 | free (gradient); |
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338 | }=>>><>><>><>><>><>><>><>><>> |