1 | /* |
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2 | * libcucul Canvas for ultrafast compositing of Unicode letters |
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3 | * Copyright (c) 2002-2006 Sam Hocevar <sam@zoy.org> |
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4 | * All Rights Reserved |
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5 | * |
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6 | * $Id: dither.c 1256 2006-10-29 08:35:46Z sam $ |
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7 | * |
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8 | * This library is free software; you can redistribute it and/or |
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9 | * modify it under the terms of the Do What The Fuck You Want To |
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10 | * Public License, Version 2, as published by Sam Hocevar. See |
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11 | * http://sam.zoy.org/wtfpl/COPYING for more details. |
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12 | */ |
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13 | |
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14 | /* |
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15 | * This file contains bitmap dithering functions. |
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16 | */ |
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17 | |
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18 | #include "config.h" |
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19 | #include "common.h" |
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20 | |
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21 | #if !defined(__KERNEL__) |
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22 | # if defined(HAVE_ENDIAN_H) |
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23 | # include <endian.h> |
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24 | # endif |
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25 | # include <stdio.h> |
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26 | # include <stdlib.h> |
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27 | # include <limits.h> |
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28 | # include <string.h> |
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29 | # if defined(HAVE_ERRNO_H) |
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30 | # include <errno.h> |
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31 | # endif |
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32 | #endif |
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33 | |
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34 | #include "cucul.h" |
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35 | #include "cucul_internals.h" |
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36 | |
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37 | #define CP437 0 |
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38 | |
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39 | /* |
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40 | * Local variables |
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41 | */ |
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42 | #if !defined(_DOXYGEN_SKIP_ME) |
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43 | # define LOOKUP_VAL 32 |
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44 | # define LOOKUP_SAT 32 |
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45 | # define LOOKUP_HUE 16 |
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46 | #endif |
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47 | static unsigned char hsv_distances[LOOKUP_VAL][LOOKUP_SAT][LOOKUP_HUE]; |
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48 | static uint16_t lookup_colors[8]; |
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49 | |
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50 | static int const hsv_palette[] = |
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51 | { |
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52 | /* weight, hue, saturation, value */ |
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53 | 4, 0x0, 0x0, 0x0, /* black */ |
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54 | 5, 0x0, 0x0, 0x5ff, /* 30% */ |
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55 | 5, 0x0, 0x0, 0x9ff, /* 70% */ |
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56 | 4, 0x0, 0x0, 0xfff, /* white */ |
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57 | 3, 0x1000, 0xfff, 0x5ff, /* dark yellow */ |
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58 | 2, 0x1000, 0xfff, 0xfff, /* light yellow */ |
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59 | 3, 0x0, 0xfff, 0x5ff, /* dark red */ |
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60 | 2, 0x0, 0xfff, 0xfff /* light red */ |
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61 | }; |
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62 | |
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63 | /* RGB palette for the new colour picker */ |
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64 | static int const rgb_palette[] = |
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65 | { |
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66 | 0x0, 0x0, 0x0, |
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67 | 0x0, 0x0, 0x7ff, |
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68 | 0x0, 0x7ff, 0x0, |
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69 | 0x0, 0x7ff, 0x7ff, |
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70 | 0x7ff, 0x0, 0x0, |
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71 | 0x7ff, 0x0, 0x7ff, |
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72 | 0x7ff, 0x7ff, 0x0, |
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73 | 0xaaa, 0xaaa, 0xaaa, |
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74 | 0x555, 0x555, 0x555, |
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75 | 0x000, 0x000, 0xfff, |
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76 | 0x000, 0xfff, 0x000, |
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77 | 0x000, 0xfff, 0xfff, |
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78 | 0xfff, 0x000, 0x000, |
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79 | 0xfff, 0x000, 0xfff, |
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80 | 0xfff, 0xfff, 0x000, |
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81 | 0xfff, 0xfff, 0xfff, |
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82 | }; |
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83 | |
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84 | static int const rgb_weight[] = |
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85 | { |
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86 | /* 2, 1, 1, 1, 1, 1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 2 */ |
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87 | 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 |
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88 | }; |
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89 | |
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90 | /* List of glyphs */ |
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91 | static uint32_t ascii_glyphs[] = |
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92 | { |
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93 | ' ', '.', ':', ';', 't', '%', 'S', 'X', '@', '8', '?' |
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94 | }; |
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95 | |
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96 | static uint32_t shades_glyphs[] = |
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97 | { |
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98 | /* ' '. '·', '░', '▒', '?' */ |
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99 | ' ', 0xb7, 0x2591, 0x2592, '?' |
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100 | }; |
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101 | |
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102 | static uint32_t blocks_glyphs[] = |
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103 | { |
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104 | /* ' ', '▘', '▚', '?' */ |
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105 | ' ', 0x2598, 0x259a, '?' |
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106 | }; |
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107 | |
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108 | #if !defined(_DOXYGEN_SKIP_ME) |
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109 | enum color_mode |
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110 | { |
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111 | COLOR_MODE_MONO, |
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112 | COLOR_MODE_GRAY, |
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113 | COLOR_MODE_8, |
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114 | COLOR_MODE_16, |
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115 | COLOR_MODE_FULLGRAY, |
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116 | COLOR_MODE_FULL8, |
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117 | COLOR_MODE_FULL16 |
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118 | }; |
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119 | |
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120 | struct cucul_dither |
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121 | { |
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122 | int bpp, has_palette, has_alpha; |
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123 | int w, h, pitch; |
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124 | int rmask, gmask, bmask, amask; |
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125 | int rright, gright, bright, aright; |
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126 | int rleft, gleft, bleft, aleft; |
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127 | void (*get_hsv)(cucul_dither_t *, char *, int, int); |
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128 | int red[256], green[256], blue[256], alpha[256]; |
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129 | float gamma; |
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130 | int gammatab[4097]; |
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131 | |
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132 | /* Bitmap features */ |
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133 | int invert, antialias; |
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134 | |
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135 | /* Colour mode used for rendering */ |
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136 | enum color_mode color_mode; |
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137 | |
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138 | /* Glyphs used for rendering */ |
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139 | uint32_t const * glyphs; |
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140 | unsigned glyph_count; |
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141 | |
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142 | /* Current dithering method */ |
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143 | void (*init_dither) (int); |
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144 | unsigned int (*get_dither) (void); |
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145 | void (*increment_dither) (void); |
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146 | }; |
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147 | |
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148 | #define HSV_XRATIO 6 |
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149 | #define HSV_YRATIO 3 |
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150 | #define HSV_HRATIO 3 |
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151 | |
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152 | #define HSV_DISTANCE(h, s, v, index) \ |
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153 | (hsv_palette[index * 4] \ |
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154 | * ((HSV_XRATIO * ((v) - hsv_palette[index * 4 + 3]) \ |
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155 | * ((v) - hsv_palette[index * 4 + 3])) \ |
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156 | + (hsv_palette[index * 4 + 3] \ |
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157 | ? (HSV_YRATIO * ((s) - hsv_palette[index * 4 + 2]) \ |
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158 | * ((s) - hsv_palette[index * 4 + 2])) \ |
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159 | : 0) \ |
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160 | + (hsv_palette[index * 4 + 2] \ |
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161 | ? (HSV_HRATIO * ((h) - hsv_palette[index * 4 + 1]) \ |
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162 | * ((h) - hsv_palette[index * 4 + 1])) \ |
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163 | : 0))) |
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164 | #endif |
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165 | |
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166 | /* |
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167 | * Local prototypes |
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168 | */ |
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169 | static void mask2shift(unsigned long int, int *, int *); |
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170 | static float gammapow(float x, float y); |
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171 | |
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172 | static void get_rgba_default(cucul_dither_t const *, uint8_t *, int, int, |
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173 | unsigned int *); |
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174 | |
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175 | /* Dithering methods */ |
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176 | static void init_no_dither(int); |
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177 | static unsigned int get_no_dither(void); |
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178 | static void increment_no_dither(void); |
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179 | |
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180 | static void init_fstein_dither(int); |
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181 | static unsigned int get_fstein_dither(void); |
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182 | static void increment_fstein_dither(void); |
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183 | |
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184 | static void init_ordered2_dither(int); |
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185 | static unsigned int get_ordered2_dither(void); |
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186 | static void increment_ordered2_dither(void); |
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187 | |
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188 | static void init_ordered4_dither(int); |
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189 | static unsigned int get_ordered4_dither(void); |
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190 | static void increment_ordered4_dither(void); |
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191 | |
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192 | static void init_ordered8_dither(int); |
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193 | static unsigned int get_ordered8_dither(void); |
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194 | static void increment_ordered8_dither(void); |
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195 | |
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196 | static void init_random_dither(int); |
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197 | static unsigned int get_random_dither(void); |
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198 | static void increment_random_dither(void); |
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199 | |
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200 | static inline int sq(int x) |
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201 | { |
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202 | return x * x; |
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203 | } |
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204 | |
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205 | static inline void rgb2hsv_default(int r, int g, int b, |
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206 | int *hue, int *sat, int *val) |
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207 | { |
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208 | int min, max, delta; |
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209 | |
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210 | min = r; max = r; |
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211 | if(min > g) min = g; if(max < g) max = g; |
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212 | if(min > b) min = b; if(max < b) max = b; |
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213 | |
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214 | delta = max - min; /* 0 - 0xfff */ |
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215 | *val = max; /* 0 - 0xfff */ |
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216 | |
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217 | if(delta) |
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218 | { |
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219 | *sat = 0xfff * delta / max; /* 0 - 0xfff */ |
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220 | |
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221 | /* Generate *hue between 0 and 0x5fff */ |
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222 | if( r == max ) |
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223 | *hue = 0x1000 + 0x1000 * (g - b) / delta; |
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224 | else if( g == max ) |
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225 | *hue = 0x3000 + 0x1000 * (b - r) / delta; |
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226 | else |
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227 | *hue = 0x5000 + 0x1000 * (r - g) / delta; |
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228 | } |
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229 | else |
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230 | { |
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231 | *sat = 0; |
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232 | *hue = 0; |
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233 | } |
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234 | } |
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235 | |
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236 | /** \brief Create an internal dither object. |
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237 | * |
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238 | * Create a dither structure from its coordinates (depth, width, height and |
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239 | * pitch) and pixel mask values. If the depth is 8 bits per pixel, the mask |
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240 | * values are ignored and the colour palette should be set using the |
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241 | * cucul_set_dither_palette() function. For depths greater than 8 bits per |
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242 | * pixel, a zero alpha mask causes the alpha values to be ignored. |
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243 | * |
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244 | * If an error occurs, NULL is returned and \b errno is set accordingly: |
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245 | * - \c EINVAL Requested width, height, pitch or bits per pixel value was |
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246 | * invalid. |
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247 | * - \c ENOMEM Not enough memory to allocate dither structure. |
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248 | * |
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249 | * \param bpp Bitmap depth in bits per pixel. |
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250 | * \param w Bitmap width in pixels. |
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251 | * \param h Bitmap height in pixels. |
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252 | * \param pitch Bitmap pitch in bytes. |
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253 | * \param rmask Bitmask for red values. |
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254 | * \param gmask Bitmask for green values. |
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255 | * \param bmask Bitmask for blue values. |
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256 | * \param amask Bitmask for alpha values. |
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257 | * \return Dither object upon success, NULL if an error occurred. |
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258 | */ |
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259 | cucul_dither_t *cucul_create_dither(unsigned int bpp, unsigned int w, |
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260 | unsigned int h, unsigned int pitch, |
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261 | unsigned long int rmask, |
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262 | unsigned long int gmask, |
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263 | unsigned long int bmask, |
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264 | unsigned long int amask) |
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265 | { |
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266 | cucul_dither_t *d; |
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267 | int i; |
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268 | |
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269 | /* Minor sanity test */ |
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270 | if(!w || !h || !pitch || bpp > 32 || bpp < 8) |
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271 | { |
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272 | #if defined(HAVE_ERRNO_H) |
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273 | errno = EINVAL; |
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274 | #endif |
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275 | return NULL; |
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276 | } |
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277 | |
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278 | d = malloc(sizeof(cucul_dither_t)); |
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279 | if(!d) |
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280 | { |
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281 | #if defined(HAVE_ERRNO_H) |
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282 | errno = ENOMEM; |
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283 | #endif |
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284 | return NULL; |
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285 | } |
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286 | |
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287 | d->bpp = bpp; |
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288 | d->has_palette = 0; |
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289 | d->has_alpha = amask ? 1 : 0; |
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290 | |
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291 | d->w = w; |
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292 | d->h = h; |
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293 | d->pitch = pitch; |
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294 | |
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295 | d->rmask = rmask; |
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296 | d->gmask = gmask; |
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297 | d->bmask = bmask; |
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298 | d->amask = amask; |
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299 | |
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300 | /* Load bitmasks */ |
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301 | if(rmask || gmask || bmask || amask) |
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302 | { |
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303 | mask2shift(rmask, &d->rright, &d->rleft); |
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304 | mask2shift(gmask, &d->gright, &d->gleft); |
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305 | mask2shift(bmask, &d->bright, &d->bleft); |
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306 | mask2shift(amask, &d->aright, &d->aleft); |
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307 | } |
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308 | |
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309 | /* In 8 bpp mode, default to a grayscale palette */ |
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310 | if(bpp == 8) |
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311 | { |
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312 | d->has_palette = 1; |
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313 | d->has_alpha = 0; |
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314 | for(i = 0; i < 256; i++) |
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315 | { |
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316 | d->red[i] = i * 0xfff / 256; |
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317 | d->green[i] = i * 0xfff / 256; |
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318 | d->blue[i] = i * 0xfff / 256; |
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319 | } |
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320 | } |
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321 | |
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322 | /* Default features */ |
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323 | d->invert = 0; |
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324 | d->antialias = 1; |
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325 | |
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326 | /* Default gamma value */ |
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327 | for(i = 0; i < 4096; i++) |
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328 | d->gammatab[i] = i; |
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329 | |
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330 | /* Default colour mode */ |
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331 | d->color_mode = COLOR_MODE_FULL16; |
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332 | |
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333 | /* Default character set */ |
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334 | d->glyphs = ascii_glyphs; |
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335 | d->glyph_count = sizeof(ascii_glyphs) / sizeof(*ascii_glyphs); |
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336 | |
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337 | /* Default dithering mode */ |
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338 | d->init_dither = init_fstein_dither; |
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339 | d->get_dither = get_fstein_dither; |
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340 | d->increment_dither = increment_fstein_dither; |
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341 | |
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342 | return d; |
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343 | } |
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344 | |
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345 | /** \brief Set the palette of an 8bpp dither object. |
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346 | * |
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347 | * Set the palette of an 8 bits per pixel bitmap. Values should be between |
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348 | * 0 and 4095 (0xfff). |
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349 | * |
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350 | * If an error occurs, -1 is returned and \b errno is set accordingly: |
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351 | * - \c EINVAL Dither bits per pixel value is not 8, or one of the pixel |
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352 | * values was outside the range 0 - 4095. |
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353 | * |
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354 | * \param d Dither object. |
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355 | * \param red Array of 256 red values. |
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356 | * \param green Array of 256 green values. |
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357 | * \param blue Array of 256 blue values. |
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358 | * \param alpha Array of 256 alpha values. |
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359 | * \return 0 in case of success, -1 if an error occurred. |
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360 | */ |
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361 | int cucul_set_dither_palette(cucul_dither_t *d, |
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362 | unsigned int red[], unsigned int green[], |
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363 | unsigned int blue[], unsigned int alpha[]) |
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364 | { |
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365 | int i, has_alpha = 0; |
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366 | |
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367 | if(d->bpp != 8) |
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368 | { |
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369 | #if defined(HAVE_ERRNO_H) |
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370 | errno = EINVAL; |
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371 | #endif |
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372 | return -1; |
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373 | } |
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374 | |
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375 | for(i = 0; i < 256; i++) |
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376 | { |
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377 | if((red[i] | green[i] | blue[i] | alpha[i]) >= 0x1000) |
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378 | { |
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379 | #if defined(HAVE_ERRNO_H) |
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380 | errno = EINVAL; |
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381 | #endif |
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382 | return -1; |
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383 | } |
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384 | } |
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385 | |
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386 | for(i = 0; i < 256; i++) |
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387 | { |
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388 | d->red[i] = red[i]; |
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389 | d->green[i] = green[i]; |
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390 | d->blue[i] = blue[i]; |
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391 | if(alpha[i]) |
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392 | { |
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393 | d->alpha[i] = alpha[i]; |
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394 | has_alpha = 1; |
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395 | } |
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396 | } |
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397 | |
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398 | d->has_alpha = has_alpha; |
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399 | |
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400 | return 0; |
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401 | } |
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402 | |
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403 | /** \brief Set the brightness of a dither object. |
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404 | * |
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405 | * Set the brightness of dither. |
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406 | * |
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407 | * If an error occurs, -1 is returned and \b errno is set accordingly: |
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408 | * - \c EINVAL Brightness value was out of range. |
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409 | * |
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410 | * \param d Dither object. |
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411 | * \param brightness brightness value. |
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412 | * \return 0 in case of success, -1 if an error occurred. |
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413 | */ |
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414 | int cucul_set_dither_brightness(cucul_dither_t *d, float brightness) |
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415 | { |
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416 | /* FIXME */ |
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417 | return 0; |
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418 | } |
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419 | |
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420 | /** \brief Set the gamma of a dither object. |
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421 | * |
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422 | * Set the gamma of dither. |
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423 | * |
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424 | * If an error occurs, -1 is returned and \b errno is set accordingly: |
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425 | * - \c EINVAL Gamma value was out of range. |
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426 | * |
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427 | * \param d Dither object. |
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428 | * \param gamma Gamma value. |
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429 | * \return 0 in case of success, -1 if an error occurred. |
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430 | */ |
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431 | int cucul_set_dither_gamma(cucul_dither_t *d, float gamma) |
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432 | { |
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433 | /* FIXME: we don't need 4096 calls to gammapow(), we could just compute |
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434 | * 128 of them and do linear interpolation for the rest. This will |
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435 | * probably speed up things a lot. */ |
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436 | int i; |
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437 | |
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438 | if(gamma <= 0.0) |
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439 | { |
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440 | #if defined(HAVE_ERRNO_H) |
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441 | errno = EINVAL; |
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442 | #endif |
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443 | return -1; |
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444 | } |
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445 | |
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446 | d->gamma = gamma; |
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447 | |
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448 | for(i = 0; i < 4096; i++) |
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449 | d->gammatab[i] = 4096.0 * gammapow((float)i / 4096.0, 1.0 / gamma); |
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450 | |
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451 | return 0; |
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452 | } |
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453 | |
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454 | /** \brief Invert colors of dither |
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455 | * |
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456 | * Invert colors of dither. |
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457 | * |
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458 | * This function never fails. |
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459 | * |
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460 | * \param d Dither object. |
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461 | * \param value 0 for normal behaviour, 1 for invert |
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462 | * \return This function always returns 0. |
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463 | */ |
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464 | int cucul_set_dither_invert(cucul_dither_t *d, int value) |
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465 | { |
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466 | d->invert = value ? 1 : 0; |
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467 | |
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468 | return 0; |
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469 | } |
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470 | |
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471 | /** \brief Set the contrast of a dither object. |
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472 | * |
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473 | * Set the contrast of dither. |
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474 | * |
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475 | * If an error occurs, -1 is returned and \b errno is set accordingly: |
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476 | * - \c EINVAL Contrast value was out of range. |
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477 | * |
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478 | * \param d Dither object. |
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479 | * \param contrast contrast value. |
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480 | * \return 0 in case of success, -1 if an error occurred. |
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481 | */ |
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482 | int cucul_set_dither_contrast(cucul_dither_t *d, float contrast) |
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483 | { |
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484 | /* FIXME */ |
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485 | return 0; |
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486 | } |
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487 | |
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488 | /** \brief Set dither antialiasing |
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489 | * |
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490 | * Tell the renderer whether to antialias the dither. Antialiasing smoothens |
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491 | * the rendered image and avoids the commonly seen staircase effect. |
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492 | * - \c "none": no antialiasing. |
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493 | * - \c "prefilter" or \c "default": simple prefilter antialiasing. This |
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494 | * is the default value. |
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495 | * |
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496 | * If an error occurs, -1 is returned and \b errno is set accordingly: |
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497 | * - \c EINVAL Invalid antialiasing mode. |
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498 | * |
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499 | * \param d Dither object. |
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500 | * \param str A string describing the antialiasing method that will be used |
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501 | * for the dithering. |
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502 | * \return 0 in case of success, -1 if an error occurred. |
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503 | */ |
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504 | int cucul_set_dither_antialias(cucul_dither_t *d, char const *str) |
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505 | { |
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506 | if(!strcasecmp(str, "none")) |
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507 | d->antialias = 0; |
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508 | else if(!strcasecmp(str, "prefilter") || !strcasecmp(str, "default")) |
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509 | d->antialias = 1; |
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510 | else |
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511 | { |
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512 | #if defined(HAVE_ERRNO_H) |
---|
513 | errno = EINVAL; |
---|
514 | #endif |
---|
515 | return -1; |
---|
516 | } |
---|
517 | |
---|
518 | return 0; |
---|
519 | } |
---|
520 | |
---|
521 | /** \brief Get available antialiasing methods |
---|
522 | * |
---|
523 | * Return a list of available antialiasing methods for a given dither. The |
---|
524 | * list is a NULL-terminated array of strings, interleaving a string |
---|
525 | * containing the internal value for the antialiasing method to be used with |
---|
526 | * cucul_set_dither_antialias(), and a string containing the natural |
---|
527 | * language description for that antialiasing method. |
---|
528 | * |
---|
529 | * This function never fails. |
---|
530 | * |
---|
531 | * \param d Dither object. |
---|
532 | * \return An array of strings. |
---|
533 | */ |
---|
534 | char const * const * |
---|
535 | cucul_get_dither_antialias_list(cucul_dither_t const *d) |
---|
536 | { |
---|
537 | static char const * const list[] = |
---|
538 | { |
---|
539 | "none", "No antialiasing", |
---|
540 | "prefilter", "Prefilter antialiasing", |
---|
541 | NULL, NULL |
---|
542 | }; |
---|
543 | |
---|
544 | return list; |
---|
545 | } |
---|
546 | |
---|
547 | /** \brief Choose colours used for dithering |
---|
548 | * |
---|
549 | * Tell the renderer which colours should be used to render the |
---|
550 | * bitmap. Valid values for \c str are: |
---|
551 | * - \c "mono": use light gray on a black background. |
---|
552 | * - \c "gray": use white and two shades of gray on a black background. |
---|
553 | * - \c "8": use the 8 ANSI colours on a black background. |
---|
554 | * - \c "16": use the 16 ANSI colours on a black background. |
---|
555 | * - \c "fullgray": use black, white and two shades of gray for both the |
---|
556 | * characters and the background. |
---|
557 | * - \c "full8": use the 8 ANSI colours for both the characters and the |
---|
558 | * background. |
---|
559 | * - \c "full16" or \c "default": use the 16 ANSI colours for both the |
---|
560 | * characters and the background. This is the default value. |
---|
561 | * |
---|
562 | * If an error occurs, -1 is returned and \b errno is set accordingly: |
---|
563 | * - \c EINVAL Invalid colour set. |
---|
564 | * |
---|
565 | * \param d Dither object. |
---|
566 | * \param str A string describing the colour set that will be used |
---|
567 | * for the dithering. |
---|
568 | * \return 0 in case of success, -1 if an error occurred. |
---|
569 | */ |
---|
570 | int cucul_set_dither_color(cucul_dither_t *d, char const *str) |
---|
571 | { |
---|
572 | if(!strcasecmp(str, "mono")) |
---|
573 | d->color_mode = COLOR_MODE_MONO; |
---|
574 | else if(!strcasecmp(str, "gray")) |
---|
575 | d->color_mode = COLOR_MODE_GRAY; |
---|
576 | else if(!strcasecmp(str, "8")) |
---|
577 | d->color_mode = COLOR_MODE_8; |
---|
578 | else if(!strcasecmp(str, "16")) |
---|
579 | d->color_mode = COLOR_MODE_16; |
---|
580 | else if(!strcasecmp(str, "fullgray")) |
---|
581 | d->color_mode = COLOR_MODE_FULLGRAY; |
---|
582 | else if(!strcasecmp(str, "full8")) |
---|
583 | d->color_mode = COLOR_MODE_FULL8; |
---|
584 | else if(!strcasecmp(str, "full16") || !strcasecmp(str, "default")) |
---|
585 | d->color_mode = COLOR_MODE_FULL16; |
---|
586 | else |
---|
587 | { |
---|
588 | #if defined(HAVE_ERRNO_H) |
---|
589 | errno = EINVAL; |
---|
590 | #endif |
---|
591 | return -1; |
---|
592 | } |
---|
593 | |
---|
594 | return 0; |
---|
595 | } |
---|
596 | |
---|
597 | /** \brief Get available colour modes |
---|
598 | * |
---|
599 | * Return a list of available colour modes for a given dither. The list |
---|
600 | * is a NULL-terminated array of strings, interleaving a string containing |
---|
601 | * the internal value for the colour mode, to be used with |
---|
602 | * cucul_set_dither_color(), and a string containing the natural |
---|
603 | * language description for that colour mode. |
---|
604 | * |
---|
605 | * This function never fails. |
---|
606 | * |
---|
607 | * \param d Dither object. |
---|
608 | * \return An array of strings. |
---|
609 | */ |
---|
610 | char const * const * |
---|
611 | cucul_get_dither_color_list(cucul_dither_t const *d) |
---|
612 | { |
---|
613 | static char const * const list[] = |
---|
614 | { |
---|
615 | "mono", "white on black", |
---|
616 | "gray", "grayscale on black", |
---|
617 | "8", "8 colours on black", |
---|
618 | "16", "16 colours on black", |
---|
619 | "fullgray", "full grayscale", |
---|
620 | "full8", "full 8 colours", |
---|
621 | "full16", "full 16 colours", |
---|
622 | NULL, NULL |
---|
623 | }; |
---|
624 | |
---|
625 | return list; |
---|
626 | } |
---|
627 | |
---|
628 | /** \brief Choose characters used for dithering |
---|
629 | * |
---|
630 | * Tell the renderer which characters should be used to render the |
---|
631 | * dither. Valid values for \c str are: |
---|
632 | * - \c "ascii" or \c "default": use only ASCII characters. This is the |
---|
633 | * default value. |
---|
634 | * - \c "shades": use Unicode characters "U+2591 LIGHT SHADE", "U+2592 |
---|
635 | * MEDIUM SHADE" and "U+2593 DARK SHADE". These characters are also |
---|
636 | * present in the CP437 codepage available on DOS and VGA. |
---|
637 | * - \c "blocks": use Unicode quarter-cell block combinations. These |
---|
638 | * characters are only found in the Unicode set. |
---|
639 | * |
---|
640 | * If an error occurs, -1 is returned and \b errno is set accordingly: |
---|
641 | * - \c EINVAL Invalid character set. |
---|
642 | * |
---|
643 | * \param d Dither object. |
---|
644 | * \param str A string describing the characters that need to be used |
---|
645 | * for the dithering. |
---|
646 | * \return 0 in case of success, -1 if an error occurred. |
---|
647 | */ |
---|
648 | int cucul_set_dither_charset(cucul_dither_t *d, char const *str) |
---|
649 | { |
---|
650 | if(!strcasecmp(str, "shades")) |
---|
651 | { |
---|
652 | d->glyphs = shades_glyphs; |
---|
653 | d->glyph_count = sizeof(shades_glyphs) / sizeof(*shades_glyphs); |
---|
654 | } |
---|
655 | else if(!strcasecmp(str, "blocks")) |
---|
656 | { |
---|
657 | d->glyphs = blocks_glyphs; |
---|
658 | d->glyph_count = sizeof(blocks_glyphs) / sizeof(*blocks_glyphs); |
---|
659 | } |
---|
660 | else if(!strcasecmp(str, "ascii") || !strcasecmp(str, "default")) |
---|
661 | { |
---|
662 | d->glyphs = ascii_glyphs; |
---|
663 | d->glyph_count = sizeof(ascii_glyphs) / sizeof(*ascii_glyphs); |
---|
664 | } |
---|
665 | else |
---|
666 | { |
---|
667 | #if defined(HAVE_ERRNO_H) |
---|
668 | errno = EINVAL; |
---|
669 | #endif |
---|
670 | return -1; |
---|
671 | } |
---|
672 | |
---|
673 | return 0; |
---|
674 | } |
---|
675 | |
---|
676 | /** \brief Get available dither character sets |
---|
677 | * |
---|
678 | * Return a list of available character sets for a given dither. The list |
---|
679 | * is a NULL-terminated array of strings, interleaving a string containing |
---|
680 | * the internal value for the character set, to be used with |
---|
681 | * cucul_set_dither_charset(), and a string containing the natural |
---|
682 | * language description for that character set. |
---|
683 | * |
---|
684 | * This function never fails. |
---|
685 | * |
---|
686 | * \param d Dither object. |
---|
687 | * \return An array of strings. |
---|
688 | */ |
---|
689 | char const * const * cucul_get_dither_charset_list(cucul_dither_t const *d) |
---|
690 | { |
---|
691 | static char const * const list[] = |
---|
692 | { |
---|
693 | "ascii", "plain ASCII", |
---|
694 | "shades", "CP437 shades", |
---|
695 | "blocks", "Unicode blocks", |
---|
696 | NULL, NULL |
---|
697 | }; |
---|
698 | |
---|
699 | return list; |
---|
700 | } |
---|
701 | |
---|
702 | /** \brief Set dithering method |
---|
703 | * |
---|
704 | * Tell the renderer which dithering method should be used. Dithering is |
---|
705 | * necessary because the picture being rendered has usually far more colours |
---|
706 | * than the available palette. Valid values for \c str are: |
---|
707 | * - \c "none": no dithering is used, the nearest matching colour is used. |
---|
708 | * - \c "ordered2": use a 2x2 Bayer matrix for dithering. |
---|
709 | * - \c "ordered4": use a 4x4 Bayer matrix for dithering. |
---|
710 | * - \c "ordered8": use a 8x8 Bayer matrix for dithering. |
---|
711 | * - \c "random": use random dithering. |
---|
712 | * - \c "fstein": use Floyd-Steinberg dithering. This is the default value. |
---|
713 | * |
---|
714 | * If an error occurs, -1 is returned and \b errno is set accordingly: |
---|
715 | * - \c EINVAL Unknown dithering mode. |
---|
716 | * |
---|
717 | * \param d Dither object. |
---|
718 | * \param str A string describing the method that needs to be used |
---|
719 | * for the dithering. |
---|
720 | * \return 0 in case of success, -1 if an error occurred. |
---|
721 | */ |
---|
722 | int cucul_set_dither_mode(cucul_dither_t *d, char const *str) |
---|
723 | { |
---|
724 | if(!strcasecmp(str, "none")) |
---|
725 | { |
---|
726 | d->init_dither = init_no_dither; |
---|
727 | d->get_dither = get_no_dither; |
---|
728 | d->increment_dither = increment_no_dither; |
---|
729 | } |
---|
730 | else if(!strcasecmp(str, "ordered2")) |
---|
731 | { |
---|
732 | d->init_dither = init_ordered2_dither; |
---|
733 | d->get_dither = get_ordered2_dither; |
---|
734 | d->increment_dither = increment_ordered2_dither; |
---|
735 | } |
---|
736 | else if(!strcasecmp(str, "ordered4")) |
---|
737 | { |
---|
738 | d->init_dither = init_ordered4_dither; |
---|
739 | d->get_dither = get_ordered4_dither; |
---|
740 | d->increment_dither = increment_ordered4_dither; |
---|
741 | } |
---|
742 | else if(!strcasecmp(str, "ordered8")) |
---|
743 | { |
---|
744 | d->init_dither = init_ordered8_dither; |
---|
745 | d->get_dither = get_ordered8_dither; |
---|
746 | d->increment_dither = increment_ordered8_dither; |
---|
747 | } |
---|
748 | else if(!strcasecmp(str, "random")) |
---|
749 | { |
---|
750 | d->init_dither = init_random_dither; |
---|
751 | d->get_dither = get_random_dither; |
---|
752 | d->increment_dither = increment_random_dither; |
---|
753 | } |
---|
754 | else if(!strcasecmp(str, "fstein") || !strcasecmp(str, "default")) |
---|
755 | { |
---|
756 | d->init_dither = init_fstein_dither; |
---|
757 | d->get_dither = get_fstein_dither; |
---|
758 | d->increment_dither = increment_fstein_dither; |
---|
759 | } |
---|
760 | else |
---|
761 | { |
---|
762 | #if defined(HAVE_ERRNO_H) |
---|
763 | errno = EINVAL; |
---|
764 | #endif |
---|
765 | return -1; |
---|
766 | } |
---|
767 | |
---|
768 | return 0; |
---|
769 | } |
---|
770 | |
---|
771 | /** \brief Get dithering methods |
---|
772 | * |
---|
773 | * Return a list of available dithering methods for a given dither. The list |
---|
774 | * is a NULL-terminated array of strings, interleaving a string containing |
---|
775 | * the internal value for the dithering method, to be used with |
---|
776 | * cucul_set_dither_dithering(), and a string containing the natural |
---|
777 | * language description for that dithering method. |
---|
778 | * |
---|
779 | * This function never fails. |
---|
780 | * |
---|
781 | * \param d Dither object. |
---|
782 | * \return An array of strings. |
---|
783 | */ |
---|
784 | char const * const * cucul_get_dither_mode_list(cucul_dither_t const *d) |
---|
785 | { |
---|
786 | static char const * const list[] = |
---|
787 | { |
---|
788 | "none", "no dithering", |
---|
789 | "ordered2", "2x2 ordered dithering", |
---|
790 | "ordered4", "4x4 ordered dithering", |
---|
791 | "ordered8", "8x8 ordered dithering", |
---|
792 | "random", "random dithering", |
---|
793 | "fstein", "Floyd-Steinberg dithering", |
---|
794 | NULL, NULL |
---|
795 | }; |
---|
796 | |
---|
797 | return list; |
---|
798 | } |
---|
799 | |
---|
800 | /** \brief Dither a bitmap on the canvas. |
---|
801 | * |
---|
802 | * Dither a bitmap at the given coordinates. The dither can be of any size |
---|
803 | * and will be stretched to the text area. |
---|
804 | * |
---|
805 | * This function never fails. |
---|
806 | * |
---|
807 | * \param cv A handle to the libcucul canvas. |
---|
808 | * \param x X coordinate of the upper-left corner of the drawing area. |
---|
809 | * \param y Y coordinate of the upper-left corner of the drawing area. |
---|
810 | * \param w Width of the drawing area. |
---|
811 | * \param h Height of the drawing area. |
---|
812 | * \param d Dither object to be drawn. |
---|
813 | * \param pixels Bitmap's pixels. |
---|
814 | * \return This function always returns 0. |
---|
815 | */ |
---|
816 | int cucul_dither_bitmap(cucul_canvas_t *cv, int x, int y, int w, int h, |
---|
817 | cucul_dither_t const *d, void *pixels) |
---|
818 | { |
---|
819 | int *floyd_steinberg, *fs_r, *fs_g, *fs_b; |
---|
820 | int fs_length; |
---|
821 | int x1, y1, x2, y2, pitch, deltax, deltay; |
---|
822 | unsigned int dchmax; |
---|
823 | |
---|
824 | if(!d || !pixels) |
---|
825 | return 0; |
---|
826 | |
---|
827 | x1 = x; x2 = x + w - 1; |
---|
828 | y1 = y; y2 = y + h - 1; |
---|
829 | |
---|
830 | /* FIXME: do not overwrite arguments */ |
---|
831 | w = d->w; |
---|
832 | h = d->h; |
---|
833 | pitch = d->pitch; |
---|
834 | |
---|
835 | deltax = x2 - x1 + 1; |
---|
836 | deltay = y2 - y1 + 1; |
---|
837 | dchmax = d->glyph_count; |
---|
838 | |
---|
839 | fs_length = ((int)cv->width <= x2 ? (int)cv->width : x2) + 1; |
---|
840 | floyd_steinberg = malloc(3 * (fs_length + 2) * sizeof(int)); |
---|
841 | memset(floyd_steinberg, 0, 3 * (fs_length + 2) * sizeof(int)); |
---|
842 | fs_r = floyd_steinberg + 1; |
---|
843 | fs_g = fs_r + fs_length + 2; |
---|
844 | fs_b = fs_g + fs_length + 2; |
---|
845 | |
---|
846 | for(y = y1 > 0 ? y1 : 0; y <= y2 && y <= (int)cv->height; y++) |
---|
847 | { |
---|
848 | int remain_r = 0, remain_g = 0, remain_b = 0; |
---|
849 | |
---|
850 | for(x = x1 > 0 ? x1 : 0, d->init_dither(y); |
---|
851 | x <= x2 && x <= (int)cv->width; |
---|
852 | x++) |
---|
853 | { |
---|
854 | unsigned int i; |
---|
855 | int ch = 0, distmin; |
---|
856 | unsigned int rgba[4]; |
---|
857 | int fg_r = 0, fg_g = 0, fg_b = 0, bg_r, bg_g, bg_b; |
---|
858 | int fromx, fromy, tox, toy, myx, myy, dots, dist; |
---|
859 | int error[3]; |
---|
860 | |
---|
861 | unsigned int outfg = 0, outbg = 0; |
---|
862 | uint32_t outch; |
---|
863 | |
---|
864 | rgba[0] = rgba[1] = rgba[2] = rgba[3] = 0; |
---|
865 | |
---|
866 | /* First get RGB */ |
---|
867 | if(d->antialias) |
---|
868 | { |
---|
869 | fromx = (x - x1) * w / deltax; |
---|
870 | fromy = (y - y1) * h / deltay; |
---|
871 | tox = (x - x1 + 1) * w / deltax; |
---|
872 | toy = (y - y1 + 1) * h / deltay; |
---|
873 | |
---|
874 | /* We want at least one pixel */ |
---|
875 | if(tox == fromx) tox++; |
---|
876 | if(toy == fromy) toy++; |
---|
877 | |
---|
878 | dots = 0; |
---|
879 | |
---|
880 | for(myx = fromx; myx < tox; myx++) |
---|
881 | for(myy = fromy; myy < toy; myy++) |
---|
882 | { |
---|
883 | dots++; |
---|
884 | get_rgba_default(d, pixels, myx, myy, rgba); |
---|
885 | } |
---|
886 | |
---|
887 | /* Normalize */ |
---|
888 | rgba[0] /= dots; |
---|
889 | rgba[1] /= dots; |
---|
890 | rgba[2] /= dots; |
---|
891 | rgba[3] /= dots; |
---|
892 | } |
---|
893 | else |
---|
894 | { |
---|
895 | fromx = (x - x1) * w / deltax; |
---|
896 | fromy = (y - y1) * h / deltay; |
---|
897 | tox = (x - x1 + 1) * w / deltax; |
---|
898 | toy = (y - y1 + 1) * h / deltay; |
---|
899 | |
---|
900 | /* tox and toy can overflow the canvas, but they cannot overflow |
---|
901 | * when averaged with fromx and fromy because these are guaranteed |
---|
902 | * to be within the pixel boundaries. */ |
---|
903 | myx = (fromx + tox) / 2; |
---|
904 | myy = (fromy + toy) / 2; |
---|
905 | |
---|
906 | get_rgba_default(d, pixels, myx, myy, rgba); |
---|
907 | } |
---|
908 | |
---|
909 | if(d->has_alpha && rgba[3] < 0x800) |
---|
910 | { |
---|
911 | remain_r = remain_g = remain_b = 0; |
---|
912 | fs_r[x] = 0; |
---|
913 | fs_g[x] = 0; |
---|
914 | fs_b[x] = 0; |
---|
915 | continue; |
---|
916 | } |
---|
917 | |
---|
918 | /* XXX: OMG HAX */ |
---|
919 | if(d->init_dither == init_fstein_dither) |
---|
920 | { |
---|
921 | rgba[0] += remain_r; |
---|
922 | rgba[1] += remain_g; |
---|
923 | rgba[2] += remain_b; |
---|
924 | } |
---|
925 | else |
---|
926 | { |
---|
927 | rgba[0] += (d->get_dither() - 0x80) * 4; |
---|
928 | rgba[1] += (d->get_dither() - 0x80) * 4; |
---|
929 | rgba[2] += (d->get_dither() - 0x80) * 4; |
---|
930 | } |
---|
931 | |
---|
932 | distmin = INT_MAX; |
---|
933 | for(i = 0; i < 16; i++) |
---|
934 | { |
---|
935 | dist = sq(rgba[0] - rgb_palette[i * 3]) |
---|
936 | + sq(rgba[1] - rgb_palette[i * 3 + 1]) |
---|
937 | + sq(rgba[2] - rgb_palette[i * 3 + 2]); |
---|
938 | dist *= rgb_weight[i]; |
---|
939 | if(dist < distmin) |
---|
940 | { |
---|
941 | outbg = i; |
---|
942 | distmin = dist; |
---|
943 | } |
---|
944 | } |
---|
945 | bg_r = rgb_palette[outbg * 3]; |
---|
946 | bg_g = rgb_palette[outbg * 3 + 1]; |
---|
947 | bg_b = rgb_palette[outbg * 3 + 2]; |
---|
948 | |
---|
949 | /* FIXME: we currently only honour "full16" */ |
---|
950 | if(d->color_mode == COLOR_MODE_FULL16) |
---|
951 | { |
---|
952 | distmin = INT_MAX; |
---|
953 | for(i = 0; i < 16; i++) |
---|
954 | { |
---|
955 | if(i == outbg) |
---|
956 | continue; |
---|
957 | dist = sq(rgba[0] - rgb_palette[i * 3]) |
---|
958 | + sq(rgba[1] - rgb_palette[i * 3 + 1]) |
---|
959 | + sq(rgba[2] - rgb_palette[i * 3 + 2]); |
---|
960 | dist *= rgb_weight[i]; |
---|
961 | if(dist < distmin) |
---|
962 | { |
---|
963 | outfg = i; |
---|
964 | distmin = dist; |
---|
965 | } |
---|
966 | } |
---|
967 | fg_r = rgb_palette[outfg * 3]; |
---|
968 | fg_g = rgb_palette[outfg * 3 + 1]; |
---|
969 | fg_b = rgb_palette[outfg * 3 + 2]; |
---|
970 | |
---|
971 | distmin = INT_MAX; |
---|
972 | for(i = 0; i < dchmax - 1; i++) |
---|
973 | { |
---|
974 | int newr = i * fg_r + ((2*dchmax-1) - i) * bg_r; |
---|
975 | int newg = i * fg_g + ((2*dchmax-1) - i) * bg_g; |
---|
976 | int newb = i * fg_b + ((2*dchmax-1) - i) * bg_b; |
---|
977 | dist = abs(rgba[0] * (2*dchmax-1) - newr) |
---|
978 | + abs(rgba[1] * (2*dchmax-1) - newg) |
---|
979 | + abs(rgba[2] * (2*dchmax-1) - newb); |
---|
980 | |
---|
981 | if(dist < distmin) |
---|
982 | { |
---|
983 | ch = i; |
---|
984 | distmin = dist; |
---|
985 | } |
---|
986 | } |
---|
987 | outch = d->glyphs[ch]; |
---|
988 | |
---|
989 | /* XXX: OMG HAX */ |
---|
990 | if(d->init_dither == init_fstein_dither) |
---|
991 | { |
---|
992 | error[0] = rgba[0] - (fg_r * ch + bg_r * ((2*dchmax-1) - ch)) / (2*dchmax-1); |
---|
993 | error[1] = rgba[1] - (fg_g * ch + bg_g * ((2*dchmax-1) - ch)) / (2*dchmax-1); |
---|
994 | error[2] = rgba[2] - (fg_b * ch + bg_b * ((2*dchmax-1) - ch)) / (2*dchmax-1); |
---|
995 | } |
---|
996 | } |
---|
997 | else |
---|
998 | { |
---|
999 | unsigned int lum = rgba[0]; |
---|
1000 | if(rgba[1] > lum) lum = rgba[1]; |
---|
1001 | if(rgba[2] > lum) lum = rgba[2]; |
---|
1002 | outfg = outbg; |
---|
1003 | outbg = CUCUL_COLOR_BLACK; |
---|
1004 | |
---|
1005 | ch = lum * dchmax / 0x1000; |
---|
1006 | if(ch < 0) |
---|
1007 | ch = 0; |
---|
1008 | else if(ch > (int)(dchmax - 1)) |
---|
1009 | ch = dchmax - 1; |
---|
1010 | outch = d->glyphs[ch]; |
---|
1011 | |
---|
1012 | /* XXX: OMG HAX */ |
---|
1013 | if(d->init_dither == init_fstein_dither) |
---|
1014 | { |
---|
1015 | error[0] = rgba[0] - bg_r * ch / (dchmax-1); |
---|
1016 | error[1] = rgba[1] - bg_g * ch / (dchmax-1); |
---|
1017 | error[2] = rgba[2] - bg_b * ch / (dchmax-1); |
---|
1018 | } |
---|
1019 | } |
---|
1020 | |
---|
1021 | /* XXX: OMG HAX */ |
---|
1022 | if(d->init_dither == init_fstein_dither) |
---|
1023 | { |
---|
1024 | remain_r = fs_r[x+1] + 7 * error[0] / 16; |
---|
1025 | remain_g = fs_g[x+1] + 7 * error[1] / 16; |
---|
1026 | remain_b = fs_b[x+1] + 7 * error[2] / 16; |
---|
1027 | fs_r[x-1] += 3 * error[0] / 16; |
---|
1028 | fs_g[x-1] += 3 * error[1] / 16; |
---|
1029 | fs_b[x-1] += 3 * error[2] / 16; |
---|
1030 | fs_r[x] = 5 * error[0] / 16; |
---|
1031 | fs_g[x] = 5 * error[1] / 16; |
---|
1032 | fs_b[x] = 5 * error[2] / 16; |
---|
1033 | fs_r[x+1] = 1 * error[0] / 16; |
---|
1034 | fs_g[x+1] = 1 * error[1] / 16; |
---|
1035 | fs_b[x+1] = 1 * error[2] / 16; |
---|
1036 | } |
---|
1037 | |
---|
1038 | if(d->invert) |
---|
1039 | { |
---|
1040 | outfg = 15 - outfg; |
---|
1041 | outbg = 15 - outbg; |
---|
1042 | } |
---|
1043 | |
---|
1044 | /* Now output the character */ |
---|
1045 | cucul_set_attr_ansi(cv, outfg, outbg, 0); |
---|
1046 | cucul_putchar(cv, x, y, outch); |
---|
1047 | |
---|
1048 | d->increment_dither(); |
---|
1049 | } |
---|
1050 | /* end loop */ |
---|
1051 | } |
---|
1052 | |
---|
1053 | free(floyd_steinberg); |
---|
1054 | |
---|
1055 | return 0; |
---|
1056 | } |
---|
1057 | |
---|
1058 | /** \brief Free the memory associated with a dither. |
---|
1059 | * |
---|
1060 | * Free the memory allocated by cucul_create_dither(). |
---|
1061 | * |
---|
1062 | * This function never fails. |
---|
1063 | * |
---|
1064 | * \param d Dither object. |
---|
1065 | * \return This function always returns 0. |
---|
1066 | */ |
---|
1067 | int cucul_free_dither(cucul_dither_t *d) |
---|
1068 | { |
---|
1069 | if(!d) |
---|
1070 | return 0; |
---|
1071 | |
---|
1072 | free(d); |
---|
1073 | |
---|
1074 | return 0; |
---|
1075 | } |
---|
1076 | |
---|
1077 | /* |
---|
1078 | * XXX: The following functions are local. |
---|
1079 | */ |
---|
1080 | |
---|
1081 | /* Convert a mask, eg. 0x0000ff00, to shift values, eg. 8 and -4. */ |
---|
1082 | static void mask2shift(unsigned long int mask, int *right, int *left) |
---|
1083 | { |
---|
1084 | int rshift = 0, lshift = 0; |
---|
1085 | |
---|
1086 | if(!mask) |
---|
1087 | { |
---|
1088 | *right = *left = 0; |
---|
1089 | return; |
---|
1090 | } |
---|
1091 | |
---|
1092 | while(!(mask & 1)) |
---|
1093 | { |
---|
1094 | mask >>= 1; |
---|
1095 | rshift++; |
---|
1096 | } |
---|
1097 | *right = rshift; |
---|
1098 | |
---|
1099 | while(mask & 1) |
---|
1100 | { |
---|
1101 | mask >>= 1; |
---|
1102 | lshift++; |
---|
1103 | } |
---|
1104 | *left = 12 - lshift; |
---|
1105 | } |
---|
1106 | |
---|
1107 | /* Compute x^y without relying on the math library */ |
---|
1108 | static float gammapow(float x, float y) |
---|
1109 | { |
---|
1110 | #ifdef HAVE_FLDLN2 |
---|
1111 | register double logx; |
---|
1112 | register long double v, e; |
---|
1113 | #else |
---|
1114 | register float tmp, t, t2, r; |
---|
1115 | int i; |
---|
1116 | #endif |
---|
1117 | |
---|
1118 | if(x == 0.0) |
---|
1119 | return y == 0.0 ? 1.0 : 0.0; |
---|
1120 | |
---|
1121 | #ifdef HAVE_FLDLN2 |
---|
1122 | /* FIXME: this can be optimised by directly calling fyl2x for x and y */ |
---|
1123 | asm volatile("fldln2; fxch; fyl2x" |
---|
1124 | : "=t" (logx) : "0" (x) : "st(1)"); |
---|
1125 | |
---|
1126 | asm volatile("fldl2e\n\t" |
---|
1127 | "fmul %%st(1)\n\t" |
---|
1128 | "fst %%st(1)\n\t" |
---|
1129 | "frndint\n\t" |
---|
1130 | "fxch\n\t" |
---|
1131 | "fsub %%st(1)\n\t" |
---|
1132 | "f2xm1\n\t" |
---|
1133 | : "=t" (v), "=u" (e) : "0" (y * logx)); |
---|
1134 | v += 1.0; |
---|
1135 | asm volatile("fscale" |
---|
1136 | : "=t" (v) : "0" (v), "u" (e)); |
---|
1137 | return v; |
---|
1138 | #else |
---|
1139 | /* Compute ln(x) for x ∈ ]0,1] |
---|
1140 | * ln(x) = 2 * (t + t^3/3 + t^5/5 + ...) with t = (x-1)/(x+1) |
---|
1141 | * The convergence is a bit slow, especially when x is near 0. */ |
---|
1142 | t = (x - 1.0) / (x + 1.0); |
---|
1143 | t2 = t * t; |
---|
1144 | tmp = r = t; |
---|
1145 | for(i = 3; i < 20; i += 2) |
---|
1146 | { |
---|
1147 | r *= t2; |
---|
1148 | tmp += r / i; |
---|
1149 | } |
---|
1150 | |
---|
1151 | /* Compute -y*ln(x) */ |
---|
1152 | tmp = - y * 2.0 * tmp; |
---|
1153 | |
---|
1154 | /* Compute x^-y as e^t where t = -y*ln(x): |
---|
1155 | * e^t = 1 + t/1! + t^2/2! + t^3/3! + t^4/4! + t^5/5! ... |
---|
1156 | * The convergence is quite faster here, thanks to the factorial. */ |
---|
1157 | r = t = tmp; |
---|
1158 | tmp = 1.0 + t; |
---|
1159 | for(i = 2; i < 16; i++) |
---|
1160 | { |
---|
1161 | r = r * t / i; |
---|
1162 | tmp += r; |
---|
1163 | } |
---|
1164 | |
---|
1165 | /* Return x^y as 1/(x^-y) */ |
---|
1166 | return 1.0 / tmp; |
---|
1167 | #endif |
---|
1168 | } |
---|
1169 | |
---|
1170 | static void get_rgba_default(cucul_dither_t const *d, uint8_t *pixels, |
---|
1171 | int x, int y, unsigned int *rgba) |
---|
1172 | { |
---|
1173 | uint32_t bits; |
---|
1174 | |
---|
1175 | pixels += (d->bpp / 8) * x + d->pitch * y; |
---|
1176 | |
---|
1177 | switch(d->bpp / 8) |
---|
1178 | { |
---|
1179 | case 4: |
---|
1180 | bits = *(uint32_t *)pixels; |
---|
1181 | break; |
---|
1182 | case 3: |
---|
1183 | { |
---|
1184 | #if defined(HAVE_ENDIAN_H) |
---|
1185 | if(__BYTE_ORDER == __BIG_ENDIAN) |
---|
1186 | #else |
---|
1187 | /* This is compile-time optimised with at least -O1 or -Os */ |
---|
1188 | uint32_t const tmp = 0x12345678; |
---|
1189 | if(*(uint8_t const *)&tmp == 0x12) |
---|
1190 | #endif |
---|
1191 | bits = ((uint32_t)pixels[0] << 16) | |
---|
1192 | ((uint32_t)pixels[1] << 8) | |
---|
1193 | ((uint32_t)pixels[2]); |
---|
1194 | else |
---|
1195 | bits = ((uint32_t)pixels[2] << 16) | |
---|
1196 | ((uint32_t)pixels[1] << 8) | |
---|
1197 | ((uint32_t)pixels[0]); |
---|
1198 | break; |
---|
1199 | } |
---|
1200 | case 2: |
---|
1201 | bits = *(uint16_t *)pixels; |
---|
1202 | break; |
---|
1203 | case 1: |
---|
1204 | default: |
---|
1205 | bits = pixels[0]; |
---|
1206 | break; |
---|
1207 | } |
---|
1208 | |
---|
1209 | if(d->has_palette) |
---|
1210 | { |
---|
1211 | rgba[0] += d->gammatab[d->red[bits]]; |
---|
1212 | rgba[1] += d->gammatab[d->green[bits]]; |
---|
1213 | rgba[2] += d->gammatab[d->blue[bits]]; |
---|
1214 | rgba[3] += d->alpha[bits]; |
---|
1215 | } |
---|
1216 | else |
---|
1217 | { |
---|
1218 | rgba[0] += d->gammatab[((bits & d->rmask) >> d->rright) << d->rleft]; |
---|
1219 | rgba[1] += d->gammatab[((bits & d->gmask) >> d->gright) << d->gleft]; |
---|
1220 | rgba[2] += d->gammatab[((bits & d->bmask) >> d->bright) << d->bleft]; |
---|
1221 | rgba[3] += ((bits & d->amask) >> d->aright) << d->aleft; |
---|
1222 | } |
---|
1223 | } |
---|
1224 | |
---|
1225 | /* |
---|
1226 | * No dithering |
---|
1227 | */ |
---|
1228 | static void init_no_dither(int line) |
---|
1229 | { |
---|
1230 | ; |
---|
1231 | } |
---|
1232 | |
---|
1233 | static unsigned int get_no_dither(void) |
---|
1234 | { |
---|
1235 | return 0x80; |
---|
1236 | } |
---|
1237 | |
---|
1238 | static void increment_no_dither(void) |
---|
1239 | { |
---|
1240 | return; |
---|
1241 | } |
---|
1242 | |
---|
1243 | /* |
---|
1244 | * Floyd-Steinberg dithering |
---|
1245 | */ |
---|
1246 | static void init_fstein_dither(int line) |
---|
1247 | { |
---|
1248 | ; |
---|
1249 | } |
---|
1250 | |
---|
1251 | static unsigned int get_fstein_dither(void) |
---|
1252 | { |
---|
1253 | return 0x80; |
---|
1254 | } |
---|
1255 | |
---|
1256 | static void increment_fstein_dither(void) |
---|
1257 | { |
---|
1258 | return; |
---|
1259 | } |
---|
1260 | |
---|
1261 | /* |
---|
1262 | * Ordered 2 dithering |
---|
1263 | */ |
---|
1264 | static unsigned int const *ordered2_table; |
---|
1265 | static unsigned int ordered2_index; |
---|
1266 | |
---|
1267 | static void init_ordered2_dither(int line) |
---|
1268 | { |
---|
1269 | static unsigned int const dither2x2[] = |
---|
1270 | { |
---|
1271 | 0x00, 0x80, |
---|
1272 | 0xc0, 0x40, |
---|
1273 | }; |
---|
1274 | |
---|
1275 | ordered2_table = dither2x2 + (line % 2) * 2; |
---|
1276 | ordered2_index = 0; |
---|
1277 | } |
---|
1278 | |
---|
1279 | static unsigned int get_ordered2_dither(void) |
---|
1280 | { |
---|
1281 | return ordered2_table[ordered2_index]; |
---|
1282 | } |
---|
1283 | |
---|
1284 | static void increment_ordered2_dither(void) |
---|
1285 | { |
---|
1286 | ordered2_index = (ordered2_index + 1) % 2; |
---|
1287 | } |
---|
1288 | |
---|
1289 | /* |
---|
1290 | * Ordered 4 dithering |
---|
1291 | */ |
---|
1292 | /*static int dither4x4[] = { 5, 0, 1, 6, |
---|
1293 | -1, -6, -5, 2, |
---|
1294 | -2, -7, -8, 3, |
---|
1295 | 4, -3, -4, -7};*/ |
---|
1296 | static unsigned int const *ordered4_table; |
---|
1297 | static unsigned int ordered4_index; |
---|
1298 | |
---|
1299 | static void init_ordered4_dither(int line) |
---|
1300 | { |
---|
1301 | static unsigned int const dither4x4[] = |
---|
1302 | { |
---|
1303 | 0x00, 0x80, 0x20, 0xa0, |
---|
1304 | 0xc0, 0x40, 0xe0, 0x60, |
---|
1305 | 0x30, 0xb0, 0x10, 0x90, |
---|
1306 | 0xf0, 0x70, 0xd0, 0x50 |
---|
1307 | }; |
---|
1308 | |
---|
1309 | ordered4_table = dither4x4 + (line % 4) * 4; |
---|
1310 | ordered4_index = 0; |
---|
1311 | } |
---|
1312 | |
---|
1313 | static unsigned int get_ordered4_dither(void) |
---|
1314 | { |
---|
1315 | return ordered4_table[ordered4_index]; |
---|
1316 | } |
---|
1317 | |
---|
1318 | static void increment_ordered4_dither(void) |
---|
1319 | { |
---|
1320 | ordered4_index = (ordered4_index + 1) % 4; |
---|
1321 | } |
---|
1322 | |
---|
1323 | /* |
---|
1324 | * Ordered 8 dithering |
---|
1325 | */ |
---|
1326 | static unsigned int const *ordered8_table; |
---|
1327 | static unsigned int ordered8_index; |
---|
1328 | |
---|
1329 | static void init_ordered8_dither(int line) |
---|
1330 | { |
---|
1331 | static unsigned int const dither8x8[] = |
---|
1332 | { |
---|
1333 | 0x00, 0x80, 0x20, 0xa0, 0x08, 0x88, 0x28, 0xa8, |
---|
1334 | 0xc0, 0x40, 0xe0, 0x60, 0xc8, 0x48, 0xe8, 0x68, |
---|
1335 | 0x30, 0xb0, 0x10, 0x90, 0x38, 0xb8, 0x18, 0x98, |
---|
1336 | 0xf0, 0x70, 0xd0, 0x50, 0xf8, 0x78, 0xd8, 0x58, |
---|
1337 | 0x0c, 0x8c, 0x2c, 0xac, 0x04, 0x84, 0x24, 0xa4, |
---|
1338 | 0xcc, 0x4c, 0xec, 0x6c, 0xc4, 0x44, 0xe4, 0x64, |
---|
1339 | 0x3c, 0xbc, 0x1c, 0x9c, 0x34, 0xb4, 0x14, 0x94, |
---|
1340 | 0xfc, 0x7c, 0xdc, 0x5c, 0xf4, 0x74, 0xd4, 0x54, |
---|
1341 | }; |
---|
1342 | |
---|
1343 | ordered8_table = dither8x8 + (line % 8) * 8; |
---|
1344 | ordered8_index = 0; |
---|
1345 | } |
---|
1346 | |
---|
1347 | static unsigned int get_ordered8_dither(void) |
---|
1348 | { |
---|
1349 | return ordered8_table[ordered8_index]; |
---|
1350 | } |
---|
1351 | |
---|
1352 | static void increment_ordered8_dither(void) |
---|
1353 | { |
---|
1354 | ordered8_index = (ordered8_index + 1) % 8; |
---|
1355 | } |
---|
1356 | |
---|
1357 | /* |
---|
1358 | * Random dithering |
---|
1359 | */ |
---|
1360 | static void init_random_dither(int line) |
---|
1361 | { |
---|
1362 | ; |
---|
1363 | } |
---|
1364 | |
---|
1365 | static unsigned int get_random_dither(void) |
---|
1366 | { |
---|
1367 | return cucul_rand(0x00, 0x100); |
---|
1368 | } |
---|
1369 | |
---|
1370 | static void increment_random_dither(void) |
---|
1371 | { |
---|
1372 | return; |
---|
1373 | } |
---|
1374 | |
---|
1375 | #if !defined(_DOXYGEN_SKIP_ME) |
---|
1376 | int _cucul_init_dither(void) |
---|
1377 | { |
---|
1378 | unsigned int v, s, h; |
---|
1379 | |
---|
1380 | /* These ones are constant */ |
---|
1381 | lookup_colors[0] = CUCUL_COLOR_BLACK; |
---|
1382 | lookup_colors[1] = CUCUL_COLOR_DARKGRAY; |
---|
1383 | lookup_colors[2] = CUCUL_COLOR_LIGHTGRAY; |
---|
1384 | lookup_colors[3] = CUCUL_COLOR_WHITE; |
---|
1385 | |
---|
1386 | /* These ones will be overwritten */ |
---|
1387 | lookup_colors[4] = CUCUL_COLOR_MAGENTA; |
---|
1388 | lookup_colors[5] = CUCUL_COLOR_LIGHTMAGENTA; |
---|
1389 | lookup_colors[6] = CUCUL_COLOR_RED; |
---|
1390 | lookup_colors[7] = CUCUL_COLOR_LIGHTRED; |
---|
1391 | |
---|
1392 | for(v = 0; v < LOOKUP_VAL; v++) |
---|
1393 | for(s = 0; s < LOOKUP_SAT; s++) |
---|
1394 | for(h = 0; h < LOOKUP_HUE; h++) |
---|
1395 | { |
---|
1396 | int i, distbg, distfg, dist; |
---|
1397 | int val, sat, hue; |
---|
1398 | unsigned char outbg, outfg; |
---|
1399 | |
---|
1400 | val = 0xfff * v / (LOOKUP_VAL - 1); |
---|
1401 | sat = 0xfff * s / (LOOKUP_SAT - 1); |
---|
1402 | hue = 0xfff * h / (LOOKUP_HUE - 1); |
---|
1403 | |
---|
1404 | /* Initialise distances to the distance between pure black HSV |
---|
1405 | * coordinates and our white colour (3) */ |
---|
1406 | outbg = outfg = 3; |
---|
1407 | distbg = distfg = HSV_DISTANCE(0, 0, 0, 3); |
---|
1408 | |
---|
1409 | /* Calculate distances to eight major colour values and store the |
---|
1410 | * two nearest points in our lookup table. */ |
---|
1411 | for(i = 0; i < 8; i++) |
---|
1412 | { |
---|
1413 | dist = HSV_DISTANCE(hue, sat, val, i); |
---|
1414 | if(dist <= distbg) |
---|
1415 | { |
---|
1416 | outfg = outbg; |
---|
1417 | distfg = distbg; |
---|
1418 | outbg = i; |
---|
1419 | distbg = dist; |
---|
1420 | } |
---|
1421 | else if(dist <= distfg) |
---|
1422 | { |
---|
1423 | outfg = i; |
---|
1424 | distfg = dist; |
---|
1425 | } |
---|
1426 | } |
---|
1427 | |
---|
1428 | hsv_distances[v][s][h] = (outfg << 4) | outbg; |
---|
1429 | } |
---|
1430 | |
---|
1431 | return 0; |
---|
1432 | } |
---|
1433 | |
---|
1434 | int _cucul_end_dither(void) |
---|
1435 | { |
---|
1436 | return 0; |
---|
1437 | } |
---|
1438 | #endif /* _DOXYGEN_SKIP_ME */ |
---|
1439 | |
---|
1440 | |
---|