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2 | pj | 1 | /* |
2 | * ordered.c -- |
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3 | * |
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4 | * This file contains C code to implement an ordered dither. |
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5 | * |
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6 | */ |
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7 | |||
8 | /* |
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9 | * Copyright (c) 1995 The Regents of the University of California. |
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10 | * All rights reserved. |
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11 | * |
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12 | * Permission to use, copy, modify, and distribute this software and its |
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13 | * documentation for any purpose, without fee, and without written agreement is |
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14 | * hereby granted, provided that the above copyright notice and the following |
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15 | * two paragraphs appear in all copies of this software. |
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16 | * |
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17 | * IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR |
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18 | * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT |
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19 | * OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF |
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20 | * CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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21 | * |
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22 | * THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES, |
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23 | * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY |
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24 | * AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS |
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25 | * ON AN "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATION TO |
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26 | * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS. |
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27 | */ |
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28 | |||
29 | #include "video.h" |
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30 | #include "proto.h" |
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31 | #include "dither.h" |
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32 | |||
33 | #define DITH_SIZE 16 |
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34 | |||
35 | |||
36 | /* Structures used to implement hybrid ordered dither/floyd-steinberg |
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37 | dither algorithm. |
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38 | */ |
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39 | |||
40 | static unsigned char *l_darrays[DITH_SIZE]; |
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41 | static unsigned char *cr_darrays[DITH_SIZE]; |
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42 | static unsigned char *cb_darrays[DITH_SIZE]; |
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43 | |||
44 | /* |
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45 | *-------------------------------------------------------------- |
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46 | * |
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47 | * InitOrderedDither-- |
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48 | * |
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49 | * Structures intialized for ordered dithering. |
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50 | * |
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51 | * Results: |
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52 | * None. |
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53 | * |
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54 | * Side effects: |
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55 | * None. |
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56 | * |
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57 | *-------------------------------------------------------------- |
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58 | */ |
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59 | |||
60 | void |
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61 | InitOrderedDither() |
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62 | { |
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63 | int i, j, k, err_range, threshval; |
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64 | unsigned char *lmark, *cmark; |
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65 | |||
66 | for (i=0; i<DITH_SIZE; i++) { |
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67 | lmark = l_darrays[i] = (unsigned char *) malloc(256); |
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68 | |||
69 | for (j=0; j<lum_values[0]; j++) { |
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70 | *lmark++ = 0; |
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71 | } |
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72 | |||
73 | for (j=0; j<(LUM_RANGE-1); j++) { |
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74 | err_range = lum_values[j+1] - lum_values[j]; |
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75 | threshval = ((i * err_range) / DITH_SIZE)+lum_values[j]; |
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76 | |||
77 | for (k=lum_values[j]; k<lum_values[j+1]; k++) { |
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78 | if (k > threshval) { |
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79 | *lmark++ = ((j+1) * (CR_RANGE * CB_RANGE)); |
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80 | } |
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81 | else { |
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82 | *lmark++ = (j * (CR_RANGE * CB_RANGE)); |
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83 | } |
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84 | } |
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85 | } |
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86 | |||
87 | for (j=lum_values[LUM_RANGE-1]; j<256; j++) { |
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88 | *lmark++ = (LUM_RANGE-1)*(CR_RANGE * CB_RANGE); |
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89 | } |
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90 | } |
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91 | |||
92 | for (i=0; i<DITH_SIZE; i++) { |
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93 | cmark = cr_darrays[i] = (unsigned char *) malloc(256); |
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94 | |||
95 | for (j=0; j<cr_values[0]; j++) { |
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96 | *cmark++ = 0; |
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97 | } |
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98 | |||
99 | for (j=0; j<(CR_RANGE-1); j++) { |
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100 | err_range = cr_values[j+1] - cr_values[j]; |
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101 | threshval = ((i * err_range) / DITH_SIZE)+cr_values[j]; |
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102 | |||
103 | for (k=cr_values[j]; k<cr_values[j+1]; k++) { |
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104 | if (k > threshval) { |
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105 | *cmark++ = ((j+1) * CB_RANGE); |
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106 | } |
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107 | else { |
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108 | *cmark++ = (j * CB_RANGE); |
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109 | } |
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110 | } |
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111 | } |
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112 | |||
113 | for (j=cr_values[CR_RANGE-1]; j<256; j++) { |
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114 | *cmark++ = (CR_RANGE-1)*(CB_RANGE); |
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115 | } |
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116 | } |
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117 | |||
118 | for (i=0; i<DITH_SIZE; i++) { |
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119 | cmark = cb_darrays[i] = (unsigned char *) malloc(256); |
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120 | |||
121 | for (j=0; j<cb_values[0]; j++) { |
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122 | *cmark++ = 0; |
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123 | } |
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124 | |||
125 | for (j=0; j<(CB_RANGE-1); j++) { |
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126 | err_range = cb_values[j+1] - cb_values[j]; |
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127 | threshval = ((i * err_range) / DITH_SIZE)+cb_values[j]; |
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128 | |||
129 | for (k=cb_values[j]; k<cb_values[j+1]; k++) { |
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130 | if (k > threshval) { |
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131 | *cmark++ = j+1; |
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132 | } |
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133 | else { |
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134 | *cmark++ = j; |
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135 | } |
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136 | } |
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137 | } |
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138 | |||
139 | for (j=cb_values[CB_RANGE-1]; j<256; j++) { |
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140 | *cmark++ = CB_RANGE-1; |
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141 | } |
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142 | } |
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143 | } |
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144 | |||
145 | |||
146 | /* |
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147 | *-------------------------------------------------------------- |
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148 | * |
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149 | * OrderedDitherImage -- |
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150 | * |
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151 | * Dithers an image using an ordered dither. |
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152 | * Assumptions made: |
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153 | * 1) The color space is allocated y:cr:cb = 8:4:4 |
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154 | * 2) The spatial resolution of y:cr:cb is 4:1:1 |
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155 | * The channels are dithered based on the standard |
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156 | * ordered dither pattern for a 4x4 area. |
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157 | * |
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158 | * Results: |
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159 | * None. |
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160 | * |
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161 | * Side effects: |
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162 | * None. |
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163 | * |
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164 | *-------------------------------------------------------------- |
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165 | */ |
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166 | void |
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167 | OrderedDitherImage (lum, cr, cb, out, h, w) |
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168 | unsigned char *lum; |
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169 | unsigned char *cr; |
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170 | unsigned char *cb; |
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171 | unsigned char *out; |
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172 | int w, h; |
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173 | { |
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174 | unsigned char *l, *r, *b, *o1, *o2; |
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175 | unsigned char *l2; |
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176 | unsigned char L, R, B; |
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177 | int i, j; |
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178 | |||
179 | l = lum; |
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180 | l2 = lum+w; |
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181 | r = cr; |
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182 | b = cb; |
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183 | o1 = out; |
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184 | o2 = out+w; |
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185 | |||
186 | for (i=0; i<h; i+=4) { |
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187 | |||
188 | for (j=0; j<w; j+=8) { |
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189 | |||
190 | R = r[0]; B = b[0]; |
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191 | |||
192 | L = l[0]; |
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193 | o1[0] = pixel[(l_darrays[0][L] + cr_darrays[0][R] + cb_darrays[0][B])]; |
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194 | L = l[1]; |
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195 | o1[1] = pixel[(l_darrays[8][L] + cr_darrays[8][R] + cb_darrays[8][B])]; |
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196 | L = l2[0]; |
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197 | o2[0] = pixel[(l_darrays[12][L] + cr_darrays[12][R] + cb_darrays[12][B])]; |
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198 | L = l2[1]; |
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199 | o2[1] = pixel[(l_darrays[4][L] + cr_darrays[4][R] + cb_darrays[4][B])]; |
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200 | |||
201 | R = r[1]; B = b[1]; |
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202 | |||
203 | L = l[2]; |
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204 | o1[2] = pixel[(l_darrays[2][L] + cr_darrays[2][R] + cb_darrays[2][B])]; |
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205 | L = l[3]; |
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206 | o1[3] = pixel[(l_darrays[10][L] + cr_darrays[10][R] + cb_darrays[10][B])]; |
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207 | L = l2[2]; |
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208 | o2[2] = pixel[(l_darrays[14][L] + cr_darrays[14][R] + cb_darrays[14][B])]; |
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209 | L = l2[3]; |
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210 | o2[3] = pixel[(l_darrays[6][L] + cr_darrays[6][R] + cb_darrays[6][B])]; |
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211 | |||
212 | R = r[2]; B = b[2]; |
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213 | |||
214 | L = l[4]; |
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215 | o1[4] = pixel[(l_darrays[0][L] + cr_darrays[0][R] + cb_darrays[0][B])]; |
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216 | L = l[5]; |
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217 | o1[5] = pixel[(l_darrays[8][L] + cr_darrays[8][R] + cb_darrays[8][B])]; |
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218 | L = l2[4]; |
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219 | o2[4] = pixel[(l_darrays[12][L] + cr_darrays[12][R] + cb_darrays[12][B])]; |
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220 | L = l2[5]; |
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221 | o2[5] = pixel[(l_darrays[4][L] + cr_darrays[4][R] + cb_darrays[4][B])]; |
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222 | |||
223 | R = r[3]; B = b[3]; |
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224 | |||
225 | L = l[6]; |
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226 | o1[6] = pixel[(l_darrays[2][L] + cr_darrays[2][R] + cb_darrays[2][B])]; |
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227 | L = l[7]; |
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228 | o1[7] = pixel[(l_darrays[10][L] + cr_darrays[10][R] + cb_darrays[10][B])]; |
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229 | L = l2[6]; |
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230 | o2[6] = pixel[(l_darrays[14][L] + cr_darrays[14][R] + cb_darrays[14][B])]; |
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231 | L = l2[7]; |
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232 | o2[7] = pixel[(l_darrays[6][L] + cr_darrays[6][R] + cb_darrays[6][B])]; |
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233 | |||
234 | l += 8; |
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235 | l2 += 8; |
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236 | r += 4; |
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237 | b += 4; |
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238 | o1 += 8; |
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239 | o2 += 8; |
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240 | } |
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241 | |||
242 | l += w; |
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243 | l2 += w; |
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244 | o1 += w; |
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245 | o2 += w; |
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246 | |||
247 | for (j=0; j<w; j+=8) { |
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248 | |||
249 | R = r[0]; B = b[0]; |
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250 | |||
251 | L = l[0]; |
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252 | o1[0] = pixel[(l_darrays[3][L] + cr_darrays[3][R] + cb_darrays[3][B])]; |
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253 | L = l[1]; |
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254 | o1[1] = pixel[(l_darrays[11][L] + cr_darrays[11][R] + cb_darrays[11][B])]; |
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255 | L = l2[0]; |
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256 | o2[0] = pixel[(l_darrays[15][L] + cr_darrays[15][R] + cb_darrays[15][B])]; |
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257 | L = l2[1]; |
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258 | o2[1] = pixel[(l_darrays[7][L] + cr_darrays[7][R] + cb_darrays[7][B])]; |
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259 | |||
260 | R = r[1]; B = b[1]; |
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261 | |||
262 | L = l[2]; |
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263 | o1[2] = pixel[(l_darrays[1][L] + cr_darrays[1][R] + cb_darrays[1][B])]; |
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264 | L = l[3]; |
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265 | o1[3] = pixel[(l_darrays[9][L] + cr_darrays[9][R] + cb_darrays[9][B])]; |
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266 | L = l2[2]; |
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267 | o2[2] = pixel[(l_darrays[13][L] + cr_darrays[13][R] + cb_darrays[13][B])]; |
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268 | L = l2[3]; |
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269 | o2[3] = pixel[(l_darrays[5][L] + cr_darrays[5][R] + cb_darrays[5][B])]; |
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270 | |||
271 | R = r[2]; B = b[2]; |
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272 | |||
273 | L = l[4]; |
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274 | o1[4] = pixel[(l_darrays[3][L] + cr_darrays[3][R] + cb_darrays[3][B])]; |
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275 | L = l[5]; |
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276 | o1[5] = pixel[(l_darrays[11][L] + cr_darrays[11][R] + cb_darrays[11][B])]; |
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277 | L = l2[4]; |
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278 | o2[4] = pixel[(l_darrays[15][L] + cr_darrays[15][R] + cb_darrays[15][B])]; |
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279 | L = l2[5]; |
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280 | o2[5] = pixel[(l_darrays[7][L] + cr_darrays[7][R] + cb_darrays[7][B])]; |
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281 | |||
282 | R = r[3]; B = b[3]; |
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283 | |||
284 | L = l[6]; |
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285 | o1[6] = pixel[(l_darrays[1][L] + cr_darrays[1][R] + cb_darrays[1][B])]; |
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286 | L = l[7]; |
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287 | o1[7] = pixel[(l_darrays[9][L] + cr_darrays[9][R] + cb_darrays[9][B])]; |
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288 | L = l2[6]; |
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289 | o2[6] = pixel[(l_darrays[13][L] + cr_darrays[13][R] + cb_darrays[13][B])]; |
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290 | L = l2[7]; |
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291 | o2[7] = pixel[(l_darrays[5][L] + cr_darrays[5][R] + cb_darrays[5][B])]; |
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292 | |||
293 | l += 8; |
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294 | l2 += 8; |
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295 | r += 4; |
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296 | b += 4; |
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297 | o1 += 8; |
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298 | o2 += 8; |
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299 | } |
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300 | |||
301 | l += w; |
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302 | l2 += w; |
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303 | o1 += w; |
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304 | o2 += w; |
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305 | } |
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306 | } |
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307 | |||
308 | |||
309 |