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428
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1 /* Image processing functions
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2 Copyright (C) 1998 Jareth Hein
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3
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4 This file is a part of XEmacs
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5
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6 XEmacs is free software; you can redistribute it and/or modify it
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7 under the terms of the GNU General Public License as published by the
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8 Free Software Foundation; either version 2, or (at your option) any
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9 later version.
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10
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11 XEmacs is distributed in the hope that it will be useful, but WITHOUT
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12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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14 for more details.
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15
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16 You should have received a copy of the GNU General Public License
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17 along with XEmacs; see the file COPYING. If not, write to
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18 the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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19 Boston, MA 02111-1307, USA. */
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20
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21 /* Synched up with: Not in FSF. */
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22
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23 /* Original author: Jareth Hein */
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24
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25 /* Parts of this file are based on code from Sam Leffler's tiff library,
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26 with the original copyright displayed here:
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27
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28 Copyright (c) 1988-1997 Sam Leffler
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29 Copyright (c) 1991-1997 Silicon Graphics, Inc.
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30
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31 Permission to use, copy, modify, distribute, and sell this software and
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32 its documentation for any purpose is hereby granted without fee, provided
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33 that (i) the above copyright notices and this permission notice appear in
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34 all copies of the software and related documentation, and (ii) the names of
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35 Sam Leffler and Silicon Graphics may not be used in any advertising or
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36 publicity relating to the software without the specific, prior written
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37 permission of Sam Leffler and Silicon Graphics. */
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38
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39 /* Quantizing code based off of the paper
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40 Color Image Quantization for Frame Buffer Display, Paul Heckbert,
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41 Siggraph '82 proceedings, pp. 297-307 */
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42
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43 #include <config.h>
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44 #include "lisp.h"
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45 #include "imgproc.h"
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46
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47 static void
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647
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48 get_histogram(quant_table *qt, UChar_Binary *pic,
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428
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49 int width, int height, Colorbox* box)
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50 {
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647
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51 register UChar_Binary *inptr;
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428
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52 register int red, green, blue;
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647
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53 register int j, i;
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428
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54
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55 box->rmin = box->gmin = box->bmin = 999;
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56 box->rmax = box->gmax = box->bmax = -1;
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57 box->total = width * height;
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58
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59 inptr = pic;
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60 for (i = 0; i < height; i++)
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61 {
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62 for (j = width; j-- > 0;)
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63 {
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64 red = *inptr++ >> COLOR_SHIFT;
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65 green = *inptr++ >> COLOR_SHIFT;
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66 blue = *inptr++ >> COLOR_SHIFT;
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67 if (red < box->rmin)
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68 box->rmin = red;
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69 if (red > box->rmax)
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70 box->rmax = red;
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71 if (green < box->gmin)
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72 box->gmin = green;
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73 if (green > box->gmax)
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74 box->gmax = green;
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75 if (blue < box->bmin)
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76 box->bmin = blue;
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77 if (blue > box->bmax)
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78 box->bmax = blue;
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79 qt->histogram[red][green][blue]++;
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80 }
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81 }
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82 }
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83
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84 static Colorbox *
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85 largest_box(quant_table *qt)
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86 {
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87 register Colorbox *p, *b;
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88 register int size;
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89
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90 b = NULL;
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91 size = -1;
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92 for (p = qt->usedboxes; p != NULL; p = p->next)
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93 if ((p->rmax > p->rmin || p->gmax > p->gmin ||
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94 p->bmax > p->bmin) && p->total > size)
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95 size = (b = p)->total;
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96 return (b);
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97 }
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98
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99 static void
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100 shrinkbox(quant_table *qt, Colorbox* box)
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101 {
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102 register int *histp, ir, ig, ib;
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103
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104 if (box->rmax > box->rmin)
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105 {
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106 for (ir = box->rmin; ir <= box->rmax; ++ir)
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107 for (ig = box->gmin; ig <= box->gmax; ++ig)
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108 {
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109 histp = &(qt->histogram[ir][ig][box->bmin]);
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110 for (ib = box->bmin; ib <= box->bmax; ++ib)
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111 if (*histp++ != 0)
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112 {
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113 box->rmin = ir;
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114 goto have_rmin;
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115 }
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116 }
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117 have_rmin:
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118 if (box->rmax > box->rmin)
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119 for (ir = box->rmax; ir >= box->rmin; --ir)
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120 for (ig = box->gmin; ig <= box->gmax; ++ig)
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121 {
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122 histp = &(qt->histogram[ir][ig][box->bmin]);
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123 ib = box->bmin;
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124 for (; ib <= box->bmax; ++ib)
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125 if (*histp++ != 0)
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126 {
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127 box->rmax = ir;
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128 goto have_rmax;
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129 }
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130 }
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131 }
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132 have_rmax:
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133 if (box->gmax > box->gmin)
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134 {
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135 for (ig = box->gmin; ig <= box->gmax; ++ig)
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136 for (ir = box->rmin; ir <= box->rmax; ++ir)
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137 {
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138 histp = &(qt->histogram[ir][ig][box->bmin]);
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139 for (ib = box->bmin; ib <= box->bmax; ++ib)
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140 if (*histp++ != 0)
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141 {
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142 box->gmin = ig;
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143 goto have_gmin;
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144 }
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145 }
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146 have_gmin:
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147 if (box->gmax > box->gmin)
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148 for (ig = box->gmax; ig >= box->gmin; --ig)
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149 for (ir = box->rmin; ir <= box->rmax; ++ir)
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150 {
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151 histp = &(qt->histogram[ir][ig][box->bmin]);
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152 ib = box->bmin;
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153 for (; ib <= box->bmax; ++ib)
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154 if (*histp++ != 0)
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155 {
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156 box->gmax = ig;
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157 goto have_gmax;
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158 }
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159 }
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160 }
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161 have_gmax:
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162 if (box->bmax > box->bmin)
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163 {
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164 for (ib = box->bmin; ib <= box->bmax; ++ib)
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165 for (ir = box->rmin; ir <= box->rmax; ++ir)
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166 {
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167 histp = &(qt->histogram[ir][box->gmin][ib]);
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168 for (ig = box->gmin; ig <= box->gmax; ++ig)
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169 {
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170 if (*histp != 0)
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171 {
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172 box->bmin = ib;
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173 goto have_bmin;
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174 }
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175 histp += B_LEN;
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176 }
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177 }
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178 have_bmin:
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179 if (box->bmax > box->bmin)
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180 for (ib = box->bmax; ib >= box->bmin; --ib)
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181 for (ir = box->rmin; ir <= box->rmax; ++ir)
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182 {
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183 histp = &(qt->histogram[ir][box->gmin][ib]);
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184 ig = box->gmin;
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185 for (; ig <= box->gmax; ++ig)
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186 {
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187 if (*histp != 0)
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188 {
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189 box->bmax = ib;
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190 goto have_bmax;
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191 }
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192 histp += B_LEN;
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193 }
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194 }
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195 }
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196 have_bmax:
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197 ;
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198 }
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199
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200 static void
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201 splitbox(quant_table *qt, Colorbox* ptr)
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202 {
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203 int hist2[B_LEN];
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204 int first = 0, last = 0;
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205 register Colorbox *new;
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206 register int *iptr, *histp;
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207 register int i, j;
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208 register int ir,ig,ib;
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209 register int sum, sum1, sum2;
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210 enum { RED, GREEN, BLUE } axis;
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211
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212 /*
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213 * See which axis is the largest, do a histogram along that
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214 * axis. Split at median point. Contract both new boxes to
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215 * fit points and return
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216 */
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217 i = ptr->rmax - ptr->rmin;
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218 if (i >= ptr->gmax - ptr->gmin && i >= ptr->bmax - ptr->bmin)
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219 axis = RED;
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220 else if (ptr->gmax - ptr->gmin >= ptr->bmax - ptr->bmin)
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221 axis = GREEN;
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222 else
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223 axis = BLUE;
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224 /* get histogram along longest axis */
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225 switch (axis)
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226 {
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227 case RED:
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228 histp = &hist2[ptr->rmin];
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229 for (ir = ptr->rmin; ir <= ptr->rmax; ++ir)
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230 {
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231 *histp = 0;
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232 for (ig = ptr->gmin; ig <= ptr->gmax; ++ig)
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233 {
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234 iptr = &(qt->histogram[ir][ig][ptr->bmin]);
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235 for (ib = ptr->bmin; ib <= ptr->bmax; ++ib)
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236 *histp += *iptr++;
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237 }
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238 histp++;
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239 }
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240 first = ptr->rmin;
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241 last = ptr->rmax;
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242 break;
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243 case GREEN:
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244 histp = &hist2[ptr->gmin];
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245 for (ig = ptr->gmin; ig <= ptr->gmax; ++ig)
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246 {
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247 *histp = 0;
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248 for (ir = ptr->rmin; ir <= ptr->rmax; ++ir)
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249 {
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250 iptr = &(qt->histogram[ir][ig][ptr->bmin]);
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251 for (ib = ptr->bmin; ib <= ptr->bmax; ++ib)
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252 *histp += *iptr++;
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253 }
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254 histp++;
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255 }
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256 first = ptr->gmin;
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257 last = ptr->gmax;
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258 break;
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259 case BLUE:
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260 histp = &hist2[ptr->bmin];
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261 for (ib = ptr->bmin; ib <= ptr->bmax; ++ib)
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262 {
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263 *histp = 0;
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264 for (ir = ptr->rmin; ir <= ptr->rmax; ++ir)
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265 {
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266 iptr = &(qt->histogram[ir][ptr->gmin][ib]);
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267 for (ig = ptr->gmin; ig <= ptr->gmax; ++ig)
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268 {
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269 *histp += *iptr;
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270 iptr += B_LEN;
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271 }
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272 }
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273 histp++;
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274 }
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275 first = ptr->bmin;
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276 last = ptr->bmax;
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277 break;
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278 }
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279 /* find median point */
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280 sum2 = ptr->total / 2;
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281 histp = &hist2[first];
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282 sum = 0;
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283 for (i = first; i <= last && (sum += *histp++) < sum2; ++i)
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284 ;
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285 if (i == first)
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286 i++;
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287
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288 /* Create new box, re-allocate points */
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289 new = qt->freeboxes;
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290 qt->freeboxes = new->next;
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291 if (qt->freeboxes)
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292 qt->freeboxes->prev = NULL;
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293 if (qt->usedboxes)
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294 qt->usedboxes->prev = new;
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295 new->next = qt->usedboxes;
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296 qt->usedboxes = new;
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297
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298 histp = &hist2[first];
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299 for (sum1 = 0, j = first; j < i; j++)
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300 sum1 += *histp++;
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301 for (sum2 = 0, j = i; j <= last; j++)
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302 sum2 += *histp++;
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303 new->total = sum1;
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304 ptr->total = sum2;
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305
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306 new->rmin = ptr->rmin;
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307 new->rmax = ptr->rmax;
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308 new->gmin = ptr->gmin;
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309 new->gmax = ptr->gmax;
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310 new->bmin = ptr->bmin;
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311 new->bmax = ptr->bmax;
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312 switch (axis)
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313 {
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314 case RED:
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315 new->rmax = i-1;
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316 ptr->rmin = i;
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317 break;
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318 case GREEN:
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319 new->gmax = i-1;
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320 ptr->gmin = i;
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321 break;
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322 case BLUE:
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323 new->bmax = i-1;
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324 ptr->bmin = i;
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325 break;
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326 }
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327 shrinkbox (qt, new);
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328 shrinkbox (qt, ptr);
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329 }
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330
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331
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332 static C_cell *
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333 create_colorcell(quant_table *qt, int num_colors, int red, int green, int blue)
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334 {
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335 register int ir, ig, ib, i;
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336 register C_cell *ptr;
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337 int mindist, next_n;
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338 register int tmp, dist, n;
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339
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340 ir = red >> (COLOR_DEPTH-C_DEPTH);
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341 ig = green >> (COLOR_DEPTH-C_DEPTH);
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342 ib = blue >> (COLOR_DEPTH-C_DEPTH);
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343 ptr = (C_cell *)xmalloc(sizeof (C_cell));
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344 *(qt->ColorCells + ir*C_LEN*C_LEN + ig*C_LEN + ib) = ptr;
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345 ptr->num_ents = 0;
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346
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347 /*
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348 * Step 1: find all colors inside this cell, while we're at
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349 * it, find distance of centermost point to furthest corner
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350 */
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351 mindist = 99999999;
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352 for (i = 0; i < num_colors; ++i)
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353 {
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354 if (qt->rm[i]>>(COLOR_DEPTH-C_DEPTH) != ir ||
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355 qt->gm[i]>>(COLOR_DEPTH-C_DEPTH) != ig ||
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356 qt->bm[i]>>(COLOR_DEPTH-C_DEPTH) != ib)
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357 continue;
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358 ptr->entries[ptr->num_ents][0] = i;
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359 ptr->entries[ptr->num_ents][1] = 0;
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360 ++ptr->num_ents;
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361 tmp = qt->rm[i] - red;
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362 if (tmp < (MAX_COLOR/C_LEN/2))
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363 tmp = MAX_COLOR/C_LEN-1 - tmp;
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364 dist = tmp*tmp;
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365 tmp = qt->gm[i] - green;
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366 if (tmp < (MAX_COLOR/C_LEN/2))
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367 tmp = MAX_COLOR/C_LEN-1 - tmp;
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368 dist += tmp*tmp;
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369 tmp = qt->bm[i] - blue;
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370 if (tmp < (MAX_COLOR/C_LEN/2))
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371 tmp = MAX_COLOR/C_LEN-1 - tmp;
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372 dist += tmp*tmp;
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373 if (dist < mindist)
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374 mindist = dist;
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375 }
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376
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377 /*
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378 * Step 3: find all points within that distance to cell.
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379 */
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380 for (i = 0; i < num_colors; ++i)
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381 {
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382 if (qt->rm[i] >> (COLOR_DEPTH-C_DEPTH) == ir &&
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383 qt->gm[i] >> (COLOR_DEPTH-C_DEPTH) == ig &&
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384 qt->bm[i] >> (COLOR_DEPTH-C_DEPTH) == ib)
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385 continue;
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386 dist = 0;
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387 if ((tmp = red - qt->rm[i]) > 0 ||
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388 (tmp = qt->rm[i] - (red + MAX_COLOR/C_LEN-1)) > 0 )
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389 dist += tmp*tmp;
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390 if ((tmp = green - qt->gm[i]) > 0 ||
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391 (tmp = qt->gm[i] - (green + MAX_COLOR/C_LEN-1)) > 0 )
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392 dist += tmp*tmp;
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393 if ((tmp = blue - qt->bm[i]) > 0 ||
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394 (tmp = qt->bm[i] - (blue + MAX_COLOR/C_LEN-1)) > 0 )
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395 dist += tmp*tmp;
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396 if (dist < mindist)
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397 {
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398 ptr->entries[ptr->num_ents][0] = i;
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399 ptr->entries[ptr->num_ents][1] = dist;
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400 ++ptr->num_ents;
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401 }
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402 }
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403
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404 /*
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|
405 * Sort color cells by distance, use cheap exchange sort
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406 */
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407 for (n = ptr->num_ents - 1; n > 0; n = next_n)
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408 {
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409 next_n = 0;
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410 for (i = 0; i < n; ++i)
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411 if (ptr->entries[i][1] > ptr->entries[i+1][1])
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412 {
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413 tmp = ptr->entries[i][0];
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414 ptr->entries[i][0] = ptr->entries[i+1][0];
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415 ptr->entries[i+1][0] = tmp;
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416 tmp = ptr->entries[i][1];
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417 ptr->entries[i][1] = ptr->entries[i+1][1];
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418 ptr->entries[i+1][1] = tmp;
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419 next_n = i;
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420 }
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421 }
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422 return (ptr);
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423 }
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424
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425 static int
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426 map_colortable(quant_table *qt, int num_colors)
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427 {
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428 register int *histp = &(qt->histogram[0][0][0]);
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429 register C_cell *cell;
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430 register int j, tmp, d2, dist;
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431 int ir, ig, ib, i;
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432
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433 for (ir = 0; ir < B_LEN; ++ir)
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434 for (ig = 0; ig < B_LEN; ++ig)
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435 for (ib = 0; ib < B_LEN; ++ib, histp++)
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436 {
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437 if (*histp == 0)
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438 {
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439 *histp = -1;
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440 continue;
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441 }
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442 cell = *(qt->ColorCells +
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443 (((ir>>(B_DEPTH-C_DEPTH)) << C_DEPTH*2) +
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444 ((ig>>(B_DEPTH-C_DEPTH)) << C_DEPTH) +
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445 (ib>>(B_DEPTH-C_DEPTH))));
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446 if (cell == NULL )
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447 cell = create_colorcell (qt, num_colors,
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448 ir << COLOR_SHIFT,
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449 ig << COLOR_SHIFT,
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450 ib << COLOR_SHIFT);
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451 if (cell == NULL) /* memory exhausted! punt! */
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452 return -1;
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453 dist = 9999999;
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454 for (i = 0; i < cell->num_ents &&
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455 dist > cell->entries[i][1]; ++i)
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456 {
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457 j = cell->entries[i][0];
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458 d2 = qt->rm[j] - (ir << COLOR_SHIFT);
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459 d2 *= d2;
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|
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460 tmp = qt->gm[j] - (ig << COLOR_SHIFT);
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|
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461 d2 += tmp*tmp;
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462 tmp = qt->bm[j] - (ib << COLOR_SHIFT);
|
|
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463 d2 += tmp*tmp;
|
|
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464 if (d2 < dist)
|
|
|
465 {
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|
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466 dist = d2;
|
|
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467 *histp = j;
|
|
|
468 }
|
|
|
469 }
|
|
|
470 }
|
|
|
471 return 0;
|
|
|
472 }
|
|
|
473
|
|
|
474 quant_table *
|
|
647
|
475 build_EImage_quantable(UChar_Binary *eimage, int width, int height, int num_colors)
|
|
428
|
476 {
|
|
|
477 quant_table *qt;
|
|
|
478 Colorbox *box_list, *ptr;
|
|
|
479 int i,res;
|
|
|
480
|
|
|
481 qt = (quant_table*)xmalloc_and_zero (sizeof(quant_table));
|
|
|
482 if (qt == NULL) return NULL;
|
|
|
483
|
|
|
484 assert (num_colors < 257 && num_colors > 2);
|
|
|
485 /*
|
|
|
486 * STEP 1: create empty boxes
|
|
|
487 */
|
|
|
488 qt->usedboxes = NULL;
|
|
|
489 box_list = qt->freeboxes = (Colorbox *)xmalloc (num_colors*sizeof (Colorbox));
|
|
|
490 qt->freeboxes[0].next = &(qt->freeboxes[1]);
|
|
|
491 qt->freeboxes[0].prev = NULL;
|
|
|
492 for (i = 1; i < num_colors-1; ++i)
|
|
|
493 {
|
|
|
494 qt->freeboxes[i].next = &(qt->freeboxes[i+1]);
|
|
|
495 qt->freeboxes[i].prev = &(qt->freeboxes[i-1]);
|
|
|
496 }
|
|
|
497 qt->freeboxes[num_colors-1].next = NULL;
|
|
|
498 qt->freeboxes[num_colors-1].prev = &(qt->freeboxes[num_colors-2]);
|
|
|
499
|
|
|
500 /*
|
|
|
501 * STEP 2: get histogram, initialize first box
|
|
|
502 */
|
|
|
503 ptr = qt->freeboxes;
|
|
|
504 qt->freeboxes = ptr->next;
|
|
|
505 if (qt->freeboxes)
|
|
|
506 qt->freeboxes->prev = NULL;
|
|
|
507 ptr->next = qt->usedboxes;
|
|
|
508 qt->usedboxes = ptr;
|
|
|
509 if (ptr->next)
|
|
|
510 ptr->next->prev = ptr;
|
|
|
511 get_histogram (qt, eimage, width, height, ptr);
|
|
|
512
|
|
|
513 /*
|
|
|
514 * STEP 3: continually subdivide boxes until no more free
|
|
|
515 * boxes remain or until all colors assigned.
|
|
|
516 */
|
|
|
517 while (qt->freeboxes != NULL)
|
|
|
518 {
|
|
|
519 ptr = largest_box(qt);
|
|
|
520 if (ptr != NULL)
|
|
|
521 splitbox (qt, ptr);
|
|
|
522 else
|
|
|
523 qt->freeboxes = NULL;
|
|
|
524 }
|
|
|
525
|
|
|
526 /*
|
|
|
527 * STEP 4: assign colors to all boxes
|
|
|
528 */
|
|
|
529 for (i = 0, ptr = qt->usedboxes; ptr != NULL; ++i, ptr = ptr->next)
|
|
|
530 {
|
|
|
531 qt->rm[i] = ((ptr->rmin + ptr->rmax) << COLOR_SHIFT) / 2;
|
|
|
532 qt->gm[i] = ((ptr->gmin + ptr->gmax) << COLOR_SHIFT) / 2;
|
|
|
533 qt->bm[i] = ((ptr->bmin + ptr->bmax) << COLOR_SHIFT) / 2;
|
|
|
534 qt->um[i] = ptr->total;
|
|
|
535 }
|
|
|
536 qt->num_active_colors = i;
|
|
|
537
|
|
|
538 /* We're done with the boxes now */
|
|
|
539 xfree (box_list);
|
|
|
540 qt->freeboxes = qt->usedboxes = NULL;
|
|
|
541
|
|
|
542 /*
|
|
|
543 * STEP 5: scan histogram and map all values to closest color
|
|
|
544 */
|
|
|
545 /* 5a: create cell list as described in Heckbert */
|
|
|
546 qt->ColorCells = (C_cell **)xmalloc_and_zero (C_LEN*C_LEN*C_LEN*sizeof (C_cell*));
|
|
|
547 /* 5b: create mapping from truncated pixel space to color
|
|
|
548 table entries */
|
|
|
549 res = map_colortable (qt, num_colors);
|
|
|
550
|
|
|
551 /* 5c: done with ColorCells */
|
|
|
552 for (i = 0; i < C_LEN*C_LEN*C_LEN; i++)
|
|
|
553 if (qt->ColorCells[i]) xfree (qt->ColorCells[i]);
|
|
|
554 xfree (qt->ColorCells);
|
|
|
555
|
|
|
556 if (res)
|
|
|
557 {
|
|
|
558 /* we failed in memory allocation, so clean up an leave */
|
|
|
559 xfree(qt);
|
|
|
560 return NULL;
|
|
|
561 }
|
|
|
562
|
|
|
563 return qt;
|
|
|
564 }
|
