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6417 | ashmew2 | 1 | /* |
2 | * wrppm.c |
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3 | * |
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4 | * Copyright (C) 1991-1996, Thomas G. Lane. |
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5 | * This file is part of the Independent JPEG Group's software. |
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6 | * For conditions of distribution and use, see the accompanying README file. |
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7 | * |
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8 | * This file contains routines to write output images in PPM/PGM format. |
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9 | * The extended 2-byte-per-sample raw PPM/PGM formats are supported. |
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10 | * The PBMPLUS library is NOT required to compile this software |
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11 | * (but it is highly useful as a set of PPM image manipulation programs). |
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12 | * |
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13 | * These routines may need modification for non-Unix environments or |
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14 | * specialized applications. As they stand, they assume output to |
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15 | * an ordinary stdio stream. |
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16 | */ |
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17 | |||
18 | #include "cdjpeg.h" /* Common decls for cjpeg/djpeg applications */ |
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19 | |||
20 | #ifdef PPM_SUPPORTED |
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21 | |||
22 | |||
23 | /* |
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24 | * For 12-bit JPEG data, we either downscale the values to 8 bits |
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25 | * (to write standard byte-per-sample PPM/PGM files), or output |
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26 | * nonstandard word-per-sample PPM/PGM files. Downscaling is done |
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27 | * if PPM_NORAWWORD is defined (this can be done in the Makefile |
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28 | * or in jconfig.h). |
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29 | * (When the core library supports data precision reduction, a cleaner |
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30 | * implementation will be to ask for that instead.) |
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31 | */ |
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32 | |||
33 | #if BITS_IN_JSAMPLE == 8 |
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34 | #define PUTPPMSAMPLE(ptr,v) *ptr++ = (char) (v) |
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35 | #define BYTESPERSAMPLE 1 |
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36 | #define PPM_MAXVAL 255 |
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37 | #else |
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38 | #ifdef PPM_NORAWWORD |
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39 | #define PUTPPMSAMPLE(ptr,v) *ptr++ = (char) ((v) >> (BITS_IN_JSAMPLE-8)) |
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40 | #define BYTESPERSAMPLE 1 |
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41 | #define PPM_MAXVAL 255 |
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42 | #else |
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43 | /* The word-per-sample format always puts the LSB first. */ |
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44 | #define PUTPPMSAMPLE(ptr,v) \ |
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45 | { register int val_ = v; \ |
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46 | *ptr++ = (char) (val_ & 0xFF); \ |
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47 | *ptr++ = (char) ((val_ >> 8) & 0xFF); \ |
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48 | } |
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49 | #define BYTESPERSAMPLE 2 |
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50 | #define PPM_MAXVAL ((1< |
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51 | #endif |
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52 | #endif |
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53 | |||
54 | |||
55 | /* |
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56 | * When JSAMPLE is the same size as char, we can just fwrite() the |
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57 | * decompressed data to the PPM or PGM file. On PCs, in order to make this |
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58 | * work the output buffer must be allocated in near data space, because we are |
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59 | * assuming small-data memory model wherein fwrite() can't reach far memory. |
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60 | * If you need to process very wide images on a PC, you might have to compile |
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61 | * in large-memory model, or else replace fwrite() with a putc() loop --- |
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62 | * which will be much slower. |
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63 | */ |
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64 | |||
65 | |||
66 | /* Private version of data destination object */ |
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67 | |||
68 | typedef struct { |
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69 | struct djpeg_dest_struct pub; /* public fields */ |
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70 | |||
71 | /* Usually these two pointers point to the same place: */ |
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72 | char *iobuffer; /* fwrite's I/O buffer */ |
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73 | JSAMPROW pixrow; /* decompressor output buffer */ |
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74 | size_t buffer_width; /* width of I/O buffer */ |
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75 | JDIMENSION samples_per_row; /* JSAMPLEs per output row */ |
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76 | } ppm_dest_struct; |
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77 | |||
78 | typedef ppm_dest_struct * ppm_dest_ptr; |
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79 | |||
80 | |||
81 | /* |
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82 | * Write some pixel data. |
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83 | * In this module rows_supplied will always be 1. |
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84 | * |
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85 | * put_pixel_rows handles the "normal" 8-bit case where the decompressor |
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86 | * output buffer is physically the same as the fwrite buffer. |
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87 | */ |
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88 | |||
89 | METHODDEF(void) |
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90 | put_pixel_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo, |
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91 | JDIMENSION rows_supplied) |
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92 | { |
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93 | ppm_dest_ptr dest = (ppm_dest_ptr) dinfo; |
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94 | |||
95 | (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width); |
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96 | } |
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97 | |||
98 | |||
99 | /* |
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100 | * This code is used when we have to copy the data and apply a pixel |
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101 | * format translation. Typically this only happens in 12-bit mode. |
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102 | */ |
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103 | |||
104 | METHODDEF(void) |
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105 | copy_pixel_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo, |
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106 | JDIMENSION rows_supplied) |
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107 | { |
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108 | ppm_dest_ptr dest = (ppm_dest_ptr) dinfo; |
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109 | register char * bufferptr; |
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110 | register JSAMPROW ptr; |
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111 | register JDIMENSION col; |
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112 | |||
113 | ptr = dest->pub.buffer[0]; |
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114 | bufferptr = dest->iobuffer; |
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115 | for (col = dest->samples_per_row; col > 0; col--) { |
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116 | PUTPPMSAMPLE(bufferptr, GETJSAMPLE(*ptr++)); |
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117 | } |
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118 | (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width); |
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119 | } |
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120 | |||
121 | |||
122 | /* |
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123 | * Write some pixel data when color quantization is in effect. |
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124 | * We have to demap the color index values to straight data. |
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125 | */ |
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126 | |||
127 | METHODDEF(void) |
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128 | put_demapped_rgb (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo, |
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129 | JDIMENSION rows_supplied) |
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130 | { |
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131 | ppm_dest_ptr dest = (ppm_dest_ptr) dinfo; |
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132 | register char * bufferptr; |
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133 | register int pixval; |
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134 | register JSAMPROW ptr; |
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135 | register JSAMPROW color_map0 = cinfo->colormap[0]; |
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136 | register JSAMPROW color_map1 = cinfo->colormap[1]; |
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137 | register JSAMPROW color_map2 = cinfo->colormap[2]; |
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138 | register JDIMENSION col; |
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139 | |||
140 | ptr = dest->pub.buffer[0]; |
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141 | bufferptr = dest->iobuffer; |
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142 | for (col = cinfo->output_width; col > 0; col--) { |
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143 | pixval = GETJSAMPLE(*ptr++); |
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144 | PUTPPMSAMPLE(bufferptr, GETJSAMPLE(color_map0[pixval])); |
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145 | PUTPPMSAMPLE(bufferptr, GETJSAMPLE(color_map1[pixval])); |
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146 | PUTPPMSAMPLE(bufferptr, GETJSAMPLE(color_map2[pixval])); |
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147 | } |
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148 | (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width); |
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149 | } |
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150 | |||
151 | |||
152 | METHODDEF(void) |
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153 | put_demapped_gray (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo, |
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154 | JDIMENSION rows_supplied) |
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155 | { |
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156 | ppm_dest_ptr dest = (ppm_dest_ptr) dinfo; |
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157 | register char * bufferptr; |
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158 | register JSAMPROW ptr; |
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159 | register JSAMPROW color_map = cinfo->colormap[0]; |
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160 | register JDIMENSION col; |
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161 | |||
162 | ptr = dest->pub.buffer[0]; |
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163 | bufferptr = dest->iobuffer; |
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164 | for (col = cinfo->output_width; col > 0; col--) { |
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165 | PUTPPMSAMPLE(bufferptr, GETJSAMPLE(color_map[GETJSAMPLE(*ptr++)])); |
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166 | } |
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167 | (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width); |
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168 | } |
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169 | |||
170 | |||
171 | /* |
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172 | * Startup: write the file header. |
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173 | */ |
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174 | |||
175 | METHODDEF(void) |
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176 | start_output_ppm (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo) |
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177 | { |
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178 | ppm_dest_ptr dest = (ppm_dest_ptr) dinfo; |
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179 | |||
180 | /* Emit file header */ |
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181 | switch (cinfo->out_color_space) { |
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182 | case JCS_GRAYSCALE: |
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183 | /* emit header for raw PGM format */ |
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184 | fprintf(dest->pub.output_file, "P5\n%ld %ld\n%d\n", |
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185 | (long) cinfo->output_width, (long) cinfo->output_height, |
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186 | PPM_MAXVAL); |
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187 | break; |
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188 | case JCS_RGB: |
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189 | /* emit header for raw PPM format */ |
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190 | fprintf(dest->pub.output_file, "P6\n%ld %ld\n%d\n", |
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191 | (long) cinfo->output_width, (long) cinfo->output_height, |
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192 | PPM_MAXVAL); |
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193 | break; |
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194 | default: |
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195 | ERREXIT(cinfo, JERR_PPM_COLORSPACE); |
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196 | } |
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197 | } |
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198 | |||
199 | |||
200 | /* |
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201 | * Finish up at the end of the file. |
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202 | */ |
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203 | |||
204 | METHODDEF(void) |
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205 | finish_output_ppm (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo) |
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206 | { |
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207 | /* Make sure we wrote the output file OK */ |
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208 | fflush(dinfo->output_file); |
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209 | if (ferror(dinfo->output_file)) |
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210 | ERREXIT(cinfo, JERR_FILE_WRITE); |
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211 | } |
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212 | |||
213 | |||
214 | /* |
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215 | * The module selection routine for PPM format output. |
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216 | */ |
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217 | |||
218 | GLOBAL(djpeg_dest_ptr) |
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219 | jinit_write_ppm (j_decompress_ptr cinfo) |
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220 | { |
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221 | ppm_dest_ptr dest; |
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222 | |||
223 | /* Create module interface object, fill in method pointers */ |
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224 | dest = (ppm_dest_ptr) |
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225 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
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226 | SIZEOF(ppm_dest_struct)); |
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227 | dest->pub.start_output = start_output_ppm; |
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228 | dest->pub.finish_output = finish_output_ppm; |
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229 | |||
230 | /* Calculate output image dimensions so we can allocate space */ |
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231 | jpeg_calc_output_dimensions(cinfo); |
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232 | |||
233 | /* Create physical I/O buffer. Note we make this near on a PC. */ |
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234 | dest->samples_per_row = cinfo->output_width * cinfo->out_color_components; |
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235 | dest->buffer_width = dest->samples_per_row * (BYTESPERSAMPLE * SIZEOF(char)); |
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236 | dest->iobuffer = (char *) (*cinfo->mem->alloc_small) |
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237 | ((j_common_ptr) cinfo, JPOOL_IMAGE, dest->buffer_width); |
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238 | |||
239 | if (cinfo->quantize_colors || BITS_IN_JSAMPLE != 8 || |
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240 | SIZEOF(JSAMPLE) != SIZEOF(char)) { |
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241 | /* When quantizing, we need an output buffer for colormap indexes |
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242 | * that's separate from the physical I/O buffer. We also need a |
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243 | * separate buffer if pixel format translation must take place. |
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244 | */ |
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245 | dest->pub.buffer = (*cinfo->mem->alloc_sarray) |
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246 | ((j_common_ptr) cinfo, JPOOL_IMAGE, |
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247 | cinfo->output_width * cinfo->output_components, (JDIMENSION) 1); |
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248 | dest->pub.buffer_height = 1; |
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249 | if (! cinfo->quantize_colors) |
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250 | dest->pub.put_pixel_rows = copy_pixel_rows; |
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251 | else if (cinfo->out_color_space == JCS_GRAYSCALE) |
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252 | dest->pub.put_pixel_rows = put_demapped_gray; |
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253 | else |
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254 | dest->pub.put_pixel_rows = put_demapped_rgb; |
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255 | } else { |
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256 | /* We will fwrite() directly from decompressor output buffer. */ |
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257 | /* Synthesize a JSAMPARRAY pointer structure */ |
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258 | /* Cast here implies near->far pointer conversion on PCs */ |
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259 | dest->pixrow = (JSAMPROW) dest->iobuffer; |
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260 | dest->pub.buffer = & dest->pixrow; |
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261 | dest->pub.buffer_height = 1; |
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262 | dest->pub.put_pixel_rows = put_pixel_rows; |
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263 | } |
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264 | |||
265 | return (djpeg_dest_ptr) dest; |
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266 | } |
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267 | |||
268 | #endif /* PPM_SUPPORTED */ |