1 | /* |
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2 | * wrtarga.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 Targa format. |
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9 | * |
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10 | * These routines may need modification for non-Unix environments or |
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11 | * specialized applications. As they stand, they assume output to |
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12 | * an ordinary stdio stream. |
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13 | * |
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14 | * Based on code contributed by Lee Daniel Crocker. |
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15 | */ |
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16 | |
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17 | #include "cdjpeg.h" /* Common decls for cjpeg/djpeg applications */ |
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18 | |
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19 | #ifdef TARGA_SUPPORTED |
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20 | |
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21 | |
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22 | /* |
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23 | * To support 12-bit JPEG data, we'd have to scale output down to 8 bits. |
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24 | * This is not yet implemented. |
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25 | */ |
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26 | |
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27 | #if BITS_IN_JSAMPLE != 8 |
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28 | Sorry, this code only copes with 8-bit JSAMPLEs. /* deliberate syntax err */ |
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29 | #endif |
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30 | |
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31 | /* |
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32 | * The output buffer needs to be writable by fwrite(). On PCs, we must |
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33 | * allocate the buffer in near data space, because we are assuming small-data |
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34 | * memory model, wherein fwrite() can't reach far memory. If you need to |
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35 | * process very wide images on a PC, you might have to compile in large-memory |
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36 | * model, or else replace fwrite() with a putc() loop --- which will be much |
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37 | * slower. |
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38 | */ |
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39 | |
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40 | |
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41 | /* Private version of data destination object */ |
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42 | |
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43 | typedef struct { |
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44 | struct djpeg_dest_struct pub; /* public fields */ |
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45 | |
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46 | char *iobuffer; /* physical I/O buffer */ |
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47 | JDIMENSION buffer_width; /* width of one row */ |
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48 | } tga_dest_struct; |
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49 | |
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50 | typedef tga_dest_struct * tga_dest_ptr; |
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51 | |
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52 | |
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53 | LOCAL(void) |
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54 | write_header (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo, int num_colors) |
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55 | /* Create and write a Targa header */ |
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56 | { |
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57 | char targaheader[18]; |
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58 | |
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59 | /* Set unused fields of header to 0 */ |
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60 | MEMZERO(targaheader, SIZEOF(targaheader)); |
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61 | |
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62 | if (num_colors > 0) { |
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63 | targaheader[1] = 1; /* color map type 1 */ |
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64 | targaheader[5] = (char) (num_colors & 0xFF); |
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65 | targaheader[6] = (char) (num_colors >> 8); |
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66 | targaheader[7] = 24; /* 24 bits per cmap entry */ |
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67 | } |
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68 | |
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69 | targaheader[12] = (char) (cinfo->output_width & 0xFF); |
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70 | targaheader[13] = (char) (cinfo->output_width >> 8); |
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71 | targaheader[14] = (char) (cinfo->output_height & 0xFF); |
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72 | targaheader[15] = (char) (cinfo->output_height >> 8); |
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73 | targaheader[17] = 0x20; /* Top-down, non-interlaced */ |
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74 | |
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75 | if (cinfo->out_color_space == JCS_GRAYSCALE) { |
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76 | targaheader[2] = 3; /* image type = uncompressed gray-scale */ |
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77 | targaheader[16] = 8; /* bits per pixel */ |
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78 | } else { /* must be RGB */ |
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79 | if (num_colors > 0) { |
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80 | targaheader[2] = 1; /* image type = colormapped RGB */ |
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81 | targaheader[16] = 8; |
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82 | } else { |
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83 | targaheader[2] = 2; /* image type = uncompressed RGB */ |
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84 | targaheader[16] = 24; |
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85 | } |
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86 | } |
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87 | |
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88 | if (JFWRITE(dinfo->output_file, targaheader, 18) != (size_t) 18) |
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89 | ERREXIT(cinfo, JERR_FILE_WRITE); |
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90 | } |
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91 | |
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92 | |
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93 | /* |
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94 | * Write some pixel data. |
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95 | * In this module rows_supplied will always be 1. |
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96 | */ |
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97 | |
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98 | METHODDEF(void) |
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99 | put_pixel_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo, |
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100 | JDIMENSION rows_supplied) |
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101 | /* used for unquantized full-color output */ |
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102 | { |
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103 | tga_dest_ptr dest = (tga_dest_ptr) dinfo; |
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104 | register JSAMPROW inptr; |
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105 | register char * outptr; |
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106 | register JDIMENSION col; |
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107 | |
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108 | inptr = dest->pub.buffer[0]; |
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109 | outptr = dest->iobuffer; |
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110 | for (col = cinfo->output_width; col > 0; col--) { |
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111 | outptr[0] = (char) GETJSAMPLE(inptr[2]); /* RGB to BGR order */ |
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112 | outptr[1] = (char) GETJSAMPLE(inptr[1]); |
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113 | outptr[2] = (char) GETJSAMPLE(inptr[0]); |
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114 | inptr += 3, outptr += 3; |
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115 | } |
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116 | (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width); |
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117 | } |
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118 | |
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119 | METHODDEF(void) |
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120 | put_gray_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo, |
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121 | JDIMENSION rows_supplied) |
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122 | /* used for grayscale OR quantized color output */ |
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123 | { |
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124 | tga_dest_ptr dest = (tga_dest_ptr) dinfo; |
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125 | register JSAMPROW inptr; |
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126 | register char * outptr; |
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127 | register JDIMENSION col; |
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128 | |
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129 | inptr = dest->pub.buffer[0]; |
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130 | outptr = dest->iobuffer; |
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131 | for (col = cinfo->output_width; col > 0; col--) { |
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132 | *outptr++ = (char) GETJSAMPLE(*inptr++); |
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133 | } |
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134 | (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width); |
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135 | } |
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136 | |
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137 | |
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138 | /* |
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139 | * Write some demapped pixel data when color quantization is in effect. |
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140 | * For Targa, this is only applied to grayscale data. |
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141 | */ |
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142 | |
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143 | METHODDEF(void) |
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144 | put_demapped_gray (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo, |
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145 | JDIMENSION rows_supplied) |
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146 | { |
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147 | tga_dest_ptr dest = (tga_dest_ptr) dinfo; |
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148 | register JSAMPROW inptr; |
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149 | register char * outptr; |
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150 | register JSAMPROW color_map0 = cinfo->colormap[0]; |
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151 | register JDIMENSION col; |
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152 | |
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153 | inptr = dest->pub.buffer[0]; |
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154 | outptr = dest->iobuffer; |
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155 | for (col = cinfo->output_width; col > 0; col--) { |
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156 | *outptr++ = (char) GETJSAMPLE(color_map0[GETJSAMPLE(*inptr++)]); |
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157 | } |
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158 | (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width); |
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159 | } |
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160 | |
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161 | |
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162 | /* |
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163 | * Startup: write the file header. |
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164 | */ |
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165 | |
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166 | METHODDEF(void) |
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167 | start_output_tga (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo) |
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168 | { |
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169 | tga_dest_ptr dest = (tga_dest_ptr) dinfo; |
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170 | int num_colors, i; |
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171 | FILE *outfile; |
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172 | |
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173 | if (cinfo->out_color_space == JCS_GRAYSCALE) { |
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174 | /* Targa doesn't have a mapped grayscale format, so we will */ |
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175 | /* demap quantized gray output. Never emit a colormap. */ |
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176 | write_header(cinfo, dinfo, 0); |
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177 | if (cinfo->quantize_colors) |
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178 | dest->pub.put_pixel_rows = put_demapped_gray; |
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179 | else |
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180 | dest->pub.put_pixel_rows = put_gray_rows; |
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181 | } else if (cinfo->out_color_space == JCS_RGB) { |
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182 | if (cinfo->quantize_colors) { |
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183 | /* We only support 8-bit colormap indexes, so only 256 colors */ |
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184 | num_colors = cinfo->actual_number_of_colors; |
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185 | if (num_colors > 256) |
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186 | ERREXIT1(cinfo, JERR_TOO_MANY_COLORS, num_colors); |
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187 | write_header(cinfo, dinfo, num_colors); |
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188 | /* Write the colormap. Note Targa uses BGR byte order */ |
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189 | outfile = dest->pub.output_file; |
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190 | for (i = 0; i < num_colors; i++) { |
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191 | putc(GETJSAMPLE(cinfo->colormap[2][i]), outfile); |
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192 | putc(GETJSAMPLE(cinfo->colormap[1][i]), outfile); |
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193 | putc(GETJSAMPLE(cinfo->colormap[0][i]), outfile); |
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194 | } |
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195 | dest->pub.put_pixel_rows = put_gray_rows; |
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196 | } else { |
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197 | write_header(cinfo, dinfo, 0); |
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198 | dest->pub.put_pixel_rows = put_pixel_rows; |
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199 | } |
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200 | } else { |
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201 | ERREXIT(cinfo, JERR_TGA_COLORSPACE); |
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202 | } |
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203 | } |
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204 | |
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205 | |
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206 | /* |
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207 | * Finish up at the end of the file. |
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208 | */ |
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209 | |
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210 | METHODDEF(void) |
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211 | finish_output_tga (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo) |
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212 | { |
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213 | /* Make sure we wrote the output file OK */ |
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214 | fflush(dinfo->output_file); |
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215 | if (ferror(dinfo->output_file)) |
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216 | ERREXIT(cinfo, JERR_FILE_WRITE); |
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217 | } |
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218 | |
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219 | |
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220 | /* |
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221 | * The module selection routine for Targa format output. |
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222 | */ |
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223 | |
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224 | GLOBAL(djpeg_dest_ptr) |
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225 | jinit_write_targa (j_decompress_ptr cinfo) |
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226 | { |
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227 | tga_dest_ptr dest; |
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228 | |
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229 | /* Create module interface object, fill in method pointers */ |
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230 | dest = (tga_dest_ptr) |
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231 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
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232 | SIZEOF(tga_dest_struct)); |
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233 | dest->pub.start_output = start_output_tga; |
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234 | dest->pub.finish_output = finish_output_tga; |
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235 | |
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236 | /* Calculate output image dimensions so we can allocate space */ |
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237 | jpeg_calc_output_dimensions(cinfo); |
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238 | |
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239 | /* Create I/O buffer. Note we make this near on a PC. */ |
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240 | dest->buffer_width = cinfo->output_width * cinfo->output_components; |
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241 | dest->iobuffer = (char *) |
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242 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
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243 | (size_t) (dest->buffer_width * SIZEOF(char))); |
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244 | |
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245 | /* Create decompressor output buffer. */ |
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246 | dest->pub.buffer = (*cinfo->mem->alloc_sarray) |
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247 | ((j_common_ptr) cinfo, JPOOL_IMAGE, dest->buffer_width, (JDIMENSION) 1); |
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248 | dest->pub.buffer_height = 1; |
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249 | |
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250 | return (djpeg_dest_ptr) dest; |
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251 | } |
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252 | |
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253 | #endif /* TARGA_SUPPORTED */ |
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