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2296
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1
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2 /* pngread.c - read a PNG file
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3 *
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4 * Last changed in libpng 1.6.10 [March 6, 2014]
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5 * Copyright (c) 1998-2014 Glenn Randers-Pehrson
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6 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
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7 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
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8 *
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9 * This code is released under the libpng license.
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10 * For conditions of distribution and use, see the disclaimer
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11 * and license in png.h
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12 *
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13 * This file contains routines that an application calls directly to
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14 * read a PNG file or stream.
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15 */
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16
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17 #include "pngpriv.h"
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18 #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) && defined(PNG_STDIO_SUPPORTED)
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19 # include <errno.h>
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20 #endif
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21
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22 #ifdef PNG_READ_SUPPORTED
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23
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24 /* Create a PNG structure for reading, and allocate any memory needed. */
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25 PNG_FUNCTION(png_structp,PNGAPI
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26 png_create_read_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
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27 png_error_ptr error_fn, png_error_ptr warn_fn),PNG_ALLOCATED)
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28 {
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29 #ifndef PNG_USER_MEM_SUPPORTED
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30 png_structp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
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31 error_fn, warn_fn, NULL, NULL, NULL);
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32 #else
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33 return png_create_read_struct_2(user_png_ver, error_ptr, error_fn,
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34 warn_fn, NULL, NULL, NULL);
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35 }
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36
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37 /* Alternate create PNG structure for reading, and allocate any memory
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38 * needed.
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39 */
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40 PNG_FUNCTION(png_structp,PNGAPI
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41 png_create_read_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
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42 png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
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43 png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
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44 {
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45 png_structp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
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46 error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
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47 #endif /* PNG_USER_MEM_SUPPORTED */
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48
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49 if (png_ptr != NULL)
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50 {
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51 png_ptr->mode = PNG_IS_READ_STRUCT;
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52
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53 /* Added in libpng-1.6.0; this can be used to detect a read structure if
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54 * required (it will be zero in a write structure.)
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55 */
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56 # ifdef PNG_SEQUENTIAL_READ_SUPPORTED
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57 png_ptr->IDAT_read_size = PNG_IDAT_READ_SIZE;
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58 # endif
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59
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60 # ifdef PNG_BENIGN_READ_ERRORS_SUPPORTED
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61 png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;
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62
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63 /* In stable builds only warn if an application error can be completely
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64 * handled.
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65 */
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66 # if PNG_LIBPNG_BUILD_BASE_TYPE >= PNG_LIBPNG_BUILD_RC
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67 png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN;
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68 # endif
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69 # endif
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70
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71 /* TODO: delay this, it can be done in png_init_io (if the app doesn't
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72 * do it itself) avoiding setting the default function if it is not
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73 * required.
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74 */
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75 png_set_read_fn(png_ptr, NULL, NULL);
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76 }
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77
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78 return png_ptr;
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79 }
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80
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81
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82 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
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83 /* Read the information before the actual image data. This has been
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84 * changed in v0.90 to allow reading a file that already has the magic
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85 * bytes read from the stream. You can tell libpng how many bytes have
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86 * been read from the beginning of the stream (up to the maximum of 8)
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87 * via png_set_sig_bytes(), and we will only check the remaining bytes
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88 * here. The application can then have access to the signature bytes we
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89 * read if it is determined that this isn't a valid PNG file.
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90 */
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91 void PNGAPI
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92 png_read_info(png_structrp png_ptr, png_inforp info_ptr)
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93 {
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94 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
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95 int keep;
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96 #endif
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97
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98 png_debug(1, "in png_read_info");
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99
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100 if (png_ptr == NULL || info_ptr == NULL)
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101 return;
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102
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103 /* Read and check the PNG file signature. */
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104 png_read_sig(png_ptr, info_ptr);
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105
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106 for (;;)
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107 {
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108 png_uint_32 length = png_read_chunk_header(png_ptr);
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109 png_uint_32 chunk_name = png_ptr->chunk_name;
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110
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111 /* IDAT logic needs to happen here to simplify getting the two flags
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112 * right.
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113 */
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114 if (chunk_name == png_IDAT)
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115 {
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116 if (!(png_ptr->mode & PNG_HAVE_IHDR))
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117 png_chunk_error(png_ptr, "Missing IHDR before IDAT");
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118
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119 else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
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120 !(png_ptr->mode & PNG_HAVE_PLTE))
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121 png_chunk_error(png_ptr, "Missing PLTE before IDAT");
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122
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123 else if (png_ptr->mode & PNG_AFTER_IDAT)
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124 png_chunk_benign_error(png_ptr, "Too many IDATs found");
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125
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126 png_ptr->mode |= PNG_HAVE_IDAT;
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127 }
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128
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129 else if (png_ptr->mode & PNG_HAVE_IDAT)
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130 png_ptr->mode |= PNG_AFTER_IDAT;
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131
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132 /* This should be a binary subdivision search or a hash for
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133 * matching the chunk name rather than a linear search.
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134 */
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135 if (chunk_name == png_IHDR)
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136 png_handle_IHDR(png_ptr, info_ptr, length);
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137
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138 else if (chunk_name == png_IEND)
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139 png_handle_IEND(png_ptr, info_ptr, length);
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140
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141 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
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142 else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
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143 {
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144 png_handle_unknown(png_ptr, info_ptr, length, keep);
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145
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146 if (chunk_name == png_PLTE)
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147 png_ptr->mode |= PNG_HAVE_PLTE;
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148
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149 else if (chunk_name == png_IDAT)
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150 {
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151 png_ptr->idat_size = 0; /* It has been consumed */
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152 break;
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153 }
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154 }
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155 #endif
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156 else if (chunk_name == png_PLTE)
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157 png_handle_PLTE(png_ptr, info_ptr, length);
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158
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159 else if (chunk_name == png_IDAT)
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160 {
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161 png_ptr->idat_size = length;
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162 break;
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163 }
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164
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165 #ifdef PNG_READ_bKGD_SUPPORTED
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166 else if (chunk_name == png_bKGD)
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167 png_handle_bKGD(png_ptr, info_ptr, length);
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168 #endif
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169
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170 #ifdef PNG_READ_cHRM_SUPPORTED
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171 else if (chunk_name == png_cHRM)
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172 png_handle_cHRM(png_ptr, info_ptr, length);
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173 #endif
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174
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175 #ifdef PNG_READ_gAMA_SUPPORTED
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176 else if (chunk_name == png_gAMA)
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177 png_handle_gAMA(png_ptr, info_ptr, length);
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178 #endif
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179
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180 #ifdef PNG_READ_hIST_SUPPORTED
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181 else if (chunk_name == png_hIST)
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182 png_handle_hIST(png_ptr, info_ptr, length);
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183 #endif
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184
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185 #ifdef PNG_READ_oFFs_SUPPORTED
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186 else if (chunk_name == png_oFFs)
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187 png_handle_oFFs(png_ptr, info_ptr, length);
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188 #endif
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189
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190 #ifdef PNG_READ_pCAL_SUPPORTED
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191 else if (chunk_name == png_pCAL)
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192 png_handle_pCAL(png_ptr, info_ptr, length);
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193 #endif
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194
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195 #ifdef PNG_READ_sCAL_SUPPORTED
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196 else if (chunk_name == png_sCAL)
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197 png_handle_sCAL(png_ptr, info_ptr, length);
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198 #endif
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199
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200 #ifdef PNG_READ_pHYs_SUPPORTED
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201 else if (chunk_name == png_pHYs)
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202 png_handle_pHYs(png_ptr, info_ptr, length);
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203 #endif
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204
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205 #ifdef PNG_READ_sBIT_SUPPORTED
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206 else if (chunk_name == png_sBIT)
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207 png_handle_sBIT(png_ptr, info_ptr, length);
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208 #endif
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209
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210 #ifdef PNG_READ_sRGB_SUPPORTED
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211 else if (chunk_name == png_sRGB)
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212 png_handle_sRGB(png_ptr, info_ptr, length);
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213 #endif
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214
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215 #ifdef PNG_READ_iCCP_SUPPORTED
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216 else if (chunk_name == png_iCCP)
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217 png_handle_iCCP(png_ptr, info_ptr, length);
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218 #endif
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219
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220 #ifdef PNG_READ_sPLT_SUPPORTED
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221 else if (chunk_name == png_sPLT)
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222 png_handle_sPLT(png_ptr, info_ptr, length);
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223 #endif
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224
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225 #ifdef PNG_READ_tEXt_SUPPORTED
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226 else if (chunk_name == png_tEXt)
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227 png_handle_tEXt(png_ptr, info_ptr, length);
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228 #endif
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229
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230 #ifdef PNG_READ_tIME_SUPPORTED
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231 else if (chunk_name == png_tIME)
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232 png_handle_tIME(png_ptr, info_ptr, length);
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233 #endif
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234
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235 #ifdef PNG_READ_tRNS_SUPPORTED
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236 else if (chunk_name == png_tRNS)
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237 png_handle_tRNS(png_ptr, info_ptr, length);
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238 #endif
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239
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240 #ifdef PNG_READ_zTXt_SUPPORTED
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241 else if (chunk_name == png_zTXt)
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242 png_handle_zTXt(png_ptr, info_ptr, length);
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243 #endif
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244
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245 #ifdef PNG_READ_iTXt_SUPPORTED
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246 else if (chunk_name == png_iTXt)
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247 png_handle_iTXt(png_ptr, info_ptr, length);
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248 #endif
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249
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250 else
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251 png_handle_unknown(png_ptr, info_ptr, length,
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252 PNG_HANDLE_CHUNK_AS_DEFAULT);
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253 }
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254 }
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255 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
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256
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257 /* Optional call to update the users info_ptr structure */
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258 void PNGAPI
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259 png_read_update_info(png_structrp png_ptr, png_inforp info_ptr)
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260 {
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261 png_debug(1, "in png_read_update_info");
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262
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263 if (png_ptr != NULL)
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264 {
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265 if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
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266 {
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267 png_read_start_row(png_ptr);
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268
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269 # ifdef PNG_READ_TRANSFORMS_SUPPORTED
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270 png_read_transform_info(png_ptr, info_ptr);
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271 # else
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272 PNG_UNUSED(info_ptr)
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273 # endif
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274 }
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275
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276 /* New in 1.6.0 this avoids the bug of doing the initializations twice */
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277 else
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278 png_app_error(png_ptr,
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279 "png_read_update_info/png_start_read_image: duplicate call");
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280 }
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281 }
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282
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283 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
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284 /* Initialize palette, background, etc, after transformations
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285 * are set, but before any reading takes place. This allows
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286 * the user to obtain a gamma-corrected palette, for example.
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287 * If the user doesn't call this, we will do it ourselves.
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288 */
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289 void PNGAPI
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290 png_start_read_image(png_structrp png_ptr)
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291 {
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292 png_debug(1, "in png_start_read_image");
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293
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294 if (png_ptr != NULL)
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295 {
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296 if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
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297 png_read_start_row(png_ptr);
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298
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299 /* New in 1.6.0 this avoids the bug of doing the initializations twice */
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300 else
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301 png_app_error(png_ptr,
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302 "png_start_read_image/png_read_update_info: duplicate call");
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303 }
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304 }
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305 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
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306
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307 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
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308 #ifdef PNG_MNG_FEATURES_SUPPORTED
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309 /* Undoes intrapixel differencing,
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310 * NOTE: this is apparently only supported in the 'sequential' reader.
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311 */
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312 static void
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313 png_do_read_intrapixel(png_row_infop row_info, png_bytep row)
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314 {
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315 png_debug(1, "in png_do_read_intrapixel");
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316
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317 if (
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318 (row_info->color_type & PNG_COLOR_MASK_COLOR))
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319 {
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320 int bytes_per_pixel;
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321 png_uint_32 row_width = row_info->width;
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322
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323 if (row_info->bit_depth == 8)
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324 {
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325 png_bytep rp;
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326 png_uint_32 i;
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327
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328 if (row_info->color_type == PNG_COLOR_TYPE_RGB)
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329 bytes_per_pixel = 3;
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330
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331 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
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332 bytes_per_pixel = 4;
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333
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334 else
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335 return;
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336
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337 for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
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338 {
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339 *(rp) = (png_byte)((256 + *rp + *(rp + 1)) & 0xff);
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340 *(rp+2) = (png_byte)((256 + *(rp + 2) + *(rp + 1)) & 0xff);
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341 }
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342 }
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343 else if (row_info->bit_depth == 16)
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344 {
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345 png_bytep rp;
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346 png_uint_32 i;
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347
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348 if (row_info->color_type == PNG_COLOR_TYPE_RGB)
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349 bytes_per_pixel = 6;
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350
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351 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
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352 bytes_per_pixel = 8;
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353
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354 else
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355 return;
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356
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357 for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
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358 {
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359 png_uint_32 s0 = (*(rp ) << 8) | *(rp + 1);
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360 png_uint_32 s1 = (*(rp + 2) << 8) | *(rp + 3);
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361 png_uint_32 s2 = (*(rp + 4) << 8) | *(rp + 5);
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362 png_uint_32 red = (s0 + s1 + 65536) & 0xffff;
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363 png_uint_32 blue = (s2 + s1 + 65536) & 0xffff;
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364 *(rp ) = (png_byte)((red >> 8) & 0xff);
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365 *(rp + 1) = (png_byte)(red & 0xff);
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366 *(rp + 4) = (png_byte)((blue >> 8) & 0xff);
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367 *(rp + 5) = (png_byte)(blue & 0xff);
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368 }
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369 }
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370 }
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371 }
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372 #endif /* PNG_MNG_FEATURES_SUPPORTED */
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373
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374 void PNGAPI
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375 png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)
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376 {
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377 png_row_info row_info;
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378
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379 if (png_ptr == NULL)
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380 return;
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381
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382 png_debug2(1, "in png_read_row (row %lu, pass %d)",
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383 (unsigned long)png_ptr->row_number, png_ptr->pass);
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384
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385 /* png_read_start_row sets the information (in particular iwidth) for this
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386 * interlace pass.
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387 */
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388 if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
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389 png_read_start_row(png_ptr);
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390
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391 /* 1.5.6: row_info moved out of png_struct to a local here. */
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392 row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */
|
|
|
393 row_info.color_type = png_ptr->color_type;
|
|
|
394 row_info.bit_depth = png_ptr->bit_depth;
|
|
|
395 row_info.channels = png_ptr->channels;
|
|
|
396 row_info.pixel_depth = png_ptr->pixel_depth;
|
|
|
397 row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
|
|
|
398
|
|
|
399 if (png_ptr->row_number == 0 && png_ptr->pass == 0)
|
|
|
400 {
|
|
|
401 /* Check for transforms that have been set but were defined out */
|
|
|
402 #if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED)
|
|
|
403 if (png_ptr->transformations & PNG_INVERT_MONO)
|
|
|
404 png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined");
|
|
|
405 #endif
|
|
|
406
|
|
|
407 #if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED)
|
|
|
408 if (png_ptr->transformations & PNG_FILLER)
|
|
|
409 png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined");
|
|
|
410 #endif
|
|
|
411
|
|
|
412 #if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
|
|
|
413 !defined(PNG_READ_PACKSWAP_SUPPORTED)
|
|
|
414 if (png_ptr->transformations & PNG_PACKSWAP)
|
|
|
415 png_warning(png_ptr, "PNG_READ_PACKSWAP_SUPPORTED is not defined");
|
|
|
416 #endif
|
|
|
417
|
|
|
418 #if defined(PNG_WRITE_PACK_SUPPORTED) && !defined(PNG_READ_PACK_SUPPORTED)
|
|
|
419 if (png_ptr->transformations & PNG_PACK)
|
|
|
420 png_warning(png_ptr, "PNG_READ_PACK_SUPPORTED is not defined");
|
|
|
421 #endif
|
|
|
422
|
|
|
423 #if defined(PNG_WRITE_SHIFT_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED)
|
|
|
424 if (png_ptr->transformations & PNG_SHIFT)
|
|
|
425 png_warning(png_ptr, "PNG_READ_SHIFT_SUPPORTED is not defined");
|
|
|
426 #endif
|
|
|
427
|
|
|
428 #if defined(PNG_WRITE_BGR_SUPPORTED) && !defined(PNG_READ_BGR_SUPPORTED)
|
|
|
429 if (png_ptr->transformations & PNG_BGR)
|
|
|
430 png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined");
|
|
|
431 #endif
|
|
|
432
|
|
|
433 #if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED)
|
|
|
434 if (png_ptr->transformations & PNG_SWAP_BYTES)
|
|
|
435 png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined");
|
|
|
436 #endif
|
|
|
437 }
|
|
|
438
|
|
|
439 #ifdef PNG_READ_INTERLACING_SUPPORTED
|
|
|
440 /* If interlaced and we do not need a new row, combine row and return.
|
|
|
441 * Notice that the pixels we have from previous rows have been transformed
|
|
|
442 * already; we can only combine like with like (transformed or
|
|
|
443 * untransformed) and, because of the libpng API for interlaced images, this
|
|
|
444 * means we must transform before de-interlacing.
|
|
|
445 */
|
|
|
446 if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
|
|
|
447 {
|
|
|
448 switch (png_ptr->pass)
|
|
|
449 {
|
|
|
450 case 0:
|
|
|
451 if (png_ptr->row_number & 0x07)
|
|
|
452 {
|
|
|
453 if (dsp_row != NULL)
|
|
|
454 png_combine_row(png_ptr, dsp_row, 1/*display*/);
|
|
|
455 png_read_finish_row(png_ptr);
|
|
|
456 return;
|
|
|
457 }
|
|
|
458 break;
|
|
|
459
|
|
|
460 case 1:
|
|
|
461 if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
|
|
|
462 {
|
|
|
463 if (dsp_row != NULL)
|
|
|
464 png_combine_row(png_ptr, dsp_row, 1/*display*/);
|
|
|
465
|
|
|
466 png_read_finish_row(png_ptr);
|
|
|
467 return;
|
|
|
468 }
|
|
|
469 break;
|
|
|
470
|
|
|
471 case 2:
|
|
|
472 if ((png_ptr->row_number & 0x07) != 4)
|
|
|
473 {
|
|
|
474 if (dsp_row != NULL && (png_ptr->row_number & 4))
|
|
|
475 png_combine_row(png_ptr, dsp_row, 1/*display*/);
|
|
|
476
|
|
|
477 png_read_finish_row(png_ptr);
|
|
|
478 return;
|
|
|
479 }
|
|
|
480 break;
|
|
|
481
|
|
|
482 case 3:
|
|
|
483 if ((png_ptr->row_number & 3) || png_ptr->width < 3)
|
|
|
484 {
|
|
|
485 if (dsp_row != NULL)
|
|
|
486 png_combine_row(png_ptr, dsp_row, 1/*display*/);
|
|
|
487
|
|
|
488 png_read_finish_row(png_ptr);
|
|
|
489 return;
|
|
|
490 }
|
|
|
491 break;
|
|
|
492
|
|
|
493 case 4:
|
|
|
494 if ((png_ptr->row_number & 3) != 2)
|
|
|
495 {
|
|
|
496 if (dsp_row != NULL && (png_ptr->row_number & 2))
|
|
|
497 png_combine_row(png_ptr, dsp_row, 1/*display*/);
|
|
|
498
|
|
|
499 png_read_finish_row(png_ptr);
|
|
|
500 return;
|
|
|
501 }
|
|
|
502 break;
|
|
|
503
|
|
|
504 case 5:
|
|
|
505 if ((png_ptr->row_number & 1) || png_ptr->width < 2)
|
|
|
506 {
|
|
|
507 if (dsp_row != NULL)
|
|
|
508 png_combine_row(png_ptr, dsp_row, 1/*display*/);
|
|
|
509
|
|
|
510 png_read_finish_row(png_ptr);
|
|
|
511 return;
|
|
|
512 }
|
|
|
513 break;
|
|
|
514
|
|
|
515 default:
|
|
|
516 case 6:
|
|
|
517 if (!(png_ptr->row_number & 1))
|
|
|
518 {
|
|
|
519 png_read_finish_row(png_ptr);
|
|
|
520 return;
|
|
|
521 }
|
|
|
522 break;
|
|
|
523 }
|
|
|
524 }
|
|
|
525 #endif
|
|
|
526
|
|
|
527 if (!(png_ptr->mode & PNG_HAVE_IDAT))
|
|
|
528 png_error(png_ptr, "Invalid attempt to read row data");
|
|
|
529
|
|
|
530 /* Fill the row with IDAT data: */
|
|
|
531 png_read_IDAT_data(png_ptr, png_ptr->row_buf, row_info.rowbytes + 1);
|
|
|
532
|
|
|
533 if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE)
|
|
|
534 {
|
|
|
535 if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST)
|
|
|
536 png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1,
|
|
|
537 png_ptr->prev_row + 1, png_ptr->row_buf[0]);
|
|
|
538 else
|
|
|
539 png_error(png_ptr, "bad adaptive filter value");
|
|
|
540 }
|
|
|
541
|
|
|
542 /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before
|
|
|
543 * 1.5.6, while the buffer really is this big in current versions of libpng
|
|
|
544 * it may not be in the future, so this was changed just to copy the
|
|
|
545 * interlaced count:
|
|
|
546 */
|
|
|
547 memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);
|
|
|
548
|
|
|
549 #ifdef PNG_MNG_FEATURES_SUPPORTED
|
|
|
550 if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
|
|
|
551 (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
|
|
|
552 {
|
|
|
553 /* Intrapixel differencing */
|
|
|
554 png_do_read_intrapixel(&row_info, png_ptr->row_buf + 1);
|
|
|
555 }
|
|
|
556 #endif
|
|
|
557
|
|
|
558 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
|
|
|
559 if (png_ptr->transformations)
|
|
|
560 png_do_read_transformations(png_ptr, &row_info);
|
|
|
561 #endif
|
|
|
562
|
|
|
563 /* The transformed pixel depth should match the depth now in row_info. */
|
|
|
564 if (png_ptr->transformed_pixel_depth == 0)
|
|
|
565 {
|
|
|
566 png_ptr->transformed_pixel_depth = row_info.pixel_depth;
|
|
|
567 if (row_info.pixel_depth > png_ptr->maximum_pixel_depth)
|
|
|
568 png_error(png_ptr, "sequential row overflow");
|
|
|
569 }
|
|
|
570
|
|
|
571 else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth)
|
|
|
572 png_error(png_ptr, "internal sequential row size calculation error");
|
|
|
573
|
|
|
574 #ifdef PNG_READ_INTERLACING_SUPPORTED
|
|
|
575 /* Blow up interlaced rows to full size */
|
|
|
576 if (png_ptr->interlaced &&
|
|
|
577 (png_ptr->transformations & PNG_INTERLACE))
|
|
|
578 {
|
|
|
579 if (png_ptr->pass < 6)
|
|
|
580 png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
|
|
|
581 png_ptr->transformations);
|
|
|
582
|
|
|
583 if (dsp_row != NULL)
|
|
|
584 png_combine_row(png_ptr, dsp_row, 1/*display*/);
|
|
|
585
|
|
|
586 if (row != NULL)
|
|
|
587 png_combine_row(png_ptr, row, 0/*row*/);
|
|
|
588 }
|
|
|
589
|
|
|
590 else
|
|
|
591 #endif
|
|
|
592 {
|
|
|
593 if (row != NULL)
|
|
|
594 png_combine_row(png_ptr, row, -1/*ignored*/);
|
|
|
595
|
|
|
596 if (dsp_row != NULL)
|
|
|
597 png_combine_row(png_ptr, dsp_row, -1/*ignored*/);
|
|
|
598 }
|
|
|
599 png_read_finish_row(png_ptr);
|
|
|
600
|
|
|
601 if (png_ptr->read_row_fn != NULL)
|
|
|
602 (*(png_ptr->read_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
|
|
|
603
|
|
|
604 }
|
|
|
605 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
|
|
|
606
|
|
|
607 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
|
|
608 /* Read one or more rows of image data. If the image is interlaced,
|
|
|
609 * and png_set_interlace_handling() has been called, the rows need to
|
|
|
610 * contain the contents of the rows from the previous pass. If the
|
|
|
611 * image has alpha or transparency, and png_handle_alpha()[*] has been
|
|
|
612 * called, the rows contents must be initialized to the contents of the
|
|
|
613 * screen.
|
|
|
614 *
|
|
|
615 * "row" holds the actual image, and pixels are placed in it
|
|
|
616 * as they arrive. If the image is displayed after each pass, it will
|
|
|
617 * appear to "sparkle" in. "display_row" can be used to display a
|
|
|
618 * "chunky" progressive image, with finer detail added as it becomes
|
|
|
619 * available. If you do not want this "chunky" display, you may pass
|
|
|
620 * NULL for display_row. If you do not want the sparkle display, and
|
|
|
621 * you have not called png_handle_alpha(), you may pass NULL for rows.
|
|
|
622 * If you have called png_handle_alpha(), and the image has either an
|
|
|
623 * alpha channel or a transparency chunk, you must provide a buffer for
|
|
|
624 * rows. In this case, you do not have to provide a display_row buffer
|
|
|
625 * also, but you may. If the image is not interlaced, or if you have
|
|
|
626 * not called png_set_interlace_handling(), the display_row buffer will
|
|
|
627 * be ignored, so pass NULL to it.
|
|
|
628 *
|
|
|
629 * [*] png_handle_alpha() does not exist yet, as of this version of libpng
|
|
|
630 */
|
|
|
631
|
|
|
632 void PNGAPI
|
|
|
633 png_read_rows(png_structrp png_ptr, png_bytepp row,
|
|
|
634 png_bytepp display_row, png_uint_32 num_rows)
|
|
|
635 {
|
|
|
636 png_uint_32 i;
|
|
|
637 png_bytepp rp;
|
|
|
638 png_bytepp dp;
|
|
|
639
|
|
|
640 png_debug(1, "in png_read_rows");
|
|
|
641
|
|
|
642 if (png_ptr == NULL)
|
|
|
643 return;
|
|
|
644
|
|
|
645 rp = row;
|
|
|
646 dp = display_row;
|
|
|
647 if (rp != NULL && dp != NULL)
|
|
|
648 for (i = 0; i < num_rows; i++)
|
|
|
649 {
|
|
|
650 png_bytep rptr = *rp++;
|
|
|
651 png_bytep dptr = *dp++;
|
|
|
652
|
|
|
653 png_read_row(png_ptr, rptr, dptr);
|
|
|
654 }
|
|
|
655
|
|
|
656 else if (rp != NULL)
|
|
|
657 for (i = 0; i < num_rows; i++)
|
|
|
658 {
|
|
|
659 png_bytep rptr = *rp;
|
|
|
660 png_read_row(png_ptr, rptr, NULL);
|
|
|
661 rp++;
|
|
|
662 }
|
|
|
663
|
|
|
664 else if (dp != NULL)
|
|
|
665 for (i = 0; i < num_rows; i++)
|
|
|
666 {
|
|
|
667 png_bytep dptr = *dp;
|
|
|
668 png_read_row(png_ptr, NULL, dptr);
|
|
|
669 dp++;
|
|
|
670 }
|
|
|
671 }
|
|
|
672 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
|
|
|
673
|
|
|
674 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
|
|
675 /* Read the entire image. If the image has an alpha channel or a tRNS
|
|
|
676 * chunk, and you have called png_handle_alpha()[*], you will need to
|
|
|
677 * initialize the image to the current image that PNG will be overlaying.
|
|
|
678 * We set the num_rows again here, in case it was incorrectly set in
|
|
|
679 * png_read_start_row() by a call to png_read_update_info() or
|
|
|
680 * png_start_read_image() if png_set_interlace_handling() wasn't called
|
|
|
681 * prior to either of these functions like it should have been. You can
|
|
|
682 * only call this function once. If you desire to have an image for
|
|
|
683 * each pass of a interlaced image, use png_read_rows() instead.
|
|
|
684 *
|
|
|
685 * [*] png_handle_alpha() does not exist yet, as of this version of libpng
|
|
|
686 */
|
|
|
687 void PNGAPI
|
|
|
688 png_read_image(png_structrp png_ptr, png_bytepp image)
|
|
|
689 {
|
|
|
690 png_uint_32 i, image_height;
|
|
|
691 int pass, j;
|
|
|
692 png_bytepp rp;
|
|
|
693
|
|
|
694 png_debug(1, "in png_read_image");
|
|
|
695
|
|
|
696 if (png_ptr == NULL)
|
|
|
697 return;
|
|
|
698
|
|
|
699 #ifdef PNG_READ_INTERLACING_SUPPORTED
|
|
|
700 if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
|
|
|
701 {
|
|
|
702 pass = png_set_interlace_handling(png_ptr);
|
|
|
703 /* And make sure transforms are initialized. */
|
|
|
704 png_start_read_image(png_ptr);
|
|
|
705 }
|
|
|
706 else
|
|
|
707 {
|
|
|
708 if (png_ptr->interlaced && !(png_ptr->transformations & PNG_INTERLACE))
|
|
|
709 {
|
|
|
710 /* Caller called png_start_read_image or png_read_update_info without
|
|
|
711 * first turning on the PNG_INTERLACE transform. We can fix this here,
|
|
|
712 * but the caller should do it!
|
|
|
713 */
|
|
|
714 png_warning(png_ptr, "Interlace handling should be turned on when "
|
|
|
715 "using png_read_image");
|
|
|
716 /* Make sure this is set correctly */
|
|
|
717 png_ptr->num_rows = png_ptr->height;
|
|
|
718 }
|
|
|
719
|
|
|
720 /* Obtain the pass number, which also turns on the PNG_INTERLACE flag in
|
|
|
721 * the above error case.
|
|
|
722 */
|
|
|
723 pass = png_set_interlace_handling(png_ptr);
|
|
|
724 }
|
|
|
725 #else
|
|
|
726 if (png_ptr->interlaced)
|
|
|
727 png_error(png_ptr,
|
|
|
728 "Cannot read interlaced image -- interlace handler disabled");
|
|
|
729
|
|
|
730 pass = 1;
|
|
|
731 #endif
|
|
|
732
|
|
|
733 image_height=png_ptr->height;
|
|
|
734
|
|
|
735 for (j = 0; j < pass; j++)
|
|
|
736 {
|
|
|
737 rp = image;
|
|
|
738 for (i = 0; i < image_height; i++)
|
|
|
739 {
|
|
|
740 png_read_row(png_ptr, *rp, NULL);
|
|
|
741 rp++;
|
|
|
742 }
|
|
|
743 }
|
|
|
744 }
|
|
|
745 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
|
|
|
746
|
|
|
747 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
|
|
748 /* Read the end of the PNG file. Will not read past the end of the
|
|
|
749 * file, will verify the end is accurate, and will read any comments
|
|
|
750 * or time information at the end of the file, if info is not NULL.
|
|
|
751 */
|
|
|
752 void PNGAPI
|
|
|
753 png_read_end(png_structrp png_ptr, png_inforp info_ptr)
|
|
|
754 {
|
|
|
755 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
|
|
|
756 int keep;
|
|
|
757 #endif
|
|
|
758
|
|
|
759 png_debug(1, "in png_read_end");
|
|
|
760
|
|
|
761 if (png_ptr == NULL)
|
|
|
762 return;
|
|
|
763
|
|
|
764 /* If png_read_end is called in the middle of reading the rows there may
|
|
|
765 * still be pending IDAT data and an owned zstream. Deal with this here.
|
|
|
766 */
|
|
|
767 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
|
|
|
768 if (!png_chunk_unknown_handling(png_ptr, png_IDAT))
|
|
|
769 #endif
|
|
|
770 png_read_finish_IDAT(png_ptr);
|
|
|
771
|
|
|
772 #ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
|
|
|
773 /* Report invalid palette index; added at libng-1.5.10 */
|
|
|
774 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
|
|
|
775 png_ptr->num_palette_max > png_ptr->num_palette)
|
|
|
776 png_benign_error(png_ptr, "Read palette index exceeding num_palette");
|
|
|
777 #endif
|
|
|
778
|
|
|
779 do
|
|
|
780 {
|
|
|
781 png_uint_32 length = png_read_chunk_header(png_ptr);
|
|
|
782 png_uint_32 chunk_name = png_ptr->chunk_name;
|
|
|
783
|
|
|
784 if (chunk_name == png_IEND)
|
|
|
785 png_handle_IEND(png_ptr, info_ptr, length);
|
|
|
786
|
|
|
787 else if (chunk_name == png_IHDR)
|
|
|
788 png_handle_IHDR(png_ptr, info_ptr, length);
|
|
|
789
|
|
|
790 else if (info_ptr == NULL)
|
|
|
791 png_crc_finish(png_ptr, length);
|
|
|
792
|
|
|
793 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
|
|
|
794 else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
|
|
|
795 {
|
|
|
796 if (chunk_name == png_IDAT)
|
|
|
797 {
|
|
|
798 if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
|
|
|
799 png_benign_error(png_ptr, "Too many IDATs found");
|
|
|
800 }
|
|
|
801 png_handle_unknown(png_ptr, info_ptr, length, keep);
|
|
|
802 if (chunk_name == png_PLTE)
|
|
|
803 png_ptr->mode |= PNG_HAVE_PLTE;
|
|
|
804 }
|
|
|
805 #endif
|
|
|
806
|
|
|
807 else if (chunk_name == png_IDAT)
|
|
|
808 {
|
|
|
809 /* Zero length IDATs are legal after the last IDAT has been
|
|
|
810 * read, but not after other chunks have been read.
|
|
|
811 */
|
|
|
812 if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
|
|
|
813 png_benign_error(png_ptr, "Too many IDATs found");
|
|
|
814
|
|
|
815 png_crc_finish(png_ptr, length);
|
|
|
816 }
|
|
|
817 else if (chunk_name == png_PLTE)
|
|
|
818 png_handle_PLTE(png_ptr, info_ptr, length);
|
|
|
819
|
|
|
820 #ifdef PNG_READ_bKGD_SUPPORTED
|
|
|
821 else if (chunk_name == png_bKGD)
|
|
|
822 png_handle_bKGD(png_ptr, info_ptr, length);
|
|
|
823 #endif
|
|
|
824
|
|
|
825 #ifdef PNG_READ_cHRM_SUPPORTED
|
|
|
826 else if (chunk_name == png_cHRM)
|
|
|
827 png_handle_cHRM(png_ptr, info_ptr, length);
|
|
|
828 #endif
|
|
|
829
|
|
|
830 #ifdef PNG_READ_gAMA_SUPPORTED
|
|
|
831 else if (chunk_name == png_gAMA)
|
|
|
832 png_handle_gAMA(png_ptr, info_ptr, length);
|
|
|
833 #endif
|
|
|
834
|
|
|
835 #ifdef PNG_READ_hIST_SUPPORTED
|
|
|
836 else if (chunk_name == png_hIST)
|
|
|
837 png_handle_hIST(png_ptr, info_ptr, length);
|
|
|
838 #endif
|
|
|
839
|
|
|
840 #ifdef PNG_READ_oFFs_SUPPORTED
|
|
|
841 else if (chunk_name == png_oFFs)
|
|
|
842 png_handle_oFFs(png_ptr, info_ptr, length);
|
|
|
843 #endif
|
|
|
844
|
|
|
845 #ifdef PNG_READ_pCAL_SUPPORTED
|
|
|
846 else if (chunk_name == png_pCAL)
|
|
|
847 png_handle_pCAL(png_ptr, info_ptr, length);
|
|
|
848 #endif
|
|
|
849
|
|
|
850 #ifdef PNG_READ_sCAL_SUPPORTED
|
|
|
851 else if (chunk_name == png_sCAL)
|
|
|
852 png_handle_sCAL(png_ptr, info_ptr, length);
|
|
|
853 #endif
|
|
|
854
|
|
|
855 #ifdef PNG_READ_pHYs_SUPPORTED
|
|
|
856 else if (chunk_name == png_pHYs)
|
|
|
857 png_handle_pHYs(png_ptr, info_ptr, length);
|
|
|
858 #endif
|
|
|
859
|
|
|
860 #ifdef PNG_READ_sBIT_SUPPORTED
|
|
|
861 else if (chunk_name == png_sBIT)
|
|
|
862 png_handle_sBIT(png_ptr, info_ptr, length);
|
|
|
863 #endif
|
|
|
864
|
|
|
865 #ifdef PNG_READ_sRGB_SUPPORTED
|
|
|
866 else if (chunk_name == png_sRGB)
|
|
|
867 png_handle_sRGB(png_ptr, info_ptr, length);
|
|
|
868 #endif
|
|
|
869
|
|
|
870 #ifdef PNG_READ_iCCP_SUPPORTED
|
|
|
871 else if (chunk_name == png_iCCP)
|
|
|
872 png_handle_iCCP(png_ptr, info_ptr, length);
|
|
|
873 #endif
|
|
|
874
|
|
|
875 #ifdef PNG_READ_sPLT_SUPPORTED
|
|
|
876 else if (chunk_name == png_sPLT)
|
|
|
877 png_handle_sPLT(png_ptr, info_ptr, length);
|
|
|
878 #endif
|
|
|
879
|
|
|
880 #ifdef PNG_READ_tEXt_SUPPORTED
|
|
|
881 else if (chunk_name == png_tEXt)
|
|
|
882 png_handle_tEXt(png_ptr, info_ptr, length);
|
|
|
883 #endif
|
|
|
884
|
|
|
885 #ifdef PNG_READ_tIME_SUPPORTED
|
|
|
886 else if (chunk_name == png_tIME)
|
|
|
887 png_handle_tIME(png_ptr, info_ptr, length);
|
|
|
888 #endif
|
|
|
889
|
|
|
890 #ifdef PNG_READ_tRNS_SUPPORTED
|
|
|
891 else if (chunk_name == png_tRNS)
|
|
|
892 png_handle_tRNS(png_ptr, info_ptr, length);
|
|
|
893 #endif
|
|
|
894
|
|
|
895 #ifdef PNG_READ_zTXt_SUPPORTED
|
|
|
896 else if (chunk_name == png_zTXt)
|
|
|
897 png_handle_zTXt(png_ptr, info_ptr, length);
|
|
|
898 #endif
|
|
|
899
|
|
|
900 #ifdef PNG_READ_iTXt_SUPPORTED
|
|
|
901 else if (chunk_name == png_iTXt)
|
|
|
902 png_handle_iTXt(png_ptr, info_ptr, length);
|
|
|
903 #endif
|
|
|
904
|
|
|
905 else
|
|
|
906 png_handle_unknown(png_ptr, info_ptr, length,
|
|
|
907 PNG_HANDLE_CHUNK_AS_DEFAULT);
|
|
|
908 } while (!(png_ptr->mode & PNG_HAVE_IEND));
|
|
|
909 }
|
|
|
910 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
|
|
|
911
|
|
|
912 /* Free all memory used in the read struct */
|
|
|
913 static void
|
|
|
914 png_read_destroy(png_structrp png_ptr)
|
|
|
915 {
|
|
|
916 png_debug(1, "in png_read_destroy");
|
|
|
917
|
|
|
918 #ifdef PNG_READ_GAMMA_SUPPORTED
|
|
|
919 png_destroy_gamma_table(png_ptr);
|
|
|
920 #endif
|
|
|
921
|
|
|
922 png_free(png_ptr, png_ptr->big_row_buf);
|
|
|
923 png_free(png_ptr, png_ptr->big_prev_row);
|
|
|
924 png_free(png_ptr, png_ptr->read_buffer);
|
|
|
925
|
|
|
926 #ifdef PNG_READ_QUANTIZE_SUPPORTED
|
|
|
927 png_free(png_ptr, png_ptr->palette_lookup);
|
|
|
928 png_free(png_ptr, png_ptr->quantize_index);
|
|
|
929 #endif
|
|
|
930
|
|
|
931 if (png_ptr->free_me & PNG_FREE_PLTE)
|
|
|
932 png_zfree(png_ptr, png_ptr->palette);
|
|
|
933 png_ptr->free_me &= ~PNG_FREE_PLTE;
|
|
|
934
|
|
|
935 #if defined(PNG_tRNS_SUPPORTED) || \
|
|
|
936 defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
|
|
|
937 if (png_ptr->free_me & PNG_FREE_TRNS)
|
|
|
938 png_free(png_ptr, png_ptr->trans_alpha);
|
|
|
939 png_ptr->free_me &= ~PNG_FREE_TRNS;
|
|
|
940 #endif
|
|
|
941
|
|
|
942 inflateEnd(&png_ptr->zstream);
|
|
|
943
|
|
|
944 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
|
|
|
945 png_free(png_ptr, png_ptr->save_buffer);
|
|
|
946 #endif
|
|
|
947
|
|
|
948 #if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) &&\
|
|
|
949 defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
|
|
|
950 png_free(png_ptr, png_ptr->unknown_chunk.data);
|
|
|
951 #endif
|
|
|
952
|
|
|
953 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
|
|
|
954 png_free(png_ptr, png_ptr->chunk_list);
|
|
|
955 #endif
|
|
|
956
|
|
|
957 /* NOTE: the 'setjmp' buffer may still be allocated and the memory and error
|
|
|
958 * callbacks are still set at this point. They are required to complete the
|
|
|
959 * destruction of the png_struct itself.
|
|
|
960 */
|
|
|
961 }
|
|
|
962
|
|
|
963 /* Free all memory used by the read */
|
|
|
964 void PNGAPI
|
|
|
965 png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr,
|
|
|
966 png_infopp end_info_ptr_ptr)
|
|
|
967 {
|
|
|
968 png_structrp png_ptr = NULL;
|
|
|
969
|
|
|
970 png_debug(1, "in png_destroy_read_struct");
|
|
|
971
|
|
|
972 if (png_ptr_ptr != NULL)
|
|
|
973 png_ptr = *png_ptr_ptr;
|
|
|
974
|
|
|
975 if (png_ptr == NULL)
|
|
|
976 return;
|
|
|
977
|
|
|
978 /* libpng 1.6.0: use the API to destroy info structs to ensure consistent
|
|
|
979 * behavior. Prior to 1.6.0 libpng did extra 'info' destruction in this API.
|
|
|
980 * The extra was, apparently, unnecessary yet this hides memory leak bugs.
|
|
|
981 */
|
|
|
982 png_destroy_info_struct(png_ptr, end_info_ptr_ptr);
|
|
|
983 png_destroy_info_struct(png_ptr, info_ptr_ptr);
|
|
|
984
|
|
|
985 *png_ptr_ptr = NULL;
|
|
|
986 png_read_destroy(png_ptr);
|
|
|
987 png_destroy_png_struct(png_ptr);
|
|
|
988 }
|
|
|
989
|
|
|
990 void PNGAPI
|
|
|
991 png_set_read_status_fn(png_structrp png_ptr, png_read_status_ptr read_row_fn)
|
|
|
992 {
|
|
|
993 if (png_ptr == NULL)
|
|
|
994 return;
|
|
|
995
|
|
|
996 png_ptr->read_row_fn = read_row_fn;
|
|
|
997 }
|
|
|
998
|
|
|
999
|
|
|
1000 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
|
|
1001 #ifdef PNG_INFO_IMAGE_SUPPORTED
|
|
|
1002 void PNGAPI
|
|
|
1003 png_read_png(png_structrp png_ptr, png_inforp info_ptr,
|
|
|
1004 int transforms,
|
|
|
1005 voidp params)
|
|
|
1006 {
|
|
|
1007 if (png_ptr == NULL || info_ptr == NULL)
|
|
|
1008 return;
|
|
|
1009
|
|
|
1010 /* png_read_info() gives us all of the information from the
|
|
|
1011 * PNG file before the first IDAT (image data chunk).
|
|
|
1012 */
|
|
|
1013 png_read_info(png_ptr, info_ptr);
|
|
|
1014 if (info_ptr->height > PNG_UINT_32_MAX/(sizeof (png_bytep)))
|
|
|
1015 png_error(png_ptr, "Image is too high to process with png_read_png()");
|
|
|
1016
|
|
|
1017 /* -------------- image transformations start here ------------------- */
|
|
|
1018 /* libpng 1.6.10: add code to cause a png_app_error if a selected TRANSFORM
|
|
|
1019 * is not implemented. This will only happen in de-configured (non-default)
|
|
|
1020 * libpng builds. The results can be unexpected - png_read_png may return
|
|
|
1021 * short or mal-formed rows because the transform is skipped.
|
|
|
1022 */
|
|
|
1023
|
|
|
1024 /* Tell libpng to strip 16-bit/color files down to 8 bits per color.
|
|
|
1025 */
|
|
|
1026 if (transforms & PNG_TRANSFORM_SCALE_16)
|
|
|
1027 /* Added at libpng-1.5.4. "strip_16" produces the same result that it
|
|
|
1028 * did in earlier versions, while "scale_16" is now more accurate.
|
|
|
1029 */
|
|
|
1030 #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
|
|
|
1031 png_set_scale_16(png_ptr);
|
|
|
1032 #else
|
|
|
1033 png_app_error(png_ptr, "PNG_TRANSFORM_SCALE_16 not supported");
|
|
|
1034 #endif
|
|
|
1035
|
|
|
1036 /* If both SCALE and STRIP are required pngrtran will effectively cancel the
|
|
|
1037 * latter by doing SCALE first. This is ok and allows apps not to check for
|
|
|
1038 * which is supported to get the right answer.
|
|
|
1039 */
|
|
|
1040 if (transforms & PNG_TRANSFORM_STRIP_16)
|
|
|
1041 #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
|
|
|
1042 png_set_strip_16(png_ptr);
|
|
|
1043 #else
|
|
|
1044 png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_16 not supported");
|
|
|
1045 #endif
|
|
|
1046
|
|
|
1047 /* Strip alpha bytes from the input data without combining with
|
|
|
1048 * the background (not recommended).
|
|
|
1049 */
|
|
|
1050 if (transforms & PNG_TRANSFORM_STRIP_ALPHA)
|
|
|
1051 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
|
|
|
1052 png_set_strip_alpha(png_ptr);
|
|
|
1053 #else
|
|
|
1054 png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_ALPHA not supported");
|
|
|
1055 #endif
|
|
|
1056
|
|
|
1057 /* Extract multiple pixels with bit depths of 1, 2, or 4 from a single
|
|
|
1058 * byte into separate bytes (useful for paletted and grayscale images).
|
|
|
1059 */
|
|
|
1060 if (transforms & PNG_TRANSFORM_PACKING)
|
|
|
1061 #ifdef PNG_READ_PACK_SUPPORTED
|
|
|
1062 png_set_packing(png_ptr);
|
|
|
1063 #else
|
|
|
1064 png_app_error(png_ptr, "PNG_TRANSFORM_PACKING not supported");
|
|
|
1065 #endif
|
|
|
1066
|
|
|
1067 /* Change the order of packed pixels to least significant bit first
|
|
|
1068 * (not useful if you are using png_set_packing).
|
|
|
1069 */
|
|
|
1070 if (transforms & PNG_TRANSFORM_PACKSWAP)
|
|
|
1071 #ifdef PNG_READ_PACKSWAP_SUPPORTED
|
|
|
1072 png_set_packswap(png_ptr);
|
|
|
1073 #else
|
|
|
1074 png_app_error(png_ptr, "PNG_TRANSFORM_PACKSWAP not supported");
|
|
|
1075 #endif
|
|
|
1076
|
|
|
1077 /* Expand paletted colors into true RGB triplets
|
|
|
1078 * Expand grayscale images to full 8 bits from 1, 2, or 4 bits/pixel
|
|
|
1079 * Expand paletted or RGB images with transparency to full alpha
|
|
|
1080 * channels so the data will be available as RGBA quartets.
|
|
|
1081 */
|
|
|
1082 if (transforms & PNG_TRANSFORM_EXPAND)
|
|
|
1083 #ifdef PNG_READ_EXPAND_SUPPORTED
|
|
|
1084 png_set_expand(png_ptr);
|
|
|
1085 #else
|
|
|
1086 png_app_error(png_ptr, "PNG_TRANSFORM_EXPAND not supported");
|
|
|
1087 #endif
|
|
|
1088
|
|
|
1089 /* We don't handle background color or gamma transformation or quantizing.
|
|
|
1090 */
|
|
|
1091
|
|
|
1092 /* Invert monochrome files to have 0 as white and 1 as black
|
|
|
1093 */
|
|
|
1094 if (transforms & PNG_TRANSFORM_INVERT_MONO)
|
|
|
1095 #ifdef PNG_READ_INVERT_SUPPORTED
|
|
|
1096 png_set_invert_mono(png_ptr);
|
|
|
1097 #else
|
|
|
1098 png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_MONO not supported");
|
|
|
1099 #endif
|
|
|
1100
|
|
|
1101 /* If you want to shift the pixel values from the range [0,255] or
|
|
|
1102 * [0,65535] to the original [0,7] or [0,31], or whatever range the
|
|
|
1103 * colors were originally in:
|
|
|
1104 */
|
|
|
1105 if (transforms & PNG_TRANSFORM_SHIFT)
|
|
|
1106 #ifdef PNG_READ_SHIFT_SUPPORTED
|
|
|
1107 if (info_ptr->valid & PNG_INFO_sBIT)
|
|
|
1108 png_set_shift(png_ptr, &info_ptr->sig_bit);
|
|
|
1109 #else
|
|
|
1110 png_app_error(png_ptr, "PNG_TRANSFORM_SHIFT not supported");
|
|
|
1111 #endif
|
|
|
1112
|
|
|
1113 /* Flip the RGB pixels to BGR (or RGBA to BGRA) */
|
|
|
1114 if (transforms & PNG_TRANSFORM_BGR)
|
|
|
1115 #ifdef PNG_READ_BGR_SUPPORTED
|
|
|
1116 png_set_bgr(png_ptr);
|
|
|
1117 #else
|
|
|
1118 png_app_error(png_ptr, "PNG_TRANSFORM_BGR not supported");
|
|
|
1119 #endif
|
|
|
1120
|
|
|
1121 /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */
|
|
|
1122 if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
|
|
|
1123 #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
|
|
|
1124 png_set_swap_alpha(png_ptr);
|
|
|
1125 #else
|
|
|
1126 png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ALPHA not supported");
|
|
|
1127 #endif
|
|
|
1128
|
|
|
1129 /* Swap bytes of 16-bit files to least significant byte first */
|
|
|
1130 if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
|
|
|
1131 #ifdef PNG_READ_SWAP_SUPPORTED
|
|
|
1132 png_set_swap(png_ptr);
|
|
|
1133 #else
|
|
|
1134 png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ENDIAN not supported");
|
|
|
1135 #endif
|
|
|
1136
|
|
|
1137 /* Added at libpng-1.2.41 */
|
|
|
1138 /* Invert the alpha channel from opacity to transparency */
|
|
|
1139 if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
|
|
|
1140 #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
|
|
|
1141 png_set_invert_alpha(png_ptr);
|
|
|
1142 #else
|
|
|
1143 png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_ALPHA not supported");
|
|
|
1144 #endif
|
|
|
1145
|
|
|
1146 /* Added at libpng-1.2.41 */
|
|
|
1147 /* Expand grayscale image to RGB */
|
|
|
1148 if (transforms & PNG_TRANSFORM_GRAY_TO_RGB)
|
|
|
1149 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
|
|
|
1150 png_set_gray_to_rgb(png_ptr);
|
|
|
1151 #else
|
|
|
1152 png_app_error(png_ptr, "PNG_TRANSFORM_GRAY_TO_RGB not supported");
|
|
|
1153 #endif
|
|
|
1154
|
|
|
1155 /* Added at libpng-1.5.4 */
|
|
|
1156 if (transforms & PNG_TRANSFORM_EXPAND_16)
|
|
|
1157 #ifdef PNG_READ_EXPAND_16_SUPPORTED
|
|
|
1158 png_set_expand_16(png_ptr);
|
|
|
1159 #else
|
|
|
1160 png_app_error(png_ptr, "PNG_TRANSFORM_EXPAND_16 not supported");
|
|
|
1161 #endif
|
|
|
1162
|
|
|
1163 /* We don't handle adding filler bytes */
|
|
|
1164
|
|
|
1165 /* We use png_read_image and rely on that for interlace handling, but we also
|
|
|
1166 * call png_read_update_info therefore must turn on interlace handling now:
|
|
|
1167 */
|
|
|
1168 (void)png_set_interlace_handling(png_ptr);
|
|
|
1169
|
|
|
1170 /* Optional call to gamma correct and add the background to the palette
|
|
|
1171 * and update info structure. REQUIRED if you are expecting libpng to
|
|
|
1172 * update the palette for you (i.e., you selected such a transform above).
|
|
|
1173 */
|
|
|
1174 png_read_update_info(png_ptr, info_ptr);
|
|
|
1175
|
|
|
1176 /* -------------- image transformations end here ------------------- */
|
|
|
1177
|
|
|
1178 png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
|
|
|
1179 if (info_ptr->row_pointers == NULL)
|
|
|
1180 {
|
|
|
1181 png_uint_32 iptr;
|
|
|
1182
|
|
|
1183 info_ptr->row_pointers = png_voidcast(png_bytepp, png_malloc(png_ptr,
|
|
|
1184 info_ptr->height * (sizeof (png_bytep))));
|
|
|
1185
|
|
|
1186 for (iptr=0; iptr<info_ptr->height; iptr++)
|
|
|
1187 info_ptr->row_pointers[iptr] = NULL;
|
|
|
1188
|
|
|
1189 info_ptr->free_me |= PNG_FREE_ROWS;
|
|
|
1190
|
|
|
1191 for (iptr = 0; iptr < info_ptr->height; iptr++)
|
|
|
1192 info_ptr->row_pointers[iptr] = png_voidcast(png_bytep,
|
|
|
1193 png_malloc(png_ptr, info_ptr->rowbytes));
|
|
|
1194 }
|
|
|
1195
|
|
|
1196 png_read_image(png_ptr, info_ptr->row_pointers);
|
|
|
1197 info_ptr->valid |= PNG_INFO_IDAT;
|
|
|
1198
|
|
|
1199 /* Read rest of file, and get additional chunks in info_ptr - REQUIRED */
|
|
|
1200 png_read_end(png_ptr, info_ptr);
|
|
|
1201
|
|
|
1202 PNG_UNUSED(params)
|
|
|
1203 }
|
|
|
1204 #endif /* PNG_INFO_IMAGE_SUPPORTED */
|
|
|
1205 #endif /* PNG_SEQUENTIAL_READ_SUPPORTED */
|
|
|
1206
|
|
|
1207 #ifdef PNG_SIMPLIFIED_READ_SUPPORTED
|
|
|
1208 /* SIMPLIFIED READ
|
|
|
1209 *
|
|
|
1210 * This code currently relies on the sequential reader, though it could easily
|
|
|
1211 * be made to work with the progressive one.
|
|
|
1212 */
|
|
|
1213 /* Arguments to png_image_finish_read: */
|
|
|
1214
|
|
|
1215 /* Encoding of PNG data (used by the color-map code) */
|
|
|
1216 # define P_NOTSET 0 /* File encoding not yet known */
|
|
|
1217 # define P_sRGB 1 /* 8-bit encoded to sRGB gamma */
|
|
|
1218 # define P_LINEAR 2 /* 16-bit linear: not encoded, NOT pre-multiplied! */
|
|
|
1219 # define P_FILE 3 /* 8-bit encoded to file gamma, not sRGB or linear */
|
|
|
1220 # define P_LINEAR8 4 /* 8-bit linear: only from a file value */
|
|
|
1221
|
|
|
1222 /* Color-map processing: after libpng has run on the PNG image further
|
|
|
1223 * processing may be needed to conver the data to color-map indicies.
|
|
|
1224 */
|
|
|
1225 #define PNG_CMAP_NONE 0
|
|
|
1226 #define PNG_CMAP_GA 1 /* Process GA data to a color-map with alpha */
|
|
|
1227 #define PNG_CMAP_TRANS 2 /* Process GA data to a background index */
|
|
|
1228 #define PNG_CMAP_RGB 3 /* Process RGB data */
|
|
|
1229 #define PNG_CMAP_RGB_ALPHA 4 /* Process RGBA data */
|
|
|
1230
|
|
|
1231 /* The following document where the background is for each processing case. */
|
|
|
1232 #define PNG_CMAP_NONE_BACKGROUND 256
|
|
|
1233 #define PNG_CMAP_GA_BACKGROUND 231
|
|
|
1234 #define PNG_CMAP_TRANS_BACKGROUND 254
|
|
|
1235 #define PNG_CMAP_RGB_BACKGROUND 256
|
|
|
1236 #define PNG_CMAP_RGB_ALPHA_BACKGROUND 216
|
|
|
1237
|
|
|
1238 typedef struct
|
|
|
1239 {
|
|
|
1240 /* Arguments: */
|
|
|
1241 png_imagep image;
|
|
|
1242 png_voidp buffer;
|
|
|
1243 png_int_32 row_stride;
|
|
|
1244 png_voidp colormap;
|
|
|
1245 png_const_colorp background;
|
|
|
1246 /* Local variables: */
|
|
|
1247 png_voidp local_row;
|
|
|
1248 png_voidp first_row;
|
|
|
1249 ptrdiff_t row_bytes; /* step between rows */
|
|
|
1250 int file_encoding; /* E_ values above */
|
|
|
1251 png_fixed_point gamma_to_linear; /* For P_FILE, reciprocal of gamma */
|
|
|
1252 int colormap_processing; /* PNG_CMAP_ values above */
|
|
|
1253 } png_image_read_control;
|
|
|
1254
|
|
|
1255 /* Do all the *safe* initialization - 'safe' means that png_error won't be
|
|
|
1256 * called, so setting up the jmp_buf is not required. This means that anything
|
|
|
1257 * called from here must *not* call png_malloc - it has to call png_malloc_warn
|
|
|
1258 * instead so that control is returned safely back to this routine.
|
|
|
1259 */
|
|
|
1260 static int
|
|
|
1261 png_image_read_init(png_imagep image)
|
|
|
1262 {
|
|
|
1263 if (image->opaque == NULL)
|
|
|
1264 {
|
|
|
1265 png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, image,
|
|
|
1266 png_safe_error, png_safe_warning);
|
|
|
1267
|
|
|
1268 /* And set the rest of the structure to NULL to ensure that the various
|
|
|
1269 * fields are consistent.
|
|
|
1270 */
|
|
|
1271 memset(image, 0, (sizeof *image));
|
|
|
1272 image->version = PNG_IMAGE_VERSION;
|
|
|
1273
|
|
|
1274 if (png_ptr != NULL)
|
|
|
1275 {
|
|
|
1276 png_infop info_ptr = png_create_info_struct(png_ptr);
|
|
|
1277
|
|
|
1278 if (info_ptr != NULL)
|
|
|
1279 {
|
|
|
1280 png_controlp control = png_voidcast(png_controlp,
|
|
|
1281 png_malloc_warn(png_ptr, (sizeof *control)));
|
|
|
1282
|
|
|
1283 if (control != NULL)
|
|
|
1284 {
|
|
|
1285 memset(control, 0, (sizeof *control));
|
|
|
1286
|
|
|
1287 control->png_ptr = png_ptr;
|
|
|
1288 control->info_ptr = info_ptr;
|
|
|
1289 control->for_write = 0;
|
|
|
1290
|
|
|
1291 image->opaque = control;
|
|
|
1292 return 1;
|
|
|
1293 }
|
|
|
1294
|
|
|
1295 /* Error clean up */
|
|
|
1296 png_destroy_info_struct(png_ptr, &info_ptr);
|
|
|
1297 }
|
|
|
1298
|
|
|
1299 png_destroy_read_struct(&png_ptr, NULL, NULL);
|
|
|
1300 }
|
|
|
1301
|
|
|
1302 return png_image_error(image, "png_image_read: out of memory");
|
|
|
1303 }
|
|
|
1304
|
|
|
1305 return png_image_error(image, "png_image_read: opaque pointer not NULL");
|
|
|
1306 }
|
|
|
1307
|
|
|
1308 /* Utility to find the base format of a PNG file from a png_struct. */
|
|
|
1309 static png_uint_32
|
|
|
1310 png_image_format(png_structrp png_ptr)
|
|
|
1311 {
|
|
|
1312 png_uint_32 format = 0;
|
|
|
1313
|
|
|
1314 if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
|
|
|
1315 format |= PNG_FORMAT_FLAG_COLOR;
|
|
|
1316
|
|
|
1317 if (png_ptr->color_type & PNG_COLOR_MASK_ALPHA)
|
|
|
1318 format |= PNG_FORMAT_FLAG_ALPHA;
|
|
|
1319
|
|
|
1320 /* Use png_ptr here, not info_ptr, because by examination png_handle_tRNS
|
|
|
1321 * sets the png_struct fields; that's all we are interested in here. The
|
|
|
1322 * precise interaction with an app call to png_set_tRNS and PNG file reading
|
|
|
1323 * is unclear.
|
|
|
1324 */
|
|
|
1325 else if (png_ptr->num_trans > 0)
|
|
|
1326 format |= PNG_FORMAT_FLAG_ALPHA;
|
|
|
1327
|
|
|
1328 if (png_ptr->bit_depth == 16)
|
|
|
1329 format |= PNG_FORMAT_FLAG_LINEAR;
|
|
|
1330
|
|
|
1331 if (png_ptr->color_type & PNG_COLOR_MASK_PALETTE)
|
|
|
1332 format |= PNG_FORMAT_FLAG_COLORMAP;
|
|
|
1333
|
|
|
1334 return format;
|
|
|
1335 }
|
|
|
1336
|
|
|
1337 /* Is the given gamma significantly different from sRGB? The test is the same
|
|
|
1338 * one used in pngrtran.c when deciding whether to do gamma correction. The
|
|
|
1339 * arithmetic optimizes the division by using the fact that the inverse of the
|
|
|
1340 * file sRGB gamma is 2.2
|
|
|
1341 */
|
|
|
1342 static int
|
|
|
1343 png_gamma_not_sRGB(png_fixed_point g)
|
|
|
1344 {
|
|
|
1345 if (g < PNG_FP_1)
|
|
|
1346 {
|
|
|
1347 /* An uninitialized gamma is assumed to be sRGB for the simplified API. */
|
|
|
1348 if (g == 0)
|
|
|
1349 return 0;
|
|
|
1350
|
|
|
1351 return png_gamma_significant((g * 11 + 2)/5 /* i.e. *2.2, rounded */);
|
|
|
1352 }
|
|
|
1353
|
|
|
1354 return 1;
|
|
|
1355 }
|
|
|
1356
|
|
|
1357 /* Do the main body of a 'png_image_begin_read' function; read the PNG file
|
|
|
1358 * header and fill in all the information. This is executed in a safe context,
|
|
|
1359 * unlike the init routine above.
|
|
|
1360 */
|
|
|
1361 static int
|
|
|
1362 png_image_read_header(png_voidp argument)
|
|
|
1363 {
|
|
|
1364 png_imagep image = png_voidcast(png_imagep, argument);
|
|
|
1365 png_structrp png_ptr = image->opaque->png_ptr;
|
|
|
1366 png_inforp info_ptr = image->opaque->info_ptr;
|
|
|
1367
|
|
|
1368 png_set_benign_errors(png_ptr, 1/*warn*/);
|
|
|
1369 png_read_info(png_ptr, info_ptr);
|
|
|
1370
|
|
|
1371 /* Do this the fast way; just read directly out of png_struct. */
|
|
|
1372 image->width = png_ptr->width;
|
|
|
1373 image->height = png_ptr->height;
|
|
|
1374
|
|
|
1375 {
|
|
|
1376 png_uint_32 format = png_image_format(png_ptr);
|
|
|
1377
|
|
|
1378 image->format = format;
|
|
|
1379
|
|
|
1380 #ifdef PNG_COLORSPACE_SUPPORTED
|
|
|
1381 /* Does the colorspace match sRGB? If there is no color endpoint
|
|
|
1382 * (colorant) information assume yes, otherwise require the
|
|
|
1383 * 'ENDPOINTS_MATCHP_sRGB' colorspace flag to have been set. If the
|
|
|
1384 * colorspace has been determined to be invalid ignore it.
|
|
|
1385 */
|
|
|
1386 if ((format & PNG_FORMAT_FLAG_COLOR) != 0 && ((png_ptr->colorspace.flags
|
|
|
1387 & (PNG_COLORSPACE_HAVE_ENDPOINTS|PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB|
|
|
|
1388 PNG_COLORSPACE_INVALID)) == PNG_COLORSPACE_HAVE_ENDPOINTS))
|
|
|
1389 image->flags |= PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB;
|
|
|
1390 #endif
|
|
|
1391 }
|
|
|
1392
|
|
|
1393 /* We need the maximum number of entries regardless of the format the
|
|
|
1394 * application sets here.
|
|
|
1395 */
|
|
|
1396 {
|
|
|
1397 png_uint_32 cmap_entries;
|
|
|
1398
|
|
|
1399 switch (png_ptr->color_type)
|
|
|
1400 {
|
|
|
1401 case PNG_COLOR_TYPE_GRAY:
|
|
|
1402 cmap_entries = 1U << png_ptr->bit_depth;
|
|
|
1403 break;
|
|
|
1404
|
|
|
1405 case PNG_COLOR_TYPE_PALETTE:
|
|
|
1406 cmap_entries = png_ptr->num_palette;
|
|
|
1407 break;
|
|
|
1408
|
|
|
1409 default:
|
|
|
1410 cmap_entries = 256;
|
|
|
1411 break;
|
|
|
1412 }
|
|
|
1413
|
|
|
1414 if (cmap_entries > 256)
|
|
|
1415 cmap_entries = 256;
|
|
|
1416
|
|
|
1417 image->colormap_entries = cmap_entries;
|
|
|
1418 }
|
|
|
1419
|
|
|
1420 return 1;
|
|
|
1421 }
|
|
|
1422
|
|
|
1423 #ifdef PNG_STDIO_SUPPORTED
|
|
|
1424 int PNGAPI
|
|
|
1425 png_image_begin_read_from_stdio(png_imagep image, FILE* file)
|
|
|
1426 {
|
|
|
1427 if (image != NULL && image->version == PNG_IMAGE_VERSION)
|
|
|
1428 {
|
|
|
1429 if (file != NULL)
|
|
|
1430 {
|
|
|
1431 if (png_image_read_init(image))
|
|
|
1432 {
|
|
|
1433 /* This is slightly evil, but png_init_io doesn't do anything other
|
|
|
1434 * than this and we haven't changed the standard IO functions so
|
|
|
1435 * this saves a 'safe' function.
|
|
|
1436 */
|
|
|
1437 image->opaque->png_ptr->io_ptr = file;
|
|
|
1438 return png_safe_execute(image, png_image_read_header, image);
|
|
|
1439 }
|
|
|
1440 }
|
|
|
1441
|
|
|
1442 else
|
|
|
1443 return png_image_error(image,
|
|
|
1444 "png_image_begin_read_from_stdio: invalid argument");
|
|
|
1445 }
|
|
|
1446
|
|
|
1447 else if (image != NULL)
|
|
|
1448 return png_image_error(image,
|
|
|
1449 "png_image_begin_read_from_stdio: incorrect PNG_IMAGE_VERSION");
|
|
|
1450
|
|
|
1451 return 0;
|
|
|
1452 }
|
|
|
1453
|
|
|
1454 int PNGAPI
|
|
|
1455 png_image_begin_read_from_file(png_imagep image, const char *file_name)
|
|
|
1456 {
|
|
|
1457 if (image != NULL && image->version == PNG_IMAGE_VERSION)
|
|
|
1458 {
|
|
|
1459 if (file_name != NULL)
|
|
|
1460 {
|
|
|
1461 FILE *fp = fopen(file_name, "rb");
|
|
|
1462
|
|
|
1463 if (fp != NULL)
|
|
|
1464 {
|
|
|
1465 if (png_image_read_init(image))
|
|
|
1466 {
|
|
|
1467 image->opaque->png_ptr->io_ptr = fp;
|
|
|
1468 image->opaque->owned_file = 1;
|
|
|
1469 return png_safe_execute(image, png_image_read_header, image);
|
|
|
1470 }
|
|
|
1471
|
|
|
1472 /* Clean up: just the opened file. */
|
|
|
1473 (void)fclose(fp);
|
|
|
1474 }
|
|
|
1475
|
|
|
1476 else
|
|
|
1477 return png_image_error(image, strerror(errno));
|
|
|
1478 }
|
|
|
1479
|
|
|
1480 else
|
|
|
1481 return png_image_error(image,
|
|
|
1482 "png_image_begin_read_from_file: invalid argument");
|
|
|
1483 }
|
|
|
1484
|
|
|
1485 else if (image != NULL)
|
|
|
1486 return png_image_error(image,
|
|
|
1487 "png_image_begin_read_from_file: incorrect PNG_IMAGE_VERSION");
|
|
|
1488
|
|
|
1489 return 0;
|
|
|
1490 }
|
|
|
1491 #endif /* PNG_STDIO_SUPPORTED */
|
|
|
1492
|
|
|
1493 static void PNGCBAPI
|
|
|
1494 png_image_memory_read(png_structp png_ptr, png_bytep out, png_size_t need)
|
|
|
1495 {
|
|
|
1496 if (png_ptr != NULL)
|
|
|
1497 {
|
|
|
1498 png_imagep image = png_voidcast(png_imagep, png_ptr->io_ptr);
|
|
|
1499 if (image != NULL)
|
|
|
1500 {
|
|
|
1501 png_controlp cp = image->opaque;
|
|
|
1502 if (cp != NULL)
|
|
|
1503 {
|
|
|
1504 png_const_bytep memory = cp->memory;
|
|
|
1505 png_size_t size = cp->size;
|
|
|
1506
|
|
|
1507 if (memory != NULL && size >= need)
|
|
|
1508 {
|
|
|
1509 memcpy(out, memory, need);
|
|
|
1510 cp->memory = memory + need;
|
|
|
1511 cp->size = size - need;
|
|
|
1512 return;
|
|
|
1513 }
|
|
|
1514
|
|
|
1515 png_error(png_ptr, "read beyond end of data");
|
|
|
1516 }
|
|
|
1517 }
|
|
|
1518
|
|
|
1519 png_error(png_ptr, "invalid memory read");
|
|
|
1520 }
|
|
|
1521 }
|
|
|
1522
|
|
|
1523 int PNGAPI png_image_begin_read_from_memory(png_imagep image,
|
|
|
1524 png_const_voidp memory, png_size_t size)
|
|
|
1525 {
|
|
|
1526 if (image != NULL && image->version == PNG_IMAGE_VERSION)
|
|
|
1527 {
|
|
|
1528 if (memory != NULL && size > 0)
|
|
|
1529 {
|
|
|
1530 if (png_image_read_init(image))
|
|
|
1531 {
|
|
|
1532 /* Now set the IO functions to read from the memory buffer and
|
|
|
1533 * store it into io_ptr. Again do this in-place to avoid calling a
|
|
|
1534 * libpng function that requires error handling.
|
|
|
1535 */
|
|
|
1536 image->opaque->memory = png_voidcast(png_const_bytep, memory);
|
|
|
1537 image->opaque->size = size;
|
|
|
1538 image->opaque->png_ptr->io_ptr = image;
|
|
|
1539 image->opaque->png_ptr->read_data_fn = png_image_memory_read;
|
|
|
1540
|
|
|
1541 return png_safe_execute(image, png_image_read_header, image);
|
|
|
1542 }
|
|
|
1543 }
|
|
|
1544
|
|
|
1545 else
|
|
|
1546 return png_image_error(image,
|
|
|
1547 "png_image_begin_read_from_memory: invalid argument");
|
|
|
1548 }
|
|
|
1549
|
|
|
1550 else if (image != NULL)
|
|
|
1551 return png_image_error(image,
|
|
|
1552 "png_image_begin_read_from_memory: incorrect PNG_IMAGE_VERSION");
|
|
|
1553
|
|
|
1554 return 0;
|
|
|
1555 }
|
|
|
1556
|
|
|
1557 /* Utility function to skip chunks that are not used by the simplified image
|
|
|
1558 * read functions and an appropriate macro to call it.
|
|
|
1559 */
|
|
|
1560 #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
|
|
|
1561 static void
|
|
|
1562 png_image_skip_unused_chunks(png_structrp png_ptr)
|
|
|
1563 {
|
|
|
1564 /* Prepare the reader to ignore all recognized chunks whose data will not
|
|
|
1565 * be used, i.e., all chunks recognized by libpng except for those
|
|
|
1566 * involved in basic image reading:
|
|
|
1567 *
|
|
|
1568 * IHDR, PLTE, IDAT, IEND
|
|
|
1569 *
|
|
|
1570 * Or image data handling:
|
|
|
1571 *
|
|
|
1572 * tRNS, bKGD, gAMA, cHRM, sRGB, [iCCP] and sBIT.
|
|
|
1573 *
|
|
|
1574 * This provides a small performance improvement and eliminates any
|
|
|
1575 * potential vulnerability to security problems in the unused chunks.
|
|
|
1576 *
|
|
|
1577 * At present the iCCP chunk data isn't used, so iCCP chunk can be ignored
|
|
|
1578 * too. This allows the simplified API to be compiled without iCCP support,
|
|
|
1579 * however if the support is there the chunk is still checked to detect
|
|
|
1580 * errors (which are unfortunately quite common.)
|
|
|
1581 */
|
|
|
1582 {
|
|
|
1583 static PNG_CONST png_byte chunks_to_process[] = {
|
|
|
1584 98, 75, 71, 68, '\0', /* bKGD */
|
|
|
1585 99, 72, 82, 77, '\0', /* cHRM */
|
|
|
1586 103, 65, 77, 65, '\0', /* gAMA */
|
|
|
1587 # ifdef PNG_READ_iCCP_SUPPORTED
|
|
|
1588 105, 67, 67, 80, '\0', /* iCCP */
|
|
|
1589 # endif
|
|
|
1590 115, 66, 73, 84, '\0', /* sBIT */
|
|
|
1591 115, 82, 71, 66, '\0', /* sRGB */
|
|
|
1592 };
|
|
|
1593
|
|
|
1594 /* Ignore unknown chunks and all other chunks except for the
|
|
|
1595 * IHDR, PLTE, tRNS, IDAT, and IEND chunks.
|
|
|
1596 */
|
|
|
1597 png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_NEVER,
|
|
|
1598 NULL, -1);
|
|
|
1599
|
|
|
1600 /* But do not ignore image data handling chunks */
|
|
|
1601 png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_AS_DEFAULT,
|
|
|
1602 chunks_to_process, (sizeof chunks_to_process)/5);
|
|
|
1603 }
|
|
|
1604 }
|
|
|
1605
|
|
|
1606 # define PNG_SKIP_CHUNKS(p) png_image_skip_unused_chunks(p)
|
|
|
1607 #else
|
|
|
1608 # define PNG_SKIP_CHUNKS(p) ((void)0)
|
|
|
1609 #endif /* PNG_HANDLE_AS_UNKNOWN_SUPPORTED */
|
|
|
1610
|
|
|
1611 /* The following macro gives the exact rounded answer for all values in the
|
|
|
1612 * range 0..255 (it actually divides by 51.2, but the rounding still generates
|
|
|
1613 * the correct numbers 0..5
|
|
|
1614 */
|
|
|
1615 #define PNG_DIV51(v8) (((v8) * 5 + 130) >> 8)
|
|
|
1616
|
|
|
1617 /* Utility functions to make particular color-maps */
|
|
|
1618 static void
|
|
|
1619 set_file_encoding(png_image_read_control *display)
|
|
|
1620 {
|
|
|
1621 png_fixed_point g = display->image->opaque->png_ptr->colorspace.gamma;
|
|
|
1622 if (png_gamma_significant(g))
|
|
|
1623 {
|
|
|
1624 if (png_gamma_not_sRGB(g))
|
|
|
1625 {
|
|
|
1626 display->file_encoding = P_FILE;
|
|
|
1627 display->gamma_to_linear = png_reciprocal(g);
|
|
|
1628 }
|
|
|
1629
|
|
|
1630 else
|
|
|
1631 display->file_encoding = P_sRGB;
|
|
|
1632 }
|
|
|
1633
|
|
|
1634 else
|
|
|
1635 display->file_encoding = P_LINEAR8;
|
|
|
1636 }
|
|
|
1637
|
|
|
1638 static unsigned int
|
|
|
1639 decode_gamma(png_image_read_control *display, png_uint_32 value, int encoding)
|
|
|
1640 {
|
|
|
1641 if (encoding == P_FILE) /* double check */
|
|
|
1642 encoding = display->file_encoding;
|
|
|
1643
|
|
|
1644 if (encoding == P_NOTSET) /* must be the file encoding */
|
|
|
1645 {
|
|
|
1646 set_file_encoding(display);
|
|
|
1647 encoding = display->file_encoding;
|
|
|
1648 }
|
|
|
1649
|
|
|
1650 switch (encoding)
|
|
|
1651 {
|
|
|
1652 case P_FILE:
|
|
|
1653 value = png_gamma_16bit_correct(value*257, display->gamma_to_linear);
|
|
|
1654 break;
|
|
|
1655
|
|
|
1656 case P_sRGB:
|
|
|
1657 value = png_sRGB_table[value];
|
|
|
1658 break;
|
|
|
1659
|
|
|
1660 case P_LINEAR:
|
|
|
1661 break;
|
|
|
1662
|
|
|
1663 case P_LINEAR8:
|
|
|
1664 value *= 257;
|
|
|
1665 break;
|
|
|
1666
|
|
|
1667 default:
|
|
|
1668 png_error(display->image->opaque->png_ptr,
|
|
|
1669 "unexpected encoding (internal error)");
|
|
|
1670 break;
|
|
|
1671 }
|
|
|
1672
|
|
|
1673 return value;
|
|
|
1674 }
|
|
|
1675
|
|
|
1676 static png_uint_32
|
|
|
1677 png_colormap_compose(png_image_read_control *display,
|
|
|
1678 png_uint_32 foreground, int foreground_encoding, png_uint_32 alpha,
|
|
|
1679 png_uint_32 background, int encoding)
|
|
|
1680 {
|
|
|
1681 /* The file value is composed on the background, the background has the given
|
|
|
1682 * encoding and so does the result, the file is encoded with P_FILE and the
|
|
|
1683 * file and alpha are 8-bit values. The (output) encoding will always be
|
|
|
1684 * P_LINEAR or P_sRGB.
|
|
|
1685 */
|
|
|
1686 png_uint_32 f = decode_gamma(display, foreground, foreground_encoding);
|
|
|
1687 png_uint_32 b = decode_gamma(display, background, encoding);
|
|
|
1688
|
|
|
1689 /* The alpha is always an 8-bit value (it comes from the palette), the value
|
|
|
1690 * scaled by 255 is what PNG_sRGB_FROM_LINEAR requires.
|
|
|
1691 */
|
|
|
1692 f = f * alpha + b * (255-alpha);
|
|
|
1693
|
|
|
1694 if (encoding == P_LINEAR)
|
|
|
1695 {
|
|
|
1696 /* Scale to 65535; divide by 255, approximately (in fact this is extremely
|
|
|
1697 * accurate, it divides by 255.00000005937181414556, with no overflow.)
|
|
|
1698 */
|
|
|
1699 f *= 257; /* Now scaled by 65535 */
|
|
|
1700 f += f >> 16;
|
|
|
1701 f = (f+32768) >> 16;
|
|
|
1702 }
|
|
|
1703
|
|
|
1704 else /* P_sRGB */
|
|
|
1705 f = PNG_sRGB_FROM_LINEAR(f);
|
|
|
1706
|
|
|
1707 return f;
|
|
|
1708 }
|
|
|
1709
|
|
|
1710 /* NOTE: P_LINEAR values to this routine must be 16-bit, but P_FILE values must
|
|
|
1711 * be 8-bit.
|
|
|
1712 */
|
|
|
1713 static void
|
|
|
1714 png_create_colormap_entry(png_image_read_control *display,
|
|
|
1715 png_uint_32 ip, png_uint_32 red, png_uint_32 green, png_uint_32 blue,
|
|
|
1716 png_uint_32 alpha, int encoding)
|
|
|
1717 {
|
|
|
1718 png_imagep image = display->image;
|
|
|
1719 const int output_encoding = (image->format & PNG_FORMAT_FLAG_LINEAR) ?
|
|
|
1720 P_LINEAR : P_sRGB;
|
|
|
1721 const int convert_to_Y = (image->format & PNG_FORMAT_FLAG_COLOR) == 0 &&
|
|
|
1722 (red != green || green != blue);
|
|
|
1723
|
|
|
1724 if (ip > 255)
|
|
|
1725 png_error(image->opaque->png_ptr, "color-map index out of range");
|
|
|
1726
|
|
|
1727 /* Update the cache with whether the file gamma is significantly different
|
|
|
1728 * from sRGB.
|
|
|
1729 */
|
|
|
1730 if (encoding == P_FILE)
|
|
|
1731 {
|
|
|
1732 if (display->file_encoding == P_NOTSET)
|
|
|
1733 set_file_encoding(display);
|
|
|
1734
|
|
|
1735 /* Note that the cached value may be P_FILE too, but if it is then the
|
|
|
1736 * gamma_to_linear member has been set.
|
|
|
1737 */
|
|
|
1738 encoding = display->file_encoding;
|
|
|
1739 }
|
|
|
1740
|
|
|
1741 if (encoding == P_FILE)
|
|
|
1742 {
|
|
|
1743 png_fixed_point g = display->gamma_to_linear;
|
|
|
1744
|
|
|
1745 red = png_gamma_16bit_correct(red*257, g);
|
|
|
1746 green = png_gamma_16bit_correct(green*257, g);
|
|
|
1747 blue = png_gamma_16bit_correct(blue*257, g);
|
|
|
1748
|
|
|
1749 if (convert_to_Y || output_encoding == P_LINEAR)
|
|
|
1750 {
|
|
|
1751 alpha *= 257;
|
|
|
1752 encoding = P_LINEAR;
|
|
|
1753 }
|
|
|
1754
|
|
|
1755 else
|
|
|
1756 {
|
|
|
1757 red = PNG_sRGB_FROM_LINEAR(red * 255);
|
|
|
1758 green = PNG_sRGB_FROM_LINEAR(green * 255);
|
|
|
1759 blue = PNG_sRGB_FROM_LINEAR(blue * 255);
|
|
|
1760 encoding = P_sRGB;
|
|
|
1761 }
|
|
|
1762 }
|
|
|
1763
|
|
|
1764 else if (encoding == P_LINEAR8)
|
|
|
1765 {
|
|
|
1766 /* This encoding occurs quite frequently in test cases because PngSuite
|
|
|
1767 * includes a gAMA 1.0 chunk with most images.
|
|
|
1768 */
|
|
|
1769 red *= 257;
|
|
|
1770 green *= 257;
|
|
|
1771 blue *= 257;
|
|
|
1772 alpha *= 257;
|
|
|
1773 encoding = P_LINEAR;
|
|
|
1774 }
|
|
|
1775
|
|
|
1776 else if (encoding == P_sRGB && (convert_to_Y || output_encoding == P_LINEAR))
|
|
|
1777 {
|
|
|
1778 /* The values are 8-bit sRGB values, but must be converted to 16-bit
|
|
|
1779 * linear.
|
|
|
1780 */
|
|
|
1781 red = png_sRGB_table[red];
|
|
|
1782 green = png_sRGB_table[green];
|
|
|
1783 blue = png_sRGB_table[blue];
|
|
|
1784 alpha *= 257;
|
|
|
1785 encoding = P_LINEAR;
|
|
|
1786 }
|
|
|
1787
|
|
|
1788 /* This is set if the color isn't gray but the output is. */
|
|
|
1789 if (encoding == P_LINEAR)
|
|
|
1790 {
|
|
|
1791 if (convert_to_Y)
|
|
|
1792 {
|
|
|
1793 /* NOTE: these values are copied from png_do_rgb_to_gray */
|
|
|
1794 png_uint_32 y = (png_uint_32)6968 * red + (png_uint_32)23434 * green +
|
|
|
1795 (png_uint_32)2366 * blue;
|
|
|
1796
|
|
|
1797 if (output_encoding == P_LINEAR)
|
|
|
1798 y = (y + 16384) >> 15;
|
|
|
1799
|
|
|
1800 else
|
|
|
1801 {
|
|
|
1802 /* y is scaled by 32768, we need it scaled by 255: */
|
|
|
1803 y = (y + 128) >> 8;
|
|
|
1804 y *= 255;
|
|
|
1805 y = PNG_sRGB_FROM_LINEAR((y + 64) >> 7);
|
|
|
1806 encoding = P_sRGB;
|
|
|
1807 }
|
|
|
1808
|
|
|
1809 blue = red = green = y;
|
|
|
1810 }
|
|
|
1811
|
|
|
1812 else if (output_encoding == P_sRGB)
|
|
|
1813 {
|
|
|
1814 red = PNG_sRGB_FROM_LINEAR(red * 255);
|
|
|
1815 green = PNG_sRGB_FROM_LINEAR(green * 255);
|
|
|
1816 blue = PNG_sRGB_FROM_LINEAR(blue * 255);
|
|
|
1817 alpha = PNG_DIV257(alpha);
|
|
|
1818 encoding = P_sRGB;
|
|
|
1819 }
|
|
|
1820 }
|
|
|
1821
|
|
|
1822 if (encoding != output_encoding)
|
|
|
1823 png_error(image->opaque->png_ptr, "bad encoding (internal error)");
|
|
|
1824
|
|
|
1825 /* Store the value. */
|
|
|
1826 {
|
|
|
1827 # ifdef PNG_FORMAT_AFIRST_SUPPORTED
|
|
|
1828 const int afirst = (image->format & PNG_FORMAT_FLAG_AFIRST) != 0 &&
|
|
|
1829 (image->format & PNG_FORMAT_FLAG_ALPHA) != 0;
|
|
|
1830 # else
|
|
|
1831 # define afirst 0
|
|
|
1832 # endif
|
|
|
1833 # ifdef PNG_FORMAT_BGR_SUPPORTED
|
|
|
1834 const int bgr = (image->format & PNG_FORMAT_FLAG_BGR) ? 2 : 0;
|
|
|
1835 # else
|
|
|
1836 # define bgr 0
|
|
|
1837 # endif
|
|
|
1838
|
|
|
1839 if (output_encoding == P_LINEAR)
|
|
|
1840 {
|
|
|
1841 png_uint_16p entry = png_voidcast(png_uint_16p, display->colormap);
|
|
|
1842
|
|
|
1843 entry += ip * PNG_IMAGE_SAMPLE_CHANNELS(image->format);
|
|
|
1844
|
|
|
1845 /* The linear 16-bit values must be pre-multiplied by the alpha channel
|
|
|
1846 * value, if less than 65535 (this is, effectively, composite on black
|
|
|
1847 * if the alpha channel is removed.)
|
|
|
1848 */
|
|
|
1849 switch (PNG_IMAGE_SAMPLE_CHANNELS(image->format))
|
|
|
1850 {
|
|
|
1851 case 4:
|
|
|
1852 entry[afirst ? 0 : 3] = (png_uint_16)alpha;
|
|
|
1853 /* FALL THROUGH */
|
|
|
1854
|
|
|
1855 case 3:
|
|
|
1856 if (alpha < 65535)
|
|
|
1857 {
|
|
|
1858 if (alpha > 0)
|
|
|
1859 {
|
|
|
1860 blue = (blue * alpha + 32767U)/65535U;
|
|
|
1861 green = (green * alpha + 32767U)/65535U;
|
|
|
1862 red = (red * alpha + 32767U)/65535U;
|
|
|
1863 }
|
|
|
1864
|
|
|
1865 else
|
|
|
1866 red = green = blue = 0;
|
|
|
1867 }
|
|
|
1868 entry[afirst + (2 ^ bgr)] = (png_uint_16)blue;
|
|
|
1869 entry[afirst + 1] = (png_uint_16)green;
|
|
|
1870 entry[afirst + bgr] = (png_uint_16)red;
|
|
|
1871 break;
|
|
|
1872
|
|
|
1873 case 2:
|
|
|
1874 entry[1 ^ afirst] = (png_uint_16)alpha;
|
|
|
1875 /* FALL THROUGH */
|
|
|
1876
|
|
|
1877 case 1:
|
|
|
1878 if (alpha < 65535)
|
|
|
1879 {
|
|
|
1880 if (alpha > 0)
|
|
|
1881 green = (green * alpha + 32767U)/65535U;
|
|
|
1882
|
|
|
1883 else
|
|
|
1884 green = 0;
|
|
|
1885 }
|
|
|
1886 entry[afirst] = (png_uint_16)green;
|
|
|
1887 break;
|
|
|
1888
|
|
|
1889 default:
|
|
|
1890 break;
|
|
|
1891 }
|
|
|
1892 }
|
|
|
1893
|
|
|
1894 else /* output encoding is P_sRGB */
|
|
|
1895 {
|
|
|
1896 png_bytep entry = png_voidcast(png_bytep, display->colormap);
|
|
|
1897
|
|
|
1898 entry += ip * PNG_IMAGE_SAMPLE_CHANNELS(image->format);
|
|
|
1899
|
|
|
1900 switch (PNG_IMAGE_SAMPLE_CHANNELS(image->format))
|
|
|
1901 {
|
|
|
1902 case 4:
|
|
|
1903 entry[afirst ? 0 : 3] = (png_byte)alpha;
|
|
|
1904 case 3:
|
|
|
1905 entry[afirst + (2 ^ bgr)] = (png_byte)blue;
|
|
|
1906 entry[afirst + 1] = (png_byte)green;
|
|
|
1907 entry[afirst + bgr] = (png_byte)red;
|
|
|
1908 break;
|
|
|
1909
|
|
|
1910 case 2:
|
|
|
1911 entry[1 ^ afirst] = (png_byte)alpha;
|
|
|
1912 case 1:
|
|
|
1913 entry[afirst] = (png_byte)green;
|
|
|
1914 break;
|
|
|
1915
|
|
|
1916 default:
|
|
|
1917 break;
|
|
|
1918 }
|
|
|
1919 }
|
|
|
1920
|
|
|
1921 # ifdef afirst
|
|
|
1922 # undef afirst
|
|
|
1923 # endif
|
|
|
1924 # ifdef bgr
|
|
|
1925 # undef bgr
|
|
|
1926 # endif
|
|
|
1927 }
|
|
|
1928 }
|
|
|
1929
|
|
|
1930 static int
|
|
|
1931 make_gray_file_colormap(png_image_read_control *display)
|
|
|
1932 {
|
|
|
1933 unsigned int i;
|
|
|
1934
|
|
|
1935 for (i=0; i<256; ++i)
|
|
|
1936 png_create_colormap_entry(display, i, i, i, i, 255, P_FILE);
|
|
|
1937
|
|
|
1938 return i;
|
|
|
1939 }
|
|
|
1940
|
|
|
1941 static int
|
|
|
1942 make_gray_colormap(png_image_read_control *display)
|
|
|
1943 {
|
|
|
1944 unsigned int i;
|
|
|
1945
|
|
|
1946 for (i=0; i<256; ++i)
|
|
|
1947 png_create_colormap_entry(display, i, i, i, i, 255, P_sRGB);
|
|
|
1948
|
|
|
1949 return i;
|
|
|
1950 }
|
|
|
1951 #define PNG_GRAY_COLORMAP_ENTRIES 256
|
|
|
1952
|
|
|
1953 static int
|
|
|
1954 make_ga_colormap(png_image_read_control *display)
|
|
|
1955 {
|
|
|
1956 unsigned int i, a;
|
|
|
1957
|
|
|
1958 /* Alpha is retained, the output will be a color-map with entries
|
|
|
1959 * selected by six levels of alpha. One transparent entry, 6 gray
|
|
|
1960 * levels for all the intermediate alpha values, leaving 230 entries
|
|
|
1961 * for the opaque grays. The color-map entries are the six values
|
|
|
1962 * [0..5]*51, the GA processing uses PNG_DIV51(value) to find the
|
|
|
1963 * relevant entry.
|
|
|
1964 *
|
|
|
1965 * if (alpha > 229) // opaque
|
|
|
1966 * {
|
|
|
1967 * // The 231 entries are selected to make the math below work:
|
|
|
1968 * base = 0;
|
|
|
1969 * entry = (231 * gray + 128) >> 8;
|
|
|
1970 * }
|
|
|
1971 * else if (alpha < 26) // transparent
|
|
|
1972 * {
|
|
|
1973 * base = 231;
|
|
|
1974 * entry = 0;
|
|
|
1975 * }
|
|
|
1976 * else // partially opaque
|
|
|
1977 * {
|
|
|
1978 * base = 226 + 6 * PNG_DIV51(alpha);
|
|
|
1979 * entry = PNG_DIV51(gray);
|
|
|
1980 * }
|
|
|
1981 */
|
|
|
1982 i = 0;
|
|
|
1983 while (i < 231)
|
|
|
1984 {
|
|
|
1985 unsigned int gray = (i * 256 + 115) / 231;
|
|
|
1986 png_create_colormap_entry(display, i++, gray, gray, gray, 255, P_sRGB);
|
|
|
1987 }
|
|
|
1988
|
|
|
1989 /* 255 is used here for the component values for consistency with the code
|
|
|
1990 * that undoes premultiplication in pngwrite.c.
|
|
|
1991 */
|
|
|
1992 png_create_colormap_entry(display, i++, 255, 255, 255, 0, P_sRGB);
|
|
|
1993
|
|
|
1994 for (a=1; a<5; ++a)
|
|
|
1995 {
|
|
|
1996 unsigned int g;
|
|
|
1997
|
|
|
1998 for (g=0; g<6; ++g)
|
|
|
1999 png_create_colormap_entry(display, i++, g*51, g*51, g*51, a*51,
|
|
|
2000 P_sRGB);
|
|
|
2001 }
|
|
|
2002
|
|
|
2003 return i;
|
|
|
2004 }
|
|
|
2005
|
|
|
2006 #define PNG_GA_COLORMAP_ENTRIES 256
|
|
|
2007
|
|
|
2008 static int
|
|
|
2009 make_rgb_colormap(png_image_read_control *display)
|
|
|
2010 {
|
|
|
2011 unsigned int i, r;
|
|
|
2012
|
|
|
2013 /* Build a 6x6x6 opaque RGB cube */
|
|
|
2014 for (i=r=0; r<6; ++r)
|
|
|
2015 {
|
|
|
2016 unsigned int g;
|
|
|
2017
|
|
|
2018 for (g=0; g<6; ++g)
|
|
|
2019 {
|
|
|
2020 unsigned int b;
|
|
|
2021
|
|
|
2022 for (b=0; b<6; ++b)
|
|
|
2023 png_create_colormap_entry(display, i++, r*51, g*51, b*51, 255,
|
|
|
2024 P_sRGB);
|
|
|
2025 }
|
|
|
2026 }
|
|
|
2027
|
|
|
2028 return i;
|
|
|
2029 }
|
|
|
2030
|
|
|
2031 #define PNG_RGB_COLORMAP_ENTRIES 216
|
|
|
2032
|
|
|
2033 /* Return a palette index to the above palette given three 8-bit sRGB values. */
|
|
|
2034 #define PNG_RGB_INDEX(r,g,b) \
|
|
|
2035 ((png_byte)(6 * (6 * PNG_DIV51(r) + PNG_DIV51(g)) + PNG_DIV51(b)))
|
|
|
2036
|
|
|
2037 static int
|
|
|
2038 png_image_read_colormap(png_voidp argument)
|
|
|
2039 {
|
|
|
2040 png_image_read_control *display =
|
|
|
2041 png_voidcast(png_image_read_control*, argument);
|
|
|
2042 const png_imagep image = display->image;
|
|
|
2043
|
|
|
2044 const png_structrp png_ptr = image->opaque->png_ptr;
|
|
|
2045 const png_uint_32 output_format = image->format;
|
|
|
2046 const int output_encoding = (output_format & PNG_FORMAT_FLAG_LINEAR) ?
|
|
|
2047 P_LINEAR : P_sRGB;
|
|
|
2048
|
|
|
2049 unsigned int cmap_entries;
|
|
|
2050 unsigned int output_processing; /* Output processing option */
|
|
|
2051 unsigned int data_encoding = P_NOTSET; /* Encoding libpng must produce */
|
|
|
2052
|
|
|
2053 /* Background information; the background color and the index of this color
|
|
|
2054 * in the color-map if it exists (else 256).
|
|
|
2055 */
|
|
|
2056 unsigned int background_index = 256;
|
|
|
2057 png_uint_32 back_r, back_g, back_b;
|
|
|
2058
|
|
|
2059 /* Flags to accumulate things that need to be done to the input. */
|
|
|
2060 int expand_tRNS = 0;
|
|
|
2061
|
|
|
2062 /* Exclude the NYI feature of compositing onto a color-mapped buffer; it is
|
|
|
2063 * very difficult to do, the results look awful, and it is difficult to see
|
|
|
2064 * what possible use it is because the application can't control the
|
|
|
2065 * color-map.
|
|
|
2066 */
|
|
|
2067 if (((png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0 ||
|
|
|
2068 png_ptr->num_trans > 0) /* alpha in input */ &&
|
|
|
2069 ((output_format & PNG_FORMAT_FLAG_ALPHA) == 0) /* no alpha in output */)
|
|
|
2070 {
|
|
|
2071 if (output_encoding == P_LINEAR) /* compose on black */
|
|
|
2072 back_b = back_g = back_r = 0;
|
|
|
2073
|
|
|
2074 else if (display->background == NULL /* no way to remove it */)
|
|
|
2075 png_error(png_ptr,
|
|
|
2076 "a background color must be supplied to remove alpha/transparency");
|
|
|
2077
|
|
|
2078 /* Get a copy of the background color (this avoids repeating the checks
|
|
|
2079 * below.) The encoding is 8-bit sRGB or 16-bit linear, depending on the
|
|
|
2080 * output format.
|
|
|
2081 */
|
|
|
2082 else
|
|
|
2083 {
|
|
|
2084 back_g = display->background->green;
|
|
|
2085 if (output_format & PNG_FORMAT_FLAG_COLOR)
|
|
|
2086 {
|
|
|
2087 back_r = display->background->red;
|
|
|
2088 back_b = display->background->blue;
|
|
|
2089 }
|
|
|
2090 else
|
|
|
2091 back_b = back_r = back_g;
|
|
|
2092 }
|
|
|
2093 }
|
|
|
2094
|
|
|
2095 else if (output_encoding == P_LINEAR)
|
|
|
2096 back_b = back_r = back_g = 65535;
|
|
|
2097
|
|
|
2098 else
|
|
|
2099 back_b = back_r = back_g = 255;
|
|
|
2100
|
|
|
2101 /* Default the input file gamma if required - this is necessary because
|
|
|
2102 * libpng assumes that if no gamma information is present the data is in the
|
|
|
2103 * output format, but the simplified API deduces the gamma from the input
|
|
|
2104 * format.
|
|
|
2105 */
|
|
|
2106 if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) == 0)
|
|
|
2107 {
|
|
|
2108 /* Do this directly, not using the png_colorspace functions, to ensure
|
|
|
2109 * that it happens even if the colorspace is invalid (though probably if
|
|
|
2110 * it is the setting will be ignored) Note that the same thing can be
|
|
|
2111 * achieved at the application interface with png_set_gAMA.
|
|
|
2112 */
|
|
|
2113 if (png_ptr->bit_depth == 16 &&
|
|
|
2114 (image->flags & PNG_IMAGE_FLAG_16BIT_sRGB) == 0)
|
|
|
2115 png_ptr->colorspace.gamma = PNG_GAMMA_LINEAR;
|
|
|
2116
|
|
|
2117 else
|
|
|
2118 png_ptr->colorspace.gamma = PNG_GAMMA_sRGB_INVERSE;
|
|
|
2119
|
|
|
2120 png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
|
|
|
2121 }
|
|
|
2122
|
|
|
2123 /* Decide what to do based on the PNG color type of the input data. The
|
|
|
2124 * utility function png_create_colormap_entry deals with most aspects of the
|
|
|
2125 * output transformations; this code works out how to produce bytes of
|
|
|
2126 * color-map entries from the original format.
|
|
|
2127 */
|
|
|
2128 switch (png_ptr->color_type)
|
|
|
2129 {
|
|
|
2130 case PNG_COLOR_TYPE_GRAY:
|
|
|
2131 if (png_ptr->bit_depth <= 8)
|
|
|
2132 {
|
|
|
2133 /* There at most 256 colors in the output, regardless of
|
|
|
2134 * transparency.
|
|
|
2135 */
|
|
|
2136 unsigned int step, i, val, trans = 256/*ignore*/, back_alpha = 0;
|
|
|
2137
|
|
|
2138 cmap_entries = 1U << png_ptr->bit_depth;
|
|
|
2139 if (cmap_entries > image->colormap_entries)
|
|
|
2140 png_error(png_ptr, "gray[8] color-map: too few entries");
|
|
|
2141
|
|
|
2142 step = 255 / (cmap_entries - 1);
|
|
|
2143 output_processing = PNG_CMAP_NONE;
|
|
|
2144
|
|
|
2145 /* If there is a tRNS chunk then this either selects a transparent
|
|
|
2146 * value or, if the output has no alpha, the background color.
|
|
|
2147 */
|
|
|
2148 if (png_ptr->num_trans > 0)
|
|
|
2149 {
|
|
|
2150 trans = png_ptr->trans_color.gray;
|
|
|
2151
|
|
|
2152 if ((output_format & PNG_FORMAT_FLAG_ALPHA) == 0)
|
|
|
2153 back_alpha = output_encoding == P_LINEAR ? 65535 : 255;
|
|
|
2154 }
|
|
|
2155
|
|
|
2156 /* png_create_colormap_entry just takes an RGBA and writes the
|
|
|
2157 * corresponding color-map entry using the format from 'image',
|
|
|
2158 * including the required conversion to sRGB or linear as
|
|
|
2159 * appropriate. The input values are always either sRGB (if the
|
|
|
2160 * gamma correction flag is 0) or 0..255 scaled file encoded values
|
|
|
2161 * (if the function must gamma correct them).
|
|
|
2162 */
|
|
|
2163 for (i=val=0; i<cmap_entries; ++i, val += step)
|
|
|
2164 {
|
|
|
2165 /* 'i' is a file value. While this will result in duplicated
|
|
|
2166 * entries for 8-bit non-sRGB encoded files it is necessary to
|
|
|
2167 * have non-gamma corrected values to do tRNS handling.
|
|
|
2168 */
|
|
|
2169 if (i != trans)
|
|
|
2170 png_create_colormap_entry(display, i, val, val, val, 255,
|
|
|
2171 P_FILE/*8-bit with file gamma*/);
|
|
|
2172
|
|
|
2173 /* Else this entry is transparent. The colors don't matter if
|
|
|
2174 * there is an alpha channel (back_alpha == 0), but it does no
|
|
|
2175 * harm to pass them in; the values are not set above so this
|
|
|
2176 * passes in white.
|
|
|
2177 *
|
|
|
2178 * NOTE: this preserves the full precision of the application
|
|
|
2179 * supplied background color when it is used.
|
|
|
2180 */
|
|
|
2181 else
|
|
|
2182 png_create_colormap_entry(display, i, back_r, back_g, back_b,
|
|
|
2183 back_alpha, output_encoding);
|
|
|
2184 }
|
|
|
2185
|
|
|
2186 /* We need libpng to preserve the original encoding. */
|
|
|
2187 data_encoding = P_FILE;
|
|
|
2188
|
|
|
2189 /* The rows from libpng, while technically gray values, are now also
|
|
|
2190 * color-map indicies; however, they may need to be expanded to 1
|
|
|
2191 * byte per pixel. This is what png_set_packing does (i.e., it
|
|
|
2192 * unpacks the bit values into bytes.)
|
|
|
2193 */
|
|
|
2194 if (png_ptr->bit_depth < 8)
|
|
|
2195 png_set_packing(png_ptr);
|
|
|
2196 }
|
|
|
2197
|
|
|
2198 else /* bit depth is 16 */
|
|
|
2199 {
|
|
|
2200 /* The 16-bit input values can be converted directly to 8-bit gamma
|
|
|
2201 * encoded values; however, if a tRNS chunk is present 257 color-map
|
|
|
2202 * entries are required. This means that the extra entry requires
|
|
|
2203 * special processing; add an alpha channel, sacrifice gray level
|
|
|
2204 * 254 and convert transparent (alpha==0) entries to that.
|
|
|
2205 *
|
|
|
2206 * Use libpng to chop the data to 8 bits. Convert it to sRGB at the
|
|
|
2207 * same time to minimize quality loss. If a tRNS chunk is present
|
|
|
2208 * this means libpng must handle it too; otherwise it is impossible
|
|
|
2209 * to do the exact match on the 16-bit value.
|
|
|
2210 *
|
|
|
2211 * If the output has no alpha channel *and* the background color is
|
|
|
2212 * gray then it is possible to let libpng handle the substitution by
|
|
|
2213 * ensuring that the corresponding gray level matches the background
|
|
|
2214 * color exactly.
|
|
|
2215 */
|
|
|
2216 data_encoding = P_sRGB;
|
|
|
2217
|
|
|
2218 if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries)
|
|
|
2219 png_error(png_ptr, "gray[16] color-map: too few entries");
|
|
|
2220
|
|
|
2221 cmap_entries = make_gray_colormap(display);
|
|
|
2222
|
|
|
2223 if (png_ptr->num_trans > 0)
|
|
|
2224 {
|
|
|
2225 unsigned int back_alpha;
|
|
|
2226
|
|
|
2227 if (output_format & PNG_FORMAT_FLAG_ALPHA)
|
|
|
2228 back_alpha = 0;
|
|
|
2229
|
|
|
2230 else
|
|
|
2231 {
|
|
|
2232 if (back_r == back_g && back_g == back_b)
|
|
|
2233 {
|
|
|
2234 /* Background is gray; no special processing will be
|
|
|
2235 * required.
|
|
|
2236 */
|
|
|
2237 png_color_16 c;
|
|
|
2238 png_uint_32 gray = back_g;
|
|
|
2239
|
|
|
2240 if (output_encoding == P_LINEAR)
|
|
|
2241 {
|
|
|
2242 gray = PNG_sRGB_FROM_LINEAR(gray * 255);
|
|
|
2243
|
|
|
2244 /* And make sure the corresponding palette entry
|
|
|
2245 * matches.
|
|
|
2246 */
|
|
|
2247 png_create_colormap_entry(display, gray, back_g, back_g,
|
|
|
2248 back_g, 65535, P_LINEAR);
|
|
|
2249 }
|
|
|
2250
|
|
|
2251 /* The background passed to libpng, however, must be the
|
|
|
2252 * sRGB value.
|
|
|
2253 */
|
|
|
2254 c.index = 0; /*unused*/
|
|
|
2255 c.gray = c.red = c.green = c.blue = (png_uint_16)gray;
|
|
|
2256
|
|
|
2257 /* NOTE: does this work without expanding tRNS to alpha?
|
|
|
2258 * It should be the color->gray case below apparently
|
|
|
2259 * doesn't.
|
|
|
2260 */
|
|
|
2261 png_set_background_fixed(png_ptr, &c,
|
|
|
2262 PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
|
|
|
2263 0/*gamma: not used*/);
|
|
|
2264
|
|
|
2265 output_processing = PNG_CMAP_NONE;
|
|
|
2266 break;
|
|
|
2267 }
|
|
|
2268
|
|
|
2269 back_alpha = output_encoding == P_LINEAR ? 65535 : 255;
|
|
|
2270 }
|
|
|
2271
|
|
|
2272 /* output_processing means that the libpng-processed row will be
|
|
|
2273 * 8-bit GA and it has to be processing to single byte color-map
|
|
|
2274 * values. Entry 254 is replaced by either a completely
|
|
|
2275 * transparent entry or by the background color at full
|
|
|
2276 * precision (and the background color is not a simple gray leve
|
|
|
2277 * in this case.)
|
|
|
2278 */
|
|
|
2279 expand_tRNS = 1;
|
|
|
2280 output_processing = PNG_CMAP_TRANS;
|
|
|
2281 background_index = 254;
|
|
|
2282
|
|
|
2283 /* And set (overwrite) color-map entry 254 to the actual
|
|
|
2284 * background color at full precision.
|
|
|
2285 */
|
|
|
2286 png_create_colormap_entry(display, 254, back_r, back_g, back_b,
|
|
|
2287 back_alpha, output_encoding);
|
|
|
2288 }
|
|
|
2289
|
|
|
2290 else
|
|
|
2291 output_processing = PNG_CMAP_NONE;
|
|
|
2292 }
|
|
|
2293 break;
|
|
|
2294
|
|
|
2295 case PNG_COLOR_TYPE_GRAY_ALPHA:
|
|
|
2296 /* 8-bit or 16-bit PNG with two channels - gray and alpha. A minimum
|
|
|
2297 * of 65536 combinations. If, however, the alpha channel is to be
|
|
|
2298 * removed there are only 256 possibilities if the background is gray.
|
|
|
2299 * (Otherwise there is a subset of the 65536 possibilities defined by
|
|
|
2300 * the triangle between black, white and the background color.)
|
|
|
2301 *
|
|
|
2302 * Reduce 16-bit files to 8-bit and sRGB encode the result. No need to
|
|
|
2303 * worry about tRNS matching - tRNS is ignored if there is an alpha
|
|
|
2304 * channel.
|
|
|
2305 */
|
|
|
2306 data_encoding = P_sRGB;
|
|
|
2307
|
|
|
2308 if (output_format & PNG_FORMAT_FLAG_ALPHA)
|
|
|
2309 {
|
|
|
2310 if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries)
|
|
|
2311 png_error(png_ptr, "gray+alpha color-map: too few entries");
|
|
|
2312
|
|
|
2313 cmap_entries = make_ga_colormap(display);
|
|
|
2314
|
|
|
2315 background_index = PNG_CMAP_GA_BACKGROUND;
|
|
|
2316 output_processing = PNG_CMAP_GA;
|
|
|
2317 }
|
|
|
2318
|
|
|
2319 else /* alpha is removed */
|
|
|
2320 {
|
|
|
2321 /* Alpha must be removed as the PNG data is processed when the
|
|
|
2322 * background is a color because the G and A channels are
|
|
|
2323 * independent and the vector addition (non-parallel vectors) is a
|
|
|
2324 * 2-D problem.
|
|
|
2325 *
|
|
|
2326 * This can be reduced to the same algorithm as above by making a
|
|
|
2327 * colormap containing gray levels (for the opaque grays), a
|
|
|
2328 * background entry (for a transparent pixel) and a set of four six
|
|
|
2329 * level color values, one set for each intermediate alpha value.
|
|
|
2330 * See the comments in make_ga_colormap for how this works in the
|
|
|
2331 * per-pixel processing.
|
|
|
2332 *
|
|
|
2333 * If the background is gray, however, we only need a 256 entry gray
|
|
|
2334 * level color map. It is sufficient to make the entry generated
|
|
|
2335 * for the background color be exactly the color specified.
|
|
|
2336 */
|
|
|
2337 if ((output_format & PNG_FORMAT_FLAG_COLOR) == 0 ||
|
|
|
2338 (back_r == back_g && back_g == back_b))
|
|
|
2339 {
|
|
|
2340 /* Background is gray; no special processing will be required. */
|
|
|
2341 png_color_16 c;
|
|
|
2342 png_uint_32 gray = back_g;
|
|
|
2343
|
|
|
2344 if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries)
|
|
|
2345 png_error(png_ptr, "gray-alpha color-map: too few entries");
|
|
|
2346
|
|
|
2347 cmap_entries = make_gray_colormap(display);
|
|
|
2348
|
|
|
2349 if (output_encoding == P_LINEAR)
|
|
|
2350 {
|
|
|
2351 gray = PNG_sRGB_FROM_LINEAR(gray * 255);
|
|
|
2352
|
|
|
2353 /* And make sure the corresponding palette entry matches. */
|
|
|
2354 png_create_colormap_entry(display, gray, back_g, back_g,
|
|
|
2355 back_g, 65535, P_LINEAR);
|
|
|
2356 }
|
|
|
2357
|
|
|
2358 /* The background passed to libpng, however, must be the sRGB
|
|
|
2359 * value.
|
|
|
2360 */
|
|
|
2361 c.index = 0; /*unused*/
|
|
|
2362 c.gray = c.red = c.green = c.blue = (png_uint_16)gray;
|
|
|
2363
|
|
|
2364 png_set_background_fixed(png_ptr, &c,
|
|
|
2365 PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
|
|
|
2366 0/*gamma: not used*/);
|
|
|
2367
|
|
|
2368 output_processing = PNG_CMAP_NONE;
|
|
|
2369 }
|
|
|
2370
|
|
|
2371 else
|
|
|
2372 {
|
|
|
2373 png_uint_32 i, a;
|
|
|
2374
|
|
|
2375 /* This is the same as png_make_ga_colormap, above, except that
|
|
|
2376 * the entries are all opaque.
|
|
|
2377 */
|
|
|
2378 if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries)
|
|
|
2379 png_error(png_ptr, "ga-alpha color-map: too few entries");
|
|
|
2380
|
|
|
2381 i = 0;
|
|
|
2382 while (i < 231)
|
|
|
2383 {
|
|
|
2384 png_uint_32 gray = (i * 256 + 115) / 231;
|
|
|
2385 png_create_colormap_entry(display, i++, gray, gray, gray,
|
|
|
2386 255, P_sRGB);
|
|
|
2387 }
|
|
|
2388
|
|
|
2389 /* NOTE: this preserves the full precision of the application
|
|
|
2390 * background color.
|
|
|
2391 */
|
|
|
2392 background_index = i;
|
|
|
2393 png_create_colormap_entry(display, i++, back_r, back_g, back_b,
|
|
|
2394 output_encoding == P_LINEAR ? 65535U : 255U, output_encoding);
|
|
|
2395
|
|
|
2396 /* For non-opaque input composite on the sRGB background - this
|
|
|
2397 * requires inverting the encoding for each component. The input
|
|
|
2398 * is still converted to the sRGB encoding because this is a
|
|
|
2399 * reasonable approximate to the logarithmic curve of human
|
|
|
2400 * visual sensitivity, at least over the narrow range which PNG
|
|
|
2401 * represents. Consequently 'G' is always sRGB encoded, while
|
|
|
2402 * 'A' is linear. We need the linear background colors.
|
|
|
2403 */
|
|
|
2404 if (output_encoding == P_sRGB) /* else already linear */
|
|
|
2405 {
|
|
|
2406 /* This may produce a value not exactly matching the
|
|
|
2407 * background, but that's ok because these numbers are only
|
|
|
2408 * used when alpha != 0
|
|
|
2409 */
|
|
|
2410 back_r = png_sRGB_table[back_r];
|
|
|
2411 back_g = png_sRGB_table[back_g];
|
|
|
2412 back_b = png_sRGB_table[back_b];
|
|
|
2413 }
|
|
|
2414
|
|
|
2415 for (a=1; a<5; ++a)
|
|
|
2416 {
|
|
|
2417 unsigned int g;
|
|
|
2418
|
|
|
2419 /* PNG_sRGB_FROM_LINEAR expects a 16-bit linear value scaled
|
|
|
2420 * by an 8-bit alpha value (0..255).
|
|
|
2421 */
|
|
|
2422 png_uint_32 alpha = 51 * a;
|
|
|
2423 png_uint_32 back_rx = (255-alpha) * back_r;
|
|
|
2424 png_uint_32 back_gx = (255-alpha) * back_g;
|
|
|
2425 png_uint_32 back_bx = (255-alpha) * back_b;
|
|
|
2426
|
|
|
2427 for (g=0; g<6; ++g)
|
|
|
2428 {
|
|
|
2429 png_uint_32 gray = png_sRGB_table[g*51] * alpha;
|
|
|
2430
|
|
|
2431 png_create_colormap_entry(display, i++,
|
|
|
2432 PNG_sRGB_FROM_LINEAR(gray + back_rx),
|
|
|
2433 PNG_sRGB_FROM_LINEAR(gray + back_gx),
|
|
|
2434 PNG_sRGB_FROM_LINEAR(gray + back_bx), 255, P_sRGB);
|
|
|
2435 }
|
|
|
2436 }
|
|
|
2437
|
|
|
2438 cmap_entries = i;
|
|
|
2439 output_processing = PNG_CMAP_GA;
|
|
|
2440 }
|
|
|
2441 }
|
|
|
2442 break;
|
|
|
2443
|
|
|
2444 case PNG_COLOR_TYPE_RGB:
|
|
|
2445 case PNG_COLOR_TYPE_RGB_ALPHA:
|
|
|
2446 /* Exclude the case where the output is gray; we can always handle this
|
|
|
2447 * with the cases above.
|
|
|
2448 */
|
|
|
2449 if ((output_format & PNG_FORMAT_FLAG_COLOR) == 0)
|
|
|
2450 {
|
|
|
2451 /* The color-map will be grayscale, so we may as well convert the
|
|
|
2452 * input RGB values to a simple grayscale and use the grayscale
|
|
|
2453 * code above.
|
|
|
2454 *
|
|
|
2455 * NOTE: calling this apparently damages the recognition of the
|
|
|
2456 * transparent color in background color handling; call
|
|
|
2457 * png_set_tRNS_to_alpha before png_set_background_fixed.
|
|
|
2458 */
|
|
|
2459 png_set_rgb_to_gray_fixed(png_ptr, PNG_ERROR_ACTION_NONE, -1,
|
|
|
2460 -1);
|
|
|
2461 data_encoding = P_sRGB;
|
|
|
2462
|
|
|
2463 /* The output will now be one or two 8-bit gray or gray+alpha
|
|
|
2464 * channels. The more complex case arises when the input has alpha.
|
|
|
2465 */
|
|
|
2466 if ((png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
|
|
|
2467 png_ptr->num_trans > 0) &&
|
|
|
2468 (output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
|
|
|
2469 {
|
|
|
2470 /* Both input and output have an alpha channel, so no background
|
|
|
2471 * processing is required; just map the GA bytes to the right
|
|
|
2472 * color-map entry.
|
|
|
2473 */
|
|
|
2474 expand_tRNS = 1;
|
|
|
2475
|
|
|
2476 if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries)
|
|
|
2477 png_error(png_ptr, "rgb[ga] color-map: too few entries");
|
|
|
2478
|
|
|
2479 cmap_entries = make_ga_colormap(display);
|
|
|
2480 background_index = PNG_CMAP_GA_BACKGROUND;
|
|
|
2481 output_processing = PNG_CMAP_GA;
|
|
|
2482 }
|
|
|
2483
|
|
|
2484 else
|
|
|
2485 {
|
|
|
2486 /* Either the input or the output has no alpha channel, so there
|
|
|
2487 * will be no non-opaque pixels in the color-map; it will just be
|
|
|
2488 * grayscale.
|
|
|
2489 */
|
|
|
2490 if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries)
|
|
|
2491 png_error(png_ptr, "rgb[gray] color-map: too few entries");
|
|
|
2492
|
|
|
2493 /* Ideally this code would use libpng to do the gamma correction,
|
|
|
2494 * but if an input alpha channel is to be removed we will hit the
|
|
|
2495 * libpng bug in gamma+compose+rgb-to-gray (the double gamma
|
|
|
2496 * correction bug). Fix this by dropping the gamma correction in
|
|
|
2497 * this case and doing it in the palette; this will result in
|
|
|
2498 * duplicate palette entries, but that's better than the
|
|
|
2499 * alternative of double gamma correction.
|
|
|
2500 */
|
|
|
2501 if ((png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
|
|
|
2502 png_ptr->num_trans > 0) &&
|
|
|
2503 png_gamma_not_sRGB(png_ptr->colorspace.gamma))
|
|
|
2504 {
|
|
|
2505 cmap_entries = make_gray_file_colormap(display);
|
|
|
2506 data_encoding = P_FILE;
|
|
|
2507 }
|
|
|
2508
|
|
|
2509 else
|
|
|
2510 cmap_entries = make_gray_colormap(display);
|
|
|
2511
|
|
|
2512 /* But if the input has alpha or transparency it must be removed
|
|
|
2513 */
|
|
|
2514 if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
|
|
|
2515 png_ptr->num_trans > 0)
|
|
|
2516 {
|
|
|
2517 png_color_16 c;
|
|
|
2518 png_uint_32 gray = back_g;
|
|
|
2519
|
|
|
2520 /* We need to ensure that the application background exists in
|
|
|
2521 * the colormap and that completely transparent pixels map to
|
|
|
2522 * it. Achieve this simply by ensuring that the entry
|
|
|
2523 * selected for the background really is the background color.
|
|
|
2524 */
|
|
|
2525 if (data_encoding == P_FILE) /* from the fixup above */
|
|
|
2526 {
|
|
|
2527 /* The app supplied a gray which is in output_encoding, we
|
|
|
2528 * need to convert it to a value of the input (P_FILE)
|
|
|
2529 * encoding then set this palette entry to the required
|
|
|
2530 * output encoding.
|
|
|
2531 */
|
|
|
2532 if (output_encoding == P_sRGB)
|
|
|
2533 gray = png_sRGB_table[gray]; /* now P_LINEAR */
|
|
|
2534
|
|
|
2535 gray = PNG_DIV257(png_gamma_16bit_correct(gray,
|
|
|
2536 png_ptr->colorspace.gamma)); /* now P_FILE */
|
|
|
2537
|
|
|
2538 /* And make sure the corresponding palette entry contains
|
|
|
2539 * exactly the required sRGB value.
|
|
|
2540 */
|
|
|
2541 png_create_colormap_entry(display, gray, back_g, back_g,
|
|
|
2542 back_g, 0/*unused*/, output_encoding);
|
|
|
2543 }
|
|
|
2544
|
|
|
2545 else if (output_encoding == P_LINEAR)
|
|
|
2546 {
|
|
|
2547 gray = PNG_sRGB_FROM_LINEAR(gray * 255);
|
|
|
2548
|
|
|
2549 /* And make sure the corresponding palette entry matches.
|
|
|
2550 */
|
|
|
2551 png_create_colormap_entry(display, gray, back_g, back_g,
|
|
|
2552 back_g, 0/*unused*/, P_LINEAR);
|
|
|
2553 }
|
|
|
2554
|
|
|
2555 /* The background passed to libpng, however, must be the
|
|
|
2556 * output (normally sRGB) value.
|
|
|
2557 */
|
|
|
2558 c.index = 0; /*unused*/
|
|
|
2559 c.gray = c.red = c.green = c.blue = (png_uint_16)gray;
|
|
|
2560
|
|
|
2561 /* NOTE: the following is apparently a bug in libpng. Without
|
|
|
2562 * it the transparent color recognition in
|
|
|
2563 * png_set_background_fixed seems to go wrong.
|
|
|
2564 */
|
|
|
2565 expand_tRNS = 1;
|
|
|
2566 png_set_background_fixed(png_ptr, &c,
|
|
|
2567 PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
|
|
|
2568 0/*gamma: not used*/);
|
|
|
2569 }
|
|
|
2570
|
|
|
2571 output_processing = PNG_CMAP_NONE;
|
|
|
2572 }
|
|
|
2573 }
|
|
|
2574
|
|
|
2575 else /* output is color */
|
|
|
2576 {
|
|
|
2577 /* We could use png_quantize here so long as there is no transparent
|
|
|
2578 * color or alpha; png_quantize ignores alpha. Easier overall just
|
|
|
2579 * to do it once and using PNG_DIV51 on the 6x6x6 reduced RGB cube.
|
|
|
2580 * Consequently we always want libpng to produce sRGB data.
|
|
|
2581 */
|
|
|
2582 data_encoding = P_sRGB;
|
|
|
2583
|
|
|
2584 /* Is there any transparency or alpha? */
|
|
|
2585 if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
|
|
|
2586 png_ptr->num_trans > 0)
|
|
|
2587 {
|
|
|
2588 /* Is there alpha in the output too? If so all four channels are
|
|
|
2589 * processed into a special RGB cube with alpha support.
|
|
|
2590 */
|
|
|
2591 if (output_format & PNG_FORMAT_FLAG_ALPHA)
|
|
|
2592 {
|
|
|
2593 png_uint_32 r;
|
|
|
2594
|
|
|
2595 if (PNG_RGB_COLORMAP_ENTRIES+1+27 > image->colormap_entries)
|
|
|
2596 png_error(png_ptr, "rgb+alpha color-map: too few entries");
|
|
|
2597
|
|
|
2598 cmap_entries = make_rgb_colormap(display);
|
|
|
2599
|
|
|
2600 /* Add a transparent entry. */
|
|
|
2601 png_create_colormap_entry(display, cmap_entries, 255, 255,
|
|
|
2602 255, 0, P_sRGB);
|
|
|
2603
|
|
|
2604 /* This is stored as the background index for the processing
|
|
|
2605 * algorithm.
|
|
|
2606 */
|
|
|
2607 background_index = cmap_entries++;
|
|
|
2608
|
|
|
2609 /* Add 27 r,g,b entries each with alpha 0.5. */
|
|
|
2610 for (r=0; r<256; r = (r << 1) | 0x7f)
|
|
|
2611 {
|
|
|
2612 png_uint_32 g;
|
|
|
2613
|
|
|
2614 for (g=0; g<256; g = (g << 1) | 0x7f)
|
|
|
2615 {
|
|
|
2616 png_uint_32 b;
|
|
|
2617
|
|
|
2618 /* This generates components with the values 0, 127 and
|
|
|
2619 * 255
|
|
|
2620 */
|
|
|
2621 for (b=0; b<256; b = (b << 1) | 0x7f)
|
|
|
2622 png_create_colormap_entry(display, cmap_entries++,
|
|
|
2623 r, g, b, 128, P_sRGB);
|
|
|
2624 }
|
|
|
2625 }
|
|
|
2626
|
|
|
2627 expand_tRNS = 1;
|
|
|
2628 output_processing = PNG_CMAP_RGB_ALPHA;
|
|
|
2629 }
|
|
|
2630
|
|
|
2631 else
|
|
|
2632 {
|
|
|
2633 /* Alpha/transparency must be removed. The background must
|
|
|
2634 * exist in the color map (achieved by setting adding it after
|
|
|
2635 * the 666 color-map). If the standard processing code will
|
|
|
2636 * pick up this entry automatically that's all that is
|
|
|
2637 * required; libpng can be called to do the background
|
|
|
2638 * processing.
|
|
|
2639 */
|
|
|
2640 unsigned int sample_size =
|
|
|
2641 PNG_IMAGE_SAMPLE_SIZE(output_format);
|
|
|
2642 png_uint_32 r, g, b; /* sRGB background */
|
|
|
2643
|
|
|
2644 if (PNG_RGB_COLORMAP_ENTRIES+1+27 > image->colormap_entries)
|
|
|
2645 png_error(png_ptr, "rgb-alpha color-map: too few entries");
|
|
|
2646
|
|
|
2647 cmap_entries = make_rgb_colormap(display);
|
|
|
2648
|
|
|
2649 png_create_colormap_entry(display, cmap_entries, back_r,
|
|
|
2650 back_g, back_b, 0/*unused*/, output_encoding);
|
|
|
2651
|
|
|
2652 if (output_encoding == P_LINEAR)
|
|
|
2653 {
|
|
|
2654 r = PNG_sRGB_FROM_LINEAR(back_r * 255);
|
|
|
2655 g = PNG_sRGB_FROM_LINEAR(back_g * 255);
|
|
|
2656 b = PNG_sRGB_FROM_LINEAR(back_b * 255);
|
|
|
2657 }
|
|
|
2658
|
|
|
2659 else
|
|
|
2660 {
|
|
|
2661 r = back_r;
|
|
|
2662 g = back_g;
|
|
|
2663 b = back_g;
|
|
|
2664 }
|
|
|
2665
|
|
|
2666 /* Compare the newly-created color-map entry with the one the
|
|
|
2667 * PNG_CMAP_RGB algorithm will use. If the two entries don't
|
|
|
2668 * match, add the new one and set this as the background
|
|
|
2669 * index.
|
|
|
2670 */
|
|
|
2671 if (memcmp((png_const_bytep)display->colormap +
|
|
|
2672 sample_size * cmap_entries,
|
|
|
2673 (png_const_bytep)display->colormap +
|
|
|
2674 sample_size * PNG_RGB_INDEX(r,g,b),
|
|
|
2675 sample_size) != 0)
|
|
|
2676 {
|
|
|
2677 /* The background color must be added. */
|
|
|
2678 background_index = cmap_entries++;
|
|
|
2679
|
|
|
2680 /* Add 27 r,g,b entries each with created by composing with
|
|
|
2681 * the background at alpha 0.5.
|
|
|
2682 */
|
|
|
2683 for (r=0; r<256; r = (r << 1) | 0x7f)
|
|
|
2684 {
|
|
|
2685 for (g=0; g<256; g = (g << 1) | 0x7f)
|
|
|
2686 {
|
|
|
2687 /* This generates components with the values 0, 127
|
|
|
2688 * and 255
|
|
|
2689 */
|
|
|
2690 for (b=0; b<256; b = (b << 1) | 0x7f)
|
|
|
2691 png_create_colormap_entry(display, cmap_entries++,
|
|
|
2692 png_colormap_compose(display, r, P_sRGB, 128,
|
|
|
2693 back_r, output_encoding),
|
|
|
2694 png_colormap_compose(display, g, P_sRGB, 128,
|
|
|
2695 back_g, output_encoding),
|
|
|
2696 png_colormap_compose(display, b, P_sRGB, 128,
|
|
|
2697 back_b, output_encoding),
|
|
|
2698 0/*unused*/, output_encoding);
|
|
|
2699 }
|
|
|
2700 }
|
|
|
2701
|
|
|
2702 expand_tRNS = 1;
|
|
|
2703 output_processing = PNG_CMAP_RGB_ALPHA;
|
|
|
2704 }
|
|
|
2705
|
|
|
2706 else /* background color is in the standard color-map */
|
|
|
2707 {
|
|
|
2708 png_color_16 c;
|
|
|
2709
|
|
|
2710 c.index = 0; /*unused*/
|
|
|
2711 c.red = (png_uint_16)back_r;
|
|
|
2712 c.gray = c.green = (png_uint_16)back_g;
|
|
|
2713 c.blue = (png_uint_16)back_b;
|
|
|
2714
|
|
|
2715 png_set_background_fixed(png_ptr, &c,
|
|
|
2716 PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
|
|
|
2717 0/*gamma: not used*/);
|
|
|
2718
|
|
|
2719 output_processing = PNG_CMAP_RGB;
|
|
|
2720 }
|
|
|
2721 }
|
|
|
2722 }
|
|
|
2723
|
|
|
2724 else /* no alpha or transparency in the input */
|
|
|
2725 {
|
|
|
2726 /* Alpha in the output is irrelevant, simply map the opaque input
|
|
|
2727 * pixels to the 6x6x6 color-map.
|
|
|
2728 */
|
|
|
2729 if (PNG_RGB_COLORMAP_ENTRIES > image->colormap_entries)
|
|
|
2730 png_error(png_ptr, "rgb color-map: too few entries");
|
|
|
2731
|
|
|
2732 cmap_entries = make_rgb_colormap(display);
|
|
|
2733 output_processing = PNG_CMAP_RGB;
|
|
|
2734 }
|
|
|
2735 }
|
|
|
2736 break;
|
|
|
2737
|
|
|
2738 case PNG_COLOR_TYPE_PALETTE:
|
|
|
2739 /* It's already got a color-map. It may be necessary to eliminate the
|
|
|
2740 * tRNS entries though.
|
|
|
2741 */
|
|
|
2742 {
|
|
|
2743 unsigned int num_trans = png_ptr->num_trans;
|
|
|
2744 png_const_bytep trans = num_trans > 0 ? png_ptr->trans_alpha : NULL;
|
|
|
2745 png_const_colorp colormap = png_ptr->palette;
|
|
|
2746 const int do_background = trans != NULL &&
|
|
|
2747 (output_format & PNG_FORMAT_FLAG_ALPHA) == 0;
|
|
|
2748 unsigned int i;
|
|
|
2749
|
|
|
2750 /* Just in case: */
|
|
|
2751 if (trans == NULL)
|
|
|
2752 num_trans = 0;
|
|
|
2753
|
|
|
2754 output_processing = PNG_CMAP_NONE;
|
|
|
2755 data_encoding = P_FILE; /* Don't change from color-map indicies */
|
|
|
2756 cmap_entries = png_ptr->num_palette;
|
|
|
2757 if (cmap_entries > 256)
|
|
|
2758 cmap_entries = 256;
|
|
|
2759
|
|
|
2760 if (cmap_entries > image->colormap_entries)
|
|
|
2761 png_error(png_ptr, "palette color-map: too few entries");
|
|
|
2762
|
|
|
2763 for (i=0; i < cmap_entries; ++i)
|
|
|
2764 {
|
|
|
2765 if (do_background && i < num_trans && trans[i] < 255)
|
|
|
2766 {
|
|
|
2767 if (trans[i] == 0)
|
|
|
2768 png_create_colormap_entry(display, i, back_r, back_g,
|
|
|
2769 back_b, 0, output_encoding);
|
|
|
2770
|
|
|
2771 else
|
|
|
2772 {
|
|
|
2773 /* Must compose the PNG file color in the color-map entry
|
|
|
2774 * on the sRGB color in 'back'.
|
|
|
2775 */
|
|
|
2776 png_create_colormap_entry(display, i,
|
|
|
2777 png_colormap_compose(display, colormap[i].red, P_FILE,
|
|
|
2778 trans[i], back_r, output_encoding),
|
|
|
2779 png_colormap_compose(display, colormap[i].green, P_FILE,
|
|
|
2780 trans[i], back_g, output_encoding),
|
|
|
2781 png_colormap_compose(display, colormap[i].blue, P_FILE,
|
|
|
2782 trans[i], back_b, output_encoding),
|
|
|
2783 output_encoding == P_LINEAR ? trans[i] * 257U :
|
|
|
2784 trans[i],
|
|
|
2785 output_encoding);
|
|
|
2786 }
|
|
|
2787 }
|
|
|
2788
|
|
|
2789 else
|
|
|
2790 png_create_colormap_entry(display, i, colormap[i].red,
|
|
|
2791 colormap[i].green, colormap[i].blue,
|
|
|
2792 i < num_trans ? trans[i] : 255U, P_FILE/*8-bit*/);
|
|
|
2793 }
|
|
|
2794
|
|
|
2795 /* The PNG data may have indicies packed in fewer than 8 bits, it
|
|
|
2796 * must be expanded if so.
|
|
|
2797 */
|
|
|
2798 if (png_ptr->bit_depth < 8)
|
|
|
2799 png_set_packing(png_ptr);
|
|
|
2800 }
|
|
|
2801 break;
|
|
|
2802
|
|
|
2803 default:
|
|
|
2804 png_error(png_ptr, "invalid PNG color type");
|
|
|
2805 /*NOT REACHED*/
|
|
|
2806 break;
|
|
|
2807 }
|
|
|
2808
|
|
|
2809 /* Now deal with the output processing */
|
|
|
2810 if (expand_tRNS && png_ptr->num_trans > 0 &&
|
|
|
2811 (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) == 0)
|
|
|
2812 png_set_tRNS_to_alpha(png_ptr);
|
|
|
2813
|
|
|
2814 switch (data_encoding)
|
|
|
2815 {
|
|
|
2816 default:
|
|
|
2817 png_error(png_ptr, "bad data option (internal error)");
|
|
|
2818 break;
|
|
|
2819
|
|
|
2820 case P_sRGB:
|
|
|
2821 /* Change to 8-bit sRGB */
|
|
|
2822 png_set_alpha_mode_fixed(png_ptr, PNG_ALPHA_PNG, PNG_GAMMA_sRGB);
|
|
|
2823 /* FALL THROUGH */
|
|
|
2824
|
|
|
2825 case P_FILE:
|
|
|
2826 if (png_ptr->bit_depth > 8)
|
|
|
2827 png_set_scale_16(png_ptr);
|
|
|
2828 break;
|
|
|
2829 }
|
|
|
2830
|
|
|
2831 if (cmap_entries > 256 || cmap_entries > image->colormap_entries)
|
|
|
2832 png_error(png_ptr, "color map overflow (BAD internal error)");
|
|
|
2833
|
|
|
2834 image->colormap_entries = cmap_entries;
|
|
|
2835
|
|
|
2836 /* Double check using the recorded background index */
|
|
|
2837 switch (output_processing)
|
|
|
2838 {
|
|
|
2839 case PNG_CMAP_NONE:
|
|
|
2840 if (background_index != PNG_CMAP_NONE_BACKGROUND)
|
|
|
2841 goto bad_background;
|
|
|
2842 break;
|
|
|
2843
|
|
|
2844 case PNG_CMAP_GA:
|
|
|
2845 if (background_index != PNG_CMAP_GA_BACKGROUND)
|
|
|
2846 goto bad_background;
|
|
|
2847 break;
|
|
|
2848
|
|
|
2849 case PNG_CMAP_TRANS:
|
|
|
2850 if (background_index >= cmap_entries ||
|
|
|
2851 background_index != PNG_CMAP_TRANS_BACKGROUND)
|
|
|
2852 goto bad_background;
|
|
|
2853 break;
|
|
|
2854
|
|
|
2855 case PNG_CMAP_RGB:
|
|
|
2856 if (background_index != PNG_CMAP_RGB_BACKGROUND)
|
|
|
2857 goto bad_background;
|
|
|
2858 break;
|
|
|
2859
|
|
|
2860 case PNG_CMAP_RGB_ALPHA:
|
|
|
2861 if (background_index != PNG_CMAP_RGB_ALPHA_BACKGROUND)
|
|
|
2862 goto bad_background;
|
|
|
2863 break;
|
|
|
2864
|
|
|
2865 default:
|
|
|
2866 png_error(png_ptr, "bad processing option (internal error)");
|
|
|
2867
|
|
|
2868 bad_background:
|
|
|
2869 png_error(png_ptr, "bad background index (internal error)");
|
|
|
2870 }
|
|
|
2871
|
|
|
2872 display->colormap_processing = output_processing;
|
|
|
2873
|
|
|
2874 return 1/*ok*/;
|
|
|
2875 }
|
|
|
2876
|
|
|
2877 /* The final part of the color-map read called from png_image_finish_read. */
|
|
|
2878 static int
|
|
|
2879 png_image_read_and_map(png_voidp argument)
|
|
|
2880 {
|
|
|
2881 png_image_read_control *display = png_voidcast(png_image_read_control*,
|
|
|
2882 argument);
|
|
|
2883 png_imagep image = display->image;
|
|
|
2884 png_structrp png_ptr = image->opaque->png_ptr;
|
|
|
2885 int passes;
|
|
|
2886
|
|
|
2887 /* Called when the libpng data must be transformed into the color-mapped
|
|
|
2888 * form. There is a local row buffer in display->local and this routine must
|
|
|
2889 * do the interlace handling.
|
|
|
2890 */
|
|
|
2891 switch (png_ptr->interlaced)
|
|
|
2892 {
|
|
|
2893 case PNG_INTERLACE_NONE:
|
|
|
2894 passes = 1;
|
|
|
2895 break;
|
|
|
2896
|
|
|
2897 case PNG_INTERLACE_ADAM7:
|
|
|
2898 passes = PNG_INTERLACE_ADAM7_PASSES;
|
|
|
2899 break;
|
|
|
2900
|
|
|
2901 default:
|
|
|
2902 png_error(png_ptr, "unknown interlace type");
|
|
|
2903 }
|
|
|
2904
|
|
|
2905 {
|
|
|
2906 png_uint_32 height = image->height;
|
|
|
2907 png_uint_32 width = image->width;
|
|
|
2908 int proc = display->colormap_processing;
|
|
|
2909 png_bytep first_row = png_voidcast(png_bytep, display->first_row);
|
|
|
2910 ptrdiff_t step_row = display->row_bytes;
|
|
|
2911 int pass;
|
|
|
2912
|
|
|
2913 for (pass = 0; pass < passes; ++pass)
|
|
|
2914 {
|
|
|
2915 unsigned int startx, stepx, stepy;
|
|
|
2916 png_uint_32 y;
|
|
|
2917
|
|
|
2918 if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
|
|
|
2919 {
|
|
|
2920 /* The row may be empty for a short image: */
|
|
|
2921 if (PNG_PASS_COLS(width, pass) == 0)
|
|
|
2922 continue;
|
|
|
2923
|
|
|
2924 startx = PNG_PASS_START_COL(pass);
|
|
|
2925 stepx = PNG_PASS_COL_OFFSET(pass);
|
|
|
2926 y = PNG_PASS_START_ROW(pass);
|
|
|
2927 stepy = PNG_PASS_ROW_OFFSET(pass);
|
|
|
2928 }
|
|
|
2929
|
|
|
2930 else
|
|
|
2931 {
|
|
|
2932 y = 0;
|
|
|
2933 startx = 0;
|
|
|
2934 stepx = stepy = 1;
|
|
|
2935 }
|
|
|
2936
|
|
|
2937 for (; y<height; y += stepy)
|
|
|
2938 {
|
|
|
2939 png_bytep inrow = png_voidcast(png_bytep, display->local_row);
|
|
|
2940 png_bytep outrow = first_row + y * step_row;
|
|
|
2941 png_const_bytep end_row = outrow + width;
|
|
|
2942
|
|
|
2943 /* Read read the libpng data into the temporary buffer. */
|
|
|
2944 png_read_row(png_ptr, inrow, NULL);
|
|
|
2945
|
|
|
2946 /* Now process the row according to the processing option, note
|
|
|
2947 * that the caller verifies that the format of the libpng output
|
|
|
2948 * data is as required.
|
|
|
2949 */
|
|
|
2950 outrow += startx;
|
|
|
2951 switch (proc)
|
|
|
2952 {
|
|
|
2953 case PNG_CMAP_GA:
|
|
|
2954 for (; outrow < end_row; outrow += stepx)
|
|
|
2955 {
|
|
|
2956 /* The data is always in the PNG order */
|
|
|
2957 unsigned int gray = *inrow++;
|
|
|
2958 unsigned int alpha = *inrow++;
|
|
|
2959 unsigned int entry;
|
|
|
2960
|
|
|
2961 /* NOTE: this code is copied as a comment in
|
|
|
2962 * make_ga_colormap above. Please update the
|
|
|
2963 * comment if you change this code!
|
|
|
2964 */
|
|
|
2965 if (alpha > 229) /* opaque */
|
|
|
2966 {
|
|
|
2967 entry = (231 * gray + 128) >> 8;
|
|
|
2968 }
|
|
|
2969 else if (alpha < 26) /* transparent */
|
|
|
2970 {
|
|
|
2971 entry = 231;
|
|
|
2972 }
|
|
|
2973 else /* partially opaque */
|
|
|
2974 {
|
|
|
2975 entry = 226 + 6 * PNG_DIV51(alpha) + PNG_DIV51(gray);
|
|
|
2976 }
|
|
|
2977
|
|
|
2978 *outrow = (png_byte)entry;
|
|
|
2979 }
|
|
|
2980 break;
|
|
|
2981
|
|
|
2982 case PNG_CMAP_TRANS:
|
|
|
2983 for (; outrow < end_row; outrow += stepx)
|
|
|
2984 {
|
|
|
2985 png_byte gray = *inrow++;
|
|
|
2986 png_byte alpha = *inrow++;
|
|
|
2987
|
|
|
2988 if (alpha == 0)
|
|
|
2989 *outrow = PNG_CMAP_TRANS_BACKGROUND;
|
|
|
2990
|
|
|
2991 else if (gray != PNG_CMAP_TRANS_BACKGROUND)
|
|
|
2992 *outrow = gray;
|
|
|
2993
|
|
|
2994 else
|
|
|
2995 *outrow = (png_byte)(PNG_CMAP_TRANS_BACKGROUND+1);
|
|
|
2996 }
|
|
|
2997 break;
|
|
|
2998
|
|
|
2999 case PNG_CMAP_RGB:
|
|
|
3000 for (; outrow < end_row; outrow += stepx)
|
|
|
3001 {
|
|
|
3002 *outrow = PNG_RGB_INDEX(inrow[0], inrow[1], inrow[2]);
|
|
|
3003 inrow += 3;
|
|
|
3004 }
|
|
|
3005 break;
|
|
|
3006
|
|
|
3007 case PNG_CMAP_RGB_ALPHA:
|
|
|
3008 for (; outrow < end_row; outrow += stepx)
|
|
|
3009 {
|
|
|
3010 unsigned int alpha = inrow[3];
|
|
|
3011
|
|
|
3012 /* Because the alpha entries only hold alpha==0.5 values
|
|
|
3013 * split the processing at alpha==0.25 (64) and 0.75
|
|
|
3014 * (196).
|
|
|
3015 */
|
|
|
3016
|
|
|
3017 if (alpha >= 196)
|
|
|
3018 *outrow = PNG_RGB_INDEX(inrow[0], inrow[1],
|
|
|
3019 inrow[2]);
|
|
|
3020
|
|
|
3021 else if (alpha < 64)
|
|
|
3022 *outrow = PNG_CMAP_RGB_ALPHA_BACKGROUND;
|
|
|
3023
|
|
|
3024 else
|
|
|
3025 {
|
|
|
3026 /* Likewise there are three entries for each of r, g
|
|
|
3027 * and b. We could select the entry by popcount on
|
|
|
3028 * the top two bits on those architectures that
|
|
|
3029 * support it, this is what the code below does,
|
|
|
3030 * crudely.
|
|
|
3031 */
|
|
|
3032 unsigned int back_i = PNG_CMAP_RGB_ALPHA_BACKGROUND+1;
|
|
|
3033
|
|
|
3034 /* Here are how the values map:
|
|
|
3035 *
|
|
|
3036 * 0x00 .. 0x3f -> 0
|
|
|
3037 * 0x40 .. 0xbf -> 1
|
|
|
3038 * 0xc0 .. 0xff -> 2
|
|
|
3039 *
|
|
|
3040 * So, as above with the explicit alpha checks, the
|
|
|
3041 * breakpoints are at 64 and 196.
|
|
|
3042 */
|
|
|
3043 if (inrow[0] & 0x80) back_i += 9; /* red */
|
|
|
3044 if (inrow[0] & 0x40) back_i += 9;
|
|
|
3045 if (inrow[0] & 0x80) back_i += 3; /* green */
|
|
|
3046 if (inrow[0] & 0x40) back_i += 3;
|
|
|
3047 if (inrow[0] & 0x80) back_i += 1; /* blue */
|
|
|
3048 if (inrow[0] & 0x40) back_i += 1;
|
|
|
3049
|
|
|
3050 *outrow = (png_byte)back_i;
|
|
|
3051 }
|
|
|
3052
|
|
|
3053 inrow += 4;
|
|
|
3054 }
|
|
|
3055 break;
|
|
|
3056
|
|
|
3057 default:
|
|
|
3058 break;
|
|
|
3059 }
|
|
|
3060 }
|
|
|
3061 }
|
|
|
3062 }
|
|
|
3063
|
|
|
3064 return 1;
|
|
|
3065 }
|
|
|
3066
|
|
|
3067 static int
|
|
|
3068 png_image_read_colormapped(png_voidp argument)
|
|
|
3069 {
|
|
|
3070 png_image_read_control *display = png_voidcast(png_image_read_control*,
|
|
|
3071 argument);
|
|
|
3072 png_imagep image = display->image;
|
|
|
3073 png_controlp control = image->opaque;
|
|
|
3074 png_structrp png_ptr = control->png_ptr;
|
|
|
3075 png_inforp info_ptr = control->info_ptr;
|
|
|
3076
|
|
|
3077 int passes = 0; /* As a flag */
|
|
|
3078
|
|
|
3079 PNG_SKIP_CHUNKS(png_ptr);
|
|
|
3080
|
|
|
3081 /* Update the 'info' structure and make sure the result is as required; first
|
|
|
3082 * make sure to turn on the interlace handling if it will be required
|
|
|
3083 * (because it can't be turned on *after* the call to png_read_update_info!)
|
|
|
3084 */
|
|
|
3085 if (display->colormap_processing == PNG_CMAP_NONE)
|
|
|
3086 passes = png_set_interlace_handling(png_ptr);
|
|
|
3087
|
|
|
3088 png_read_update_info(png_ptr, info_ptr);
|
|
|
3089
|
|
|
3090 /* The expected output can be deduced from the colormap_processing option. */
|
|
|
3091 switch (display->colormap_processing)
|
|
|
3092 {
|
|
|
3093 case PNG_CMAP_NONE:
|
|
|
3094 /* Output must be one channel and one byte per pixel, the output
|
|
|
3095 * encoding can be anything.
|
|
|
3096 */
|
|
|
3097 if ((info_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||
|
|
|
3098 info_ptr->color_type == PNG_COLOR_TYPE_GRAY) &&
|
|
|
3099 info_ptr->bit_depth == 8)
|
|
|
3100 break;
|
|
|
3101
|
|
|
3102 goto bad_output;
|
|
|
3103
|
|
|
3104 case PNG_CMAP_TRANS:
|
|
|
3105 case PNG_CMAP_GA:
|
|
|
3106 /* Output must be two channels and the 'G' one must be sRGB, the latter
|
|
|
3107 * can be checked with an exact number because it should have been set
|
|
|
3108 * to this number above!
|
|
|
3109 */
|
|
|
3110 if (info_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA &&
|
|
|
3111 info_ptr->bit_depth == 8 &&
|
|
|
3112 png_ptr->screen_gamma == PNG_GAMMA_sRGB &&
|
|
|
3113 image->colormap_entries == 256)
|
|
|
3114 break;
|
|
|
3115
|
|
|
3116 goto bad_output;
|
|
|
3117
|
|
|
3118 case PNG_CMAP_RGB:
|
|
|
3119 /* Output must be 8-bit sRGB encoded RGB */
|
|
|
3120 if (info_ptr->color_type == PNG_COLOR_TYPE_RGB &&
|
|
|
3121 info_ptr->bit_depth == 8 &&
|
|
|
3122 png_ptr->screen_gamma == PNG_GAMMA_sRGB &&
|
|
|
3123 image->colormap_entries == 216)
|
|
|
3124 break;
|
|
|
3125
|
|
|
3126 goto bad_output;
|
|
|
3127
|
|
|
3128 case PNG_CMAP_RGB_ALPHA:
|
|
|
3129 /* Output must be 8-bit sRGB encoded RGBA */
|
|
|
3130 if (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
|
|
|
3131 info_ptr->bit_depth == 8 &&
|
|
|
3132 png_ptr->screen_gamma == PNG_GAMMA_sRGB &&
|
|
|
3133 image->colormap_entries == 244 /* 216 + 1 + 27 */)
|
|
|
3134 break;
|
|
|
3135
|
|
|
3136 /* goto bad_output; */
|
|
|
3137 /* FALL THROUGH */
|
|
|
3138
|
|
|
3139 default:
|
|
|
3140 bad_output:
|
|
|
3141 png_error(png_ptr, "bad color-map processing (internal error)");
|
|
|
3142 }
|
|
|
3143
|
|
|
3144 /* Now read the rows. Do this here if it is possible to read directly into
|
|
|
3145 * the output buffer, otherwise allocate a local row buffer of the maximum
|
|
|
3146 * size libpng requires and call the relevant processing routine safely.
|
|
|
3147 */
|
|
|
3148 {
|
|
|
3149 png_voidp first_row = display->buffer;
|
|
|
3150 ptrdiff_t row_bytes = display->row_stride;
|
|
|
3151
|
|
|
3152 /* The following expression is designed to work correctly whether it gives
|
|
|
3153 * a signed or an unsigned result.
|
|
|
3154 */
|
|
|
3155 if (row_bytes < 0)
|
|
|
3156 {
|
|
|
3157 char *ptr = png_voidcast(char*, first_row);
|
|
|
3158 ptr += (image->height-1) * (-row_bytes);
|
|
|
3159 first_row = png_voidcast(png_voidp, ptr);
|
|
|
3160 }
|
|
|
3161
|
|
|
3162 display->first_row = first_row;
|
|
|
3163 display->row_bytes = row_bytes;
|
|
|
3164 }
|
|
|
3165
|
|
|
3166 if (passes == 0)
|
|
|
3167 {
|
|
|
3168 int result;
|
|
|
3169 png_voidp row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr));
|
|
|
3170
|
|
|
3171 display->local_row = row;
|
|
|
3172 result = png_safe_execute(image, png_image_read_and_map, display);
|
|
|
3173 display->local_row = NULL;
|
|
|
3174 png_free(png_ptr, row);
|
|
|
3175
|
|
|
3176 return result;
|
|
|
3177 }
|
|
|
3178
|
|
|
3179 else
|
|
|
3180 {
|
|
|
3181 png_alloc_size_t row_bytes = display->row_bytes;
|
|
|
3182
|
|
|
3183 while (--passes >= 0)
|
|
|
3184 {
|
|
|
3185 png_uint_32 y = image->height;
|
|
|
3186 png_bytep row = png_voidcast(png_bytep, display->first_row);
|
|
|
3187
|
|
|
3188 while (y-- > 0)
|
|
|
3189 {
|
|
|
3190 png_read_row(png_ptr, row, NULL);
|
|
|
3191 row += row_bytes;
|
|
|
3192 }
|
|
|
3193 }
|
|
|
3194
|
|
|
3195 return 1;
|
|
|
3196 }
|
|
|
3197 }
|
|
|
3198
|
|
|
3199 /* Just the row reading part of png_image_read. */
|
|
|
3200 static int
|
|
|
3201 png_image_read_composite(png_voidp argument)
|
|
|
3202 {
|
|
|
3203 png_image_read_control *display = png_voidcast(png_image_read_control*,
|
|
|
3204 argument);
|
|
|
3205 png_imagep image = display->image;
|
|
|
3206 png_structrp png_ptr = image->opaque->png_ptr;
|
|
|
3207 int passes;
|
|
|
3208
|
|
|
3209 switch (png_ptr->interlaced)
|
|
|
3210 {
|
|
|
3211 case PNG_INTERLACE_NONE:
|
|
|
3212 passes = 1;
|
|
|
3213 break;
|
|
|
3214
|
|
|
3215 case PNG_INTERLACE_ADAM7:
|
|
|
3216 passes = PNG_INTERLACE_ADAM7_PASSES;
|
|
|
3217 break;
|
|
|
3218
|
|
|
3219 default:
|
|
|
3220 png_error(png_ptr, "unknown interlace type");
|
|
|
3221 }
|
|
|
3222
|
|
|
3223 {
|
|
|
3224 png_uint_32 height = image->height;
|
|
|
3225 png_uint_32 width = image->width;
|
|
|
3226 ptrdiff_t step_row = display->row_bytes;
|
|
|
3227 unsigned int channels = (image->format & PNG_FORMAT_FLAG_COLOR) ? 3 : 1;
|
|
|
3228 int pass;
|
|
|
3229
|
|
|
3230 for (pass = 0; pass < passes; ++pass)
|
|
|
3231 {
|
|
|
3232 unsigned int startx, stepx, stepy;
|
|
|
3233 png_uint_32 y;
|
|
|
3234
|
|
|
3235 if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
|
|
|
3236 {
|
|
|
3237 /* The row may be empty for a short image: */
|
|
|
3238 if (PNG_PASS_COLS(width, pass) == 0)
|
|
|
3239 continue;
|
|
|
3240
|
|
|
3241 startx = PNG_PASS_START_COL(pass) * channels;
|
|
|
3242 stepx = PNG_PASS_COL_OFFSET(pass) * channels;
|
|
|
3243 y = PNG_PASS_START_ROW(pass);
|
|
|
3244 stepy = PNG_PASS_ROW_OFFSET(pass);
|
|
|
3245 }
|
|
|
3246
|
|
|
3247 else
|
|
|
3248 {
|
|
|
3249 y = 0;
|
|
|
3250 startx = 0;
|
|
|
3251 stepx = channels;
|
|
|
3252 stepy = 1;
|
|
|
3253 }
|
|
|
3254
|
|
|
3255 for (; y<height; y += stepy)
|
|
|
3256 {
|
|
|
3257 png_bytep inrow = png_voidcast(png_bytep, display->local_row);
|
|
|
3258 png_bytep outrow;
|
|
|
3259 png_const_bytep end_row;
|
|
|
3260
|
|
|
3261 /* Read the row, which is packed: */
|
|
|
3262 png_read_row(png_ptr, inrow, NULL);
|
|
|
3263
|
|
|
3264 outrow = png_voidcast(png_bytep, display->first_row);
|
|
|
3265 outrow += y * step_row;
|
|
|
3266 end_row = outrow + width * channels;
|
|
|
3267
|
|
|
3268 /* Now do the composition on each pixel in this row. */
|
|
|
3269 outrow += startx;
|
|
|
3270 for (; outrow < end_row; outrow += stepx)
|
|
|
3271 {
|
|
|
3272 png_byte alpha = inrow[channels];
|
|
|
3273
|
|
|
3274 if (alpha > 0) /* else no change to the output */
|
|
|
3275 {
|
|
|
3276 unsigned int c;
|
|
|
3277
|
|
|
3278 for (c=0; c<channels; ++c)
|
|
|
3279 {
|
|
|
3280 png_uint_32 component = inrow[c];
|
|
|
3281
|
|
|
3282 if (alpha < 255) /* else just use component */
|
|
|
3283 {
|
|
|
3284 /* This is PNG_OPTIMIZED_ALPHA, the component value
|
|
|
3285 * is a linear 8-bit value. Combine this with the
|
|
|
3286 * current outrow[c] value which is sRGB encoded.
|
|
|
3287 * Arithmetic here is 16-bits to preserve the output
|
|
|
3288 * values correctly.
|
|
|
3289 */
|
|
|
3290 component *= 257*255; /* =65535 */
|
|
|
3291 component += (255-alpha)*png_sRGB_table[outrow[c]];
|
|
|
3292
|
|
|
3293 /* So 'component' is scaled by 255*65535 and is
|
|
|
3294 * therefore appropriate for the sRGB to linear
|
|
|
3295 * conversion table.
|
|
|
3296 */
|
|
|
3297 component = PNG_sRGB_FROM_LINEAR(component);
|
|
|
3298 }
|
|
|
3299
|
|
|
3300 outrow[c] = (png_byte)component;
|
|
|
3301 }
|
|
|
3302 }
|
|
|
3303
|
|
|
3304 inrow += channels+1; /* components and alpha channel */
|
|
|
3305 }
|
|
|
3306 }
|
|
|
3307 }
|
|
|
3308 }
|
|
|
3309
|
|
|
3310 return 1;
|
|
|
3311 }
|
|
|
3312
|
|
|
3313 /* The do_local_background case; called when all the following transforms are to
|
|
|
3314 * be done:
|
|
|
3315 *
|
|
|
3316 * PNG_RGB_TO_GRAY
|
|
|
3317 * PNG_COMPOSITE
|
|
|
3318 * PNG_GAMMA
|
|
|
3319 *
|
|
|
3320 * This is a work-round for the fact that both the PNG_RGB_TO_GRAY and
|
|
|
3321 * PNG_COMPOSITE code performs gamma correction, so we get double gamma
|
|
|
3322 * correction. The fix-up is to prevent the PNG_COMPOSITE operation happening
|
|
|
3323 * inside libpng, so this routine sees an 8 or 16-bit gray+alpha row and handles
|
|
|
3324 * the removal or pre-multiplication of the alpha channel.
|
|
|
3325 */
|
|
|
3326 static int
|
|
|
3327 png_image_read_background(png_voidp argument)
|
|
|
3328 {
|
|
|
3329 png_image_read_control *display = png_voidcast(png_image_read_control*,
|
|
|
3330 argument);
|
|
|
3331 png_imagep image = display->image;
|
|
|
3332 png_structrp png_ptr = image->opaque->png_ptr;
|
|
|
3333 png_inforp info_ptr = image->opaque->info_ptr;
|
|
|
3334 png_uint_32 height = image->height;
|
|
|
3335 png_uint_32 width = image->width;
|
|
|
3336 int pass, passes;
|
|
|
3337
|
|
|
3338 /* Double check the convoluted logic below. We expect to get here with
|
|
|
3339 * libpng doing rgb to gray and gamma correction but background processing
|
|
|
3340 * left to the png_image_read_background function. The rows libpng produce
|
|
|
3341 * might be 8 or 16-bit but should always have two channels; gray plus alpha.
|
|
|
3342 */
|
|
|
3343 if ((png_ptr->transformations & PNG_RGB_TO_GRAY) == 0)
|
|
|
3344 png_error(png_ptr, "lost rgb to gray");
|
|
|
3345
|
|
|
3346 if ((png_ptr->transformations & PNG_COMPOSE) != 0)
|
|
|
3347 png_error(png_ptr, "unexpected compose");
|
|
|
3348
|
|
|
3349 if (png_get_channels(png_ptr, info_ptr) != 2)
|
|
|
3350 png_error(png_ptr, "lost/gained channels");
|
|
|
3351
|
|
|
3352 /* Expect the 8-bit case to always remove the alpha channel */
|
|
|
3353 if ((image->format & PNG_FORMAT_FLAG_LINEAR) == 0 &&
|
|
|
3354 (image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
|
|
|
3355 png_error(png_ptr, "unexpected 8-bit transformation");
|
|
|
3356
|
|
|
3357 switch (png_ptr->interlaced)
|
|
|
3358 {
|
|
|
3359 case PNG_INTERLACE_NONE:
|
|
|
3360 passes = 1;
|
|
|
3361 break;
|
|
|
3362
|
|
|
3363 case PNG_INTERLACE_ADAM7:
|
|
|
3364 passes = PNG_INTERLACE_ADAM7_PASSES;
|
|
|
3365 break;
|
|
|
3366
|
|
|
3367 default:
|
|
|
3368 png_error(png_ptr, "unknown interlace type");
|
|
|
3369 }
|
|
|
3370
|
|
|
3371 /* Use direct access to info_ptr here because otherwise the simplified API
|
|
|
3372 * would require PNG_EASY_ACCESS_SUPPORTED (just for this.) Note this is
|
|
|
3373 * checking the value after libpng expansions, not the original value in the
|
|
|
3374 * PNG.
|
|
|
3375 */
|
|
|
3376 switch (info_ptr->bit_depth)
|
|
|
3377 {
|
|
|
3378 default:
|
|
|
3379 png_error(png_ptr, "unexpected bit depth");
|
|
|
3380 break;
|
|
|
3381
|
|
|
3382 case 8:
|
|
|
3383 /* 8-bit sRGB gray values with an alpha channel; the alpha channel is
|
|
|
3384 * to be removed by composing on a background: either the row if
|
|
|
3385 * display->background is NULL or display->background->green if not.
|
|
|
3386 * Unlike the code above ALPHA_OPTIMIZED has *not* been done.
|
|
|
3387 */
|
|
|
3388 {
|
|
|
3389 png_bytep first_row = png_voidcast(png_bytep, display->first_row);
|
|
|
3390 ptrdiff_t step_row = display->row_bytes;
|
|
|
3391
|
|
|
3392 for (pass = 0; pass < passes; ++pass)
|
|
|
3393 {
|
|
|
3394 png_bytep row = png_voidcast(png_bytep,
|
|
|
3395 display->first_row);
|
|
|
3396 unsigned int startx, stepx, stepy;
|
|
|
3397 png_uint_32 y;
|
|
|
3398
|
|
|
3399 if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
|
|
|
3400 {
|
|
|
3401 /* The row may be empty for a short image: */
|
|
|
3402 if (PNG_PASS_COLS(width, pass) == 0)
|
|
|
3403 continue;
|
|
|
3404
|
|
|
3405 startx = PNG_PASS_START_COL(pass);
|
|
|
3406 stepx = PNG_PASS_COL_OFFSET(pass);
|
|
|
3407 y = PNG_PASS_START_ROW(pass);
|
|
|
3408 stepy = PNG_PASS_ROW_OFFSET(pass);
|
|
|
3409 }
|
|
|
3410
|
|
|
3411 else
|
|
|
3412 {
|
|
|
3413 y = 0;
|
|
|
3414 startx = 0;
|
|
|
3415 stepx = stepy = 1;
|
|
|
3416 }
|
|
|
3417
|
|
|
3418 if (display->background == NULL)
|
|
|
3419 {
|
|
|
3420 for (; y<height; y += stepy)
|
|
|
3421 {
|
|
|
3422 png_bytep inrow = png_voidcast(png_bytep,
|
|
|
3423 display->local_row);
|
|
|
3424 png_bytep outrow = first_row + y * step_row;
|
|
|
3425 png_const_bytep end_row = outrow + width;
|
|
|
3426
|
|
|
3427 /* Read the row, which is packed: */
|
|
|
3428 png_read_row(png_ptr, inrow, NULL);
|
|
|
3429
|
|
|
3430 /* Now do the composition on each pixel in this row. */
|
|
|
3431 outrow += startx;
|
|
|
3432 for (; outrow < end_row; outrow += stepx)
|
|
|
3433 {
|
|
|
3434 png_byte alpha = inrow[1];
|
|
|
3435
|
|
|
3436 if (alpha > 0) /* else no change to the output */
|
|
|
3437 {
|
|
|
3438 png_uint_32 component = inrow[0];
|
|
|
3439
|
|
|
3440 if (alpha < 255) /* else just use component */
|
|
|
3441 {
|
|
|
3442 /* Since PNG_OPTIMIZED_ALPHA was not set it is
|
|
|
3443 * necessary to invert the sRGB transfer
|
|
|
3444 * function and multiply the alpha out.
|
|
|
3445 */
|
|
|
3446 component = png_sRGB_table[component] * alpha;
|
|
|
3447 component += png_sRGB_table[outrow[0]] *
|
|
|
3448 (255-alpha);
|
|
|
3449 component = PNG_sRGB_FROM_LINEAR(component);
|
|
|
3450 }
|
|
|
3451
|
|
|
3452 outrow[0] = (png_byte)component;
|
|
|
3453 }
|
|
|
3454
|
|
|
3455 inrow += 2; /* gray and alpha channel */
|
|
|
3456 }
|
|
|
3457 }
|
|
|
3458 }
|
|
|
3459
|
|
|
3460 else /* constant background value */
|
|
|
3461 {
|
|
|
3462 png_byte background8 = display->background->green;
|
|
|
3463 png_uint_16 background = png_sRGB_table[background8];
|
|
|
3464
|
|
|
3465 for (; y<height; y += stepy)
|
|
|
3466 {
|
|
|
3467 png_bytep inrow = png_voidcast(png_bytep,
|
|
|
3468 display->local_row);
|
|
|
3469 png_bytep outrow = first_row + y * step_row;
|
|
|
3470 png_const_bytep end_row = outrow + width;
|
|
|
3471
|
|
|
3472 /* Read the row, which is packed: */
|
|
|
3473 png_read_row(png_ptr, inrow, NULL);
|
|
|
3474
|
|
|
3475 /* Now do the composition on each pixel in this row. */
|
|
|
3476 outrow += startx;
|
|
|
3477 for (; outrow < end_row; outrow += stepx)
|
|
|
3478 {
|
|
|
3479 png_byte alpha = inrow[1];
|
|
|
3480
|
|
|
3481 if (alpha > 0) /* else use background */
|
|
|
3482 {
|
|
|
3483 png_uint_32 component = inrow[0];
|
|
|
3484
|
|
|
3485 if (alpha < 255) /* else just use component */
|
|
|
3486 {
|
|
|
3487 component = png_sRGB_table[component] * alpha;
|
|
|
3488 component += background * (255-alpha);
|
|
|
3489 component = PNG_sRGB_FROM_LINEAR(component);
|
|
|
3490 }
|
|
|
3491
|
|
|
3492 outrow[0] = (png_byte)component;
|
|
|
3493 }
|
|
|
3494
|
|
|
3495 else
|
|
|
3496 outrow[0] = background8;
|
|
|
3497
|
|
|
3498 inrow += 2; /* gray and alpha channel */
|
|
|
3499 }
|
|
|
3500
|
|
|
3501 row += display->row_bytes;
|
|
|
3502 }
|
|
|
3503 }
|
|
|
3504 }
|
|
|
3505 }
|
|
|
3506 break;
|
|
|
3507
|
|
|
3508 case 16:
|
|
|
3509 /* 16-bit linear with pre-multiplied alpha; the pre-multiplication must
|
|
|
3510 * still be done and, maybe, the alpha channel removed. This code also
|
|
|
3511 * handles the alpha-first option.
|
|
|
3512 */
|
|
|
3513 {
|
|
|
3514 png_uint_16p first_row = png_voidcast(png_uint_16p,
|
|
|
3515 display->first_row);
|
|
|
3516 /* The division by two is safe because the caller passed in a
|
|
|
3517 * stride which was multiplied by 2 (below) to get row_bytes.
|
|
|
3518 */
|
|
|
3519 ptrdiff_t step_row = display->row_bytes / 2;
|
|
|
3520 int preserve_alpha = (image->format & PNG_FORMAT_FLAG_ALPHA) != 0;
|
|
|
3521 unsigned int outchannels = 1+preserve_alpha;
|
|
|
3522 int swap_alpha = 0;
|
|
|
3523
|
|
|
3524 # ifdef PNG_SIMPLIFIED_READ_AFIRST_SUPPORTED
|
|
|
3525 if (preserve_alpha && (image->format & PNG_FORMAT_FLAG_AFIRST))
|
|
|
3526 swap_alpha = 1;
|
|
|
3527 # endif
|
|
|
3528
|
|
|
3529 for (pass = 0; pass < passes; ++pass)
|
|
|
3530 {
|
|
|
3531 unsigned int startx, stepx, stepy;
|
|
|
3532 png_uint_32 y;
|
|
|
3533
|
|
|
3534 /* The 'x' start and step are adjusted to output components here.
|
|
|
3535 */
|
|
|
3536 if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
|
|
|
3537 {
|
|
|
3538 /* The row may be empty for a short image: */
|
|
|
3539 if (PNG_PASS_COLS(width, pass) == 0)
|
|
|
3540 continue;
|
|
|
3541
|
|
|
3542 startx = PNG_PASS_START_COL(pass) * outchannels;
|
|
|
3543 stepx = PNG_PASS_COL_OFFSET(pass) * outchannels;
|
|
|
3544 y = PNG_PASS_START_ROW(pass);
|
|
|
3545 stepy = PNG_PASS_ROW_OFFSET(pass);
|
|
|
3546 }
|
|
|
3547
|
|
|
3548 else
|
|
|
3549 {
|
|
|
3550 y = 0;
|
|
|
3551 startx = 0;
|
|
|
3552 stepx = outchannels;
|
|
|
3553 stepy = 1;
|
|
|
3554 }
|
|
|
3555
|
|
|
3556 for (; y<height; y += stepy)
|
|
|
3557 {
|
|
|
3558 png_const_uint_16p inrow;
|
|
|
3559 png_uint_16p outrow = first_row + y*step_row;
|
|
|
3560 png_uint_16p end_row = outrow + width * outchannels;
|
|
|
3561
|
|
|
3562 /* Read the row, which is packed: */
|
|
|
3563 png_read_row(png_ptr, png_voidcast(png_bytep,
|
|
|
3564 display->local_row), NULL);
|
|
|
3565 inrow = png_voidcast(png_const_uint_16p, display->local_row);
|
|
|
3566
|
|
|
3567 /* Now do the pre-multiplication on each pixel in this row.
|
|
|
3568 */
|
|
|
3569 outrow += startx;
|
|
|
3570 for (; outrow < end_row; outrow += stepx)
|
|
|
3571 {
|
|
|
3572 png_uint_32 component = inrow[0];
|
|
|
3573 png_uint_16 alpha = inrow[1];
|
|
|
3574
|
|
|
3575 if (alpha > 0) /* else 0 */
|
|
|
3576 {
|
|
|
3577 if (alpha < 65535) /* else just use component */
|
|
|
3578 {
|
|
|
3579 component *= alpha;
|
|
|
3580 component += 32767;
|
|
|
3581 component /= 65535;
|
|
|
3582 }
|
|
|
3583 }
|
|
|
3584
|
|
|
3585 else
|
|
|
3586 component = 0;
|
|
|
3587
|
|
|
3588 outrow[swap_alpha] = (png_uint_16)component;
|
|
|
3589 if (preserve_alpha)
|
|
|
3590 outrow[1 ^ swap_alpha] = alpha;
|
|
|
3591
|
|
|
3592 inrow += 2; /* components and alpha channel */
|
|
|
3593 }
|
|
|
3594 }
|
|
|
3595 }
|
|
|
3596 }
|
|
|
3597 break;
|
|
|
3598 }
|
|
|
3599
|
|
|
3600 return 1;
|
|
|
3601 }
|
|
|
3602
|
|
|
3603 /* The guts of png_image_finish_read as a png_safe_execute callback. */
|
|
|
3604 static int
|
|
|
3605 png_image_read_direct(png_voidp argument)
|
|
|
3606 {
|
|
|
3607 png_image_read_control *display = png_voidcast(png_image_read_control*,
|
|
|
3608 argument);
|
|
|
3609 png_imagep image = display->image;
|
|
|
3610 png_structrp png_ptr = image->opaque->png_ptr;
|
|
|
3611 png_inforp info_ptr = image->opaque->info_ptr;
|
|
|
3612
|
|
|
3613 png_uint_32 format = image->format;
|
|
|
3614 int linear = (format & PNG_FORMAT_FLAG_LINEAR) != 0;
|
|
|
3615 int do_local_compose = 0;
|
|
|
3616 int do_local_background = 0; /* to avoid double gamma correction bug */
|
|
|
3617 int passes = 0;
|
|
|
3618
|
|
|
3619 /* Add transforms to ensure the correct output format is produced then check
|
|
|
3620 * that the required implementation support is there. Always expand; always
|
|
|
3621 * need 8 bits minimum, no palette and expanded tRNS.
|
|
|
3622 */
|
|
|
3623 png_set_expand(png_ptr);
|
|
|
3624
|
|
|
3625 /* Now check the format to see if it was modified. */
|
|
|
3626 {
|
|
|
3627 png_uint_32 base_format = png_image_format(png_ptr) &
|
|
|
3628 ~PNG_FORMAT_FLAG_COLORMAP /* removed by png_set_expand */;
|
|
|
3629 png_uint_32 change = format ^ base_format;
|
|
|
3630 png_fixed_point output_gamma;
|
|
|
3631 int mode; /* alpha mode */
|
|
|
3632
|
|
|
3633 /* Do this first so that we have a record if rgb to gray is happening. */
|
|
|
3634 if (change & PNG_FORMAT_FLAG_COLOR)
|
|
|
3635 {
|
|
|
3636 /* gray<->color transformation required. */
|
|
|
3637 if (format & PNG_FORMAT_FLAG_COLOR)
|
|
|
3638 png_set_gray_to_rgb(png_ptr);
|
|
|
3639
|
|
|
3640 else
|
|
|
3641 {
|
|
|
3642 /* libpng can't do both rgb to gray and
|
|
|
3643 * background/pre-multiplication if there is also significant gamma
|
|
|
3644 * correction, because both operations require linear colors and
|
|
|
3645 * the code only supports one transform doing the gamma correction.
|
|
|
3646 * Handle this by doing the pre-multiplication or background
|
|
|
3647 * operation in this code, if necessary.
|
|
|
3648 *
|
|
|
3649 * TODO: fix this by rewriting pngrtran.c (!)
|
|
|
3650 *
|
|
|
3651 * For the moment (given that fixing this in pngrtran.c is an
|
|
|
3652 * enormous change) 'do_local_background' is used to indicate that
|
|
|
3653 * the problem exists.
|
|
|
3654 */
|
|
|
3655 if (base_format & PNG_FORMAT_FLAG_ALPHA)
|
|
|
3656 do_local_background = 1/*maybe*/;
|
|
|
3657
|
|
|
3658 png_set_rgb_to_gray_fixed(png_ptr, PNG_ERROR_ACTION_NONE,
|
|
|
3659 PNG_RGB_TO_GRAY_DEFAULT, PNG_RGB_TO_GRAY_DEFAULT);
|
|
|
3660 }
|
|
|
3661
|
|
|
3662 change &= ~PNG_FORMAT_FLAG_COLOR;
|
|
|
3663 }
|
|
|
3664
|
|
|
3665 /* Set the gamma appropriately, linear for 16-bit input, sRGB otherwise.
|
|
|
3666 */
|
|
|
3667 {
|
|
|
3668 png_fixed_point input_gamma_default;
|
|
|
3669
|
|
|
3670 if ((base_format & PNG_FORMAT_FLAG_LINEAR) &&
|
|
|
3671 (image->flags & PNG_IMAGE_FLAG_16BIT_sRGB) == 0)
|
|
|
3672 input_gamma_default = PNG_GAMMA_LINEAR;
|
|
|
3673 else
|
|
|
3674 input_gamma_default = PNG_DEFAULT_sRGB;
|
|
|
3675
|
|
|
3676 /* Call png_set_alpha_mode to set the default for the input gamma; the
|
|
|
3677 * output gamma is set by a second call below.
|
|
|
3678 */
|
|
|
3679 png_set_alpha_mode_fixed(png_ptr, PNG_ALPHA_PNG, input_gamma_default);
|
|
|
3680 }
|
|
|
3681
|
|
|
3682 if (linear)
|
|
|
3683 {
|
|
|
3684 /* If there *is* an alpha channel in the input it must be multiplied
|
|
|
3685 * out; use PNG_ALPHA_STANDARD, otherwise just use PNG_ALPHA_PNG.
|
|
|
3686 */
|
|
|
3687 if (base_format & PNG_FORMAT_FLAG_ALPHA)
|
|
|
3688 mode = PNG_ALPHA_STANDARD; /* associated alpha */
|
|
|
3689
|
|
|
3690 else
|
|
|
3691 mode = PNG_ALPHA_PNG;
|
|
|
3692
|
|
|
3693 output_gamma = PNG_GAMMA_LINEAR;
|
|
|
3694 }
|
|
|
3695
|
|
|
3696 else
|
|
|
3697 {
|
|
|
3698 mode = PNG_ALPHA_PNG;
|
|
|
3699 output_gamma = PNG_DEFAULT_sRGB;
|
|
|
3700 }
|
|
|
3701
|
|
|
3702 /* If 'do_local_background' is set check for the presence of gamma
|
|
|
3703 * correction; this is part of the work-round for the libpng bug
|
|
|
3704 * described above.
|
|
|
3705 *
|
|
|
3706 * TODO: fix libpng and remove this.
|
|
|
3707 */
|
|
|
3708 if (do_local_background)
|
|
|
3709 {
|
|
|
3710 png_fixed_point gtest;
|
|
|
3711
|
|
|
3712 /* This is 'png_gamma_threshold' from pngrtran.c; the test used for
|
|
|
3713 * gamma correction, the screen gamma hasn't been set on png_struct
|
|
|
3714 * yet; it's set below. png_struct::gamma, however, is set to the
|
|
|
3715 * final value.
|
|
|
3716 */
|
|
|
3717 if (png_muldiv(>est, output_gamma, png_ptr->colorspace.gamma,
|
|
|
3718 PNG_FP_1) && !png_gamma_significant(gtest))
|
|
|
3719 do_local_background = 0;
|
|
|
3720
|
|
|
3721 else if (mode == PNG_ALPHA_STANDARD)
|
|
|
3722 {
|
|
|
3723 do_local_background = 2/*required*/;
|
|
|
3724 mode = PNG_ALPHA_PNG; /* prevent libpng doing it */
|
|
|
3725 }
|
|
|
3726
|
|
|
3727 /* else leave as 1 for the checks below */
|
|
|
3728 }
|
|
|
3729
|
|
|
3730 /* If the bit-depth changes then handle that here. */
|
|
|
3731 if (change & PNG_FORMAT_FLAG_LINEAR)
|
|
|
3732 {
|
|
|
3733 if (linear /*16-bit output*/)
|
|
|
3734 png_set_expand_16(png_ptr);
|
|
|
3735
|
|
|
3736 else /* 8-bit output */
|
|
|
3737 png_set_scale_16(png_ptr);
|
|
|
3738
|
|
|
3739 change &= ~PNG_FORMAT_FLAG_LINEAR;
|
|
|
3740 }
|
|
|
3741
|
|
|
3742 /* Now the background/alpha channel changes. */
|
|
|
3743 if (change & PNG_FORMAT_FLAG_ALPHA)
|
|
|
3744 {
|
|
|
3745 /* Removing an alpha channel requires composition for the 8-bit
|
|
|
3746 * formats; for the 16-bit it is already done, above, by the
|
|
|
3747 * pre-multiplication and the channel just needs to be stripped.
|
|
|
3748 */
|
|
|
3749 if (base_format & PNG_FORMAT_FLAG_ALPHA)
|
|
|
3750 {
|
|
|
3751 /* If RGB->gray is happening the alpha channel must be left and the
|
|
|
3752 * operation completed locally.
|
|
|
3753 *
|
|
|
3754 * TODO: fix libpng and remove this.
|
|
|
3755 */
|
|
|
3756 if (do_local_background)
|
|
|
3757 do_local_background = 2/*required*/;
|
|
|
3758
|
|
|
3759 /* 16-bit output: just remove the channel */
|
|
|
3760 else if (linear) /* compose on black (well, pre-multiply) */
|
|
|
3761 png_set_strip_alpha(png_ptr);
|
|
|
3762
|
|
|
3763 /* 8-bit output: do an appropriate compose */
|
|
|
3764 else if (display->background != NULL)
|
|
|
3765 {
|
|
|
3766 png_color_16 c;
|
|
|
3767
|
|
|
3768 c.index = 0; /*unused*/
|
|
|
3769 c.red = display->background->red;
|
|
|
3770 c.green = display->background->green;
|
|
|
3771 c.blue = display->background->blue;
|
|
|
3772 c.gray = display->background->green;
|
|
|
3773
|
|
|
3774 /* This is always an 8-bit sRGB value, using the 'green' channel
|
|
|
3775 * for gray is much better than calculating the luminance here;
|
|
|
3776 * we can get off-by-one errors in that calculation relative to
|
|
|
3777 * the app expectations and that will show up in transparent
|
|
|
3778 * pixels.
|
|
|
3779 */
|
|
|
3780 png_set_background_fixed(png_ptr, &c,
|
|
|
3781 PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
|
|
|
3782 0/*gamma: not used*/);
|
|
|
3783 }
|
|
|
3784
|
|
|
3785 else /* compose on row: implemented below. */
|
|
|
3786 {
|
|
|
3787 do_local_compose = 1;
|
|
|
3788 /* This leaves the alpha channel in the output, so it has to be
|
|
|
3789 * removed by the code below. Set the encoding to the 'OPTIMIZE'
|
|
|
3790 * one so the code only has to hack on the pixels that require
|
|
|
3791 * composition.
|
|
|
3792 */
|
|
|
3793 mode = PNG_ALPHA_OPTIMIZED;
|
|
|
3794 }
|
|
|
3795 }
|
|
|
3796
|
|
|
3797 else /* output needs an alpha channel */
|
|
|
3798 {
|
|
|
3799 /* This is tricky because it happens before the swap operation has
|
|
|
3800 * been accomplished; however, the swap does *not* swap the added
|
|
|
3801 * alpha channel (weird API), so it must be added in the correct
|
|
|
3802 * place.
|
|
|
3803 */
|
|
|
3804 png_uint_32 filler; /* opaque filler */
|
|
|
3805 int where;
|
|
|
3806
|
|
|
3807 if (linear)
|
|
|
3808 filler = 65535;
|
|
|
3809
|
|
|
3810 else
|
|
|
3811 filler = 255;
|
|
|
3812
|
|
|
3813 # ifdef PNG_FORMAT_AFIRST_SUPPORTED
|
|
|
3814 if (format & PNG_FORMAT_FLAG_AFIRST)
|
|
|
3815 {
|
|
|
3816 where = PNG_FILLER_BEFORE;
|
|
|
3817 change &= ~PNG_FORMAT_FLAG_AFIRST;
|
|
|
3818 }
|
|
|
3819
|
|
|
3820 else
|
|
|
3821 # endif
|
|
|
3822 where = PNG_FILLER_AFTER;
|
|
|
3823
|
|
|
3824 png_set_add_alpha(png_ptr, filler, where);
|
|
|
3825 }
|
|
|
3826
|
|
|
3827 /* This stops the (irrelevant) call to swap_alpha below. */
|
|
|
3828 change &= ~PNG_FORMAT_FLAG_ALPHA;
|
|
|
3829 }
|
|
|
3830
|
|
|
3831 /* Now set the alpha mode correctly; this is always done, even if there is
|
|
|
3832 * no alpha channel in either the input or the output because it correctly
|
|
|
3833 * sets the output gamma.
|
|
|
3834 */
|
|
|
3835 png_set_alpha_mode_fixed(png_ptr, mode, output_gamma);
|
|
|
3836
|
|
|
3837 # ifdef PNG_FORMAT_BGR_SUPPORTED
|
|
|
3838 if (change & PNG_FORMAT_FLAG_BGR)
|
|
|
3839 {
|
|
|
3840 /* Check only the output format; PNG is never BGR; don't do this if
|
|
|
3841 * the output is gray, but fix up the 'format' value in that case.
|
|
|
3842 */
|
|
|
3843 if (format & PNG_FORMAT_FLAG_COLOR)
|
|
|
3844 png_set_bgr(png_ptr);
|
|
|
3845
|
|
|
3846 else
|
|
|
3847 format &= ~PNG_FORMAT_FLAG_BGR;
|
|
|
3848
|
|
|
3849 change &= ~PNG_FORMAT_FLAG_BGR;
|
|
|
3850 }
|
|
|
3851 # endif
|
|
|
3852
|
|
|
3853 # ifdef PNG_FORMAT_AFIRST_SUPPORTED
|
|
|
3854 if (change & PNG_FORMAT_FLAG_AFIRST)
|
|
|
3855 {
|
|
|
3856 /* Only relevant if there is an alpha channel - it's particularly
|
|
|
3857 * important to handle this correctly because do_local_compose may
|
|
|
3858 * be set above and then libpng will keep the alpha channel for this
|
|
|
3859 * code to remove.
|
|
|
3860 */
|
|
|
3861 if (format & PNG_FORMAT_FLAG_ALPHA)
|
|
|
3862 {
|
|
|
3863 /* Disable this if doing a local background,
|
|
|
3864 * TODO: remove this when local background is no longer required.
|
|
|
3865 */
|
|
|
3866 if (do_local_background != 2)
|
|
|
3867 png_set_swap_alpha(png_ptr);
|
|
|
3868 }
|
|
|
3869
|
|
|
3870 else
|
|
|
3871 format &= ~PNG_FORMAT_FLAG_AFIRST;
|
|
|
3872
|
|
|
3873 change &= ~PNG_FORMAT_FLAG_AFIRST;
|
|
|
3874 }
|
|
|
3875 # endif
|
|
|
3876
|
|
|
3877 /* If the *output* is 16-bit then we need to check for a byte-swap on this
|
|
|
3878 * architecture.
|
|
|
3879 */
|
|
|
3880 if (linear)
|
|
|
3881 {
|
|
|
3882 PNG_CONST png_uint_16 le = 0x0001;
|
|
|
3883
|
|
|
3884 if (*(png_const_bytep)&le)
|
|
|
3885 png_set_swap(png_ptr);
|
|
|
3886 }
|
|
|
3887
|
|
|
3888 /* If change is not now 0 some transformation is missing - error out. */
|
|
|
3889 if (change)
|
|
|
3890 png_error(png_ptr, "png_read_image: unsupported transformation");
|
|
|
3891 }
|
|
|
3892
|
|
|
3893 PNG_SKIP_CHUNKS(png_ptr);
|
|
|
3894
|
|
|
3895 /* Update the 'info' structure and make sure the result is as required; first
|
|
|
3896 * make sure to turn on the interlace handling if it will be required
|
|
|
3897 * (because it can't be turned on *after* the call to png_read_update_info!)
|
|
|
3898 *
|
|
|
3899 * TODO: remove the do_local_background fixup below.
|
|
|
3900 */
|
|
|
3901 if (!do_local_compose && do_local_background != 2)
|
|
|
3902 passes = png_set_interlace_handling(png_ptr);
|
|
|
3903
|
|
|
3904 png_read_update_info(png_ptr, info_ptr);
|
|
|
3905
|
|
|
3906 {
|
|
|
3907 png_uint_32 info_format = 0;
|
|
|
3908
|
|
|
3909 if (info_ptr->color_type & PNG_COLOR_MASK_COLOR)
|
|
|
3910 info_format |= PNG_FORMAT_FLAG_COLOR;
|
|
|
3911
|
|
|
3912 if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
|
|
|
3913 {
|
|
|
3914 /* do_local_compose removes this channel below. */
|
|
|
3915 if (!do_local_compose)
|
|
|
3916 {
|
|
|
3917 /* do_local_background does the same if required. */
|
|
|
3918 if (do_local_background != 2 ||
|
|
|
3919 (format & PNG_FORMAT_FLAG_ALPHA) != 0)
|
|
|
3920 info_format |= PNG_FORMAT_FLAG_ALPHA;
|
|
|
3921 }
|
|
|
3922 }
|
|
|
3923
|
|
|
3924 else if (do_local_compose) /* internal error */
|
|
|
3925 png_error(png_ptr, "png_image_read: alpha channel lost");
|
|
|
3926
|
|
|
3927 if (info_ptr->bit_depth == 16)
|
|
|
3928 info_format |= PNG_FORMAT_FLAG_LINEAR;
|
|
|
3929
|
|
|
3930 # ifdef PNG_FORMAT_BGR_SUPPORTED
|
|
|
3931 if (png_ptr->transformations & PNG_BGR)
|
|
|
3932 info_format |= PNG_FORMAT_FLAG_BGR;
|
|
|
3933 # endif
|
|
|
3934
|
|
|
3935 # ifdef PNG_FORMAT_AFIRST_SUPPORTED
|
|
|
3936 if (do_local_background == 2)
|
|
|
3937 {
|
|
|
3938 if (format & PNG_FORMAT_FLAG_AFIRST)
|
|
|
3939 info_format |= PNG_FORMAT_FLAG_AFIRST;
|
|
|
3940 }
|
|
|
3941
|
|
|
3942 if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0 ||
|
|
|
3943 ((png_ptr->transformations & PNG_ADD_ALPHA) != 0 &&
|
|
|
3944 (png_ptr->flags & PNG_FLAG_FILLER_AFTER) == 0))
|
|
|
3945 {
|
|
|
3946 if (do_local_background == 2)
|
|
|
3947 png_error(png_ptr, "unexpected alpha swap transformation");
|
|
|
3948
|
|
|
3949 info_format |= PNG_FORMAT_FLAG_AFIRST;
|
|
|
3950 }
|
|
|
3951 # endif
|
|
|
3952
|
|
|
3953 /* This is actually an internal error. */
|
|
|
3954 if (info_format != format)
|
|
|
3955 png_error(png_ptr, "png_read_image: invalid transformations");
|
|
|
3956 }
|
|
|
3957
|
|
|
3958 /* Now read the rows. If do_local_compose is set then it is necessary to use
|
|
|
3959 * a local row buffer. The output will be GA, RGBA or BGRA and must be
|
|
|
3960 * converted to G, RGB or BGR as appropriate. The 'local_row' member of the
|
|
|
3961 * display acts as a flag.
|
|
|
3962 */
|
|
|
3963 {
|
|
|
3964 png_voidp first_row = display->buffer;
|
|
|
3965 ptrdiff_t row_bytes = display->row_stride;
|
|
|
3966
|
|
|
3967 if (linear)
|
|
|
3968 row_bytes *= 2;
|
|
|
3969
|
|
|
3970 /* The following expression is designed to work correctly whether it gives
|
|
|
3971 * a signed or an unsigned result.
|
|
|
3972 */
|
|
|
3973 if (row_bytes < 0)
|
|
|
3974 {
|
|
|
3975 char *ptr = png_voidcast(char*, first_row);
|
|
|
3976 ptr += (image->height-1) * (-row_bytes);
|
|
|
3977 first_row = png_voidcast(png_voidp, ptr);
|
|
|
3978 }
|
|
|
3979
|
|
|
3980 display->first_row = first_row;
|
|
|
3981 display->row_bytes = row_bytes;
|
|
|
3982 }
|
|
|
3983
|
|
|
3984 if (do_local_compose)
|
|
|
3985 {
|
|
|
3986 int result;
|
|
|
3987 png_voidp row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr));
|
|
|
3988
|
|
|
3989 display->local_row = row;
|
|
|
3990 result = png_safe_execute(image, png_image_read_composite, display);
|
|
|
3991 display->local_row = NULL;
|
|
|
3992 png_free(png_ptr, row);
|
|
|
3993
|
|
|
3994 return result;
|
|
|
3995 }
|
|
|
3996
|
|
|
3997 else if (do_local_background == 2)
|
|
|
3998 {
|
|
|
3999 int result;
|
|
|
4000 png_voidp row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr));
|
|
|
4001
|
|
|
4002 display->local_row = row;
|
|
|
4003 result = png_safe_execute(image, png_image_read_background, display);
|
|
|
4004 display->local_row = NULL;
|
|
|
4005 png_free(png_ptr, row);
|
|
|
4006
|
|
|
4007 return result;
|
|
|
4008 }
|
|
|
4009
|
|
|
4010 else
|
|
|
4011 {
|
|
|
4012 png_alloc_size_t row_bytes = display->row_bytes;
|
|
|
4013
|
|
|
4014 while (--passes >= 0)
|
|
|
4015 {
|
|
|
4016 png_uint_32 y = image->height;
|
|
|
4017 png_bytep row = png_voidcast(png_bytep, display->first_row);
|
|
|
4018
|
|
|
4019 while (y-- > 0)
|
|
|
4020 {
|
|
|
4021 png_read_row(png_ptr, row, NULL);
|
|
|
4022 row += row_bytes;
|
|
|
4023 }
|
|
|
4024 }
|
|
|
4025
|
|
|
4026 return 1;
|
|
|
4027 }
|
|
|
4028 }
|
|
|
4029
|
|
|
4030 int PNGAPI
|
|
|
4031 png_image_finish_read(png_imagep image, png_const_colorp background,
|
|
|
4032 void *buffer, png_int_32 row_stride, void *colormap)
|
|
|
4033 {
|
|
|
4034 if (image != NULL && image->version == PNG_IMAGE_VERSION)
|
|
|
4035 {
|
|
|
4036 png_uint_32 check;
|
|
|
4037
|
|
|
4038 if (row_stride == 0)
|
|
|
4039 row_stride = PNG_IMAGE_ROW_STRIDE(*image);
|
|
|
4040
|
|
|
4041 if (row_stride < 0)
|
|
|
4042 check = -row_stride;
|
|
|
4043
|
|
|
4044 else
|
|
|
4045 check = row_stride;
|
|
|
4046
|
|
|
4047 if (image->opaque != NULL && buffer != NULL &&
|
|
|
4048 check >= PNG_IMAGE_ROW_STRIDE(*image))
|
|
|
4049 {
|
|
|
4050 if ((image->format & PNG_FORMAT_FLAG_COLORMAP) == 0 ||
|
|
|
4051 (image->colormap_entries > 0 && colormap != NULL))
|
|
|
4052 {
|
|
|
4053 int result;
|
|
|
4054 png_image_read_control display;
|
|
|
4055
|
|
|
4056 memset(&display, 0, (sizeof display));
|
|
|
4057 display.image = image;
|
|
|
4058 display.buffer = buffer;
|
|
|
4059 display.row_stride = row_stride;
|
|
|
4060 display.colormap = colormap;
|
|
|
4061 display.background = background;
|
|
|
4062 display.local_row = NULL;
|
|
|
4063
|
|
|
4064 /* Choose the correct 'end' routine; for the color-map case all the
|
|
|
4065 * setup has already been done.
|
|
|
4066 */
|
|
|
4067 if (image->format & PNG_FORMAT_FLAG_COLORMAP)
|
|
|
4068 result =
|
|
|
4069 png_safe_execute(image, png_image_read_colormap, &display) &&
|
|
|
4070 png_safe_execute(image, png_image_read_colormapped, &display);
|
|
|
4071
|
|
|
4072 else
|
|
|
4073 result =
|
|
|
4074 png_safe_execute(image, png_image_read_direct, &display);
|
|
|
4075
|
|
|
4076 png_image_free(image);
|
|
|
4077 return result;
|
|
|
4078 }
|
|
|
4079
|
|
|
4080 else
|
|
|
4081 return png_image_error(image,
|
|
|
4082 "png_image_finish_read[color-map]: no color-map");
|
|
|
4083 }
|
|
|
4084
|
|
|
4085 else
|
|
|
4086 return png_image_error(image,
|
|
|
4087 "png_image_finish_read: invalid argument");
|
|
|
4088 }
|
|
|
4089
|
|
|
4090 else if (image != NULL)
|
|
|
4091 return png_image_error(image,
|
|
|
4092 "png_image_finish_read: damaged PNG_IMAGE_VERSION");
|
|
|
4093
|
|
|
4094 return 0;
|
|
|
4095 }
|
|
|
4096
|
|
|
4097 #endif /* PNG_SIMPLIFIED_READ_SUPPORTED */
|
|
|
4098 #endif /* PNG_READ_SUPPORTED */
|
