2 /* pngrtran.c - transforms the data in a row for PNG readers
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4 * Copyright (c) 2018-2019 Cosmin Truta
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5 * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
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6 * Copyright (c) 1996-1997 Andreas Dilger
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7 * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
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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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13 * This file contains functions optionally called by an application
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14 * in order to tell libpng how to handle data when reading a PNG.
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15 * Transformations that are used in both reading and writing are
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19 #include "pngpriv.h"
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21 #ifdef PNG_ARM_NEON_IMPLEMENTATION
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22 # if PNG_ARM_NEON_IMPLEMENTATION == 1
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23 # define PNG_ARM_NEON_INTRINSICS_AVAILABLE
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24 # if defined(_MSC_VER) && defined(_M_ARM64)
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25 # include <arm64_neon.h>
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27 # include <arm_neon.h>
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32 #ifdef PNG_READ_SUPPORTED
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34 /* Set the action on getting a CRC error for an ancillary or critical chunk. */
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36 png_set_crc_action(png_structrp png_ptr, int crit_action, int ancil_action)
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38 png_debug(1, "in png_set_crc_action");
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40 if (png_ptr == NULL)
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43 /* Tell libpng how we react to CRC errors in critical chunks */
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44 switch (crit_action)
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46 case PNG_CRC_NO_CHANGE: /* Leave setting as is */
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49 case PNG_CRC_WARN_USE: /* Warn/use data */
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50 png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
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51 png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE;
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54 case PNG_CRC_QUIET_USE: /* Quiet/use data */
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55 png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
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56 png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE |
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57 PNG_FLAG_CRC_CRITICAL_IGNORE;
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60 case PNG_CRC_WARN_DISCARD: /* Not a valid action for critical data */
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61 png_warning(png_ptr,
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62 "Can't discard critical data on CRC error");
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64 case PNG_CRC_ERROR_QUIT: /* Error/quit */
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66 case PNG_CRC_DEFAULT:
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68 png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
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72 /* Tell libpng how we react to CRC errors in ancillary chunks */
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73 switch (ancil_action)
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75 case PNG_CRC_NO_CHANGE: /* Leave setting as is */
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78 case PNG_CRC_WARN_USE: /* Warn/use data */
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79 png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
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80 png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE;
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83 case PNG_CRC_QUIET_USE: /* Quiet/use data */
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84 png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
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85 png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE |
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86 PNG_FLAG_CRC_ANCILLARY_NOWARN;
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89 case PNG_CRC_ERROR_QUIT: /* Error/quit */
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90 png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
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91 png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_NOWARN;
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94 case PNG_CRC_WARN_DISCARD: /* Warn/discard data */
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96 case PNG_CRC_DEFAULT:
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98 png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
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103 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
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104 /* Is it OK to set a transformation now? Only if png_start_read_image or
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105 * png_read_update_info have not been called. It is not necessary for the IHDR
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106 * to have been read in all cases; the need_IHDR parameter allows for this
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110 png_rtran_ok(png_structrp png_ptr, int need_IHDR)
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112 if (png_ptr != NULL)
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114 if ((png_ptr->flags & PNG_FLAG_ROW_INIT) != 0)
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115 png_app_error(png_ptr,
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116 "invalid after png_start_read_image or png_read_update_info");
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118 else if (need_IHDR && (png_ptr->mode & PNG_HAVE_IHDR) == 0)
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119 png_app_error(png_ptr, "invalid before the PNG header has been read");
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123 /* Turn on failure to initialize correctly for all transforms. */
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124 png_ptr->flags |= PNG_FLAG_DETECT_UNINITIALIZED;
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130 return 0; /* no png_error possible! */
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134 #ifdef PNG_READ_BACKGROUND_SUPPORTED
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135 /* Handle alpha and tRNS via a background color */
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137 png_set_background_fixed(png_structrp png_ptr,
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138 png_const_color_16p background_color, int background_gamma_code,
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139 int need_expand, png_fixed_point background_gamma)
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141 png_debug(1, "in png_set_background_fixed");
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143 if (png_rtran_ok(png_ptr, 0) == 0 || background_color == NULL)
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146 if (background_gamma_code == PNG_BACKGROUND_GAMMA_UNKNOWN)
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148 png_warning(png_ptr, "Application must supply a known background gamma");
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152 png_ptr->transformations |= PNG_COMPOSE | PNG_STRIP_ALPHA;
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153 png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
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154 png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
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156 png_ptr->background = *background_color;
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157 png_ptr->background_gamma = background_gamma;
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158 png_ptr->background_gamma_type = (png_byte)(background_gamma_code);
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159 if (need_expand != 0)
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160 png_ptr->transformations |= PNG_BACKGROUND_EXPAND;
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162 png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND;
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165 # ifdef PNG_FLOATING_POINT_SUPPORTED
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167 png_set_background(png_structrp png_ptr,
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168 png_const_color_16p background_color, int background_gamma_code,
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169 int need_expand, double background_gamma)
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171 png_set_background_fixed(png_ptr, background_color, background_gamma_code,
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172 need_expand, png_fixed(png_ptr, background_gamma, "png_set_background"));
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174 # endif /* FLOATING_POINT */
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175 #endif /* READ_BACKGROUND */
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177 /* Scale 16-bit depth files to 8-bit depth. If both of these are set then the
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178 * one that pngrtran does first (scale) happens. This is necessary to allow the
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179 * TRANSFORM and API behavior to be somewhat consistent, and it's simpler.
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181 #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
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183 png_set_scale_16(png_structrp png_ptr)
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185 png_debug(1, "in png_set_scale_16");
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187 if (png_rtran_ok(png_ptr, 0) == 0)
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190 png_ptr->transformations |= PNG_SCALE_16_TO_8;
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194 #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
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195 /* Chop 16-bit depth files to 8-bit depth */
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197 png_set_strip_16(png_structrp png_ptr)
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199 png_debug(1, "in png_set_strip_16");
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201 if (png_rtran_ok(png_ptr, 0) == 0)
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204 png_ptr->transformations |= PNG_16_TO_8;
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208 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
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210 png_set_strip_alpha(png_structrp png_ptr)
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212 png_debug(1, "in png_set_strip_alpha");
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214 if (png_rtran_ok(png_ptr, 0) == 0)
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217 png_ptr->transformations |= PNG_STRIP_ALPHA;
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221 #if defined(PNG_READ_ALPHA_MODE_SUPPORTED) || defined(PNG_READ_GAMMA_SUPPORTED)
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222 static png_fixed_point
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223 translate_gamma_flags(png_structrp png_ptr, png_fixed_point output_gamma,
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226 /* Check for flag values. The main reason for having the old Mac value as a
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227 * flag is that it is pretty near impossible to work out what the correct
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228 * value is from Apple documentation - a working Mac system is needed to
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229 * discover the value!
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231 if (output_gamma == PNG_DEFAULT_sRGB ||
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232 output_gamma == PNG_FP_1 / PNG_DEFAULT_sRGB)
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234 /* If there is no sRGB support this just sets the gamma to the standard
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235 * sRGB value. (This is a side effect of using this function!)
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237 # ifdef PNG_READ_sRGB_SUPPORTED
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238 png_ptr->flags |= PNG_FLAG_ASSUME_sRGB;
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240 PNG_UNUSED(png_ptr)
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242 if (is_screen != 0)
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243 output_gamma = PNG_GAMMA_sRGB;
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245 output_gamma = PNG_GAMMA_sRGB_INVERSE;
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248 else if (output_gamma == PNG_GAMMA_MAC_18 ||
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249 output_gamma == PNG_FP_1 / PNG_GAMMA_MAC_18)
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251 if (is_screen != 0)
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252 output_gamma = PNG_GAMMA_MAC_OLD;
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254 output_gamma = PNG_GAMMA_MAC_INVERSE;
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257 return output_gamma;
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260 # ifdef PNG_FLOATING_POINT_SUPPORTED
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261 static png_fixed_point
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262 convert_gamma_value(png_structrp png_ptr, double output_gamma)
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264 /* The following silently ignores cases where fixed point (times 100,000)
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265 * gamma values are passed to the floating point API. This is safe and it
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266 * means the fixed point constants work just fine with the floating point
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267 * API. The alternative would just lead to undetected errors and spurious
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268 * bug reports. Negative values fail inside the _fixed API unless they
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269 * correspond to the flag values.
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271 if (output_gamma > 0 && output_gamma < 128)
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272 output_gamma *= PNG_FP_1;
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274 /* This preserves -1 and -2 exactly: */
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275 output_gamma = floor(output_gamma + .5);
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277 if (output_gamma > PNG_FP_MAX || output_gamma < PNG_FP_MIN)
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278 png_fixed_error(png_ptr, "gamma value");
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280 return (png_fixed_point)output_gamma;
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283 #endif /* READ_ALPHA_MODE || READ_GAMMA */
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285 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
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287 png_set_alpha_mode_fixed(png_structrp png_ptr, int mode,
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288 png_fixed_point output_gamma)
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291 png_fixed_point file_gamma;
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293 png_debug(1, "in png_set_alpha_mode");
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295 if (png_rtran_ok(png_ptr, 0) == 0)
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298 output_gamma = translate_gamma_flags(png_ptr, output_gamma, 1/*screen*/);
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300 /* Validate the value to ensure it is in a reasonable range. The value
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301 * is expected to be 1 or greater, but this range test allows for some
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302 * viewing correction values. The intent is to weed out users of this API
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303 * who use the inverse of the gamma value accidentally! Since some of these
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304 * values are reasonable this may have to be changed:
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306 * 1.6.x: changed from 0.07..3 to 0.01..100 (to accommodate the optimal 16-bit
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307 * gamma of 36, and its reciprocal.)
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309 if (output_gamma < 1000 || output_gamma > 10000000)
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310 png_error(png_ptr, "output gamma out of expected range");
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312 /* The default file gamma is the inverse of the output gamma; the output
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313 * gamma may be changed below so get the file value first:
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315 file_gamma = png_reciprocal(output_gamma);
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317 /* There are really 8 possibilities here, composed of any combination
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320 * premultiply the color channels
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321 * do not encode non-opaque pixels
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322 * encode the alpha as well as the color channels
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324 * The differences disappear if the input/output ('screen') gamma is 1.0,
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325 * because then the encoding is a no-op and there is only the choice of
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326 * premultiplying the color channels or not.
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328 * png_set_alpha_mode and png_set_background interact because both use
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329 * png_compose to do the work. Calling both is only useful when
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330 * png_set_alpha_mode is used to set the default mode - PNG_ALPHA_PNG - along
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331 * with a default gamma value. Otherwise PNG_COMPOSE must not be set.
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335 case PNG_ALPHA_PNG: /* default: png standard */
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336 /* No compose, but it may be set by png_set_background! */
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337 png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
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338 png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
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341 case PNG_ALPHA_ASSOCIATED: /* color channels premultiplied */
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343 png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
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344 png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
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345 /* The output is linear: */
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346 output_gamma = PNG_FP_1;
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349 case PNG_ALPHA_OPTIMIZED: /* associated, non-opaque pixels linear */
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351 png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
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352 png_ptr->flags |= PNG_FLAG_OPTIMIZE_ALPHA;
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353 /* output_gamma records the encoding of opaque pixels! */
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356 case PNG_ALPHA_BROKEN: /* associated, non-linear, alpha encoded */
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358 png_ptr->transformations |= PNG_ENCODE_ALPHA;
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359 png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
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363 png_error(png_ptr, "invalid alpha mode");
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366 /* Only set the default gamma if the file gamma has not been set (this has
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367 * the side effect that the gamma in a second call to png_set_alpha_mode will
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370 if (png_ptr->colorspace.gamma == 0)
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372 png_ptr->colorspace.gamma = file_gamma;
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373 png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
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376 /* But always set the output gamma: */
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377 png_ptr->screen_gamma = output_gamma;
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379 /* Finally, if pre-multiplying, set the background fields to achieve the
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384 /* And obtain alpha pre-multiplication by composing on black: */
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385 memset(&png_ptr->background, 0, (sizeof png_ptr->background));
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386 png_ptr->background_gamma = png_ptr->colorspace.gamma; /* just in case */
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387 png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_FILE;
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388 png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND;
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390 if ((png_ptr->transformations & PNG_COMPOSE) != 0)
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392 "conflicting calls to set alpha mode and background");
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394 png_ptr->transformations |= PNG_COMPOSE;
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398 # ifdef PNG_FLOATING_POINT_SUPPORTED
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400 png_set_alpha_mode(png_structrp png_ptr, int mode, double output_gamma)
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402 png_set_alpha_mode_fixed(png_ptr, mode, convert_gamma_value(png_ptr,
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408 #ifdef PNG_READ_QUANTIZE_SUPPORTED
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409 /* Dither file to 8-bit. Supply a palette, the current number
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410 * of elements in the palette, the maximum number of elements
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411 * allowed, and a histogram if possible. If the current number
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412 * of colors is greater than the maximum number, the palette will be
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413 * modified to fit in the maximum number. "full_quantize" indicates
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414 * whether we need a quantizing cube set up for RGB images, or if we
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415 * simply are reducing the number of colors in a paletted image.
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418 typedef struct png_dsort_struct
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420 struct png_dsort_struct * next;
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424 typedef png_dsort * png_dsortp;
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425 typedef png_dsort * * png_dsortpp;
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428 png_set_quantize(png_structrp png_ptr, png_colorp palette,
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429 int num_palette, int maximum_colors, png_const_uint_16p histogram,
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432 png_debug(1, "in png_set_quantize");
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434 if (png_rtran_ok(png_ptr, 0) == 0)
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437 png_ptr->transformations |= PNG_QUANTIZE;
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439 if (full_quantize == 0)
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443 png_ptr->quantize_index = (png_bytep)png_malloc(png_ptr,
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444 (png_alloc_size_t)((png_uint_32)num_palette * (sizeof (png_byte))));
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445 for (i = 0; i < num_palette; i++)
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446 png_ptr->quantize_index[i] = (png_byte)i;
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449 if (num_palette > maximum_colors)
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451 if (histogram != NULL)
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453 /* This is easy enough, just throw out the least used colors.
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454 * Perhaps not the best solution, but good enough.
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459 /* Initialize an array to sort colors */
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460 png_ptr->quantize_sort = (png_bytep)png_malloc(png_ptr,
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461 (png_alloc_size_t)((png_uint_32)num_palette * (sizeof (png_byte))));
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463 /* Initialize the quantize_sort array */
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464 for (i = 0; i < num_palette; i++)
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465 png_ptr->quantize_sort[i] = (png_byte)i;
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467 /* Find the least used palette entries by starting a
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468 * bubble sort, and running it until we have sorted
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469 * out enough colors. Note that we don't care about
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470 * sorting all the colors, just finding which are
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474 for (i = num_palette - 1; i >= maximum_colors; i--)
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476 int done; /* To stop early if the list is pre-sorted */
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480 for (j = 0; j < i; j++)
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482 if (histogram[png_ptr->quantize_sort[j]]
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483 < histogram[png_ptr->quantize_sort[j + 1]])
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487 t = png_ptr->quantize_sort[j];
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488 png_ptr->quantize_sort[j] = png_ptr->quantize_sort[j + 1];
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489 png_ptr->quantize_sort[j + 1] = t;
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498 /* Swap the palette around, and set up a table, if necessary */
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499 if (full_quantize != 0)
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501 int j = num_palette;
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503 /* Put all the useful colors within the max, but don't
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506 for (i = 0; i < maximum_colors; i++)
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508 if ((int)png_ptr->quantize_sort[i] >= maximum_colors)
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512 while ((int)png_ptr->quantize_sort[j] >= maximum_colors);
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514 palette[i] = palette[j];
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520 int j = num_palette;
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522 /* Move all the used colors inside the max limit, and
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523 * develop a translation table.
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525 for (i = 0; i < maximum_colors; i++)
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527 /* Only move the colors we need to */
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528 if ((int)png_ptr->quantize_sort[i] >= maximum_colors)
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530 png_color tmp_color;
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534 while ((int)png_ptr->quantize_sort[j] >= maximum_colors);
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536 tmp_color = palette[j];
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537 palette[j] = palette[i];
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538 palette[i] = tmp_color;
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539 /* Indicate where the color went */
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540 png_ptr->quantize_index[j] = (png_byte)i;
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541 png_ptr->quantize_index[i] = (png_byte)j;
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545 /* Find closest color for those colors we are not using */
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546 for (i = 0; i < num_palette; i++)
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548 if ((int)png_ptr->quantize_index[i] >= maximum_colors)
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550 int min_d, k, min_k, d_index;
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552 /* Find the closest color to one we threw out */
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553 d_index = png_ptr->quantize_index[i];
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554 min_d = PNG_COLOR_DIST(palette[d_index], palette[0]);
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555 for (k = 1, min_k = 0; k < maximum_colors; k++)
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559 d = PNG_COLOR_DIST(palette[d_index], palette[k]);
\r
567 /* Point to closest color */
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568 png_ptr->quantize_index[i] = (png_byte)min_k;
\r
572 png_free(png_ptr, png_ptr->quantize_sort);
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573 png_ptr->quantize_sort = NULL;
\r
577 /* This is much harder to do simply (and quickly). Perhaps
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578 * we need to go through a median cut routine, but those
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579 * don't always behave themselves with only a few colors
\r
580 * as input. So we will just find the closest two colors,
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581 * and throw out one of them (chosen somewhat randomly).
\r
582 * [We don't understand this at all, so if someone wants to
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583 * work on improving it, be our guest - AED, GRP]
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587 int num_new_palette;
\r
593 /* Initialize palette index arrays */
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594 png_ptr->index_to_palette = (png_bytep)png_malloc(png_ptr,
\r
595 (png_alloc_size_t)((png_uint_32)num_palette *
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596 (sizeof (png_byte))));
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597 png_ptr->palette_to_index = (png_bytep)png_malloc(png_ptr,
\r
598 (png_alloc_size_t)((png_uint_32)num_palette *
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599 (sizeof (png_byte))));
\r
601 /* Initialize the sort array */
\r
602 for (i = 0; i < num_palette; i++)
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604 png_ptr->index_to_palette[i] = (png_byte)i;
\r
605 png_ptr->palette_to_index[i] = (png_byte)i;
\r
608 hash = (png_dsortpp)png_calloc(png_ptr, (png_alloc_size_t)(769 *
\r
609 (sizeof (png_dsortp))));
\r
611 num_new_palette = num_palette;
\r
613 /* Initial wild guess at how far apart the farthest pixel
\r
614 * pair we will be eliminating will be. Larger
\r
615 * numbers mean more areas will be allocated, Smaller
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616 * numbers run the risk of not saving enough data, and
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617 * having to do this all over again.
\r
619 * I have not done extensive checking on this number.
\r
623 while (num_new_palette > maximum_colors)
\r
625 for (i = 0; i < num_new_palette - 1; i++)
\r
629 for (j = i + 1; j < num_new_palette; j++)
\r
633 d = PNG_COLOR_DIST(palette[i], palette[j]);
\r
638 t = (png_dsortp)png_malloc_warn(png_ptr,
\r
639 (png_alloc_size_t)(sizeof (png_dsort)));
\r
645 t->left = (png_byte)i;
\r
646 t->right = (png_byte)j;
\r
655 for (i = 0; i <= max_d; i++)
\r
657 if (hash[i] != NULL)
\r
661 for (p = hash[i]; p; p = p->next)
\r
663 if ((int)png_ptr->index_to_palette[p->left]
\r
664 < num_new_palette &&
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665 (int)png_ptr->index_to_palette[p->right]
\r
670 if (num_new_palette & 0x01)
\r
682 palette[png_ptr->index_to_palette[j]]
\r
683 = palette[num_new_palette];
\r
684 if (full_quantize == 0)
\r
688 for (k = 0; k < num_palette; k++)
\r
690 if (png_ptr->quantize_index[k] ==
\r
691 png_ptr->index_to_palette[j])
\r
692 png_ptr->quantize_index[k] =
\r
693 png_ptr->index_to_palette[next_j];
\r
695 if ((int)png_ptr->quantize_index[k] ==
\r
697 png_ptr->quantize_index[k] =
\r
698 png_ptr->index_to_palette[j];
\r
702 png_ptr->index_to_palette[png_ptr->palette_to_index
\r
703 [num_new_palette]] = png_ptr->index_to_palette[j];
\r
705 png_ptr->palette_to_index[png_ptr->index_to_palette[j]]
\r
706 = png_ptr->palette_to_index[num_new_palette];
\r
708 png_ptr->index_to_palette[j] =
\r
709 (png_byte)num_new_palette;
\r
711 png_ptr->palette_to_index[num_new_palette] =
\r
714 if (num_new_palette <= maximum_colors)
\r
717 if (num_new_palette <= maximum_colors)
\r
722 for (i = 0; i < 769; i++)
\r
724 if (hash[i] != NULL)
\r
726 png_dsortp p = hash[i];
\r
730 png_free(png_ptr, p);
\r
738 png_free(png_ptr, hash);
\r
739 png_free(png_ptr, png_ptr->palette_to_index);
\r
740 png_free(png_ptr, png_ptr->index_to_palette);
\r
741 png_ptr->palette_to_index = NULL;
\r
742 png_ptr->index_to_palette = NULL;
\r
744 num_palette = maximum_colors;
\r
746 if (png_ptr->palette == NULL)
\r
748 png_ptr->palette = palette;
\r
750 png_ptr->num_palette = (png_uint_16)num_palette;
\r
752 if (full_quantize != 0)
\r
755 png_bytep distance;
\r
756 int total_bits = PNG_QUANTIZE_RED_BITS + PNG_QUANTIZE_GREEN_BITS +
\r
757 PNG_QUANTIZE_BLUE_BITS;
\r
758 int num_red = (1 << PNG_QUANTIZE_RED_BITS);
\r
759 int num_green = (1 << PNG_QUANTIZE_GREEN_BITS);
\r
760 int num_blue = (1 << PNG_QUANTIZE_BLUE_BITS);
\r
761 size_t num_entries = ((size_t)1 << total_bits);
\r
763 png_ptr->palette_lookup = (png_bytep)png_calloc(png_ptr,
\r
764 (png_alloc_size_t)(num_entries * (sizeof (png_byte))));
\r
766 distance = (png_bytep)png_malloc(png_ptr, (png_alloc_size_t)(num_entries *
\r
767 (sizeof (png_byte))));
\r
769 memset(distance, 0xff, num_entries * (sizeof (png_byte)));
\r
771 for (i = 0; i < num_palette; i++)
\r
774 int r = (palette[i].red >> (8 - PNG_QUANTIZE_RED_BITS));
\r
775 int g = (palette[i].green >> (8 - PNG_QUANTIZE_GREEN_BITS));
\r
776 int b = (palette[i].blue >> (8 - PNG_QUANTIZE_BLUE_BITS));
\r
778 for (ir = 0; ir < num_red; ir++)
\r
780 /* int dr = abs(ir - r); */
\r
781 int dr = ((ir > r) ? ir - r : r - ir);
\r
782 int index_r = (ir << (PNG_QUANTIZE_BLUE_BITS +
\r
783 PNG_QUANTIZE_GREEN_BITS));
\r
785 for (ig = 0; ig < num_green; ig++)
\r
787 /* int dg = abs(ig - g); */
\r
788 int dg = ((ig > g) ? ig - g : g - ig);
\r
790 int dm = ((dr > dg) ? dr : dg);
\r
791 int index_g = index_r | (ig << PNG_QUANTIZE_BLUE_BITS);
\r
793 for (ib = 0; ib < num_blue; ib++)
\r
795 int d_index = index_g | ib;
\r
796 /* int db = abs(ib - b); */
\r
797 int db = ((ib > b) ? ib - b : b - ib);
\r
798 int dmax = ((dm > db) ? dm : db);
\r
799 int d = dmax + dt + db;
\r
801 if (d < (int)distance[d_index])
\r
803 distance[d_index] = (png_byte)d;
\r
804 png_ptr->palette_lookup[d_index] = (png_byte)i;
\r
811 png_free(png_ptr, distance);
\r
814 #endif /* READ_QUANTIZE */
\r
816 #ifdef PNG_READ_GAMMA_SUPPORTED
\r
818 png_set_gamma_fixed(png_structrp png_ptr, png_fixed_point scrn_gamma,
\r
819 png_fixed_point file_gamma)
\r
821 png_debug(1, "in png_set_gamma_fixed");
\r
823 if (png_rtran_ok(png_ptr, 0) == 0)
\r
826 /* New in libpng-1.5.4 - reserve particular negative values as flags. */
\r
827 scrn_gamma = translate_gamma_flags(png_ptr, scrn_gamma, 1/*screen*/);
\r
828 file_gamma = translate_gamma_flags(png_ptr, file_gamma, 0/*file*/);
\r
830 /* Checking the gamma values for being >0 was added in 1.5.4 along with the
\r
831 * premultiplied alpha support; this actually hides an undocumented feature
\r
832 * of the previous implementation which allowed gamma processing to be
\r
833 * disabled in background handling. There is no evidence (so far) that this
\r
834 * was being used; however, png_set_background itself accepted and must still
\r
835 * accept '0' for the gamma value it takes, because it isn't always used.
\r
837 * Since this is an API change (albeit a very minor one that removes an
\r
838 * undocumented API feature) the following checks were only enabled in
\r
841 if (file_gamma <= 0)
\r
842 png_error(png_ptr, "invalid file gamma in png_set_gamma");
\r
844 if (scrn_gamma <= 0)
\r
845 png_error(png_ptr, "invalid screen gamma in png_set_gamma");
\r
847 /* Set the gamma values unconditionally - this overrides the value in the PNG
\r
848 * file if a gAMA chunk was present. png_set_alpha_mode provides a
\r
849 * different, easier, way to default the file gamma.
\r
851 png_ptr->colorspace.gamma = file_gamma;
\r
852 png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
\r
853 png_ptr->screen_gamma = scrn_gamma;
\r
856 # ifdef PNG_FLOATING_POINT_SUPPORTED
\r
858 png_set_gamma(png_structrp png_ptr, double scrn_gamma, double file_gamma)
\r
860 png_set_gamma_fixed(png_ptr, convert_gamma_value(png_ptr, scrn_gamma),
\r
861 convert_gamma_value(png_ptr, file_gamma));
\r
863 # endif /* FLOATING_POINT */
\r
864 #endif /* READ_GAMMA */
\r
866 #ifdef PNG_READ_EXPAND_SUPPORTED
\r
867 /* Expand paletted images to RGB, expand grayscale images of
\r
868 * less than 8-bit depth to 8-bit depth, and expand tRNS chunks
\r
869 * to alpha channels.
\r
872 png_set_expand(png_structrp png_ptr)
\r
874 png_debug(1, "in png_set_expand");
\r
876 if (png_rtran_ok(png_ptr, 0) == 0)
\r
879 png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
\r
882 /* GRR 19990627: the following three functions currently are identical
\r
883 * to png_set_expand(). However, it is entirely reasonable that someone
\r
884 * might wish to expand an indexed image to RGB but *not* expand a single,
\r
885 * fully transparent palette entry to a full alpha channel--perhaps instead
\r
886 * convert tRNS to the grayscale/RGB format (16-bit RGB value), or replace
\r
887 * the transparent color with a particular RGB value, or drop tRNS entirely.
\r
888 * IOW, a future version of the library may make the transformations flag
\r
889 * a bit more fine-grained, with separate bits for each of these three
\r
892 * More to the point, these functions make it obvious what libpng will be
\r
893 * doing, whereas "expand" can (and does) mean any number of things.
\r
895 * GRP 20060307: In libpng-1.2.9, png_set_gray_1_2_4_to_8() was modified
\r
896 * to expand only the sample depth but not to expand the tRNS to alpha
\r
897 * and its name was changed to png_set_expand_gray_1_2_4_to_8().
\r
900 /* Expand paletted images to RGB. */
\r
902 png_set_palette_to_rgb(png_structrp png_ptr)
\r
904 png_debug(1, "in png_set_palette_to_rgb");
\r
906 if (png_rtran_ok(png_ptr, 0) == 0)
\r
909 png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
\r
912 /* Expand grayscale images of less than 8-bit depth to 8 bits. */
\r
914 png_set_expand_gray_1_2_4_to_8(png_structrp png_ptr)
\r
916 png_debug(1, "in png_set_expand_gray_1_2_4_to_8");
\r
918 if (png_rtran_ok(png_ptr, 0) == 0)
\r
921 png_ptr->transformations |= PNG_EXPAND;
\r
924 /* Expand tRNS chunks to alpha channels. */
\r
926 png_set_tRNS_to_alpha(png_structrp png_ptr)
\r
928 png_debug(1, "in png_set_tRNS_to_alpha");
\r
930 if (png_rtran_ok(png_ptr, 0) == 0)
\r
933 png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
\r
935 #endif /* READ_EXPAND */
\r
937 #ifdef PNG_READ_EXPAND_16_SUPPORTED
\r
938 /* Expand to 16-bit channels, expand the tRNS chunk too (because otherwise
\r
939 * it may not work correctly.)
\r
942 png_set_expand_16(png_structrp png_ptr)
\r
944 png_debug(1, "in png_set_expand_16");
\r
946 if (png_rtran_ok(png_ptr, 0) == 0)
\r
949 png_ptr->transformations |= (PNG_EXPAND_16 | PNG_EXPAND | PNG_EXPAND_tRNS);
\r
953 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
\r
955 png_set_gray_to_rgb(png_structrp png_ptr)
\r
957 png_debug(1, "in png_set_gray_to_rgb");
\r
959 if (png_rtran_ok(png_ptr, 0) == 0)
\r
962 /* Because rgb must be 8 bits or more: */
\r
963 png_set_expand_gray_1_2_4_to_8(png_ptr);
\r
964 png_ptr->transformations |= PNG_GRAY_TO_RGB;
\r
968 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
\r
970 png_set_rgb_to_gray_fixed(png_structrp png_ptr, int error_action,
\r
971 png_fixed_point red, png_fixed_point green)
\r
973 png_debug(1, "in png_set_rgb_to_gray");
\r
975 /* Need the IHDR here because of the check on color_type below. */
\r
976 /* TODO: fix this */
\r
977 if (png_rtran_ok(png_ptr, 1) == 0)
\r
980 switch (error_action)
\r
982 case PNG_ERROR_ACTION_NONE:
\r
983 png_ptr->transformations |= PNG_RGB_TO_GRAY;
\r
986 case PNG_ERROR_ACTION_WARN:
\r
987 png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN;
\r
990 case PNG_ERROR_ACTION_ERROR:
\r
991 png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR;
\r
995 png_error(png_ptr, "invalid error action to rgb_to_gray");
\r
998 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
\r
999 #ifdef PNG_READ_EXPAND_SUPPORTED
\r
1000 png_ptr->transformations |= PNG_EXPAND;
\r
1003 /* Make this an error in 1.6 because otherwise the application may assume
\r
1004 * that it just worked and get a memory overwrite.
\r
1006 png_error(png_ptr,
\r
1007 "Cannot do RGB_TO_GRAY without EXPAND_SUPPORTED");
\r
1009 /* png_ptr->transformations &= ~PNG_RGB_TO_GRAY; */
\r
1013 if (red >= 0 && green >= 0 && red + green <= PNG_FP_1)
\r
1015 png_uint_16 red_int, green_int;
\r
1017 /* NOTE: this calculation does not round, but this behavior is retained
\r
1018 * for consistency; the inaccuracy is very small. The code here always
\r
1019 * overwrites the coefficients, regardless of whether they have been
\r
1020 * defaulted or set already.
\r
1022 red_int = (png_uint_16)(((png_uint_32)red*32768)/100000);
\r
1023 green_int = (png_uint_16)(((png_uint_32)green*32768)/100000);
\r
1025 png_ptr->rgb_to_gray_red_coeff = red_int;
\r
1026 png_ptr->rgb_to_gray_green_coeff = green_int;
\r
1027 png_ptr->rgb_to_gray_coefficients_set = 1;
\r
1032 if (red >= 0 && green >= 0)
\r
1033 png_app_warning(png_ptr,
\r
1034 "ignoring out of range rgb_to_gray coefficients");
\r
1036 /* Use the defaults, from the cHRM chunk if set, else the historical
\r
1037 * values which are close to the sRGB/HDTV/ITU-Rec 709 values. See
\r
1038 * png_do_rgb_to_gray for more discussion of the values. In this case
\r
1039 * the coefficients are not marked as 'set' and are not overwritten if
\r
1040 * something has already provided a default.
\r
1042 if (png_ptr->rgb_to_gray_red_coeff == 0 &&
\r
1043 png_ptr->rgb_to_gray_green_coeff == 0)
\r
1045 png_ptr->rgb_to_gray_red_coeff = 6968;
\r
1046 png_ptr->rgb_to_gray_green_coeff = 23434;
\r
1047 /* png_ptr->rgb_to_gray_blue_coeff = 2366; */
\r
1053 #ifdef PNG_FLOATING_POINT_SUPPORTED
\r
1054 /* Convert a RGB image to a grayscale of the same width. This allows us,
\r
1055 * for example, to convert a 24 bpp RGB image into an 8 bpp grayscale image.
\r
1059 png_set_rgb_to_gray(png_structrp png_ptr, int error_action, double red,
\r
1062 png_set_rgb_to_gray_fixed(png_ptr, error_action,
\r
1063 png_fixed(png_ptr, red, "rgb to gray red coefficient"),
\r
1064 png_fixed(png_ptr, green, "rgb to gray green coefficient"));
\r
1066 #endif /* FLOATING POINT */
\r
1068 #endif /* RGB_TO_GRAY */
\r
1070 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
\r
1071 defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
\r
1073 png_set_read_user_transform_fn(png_structrp png_ptr, png_user_transform_ptr
\r
1074 read_user_transform_fn)
\r
1076 png_debug(1, "in png_set_read_user_transform_fn");
\r
1078 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
\r
1079 png_ptr->transformations |= PNG_USER_TRANSFORM;
\r
1080 png_ptr->read_user_transform_fn = read_user_transform_fn;
\r
1085 #ifdef PNG_READ_TRANSFORMS_SUPPORTED
\r
1086 #ifdef PNG_READ_GAMMA_SUPPORTED
\r
1087 /* In the case of gamma transformations only do transformations on images where
\r
1088 * the [file] gamma and screen_gamma are not close reciprocals, otherwise it
\r
1089 * slows things down slightly, and also needlessly introduces small errors.
\r
1091 static int /* PRIVATE */
\r
1092 png_gamma_threshold(png_fixed_point screen_gamma, png_fixed_point file_gamma)
\r
1094 /* PNG_GAMMA_THRESHOLD is the threshold for performing gamma
\r
1095 * correction as a difference of the overall transform from 1.0
\r
1097 * We want to compare the threshold with s*f - 1, if we get
\r
1098 * overflow here it is because of wacky gamma values so we
\r
1099 * turn on processing anyway.
\r
1101 png_fixed_point gtest;
\r
1102 return !png_muldiv(>est, screen_gamma, file_gamma, PNG_FP_1) ||
\r
1103 png_gamma_significant(gtest);
\r
1107 /* Initialize everything needed for the read. This includes modifying
\r
1111 /* For the moment 'png_init_palette_transformations' and
\r
1112 * 'png_init_rgb_transformations' only do some flag canceling optimizations.
\r
1113 * The intent is that these two routines should have palette or rgb operations
\r
1114 * extracted from 'png_init_read_transformations'.
\r
1116 static void /* PRIVATE */
\r
1117 png_init_palette_transformations(png_structrp png_ptr)
\r
1119 /* Called to handle the (input) palette case. In png_do_read_transformations
\r
1120 * the first step is to expand the palette if requested, so this code must
\r
1121 * take care to only make changes that are invariant with respect to the
\r
1122 * palette expansion, or only do them if there is no expansion.
\r
1124 * STRIP_ALPHA has already been handled in the caller (by setting num_trans
\r
1127 int input_has_alpha = 0;
\r
1128 int input_has_transparency = 0;
\r
1130 if (png_ptr->num_trans > 0)
\r
1134 /* Ignore if all the entries are opaque (unlikely!) */
\r
1135 for (i=0; i<png_ptr->num_trans; ++i)
\r
1137 if (png_ptr->trans_alpha[i] == 255)
\r
1139 else if (png_ptr->trans_alpha[i] == 0)
\r
1140 input_has_transparency = 1;
\r
1143 input_has_transparency = 1;
\r
1144 input_has_alpha = 1;
\r
1150 /* If no alpha we can optimize. */
\r
1151 if (input_has_alpha == 0)
\r
1153 /* Any alpha means background and associative alpha processing is
\r
1154 * required, however if the alpha is 0 or 1 throughout OPTIMIZE_ALPHA
\r
1155 * and ENCODE_ALPHA are irrelevant.
\r
1157 png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
\r
1158 png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
\r
1160 if (input_has_transparency == 0)
\r
1161 png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND);
\r
1164 #if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
\r
1165 /* png_set_background handling - deals with the complexity of whether the
\r
1166 * background color is in the file format or the screen format in the case
\r
1167 * where an 'expand' will happen.
\r
1170 /* The following code cannot be entered in the alpha pre-multiplication case
\r
1171 * because PNG_BACKGROUND_EXPAND is cancelled below.
\r
1173 if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) != 0 &&
\r
1174 (png_ptr->transformations & PNG_EXPAND) != 0)
\r
1177 png_ptr->background.red =
\r
1178 png_ptr->palette[png_ptr->background.index].red;
\r
1179 png_ptr->background.green =
\r
1180 png_ptr->palette[png_ptr->background.index].green;
\r
1181 png_ptr->background.blue =
\r
1182 png_ptr->palette[png_ptr->background.index].blue;
\r
1184 #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
\r
1185 if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0)
\r
1187 if ((png_ptr->transformations & PNG_EXPAND_tRNS) == 0)
\r
1189 /* Invert the alpha channel (in tRNS) unless the pixels are
\r
1190 * going to be expanded, in which case leave it for later
\r
1192 int i, istop = png_ptr->num_trans;
\r
1194 for (i = 0; i < istop; i++)
\r
1195 png_ptr->trans_alpha[i] =
\r
1196 (png_byte)(255 - png_ptr->trans_alpha[i]);
\r
1199 #endif /* READ_INVERT_ALPHA */
\r
1201 } /* background expand and (therefore) no alpha association. */
\r
1202 #endif /* READ_EXPAND && READ_BACKGROUND */
\r
1205 static void /* PRIVATE */
\r
1206 png_init_rgb_transformations(png_structrp png_ptr)
\r
1208 /* Added to libpng-1.5.4: check the color type to determine whether there
\r
1209 * is any alpha or transparency in the image and simply cancel the
\r
1210 * background and alpha mode stuff if there isn't.
\r
1212 int input_has_alpha = (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0;
\r
1213 int input_has_transparency = png_ptr->num_trans > 0;
\r
1215 /* If no alpha we can optimize. */
\r
1216 if (input_has_alpha == 0)
\r
1218 /* Any alpha means background and associative alpha processing is
\r
1219 * required, however if the alpha is 0 or 1 throughout OPTIMIZE_ALPHA
\r
1220 * and ENCODE_ALPHA are irrelevant.
\r
1222 # ifdef PNG_READ_ALPHA_MODE_SUPPORTED
\r
1223 png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
\r
1224 png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
\r
1227 if (input_has_transparency == 0)
\r
1228 png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND);
\r
1231 #if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
\r
1232 /* png_set_background handling - deals with the complexity of whether the
\r
1233 * background color is in the file format or the screen format in the case
\r
1234 * where an 'expand' will happen.
\r
1237 /* The following code cannot be entered in the alpha pre-multiplication case
\r
1238 * because PNG_BACKGROUND_EXPAND is cancelled below.
\r
1240 if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) != 0 &&
\r
1241 (png_ptr->transformations & PNG_EXPAND) != 0 &&
\r
1242 (png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
\r
1243 /* i.e., GRAY or GRAY_ALPHA */
\r
1246 /* Expand background and tRNS chunks */
\r
1247 int gray = png_ptr->background.gray;
\r
1248 int trans_gray = png_ptr->trans_color.gray;
\r
1250 switch (png_ptr->bit_depth)
\r
1254 trans_gray *= 0xff;
\r
1259 trans_gray *= 0x55;
\r
1264 trans_gray *= 0x11;
\r
1270 /* FALLTHROUGH */ /* (Already 8 bits) */
\r
1273 /* Already a full 16 bits */
\r
1277 png_ptr->background.red = png_ptr->background.green =
\r
1278 png_ptr->background.blue = (png_uint_16)gray;
\r
1280 if ((png_ptr->transformations & PNG_EXPAND_tRNS) == 0)
\r
1282 png_ptr->trans_color.red = png_ptr->trans_color.green =
\r
1283 png_ptr->trans_color.blue = (png_uint_16)trans_gray;
\r
1286 } /* background expand and (therefore) no alpha association. */
\r
1287 #endif /* READ_EXPAND && READ_BACKGROUND */
\r
1290 void /* PRIVATE */
\r
1291 png_init_read_transformations(png_structrp png_ptr)
\r
1293 png_debug(1, "in png_init_read_transformations");
\r
1295 /* This internal function is called from png_read_start_row in pngrutil.c
\r
1296 * and it is called before the 'rowbytes' calculation is done, so the code
\r
1297 * in here can change or update the transformations flags.
\r
1299 * First do updates that do not depend on the details of the PNG image data
\r
1300 * being processed.
\r
1303 #ifdef PNG_READ_GAMMA_SUPPORTED
\r
1304 /* Prior to 1.5.4 these tests were performed from png_set_gamma, 1.5.4 adds
\r
1305 * png_set_alpha_mode and this is another source for a default file gamma so
\r
1306 * the test needs to be performed later - here. In addition prior to 1.5.4
\r
1307 * the tests were repeated for the PALETTE color type here - this is no
\r
1308 * longer necessary (and doesn't seem to have been necessary before.)
\r
1311 /* The following temporary indicates if overall gamma correction is
\r
1314 int gamma_correction = 0;
\r
1316 if (png_ptr->colorspace.gamma != 0) /* has been set */
\r
1318 if (png_ptr->screen_gamma != 0) /* screen set too */
\r
1319 gamma_correction = png_gamma_threshold(png_ptr->colorspace.gamma,
\r
1320 png_ptr->screen_gamma);
\r
1323 /* Assume the output matches the input; a long time default behavior
\r
1324 * of libpng, although the standard has nothing to say about this.
\r
1326 png_ptr->screen_gamma = png_reciprocal(png_ptr->colorspace.gamma);
\r
1329 else if (png_ptr->screen_gamma != 0)
\r
1330 /* The converse - assume the file matches the screen, note that this
\r
1331 * perhaps undesirable default can (from 1.5.4) be changed by calling
\r
1332 * png_set_alpha_mode (even if the alpha handling mode isn't required
\r
1333 * or isn't changed from the default.)
\r
1335 png_ptr->colorspace.gamma = png_reciprocal(png_ptr->screen_gamma);
\r
1337 else /* neither are set */
\r
1338 /* Just in case the following prevents any processing - file and screen
\r
1339 * are both assumed to be linear and there is no way to introduce a
\r
1340 * third gamma value other than png_set_background with 'UNIQUE', and,
\r
1343 png_ptr->screen_gamma = png_ptr->colorspace.gamma = PNG_FP_1;
\r
1345 /* We have a gamma value now. */
\r
1346 png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
\r
1348 /* Now turn the gamma transformation on or off as appropriate. Notice
\r
1349 * that PNG_GAMMA just refers to the file->screen correction. Alpha
\r
1350 * composition may independently cause gamma correction because it needs
\r
1351 * linear data (e.g. if the file has a gAMA chunk but the screen gamma
\r
1352 * hasn't been specified.) In any case this flag may get turned off in
\r
1353 * the code immediately below if the transform can be handled outside the
\r
1356 if (gamma_correction != 0)
\r
1357 png_ptr->transformations |= PNG_GAMMA;
\r
1360 png_ptr->transformations &= ~PNG_GAMMA;
\r
1364 /* Certain transformations have the effect of preventing other
\r
1365 * transformations that happen afterward in png_do_read_transformations;
\r
1366 * resolve the interdependencies here. From the code of
\r
1367 * png_do_read_transformations the order is:
\r
1369 * 1) PNG_EXPAND (including PNG_EXPAND_tRNS)
\r
1370 * 2) PNG_STRIP_ALPHA (if no compose)
\r
1371 * 3) PNG_RGB_TO_GRAY
\r
1372 * 4) PNG_GRAY_TO_RGB iff !PNG_BACKGROUND_IS_GRAY
\r
1375 * 7) PNG_STRIP_ALPHA (if compose)
\r
1376 * 8) PNG_ENCODE_ALPHA
\r
1377 * 9) PNG_SCALE_16_TO_8
\r
1379 * 11) PNG_QUANTIZE (converts to palette)
\r
1380 * 12) PNG_EXPAND_16
\r
1381 * 13) PNG_GRAY_TO_RGB iff PNG_BACKGROUND_IS_GRAY
\r
1382 * 14) PNG_INVERT_MONO
\r
1383 * 15) PNG_INVERT_ALPHA
\r
1387 * 19) PNG_PACKSWAP
\r
1388 * 20) PNG_FILLER (includes PNG_ADD_ALPHA)
\r
1389 * 21) PNG_SWAP_ALPHA
\r
1390 * 22) PNG_SWAP_BYTES
\r
1391 * 23) PNG_USER_TRANSFORM [must be last]
\r
1393 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
\r
1394 if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0 &&
\r
1395 (png_ptr->transformations & PNG_COMPOSE) == 0)
\r
1397 /* Stripping the alpha channel happens immediately after the 'expand'
\r
1398 * transformations, before all other transformation, so it cancels out
\r
1399 * the alpha handling. It has the side effect negating the effect of
\r
1400 * PNG_EXPAND_tRNS too:
\r
1402 png_ptr->transformations &= ~(PNG_BACKGROUND_EXPAND | PNG_ENCODE_ALPHA |
\r
1404 png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
\r
1406 /* Kill the tRNS chunk itself too. Prior to 1.5.4 this did not happen
\r
1407 * so transparency information would remain just so long as it wasn't
\r
1408 * expanded. This produces unexpected API changes if the set of things
\r
1409 * that do PNG_EXPAND_tRNS changes (perfectly possible given the
\r
1410 * documentation - which says ask for what you want, accept what you
\r
1411 * get.) This makes the behavior consistent from 1.5.4:
\r
1413 png_ptr->num_trans = 0;
\r
1415 #endif /* STRIP_ALPHA supported, no COMPOSE */
\r
1417 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
\r
1418 /* If the screen gamma is about 1.0 then the OPTIMIZE_ALPHA and ENCODE_ALPHA
\r
1419 * settings will have no effect.
\r
1421 if (png_gamma_significant(png_ptr->screen_gamma) == 0)
\r
1423 png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
\r
1424 png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
\r
1428 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
\r
1429 /* Make sure the coefficients for the rgb to gray conversion are set
\r
1432 if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
\r
1433 png_colorspace_set_rgb_coefficients(png_ptr);
\r
1436 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
\r
1437 #if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
\r
1438 /* Detect gray background and attempt to enable optimization for
\r
1439 * gray --> RGB case.
\r
1441 * Note: if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or
\r
1442 * RGB_ALPHA (in which case need_expand is superfluous anyway), the
\r
1443 * background color might actually be gray yet not be flagged as such.
\r
1444 * This is not a problem for the current code, which uses
\r
1445 * PNG_BACKGROUND_IS_GRAY only to decide when to do the
\r
1446 * png_do_gray_to_rgb() transformation.
\r
1448 * TODO: this code needs to be revised to avoid the complexity and
\r
1449 * interdependencies. The color type of the background should be recorded in
\r
1450 * png_set_background, along with the bit depth, then the code has a record
\r
1451 * of exactly what color space the background is currently in.
\r
1453 if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) != 0)
\r
1455 /* PNG_BACKGROUND_EXPAND: the background is in the file color space, so if
\r
1456 * the file was grayscale the background value is gray.
\r
1458 if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
\r
1459 png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
\r
1462 else if ((png_ptr->transformations & PNG_COMPOSE) != 0)
\r
1464 /* PNG_COMPOSE: png_set_background was called with need_expand false,
\r
1465 * so the color is in the color space of the output or png_set_alpha_mode
\r
1466 * was called and the color is black. Ignore RGB_TO_GRAY because that
\r
1467 * happens before GRAY_TO_RGB.
\r
1469 if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0)
\r
1471 if (png_ptr->background.red == png_ptr->background.green &&
\r
1472 png_ptr->background.red == png_ptr->background.blue)
\r
1474 png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
\r
1475 png_ptr->background.gray = png_ptr->background.red;
\r
1479 #endif /* READ_EXPAND && READ_BACKGROUND */
\r
1480 #endif /* READ_GRAY_TO_RGB */
\r
1482 /* For indexed PNG data (PNG_COLOR_TYPE_PALETTE) many of the transformations
\r
1483 * can be performed directly on the palette, and some (such as rgb to gray)
\r
1484 * can be optimized inside the palette. This is particularly true of the
\r
1485 * composite (background and alpha) stuff, which can be pretty much all done
\r
1486 * in the palette even if the result is expanded to RGB or gray afterward.
\r
1488 * NOTE: this is Not Yet Implemented, the code behaves as in 1.5.1 and
\r
1489 * earlier and the palette stuff is actually handled on the first row. This
\r
1490 * leads to the reported bug that the palette returned by png_get_PLTE is not
\r
1493 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
\r
1494 png_init_palette_transformations(png_ptr);
\r
1497 png_init_rgb_transformations(png_ptr);
\r
1499 #if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
\r
1500 defined(PNG_READ_EXPAND_16_SUPPORTED)
\r
1501 if ((png_ptr->transformations & PNG_EXPAND_16) != 0 &&
\r
1502 (png_ptr->transformations & PNG_COMPOSE) != 0 &&
\r
1503 (png_ptr->transformations & PNG_BACKGROUND_EXPAND) == 0 &&
\r
1504 png_ptr->bit_depth != 16)
\r
1506 /* TODO: fix this. Because the expand_16 operation is after the compose
\r
1507 * handling the background color must be 8, not 16, bits deep, but the
\r
1508 * application will supply a 16-bit value so reduce it here.
\r
1510 * The PNG_BACKGROUND_EXPAND code above does not expand to 16 bits at
\r
1511 * present, so that case is ok (until do_expand_16 is moved.)
\r
1513 * NOTE: this discards the low 16 bits of the user supplied background
\r
1514 * color, but until expand_16 works properly there is no choice!
\r
1516 # define CHOP(x) (x)=((png_uint_16)PNG_DIV257(x))
\r
1517 CHOP(png_ptr->background.red);
\r
1518 CHOP(png_ptr->background.green);
\r
1519 CHOP(png_ptr->background.blue);
\r
1520 CHOP(png_ptr->background.gray);
\r
1523 #endif /* READ_BACKGROUND && READ_EXPAND_16 */
\r
1525 #if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
\r
1526 (defined(PNG_READ_SCALE_16_TO_8_SUPPORTED) || \
\r
1527 defined(PNG_READ_STRIP_16_TO_8_SUPPORTED))
\r
1528 if ((png_ptr->transformations & (PNG_16_TO_8|PNG_SCALE_16_TO_8)) != 0 &&
\r
1529 (png_ptr->transformations & PNG_COMPOSE) != 0 &&
\r
1530 (png_ptr->transformations & PNG_BACKGROUND_EXPAND) == 0 &&
\r
1531 png_ptr->bit_depth == 16)
\r
1533 /* On the other hand, if a 16-bit file is to be reduced to 8-bits per
\r
1534 * component this will also happen after PNG_COMPOSE and so the background
\r
1535 * color must be pre-expanded here.
\r
1537 * TODO: fix this too.
\r
1539 png_ptr->background.red = (png_uint_16)(png_ptr->background.red * 257);
\r
1540 png_ptr->background.green =
\r
1541 (png_uint_16)(png_ptr->background.green * 257);
\r
1542 png_ptr->background.blue = (png_uint_16)(png_ptr->background.blue * 257);
\r
1543 png_ptr->background.gray = (png_uint_16)(png_ptr->background.gray * 257);
\r
1547 /* NOTE: below 'PNG_READ_ALPHA_MODE_SUPPORTED' is presumed to also enable the
\r
1548 * background support (see the comments in scripts/pnglibconf.dfa), this
\r
1549 * allows pre-multiplication of the alpha channel to be implemented as
\r
1550 * compositing on black. This is probably sub-optimal and has been done in
\r
1551 * 1.5.4 betas simply to enable external critique and testing (i.e. to
\r
1552 * implement the new API quickly, without lots of internal changes.)
\r
1555 #ifdef PNG_READ_GAMMA_SUPPORTED
\r
1556 # ifdef PNG_READ_BACKGROUND_SUPPORTED
\r
1557 /* Includes ALPHA_MODE */
\r
1558 png_ptr->background_1 = png_ptr->background;
\r
1561 /* This needs to change - in the palette image case a whole set of tables are
\r
1562 * built when it would be quicker to just calculate the correct value for
\r
1563 * each palette entry directly. Also, the test is too tricky - why check
\r
1564 * PNG_RGB_TO_GRAY if PNG_GAMMA is not set? The answer seems to be that
\r
1565 * PNG_GAMMA is cancelled even if the gamma is known? The test excludes the
\r
1566 * PNG_COMPOSE case, so apparently if there is no *overall* gamma correction
\r
1567 * the gamma tables will not be built even if composition is required on a
\r
1568 * gamma encoded value.
\r
1570 * In 1.5.4 this is addressed below by an additional check on the individual
\r
1571 * file gamma - if it is not 1.0 both RGB_TO_GRAY and COMPOSE need the
\r
1574 if ((png_ptr->transformations & PNG_GAMMA) != 0 ||
\r
1575 ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0 &&
\r
1576 (png_gamma_significant(png_ptr->colorspace.gamma) != 0 ||
\r
1577 png_gamma_significant(png_ptr->screen_gamma) != 0)) ||
\r
1578 ((png_ptr->transformations & PNG_COMPOSE) != 0 &&
\r
1579 (png_gamma_significant(png_ptr->colorspace.gamma) != 0 ||
\r
1580 png_gamma_significant(png_ptr->screen_gamma) != 0
\r
1581 # ifdef PNG_READ_BACKGROUND_SUPPORTED
\r
1582 || (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_UNIQUE &&
\r
1583 png_gamma_significant(png_ptr->background_gamma) != 0)
\r
1585 )) || ((png_ptr->transformations & PNG_ENCODE_ALPHA) != 0 &&
\r
1586 png_gamma_significant(png_ptr->screen_gamma) != 0))
\r
1588 png_build_gamma_table(png_ptr, png_ptr->bit_depth);
\r
1590 #ifdef PNG_READ_BACKGROUND_SUPPORTED
\r
1591 if ((png_ptr->transformations & PNG_COMPOSE) != 0)
\r
1593 /* Issue a warning about this combination: because RGB_TO_GRAY is
\r
1594 * optimized to do the gamma transform if present yet do_background has
\r
1595 * to do the same thing if both options are set a
\r
1596 * double-gamma-correction happens. This is true in all versions of
\r
1599 if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
\r
1600 png_warning(png_ptr,
\r
1601 "libpng does not support gamma+background+rgb_to_gray");
\r
1603 if ((png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) != 0)
\r
1605 /* We don't get to here unless there is a tRNS chunk with non-opaque
\r
1606 * entries - see the checking code at the start of this function.
\r
1608 png_color back, back_1;
\r
1609 png_colorp palette = png_ptr->palette;
\r
1610 int num_palette = png_ptr->num_palette;
\r
1612 if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_FILE)
\r
1615 back.red = png_ptr->gamma_table[png_ptr->background.red];
\r
1616 back.green = png_ptr->gamma_table[png_ptr->background.green];
\r
1617 back.blue = png_ptr->gamma_table[png_ptr->background.blue];
\r
1619 back_1.red = png_ptr->gamma_to_1[png_ptr->background.red];
\r
1620 back_1.green = png_ptr->gamma_to_1[png_ptr->background.green];
\r
1621 back_1.blue = png_ptr->gamma_to_1[png_ptr->background.blue];
\r
1625 png_fixed_point g, gs;
\r
1627 switch (png_ptr->background_gamma_type)
\r
1629 case PNG_BACKGROUND_GAMMA_SCREEN:
\r
1630 g = (png_ptr->screen_gamma);
\r
1634 case PNG_BACKGROUND_GAMMA_FILE:
\r
1635 g = png_reciprocal(png_ptr->colorspace.gamma);
\r
1636 gs = png_reciprocal2(png_ptr->colorspace.gamma,
\r
1637 png_ptr->screen_gamma);
\r
1640 case PNG_BACKGROUND_GAMMA_UNIQUE:
\r
1641 g = png_reciprocal(png_ptr->background_gamma);
\r
1642 gs = png_reciprocal2(png_ptr->background_gamma,
\r
1643 png_ptr->screen_gamma);
\r
1646 g = PNG_FP_1; /* back_1 */
\r
1647 gs = PNG_FP_1; /* back */
\r
1651 if (png_gamma_significant(gs) != 0)
\r
1653 back.red = png_gamma_8bit_correct(png_ptr->background.red,
\r
1655 back.green = png_gamma_8bit_correct(png_ptr->background.green,
\r
1657 back.blue = png_gamma_8bit_correct(png_ptr->background.blue,
\r
1663 back.red = (png_byte)png_ptr->background.red;
\r
1664 back.green = (png_byte)png_ptr->background.green;
\r
1665 back.blue = (png_byte)png_ptr->background.blue;
\r
1668 if (png_gamma_significant(g) != 0)
\r
1670 back_1.red = png_gamma_8bit_correct(png_ptr->background.red,
\r
1672 back_1.green = png_gamma_8bit_correct(
\r
1673 png_ptr->background.green, g);
\r
1674 back_1.blue = png_gamma_8bit_correct(png_ptr->background.blue,
\r
1680 back_1.red = (png_byte)png_ptr->background.red;
\r
1681 back_1.green = (png_byte)png_ptr->background.green;
\r
1682 back_1.blue = (png_byte)png_ptr->background.blue;
\r
1686 for (i = 0; i < num_palette; i++)
\r
1688 if (i < (int)png_ptr->num_trans &&
\r
1689 png_ptr->trans_alpha[i] != 0xff)
\r
1691 if (png_ptr->trans_alpha[i] == 0)
\r
1693 palette[i] = back;
\r
1695 else /* if (png_ptr->trans_alpha[i] != 0xff) */
\r
1699 v = png_ptr->gamma_to_1[palette[i].red];
\r
1700 png_composite(w, v, png_ptr->trans_alpha[i], back_1.red);
\r
1701 palette[i].red = png_ptr->gamma_from_1[w];
\r
1703 v = png_ptr->gamma_to_1[palette[i].green];
\r
1704 png_composite(w, v, png_ptr->trans_alpha[i], back_1.green);
\r
1705 palette[i].green = png_ptr->gamma_from_1[w];
\r
1707 v = png_ptr->gamma_to_1[palette[i].blue];
\r
1708 png_composite(w, v, png_ptr->trans_alpha[i], back_1.blue);
\r
1709 palette[i].blue = png_ptr->gamma_from_1[w];
\r
1714 palette[i].red = png_ptr->gamma_table[palette[i].red];
\r
1715 palette[i].green = png_ptr->gamma_table[palette[i].green];
\r
1716 palette[i].blue = png_ptr->gamma_table[palette[i].blue];
\r
1720 /* Prevent the transformations being done again.
\r
1722 * NOTE: this is highly dubious; it removes the transformations in
\r
1723 * place. This seems inconsistent with the general treatment of the
\r
1724 * transformations elsewhere.
\r
1726 png_ptr->transformations &= ~(PNG_COMPOSE | PNG_GAMMA);
\r
1727 } /* color_type == PNG_COLOR_TYPE_PALETTE */
\r
1729 /* if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN) */
\r
1730 else /* color_type != PNG_COLOR_TYPE_PALETTE */
\r
1732 int gs_sig, g_sig;
\r
1733 png_fixed_point g = PNG_FP_1; /* Correction to linear */
\r
1734 png_fixed_point gs = PNG_FP_1; /* Correction to screen */
\r
1736 switch (png_ptr->background_gamma_type)
\r
1738 case PNG_BACKGROUND_GAMMA_SCREEN:
\r
1739 g = png_ptr->screen_gamma;
\r
1740 /* gs = PNG_FP_1; */
\r
1743 case PNG_BACKGROUND_GAMMA_FILE:
\r
1744 g = png_reciprocal(png_ptr->colorspace.gamma);
\r
1745 gs = png_reciprocal2(png_ptr->colorspace.gamma,
\r
1746 png_ptr->screen_gamma);
\r
1749 case PNG_BACKGROUND_GAMMA_UNIQUE:
\r
1750 g = png_reciprocal(png_ptr->background_gamma);
\r
1751 gs = png_reciprocal2(png_ptr->background_gamma,
\r
1752 png_ptr->screen_gamma);
\r
1756 png_error(png_ptr, "invalid background gamma type");
\r
1759 g_sig = png_gamma_significant(g);
\r
1760 gs_sig = png_gamma_significant(gs);
\r
1763 png_ptr->background_1.gray = png_gamma_correct(png_ptr,
\r
1764 png_ptr->background.gray, g);
\r
1767 png_ptr->background.gray = png_gamma_correct(png_ptr,
\r
1768 png_ptr->background.gray, gs);
\r
1770 if ((png_ptr->background.red != png_ptr->background.green) ||
\r
1771 (png_ptr->background.red != png_ptr->background.blue) ||
\r
1772 (png_ptr->background.red != png_ptr->background.gray))
\r
1774 /* RGB or RGBA with color background */
\r
1777 png_ptr->background_1.red = png_gamma_correct(png_ptr,
\r
1778 png_ptr->background.red, g);
\r
1780 png_ptr->background_1.green = png_gamma_correct(png_ptr,
\r
1781 png_ptr->background.green, g);
\r
1783 png_ptr->background_1.blue = png_gamma_correct(png_ptr,
\r
1784 png_ptr->background.blue, g);
\r
1789 png_ptr->background.red = png_gamma_correct(png_ptr,
\r
1790 png_ptr->background.red, gs);
\r
1792 png_ptr->background.green = png_gamma_correct(png_ptr,
\r
1793 png_ptr->background.green, gs);
\r
1795 png_ptr->background.blue = png_gamma_correct(png_ptr,
\r
1796 png_ptr->background.blue, gs);
\r
1802 /* GRAY, GRAY ALPHA, RGB, or RGBA with gray background */
\r
1803 png_ptr->background_1.red = png_ptr->background_1.green
\r
1804 = png_ptr->background_1.blue = png_ptr->background_1.gray;
\r
1806 png_ptr->background.red = png_ptr->background.green
\r
1807 = png_ptr->background.blue = png_ptr->background.gray;
\r
1810 /* The background is now in screen gamma: */
\r
1811 png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_SCREEN;
\r
1812 } /* color_type != PNG_COLOR_TYPE_PALETTE */
\r
1813 }/* png_ptr->transformations & PNG_BACKGROUND */
\r
1816 /* Transformation does not include PNG_BACKGROUND */
\r
1817 #endif /* READ_BACKGROUND */
\r
1818 if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE
\r
1819 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
\r
1820 /* RGB_TO_GRAY needs to have non-gamma-corrected values! */
\r
1821 && ((png_ptr->transformations & PNG_EXPAND) == 0 ||
\r
1822 (png_ptr->transformations & PNG_RGB_TO_GRAY) == 0)
\r
1826 png_colorp palette = png_ptr->palette;
\r
1827 int num_palette = png_ptr->num_palette;
\r
1830 /* NOTE: there are other transformations that should probably be in
\r
1833 for (i = 0; i < num_palette; i++)
\r
1835 palette[i].red = png_ptr->gamma_table[palette[i].red];
\r
1836 palette[i].green = png_ptr->gamma_table[palette[i].green];
\r
1837 palette[i].blue = png_ptr->gamma_table[palette[i].blue];
\r
1840 /* Done the gamma correction. */
\r
1841 png_ptr->transformations &= ~PNG_GAMMA;
\r
1842 } /* color_type == PALETTE && !PNG_BACKGROUND transformation */
\r
1844 #ifdef PNG_READ_BACKGROUND_SUPPORTED
\r
1847 #endif /* READ_GAMMA */
\r
1849 #ifdef PNG_READ_BACKGROUND_SUPPORTED
\r
1850 /* No GAMMA transformation (see the hanging else 4 lines above) */
\r
1851 if ((png_ptr->transformations & PNG_COMPOSE) != 0 &&
\r
1852 (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
\r
1855 int istop = (int)png_ptr->num_trans;
\r
1857 png_colorp palette = png_ptr->palette;
\r
1859 back.red = (png_byte)png_ptr->background.red;
\r
1860 back.green = (png_byte)png_ptr->background.green;
\r
1861 back.blue = (png_byte)png_ptr->background.blue;
\r
1863 for (i = 0; i < istop; i++)
\r
1865 if (png_ptr->trans_alpha[i] == 0)
\r
1867 palette[i] = back;
\r
1870 else if (png_ptr->trans_alpha[i] != 0xff)
\r
1872 /* The png_composite() macro is defined in png.h */
\r
1873 png_composite(palette[i].red, palette[i].red,
\r
1874 png_ptr->trans_alpha[i], back.red);
\r
1876 png_composite(palette[i].green, palette[i].green,
\r
1877 png_ptr->trans_alpha[i], back.green);
\r
1879 png_composite(palette[i].blue, palette[i].blue,
\r
1880 png_ptr->trans_alpha[i], back.blue);
\r
1884 png_ptr->transformations &= ~PNG_COMPOSE;
\r
1886 #endif /* READ_BACKGROUND */
\r
1888 #ifdef PNG_READ_SHIFT_SUPPORTED
\r
1889 if ((png_ptr->transformations & PNG_SHIFT) != 0 &&
\r
1890 (png_ptr->transformations & PNG_EXPAND) == 0 &&
\r
1891 (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
\r
1894 int istop = png_ptr->num_palette;
\r
1895 int shift = 8 - png_ptr->sig_bit.red;
\r
1897 png_ptr->transformations &= ~PNG_SHIFT;
\r
1899 /* significant bits can be in the range 1 to 7 for a meaningful result, if
\r
1900 * the number of significant bits is 0 then no shift is done (this is an
\r
1901 * error condition which is silently ignored.)
\r
1903 if (shift > 0 && shift < 8)
\r
1904 for (i=0; i<istop; ++i)
\r
1906 int component = png_ptr->palette[i].red;
\r
1908 component >>= shift;
\r
1909 png_ptr->palette[i].red = (png_byte)component;
\r
1912 shift = 8 - png_ptr->sig_bit.green;
\r
1913 if (shift > 0 && shift < 8)
\r
1914 for (i=0; i<istop; ++i)
\r
1916 int component = png_ptr->palette[i].green;
\r
1918 component >>= shift;
\r
1919 png_ptr->palette[i].green = (png_byte)component;
\r
1922 shift = 8 - png_ptr->sig_bit.blue;
\r
1923 if (shift > 0 && shift < 8)
\r
1924 for (i=0; i<istop; ++i)
\r
1926 int component = png_ptr->palette[i].blue;
\r
1928 component >>= shift;
\r
1929 png_ptr->palette[i].blue = (png_byte)component;
\r
1932 #endif /* READ_SHIFT */
\r
1935 /* Modify the info structure to reflect the transformations. The
\r
1936 * info should be updated so a PNG file could be written with it,
\r
1937 * assuming the transformations result in valid PNG data.
\r
1939 void /* PRIVATE */
\r
1940 png_read_transform_info(png_structrp png_ptr, png_inforp info_ptr)
\r
1942 png_debug(1, "in png_read_transform_info");
\r
1944 #ifdef PNG_READ_EXPAND_SUPPORTED
\r
1945 if ((png_ptr->transformations & PNG_EXPAND) != 0)
\r
1947 if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
\r
1949 /* This check must match what actually happens in
\r
1950 * png_do_expand_palette; if it ever checks the tRNS chunk to see if
\r
1951 * it is all opaque we must do the same (at present it does not.)
\r
1953 if (png_ptr->num_trans > 0)
\r
1954 info_ptr->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
\r
1957 info_ptr->color_type = PNG_COLOR_TYPE_RGB;
\r
1959 info_ptr->bit_depth = 8;
\r
1960 info_ptr->num_trans = 0;
\r
1962 if (png_ptr->palette == NULL)
\r
1963 png_error (png_ptr, "Palette is NULL in indexed image");
\r
1967 if (png_ptr->num_trans != 0)
\r
1969 if ((png_ptr->transformations & PNG_EXPAND_tRNS) != 0)
\r
1970 info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
\r
1972 if (info_ptr->bit_depth < 8)
\r
1973 info_ptr->bit_depth = 8;
\r
1975 info_ptr->num_trans = 0;
\r
1980 #if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
\r
1981 defined(PNG_READ_ALPHA_MODE_SUPPORTED)
\r
1982 /* The following is almost certainly wrong unless the background value is in
\r
1983 * the screen space!
\r
1985 if ((png_ptr->transformations & PNG_COMPOSE) != 0)
\r
1986 info_ptr->background = png_ptr->background;
\r
1989 #ifdef PNG_READ_GAMMA_SUPPORTED
\r
1990 /* The following used to be conditional on PNG_GAMMA (prior to 1.5.4),
\r
1991 * however it seems that the code in png_init_read_transformations, which has
\r
1992 * been called before this from png_read_update_info->png_read_start_row
\r
1993 * sometimes does the gamma transform and cancels the flag.
\r
1995 * TODO: this looks wrong; the info_ptr should end up with a gamma equal to
\r
1996 * the screen_gamma value. The following probably results in weirdness if
\r
1997 * the info_ptr is used by the app after the rows have been read.
\r
1999 info_ptr->colorspace.gamma = png_ptr->colorspace.gamma;
\r
2002 if (info_ptr->bit_depth == 16)
\r
2004 # ifdef PNG_READ_16BIT_SUPPORTED
\r
2005 # ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
\r
2006 if ((png_ptr->transformations & PNG_SCALE_16_TO_8) != 0)
\r
2007 info_ptr->bit_depth = 8;
\r
2010 # ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
\r
2011 if ((png_ptr->transformations & PNG_16_TO_8) != 0)
\r
2012 info_ptr->bit_depth = 8;
\r
2016 /* No 16-bit support: force chopping 16-bit input down to 8, in this case
\r
2017 * the app program can chose if both APIs are available by setting the
\r
2018 * correct scaling to use.
\r
2020 # ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
\r
2021 /* For compatibility with previous versions use the strip method by
\r
2022 * default. This code works because if PNG_SCALE_16_TO_8 is already
\r
2023 * set the code below will do that in preference to the chop.
\r
2025 png_ptr->transformations |= PNG_16_TO_8;
\r
2026 info_ptr->bit_depth = 8;
\r
2029 # ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
\r
2030 png_ptr->transformations |= PNG_SCALE_16_TO_8;
\r
2031 info_ptr->bit_depth = 8;
\r
2034 CONFIGURATION ERROR: you must enable at least one 16 to 8 method
\r
2037 #endif /* !READ_16BIT */
\r
2040 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
\r
2041 if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0)
\r
2042 info_ptr->color_type = (png_byte)(info_ptr->color_type |
\r
2043 PNG_COLOR_MASK_COLOR);
\r
2046 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
\r
2047 if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
\r
2048 info_ptr->color_type = (png_byte)(info_ptr->color_type &
\r
2049 ~PNG_COLOR_MASK_COLOR);
\r
2052 #ifdef PNG_READ_QUANTIZE_SUPPORTED
\r
2053 if ((png_ptr->transformations & PNG_QUANTIZE) != 0)
\r
2055 if (((info_ptr->color_type == PNG_COLOR_TYPE_RGB) ||
\r
2056 (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)) &&
\r
2057 png_ptr->palette_lookup != 0 && info_ptr->bit_depth == 8)
\r
2059 info_ptr->color_type = PNG_COLOR_TYPE_PALETTE;
\r
2064 #ifdef PNG_READ_EXPAND_16_SUPPORTED
\r
2065 if ((png_ptr->transformations & PNG_EXPAND_16) != 0 &&
\r
2066 info_ptr->bit_depth == 8 &&
\r
2067 info_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
\r
2069 info_ptr->bit_depth = 16;
\r
2073 #ifdef PNG_READ_PACK_SUPPORTED
\r
2074 if ((png_ptr->transformations & PNG_PACK) != 0 &&
\r
2075 (info_ptr->bit_depth < 8))
\r
2076 info_ptr->bit_depth = 8;
\r
2079 if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
\r
2080 info_ptr->channels = 1;
\r
2082 else if ((info_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
\r
2083 info_ptr->channels = 3;
\r
2086 info_ptr->channels = 1;
\r
2088 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
\r
2089 if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0)
\r
2091 info_ptr->color_type = (png_byte)(info_ptr->color_type &
\r
2092 ~PNG_COLOR_MASK_ALPHA);
\r
2093 info_ptr->num_trans = 0;
\r
2097 if ((info_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
\r
2098 info_ptr->channels++;
\r
2100 #ifdef PNG_READ_FILLER_SUPPORTED
\r
2101 /* STRIP_ALPHA and FILLER allowed: MASK_ALPHA bit stripped above */
\r
2102 if ((png_ptr->transformations & PNG_FILLER) != 0 &&
\r
2103 (info_ptr->color_type == PNG_COLOR_TYPE_RGB ||
\r
2104 info_ptr->color_type == PNG_COLOR_TYPE_GRAY))
\r
2106 info_ptr->channels++;
\r
2107 /* If adding a true alpha channel not just filler */
\r
2108 if ((png_ptr->transformations & PNG_ADD_ALPHA) != 0)
\r
2109 info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
\r
2113 #if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) && \
\r
2114 defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
\r
2115 if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
\r
2117 if (png_ptr->user_transform_depth != 0)
\r
2118 info_ptr->bit_depth = png_ptr->user_transform_depth;
\r
2120 if (png_ptr->user_transform_channels != 0)
\r
2121 info_ptr->channels = png_ptr->user_transform_channels;
\r
2125 info_ptr->pixel_depth = (png_byte)(info_ptr->channels *
\r
2126 info_ptr->bit_depth);
\r
2128 info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, info_ptr->width);
\r
2130 /* Adding in 1.5.4: cache the above value in png_struct so that we can later
\r
2131 * check in png_rowbytes that the user buffer won't get overwritten. Note
\r
2132 * that the field is not always set - if png_read_update_info isn't called
\r
2133 * the application has to either not do any transforms or get the calculation
\r
2136 png_ptr->info_rowbytes = info_ptr->rowbytes;
\r
2138 #ifndef PNG_READ_EXPAND_SUPPORTED
\r
2139 if (png_ptr != NULL)
\r
2144 #ifdef PNG_READ_PACK_SUPPORTED
\r
2145 /* Unpack pixels of 1, 2, or 4 bits per pixel into 1 byte per pixel,
\r
2146 * without changing the actual values. Thus, if you had a row with
\r
2147 * a bit depth of 1, you would end up with bytes that only contained
\r
2148 * the numbers 0 or 1. If you would rather they contain 0 and 255, use
\r
2149 * png_do_shift() after this.
\r
2152 png_do_unpack(png_row_infop row_info, png_bytep row)
\r
2154 png_debug(1, "in png_do_unpack");
\r
2156 if (row_info->bit_depth < 8)
\r
2159 png_uint_32 row_width=row_info->width;
\r
2161 switch (row_info->bit_depth)
\r
2165 png_bytep sp = row + (size_t)((row_width - 1) >> 3);
\r
2166 png_bytep dp = row + (size_t)row_width - 1;
\r
2167 png_uint_32 shift = 7U - ((row_width + 7U) & 0x07);
\r
2168 for (i = 0; i < row_width; i++)
\r
2170 *dp = (png_byte)((*sp >> shift) & 0x01);
\r
2189 png_bytep sp = row + (size_t)((row_width - 1) >> 2);
\r
2190 png_bytep dp = row + (size_t)row_width - 1;
\r
2191 png_uint_32 shift = ((3U - ((row_width + 3U) & 0x03)) << 1);
\r
2192 for (i = 0; i < row_width; i++)
\r
2194 *dp = (png_byte)((*sp >> shift) & 0x03);
\r
2212 png_bytep sp = row + (size_t)((row_width - 1) >> 1);
\r
2213 png_bytep dp = row + (size_t)row_width - 1;
\r
2214 png_uint_32 shift = ((1U - ((row_width + 1U) & 0x01)) << 2);
\r
2215 for (i = 0; i < row_width; i++)
\r
2217 *dp = (png_byte)((*sp >> shift) & 0x0f);
\r
2236 row_info->bit_depth = 8;
\r
2237 row_info->pixel_depth = (png_byte)(8 * row_info->channels);
\r
2238 row_info->rowbytes = row_width * row_info->channels;
\r
2243 #ifdef PNG_READ_SHIFT_SUPPORTED
\r
2244 /* Reverse the effects of png_do_shift. This routine merely shifts the
\r
2245 * pixels back to their significant bits values. Thus, if you have
\r
2246 * a row of bit depth 8, but only 5 are significant, this will shift
\r
2247 * the values back to 0 through 31.
\r
2250 png_do_unshift(png_row_infop row_info, png_bytep row,
\r
2251 png_const_color_8p sig_bits)
\r
2255 png_debug(1, "in png_do_unshift");
\r
2257 /* The palette case has already been handled in the _init routine. */
\r
2258 color_type = row_info->color_type;
\r
2260 if (color_type != PNG_COLOR_TYPE_PALETTE)
\r
2264 int bit_depth = row_info->bit_depth;
\r
2266 if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
\r
2268 shift[channels++] = bit_depth - sig_bits->red;
\r
2269 shift[channels++] = bit_depth - sig_bits->green;
\r
2270 shift[channels++] = bit_depth - sig_bits->blue;
\r
2275 shift[channels++] = bit_depth - sig_bits->gray;
\r
2278 if ((color_type & PNG_COLOR_MASK_ALPHA) != 0)
\r
2280 shift[channels++] = bit_depth - sig_bits->alpha;
\r
2284 int c, have_shift;
\r
2286 for (c = have_shift = 0; c < channels; ++c)
\r
2288 /* A shift of more than the bit depth is an error condition but it
\r
2289 * gets ignored here.
\r
2291 if (shift[c] <= 0 || shift[c] >= bit_depth)
\r
2298 if (have_shift == 0)
\r
2302 switch (bit_depth)
\r
2305 /* Must be 1bpp gray: should not be here! */
\r
2310 /* Must be 2bpp gray */
\r
2311 /* assert(channels == 1 && shift[0] == 1) */
\r
2313 png_bytep bp = row;
\r
2314 png_bytep bp_end = bp + row_info->rowbytes;
\r
2316 while (bp < bp_end)
\r
2318 int b = (*bp >> 1) & 0x55;
\r
2319 *bp++ = (png_byte)b;
\r
2325 /* Must be 4bpp gray */
\r
2326 /* assert(channels == 1) */
\r
2328 png_bytep bp = row;
\r
2329 png_bytep bp_end = bp + row_info->rowbytes;
\r
2330 int gray_shift = shift[0];
\r
2331 int mask = 0xf >> gray_shift;
\r
2333 mask |= mask << 4;
\r
2335 while (bp < bp_end)
\r
2337 int b = (*bp >> gray_shift) & mask;
\r
2338 *bp++ = (png_byte)b;
\r
2344 /* Single byte components, G, GA, RGB, RGBA */
\r
2346 png_bytep bp = row;
\r
2347 png_bytep bp_end = bp + row_info->rowbytes;
\r
2350 while (bp < bp_end)
\r
2352 int b = *bp >> shift[channel];
\r
2353 if (++channel >= channels)
\r
2355 *bp++ = (png_byte)b;
\r
2360 #ifdef PNG_READ_16BIT_SUPPORTED
\r
2362 /* Double byte components, G, GA, RGB, RGBA */
\r
2364 png_bytep bp = row;
\r
2365 png_bytep bp_end = bp + row_info->rowbytes;
\r
2368 while (bp < bp_end)
\r
2370 int value = (bp[0] << 8) + bp[1];
\r
2372 value >>= shift[channel];
\r
2373 if (++channel >= channels)
\r
2375 *bp++ = (png_byte)(value >> 8);
\r
2376 *bp++ = (png_byte)value;
\r
2386 #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
\r
2387 /* Scale rows of bit depth 16 down to 8 accurately */
\r
2389 png_do_scale_16_to_8(png_row_infop row_info, png_bytep row)
\r
2391 png_debug(1, "in png_do_scale_16_to_8");
\r
2393 if (row_info->bit_depth == 16)
\r
2395 png_bytep sp = row; /* source */
\r
2396 png_bytep dp = row; /* destination */
\r
2397 png_bytep ep = sp + row_info->rowbytes; /* end+1 */
\r
2401 /* The input is an array of 16-bit components, these must be scaled to
\r
2402 * 8 bits each. For a 16-bit value V the required value (from the PNG
\r
2403 * specification) is:
\r
2405 * (V * 255) / 65535
\r
2407 * This reduces to round(V / 257), or floor((V + 128.5)/257)
\r
2409 * Represent V as the two byte value vhi.vlo. Make a guess that the
\r
2410 * result is the top byte of V, vhi, then the correction to this value
\r
2413 * error = floor(((V-vhi.vhi) + 128.5) / 257)
\r
2414 * = floor(((vlo-vhi) + 128.5) / 257)
\r
2416 * This can be approximated using integer arithmetic (and a signed
\r
2419 * error = (vlo-vhi+128) >> 8;
\r
2421 * The approximate differs from the exact answer only when (vlo-vhi) is
\r
2422 * 128; it then gives a correction of +1 when the exact correction is
\r
2423 * 0. This gives 128 errors. The exact answer (correct for all 16-bit
\r
2424 * input values) is:
\r
2426 * error = (vlo-vhi+128)*65535 >> 24;
\r
2428 * An alternative arithmetic calculation which also gives no errors is:
\r
2430 * (V * 255 + 32895) >> 16
\r
2433 png_int_32 tmp = *sp++; /* must be signed! */
\r
2434 tmp += (((int)*sp++ - tmp + 128) * 65535) >> 24;
\r
2435 *dp++ = (png_byte)tmp;
\r
2438 row_info->bit_depth = 8;
\r
2439 row_info->pixel_depth = (png_byte)(8 * row_info->channels);
\r
2440 row_info->rowbytes = row_info->width * row_info->channels;
\r
2445 #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
\r
2447 /* Simply discard the low byte. This was the default behavior prior
\r
2448 * to libpng-1.5.4.
\r
2450 png_do_chop(png_row_infop row_info, png_bytep row)
\r
2452 png_debug(1, "in png_do_chop");
\r
2454 if (row_info->bit_depth == 16)
\r
2456 png_bytep sp = row; /* source */
\r
2457 png_bytep dp = row; /* destination */
\r
2458 png_bytep ep = sp + row_info->rowbytes; /* end+1 */
\r
2463 sp += 2; /* skip low byte */
\r
2466 row_info->bit_depth = 8;
\r
2467 row_info->pixel_depth = (png_byte)(8 * row_info->channels);
\r
2468 row_info->rowbytes = row_info->width * row_info->channels;
\r
2473 #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
\r
2475 png_do_read_swap_alpha(png_row_infop row_info, png_bytep row)
\r
2477 png_uint_32 row_width = row_info->width;
\r
2479 png_debug(1, "in png_do_read_swap_alpha");
\r
2481 if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
\r
2483 /* This converts from RGBA to ARGB */
\r
2484 if (row_info->bit_depth == 8)
\r
2486 png_bytep sp = row + row_info->rowbytes;
\r
2487 png_bytep dp = sp;
\r
2491 for (i = 0; i < row_width; i++)
\r
2494 *(--dp) = *(--sp);
\r
2495 *(--dp) = *(--sp);
\r
2496 *(--dp) = *(--sp);
\r
2501 #ifdef PNG_READ_16BIT_SUPPORTED
\r
2502 /* This converts from RRGGBBAA to AARRGGBB */
\r
2505 png_bytep sp = row + row_info->rowbytes;
\r
2506 png_bytep dp = sp;
\r
2510 for (i = 0; i < row_width; i++)
\r
2512 save[0] = *(--sp);
\r
2513 save[1] = *(--sp);
\r
2514 *(--dp) = *(--sp);
\r
2515 *(--dp) = *(--sp);
\r
2516 *(--dp) = *(--sp);
\r
2517 *(--dp) = *(--sp);
\r
2518 *(--dp) = *(--sp);
\r
2519 *(--dp) = *(--sp);
\r
2520 *(--dp) = save[0];
\r
2521 *(--dp) = save[1];
\r
2527 else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
\r
2529 /* This converts from GA to AG */
\r
2530 if (row_info->bit_depth == 8)
\r
2532 png_bytep sp = row + row_info->rowbytes;
\r
2533 png_bytep dp = sp;
\r
2537 for (i = 0; i < row_width; i++)
\r
2540 *(--dp) = *(--sp);
\r
2545 #ifdef PNG_READ_16BIT_SUPPORTED
\r
2546 /* This converts from GGAA to AAGG */
\r
2549 png_bytep sp = row + row_info->rowbytes;
\r
2550 png_bytep dp = sp;
\r
2554 for (i = 0; i < row_width; i++)
\r
2556 save[0] = *(--sp);
\r
2557 save[1] = *(--sp);
\r
2558 *(--dp) = *(--sp);
\r
2559 *(--dp) = *(--sp);
\r
2560 *(--dp) = save[0];
\r
2561 *(--dp) = save[1];
\r
2569 #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
\r
2571 png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)
\r
2573 png_uint_32 row_width;
\r
2574 png_debug(1, "in png_do_read_invert_alpha");
\r
2576 row_width = row_info->width;
\r
2577 if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
\r
2579 if (row_info->bit_depth == 8)
\r
2581 /* This inverts the alpha channel in RGBA */
\r
2582 png_bytep sp = row + row_info->rowbytes;
\r
2583 png_bytep dp = sp;
\r
2586 for (i = 0; i < row_width; i++)
\r
2588 *(--dp) = (png_byte)(255 - *(--sp));
\r
2590 /* This does nothing:
\r
2591 *(--dp) = *(--sp);
\r
2592 *(--dp) = *(--sp);
\r
2593 *(--dp) = *(--sp);
\r
2594 We can replace it with:
\r
2601 #ifdef PNG_READ_16BIT_SUPPORTED
\r
2602 /* This inverts the alpha channel in RRGGBBAA */
\r
2605 png_bytep sp = row + row_info->rowbytes;
\r
2606 png_bytep dp = sp;
\r
2609 for (i = 0; i < row_width; i++)
\r
2611 *(--dp) = (png_byte)(255 - *(--sp));
\r
2612 *(--dp) = (png_byte)(255 - *(--sp));
\r
2614 /* This does nothing:
\r
2615 *(--dp) = *(--sp);
\r
2616 *(--dp) = *(--sp);
\r
2617 *(--dp) = *(--sp);
\r
2618 *(--dp) = *(--sp);
\r
2619 *(--dp) = *(--sp);
\r
2620 *(--dp) = *(--sp);
\r
2621 We can replace it with:
\r
2629 else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
\r
2631 if (row_info->bit_depth == 8)
\r
2633 /* This inverts the alpha channel in GA */
\r
2634 png_bytep sp = row + row_info->rowbytes;
\r
2635 png_bytep dp = sp;
\r
2638 for (i = 0; i < row_width; i++)
\r
2640 *(--dp) = (png_byte)(255 - *(--sp));
\r
2641 *(--dp) = *(--sp);
\r
2645 #ifdef PNG_READ_16BIT_SUPPORTED
\r
2648 /* This inverts the alpha channel in GGAA */
\r
2649 png_bytep sp = row + row_info->rowbytes;
\r
2650 png_bytep dp = sp;
\r
2653 for (i = 0; i < row_width; i++)
\r
2655 *(--dp) = (png_byte)(255 - *(--sp));
\r
2656 *(--dp) = (png_byte)(255 - *(--sp));
\r
2658 *(--dp) = *(--sp);
\r
2659 *(--dp) = *(--sp);
\r
2670 #ifdef PNG_READ_FILLER_SUPPORTED
\r
2671 /* Add filler channel if we have RGB color */
\r
2673 png_do_read_filler(png_row_infop row_info, png_bytep row,
\r
2674 png_uint_32 filler, png_uint_32 flags)
\r
2677 png_uint_32 row_width = row_info->width;
\r
2679 #ifdef PNG_READ_16BIT_SUPPORTED
\r
2680 png_byte hi_filler = (png_byte)(filler>>8);
\r
2682 png_byte lo_filler = (png_byte)filler;
\r
2684 png_debug(1, "in png_do_read_filler");
\r
2687 row_info->color_type == PNG_COLOR_TYPE_GRAY)
\r
2689 if (row_info->bit_depth == 8)
\r
2691 if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
\r
2693 /* This changes the data from G to GX */
\r
2694 png_bytep sp = row + (size_t)row_width;
\r
2695 png_bytep dp = sp + (size_t)row_width;
\r
2696 for (i = 1; i < row_width; i++)
\r
2698 *(--dp) = lo_filler;
\r
2699 *(--dp) = *(--sp);
\r
2701 *(--dp) = lo_filler;
\r
2702 row_info->channels = 2;
\r
2703 row_info->pixel_depth = 16;
\r
2704 row_info->rowbytes = row_width * 2;
\r
2709 /* This changes the data from G to XG */
\r
2710 png_bytep sp = row + (size_t)row_width;
\r
2711 png_bytep dp = sp + (size_t)row_width;
\r
2712 for (i = 0; i < row_width; i++)
\r
2714 *(--dp) = *(--sp);
\r
2715 *(--dp) = lo_filler;
\r
2717 row_info->channels = 2;
\r
2718 row_info->pixel_depth = 16;
\r
2719 row_info->rowbytes = row_width * 2;
\r
2723 #ifdef PNG_READ_16BIT_SUPPORTED
\r
2724 else if (row_info->bit_depth == 16)
\r
2726 if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
\r
2728 /* This changes the data from GG to GGXX */
\r
2729 png_bytep sp = row + (size_t)row_width * 2;
\r
2730 png_bytep dp = sp + (size_t)row_width * 2;
\r
2731 for (i = 1; i < row_width; i++)
\r
2733 *(--dp) = lo_filler;
\r
2734 *(--dp) = hi_filler;
\r
2735 *(--dp) = *(--sp);
\r
2736 *(--dp) = *(--sp);
\r
2738 *(--dp) = lo_filler;
\r
2739 *(--dp) = hi_filler;
\r
2740 row_info->channels = 2;
\r
2741 row_info->pixel_depth = 32;
\r
2742 row_info->rowbytes = row_width * 4;
\r
2747 /* This changes the data from GG to XXGG */
\r
2748 png_bytep sp = row + (size_t)row_width * 2;
\r
2749 png_bytep dp = sp + (size_t)row_width * 2;
\r
2750 for (i = 0; i < row_width; i++)
\r
2752 *(--dp) = *(--sp);
\r
2753 *(--dp) = *(--sp);
\r
2754 *(--dp) = lo_filler;
\r
2755 *(--dp) = hi_filler;
\r
2757 row_info->channels = 2;
\r
2758 row_info->pixel_depth = 32;
\r
2759 row_info->rowbytes = row_width * 4;
\r
2763 } /* COLOR_TYPE == GRAY */
\r
2764 else if (row_info->color_type == PNG_COLOR_TYPE_RGB)
\r
2766 if (row_info->bit_depth == 8)
\r
2768 if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
\r
2770 /* This changes the data from RGB to RGBX */
\r
2771 png_bytep sp = row + (size_t)row_width * 3;
\r
2772 png_bytep dp = sp + (size_t)row_width;
\r
2773 for (i = 1; i < row_width; i++)
\r
2775 *(--dp) = lo_filler;
\r
2776 *(--dp) = *(--sp);
\r
2777 *(--dp) = *(--sp);
\r
2778 *(--dp) = *(--sp);
\r
2780 *(--dp) = lo_filler;
\r
2781 row_info->channels = 4;
\r
2782 row_info->pixel_depth = 32;
\r
2783 row_info->rowbytes = row_width * 4;
\r
2788 /* This changes the data from RGB to XRGB */
\r
2789 png_bytep sp = row + (size_t)row_width * 3;
\r
2790 png_bytep dp = sp + (size_t)row_width;
\r
2791 for (i = 0; i < row_width; i++)
\r
2793 *(--dp) = *(--sp);
\r
2794 *(--dp) = *(--sp);
\r
2795 *(--dp) = *(--sp);
\r
2796 *(--dp) = lo_filler;
\r
2798 row_info->channels = 4;
\r
2799 row_info->pixel_depth = 32;
\r
2800 row_info->rowbytes = row_width * 4;
\r
2804 #ifdef PNG_READ_16BIT_SUPPORTED
\r
2805 else if (row_info->bit_depth == 16)
\r
2807 if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
\r
2809 /* This changes the data from RRGGBB to RRGGBBXX */
\r
2810 png_bytep sp = row + (size_t)row_width * 6;
\r
2811 png_bytep dp = sp + (size_t)row_width * 2;
\r
2812 for (i = 1; i < row_width; i++)
\r
2814 *(--dp) = lo_filler;
\r
2815 *(--dp) = hi_filler;
\r
2816 *(--dp) = *(--sp);
\r
2817 *(--dp) = *(--sp);
\r
2818 *(--dp) = *(--sp);
\r
2819 *(--dp) = *(--sp);
\r
2820 *(--dp) = *(--sp);
\r
2821 *(--dp) = *(--sp);
\r
2823 *(--dp) = lo_filler;
\r
2824 *(--dp) = hi_filler;
\r
2825 row_info->channels = 4;
\r
2826 row_info->pixel_depth = 64;
\r
2827 row_info->rowbytes = row_width * 8;
\r
2832 /* This changes the data from RRGGBB to XXRRGGBB */
\r
2833 png_bytep sp = row + (size_t)row_width * 6;
\r
2834 png_bytep dp = sp + (size_t)row_width * 2;
\r
2835 for (i = 0; i < row_width; i++)
\r
2837 *(--dp) = *(--sp);
\r
2838 *(--dp) = *(--sp);
\r
2839 *(--dp) = *(--sp);
\r
2840 *(--dp) = *(--sp);
\r
2841 *(--dp) = *(--sp);
\r
2842 *(--dp) = *(--sp);
\r
2843 *(--dp) = lo_filler;
\r
2844 *(--dp) = hi_filler;
\r
2847 row_info->channels = 4;
\r
2848 row_info->pixel_depth = 64;
\r
2849 row_info->rowbytes = row_width * 8;
\r
2853 } /* COLOR_TYPE == RGB */
\r
2857 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
\r
2858 /* Expand grayscale files to RGB, with or without alpha */
\r
2860 png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
\r
2863 png_uint_32 row_width = row_info->width;
\r
2865 png_debug(1, "in png_do_gray_to_rgb");
\r
2867 if (row_info->bit_depth >= 8 &&
\r
2868 (row_info->color_type & PNG_COLOR_MASK_COLOR) == 0)
\r
2870 if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
\r
2872 if (row_info->bit_depth == 8)
\r
2874 /* This changes G to RGB */
\r
2875 png_bytep sp = row + (size_t)row_width - 1;
\r
2876 png_bytep dp = sp + (size_t)row_width * 2;
\r
2877 for (i = 0; i < row_width; i++)
\r
2881 *(dp--) = *(sp--);
\r
2887 /* This changes GG to RRGGBB */
\r
2888 png_bytep sp = row + (size_t)row_width * 2 - 1;
\r
2889 png_bytep dp = sp + (size_t)row_width * 4;
\r
2890 for (i = 0; i < row_width; i++)
\r
2893 *(dp--) = *(sp - 1);
\r
2895 *(dp--) = *(sp - 1);
\r
2896 *(dp--) = *(sp--);
\r
2897 *(dp--) = *(sp--);
\r
2902 else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
\r
2904 if (row_info->bit_depth == 8)
\r
2906 /* This changes GA to RGBA */
\r
2907 png_bytep sp = row + (size_t)row_width * 2 - 1;
\r
2908 png_bytep dp = sp + (size_t)row_width * 2;
\r
2909 for (i = 0; i < row_width; i++)
\r
2911 *(dp--) = *(sp--);
\r
2914 *(dp--) = *(sp--);
\r
2920 /* This changes GGAA to RRGGBBAA */
\r
2921 png_bytep sp = row + (size_t)row_width * 4 - 1;
\r
2922 png_bytep dp = sp + (size_t)row_width * 4;
\r
2923 for (i = 0; i < row_width; i++)
\r
2925 *(dp--) = *(sp--);
\r
2926 *(dp--) = *(sp--);
\r
2928 *(dp--) = *(sp - 1);
\r
2930 *(dp--) = *(sp - 1);
\r
2931 *(dp--) = *(sp--);
\r
2932 *(dp--) = *(sp--);
\r
2936 row_info->channels = (png_byte)(row_info->channels + 2);
\r
2937 row_info->color_type |= PNG_COLOR_MASK_COLOR;
\r
2938 row_info->pixel_depth = (png_byte)(row_info->channels *
\r
2939 row_info->bit_depth);
\r
2940 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
\r
2945 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
\r
2946 /* Reduce RGB files to grayscale, with or without alpha
\r
2947 * using the equation given in Poynton's ColorFAQ of 1998-01-04 at
\r
2948 * <http://www.inforamp.net/~poynton/> (THIS LINK IS DEAD June 2008 but
\r
2949 * versions dated 1998 through November 2002 have been archived at
\r
2950 * https://web.archive.org/web/20000816232553/www.inforamp.net/
\r
2951 * ~poynton/notes/colour_and_gamma/ColorFAQ.txt )
\r
2952 * Charles Poynton poynton at poynton.com
\r
2954 * Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
\r
2956 * which can be expressed with integers as
\r
2958 * Y = (6969 * R + 23434 * G + 2365 * B)/32768
\r
2960 * Poynton's current link (as of January 2003 through July 2011):
\r
2961 * <http://www.poynton.com/notes/colour_and_gamma/>
\r
2962 * has changed the numbers slightly:
\r
2964 * Y = 0.2126*R + 0.7152*G + 0.0722*B
\r
2966 * which can be expressed with integers as
\r
2968 * Y = (6966 * R + 23436 * G + 2366 * B)/32768
\r
2970 * Historically, however, libpng uses numbers derived from the ITU-R Rec 709
\r
2971 * end point chromaticities and the D65 white point. Depending on the
\r
2972 * precision used for the D65 white point this produces a variety of different
\r
2973 * numbers, however if the four decimal place value used in ITU-R Rec 709 is
\r
2974 * used (0.3127,0.3290) the Y calculation would be:
\r
2976 * Y = (6968 * R + 23435 * G + 2366 * B)/32768
\r
2978 * While this is correct the rounding results in an overflow for white, because
\r
2979 * the sum of the rounded coefficients is 32769, not 32768. Consequently
\r
2980 * libpng uses, instead, the closest non-overflowing approximation:
\r
2982 * Y = (6968 * R + 23434 * G + 2366 * B)/32768
\r
2984 * Starting with libpng-1.5.5, if the image being converted has a cHRM chunk
\r
2985 * (including an sRGB chunk) then the chromaticities are used to calculate the
\r
2986 * coefficients. See the chunk handling in pngrutil.c for more information.
\r
2988 * In all cases the calculation is to be done in a linear colorspace. If no
\r
2989 * gamma information is available to correct the encoding of the original RGB
\r
2990 * values this results in an implicit assumption that the original PNG RGB
\r
2991 * values were linear.
\r
2993 * Other integer coefficients can be used via png_set_rgb_to_gray(). Because
\r
2994 * the API takes just red and green coefficients the blue coefficient is
\r
2995 * calculated to make the sum 32768. This will result in different rounding
\r
2996 * to that used above.
\r
2999 png_do_rgb_to_gray(png_structrp png_ptr, png_row_infop row_info, png_bytep row)
\r
3001 int rgb_error = 0;
\r
3003 png_debug(1, "in png_do_rgb_to_gray");
\r
3005 if ((row_info->color_type & PNG_COLOR_MASK_PALETTE) == 0 &&
\r
3006 (row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
\r
3008 png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff;
\r
3009 png_uint_32 gc = png_ptr->rgb_to_gray_green_coeff;
\r
3010 png_uint_32 bc = 32768 - rc - gc;
\r
3011 png_uint_32 row_width = row_info->width;
\r
3012 int have_alpha = (row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0;
\r
3014 if (row_info->bit_depth == 8)
\r
3016 #ifdef PNG_READ_GAMMA_SUPPORTED
\r
3017 /* Notice that gamma to/from 1 are not necessarily inverses (if
\r
3018 * there is an overall gamma correction). Prior to 1.5.5 this code
\r
3019 * checked the linearized values for equality; this doesn't match
\r
3020 * the documentation, the original values must be checked.
\r
3022 if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL)
\r
3024 png_bytep sp = row;
\r
3025 png_bytep dp = row;
\r
3028 for (i = 0; i < row_width; i++)
\r
3030 png_byte red = *(sp++);
\r
3031 png_byte green = *(sp++);
\r
3032 png_byte blue = *(sp++);
\r
3034 if (red != green || red != blue)
\r
3036 red = png_ptr->gamma_to_1[red];
\r
3037 green = png_ptr->gamma_to_1[green];
\r
3038 blue = png_ptr->gamma_to_1[blue];
\r
3041 *(dp++) = png_ptr->gamma_from_1[
\r
3042 (rc*red + gc*green + bc*blue + 16384)>>15];
\r
3047 /* If there is no overall correction the table will not be
\r
3050 if (png_ptr->gamma_table != NULL)
\r
3051 red = png_ptr->gamma_table[red];
\r
3056 if (have_alpha != 0)
\r
3057 *(dp++) = *(sp++);
\r
3063 png_bytep sp = row;
\r
3064 png_bytep dp = row;
\r
3067 for (i = 0; i < row_width; i++)
\r
3069 png_byte red = *(sp++);
\r
3070 png_byte green = *(sp++);
\r
3071 png_byte blue = *(sp++);
\r
3073 if (red != green || red != blue)
\r
3076 /* NOTE: this is the historical approach which simply
\r
3077 * truncates the results.
\r
3079 *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15);
\r
3085 if (have_alpha != 0)
\r
3086 *(dp++) = *(sp++);
\r
3091 else /* RGB bit_depth == 16 */
\r
3093 #ifdef PNG_READ_GAMMA_SUPPORTED
\r
3094 if (png_ptr->gamma_16_to_1 != NULL && png_ptr->gamma_16_from_1 != NULL)
\r
3096 png_bytep sp = row;
\r
3097 png_bytep dp = row;
\r
3100 for (i = 0; i < row_width; i++)
\r
3102 png_uint_16 red, green, blue, w;
\r
3105 hi=*(sp)++; lo=*(sp)++; red = (png_uint_16)((hi << 8) | (lo));
\r
3106 hi=*(sp)++; lo=*(sp)++; green = (png_uint_16)((hi << 8) | (lo));
\r
3107 hi=*(sp)++; lo=*(sp)++; blue = (png_uint_16)((hi << 8) | (lo));
\r
3109 if (red == green && red == blue)
\r
3111 if (png_ptr->gamma_16_table != NULL)
\r
3112 w = png_ptr->gamma_16_table[(red & 0xff)
\r
3113 >> png_ptr->gamma_shift][red >> 8];
\r
3121 png_uint_16 red_1 = png_ptr->gamma_16_to_1[(red & 0xff)
\r
3122 >> png_ptr->gamma_shift][red>>8];
\r
3123 png_uint_16 green_1 =
\r
3124 png_ptr->gamma_16_to_1[(green & 0xff) >>
\r
3125 png_ptr->gamma_shift][green>>8];
\r
3126 png_uint_16 blue_1 = png_ptr->gamma_16_to_1[(blue & 0xff)
\r
3127 >> png_ptr->gamma_shift][blue>>8];
\r
3128 png_uint_16 gray16 = (png_uint_16)((rc*red_1 + gc*green_1
\r
3129 + bc*blue_1 + 16384)>>15);
\r
3130 w = png_ptr->gamma_16_from_1[(gray16 & 0xff) >>
\r
3131 png_ptr->gamma_shift][gray16 >> 8];
\r
3135 *(dp++) = (png_byte)((w>>8) & 0xff);
\r
3136 *(dp++) = (png_byte)(w & 0xff);
\r
3138 if (have_alpha != 0)
\r
3140 *(dp++) = *(sp++);
\r
3141 *(dp++) = *(sp++);
\r
3148 png_bytep sp = row;
\r
3149 png_bytep dp = row;
\r
3152 for (i = 0; i < row_width; i++)
\r
3154 png_uint_16 red, green, blue, gray16;
\r
3157 hi=*(sp)++; lo=*(sp)++; red = (png_uint_16)((hi << 8) | (lo));
\r
3158 hi=*(sp)++; lo=*(sp)++; green = (png_uint_16)((hi << 8) | (lo));
\r
3159 hi=*(sp)++; lo=*(sp)++; blue = (png_uint_16)((hi << 8) | (lo));
\r
3161 if (red != green || red != blue)
\r
3164 /* From 1.5.5 in the 16-bit case do the accurate conversion even
\r
3165 * in the 'fast' case - this is because this is where the code
\r
3166 * ends up when handling linear 16-bit data.
\r
3168 gray16 = (png_uint_16)((rc*red + gc*green + bc*blue + 16384) >>
\r
3170 *(dp++) = (png_byte)((gray16 >> 8) & 0xff);
\r
3171 *(dp++) = (png_byte)(gray16 & 0xff);
\r
3173 if (have_alpha != 0)
\r
3175 *(dp++) = *(sp++);
\r
3176 *(dp++) = *(sp++);
\r
3182 row_info->channels = (png_byte)(row_info->channels - 2);
\r
3183 row_info->color_type = (png_byte)(row_info->color_type &
\r
3184 ~PNG_COLOR_MASK_COLOR);
\r
3185 row_info->pixel_depth = (png_byte)(row_info->channels *
\r
3186 row_info->bit_depth);
\r
3187 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
\r
3193 #if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
\r
3194 defined(PNG_READ_ALPHA_MODE_SUPPORTED)
\r
3195 /* Replace any alpha or transparency with the supplied background color.
\r
3196 * "background" is already in the screen gamma, while "background_1" is
\r
3197 * at a gamma of 1.0. Paletted files have already been taken care of.
\r
3200 png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
\r
3202 #ifdef PNG_READ_GAMMA_SUPPORTED
\r
3203 png_const_bytep gamma_table = png_ptr->gamma_table;
\r
3204 png_const_bytep gamma_from_1 = png_ptr->gamma_from_1;
\r
3205 png_const_bytep gamma_to_1 = png_ptr->gamma_to_1;
\r
3206 png_const_uint_16pp gamma_16 = png_ptr->gamma_16_table;
\r
3207 png_const_uint_16pp gamma_16_from_1 = png_ptr->gamma_16_from_1;
\r
3208 png_const_uint_16pp gamma_16_to_1 = png_ptr->gamma_16_to_1;
\r
3209 int gamma_shift = png_ptr->gamma_shift;
\r
3210 int optimize = (png_ptr->flags & PNG_FLAG_OPTIMIZE_ALPHA) != 0;
\r
3215 png_uint_32 row_width = row_info->width;
\r
3218 png_debug(1, "in png_do_compose");
\r
3220 switch (row_info->color_type)
\r
3222 case PNG_COLOR_TYPE_GRAY:
\r
3224 switch (row_info->bit_depth)
\r
3230 for (i = 0; i < row_width; i++)
\r
3232 if ((png_uint_16)((*sp >> shift) & 0x01)
\r
3233 == png_ptr->trans_color.gray)
\r
3235 unsigned int tmp = *sp & (0x7f7f >> (7 - shift));
\r
3237 (unsigned int)(png_ptr->background.gray << shift);
\r
3238 *sp = (png_byte)(tmp & 0xff);
\r
3255 #ifdef PNG_READ_GAMMA_SUPPORTED
\r
3256 if (gamma_table != NULL)
\r
3260 for (i = 0; i < row_width; i++)
\r
3262 if ((png_uint_16)((*sp >> shift) & 0x03)
\r
3263 == png_ptr->trans_color.gray)
\r
3265 unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
\r
3267 (unsigned int)png_ptr->background.gray << shift;
\r
3268 *sp = (png_byte)(tmp & 0xff);
\r
3273 unsigned int p = (*sp >> shift) & 0x03;
\r
3274 unsigned int g = (gamma_table [p | (p << 2) |
\r
3275 (p << 4) | (p << 6)] >> 6) & 0x03;
\r
3276 unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
\r
3277 tmp |= (unsigned int)(g << shift);
\r
3278 *sp = (png_byte)(tmp & 0xff);
\r
3297 for (i = 0; i < row_width; i++)
\r
3299 if ((png_uint_16)((*sp >> shift) & 0x03)
\r
3300 == png_ptr->trans_color.gray)
\r
3302 unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
\r
3304 (unsigned int)png_ptr->background.gray << shift;
\r
3305 *sp = (png_byte)(tmp & 0xff);
\r
3323 #ifdef PNG_READ_GAMMA_SUPPORTED
\r
3324 if (gamma_table != NULL)
\r
3328 for (i = 0; i < row_width; i++)
\r
3330 if ((png_uint_16)((*sp >> shift) & 0x0f)
\r
3331 == png_ptr->trans_color.gray)
\r
3333 unsigned int tmp = *sp & (0x0f0f >> (4 - shift));
\r
3335 (unsigned int)(png_ptr->background.gray << shift);
\r
3336 *sp = (png_byte)(tmp & 0xff);
\r
3341 unsigned int p = (*sp >> shift) & 0x0f;
\r
3342 unsigned int g = (gamma_table[p | (p << 4)] >> 4) &
\r
3344 unsigned int tmp = *sp & (0x0f0f >> (4 - shift));
\r
3345 tmp |= (unsigned int)(g << shift);
\r
3346 *sp = (png_byte)(tmp & 0xff);
\r
3365 for (i = 0; i < row_width; i++)
\r
3367 if ((png_uint_16)((*sp >> shift) & 0x0f)
\r
3368 == png_ptr->trans_color.gray)
\r
3370 unsigned int tmp = *sp & (0x0f0f >> (4 - shift));
\r
3372 (unsigned int)(png_ptr->background.gray << shift);
\r
3373 *sp = (png_byte)(tmp & 0xff);
\r
3391 #ifdef PNG_READ_GAMMA_SUPPORTED
\r
3392 if (gamma_table != NULL)
\r
3395 for (i = 0; i < row_width; i++, sp++)
\r
3397 if (*sp == png_ptr->trans_color.gray)
\r
3398 *sp = (png_byte)png_ptr->background.gray;
\r
3401 *sp = gamma_table[*sp];
\r
3408 for (i = 0; i < row_width; i++, sp++)
\r
3410 if (*sp == png_ptr->trans_color.gray)
\r
3411 *sp = (png_byte)png_ptr->background.gray;
\r
3419 #ifdef PNG_READ_GAMMA_SUPPORTED
\r
3420 if (gamma_16 != NULL)
\r
3423 for (i = 0; i < row_width; i++, sp += 2)
\r
3427 v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
\r
3429 if (v == png_ptr->trans_color.gray)
\r
3431 /* Background is already in screen gamma */
\r
3432 *sp = (png_byte)((png_ptr->background.gray >> 8)
\r
3434 *(sp + 1) = (png_byte)(png_ptr->background.gray
\r
3440 v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
\r
3441 *sp = (png_byte)((v >> 8) & 0xff);
\r
3442 *(sp + 1) = (png_byte)(v & 0xff);
\r
3450 for (i = 0; i < row_width; i++, sp += 2)
\r
3454 v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
\r
3456 if (v == png_ptr->trans_color.gray)
\r
3458 *sp = (png_byte)((png_ptr->background.gray >> 8)
\r
3460 *(sp + 1) = (png_byte)(png_ptr->background.gray
\r
3474 case PNG_COLOR_TYPE_RGB:
\r
3476 if (row_info->bit_depth == 8)
\r
3478 #ifdef PNG_READ_GAMMA_SUPPORTED
\r
3479 if (gamma_table != NULL)
\r
3482 for (i = 0; i < row_width; i++, sp += 3)
\r
3484 if (*sp == png_ptr->trans_color.red &&
\r
3485 *(sp + 1) == png_ptr->trans_color.green &&
\r
3486 *(sp + 2) == png_ptr->trans_color.blue)
\r
3488 *sp = (png_byte)png_ptr->background.red;
\r
3489 *(sp + 1) = (png_byte)png_ptr->background.green;
\r
3490 *(sp + 2) = (png_byte)png_ptr->background.blue;
\r
3495 *sp = gamma_table[*sp];
\r
3496 *(sp + 1) = gamma_table[*(sp + 1)];
\r
3497 *(sp + 2) = gamma_table[*(sp + 2)];
\r
3505 for (i = 0; i < row_width; i++, sp += 3)
\r
3507 if (*sp == png_ptr->trans_color.red &&
\r
3508 *(sp + 1) == png_ptr->trans_color.green &&
\r
3509 *(sp + 2) == png_ptr->trans_color.blue)
\r
3511 *sp = (png_byte)png_ptr->background.red;
\r
3512 *(sp + 1) = (png_byte)png_ptr->background.green;
\r
3513 *(sp + 2) = (png_byte)png_ptr->background.blue;
\r
3518 else /* if (row_info->bit_depth == 16) */
\r
3520 #ifdef PNG_READ_GAMMA_SUPPORTED
\r
3521 if (gamma_16 != NULL)
\r
3524 for (i = 0; i < row_width; i++, sp += 6)
\r
3526 png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
\r
3528 png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
\r
3531 png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
\r
3534 if (r == png_ptr->trans_color.red &&
\r
3535 g == png_ptr->trans_color.green &&
\r
3536 b == png_ptr->trans_color.blue)
\r
3538 /* Background is already in screen gamma */
\r
3539 *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
\r
3540 *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
\r
3541 *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
\r
3543 *(sp + 3) = (png_byte)(png_ptr->background.green
\r
3545 *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
\r
3547 *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
\r
3552 png_uint_16 v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
\r
3553 *sp = (png_byte)((v >> 8) & 0xff);
\r
3554 *(sp + 1) = (png_byte)(v & 0xff);
\r
3556 v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
\r
3557 *(sp + 2) = (png_byte)((v >> 8) & 0xff);
\r
3558 *(sp + 3) = (png_byte)(v & 0xff);
\r
3560 v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
\r
3561 *(sp + 4) = (png_byte)((v >> 8) & 0xff);
\r
3562 *(sp + 5) = (png_byte)(v & 0xff);
\r
3571 for (i = 0; i < row_width; i++, sp += 6)
\r
3573 png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
\r
3575 png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
\r
3578 png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
\r
3581 if (r == png_ptr->trans_color.red &&
\r
3582 g == png_ptr->trans_color.green &&
\r
3583 b == png_ptr->trans_color.blue)
\r
3585 *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
\r
3586 *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
\r
3587 *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
\r
3589 *(sp + 3) = (png_byte)(png_ptr->background.green
\r
3591 *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
\r
3593 *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
\r
3601 case PNG_COLOR_TYPE_GRAY_ALPHA:
\r
3603 if (row_info->bit_depth == 8)
\r
3605 #ifdef PNG_READ_GAMMA_SUPPORTED
\r
3606 if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
\r
3607 gamma_table != NULL)
\r
3610 for (i = 0; i < row_width; i++, sp += 2)
\r
3612 png_uint_16 a = *(sp + 1);
\r
3615 *sp = gamma_table[*sp];
\r
3619 /* Background is already in screen gamma */
\r
3620 *sp = (png_byte)png_ptr->background.gray;
\r
3627 v = gamma_to_1[*sp];
\r
3628 png_composite(w, v, a, png_ptr->background_1.gray);
\r
3629 if (optimize == 0)
\r
3630 w = gamma_from_1[w];
\r
3639 for (i = 0; i < row_width; i++, sp += 2)
\r
3641 png_byte a = *(sp + 1);
\r
3644 *sp = (png_byte)png_ptr->background.gray;
\r
3646 else if (a < 0xff)
\r
3647 png_composite(*sp, *sp, a, png_ptr->background.gray);
\r
3651 else /* if (png_ptr->bit_depth == 16) */
\r
3653 #ifdef PNG_READ_GAMMA_SUPPORTED
\r
3654 if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
\r
3655 gamma_16_to_1 != NULL)
\r
3658 for (i = 0; i < row_width; i++, sp += 4)
\r
3660 png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8)
\r
3663 if (a == (png_uint_16)0xffff)
\r
3667 v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
\r
3668 *sp = (png_byte)((v >> 8) & 0xff);
\r
3669 *(sp + 1) = (png_byte)(v & 0xff);
\r
3674 /* Background is already in screen gamma */
\r
3675 *sp = (png_byte)((png_ptr->background.gray >> 8)
\r
3677 *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
\r
3682 png_uint_16 g, v, w;
\r
3684 g = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
\r
3685 png_composite_16(v, g, a, png_ptr->background_1.gray);
\r
3686 if (optimize != 0)
\r
3689 w = gamma_16_from_1[(v & 0xff) >>
\r
3690 gamma_shift][v >> 8];
\r
3691 *sp = (png_byte)((w >> 8) & 0xff);
\r
3692 *(sp + 1) = (png_byte)(w & 0xff);
\r
3700 for (i = 0; i < row_width; i++, sp += 4)
\r
3702 png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8)
\r
3707 *sp = (png_byte)((png_ptr->background.gray >> 8)
\r
3709 *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
\r
3712 else if (a < 0xffff)
\r
3716 g = (png_uint_16)(((*sp) << 8) + *(sp + 1));
\r
3717 png_composite_16(v, g, a, png_ptr->background.gray);
\r
3718 *sp = (png_byte)((v >> 8) & 0xff);
\r
3719 *(sp + 1) = (png_byte)(v & 0xff);
\r
3727 case PNG_COLOR_TYPE_RGB_ALPHA:
\r
3729 if (row_info->bit_depth == 8)
\r
3731 #ifdef PNG_READ_GAMMA_SUPPORTED
\r
3732 if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
\r
3733 gamma_table != NULL)
\r
3736 for (i = 0; i < row_width; i++, sp += 4)
\r
3738 png_byte a = *(sp + 3);
\r
3742 *sp = gamma_table[*sp];
\r
3743 *(sp + 1) = gamma_table[*(sp + 1)];
\r
3744 *(sp + 2) = gamma_table[*(sp + 2)];
\r
3749 /* Background is already in screen gamma */
\r
3750 *sp = (png_byte)png_ptr->background.red;
\r
3751 *(sp + 1) = (png_byte)png_ptr->background.green;
\r
3752 *(sp + 2) = (png_byte)png_ptr->background.blue;
\r
3759 v = gamma_to_1[*sp];
\r
3760 png_composite(w, v, a, png_ptr->background_1.red);
\r
3761 if (optimize == 0) w = gamma_from_1[w];
\r
3764 v = gamma_to_1[*(sp + 1)];
\r
3765 png_composite(w, v, a, png_ptr->background_1.green);
\r
3766 if (optimize == 0) w = gamma_from_1[w];
\r
3769 v = gamma_to_1[*(sp + 2)];
\r
3770 png_composite(w, v, a, png_ptr->background_1.blue);
\r
3771 if (optimize == 0) w = gamma_from_1[w];
\r
3780 for (i = 0; i < row_width; i++, sp += 4)
\r
3782 png_byte a = *(sp + 3);
\r
3786 *sp = (png_byte)png_ptr->background.red;
\r
3787 *(sp + 1) = (png_byte)png_ptr->background.green;
\r
3788 *(sp + 2) = (png_byte)png_ptr->background.blue;
\r
3791 else if (a < 0xff)
\r
3793 png_composite(*sp, *sp, a, png_ptr->background.red);
\r
3795 png_composite(*(sp + 1), *(sp + 1), a,
\r
3796 png_ptr->background.green);
\r
3798 png_composite(*(sp + 2), *(sp + 2), a,
\r
3799 png_ptr->background.blue);
\r
3804 else /* if (row_info->bit_depth == 16) */
\r
3806 #ifdef PNG_READ_GAMMA_SUPPORTED
\r
3807 if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
\r
3808 gamma_16_to_1 != NULL)
\r
3811 for (i = 0; i < row_width; i++, sp += 8)
\r
3813 png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
\r
3814 << 8) + (png_uint_16)(*(sp + 7)));
\r
3816 if (a == (png_uint_16)0xffff)
\r
3820 v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
\r
3821 *sp = (png_byte)((v >> 8) & 0xff);
\r
3822 *(sp + 1) = (png_byte)(v & 0xff);
\r
3824 v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
\r
3825 *(sp + 2) = (png_byte)((v >> 8) & 0xff);
\r
3826 *(sp + 3) = (png_byte)(v & 0xff);
\r
3828 v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
\r
3829 *(sp + 4) = (png_byte)((v >> 8) & 0xff);
\r
3830 *(sp + 5) = (png_byte)(v & 0xff);
\r
3835 /* Background is already in screen gamma */
\r
3836 *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
\r
3837 *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
\r
3838 *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
\r
3840 *(sp + 3) = (png_byte)(png_ptr->background.green
\r
3842 *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
\r
3844 *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
\r
3851 v = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
\r
3852 png_composite_16(w, v, a, png_ptr->background_1.red);
\r
3853 if (optimize == 0)
\r
3854 w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
\r
3856 *sp = (png_byte)((w >> 8) & 0xff);
\r
3857 *(sp + 1) = (png_byte)(w & 0xff);
\r
3859 v = gamma_16_to_1[*(sp + 3) >> gamma_shift][*(sp + 2)];
\r
3860 png_composite_16(w, v, a, png_ptr->background_1.green);
\r
3861 if (optimize == 0)
\r
3862 w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
\r
3865 *(sp + 2) = (png_byte)((w >> 8) & 0xff);
\r
3866 *(sp + 3) = (png_byte)(w & 0xff);
\r
3868 v = gamma_16_to_1[*(sp + 5) >> gamma_shift][*(sp + 4)];
\r
3869 png_composite_16(w, v, a, png_ptr->background_1.blue);
\r
3870 if (optimize == 0)
\r
3871 w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
\r
3874 *(sp + 4) = (png_byte)((w >> 8) & 0xff);
\r
3875 *(sp + 5) = (png_byte)(w & 0xff);
\r
3884 for (i = 0; i < row_width; i++, sp += 8)
\r
3886 png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
\r
3887 << 8) + (png_uint_16)(*(sp + 7)));
\r
3891 *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
\r
3892 *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
\r
3893 *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
\r
3895 *(sp + 3) = (png_byte)(png_ptr->background.green
\r
3897 *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
\r
3899 *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
\r
3902 else if (a < 0xffff)
\r
3906 png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
\r
3907 png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
\r
3909 png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
\r
3912 png_composite_16(v, r, a, png_ptr->background.red);
\r
3913 *sp = (png_byte)((v >> 8) & 0xff);
\r
3914 *(sp + 1) = (png_byte)(v & 0xff);
\r
3916 png_composite_16(v, g, a, png_ptr->background.green);
\r
3917 *(sp + 2) = (png_byte)((v >> 8) & 0xff);
\r
3918 *(sp + 3) = (png_byte)(v & 0xff);
\r
3920 png_composite_16(v, b, a, png_ptr->background.blue);
\r
3921 *(sp + 4) = (png_byte)((v >> 8) & 0xff);
\r
3922 *(sp + 5) = (png_byte)(v & 0xff);
\r
3934 #endif /* READ_BACKGROUND || READ_ALPHA_MODE */
\r
3936 #ifdef PNG_READ_GAMMA_SUPPORTED
\r
3937 /* Gamma correct the image, avoiding the alpha channel. Make sure
\r
3938 * you do this after you deal with the transparency issue on grayscale
\r
3939 * or RGB images. If your bit depth is 8, use gamma_table, if it
\r
3940 * is 16, use gamma_16_table and gamma_shift. Build these with
\r
3941 * build_gamma_table().
\r
3944 png_do_gamma(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
\r
3946 png_const_bytep gamma_table = png_ptr->gamma_table;
\r
3947 png_const_uint_16pp gamma_16_table = png_ptr->gamma_16_table;
\r
3948 int gamma_shift = png_ptr->gamma_shift;
\r
3952 png_uint_32 row_width=row_info->width;
\r
3954 png_debug(1, "in png_do_gamma");
\r
3956 if (((row_info->bit_depth <= 8 && gamma_table != NULL) ||
\r
3957 (row_info->bit_depth == 16 && gamma_16_table != NULL)))
\r
3959 switch (row_info->color_type)
\r
3961 case PNG_COLOR_TYPE_RGB:
\r
3963 if (row_info->bit_depth == 8)
\r
3966 for (i = 0; i < row_width; i++)
\r
3968 *sp = gamma_table[*sp];
\r
3970 *sp = gamma_table[*sp];
\r
3972 *sp = gamma_table[*sp];
\r
3977 else /* if (row_info->bit_depth == 16) */
\r
3980 for (i = 0; i < row_width; i++)
\r
3984 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
\r
3985 *sp = (png_byte)((v >> 8) & 0xff);
\r
3986 *(sp + 1) = (png_byte)(v & 0xff);
\r
3989 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
\r
3990 *sp = (png_byte)((v >> 8) & 0xff);
\r
3991 *(sp + 1) = (png_byte)(v & 0xff);
\r
3994 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
\r
3995 *sp = (png_byte)((v >> 8) & 0xff);
\r
3996 *(sp + 1) = (png_byte)(v & 0xff);
\r
4003 case PNG_COLOR_TYPE_RGB_ALPHA:
\r
4005 if (row_info->bit_depth == 8)
\r
4008 for (i = 0; i < row_width; i++)
\r
4010 *sp = gamma_table[*sp];
\r
4013 *sp = gamma_table[*sp];
\r
4016 *sp = gamma_table[*sp];
\r
4023 else /* if (row_info->bit_depth == 16) */
\r
4026 for (i = 0; i < row_width; i++)
\r
4028 png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
\r
4029 *sp = (png_byte)((v >> 8) & 0xff);
\r
4030 *(sp + 1) = (png_byte)(v & 0xff);
\r
4033 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
\r
4034 *sp = (png_byte)((v >> 8) & 0xff);
\r
4035 *(sp + 1) = (png_byte)(v & 0xff);
\r
4038 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
\r
4039 *sp = (png_byte)((v >> 8) & 0xff);
\r
4040 *(sp + 1) = (png_byte)(v & 0xff);
\r
4047 case PNG_COLOR_TYPE_GRAY_ALPHA:
\r
4049 if (row_info->bit_depth == 8)
\r
4052 for (i = 0; i < row_width; i++)
\r
4054 *sp = gamma_table[*sp];
\r
4059 else /* if (row_info->bit_depth == 16) */
\r
4062 for (i = 0; i < row_width; i++)
\r
4064 png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
\r
4065 *sp = (png_byte)((v >> 8) & 0xff);
\r
4066 *(sp + 1) = (png_byte)(v & 0xff);
\r
4073 case PNG_COLOR_TYPE_GRAY:
\r
4075 if (row_info->bit_depth == 2)
\r
4078 for (i = 0; i < row_width; i += 4)
\r
4080 int a = *sp & 0xc0;
\r
4081 int b = *sp & 0x30;
\r
4082 int c = *sp & 0x0c;
\r
4083 int d = *sp & 0x03;
\r
4086 ((((int)gamma_table[a|(a>>2)|(a>>4)|(a>>6)]) ) & 0xc0)|
\r
4087 ((((int)gamma_table[(b<<2)|b|(b>>2)|(b>>4)])>>2) & 0x30)|
\r
4088 ((((int)gamma_table[(c<<4)|(c<<2)|c|(c>>2)])>>4) & 0x0c)|
\r
4089 ((((int)gamma_table[(d<<6)|(d<<4)|(d<<2)|d])>>6) ));
\r
4094 if (row_info->bit_depth == 4)
\r
4097 for (i = 0; i < row_width; i += 2)
\r
4099 int msb = *sp & 0xf0;
\r
4100 int lsb = *sp & 0x0f;
\r
4102 *sp = (png_byte)((((int)gamma_table[msb | (msb >> 4)]) & 0xf0)
\r
4103 | (((int)gamma_table[(lsb << 4) | lsb]) >> 4));
\r
4108 else if (row_info->bit_depth == 8)
\r
4111 for (i = 0; i < row_width; i++)
\r
4113 *sp = gamma_table[*sp];
\r
4118 else if (row_info->bit_depth == 16)
\r
4121 for (i = 0; i < row_width; i++)
\r
4123 png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
\r
4124 *sp = (png_byte)((v >> 8) & 0xff);
\r
4125 *(sp + 1) = (png_byte)(v & 0xff);
\r
4139 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
\r
4140 /* Encode the alpha channel to the output gamma (the input channel is always
\r
4141 * linear.) Called only with color types that have an alpha channel. Needs the
\r
4145 png_do_encode_alpha(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
\r
4147 png_uint_32 row_width = row_info->width;
\r
4149 png_debug(1, "in png_do_encode_alpha");
\r
4151 if ((row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0)
\r
4153 if (row_info->bit_depth == 8)
\r
4155 png_bytep table = png_ptr->gamma_from_1;
\r
4157 if (table != NULL)
\r
4159 int step = (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 4 : 2;
\r
4161 /* The alpha channel is the last component: */
\r
4164 for (; row_width > 0; --row_width, row += step)
\r
4165 *row = table[*row];
\r
4171 else if (row_info->bit_depth == 16)
\r
4173 png_uint_16pp table = png_ptr->gamma_16_from_1;
\r
4174 int gamma_shift = png_ptr->gamma_shift;
\r
4176 if (table != NULL)
\r
4178 int step = (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 8 : 4;
\r
4180 /* The alpha channel is the last component: */
\r
4183 for (; row_width > 0; --row_width, row += step)
\r
4187 v = table[*(row + 1) >> gamma_shift][*row];
\r
4188 *row = (png_byte)((v >> 8) & 0xff);
\r
4189 *(row + 1) = (png_byte)(v & 0xff);
\r
4197 /* Only get to here if called with a weird row_info; no harm has been done,
\r
4198 * so just issue a warning.
\r
4200 png_warning(png_ptr, "png_do_encode_alpha: unexpected call");
\r
4204 #ifdef PNG_READ_EXPAND_SUPPORTED
\r
4205 /* Expands a palette row to an RGB or RGBA row depending
\r
4206 * upon whether you supply trans and num_trans.
\r
4209 png_do_expand_palette(png_structrp png_ptr, png_row_infop row_info,
\r
4210 png_bytep row, png_const_colorp palette, png_const_bytep trans_alpha,
\r
4216 png_uint_32 row_width=row_info->width;
\r
4218 png_debug(1, "in png_do_expand_palette");
\r
4220 if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
\r
4222 if (row_info->bit_depth < 8)
\r
4224 switch (row_info->bit_depth)
\r
4228 sp = row + (size_t)((row_width - 1) >> 3);
\r
4229 dp = row + (size_t)row_width - 1;
\r
4230 shift = 7 - (int)((row_width + 7) & 0x07);
\r
4231 for (i = 0; i < row_width; i++)
\r
4233 if ((*sp >> shift) & 0x01)
\r
4255 sp = row + (size_t)((row_width - 1) >> 2);
\r
4256 dp = row + (size_t)row_width - 1;
\r
4257 shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
\r
4258 for (i = 0; i < row_width; i++)
\r
4260 value = (*sp >> shift) & 0x03;
\r
4261 *dp = (png_byte)value;
\r
4278 sp = row + (size_t)((row_width - 1) >> 1);
\r
4279 dp = row + (size_t)row_width - 1;
\r
4280 shift = (int)((row_width & 0x01) << 2);
\r
4281 for (i = 0; i < row_width; i++)
\r
4283 value = (*sp >> shift) & 0x0f;
\r
4284 *dp = (png_byte)value;
\r
4302 row_info->bit_depth = 8;
\r
4303 row_info->pixel_depth = 8;
\r
4304 row_info->rowbytes = row_width;
\r
4307 if (row_info->bit_depth == 8)
\r
4310 if (num_trans > 0)
\r
4312 sp = row + (size_t)row_width - 1;
\r
4313 dp = row + ((size_t)row_width << 2) - 1;
\r
4316 #ifdef PNG_ARM_NEON_INTRINSICS_AVAILABLE
\r
4317 if (png_ptr->riffled_palette != NULL)
\r
4319 /* The RGBA optimization works with png_ptr->bit_depth == 8
\r
4320 * but sometimes row_info->bit_depth has been changed to 8.
\r
4321 * In these cases, the palette hasn't been riffled.
\r
4323 i = png_do_expand_palette_rgba8_neon(png_ptr, row_info, row,
\r
4327 PNG_UNUSED(png_ptr)
\r
4330 for (; i < row_width; i++)
\r
4332 if ((int)(*sp) >= num_trans)
\r
4335 *dp-- = trans_alpha[*sp];
\r
4336 *dp-- = palette[*sp].blue;
\r
4337 *dp-- = palette[*sp].green;
\r
4338 *dp-- = palette[*sp].red;
\r
4341 row_info->bit_depth = 8;
\r
4342 row_info->pixel_depth = 32;
\r
4343 row_info->rowbytes = row_width * 4;
\r
4344 row_info->color_type = 6;
\r
4345 row_info->channels = 4;
\r
4350 sp = row + (size_t)row_width - 1;
\r
4351 dp = row + (size_t)(row_width * 3) - 1;
\r
4353 #ifdef PNG_ARM_NEON_INTRINSICS_AVAILABLE
\r
4354 i = png_do_expand_palette_rgb8_neon(png_ptr, row_info, row,
\r
4357 PNG_UNUSED(png_ptr)
\r
4360 for (; i < row_width; i++)
\r
4362 *dp-- = palette[*sp].blue;
\r
4363 *dp-- = palette[*sp].green;
\r
4364 *dp-- = palette[*sp].red;
\r
4368 row_info->bit_depth = 8;
\r
4369 row_info->pixel_depth = 24;
\r
4370 row_info->rowbytes = row_width * 3;
\r
4371 row_info->color_type = 2;
\r
4372 row_info->channels = 3;
\r
4379 /* If the bit depth < 8, it is expanded to 8. Also, if the already
\r
4380 * expanded transparency value is supplied, an alpha channel is built.
\r
4383 png_do_expand(png_row_infop row_info, png_bytep row,
\r
4384 png_const_color_16p trans_color)
\r
4389 png_uint_32 row_width=row_info->width;
\r
4391 png_debug(1, "in png_do_expand");
\r
4393 if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
\r
4395 unsigned int gray = trans_color != NULL ? trans_color->gray : 0;
\r
4397 if (row_info->bit_depth < 8)
\r
4399 switch (row_info->bit_depth)
\r
4403 gray = (gray & 0x01) * 0xff;
\r
4404 sp = row + (size_t)((row_width - 1) >> 3);
\r
4405 dp = row + (size_t)row_width - 1;
\r
4406 shift = 7 - (int)((row_width + 7) & 0x07);
\r
4407 for (i = 0; i < row_width; i++)
\r
4409 if ((*sp >> shift) & 0x01)
\r
4431 gray = (gray & 0x03) * 0x55;
\r
4432 sp = row + (size_t)((row_width - 1) >> 2);
\r
4433 dp = row + (size_t)row_width - 1;
\r
4434 shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
\r
4435 for (i = 0; i < row_width; i++)
\r
4437 value = (*sp >> shift) & 0x03;
\r
4438 *dp = (png_byte)(value | (value << 2) | (value << 4) |
\r
4456 gray = (gray & 0x0f) * 0x11;
\r
4457 sp = row + (size_t)((row_width - 1) >> 1);
\r
4458 dp = row + (size_t)row_width - 1;
\r
4459 shift = (int)((1 - ((row_width + 1) & 0x01)) << 2);
\r
4460 for (i = 0; i < row_width; i++)
\r
4462 value = (*sp >> shift) & 0x0f;
\r
4463 *dp = (png_byte)(value | (value << 4));
\r
4482 row_info->bit_depth = 8;
\r
4483 row_info->pixel_depth = 8;
\r
4484 row_info->rowbytes = row_width;
\r
4487 if (trans_color != NULL)
\r
4489 if (row_info->bit_depth == 8)
\r
4491 gray = gray & 0xff;
\r
4492 sp = row + (size_t)row_width - 1;
\r
4493 dp = row + ((size_t)row_width << 1) - 1;
\r
4495 for (i = 0; i < row_width; i++)
\r
4497 if ((*sp & 0xffU) == gray)
\r
4507 else if (row_info->bit_depth == 16)
\r
4509 unsigned int gray_high = (gray >> 8) & 0xff;
\r
4510 unsigned int gray_low = gray & 0xff;
\r
4511 sp = row + row_info->rowbytes - 1;
\r
4512 dp = row + (row_info->rowbytes << 1) - 1;
\r
4513 for (i = 0; i < row_width; i++)
\r
4515 if ((*(sp - 1) & 0xffU) == gray_high &&
\r
4516 (*(sp) & 0xffU) == gray_low)
\r
4533 row_info->color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
\r
4534 row_info->channels = 2;
\r
4535 row_info->pixel_depth = (png_byte)(row_info->bit_depth << 1);
\r
4536 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
\r
4540 else if (row_info->color_type == PNG_COLOR_TYPE_RGB &&
\r
4541 trans_color != NULL)
\r
4543 if (row_info->bit_depth == 8)
\r
4545 png_byte red = (png_byte)(trans_color->red & 0xff);
\r
4546 png_byte green = (png_byte)(trans_color->green & 0xff);
\r
4547 png_byte blue = (png_byte)(trans_color->blue & 0xff);
\r
4548 sp = row + (size_t)row_info->rowbytes - 1;
\r
4549 dp = row + ((size_t)row_width << 2) - 1;
\r
4550 for (i = 0; i < row_width; i++)
\r
4552 if (*(sp - 2) == red && *(sp - 1) == green && *(sp) == blue)
\r
4563 else if (row_info->bit_depth == 16)
\r
4565 png_byte red_high = (png_byte)((trans_color->red >> 8) & 0xff);
\r
4566 png_byte green_high = (png_byte)((trans_color->green >> 8) & 0xff);
\r
4567 png_byte blue_high = (png_byte)((trans_color->blue >> 8) & 0xff);
\r
4568 png_byte red_low = (png_byte)(trans_color->red & 0xff);
\r
4569 png_byte green_low = (png_byte)(trans_color->green & 0xff);
\r
4570 png_byte blue_low = (png_byte)(trans_color->blue & 0xff);
\r
4571 sp = row + row_info->rowbytes - 1;
\r
4572 dp = row + ((size_t)row_width << 3) - 1;
\r
4573 for (i = 0; i < row_width; i++)
\r
4575 if (*(sp - 5) == red_high &&
\r
4576 *(sp - 4) == red_low &&
\r
4577 *(sp - 3) == green_high &&
\r
4578 *(sp - 2) == green_low &&
\r
4579 *(sp - 1) == blue_high &&
\r
4580 *(sp ) == blue_low)
\r
4600 row_info->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
\r
4601 row_info->channels = 4;
\r
4602 row_info->pixel_depth = (png_byte)(row_info->bit_depth << 2);
\r
4603 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
\r
4608 #ifdef PNG_READ_EXPAND_16_SUPPORTED
\r
4609 /* If the bit depth is 8 and the color type is not a palette type expand the
\r
4610 * whole row to 16 bits. Has no effect otherwise.
\r
4613 png_do_expand_16(png_row_infop row_info, png_bytep row)
\r
4615 if (row_info->bit_depth == 8 &&
\r
4616 row_info->color_type != PNG_COLOR_TYPE_PALETTE)
\r
4618 /* The row have a sequence of bytes containing [0..255] and we need
\r
4619 * to turn it into another row containing [0..65535], to do this we
\r
4622 * (input / 255) * 65535
\r
4624 * Which happens to be exactly input * 257 and this can be achieved
\r
4625 * simply by byte replication in place (copying backwards).
\r
4627 png_byte *sp = row + row_info->rowbytes; /* source, last byte + 1 */
\r
4628 png_byte *dp = sp + row_info->rowbytes; /* destination, end + 1 */
\r
4631 dp[-2] = dp[-1] = *--sp; dp -= 2;
\r
4634 row_info->rowbytes *= 2;
\r
4635 row_info->bit_depth = 16;
\r
4636 row_info->pixel_depth = (png_byte)(row_info->channels * 16);
\r
4641 #ifdef PNG_READ_QUANTIZE_SUPPORTED
\r
4643 png_do_quantize(png_row_infop row_info, png_bytep row,
\r
4644 png_const_bytep palette_lookup, png_const_bytep quantize_lookup)
\r
4648 png_uint_32 row_width=row_info->width;
\r
4650 png_debug(1, "in png_do_quantize");
\r
4652 if (row_info->bit_depth == 8)
\r
4654 if (row_info->color_type == PNG_COLOR_TYPE_RGB && palette_lookup)
\r
4659 for (i = 0; i < row_width; i++)
\r
4665 /* This looks real messy, but the compiler will reduce
\r
4666 * it down to a reasonable formula. For example, with
\r
4667 * 5 bits per color, we get:
\r
4668 * p = (((r >> 3) & 0x1f) << 10) |
\r
4669 * (((g >> 3) & 0x1f) << 5) |
\r
4670 * ((b >> 3) & 0x1f);
\r
4672 p = (((r >> (8 - PNG_QUANTIZE_RED_BITS)) &
\r
4673 ((1 << PNG_QUANTIZE_RED_BITS) - 1)) <<
\r
4674 (PNG_QUANTIZE_GREEN_BITS + PNG_QUANTIZE_BLUE_BITS)) |
\r
4675 (((g >> (8 - PNG_QUANTIZE_GREEN_BITS)) &
\r
4676 ((1 << PNG_QUANTIZE_GREEN_BITS) - 1)) <<
\r
4677 (PNG_QUANTIZE_BLUE_BITS)) |
\r
4678 ((b >> (8 - PNG_QUANTIZE_BLUE_BITS)) &
\r
4679 ((1 << PNG_QUANTIZE_BLUE_BITS) - 1));
\r
4681 *dp++ = palette_lookup[p];
\r
4684 row_info->color_type = PNG_COLOR_TYPE_PALETTE;
\r
4685 row_info->channels = 1;
\r
4686 row_info->pixel_depth = row_info->bit_depth;
\r
4687 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
\r
4690 else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
\r
4691 palette_lookup != NULL)
\r
4696 for (i = 0; i < row_width; i++)
\r
4703 p = (((r >> (8 - PNG_QUANTIZE_RED_BITS)) &
\r
4704 ((1 << PNG_QUANTIZE_RED_BITS) - 1)) <<
\r
4705 (PNG_QUANTIZE_GREEN_BITS + PNG_QUANTIZE_BLUE_BITS)) |
\r
4706 (((g >> (8 - PNG_QUANTIZE_GREEN_BITS)) &
\r
4707 ((1 << PNG_QUANTIZE_GREEN_BITS) - 1)) <<
\r
4708 (PNG_QUANTIZE_BLUE_BITS)) |
\r
4709 ((b >> (8 - PNG_QUANTIZE_BLUE_BITS)) &
\r
4710 ((1 << PNG_QUANTIZE_BLUE_BITS) - 1));
\r
4712 *dp++ = palette_lookup[p];
\r
4715 row_info->color_type = PNG_COLOR_TYPE_PALETTE;
\r
4716 row_info->channels = 1;
\r
4717 row_info->pixel_depth = row_info->bit_depth;
\r
4718 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
\r
4721 else if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
\r
4726 for (i = 0; i < row_width; i++, sp++)
\r
4728 *sp = quantize_lookup[*sp];
\r
4733 #endif /* READ_QUANTIZE */
\r
4735 /* Transform the row. The order of transformations is significant,
\r
4736 * and is very touchy. If you add a transformation, take care to
\r
4737 * decide how it fits in with the other transformations here.
\r
4739 void /* PRIVATE */
\r
4740 png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
\r
4742 png_debug(1, "in png_do_read_transformations");
\r
4744 if (png_ptr->row_buf == NULL)
\r
4746 /* Prior to 1.5.4 this output row/pass where the NULL pointer is, but this
\r
4747 * error is incredibly rare and incredibly easy to debug without this
\r
4750 png_error(png_ptr, "NULL row buffer");
\r
4753 /* The following is debugging; prior to 1.5.4 the code was never compiled in;
\r
4754 * in 1.5.4 PNG_FLAG_DETECT_UNINITIALIZED was added and the macro
\r
4755 * PNG_WARN_UNINITIALIZED_ROW removed. In 1.6 the new flag is set only for
\r
4756 * all transformations, however in practice the ROW_INIT always gets done on
\r
4757 * demand, if necessary.
\r
4759 if ((png_ptr->flags & PNG_FLAG_DETECT_UNINITIALIZED) != 0 &&
\r
4760 (png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
\r
4762 /* Application has failed to call either png_read_start_image() or
\r
4763 * png_read_update_info() after setting transforms that expand pixels.
\r
4764 * This check added to libpng-1.2.19 (but not enabled until 1.5.4).
\r
4766 png_error(png_ptr, "Uninitialized row");
\r
4769 #ifdef PNG_READ_EXPAND_SUPPORTED
\r
4770 if ((png_ptr->transformations & PNG_EXPAND) != 0)
\r
4772 if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
\r
4774 #ifdef PNG_ARM_NEON_INTRINSICS_AVAILABLE
\r
4775 if ((png_ptr->num_trans > 0) && (png_ptr->bit_depth == 8))
\r
4777 if (png_ptr->riffled_palette == NULL)
\r
4779 /* Initialize the accelerated palette expansion. */
\r
4780 png_ptr->riffled_palette =
\r
4781 (png_bytep)png_malloc(png_ptr, 256 * 4);
\r
4782 png_riffle_palette_neon(png_ptr);
\r
4786 png_do_expand_palette(png_ptr, row_info, png_ptr->row_buf + 1,
\r
4787 png_ptr->palette, png_ptr->trans_alpha, png_ptr->num_trans);
\r
4792 if (png_ptr->num_trans != 0 &&
\r
4793 (png_ptr->transformations & PNG_EXPAND_tRNS) != 0)
\r
4794 png_do_expand(row_info, png_ptr->row_buf + 1,
\r
4795 &(png_ptr->trans_color));
\r
4798 png_do_expand(row_info, png_ptr->row_buf + 1, NULL);
\r
4803 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
\r
4804 if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0 &&
\r
4805 (png_ptr->transformations & PNG_COMPOSE) == 0 &&
\r
4806 (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
\r
4807 row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
\r
4808 png_do_strip_channel(row_info, png_ptr->row_buf + 1,
\r
4809 0 /* at_start == false, because SWAP_ALPHA happens later */);
\r
4812 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
\r
4813 if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
\r
4816 png_do_rgb_to_gray(png_ptr, row_info,
\r
4817 png_ptr->row_buf + 1);
\r
4819 if (rgb_error != 0)
\r
4821 png_ptr->rgb_to_gray_status=1;
\r
4822 if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
\r
4823 PNG_RGB_TO_GRAY_WARN)
\r
4824 png_warning(png_ptr, "png_do_rgb_to_gray found nongray pixel");
\r
4826 if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
\r
4827 PNG_RGB_TO_GRAY_ERR)
\r
4828 png_error(png_ptr, "png_do_rgb_to_gray found nongray pixel");
\r
4833 /* From Andreas Dilger e-mail to png-implement, 26 March 1998:
\r
4835 * In most cases, the "simple transparency" should be done prior to doing
\r
4836 * gray-to-RGB, or you will have to test 3x as many bytes to check if a
\r
4837 * pixel is transparent. You would also need to make sure that the
\r
4838 * transparency information is upgraded to RGB.
\r
4840 * To summarize, the current flow is:
\r
4841 * - Gray + simple transparency -> compare 1 or 2 gray bytes and composite
\r
4842 * with background "in place" if transparent,
\r
4843 * convert to RGB if necessary
\r
4844 * - Gray + alpha -> composite with gray background and remove alpha bytes,
\r
4845 * convert to RGB if necessary
\r
4847 * To support RGB backgrounds for gray images we need:
\r
4848 * - Gray + simple transparency -> convert to RGB + simple transparency,
\r
4849 * compare 3 or 6 bytes and composite with
\r
4850 * background "in place" if transparent
\r
4851 * (3x compare/pixel compared to doing
\r
4852 * composite with gray bkgrnd)
\r
4853 * - Gray + alpha -> convert to RGB + alpha, composite with background and
\r
4854 * remove alpha bytes (3x float
\r
4855 * operations/pixel compared with composite
\r
4856 * on gray background)
\r
4858 * Greg's change will do this. The reason it wasn't done before is for
\r
4859 * performance, as this increases the per-pixel operations. If we would check
\r
4860 * in advance if the background was gray or RGB, and position the gray-to-RGB
\r
4861 * transform appropriately, then it would save a lot of work/time.
\r
4864 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
\r
4865 /* If gray -> RGB, do so now only if background is non-gray; else do later
\r
4866 * for performance reasons
\r
4868 if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0 &&
\r
4869 (png_ptr->mode & PNG_BACKGROUND_IS_GRAY) == 0)
\r
4870 png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
\r
4873 #if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
\r
4874 defined(PNG_READ_ALPHA_MODE_SUPPORTED)
\r
4875 if ((png_ptr->transformations & PNG_COMPOSE) != 0)
\r
4876 png_do_compose(row_info, png_ptr->row_buf + 1, png_ptr);
\r
4879 #ifdef PNG_READ_GAMMA_SUPPORTED
\r
4880 if ((png_ptr->transformations & PNG_GAMMA) != 0 &&
\r
4881 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
\r
4882 /* Because RGB_TO_GRAY does the gamma transform. */
\r
4883 (png_ptr->transformations & PNG_RGB_TO_GRAY) == 0 &&
\r
4885 #if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
\r
4886 defined(PNG_READ_ALPHA_MODE_SUPPORTED)
\r
4887 /* Because PNG_COMPOSE does the gamma transform if there is something to
\r
4888 * do (if there is an alpha channel or transparency.)
\r
4890 !((png_ptr->transformations & PNG_COMPOSE) != 0 &&
\r
4891 ((png_ptr->num_trans != 0) ||
\r
4892 (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)) &&
\r
4894 /* Because png_init_read_transformations transforms the palette, unless
\r
4895 * RGB_TO_GRAY will do the transform.
\r
4897 (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE))
\r
4898 png_do_gamma(row_info, png_ptr->row_buf + 1, png_ptr);
\r
4901 #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
\r
4902 if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0 &&
\r
4903 (png_ptr->transformations & PNG_COMPOSE) != 0 &&
\r
4904 (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
\r
4905 row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
\r
4906 png_do_strip_channel(row_info, png_ptr->row_buf + 1,
\r
4907 0 /* at_start == false, because SWAP_ALPHA happens later */);
\r
4910 #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
\r
4911 if ((png_ptr->transformations & PNG_ENCODE_ALPHA) != 0 &&
\r
4912 (row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0)
\r
4913 png_do_encode_alpha(row_info, png_ptr->row_buf + 1, png_ptr);
\r
4916 #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
\r
4917 if ((png_ptr->transformations & PNG_SCALE_16_TO_8) != 0)
\r
4918 png_do_scale_16_to_8(row_info, png_ptr->row_buf + 1);
\r
4921 #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
\r
4922 /* There is no harm in doing both of these because only one has any effect,
\r
4923 * by putting the 'scale' option first if the app asks for scale (either by
\r
4924 * calling the API or in a TRANSFORM flag) this is what happens.
\r
4926 if ((png_ptr->transformations & PNG_16_TO_8) != 0)
\r
4927 png_do_chop(row_info, png_ptr->row_buf + 1);
\r
4930 #ifdef PNG_READ_QUANTIZE_SUPPORTED
\r
4931 if ((png_ptr->transformations & PNG_QUANTIZE) != 0)
\r
4933 png_do_quantize(row_info, png_ptr->row_buf + 1,
\r
4934 png_ptr->palette_lookup, png_ptr->quantize_index);
\r
4936 if (row_info->rowbytes == 0)
\r
4937 png_error(png_ptr, "png_do_quantize returned rowbytes=0");
\r
4939 #endif /* READ_QUANTIZE */
\r
4941 #ifdef PNG_READ_EXPAND_16_SUPPORTED
\r
4942 /* Do the expansion now, after all the arithmetic has been done. Notice
\r
4943 * that previous transformations can handle the PNG_EXPAND_16 flag if this
\r
4944 * is efficient (particularly true in the case of gamma correction, where
\r
4945 * better accuracy results faster!)
\r
4947 if ((png_ptr->transformations & PNG_EXPAND_16) != 0)
\r
4948 png_do_expand_16(row_info, png_ptr->row_buf + 1);
\r
4951 #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
\r
4952 /* NOTE: moved here in 1.5.4 (from much later in this list.) */
\r
4953 if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0 &&
\r
4954 (png_ptr->mode & PNG_BACKGROUND_IS_GRAY) != 0)
\r
4955 png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
\r
4958 #ifdef PNG_READ_INVERT_SUPPORTED
\r
4959 if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
\r
4960 png_do_invert(row_info, png_ptr->row_buf + 1);
\r
4963 #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
\r
4964 if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0)
\r
4965 png_do_read_invert_alpha(row_info, png_ptr->row_buf + 1);
\r
4968 #ifdef PNG_READ_SHIFT_SUPPORTED
\r
4969 if ((png_ptr->transformations & PNG_SHIFT) != 0)
\r
4970 png_do_unshift(row_info, png_ptr->row_buf + 1,
\r
4971 &(png_ptr->shift));
\r
4974 #ifdef PNG_READ_PACK_SUPPORTED
\r
4975 if ((png_ptr->transformations & PNG_PACK) != 0)
\r
4976 png_do_unpack(row_info, png_ptr->row_buf + 1);
\r
4979 #ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
\r
4980 /* Added at libpng-1.5.10 */
\r
4981 if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
\r
4982 png_ptr->num_palette_max >= 0)
\r
4983 png_do_check_palette_indexes(png_ptr, row_info);
\r
4986 #ifdef PNG_READ_BGR_SUPPORTED
\r
4987 if ((png_ptr->transformations & PNG_BGR) != 0)
\r
4988 png_do_bgr(row_info, png_ptr->row_buf + 1);
\r
4991 #ifdef PNG_READ_PACKSWAP_SUPPORTED
\r
4992 if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
\r
4993 png_do_packswap(row_info, png_ptr->row_buf + 1);
\r
4996 #ifdef PNG_READ_FILLER_SUPPORTED
\r
4997 if ((png_ptr->transformations & PNG_FILLER) != 0)
\r
4998 png_do_read_filler(row_info, png_ptr->row_buf + 1,
\r
4999 (png_uint_32)png_ptr->filler, png_ptr->flags);
\r
5002 #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
\r
5003 if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0)
\r
5004 png_do_read_swap_alpha(row_info, png_ptr->row_buf + 1);
\r
5007 #ifdef PNG_READ_16BIT_SUPPORTED
\r
5008 #ifdef PNG_READ_SWAP_SUPPORTED
\r
5009 if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
\r
5010 png_do_swap(row_info, png_ptr->row_buf + 1);
\r
5014 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
\r
5015 if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
\r
5017 if (png_ptr->read_user_transform_fn != NULL)
\r
5018 (*(png_ptr->read_user_transform_fn)) /* User read transform function */
\r
5019 (png_ptr, /* png_ptr */
\r
5020 row_info, /* row_info: */
\r
5021 /* png_uint_32 width; width of row */
\r
5022 /* size_t rowbytes; number of bytes in row */
\r
5023 /* png_byte color_type; color type of pixels */
\r
5024 /* png_byte bit_depth; bit depth of samples */
\r
5025 /* png_byte channels; number of channels (1-4) */
\r
5026 /* png_byte pixel_depth; bits per pixel (depth*channels) */
\r
5027 png_ptr->row_buf + 1); /* start of pixel data for row */
\r
5028 #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
\r
5029 if (png_ptr->user_transform_depth != 0)
\r
5030 row_info->bit_depth = png_ptr->user_transform_depth;
\r
5032 if (png_ptr->user_transform_channels != 0)
\r
5033 row_info->channels = png_ptr->user_transform_channels;
\r
5035 row_info->pixel_depth = (png_byte)(row_info->bit_depth *
\r
5036 row_info->channels);
\r
5038 row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_info->width);
\r
5043 #endif /* READ_TRANSFORMS */
\r
projects / irrlicht.git / blob