Dlib库19.0.zip

/* pngrtran.c - transforms the data in a row for PNG readers * * Last changed in libpng 1.6.4 [August 21, 2013] * Copyright (c) 1998-2013 Glenn Randers-Pehrson * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger) * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.) * * This code is released under the libpng license. * For conditions of distribution and use, see the disclaimer * and license in png.h * * This file contains functions optionally called by an application * in order to tell libpng how to handle data when reading a PNG. * Transformations that are used in both reading and writing are * in pngtrans.c. */ #include "pngpriv.h" #ifdef PNG_READ_SUPPORTED /* Set the action on getting a CRC error for an ancillary or critical chunk. */ void PNGAPI png_set_crc_action(png_structrp png_ptr, int crit_action, int ancil_action) { png_debug(1, "in png_set_crc_action"); if (png_ptr == NULL) return; /* Tell libpng how we react to CRC errors in critical chunks */ switch (crit_action) { case PNG_CRC_NO_CHANGE: /* Leave setting as is */ break; case PNG_CRC_WARN_USE: /* Warn/use data */ png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK; png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE; break; case PNG_CRC_QUIET_USE: /* Quiet/use data */ png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK; png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE | PNG_FLAG_CRC_CRITICAL_IGNORE; break; case PNG_CRC_WARN_DISCARD: /* Not a valid action for critical data */ png_warning(png_ptr, "Can't discard critical data on CRC error"); case PNG_CRC_ERROR_QUIT: /* Error/quit */ case PNG_CRC_DEFAULT: default: png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK; break; } /* Tell libpng how we react to CRC errors in ancillary chunks */ switch (ancil_action) { case PNG_CRC_NO_CHANGE: /* Leave setting as is */ break; case PNG_CRC_WARN_USE: /* Warn/use data */ png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK; png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE; break; case PNG_CRC_QUIET_USE: /* Quiet/use data */ png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK; png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN; break; case PNG_CRC_ERROR_QUIT: /* Error/quit */ png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK; png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_NOWARN; break; case PNG_CRC_WARN_DISCARD: /* Warn/discard data */ case PNG_CRC_DEFAULT: default: png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK; break; } } #ifdef PNG_READ_TRANSFORMS_SUPPORTED /* Is it OK to set a transformation now? Only if png_start_read_image or * png_read_update_info have not been called. It is not necessary for the IHDR * to have been read in all cases, the parameter allows for this check too. */ static int png_rtran_ok(png_structrp png_ptr, int need_IHDR) { if (png_ptr != NULL) { if (png_ptr->flags & PNG_FLAG_ROW_INIT) png_app_error(png_ptr, "invalid after png_start_read_image or png_read_update_info"); else if (need_IHDR && (png_ptr->mode & PNG_HAVE_IHDR) == 0) png_app_error(png_ptr, "invalid before the PNG header has been read"); else { /* Turn on failure to initialize correctly for all transforms. */ png_ptr->flags |= PNG_FLAG_DETECT_UNINITIALIZED; return 1; /* Ok */ } } return 0; /* no png_error possible! */ } #endif #ifdef PNG_READ_BACKGROUND_SUPPORTED /* Handle alpha and tRNS via a background color */ void PNGFAPI png_set_background_fixed(png_structrp png_ptr, png_const_color_16p background_color, int background_gamma_code, int need_expand, png_fixed_point background_gamma) { png_debug(1, "in png_set_background_fixed"); if (!png_rtran_ok(png_ptr, 0) || background_color == NULL) return; if (background_gamma_code == PNG_BACKGROUND_GAMMA_UNKNOWN) { png_warning(png_ptr, "Application must supply a known background gamma"); return; } png_ptr->transformations |= PNG_COMPOSE | PNG_STRIP_ALPHA; png_ptr->transformations &= ~PNG_ENCODE_ALPHA; png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA; png_ptr->background = *background_color; png_ptr->background_gamma = background_gamma; png_ptr->background_gamma_type = (png_byte)(background_gamma_code); if (need_expand) png_ptr->transformations |= PNG_BACKGROUND_EXPAND; else png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND; } # ifdef PNG_FLOATING_POINT_SUPPORTED void PNGAPI png_set_background(png_structrp png_ptr, png_const_color_16p background_color, int background_gamma_code, int need_expand, double background_gamma) { png_set_background_fixed(png_ptr, background_color, background_gamma_code, need_expand, png_fixed(png_ptr, background_gamma, "png_set_background")); } # endif /* FLOATING_POINT */ #endif /* READ_BACKGROUND */ /* Scale 16-bit depth files to 8-bit depth. If both of these are set then the * one that pngrtran does first (scale) happens. This is necessary to allow the * TRANSFORM and API behavior to be somewhat consistent, and it's simpler. */ #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED void PNGAPI png_set_scale_16(png_structrp png_ptr) { png_debug(1, "in png_set_scale_16"); if (!png_rtran_ok(png_ptr, 0)) return; png_ptr->transformations |= PNG_SCALE_16_TO_8; } #endif #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED /* Chop 16-bit depth files to 8-bit depth */ void PNGAPI png_set_strip_16(png_structrp png_ptr) { png_debug(1, "in png_set_strip_16"); if (!png_rtran_ok(png_ptr, 0)) return; png_ptr->transformations |= PNG_16_TO_8; } #endif #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED void PNGAPI png_set_strip_alpha(png_structrp png_ptr) { png_debug(1, "in png_set_strip_alpha"); if (!png_rtran_ok(png_ptr, 0)) return; png_ptr->transformations |= PNG_STRIP_ALPHA; } #endif #if defined(PNG_READ_ALPHA_MODE_SUPPORTED) || defined(PNG_READ_GAMMA_SUPPORTED) static png_fixed_point translate_gamma_flags(png_structrp png_ptr, png_fixed_point output_gamma, int is_screen) { /* Check for flag values. The main reason for having the old Mac value as a * flag is that it is pretty near impossible to work out what the correct * value is from Apple documentation - a working Mac system is needed to * discover the value! */ if (output_gamma == PNG_DEFAULT_sRGB || output_gamma == PNG_FP_1 / PNG_DEFAULT_sRGB) { /* If there is no sRGB support this just sets the gamma to the standard * sRGB value. (This is a side effect of using this function!) */ # ifdef PNG_READ_sRGB_SUPPORTED png_ptr->flags |= PNG_FLAG_ASSUME_sRGB; # else PNG_UNUSED(png_ptr) # endif if (is_screen) output_gamma = PNG_GAMMA_sRGB; else output_gamma = PNG_GAMMA_sRGB_INVERSE; } else if (output_gamma == PNG_GAMMA_MAC_18 || output_gamma == PNG_FP_1 / PNG_GAMMA_MAC_18) { if (is_screen) output_gamma = PNG_GAMMA_MAC_OLD; else output_gamma = PNG_GAMMA_MAC_INVERSE; } return output_gamma; } # ifdef PNG_FLOATING_POINT_SUPPORTED static png_fixed_point convert_gamma_value(png_structrp png_ptr, double output_gamma) { /* The following silently ignores cases where fixed point (times 100,000) * gamma values are passed to the floating point API. This is safe and it * means the fix