[96425] | 1 |
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| 2 | /* pngrtran.c - transforms the data in a row for PNG readers
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| 3 | *
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[103316] | 4 | * Copyright (c) 2018-2024 Cosmin Truta
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[96425] | 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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| 8 | *
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| 9 | * This code is released under the libpng license.
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| 10 | * For conditions of distribution and use, see the disclaimer
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| 11 | * and license in png.h
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| 12 | *
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| 13 | * This file contains 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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| 16 | * in pngtrans.c.
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| 17 | */
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| 18 |
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| 19 | #include "pngpriv.h"
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| 20 |
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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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[103316] | 24 | # if defined(_MSC_VER) && !defined(__clang__) && defined(_M_ARM64)
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[96425] | 25 | # include <arm64_neon.h>
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| 26 | # else
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| 27 | # include <arm_neon.h>
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| 28 | # endif
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| 29 | # endif
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| 30 | #endif
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| 31 |
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| 32 | #ifdef PNG_READ_SUPPORTED
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| 33 |
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| 34 | /* Set the action on getting a CRC error for an ancillary or critical chunk. */
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| 35 | void PNGAPI
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| 36 | png_set_crc_action(png_structrp png_ptr, int crit_action, int ancil_action)
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| 37 | {
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| 38 | png_debug(1, "in png_set_crc_action");
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| 39 |
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| 40 | if (png_ptr == NULL)
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| 41 | return;
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| 42 |
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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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| 45 | {
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| 46 | case PNG_CRC_NO_CHANGE: /* Leave setting as is */
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| 47 | break;
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| 48 |
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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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| 52 | break;
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| 53 |
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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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| 58 | break;
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| 59 |
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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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| 63 | /* FALLTHROUGH */
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| 64 | case PNG_CRC_ERROR_QUIT: /* Error/quit */
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| 65 |
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| 66 | case PNG_CRC_DEFAULT:
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| 67 | default:
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| 68 | png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
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| 69 | break;
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| 70 | }
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| 71 |
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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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| 74 | {
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| 75 | case PNG_CRC_NO_CHANGE: /* Leave setting as is */
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| 76 | break;
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| 77 |
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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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| 81 | break;
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| 82 |
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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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| 87 | break;
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| 88 |
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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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| 92 | break;
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| 93 |
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| 94 | case PNG_CRC_WARN_DISCARD: /* Warn/discard data */
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| 95 |
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| 96 | case PNG_CRC_DEFAULT:
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| 97 | default:
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| 98 | png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
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| 99 | break;
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| 100 | }
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| 101 | }
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| 102 |
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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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| 107 | * check too.
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| 108 | */
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| 109 | static int
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| 110 | png_rtran_ok(png_structrp png_ptr, int need_IHDR)
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| 111 | {
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| 112 | if (png_ptr != NULL)
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| 113 | {
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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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| 117 |
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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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| 120 |
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| 121 | else
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| 122 | {
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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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| 125 |
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| 126 | return 1; /* Ok */
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| 127 | }
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| 128 | }
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| 129 |
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| 130 | return 0; /* no png_error possible! */
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| 131 | }
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| 132 | #endif
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| 133 |
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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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| 136 | void PNGFAPI
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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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| 140 | {
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| 141 | png_debug(1, "in png_set_background_fixed");
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| 142 |
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| 143 | if (png_rtran_ok(png_ptr, 0) == 0 || background_color == NULL)
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| 144 | return;
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| 145 |
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| 146 | if (background_gamma_code == PNG_BACKGROUND_GAMMA_UNKNOWN)
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| 147 | {
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| 148 | png_warning(png_ptr, "Application must supply a known background gamma");
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| 149 | return;
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| 150 | }
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| 151 |
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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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| 155 |
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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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| 161 | else
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| 162 | png_ptr->transformations &= ~PNG_BACKGROUND_EXPAND;
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| 163 | }
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| 164 |
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| 165 | # ifdef PNG_FLOATING_POINT_SUPPORTED
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| 166 | void PNGAPI
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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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| 170 | {
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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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| 173 | }
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| 174 | # endif /* FLOATING_POINT */
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| 175 | #endif /* READ_BACKGROUND */
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| 176 |
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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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| 180 | */
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| 181 | #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
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| 182 | void PNGAPI
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| 183 | png_set_scale_16(png_structrp png_ptr)
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| 184 | {
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| 185 | png_debug(1, "in png_set_scale_16");
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| 186 |
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| 187 | if (png_rtran_ok(png_ptr, 0) == 0)
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| 188 | return;
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| 189 |
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| 190 | png_ptr->transformations |= PNG_SCALE_16_TO_8;
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| 191 | }
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| 192 | #endif
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| 193 |
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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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| 196 | void PNGAPI
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| 197 | png_set_strip_16(png_structrp png_ptr)
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| 198 | {
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| 199 | png_debug(1, "in png_set_strip_16");
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| 200 |
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| 201 | if (png_rtran_ok(png_ptr, 0) == 0)
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| 202 | return;
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| 203 |
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| 204 | png_ptr->transformations |= PNG_16_TO_8;
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| 205 | }
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| 206 | #endif
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| 207 |
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| 208 | #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
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| 209 | void PNGAPI
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| 210 | png_set_strip_alpha(png_structrp png_ptr)
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| 211 | {
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| 212 | png_debug(1, "in png_set_strip_alpha");
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| 213 |
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| 214 | if (png_rtran_ok(png_ptr, 0) == 0)
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| 215 | return;
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| 216 |
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| 217 | png_ptr->transformations |= PNG_STRIP_ALPHA;
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| 218 | }
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| 219 | #endif
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| 220 |
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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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| 224 | int is_screen)
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| 225 | {
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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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| 230 | */
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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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| 233 | {
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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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| 236 | */
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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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| 239 | # else
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| 240 | PNG_UNUSED(png_ptr)
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| 241 | # endif
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| 242 | if (is_screen != 0)
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| 243 | output_gamma = PNG_GAMMA_sRGB;
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| 244 | else
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| 245 | output_gamma = PNG_GAMMA_sRGB_INVERSE;
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| 246 | }
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| 247 |
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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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| 250 | {
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| 251 | if (is_screen != 0)
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| 252 | output_gamma = PNG_GAMMA_MAC_OLD;
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| 253 | else
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| 254 | output_gamma = PNG_GAMMA_MAC_INVERSE;
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| 255 | }
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| 256 |
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| 257 | return output_gamma;
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| 258 | }
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| 259 |
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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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| 263 | {
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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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| 270 | */
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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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| 273 |
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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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| 276 |
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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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| 279 |
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| 280 | return (png_fixed_point)output_gamma;
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| 281 | }
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| 282 | # endif
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| 283 | #endif /* READ_ALPHA_MODE || READ_GAMMA */
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| 284 |
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| 285 | #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
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| 286 | void PNGFAPI
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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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| 289 | {
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| 290 | int compose = 0;
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| 291 | png_fixed_point file_gamma;
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| 292 |
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[103316] | 293 | png_debug(1, "in png_set_alpha_mode_fixed");
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[96425] | 294 |
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| 295 | if (png_rtran_ok(png_ptr, 0) == 0)
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| 296 | return;
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| 297 |
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| 298 | output_gamma = translate_gamma_flags(png_ptr, output_gamma, 1/*screen*/);
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| 299 |
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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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| 305 | *
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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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| 308 | */
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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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| 311 |
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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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| 314 | */
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| 315 | file_gamma = png_reciprocal(output_gamma);
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| 316 |
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| 317 | /* There are really 8 possibilities here, composed of any combination
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| 318 | * of:
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| 319 | *
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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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| 323 | *
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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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| 327 | *
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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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| 332 | */
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| 333 | switch (mode)
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| 334 | {
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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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| 339 | break;
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| 340 |
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| 341 | case PNG_ALPHA_ASSOCIATED: /* color channels premultiplied */
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| 342 | compose = 1;
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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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| 347 | break;
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| 348 |
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| 349 | case PNG_ALPHA_OPTIMIZED: /* associated, non-opaque pixels linear */
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| 350 | compose = 1;
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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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| 354 | break;
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| 355 |
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| 356 | case PNG_ALPHA_BROKEN: /* associated, non-linear, alpha encoded */
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| 357 | compose = 1;
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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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| 360 | break;
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| 361 |
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| 362 | default:
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| 363 | png_error(png_ptr, "invalid alpha mode");
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| 364 | }
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| 365 |
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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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| 368 | * be ignored.)
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| 369 | */
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| 370 | if (png_ptr->colorspace.gamma == 0)
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| 371 | {
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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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| 374 | }
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| 375 |
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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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| 378 |
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| 379 | /* Finally, if pre-multiplying, set the background fields to achieve the
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| 380 | * desired result.
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| 381 | */
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| 382 | if (compose != 0)
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| 383 | {
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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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| 389 |
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| 390 | if ((png_ptr->transformations & PNG_COMPOSE) != 0)
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| 391 | png_error(png_ptr,
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| 392 | "conflicting calls to set alpha mode and background");
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| 393 |
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| 394 | png_ptr->transformations |= PNG_COMPOSE;
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| 395 | }
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| 396 | }
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| 397 |
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| 398 | # ifdef PNG_FLOATING_POINT_SUPPORTED
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| 399 | void PNGAPI
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| 400 | png_set_alpha_mode(png_structrp png_ptr, int mode, double output_gamma)
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| 401 | {
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| 402 | png_set_alpha_mode_fixed(png_ptr, mode, convert_gamma_value(png_ptr,
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| 403 | output_gamma));
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| 404 | }
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| 405 | # endif
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| 406 | #endif
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| 407 |
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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
|
---|
| 410 | * of elements in the palette, the maximum number of elements
|
---|
| 411 | * allowed, and a histogram if possible. If the current number
|
---|
| 412 | * of colors is greater than the maximum number, the palette will be
|
---|
| 413 | * modified to fit in the maximum number. "full_quantize" indicates
|
---|
| 414 | * whether we need a quantizing cube set up for RGB images, or if we
|
---|
| 415 | * simply are reducing the number of colors in a paletted image.
|
---|
| 416 | */
|
---|
| 417 |
|
---|
| 418 | typedef struct png_dsort_struct
|
---|
| 419 | {
|
---|
| 420 | struct png_dsort_struct * next;
|
---|
| 421 | png_byte left;
|
---|
| 422 | png_byte right;
|
---|
| 423 | } png_dsort;
|
---|
| 424 | typedef png_dsort * png_dsortp;
|
---|
| 425 | typedef png_dsort * * png_dsortpp;
|
---|
| 426 |
|
---|
| 427 | void PNGAPI
|
---|
| 428 | png_set_quantize(png_structrp png_ptr, png_colorp palette,
|
---|
| 429 | int num_palette, int maximum_colors, png_const_uint_16p histogram,
|
---|
| 430 | int full_quantize)
|
---|
| 431 | {
|
---|
| 432 | png_debug(1, "in png_set_quantize");
|
---|
| 433 |
|
---|
| 434 | if (png_rtran_ok(png_ptr, 0) == 0)
|
---|
| 435 | return;
|
---|
| 436 |
|
---|
| 437 | png_ptr->transformations |= PNG_QUANTIZE;
|
---|
| 438 |
|
---|
| 439 | if (full_quantize == 0)
|
---|
| 440 | {
|
---|
| 441 | int i;
|
---|
| 442 |
|
---|
| 443 | png_ptr->quantize_index = (png_bytep)png_malloc(png_ptr,
|
---|
| 444 | (png_alloc_size_t)((png_uint_32)num_palette * (sizeof (png_byte))));
|
---|
| 445 | for (i = 0; i < num_palette; i++)
|
---|
| 446 | png_ptr->quantize_index[i] = (png_byte)i;
|
---|
| 447 | }
|
---|
| 448 |
|
---|
| 449 | if (num_palette > maximum_colors)
|
---|
| 450 | {
|
---|
| 451 | if (histogram != NULL)
|
---|
| 452 | {
|
---|
| 453 | /* This is easy enough, just throw out the least used colors.
|
---|
| 454 | * Perhaps not the best solution, but good enough.
|
---|
| 455 | */
|
---|
| 456 |
|
---|
| 457 | int i;
|
---|
| 458 |
|
---|
| 459 | /* Initialize an array to sort colors */
|
---|
| 460 | png_ptr->quantize_sort = (png_bytep)png_malloc(png_ptr,
|
---|
| 461 | (png_alloc_size_t)((png_uint_32)num_palette * (sizeof (png_byte))));
|
---|
| 462 |
|
---|
| 463 | /* Initialize the quantize_sort array */
|
---|
| 464 | for (i = 0; i < num_palette; i++)
|
---|
| 465 | png_ptr->quantize_sort[i] = (png_byte)i;
|
---|
| 466 |
|
---|
| 467 | /* Find the least used palette entries by starting a
|
---|
| 468 | * bubble sort, and running it until we have sorted
|
---|
| 469 | * out enough colors. Note that we don't care about
|
---|
| 470 | * sorting all the colors, just finding which are
|
---|
| 471 | * least used.
|
---|
| 472 | */
|
---|
| 473 |
|
---|
| 474 | for (i = num_palette - 1; i >= maximum_colors; i--)
|
---|
| 475 | {
|
---|
| 476 | int done; /* To stop early if the list is pre-sorted */
|
---|
| 477 | int j;
|
---|
| 478 |
|
---|
| 479 | done = 1;
|
---|
| 480 | for (j = 0; j < i; j++)
|
---|
| 481 | {
|
---|
| 482 | if (histogram[png_ptr->quantize_sort[j]]
|
---|
| 483 | < histogram[png_ptr->quantize_sort[j + 1]])
|
---|
| 484 | {
|
---|
| 485 | png_byte t;
|
---|
| 486 |
|
---|
| 487 | t = png_ptr->quantize_sort[j];
|
---|
| 488 | png_ptr->quantize_sort[j] = png_ptr->quantize_sort[j + 1];
|
---|
| 489 | png_ptr->quantize_sort[j + 1] = t;
|
---|
| 490 | done = 0;
|
---|
| 491 | }
|
---|
| 492 | }
|
---|
| 493 |
|
---|
| 494 | if (done != 0)
|
---|
| 495 | break;
|
---|
| 496 | }
|
---|
| 497 |
|
---|
| 498 | /* Swap the palette around, and set up a table, if necessary */
|
---|
| 499 | if (full_quantize != 0)
|
---|
| 500 | {
|
---|
| 501 | int j = num_palette;
|
---|
| 502 |
|
---|
| 503 | /* Put all the useful colors within the max, but don't
|
---|
| 504 | * move the others.
|
---|
| 505 | */
|
---|
| 506 | for (i = 0; i < maximum_colors; i++)
|
---|
| 507 | {
|
---|
| 508 | if ((int)png_ptr->quantize_sort[i] >= maximum_colors)
|
---|
| 509 | {
|
---|
| 510 | do
|
---|
| 511 | j--;
|
---|
| 512 | while ((int)png_ptr->quantize_sort[j] >= maximum_colors);
|
---|
| 513 |
|
---|
| 514 | palette[i] = palette[j];
|
---|
| 515 | }
|
---|
| 516 | }
|
---|
| 517 | }
|
---|
| 518 | else
|
---|
| 519 | {
|
---|
| 520 | int j = num_palette;
|
---|
| 521 |
|
---|
| 522 | /* Move all the used colors inside the max limit, and
|
---|
| 523 | * develop a translation table.
|
---|
| 524 | */
|
---|
| 525 | for (i = 0; i < maximum_colors; i++)
|
---|
| 526 | {
|
---|
| 527 | /* Only move the colors we need to */
|
---|
| 528 | if ((int)png_ptr->quantize_sort[i] >= maximum_colors)
|
---|
| 529 | {
|
---|
| 530 | png_color tmp_color;
|
---|
| 531 |
|
---|
| 532 | do
|
---|
| 533 | j--;
|
---|
| 534 | while ((int)png_ptr->quantize_sort[j] >= maximum_colors);
|
---|
| 535 |
|
---|
| 536 | tmp_color = palette[j];
|
---|
| 537 | palette[j] = palette[i];
|
---|
| 538 | palette[i] = tmp_color;
|
---|
| 539 | /* Indicate where the color went */
|
---|
| 540 | png_ptr->quantize_index[j] = (png_byte)i;
|
---|
| 541 | png_ptr->quantize_index[i] = (png_byte)j;
|
---|
| 542 | }
|
---|
| 543 | }
|
---|
| 544 |
|
---|
| 545 | /* Find closest color for those colors we are not using */
|
---|
| 546 | for (i = 0; i < num_palette; i++)
|
---|
| 547 | {
|
---|
| 548 | if ((int)png_ptr->quantize_index[i] >= maximum_colors)
|
---|
| 549 | {
|
---|
| 550 | int min_d, k, min_k, d_index;
|
---|
| 551 |
|
---|
| 552 | /* Find the closest color to one we threw out */
|
---|
| 553 | d_index = png_ptr->quantize_index[i];
|
---|
| 554 | min_d = PNG_COLOR_DIST(palette[d_index], palette[0]);
|
---|
| 555 | for (k = 1, min_k = 0; k < maximum_colors; k++)
|
---|
| 556 | {
|
---|
| 557 | int d;
|
---|
| 558 |
|
---|
| 559 | d = PNG_COLOR_DIST(palette[d_index], palette[k]);
|
---|
| 560 |
|
---|
| 561 | if (d < min_d)
|
---|
| 562 | {
|
---|
| 563 | min_d = d;
|
---|
| 564 | min_k = k;
|
---|
| 565 | }
|
---|
| 566 | }
|
---|
| 567 | /* Point to closest color */
|
---|
| 568 | png_ptr->quantize_index[i] = (png_byte)min_k;
|
---|
| 569 | }
|
---|
| 570 | }
|
---|
| 571 | }
|
---|
| 572 | png_free(png_ptr, png_ptr->quantize_sort);
|
---|
| 573 | png_ptr->quantize_sort = NULL;
|
---|
| 574 | }
|
---|
| 575 | else
|
---|
| 576 | {
|
---|
| 577 | /* This is much harder to do simply (and quickly). Perhaps
|
---|
| 578 | * we need to go through a median cut routine, but those
|
---|
| 579 | * don't always behave themselves with only a few colors
|
---|
| 580 | * as input. So we will just find the closest two colors,
|
---|
| 581 | * and throw out one of them (chosen somewhat randomly).
|
---|
| 582 | * [We don't understand this at all, so if someone wants to
|
---|
| 583 | * work on improving it, be our guest - AED, GRP]
|
---|
| 584 | */
|
---|
| 585 | int i;
|
---|
| 586 | int max_d;
|
---|
| 587 | int num_new_palette;
|
---|
| 588 | png_dsortp t;
|
---|
| 589 | png_dsortpp hash;
|
---|
| 590 |
|
---|
| 591 | t = NULL;
|
---|
| 592 |
|
---|
| 593 | /* Initialize palette index arrays */
|
---|
| 594 | png_ptr->index_to_palette = (png_bytep)png_malloc(png_ptr,
|
---|
| 595 | (png_alloc_size_t)((png_uint_32)num_palette *
|
---|
| 596 | (sizeof (png_byte))));
|
---|
| 597 | png_ptr->palette_to_index = (png_bytep)png_malloc(png_ptr,
|
---|
| 598 | (png_alloc_size_t)((png_uint_32)num_palette *
|
---|
| 599 | (sizeof (png_byte))));
|
---|
| 600 |
|
---|
| 601 | /* Initialize the sort array */
|
---|
| 602 | for (i = 0; i < num_palette; i++)
|
---|
| 603 | {
|
---|
| 604 | png_ptr->index_to_palette[i] = (png_byte)i;
|
---|
| 605 | png_ptr->palette_to_index[i] = (png_byte)i;
|
---|
| 606 | }
|
---|
| 607 |
|
---|
| 608 | hash = (png_dsortpp)png_calloc(png_ptr, (png_alloc_size_t)(769 *
|
---|
| 609 | (sizeof (png_dsortp))));
|
---|
| 610 |
|
---|
| 611 | num_new_palette = num_palette;
|
---|
| 612 |
|
---|
| 613 | /* Initial wild guess at how far apart the farthest pixel
|
---|
| 614 | * pair we will be eliminating will be. Larger
|
---|
| 615 | * numbers mean more areas will be allocated, Smaller
|
---|
| 616 | * numbers run the risk of not saving enough data, and
|
---|
| 617 | * having to do this all over again.
|
---|
| 618 | *
|
---|
| 619 | * I have not done extensive checking on this number.
|
---|
| 620 | */
|
---|
| 621 | max_d = 96;
|
---|
| 622 |
|
---|
| 623 | while (num_new_palette > maximum_colors)
|
---|
| 624 | {
|
---|
| 625 | for (i = 0; i < num_new_palette - 1; i++)
|
---|
| 626 | {
|
---|
| 627 | int j;
|
---|
| 628 |
|
---|
| 629 | for (j = i + 1; j < num_new_palette; j++)
|
---|
| 630 | {
|
---|
| 631 | int d;
|
---|
| 632 |
|
---|
| 633 | d = PNG_COLOR_DIST(palette[i], palette[j]);
|
---|
| 634 |
|
---|
| 635 | if (d <= max_d)
|
---|
| 636 | {
|
---|
| 637 |
|
---|
| 638 | t = (png_dsortp)png_malloc_warn(png_ptr,
|
---|
| 639 | (png_alloc_size_t)(sizeof (png_dsort)));
|
---|
| 640 |
|
---|
| 641 | if (t == NULL)
|
---|
| 642 | break;
|
---|
| 643 |
|
---|
| 644 | t->next = hash[d];
|
---|
| 645 | t->left = (png_byte)i;
|
---|
| 646 | t->right = (png_byte)j;
|
---|
| 647 | hash[d] = t;
|
---|
| 648 | }
|
---|
| 649 | }
|
---|
| 650 | if (t == NULL)
|
---|
| 651 | break;
|
---|
| 652 | }
|
---|
| 653 |
|
---|
| 654 | if (t != NULL)
|
---|
| 655 | for (i = 0; i <= max_d; i++)
|
---|
| 656 | {
|
---|
| 657 | if (hash[i] != NULL)
|
---|
| 658 | {
|
---|
| 659 | png_dsortp p;
|
---|
| 660 |
|
---|
| 661 | for (p = hash[i]; p; p = p->next)
|
---|
| 662 | {
|
---|
| 663 | if ((int)png_ptr->index_to_palette[p->left]
|
---|
| 664 | < num_new_palette &&
|
---|
| 665 | (int)png_ptr->index_to_palette[p->right]
|
---|
| 666 | < num_new_palette)
|
---|
| 667 | {
|
---|
| 668 | int j, next_j;
|
---|
| 669 |
|
---|
| 670 | if (num_new_palette & 0x01)
|
---|
| 671 | {
|
---|
| 672 | j = p->left;
|
---|
| 673 | next_j = p->right;
|
---|
| 674 | }
|
---|
| 675 | else
|
---|
| 676 | {
|
---|
| 677 | j = p->right;
|
---|
| 678 | next_j = p->left;
|
---|
| 679 | }
|
---|
| 680 |
|
---|
| 681 | num_new_palette--;
|
---|
| 682 | palette[png_ptr->index_to_palette[j]]
|
---|
| 683 | = palette[num_new_palette];
|
---|
| 684 | if (full_quantize == 0)
|
---|
| 685 | {
|
---|
| 686 | int k;
|
---|
| 687 |
|
---|
| 688 | for (k = 0; k < num_palette; k++)
|
---|
| 689 | {
|
---|
| 690 | if (png_ptr->quantize_index[k] ==
|
---|
| 691 | png_ptr->index_to_palette[j])
|
---|
| 692 | png_ptr->quantize_index[k] =
|
---|
| 693 | png_ptr->index_to_palette[next_j];
|
---|
| 694 |
|
---|
| 695 | if ((int)png_ptr->quantize_index[k] ==
|
---|
| 696 | num_new_palette)
|
---|
| 697 | png_ptr->quantize_index[k] =
|
---|
| 698 | png_ptr->index_to_palette[j];
|
---|
| 699 | }
|
---|
| 700 | }
|
---|
| 701 |
|
---|
| 702 | png_ptr->index_to_palette[png_ptr->palette_to_index
|
---|
| 703 | [num_new_palette]] = png_ptr->index_to_palette[j];
|
---|
| 704 |
|
---|
| 705 | png_ptr->palette_to_index[png_ptr->index_to_palette[j]]
|
---|
| 706 | = png_ptr->palette_to_index[num_new_palette];
|
---|
| 707 |
|
---|
| 708 | png_ptr->index_to_palette[j] =
|
---|
| 709 | (png_byte)num_new_palette;
|
---|
| 710 |
|
---|
| 711 | png_ptr->palette_to_index[num_new_palette] =
|
---|
| 712 | (png_byte)j;
|
---|
| 713 | }
|
---|
| 714 | if (num_new_palette <= maximum_colors)
|
---|
| 715 | break;
|
---|
| 716 | }
|
---|
| 717 | if (num_new_palette <= maximum_colors)
|
---|
| 718 | break;
|
---|
| 719 | }
|
---|
| 720 | }
|
---|
| 721 |
|
---|
| 722 | for (i = 0; i < 769; i++)
|
---|
| 723 | {
|
---|
| 724 | if (hash[i] != NULL)
|
---|
| 725 | {
|
---|
| 726 | png_dsortp p = hash[i];
|
---|
| 727 | while (p)
|
---|
| 728 | {
|
---|
| 729 | t = p->next;
|
---|
| 730 | png_free(png_ptr, p);
|
---|
| 731 | p = t;
|
---|
| 732 | }
|
---|
| 733 | }
|
---|
| 734 | hash[i] = 0;
|
---|
| 735 | }
|
---|
| 736 | max_d += 96;
|
---|
| 737 | }
|
---|
| 738 | png_free(png_ptr, hash);
|
---|
| 739 | png_free(png_ptr, png_ptr->palette_to_index);
|
---|
| 740 | png_free(png_ptr, png_ptr->index_to_palette);
|
---|
| 741 | png_ptr->palette_to_index = NULL;
|
---|
| 742 | png_ptr->index_to_palette = NULL;
|
---|
| 743 | }
|
---|
| 744 | num_palette = maximum_colors;
|
---|
| 745 | }
|
---|
| 746 | if (png_ptr->palette == NULL)
|
---|
| 747 | {
|
---|
| 748 | png_ptr->palette = palette;
|
---|
| 749 | }
|
---|
| 750 | png_ptr->num_palette = (png_uint_16)num_palette;
|
---|
| 751 |
|
---|
| 752 | if (full_quantize != 0)
|
---|
| 753 | {
|
---|
| 754 | int i;
|
---|
| 755 | png_bytep distance;
|
---|
| 756 | int total_bits = PNG_QUANTIZE_RED_BITS + PNG_QUANTIZE_GREEN_BITS +
|
---|
| 757 | PNG_QUANTIZE_BLUE_BITS;
|
---|
| 758 | int num_red = (1 << PNG_QUANTIZE_RED_BITS);
|
---|
| 759 | int num_green = (1 << PNG_QUANTIZE_GREEN_BITS);
|
---|
| 760 | int num_blue = (1 << PNG_QUANTIZE_BLUE_BITS);
|
---|
| 761 | size_t num_entries = ((size_t)1 << total_bits);
|
---|
| 762 |
|
---|
| 763 | png_ptr->palette_lookup = (png_bytep)png_calloc(png_ptr,
|
---|
| 764 | (png_alloc_size_t)(num_entries * (sizeof (png_byte))));
|
---|
| 765 |
|
---|
| 766 | distance = (png_bytep)png_malloc(png_ptr, (png_alloc_size_t)(num_entries *
|
---|
| 767 | (sizeof (png_byte))));
|
---|
| 768 |
|
---|
| 769 | memset(distance, 0xff, num_entries * (sizeof (png_byte)));
|
---|
| 770 |
|
---|
| 771 | for (i = 0; i < num_palette; i++)
|
---|
| 772 | {
|
---|
| 773 | int ir, ig, ib;
|
---|
| 774 | int r = (palette[i].red >> (8 - PNG_QUANTIZE_RED_BITS));
|
---|
| 775 | int g = (palette[i].green >> (8 - PNG_QUANTIZE_GREEN_BITS));
|
---|
| 776 | int b = (palette[i].blue >> (8 - PNG_QUANTIZE_BLUE_BITS));
|
---|
| 777 |
|
---|
| 778 | for (ir = 0; ir < num_red; ir++)
|
---|
| 779 | {
|
---|
| 780 | /* int dr = abs(ir - r); */
|
---|
| 781 | int dr = ((ir > r) ? ir - r : r - ir);
|
---|
| 782 | int index_r = (ir << (PNG_QUANTIZE_BLUE_BITS +
|
---|
| 783 | PNG_QUANTIZE_GREEN_BITS));
|
---|
| 784 |
|
---|
| 785 | for (ig = 0; ig < num_green; ig++)
|
---|
| 786 | {
|
---|
| 787 | /* int dg = abs(ig - g); */
|
---|
| 788 | int dg = ((ig > g) ? ig - g : g - ig);
|
---|
| 789 | int dt = dr + dg;
|
---|
| 790 | int dm = ((dr > dg) ? dr : dg);
|
---|
| 791 | int index_g = index_r | (ig << PNG_QUANTIZE_BLUE_BITS);
|
---|
| 792 |
|
---|
| 793 | for (ib = 0; ib < num_blue; ib++)
|
---|
| 794 | {
|
---|
| 795 | int d_index = index_g | ib;
|
---|
| 796 | /* int db = abs(ib - b); */
|
---|
| 797 | int db = ((ib > b) ? ib - b : b - ib);
|
---|
| 798 | int dmax = ((dm > db) ? dm : db);
|
---|
| 799 | int d = dmax + dt + db;
|
---|
| 800 |
|
---|
| 801 | if (d < (int)distance[d_index])
|
---|
| 802 | {
|
---|
| 803 | distance[d_index] = (png_byte)d;
|
---|
| 804 | png_ptr->palette_lookup[d_index] = (png_byte)i;
|
---|
| 805 | }
|
---|
| 806 | }
|
---|
| 807 | }
|
---|
| 808 | }
|
---|
| 809 | }
|
---|
| 810 |
|
---|
| 811 | png_free(png_ptr, distance);
|
---|
| 812 | }
|
---|
| 813 | }
|
---|
| 814 | #endif /* READ_QUANTIZE */
|
---|
| 815 |
|
---|
| 816 | #ifdef PNG_READ_GAMMA_SUPPORTED
|
---|
| 817 | void PNGFAPI
|
---|
| 818 | png_set_gamma_fixed(png_structrp png_ptr, png_fixed_point scrn_gamma,
|
---|
| 819 | png_fixed_point file_gamma)
|
---|
| 820 | {
|
---|
| 821 | png_debug(1, "in png_set_gamma_fixed");
|
---|
| 822 |
|
---|
| 823 | if (png_rtran_ok(png_ptr, 0) == 0)
|
---|
| 824 | return;
|
---|
| 825 |
|
---|
| 826 | /* New in libpng-1.5.4 - reserve particular negative values as flags. */
|
---|
| 827 | scrn_gamma = translate_gamma_flags(png_ptr, scrn_gamma, 1/*screen*/);
|
---|
| 828 | file_gamma = translate_gamma_flags(png_ptr, file_gamma, 0/*file*/);
|
---|
| 829 |
|
---|
| 830 | /* Checking the gamma values for being >0 was added in 1.5.4 along with the
|
---|
| 831 | * premultiplied alpha support; this actually hides an undocumented feature
|
---|
| 832 | * of the previous implementation which allowed gamma processing to be
|
---|
| 833 | * disabled in background handling. There is no evidence (so far) that this
|
---|
| 834 | * was being used; however, png_set_background itself accepted and must still
|
---|
| 835 | * accept '0' for the gamma value it takes, because it isn't always used.
|
---|
| 836 | *
|
---|
| 837 | * Since this is an API change (albeit a very minor one that removes an
|
---|
| 838 | * undocumented API feature) the following checks were only enabled in
|
---|
| 839 | * libpng-1.6.0.
|
---|
| 840 | */
|
---|
| 841 | if (file_gamma <= 0)
|
---|
| 842 | png_error(png_ptr, "invalid file gamma in png_set_gamma");
|
---|
| 843 |
|
---|
| 844 | if (scrn_gamma <= 0)
|
---|
| 845 | png_error(png_ptr, "invalid screen gamma in png_set_gamma");
|
---|
| 846 |
|
---|
| 847 | /* Set the gamma values unconditionally - this overrides the value in the PNG
|
---|
| 848 | * file if a gAMA chunk was present. png_set_alpha_mode provides a
|
---|
| 849 | * different, easier, way to default the file gamma.
|
---|
| 850 | */
|
---|
| 851 | png_ptr->colorspace.gamma = file_gamma;
|
---|
| 852 | png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
|
---|
| 853 | png_ptr->screen_gamma = scrn_gamma;
|
---|
| 854 | }
|
---|
| 855 |
|
---|
| 856 | # ifdef PNG_FLOATING_POINT_SUPPORTED
|
---|
| 857 | void PNGAPI
|
---|
| 858 | png_set_gamma(png_structrp png_ptr, double scrn_gamma, double file_gamma)
|
---|
| 859 | {
|
---|
| 860 | png_set_gamma_fixed(png_ptr, convert_gamma_value(png_ptr, scrn_gamma),
|
---|
| 861 | convert_gamma_value(png_ptr, file_gamma));
|
---|
| 862 | }
|
---|
| 863 | # endif /* FLOATING_POINT */
|
---|
| 864 | #endif /* READ_GAMMA */
|
---|
| 865 |
|
---|
| 866 | #ifdef PNG_READ_EXPAND_SUPPORTED
|
---|
| 867 | /* Expand paletted images to RGB, expand grayscale images of
|
---|
| 868 | * less than 8-bit depth to 8-bit depth, and expand tRNS chunks
|
---|
| 869 | * to alpha channels.
|
---|
| 870 | */
|
---|
| 871 | void PNGAPI
|
---|
| 872 | png_set_expand(png_structrp png_ptr)
|
---|
| 873 | {
|
---|
| 874 | png_debug(1, "in png_set_expand");
|
---|
| 875 |
|
---|
| 876 | if (png_rtran_ok(png_ptr, 0) == 0)
|
---|
| 877 | return;
|
---|
| 878 |
|
---|
| 879 | png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
|
---|
| 880 | }
|
---|
| 881 |
|
---|
| 882 | /* GRR 19990627: the following three functions currently are identical
|
---|
| 883 | * to png_set_expand(). However, it is entirely reasonable that someone
|
---|
| 884 | * might wish to expand an indexed image to RGB but *not* expand a single,
|
---|
| 885 | * fully transparent palette entry to a full alpha channel--perhaps instead
|
---|
| 886 | * convert tRNS to the grayscale/RGB format (16-bit RGB value), or replace
|
---|
| 887 | * the transparent color with a particular RGB value, or drop tRNS entirely.
|
---|
| 888 | * IOW, a future version of the library may make the transformations flag
|
---|
| 889 | * a bit more fine-grained, with separate bits for each of these three
|
---|
| 890 | * functions.
|
---|
| 891 | *
|
---|
| 892 | * More to the point, these functions make it obvious what libpng will be
|
---|
| 893 | * doing, whereas "expand" can (and does) mean any number of things.
|
---|
| 894 | *
|
---|
| 895 | * GRP 20060307: In libpng-1.2.9, png_set_gray_1_2_4_to_8() was modified
|
---|
| 896 | * to expand only the sample depth but not to expand the tRNS to alpha
|
---|
| 897 | * and its name was changed to png_set_expand_gray_1_2_4_to_8().
|
---|
| 898 | */
|
---|
| 899 |
|
---|
| 900 | /* Expand paletted images to RGB. */
|
---|
| 901 | void PNGAPI
|
---|
| 902 | png_set_palette_to_rgb(png_structrp png_ptr)
|
---|
| 903 | {
|
---|
| 904 | png_debug(1, "in png_set_palette_to_rgb");
|
---|
| 905 |
|
---|
| 906 | if (png_rtran_ok(png_ptr, 0) == 0)
|
---|
| 907 | return;
|
---|
| 908 |
|
---|
| 909 | png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
|
---|
| 910 | }
|
---|
| 911 |
|
---|
| 912 | /* Expand grayscale images of less than 8-bit depth to 8 bits. */
|
---|
| 913 | void PNGAPI
|
---|
| 914 | png_set_expand_gray_1_2_4_to_8(png_structrp png_ptr)
|
---|
| 915 | {
|
---|
| 916 | png_debug(1, "in png_set_expand_gray_1_2_4_to_8");
|
---|
| 917 |
|
---|
| 918 | if (png_rtran_ok(png_ptr, 0) == 0)
|
---|
| 919 | return;
|
---|
| 920 |
|
---|
| 921 | png_ptr->transformations |= PNG_EXPAND;
|
---|
| 922 | }
|
---|
| 923 |
|
---|
| 924 | /* Expand tRNS chunks to alpha channels. */
|
---|
| 925 | void PNGAPI
|
---|
| 926 | png_set_tRNS_to_alpha(png_structrp png_ptr)
|
---|
| 927 | {
|
---|
| 928 | png_debug(1, "in png_set_tRNS_to_alpha");
|
---|
| 929 |
|
---|
| 930 | if (png_rtran_ok(png_ptr, 0) == 0)
|
---|
| 931 | return;
|
---|
| 932 |
|
---|
| 933 | png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
|
---|
| 934 | }
|
---|
| 935 | #endif /* READ_EXPAND */
|
---|
| 936 |
|
---|
| 937 | #ifdef PNG_READ_EXPAND_16_SUPPORTED
|
---|
| 938 | /* Expand to 16-bit channels, expand the tRNS chunk too (because otherwise
|
---|
| 939 | * it may not work correctly.)
|
---|
| 940 | */
|
---|
| 941 | void PNGAPI
|
---|
| 942 | png_set_expand_16(png_structrp png_ptr)
|
---|
| 943 | {
|
---|
| 944 | png_debug(1, "in png_set_expand_16");
|
---|
| 945 |
|
---|
| 946 | if (png_rtran_ok(png_ptr, 0) == 0)
|
---|
| 947 | return;
|
---|
| 948 |
|
---|
| 949 | png_ptr->transformations |= (PNG_EXPAND_16 | PNG_EXPAND | PNG_EXPAND_tRNS);
|
---|
| 950 | }
|
---|
| 951 | #endif
|
---|
| 952 |
|
---|
| 953 | #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
|
---|
| 954 | void PNGAPI
|
---|
| 955 | png_set_gray_to_rgb(png_structrp png_ptr)
|
---|
| 956 | {
|
---|
| 957 | png_debug(1, "in png_set_gray_to_rgb");
|
---|
| 958 |
|
---|
| 959 | if (png_rtran_ok(png_ptr, 0) == 0)
|
---|
| 960 | return;
|
---|
| 961 |
|
---|
| 962 | /* Because rgb must be 8 bits or more: */
|
---|
| 963 | png_set_expand_gray_1_2_4_to_8(png_ptr);
|
---|
| 964 | png_ptr->transformations |= PNG_GRAY_TO_RGB;
|
---|
| 965 | }
|
---|
| 966 | #endif
|
---|
| 967 |
|
---|
| 968 | #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
|
---|
| 969 | void PNGFAPI
|
---|
| 970 | png_set_rgb_to_gray_fixed(png_structrp png_ptr, int error_action,
|
---|
| 971 | png_fixed_point red, png_fixed_point green)
|
---|
| 972 | {
|
---|
[103316] | 973 | png_debug(1, "in png_set_rgb_to_gray_fixed");
|
---|
[96425] | 974 |
|
---|
| 975 | /* Need the IHDR here because of the check on color_type below. */
|
---|
| 976 | /* TODO: fix this */
|
---|
| 977 | if (png_rtran_ok(png_ptr, 1) == 0)
|
---|
| 978 | return;
|
---|
| 979 |
|
---|
| 980 | switch (error_action)
|
---|
| 981 | {
|
---|
| 982 | case PNG_ERROR_ACTION_NONE:
|
---|
| 983 | png_ptr->transformations |= PNG_RGB_TO_GRAY;
|
---|
| 984 | break;
|
---|
| 985 |
|
---|
| 986 | case PNG_ERROR_ACTION_WARN:
|
---|
| 987 | png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN;
|
---|
| 988 | break;
|
---|
| 989 |
|
---|
| 990 | case PNG_ERROR_ACTION_ERROR:
|
---|
| 991 | png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR;
|
---|
| 992 | break;
|
---|
| 993 |
|
---|
| 994 | default:
|
---|
| 995 | png_error(png_ptr, "invalid error action to rgb_to_gray");
|
---|
| 996 | }
|
---|
| 997 |
|
---|
| 998 | if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
|
---|
| 999 | #ifdef PNG_READ_EXPAND_SUPPORTED
|
---|
| 1000 | png_ptr->transformations |= PNG_EXPAND;
|
---|
| 1001 | #else
|
---|
| 1002 | {
|
---|
| 1003 | /* Make this an error in 1.6 because otherwise the application may assume
|
---|
| 1004 | * that it just worked and get a memory overwrite.
|
---|
| 1005 | */
|
---|
| 1006 | png_error(png_ptr,
|
---|
| 1007 | "Cannot do RGB_TO_GRAY without EXPAND_SUPPORTED");
|
---|
| 1008 |
|
---|
| 1009 | /* png_ptr->transformations &= ~PNG_RGB_TO_GRAY; */
|
---|
| 1010 | }
|
---|
| 1011 | #endif
|
---|
| 1012 | {
|
---|
| 1013 | if (red >= 0 && green >= 0 && red + green <= PNG_FP_1)
|
---|
| 1014 | {
|
---|
| 1015 | png_uint_16 red_int, green_int;
|
---|
| 1016 |
|
---|
| 1017 | /* NOTE: this calculation does not round, but this behavior is retained
|
---|
| 1018 | * for consistency; the inaccuracy is very small. The code here always
|
---|
| 1019 | * overwrites the coefficients, regardless of whether they have been
|
---|
| 1020 | * defaulted or set already.
|
---|
| 1021 | */
|
---|
| 1022 | red_int = (png_uint_16)(((png_uint_32)red*32768)/100000);
|
---|
| 1023 | green_int = (png_uint_16)(((png_uint_32)green*32768)/100000);
|
---|
| 1024 |
|
---|
| 1025 | png_ptr->rgb_to_gray_red_coeff = red_int;
|
---|
| 1026 | png_ptr->rgb_to_gray_green_coeff = green_int;
|
---|
| 1027 | png_ptr->rgb_to_gray_coefficients_set = 1;
|
---|
| 1028 | }
|
---|
| 1029 |
|
---|
| 1030 | else
|
---|
| 1031 | {
|
---|
| 1032 | if (red >= 0 && green >= 0)
|
---|
| 1033 | png_app_warning(png_ptr,
|
---|
| 1034 | "ignoring out of range rgb_to_gray coefficients");
|
---|
| 1035 |
|
---|
| 1036 | /* Use the defaults, from the cHRM chunk if set, else the historical
|
---|
| 1037 | * values which are close to the sRGB/HDTV/ITU-Rec 709 values. See
|
---|
| 1038 | * png_do_rgb_to_gray for more discussion of the values. In this case
|
---|
| 1039 | * the coefficients are not marked as 'set' and are not overwritten if
|
---|
| 1040 | * something has already provided a default.
|
---|
| 1041 | */
|
---|
| 1042 | if (png_ptr->rgb_to_gray_red_coeff == 0 &&
|
---|
| 1043 | png_ptr->rgb_to_gray_green_coeff == 0)
|
---|
| 1044 | {
|
---|
| 1045 | png_ptr->rgb_to_gray_red_coeff = 6968;
|
---|
| 1046 | png_ptr->rgb_to_gray_green_coeff = 23434;
|
---|
| 1047 | /* png_ptr->rgb_to_gray_blue_coeff = 2366; */
|
---|
| 1048 | }
|
---|
| 1049 | }
|
---|
| 1050 | }
|
---|
| 1051 | }
|
---|
| 1052 |
|
---|
| 1053 | #ifdef PNG_FLOATING_POINT_SUPPORTED
|
---|
| 1054 | /* Convert a RGB image to a grayscale of the same width. This allows us,
|
---|
| 1055 | * for example, to convert a 24 bpp RGB image into an 8 bpp grayscale image.
|
---|
| 1056 | */
|
---|
| 1057 |
|
---|
| 1058 | void PNGAPI
|
---|
| 1059 | png_set_rgb_to_gray(png_structrp png_ptr, int error_action, double red,
|
---|
| 1060 | double green)
|
---|
| 1061 | {
|
---|
| 1062 | png_set_rgb_to_gray_fixed(png_ptr, error_action,
|
---|
| 1063 | png_fixed(png_ptr, red, "rgb to gray red coefficient"),
|
---|
| 1064 | png_fixed(png_ptr, green, "rgb to gray green coefficient"));
|
---|
| 1065 | }
|
---|
| 1066 | #endif /* FLOATING POINT */
|
---|
| 1067 |
|
---|
| 1068 | #endif /* RGB_TO_GRAY */
|
---|
| 1069 |
|
---|
| 1070 | #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
|
---|
| 1071 | defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
|
---|
| 1072 | void PNGAPI
|
---|
| 1073 | png_set_read_user_transform_fn(png_structrp png_ptr, png_user_transform_ptr
|
---|
| 1074 | read_user_transform_fn)
|
---|
| 1075 | {
|
---|
| 1076 | png_debug(1, "in png_set_read_user_transform_fn");
|
---|
| 1077 |
|
---|
| 1078 | #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
|
---|
| 1079 | png_ptr->transformations |= PNG_USER_TRANSFORM;
|
---|
| 1080 | png_ptr->read_user_transform_fn = read_user_transform_fn;
|
---|
| 1081 | #endif
|
---|
| 1082 | }
|
---|
| 1083 | #endif
|
---|
| 1084 |
|
---|
| 1085 | #ifdef PNG_READ_TRANSFORMS_SUPPORTED
|
---|
| 1086 | #ifdef PNG_READ_GAMMA_SUPPORTED
|
---|
| 1087 | /* In the case of gamma transformations only do transformations on images where
|
---|
| 1088 | * the [file] gamma and screen_gamma are not close reciprocals, otherwise it
|
---|
| 1089 | * slows things down slightly, and also needlessly introduces small errors.
|
---|
| 1090 | */
|
---|
| 1091 | static int /* PRIVATE */
|
---|
| 1092 | png_gamma_threshold(png_fixed_point screen_gamma, png_fixed_point file_gamma)
|
---|
| 1093 | {
|
---|
| 1094 | /* PNG_GAMMA_THRESHOLD is the threshold for performing gamma
|
---|
| 1095 | * correction as a difference of the overall transform from 1.0
|
---|
| 1096 | *
|
---|
| 1097 | * We want to compare the threshold with s*f - 1, if we get
|
---|
| 1098 | * overflow here it is because of wacky gamma values so we
|
---|
| 1099 | * turn on processing anyway.
|
---|
| 1100 | */
|
---|
| 1101 | png_fixed_point gtest;
|
---|
| 1102 | return !png_muldiv(>est, screen_gamma, file_gamma, PNG_FP_1) ||
|
---|
| 1103 | png_gamma_significant(gtest);
|
---|
| 1104 | }
|
---|
| 1105 | #endif
|
---|
| 1106 |
|
---|
| 1107 | /* Initialize everything needed for the read. This includes modifying
|
---|
| 1108 | * the palette.
|
---|
| 1109 | */
|
---|
| 1110 |
|
---|
| 1111 | /* For the moment 'png_init_palette_transformations' and
|
---|
| 1112 | * 'png_init_rgb_transformations' only do some flag canceling optimizations.
|
---|
| 1113 | * The intent is that these two routines should have palette or rgb operations
|
---|
| 1114 | * extracted from 'png_init_read_transformations'.
|
---|
| 1115 | */
|
---|
| 1116 | static void /* PRIVATE */
|
---|
| 1117 | png_init_palette_transformations(png_structrp png_ptr)
|
---|
| 1118 | {
|
---|
| 1119 | /* Called to handle the (input) palette case. In png_do_read_transformations
|
---|
| 1120 | * the first step is to expand the palette if requested, so this code must
|
---|
| 1121 | * take care to only make changes that are invariant with respect to the
|
---|
| 1122 | * palette expansion, or only do them if there is no expansion.
|
---|
| 1123 | *
|
---|
| 1124 | * STRIP_ALPHA has already been handled in the caller (by setting num_trans
|
---|
| 1125 | * to 0.)
|
---|
| 1126 | */
|
---|
| 1127 | int input_has_alpha = 0;
|
---|
| 1128 | int input_has_transparency = 0;
|
---|
| 1129 |
|
---|
| 1130 | if (png_ptr->num_trans > 0)
|
---|
| 1131 | {
|
---|
| 1132 | int i;
|
---|
| 1133 |
|
---|
| 1134 | /* Ignore if all the entries are opaque (unlikely!) */
|
---|
| 1135 | for (i=0; i<png_ptr->num_trans; ++i)
|
---|
| 1136 | {
|
---|
| 1137 | if (png_ptr->trans_alpha[i] == 255)
|
---|
| 1138 | continue;
|
---|
| 1139 | else if (png_ptr->trans_alpha[i] == 0)
|
---|
| 1140 | input_has_transparency = 1;
|
---|
| 1141 | else
|
---|
| 1142 | {
|
---|
| 1143 | input_has_transparency = 1;
|
---|
| 1144 | input_has_alpha = 1;
|
---|
| 1145 | break;
|
---|
| 1146 | }
|
---|
| 1147 | }
|
---|
| 1148 | }
|
---|
| 1149 |
|
---|
| 1150 | /* If no alpha we can optimize. */
|
---|
| 1151 | if (input_has_alpha == 0)
|
---|
| 1152 | {
|
---|
| 1153 | /* Any alpha means background and associative alpha processing is
|
---|
| 1154 | * required, however if the alpha is 0 or 1 throughout OPTIMIZE_ALPHA
|
---|
| 1155 | * and ENCODE_ALPHA are irrelevant.
|
---|
| 1156 | */
|
---|
| 1157 | png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
|
---|
| 1158 | png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
|
---|
| 1159 |
|
---|
| 1160 | if (input_has_transparency == 0)
|
---|
| 1161 | png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND);
|
---|
| 1162 | }
|
---|
| 1163 |
|
---|
| 1164 | #if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
|
---|
| 1165 | /* png_set_background handling - deals with the complexity of whether the
|
---|
| 1166 | * background color is in the file format or the screen format in the case
|
---|
| 1167 | * where an 'expand' will happen.
|
---|
| 1168 | */
|
---|
| 1169 |
|
---|
| 1170 | /* The following code cannot be entered in the alpha pre-multiplication case
|
---|
| 1171 | * because PNG_BACKGROUND_EXPAND is cancelled below.
|
---|
| 1172 | */
|
---|
| 1173 | if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) != 0 &&
|
---|
| 1174 | (png_ptr->transformations & PNG_EXPAND) != 0)
|
---|
| 1175 | {
|
---|
| 1176 | {
|
---|
| 1177 | png_ptr->background.red =
|
---|
| 1178 | png_ptr->palette[png_ptr->background.index].red;
|
---|
| 1179 | png_ptr->background.green =
|
---|
| 1180 | png_ptr->palette[png_ptr->background.index].green;
|
---|
| 1181 | png_ptr->background.blue =
|
---|
| 1182 | png_ptr->palette[png_ptr->background.index].blue;
|
---|
| 1183 |
|
---|
| 1184 | #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
|
---|
| 1185 | if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0)
|
---|
| 1186 | {
|
---|
| 1187 | if ((png_ptr->transformations & PNG_EXPAND_tRNS) == 0)
|
---|
| 1188 | {
|
---|
| 1189 | /* Invert the alpha channel (in tRNS) unless the pixels are
|
---|
| 1190 | * going to be expanded, in which case leave it for later
|
---|
| 1191 | */
|
---|
| 1192 | int i, istop = png_ptr->num_trans;
|
---|
| 1193 |
|
---|
| 1194 | for (i = 0; i < istop; i++)
|
---|
| 1195 | png_ptr->trans_alpha[i] =
|
---|
| 1196 | (png_byte)(255 - png_ptr->trans_alpha[i]);
|
---|
| 1197 | }
|
---|
| 1198 | }
|
---|
| 1199 | #endif /* READ_INVERT_ALPHA */
|
---|
| 1200 | }
|
---|
| 1201 | } /* background expand and (therefore) no alpha association. */
|
---|
| 1202 | #endif /* READ_EXPAND && READ_BACKGROUND */
|
---|
| 1203 | }
|
---|
| 1204 |
|
---|
| 1205 | static void /* PRIVATE */
|
---|
| 1206 | png_init_rgb_transformations(png_structrp png_ptr)
|
---|
| 1207 | {
|
---|
| 1208 | /* Added to libpng-1.5.4: check the color type to determine whether there
|
---|
| 1209 | * is any alpha or transparency in the image and simply cancel the
|
---|
| 1210 | * background and alpha mode stuff if there isn't.
|
---|
| 1211 | */
|
---|
| 1212 | int input_has_alpha = (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0;
|
---|
| 1213 | int input_has_transparency = png_ptr->num_trans > 0;
|
---|
| 1214 |
|
---|
| 1215 | /* If no alpha we can optimize. */
|
---|
| 1216 | if (input_has_alpha == 0)
|
---|
| 1217 | {
|
---|
| 1218 | /* Any alpha means background and associative alpha processing is
|
---|
| 1219 | * required, however if the alpha is 0 or 1 throughout OPTIMIZE_ALPHA
|
---|
| 1220 | * and ENCODE_ALPHA are irrelevant.
|
---|
| 1221 | */
|
---|
| 1222 | # ifdef PNG_READ_ALPHA_MODE_SUPPORTED
|
---|
| 1223 | png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
|
---|
| 1224 | png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
|
---|
| 1225 | # endif
|
---|
| 1226 |
|
---|
| 1227 | if (input_has_transparency == 0)
|
---|
| 1228 | png_ptr->transformations &= ~(PNG_COMPOSE | PNG_BACKGROUND_EXPAND);
|
---|
| 1229 | }
|
---|
| 1230 |
|
---|
| 1231 | #if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
|
---|
| 1232 | /* png_set_background handling - deals with the complexity of whether the
|
---|
| 1233 | * background color is in the file format or the screen format in the case
|
---|
| 1234 | * where an 'expand' will happen.
|
---|
| 1235 | */
|
---|
| 1236 |
|
---|
| 1237 | /* The following code cannot be entered in the alpha pre-multiplication case
|
---|
| 1238 | * because PNG_BACKGROUND_EXPAND is cancelled below.
|
---|
| 1239 | */
|
---|
| 1240 | if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) != 0 &&
|
---|
| 1241 | (png_ptr->transformations & PNG_EXPAND) != 0 &&
|
---|
| 1242 | (png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
|
---|
| 1243 | /* i.e., GRAY or GRAY_ALPHA */
|
---|
| 1244 | {
|
---|
| 1245 | {
|
---|
| 1246 | /* Expand background and tRNS chunks */
|
---|
| 1247 | int gray = png_ptr->background.gray;
|
---|
| 1248 | int trans_gray = png_ptr->trans_color.gray;
|
---|
| 1249 |
|
---|
| 1250 | switch (png_ptr->bit_depth)
|
---|
| 1251 | {
|
---|
| 1252 | case 1:
|
---|
| 1253 | gray *= 0xff;
|
---|
| 1254 | trans_gray *= 0xff;
|
---|
| 1255 | break;
|
---|
| 1256 |
|
---|
| 1257 | case 2:
|
---|
| 1258 | gray *= 0x55;
|
---|
| 1259 | trans_gray *= 0x55;
|
---|
| 1260 | break;
|
---|
| 1261 |
|
---|
| 1262 | case 4:
|
---|
| 1263 | gray *= 0x11;
|
---|
| 1264 | trans_gray *= 0x11;
|
---|
| 1265 | break;
|
---|
| 1266 |
|
---|
| 1267 | default:
|
---|
| 1268 |
|
---|
| 1269 | case 8:
|
---|
| 1270 | /* FALLTHROUGH */ /* (Already 8 bits) */
|
---|
| 1271 |
|
---|
| 1272 | case 16:
|
---|
| 1273 | /* Already a full 16 bits */
|
---|
| 1274 | break;
|
---|
| 1275 | }
|
---|
| 1276 |
|
---|
| 1277 | png_ptr->background.red = png_ptr->background.green =
|
---|
| 1278 | png_ptr->background.blue = (png_uint_16)gray;
|
---|
| 1279 |
|
---|
| 1280 | if ((png_ptr->transformations & PNG_EXPAND_tRNS) == 0)
|
---|
| 1281 | {
|
---|
| 1282 | png_ptr->trans_color.red = png_ptr->trans_color.green =
|
---|
| 1283 | png_ptr->trans_color.blue = (png_uint_16)trans_gray;
|
---|
| 1284 | }
|
---|
| 1285 | }
|
---|
| 1286 | } /* background expand and (therefore) no alpha association. */
|
---|
| 1287 | #endif /* READ_EXPAND && READ_BACKGROUND */
|
---|
| 1288 | }
|
---|
| 1289 |
|
---|
| 1290 | void /* PRIVATE */
|
---|
| 1291 | png_init_read_transformations(png_structrp png_ptr)
|
---|
| 1292 | {
|
---|
| 1293 | png_debug(1, "in png_init_read_transformations");
|
---|
| 1294 |
|
---|
| 1295 | /* This internal function is called from png_read_start_row in pngrutil.c
|
---|
| 1296 | * and it is called before the 'rowbytes' calculation is done, so the code
|
---|
| 1297 | * in here can change or update the transformations flags.
|
---|
| 1298 | *
|
---|
| 1299 | * First do updates that do not depend on the details of the PNG image data
|
---|
| 1300 | * being processed.
|
---|
| 1301 | */
|
---|
| 1302 |
|
---|
| 1303 | #ifdef PNG_READ_GAMMA_SUPPORTED
|
---|
| 1304 | /* Prior to 1.5.4 these tests were performed from png_set_gamma, 1.5.4 adds
|
---|
| 1305 | * png_set_alpha_mode and this is another source for a default file gamma so
|
---|
| 1306 | * the test needs to be performed later - here. In addition prior to 1.5.4
|
---|
| 1307 | * the tests were repeated for the PALETTE color type here - this is no
|
---|
| 1308 | * longer necessary (and doesn't seem to have been necessary before.)
|
---|
| 1309 | */
|
---|
| 1310 | {
|
---|
| 1311 | /* The following temporary indicates if overall gamma correction is
|
---|
| 1312 | * required.
|
---|
| 1313 | */
|
---|
| 1314 | int gamma_correction = 0;
|
---|
| 1315 |
|
---|
| 1316 | if (png_ptr->colorspace.gamma != 0) /* has been set */
|
---|
| 1317 | {
|
---|
| 1318 | if (png_ptr->screen_gamma != 0) /* screen set too */
|
---|
| 1319 | gamma_correction = png_gamma_threshold(png_ptr->colorspace.gamma,
|
---|
| 1320 | png_ptr->screen_gamma);
|
---|
| 1321 |
|
---|
| 1322 | else
|
---|
| 1323 | /* Assume the output matches the input; a long time default behavior
|
---|
| 1324 | * of libpng, although the standard has nothing to say about this.
|
---|
| 1325 | */
|
---|
| 1326 | png_ptr->screen_gamma = png_reciprocal(png_ptr->colorspace.gamma);
|
---|
| 1327 | }
|
---|
| 1328 |
|
---|
| 1329 | else if (png_ptr->screen_gamma != 0)
|
---|
| 1330 | /* The converse - assume the file matches the screen, note that this
|
---|
| 1331 | * perhaps undesirable default can (from 1.5.4) be changed by calling
|
---|
| 1332 | * png_set_alpha_mode (even if the alpha handling mode isn't required
|
---|
| 1333 | * or isn't changed from the default.)
|
---|
| 1334 | */
|
---|
| 1335 | png_ptr->colorspace.gamma = png_reciprocal(png_ptr->screen_gamma);
|
---|
| 1336 |
|
---|
| 1337 | else /* neither are set */
|
---|
| 1338 | /* Just in case the following prevents any processing - file and screen
|
---|
| 1339 | * are both assumed to be linear and there is no way to introduce a
|
---|
| 1340 | * third gamma value other than png_set_background with 'UNIQUE', and,
|
---|
| 1341 | * prior to 1.5.4
|
---|
| 1342 | */
|
---|
| 1343 | png_ptr->screen_gamma = png_ptr->colorspace.gamma = PNG_FP_1;
|
---|
| 1344 |
|
---|
| 1345 | /* We have a gamma value now. */
|
---|
| 1346 | png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
|
---|
| 1347 |
|
---|
| 1348 | /* Now turn the gamma transformation on or off as appropriate. Notice
|
---|
| 1349 | * that PNG_GAMMA just refers to the file->screen correction. Alpha
|
---|
| 1350 | * composition may independently cause gamma correction because it needs
|
---|
| 1351 | * linear data (e.g. if the file has a gAMA chunk but the screen gamma
|
---|
| 1352 | * hasn't been specified.) In any case this flag may get turned off in
|
---|
| 1353 | * the code immediately below if the transform can be handled outside the
|
---|
| 1354 | * row loop.
|
---|
| 1355 | */
|
---|
| 1356 | if (gamma_correction != 0)
|
---|
| 1357 | png_ptr->transformations |= PNG_GAMMA;
|
---|
| 1358 |
|
---|
| 1359 | else
|
---|
| 1360 | png_ptr->transformations &= ~PNG_GAMMA;
|
---|
| 1361 | }
|
---|
| 1362 | #endif
|
---|
| 1363 |
|
---|
| 1364 | /* Certain transformations have the effect of preventing other
|
---|
| 1365 | * transformations that happen afterward in png_do_read_transformations;
|
---|
| 1366 | * resolve the interdependencies here. From the code of
|
---|
| 1367 | * png_do_read_transformations the order is:
|
---|
| 1368 | *
|
---|
| 1369 | * 1) PNG_EXPAND (including PNG_EXPAND_tRNS)
|
---|
| 1370 | * 2) PNG_STRIP_ALPHA (if no compose)
|
---|
| 1371 | * 3) PNG_RGB_TO_GRAY
|
---|
| 1372 | * 4) PNG_GRAY_TO_RGB iff !PNG_BACKGROUND_IS_GRAY
|
---|
| 1373 | * 5) PNG_COMPOSE
|
---|
| 1374 | * 6) PNG_GAMMA
|
---|
| 1375 | * 7) PNG_STRIP_ALPHA (if compose)
|
---|
| 1376 | * 8) PNG_ENCODE_ALPHA
|
---|
| 1377 | * 9) PNG_SCALE_16_TO_8
|
---|
| 1378 | * 10) PNG_16_TO_8
|
---|
| 1379 | * 11) PNG_QUANTIZE (converts to palette)
|
---|
| 1380 | * 12) PNG_EXPAND_16
|
---|
| 1381 | * 13) PNG_GRAY_TO_RGB iff PNG_BACKGROUND_IS_GRAY
|
---|
| 1382 | * 14) PNG_INVERT_MONO
|
---|
| 1383 | * 15) PNG_INVERT_ALPHA
|
---|
| 1384 | * 16) PNG_SHIFT
|
---|
| 1385 | * 17) PNG_PACK
|
---|
| 1386 | * 18) PNG_BGR
|
---|
| 1387 | * 19) PNG_PACKSWAP
|
---|
| 1388 | * 20) PNG_FILLER (includes PNG_ADD_ALPHA)
|
---|
| 1389 | * 21) PNG_SWAP_ALPHA
|
---|
| 1390 | * 22) PNG_SWAP_BYTES
|
---|
| 1391 | * 23) PNG_USER_TRANSFORM [must be last]
|
---|
| 1392 | */
|
---|
| 1393 | #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
|
---|
| 1394 | if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0 &&
|
---|
| 1395 | (png_ptr->transformations & PNG_COMPOSE) == 0)
|
---|
| 1396 | {
|
---|
| 1397 | /* Stripping the alpha channel happens immediately after the 'expand'
|
---|
| 1398 | * transformations, before all other transformation, so it cancels out
|
---|
| 1399 | * the alpha handling. It has the side effect negating the effect of
|
---|
| 1400 | * PNG_EXPAND_tRNS too:
|
---|
| 1401 | */
|
---|
| 1402 | png_ptr->transformations &= ~(PNG_BACKGROUND_EXPAND | PNG_ENCODE_ALPHA |
|
---|
| 1403 | PNG_EXPAND_tRNS);
|
---|
| 1404 | png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
|
---|
| 1405 |
|
---|
| 1406 | /* Kill the tRNS chunk itself too. Prior to 1.5.4 this did not happen
|
---|
| 1407 | * so transparency information would remain just so long as it wasn't
|
---|
| 1408 | * expanded. This produces unexpected API changes if the set of things
|
---|
| 1409 | * that do PNG_EXPAND_tRNS changes (perfectly possible given the
|
---|
| 1410 | * documentation - which says ask for what you want, accept what you
|
---|
| 1411 | * get.) This makes the behavior consistent from 1.5.4:
|
---|
| 1412 | */
|
---|
| 1413 | png_ptr->num_trans = 0;
|
---|
| 1414 | }
|
---|
| 1415 | #endif /* STRIP_ALPHA supported, no COMPOSE */
|
---|
| 1416 |
|
---|
| 1417 | #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
|
---|
| 1418 | /* If the screen gamma is about 1.0 then the OPTIMIZE_ALPHA and ENCODE_ALPHA
|
---|
| 1419 | * settings will have no effect.
|
---|
| 1420 | */
|
---|
| 1421 | if (png_gamma_significant(png_ptr->screen_gamma) == 0)
|
---|
| 1422 | {
|
---|
| 1423 | png_ptr->transformations &= ~PNG_ENCODE_ALPHA;
|
---|
| 1424 | png_ptr->flags &= ~PNG_FLAG_OPTIMIZE_ALPHA;
|
---|
| 1425 | }
|
---|
| 1426 | #endif
|
---|
| 1427 |
|
---|
| 1428 | #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
|
---|
| 1429 | /* Make sure the coefficients for the rgb to gray conversion are set
|
---|
| 1430 | * appropriately.
|
---|
| 1431 | */
|
---|
| 1432 | if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
|
---|
| 1433 | png_colorspace_set_rgb_coefficients(png_ptr);
|
---|
| 1434 | #endif
|
---|
| 1435 |
|
---|
| 1436 | #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
|
---|
| 1437 | #if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
|
---|
| 1438 | /* Detect gray background and attempt to enable optimization for
|
---|
| 1439 | * gray --> RGB case.
|
---|
| 1440 | *
|
---|
| 1441 | * Note: if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or
|
---|
| 1442 | * RGB_ALPHA (in which case need_expand is superfluous anyway), the
|
---|
| 1443 | * background color might actually be gray yet not be flagged as such.
|
---|
| 1444 | * This is not a problem for the current code, which uses
|
---|
| 1445 | * PNG_BACKGROUND_IS_GRAY only to decide when to do the
|
---|
| 1446 | * png_do_gray_to_rgb() transformation.
|
---|
| 1447 | *
|
---|
| 1448 | * TODO: this code needs to be revised to avoid the complexity and
|
---|
| 1449 | * interdependencies. The color type of the background should be recorded in
|
---|
| 1450 | * png_set_background, along with the bit depth, then the code has a record
|
---|
| 1451 | * of exactly what color space the background is currently in.
|
---|
| 1452 | */
|
---|
| 1453 | if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) != 0)
|
---|
| 1454 | {
|
---|
| 1455 | /* PNG_BACKGROUND_EXPAND: the background is in the file color space, so if
|
---|
| 1456 | * the file was grayscale the background value is gray.
|
---|
| 1457 | */
|
---|
| 1458 | if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) == 0)
|
---|
| 1459 | png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
|
---|
| 1460 | }
|
---|
| 1461 |
|
---|
| 1462 | else if ((png_ptr->transformations & PNG_COMPOSE) != 0)
|
---|
| 1463 | {
|
---|
| 1464 | /* PNG_COMPOSE: png_set_background was called with need_expand false,
|
---|
| 1465 | * so the color is in the color space of the output or png_set_alpha_mode
|
---|
| 1466 | * was called and the color is black. Ignore RGB_TO_GRAY because that
|
---|
| 1467 | * happens before GRAY_TO_RGB.
|
---|
| 1468 | */
|
---|
| 1469 | if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0)
|
---|
| 1470 | {
|
---|
| 1471 | if (png_ptr->background.red == png_ptr->background.green &&
|
---|
| 1472 | png_ptr->background.red == png_ptr->background.blue)
|
---|
| 1473 | {
|
---|
| 1474 | png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
|
---|
| 1475 | png_ptr->background.gray = png_ptr->background.red;
|
---|
| 1476 | }
|
---|
| 1477 | }
|
---|
| 1478 | }
|
---|
| 1479 | #endif /* READ_EXPAND && READ_BACKGROUND */
|
---|
| 1480 | #endif /* READ_GRAY_TO_RGB */
|
---|
| 1481 |
|
---|
| 1482 | /* For indexed PNG data (PNG_COLOR_TYPE_PALETTE) many of the transformations
|
---|
| 1483 | * can be performed directly on the palette, and some (such as rgb to gray)
|
---|
| 1484 | * can be optimized inside the palette. This is particularly true of the
|
---|
| 1485 | * composite (background and alpha) stuff, which can be pretty much all done
|
---|
| 1486 | * in the palette even if the result is expanded to RGB or gray afterward.
|
---|
| 1487 | *
|
---|
| 1488 | * NOTE: this is Not Yet Implemented, the code behaves as in 1.5.1 and
|
---|
| 1489 | * earlier and the palette stuff is actually handled on the first row. This
|
---|
| 1490 | * leads to the reported bug that the palette returned by png_get_PLTE is not
|
---|
| 1491 | * updated.
|
---|
| 1492 | */
|
---|
| 1493 | if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
|
---|
| 1494 | png_init_palette_transformations(png_ptr);
|
---|
| 1495 |
|
---|
| 1496 | else
|
---|
| 1497 | png_init_rgb_transformations(png_ptr);
|
---|
| 1498 |
|
---|
| 1499 | #if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
|
---|
| 1500 | defined(PNG_READ_EXPAND_16_SUPPORTED)
|
---|
| 1501 | if ((png_ptr->transformations & PNG_EXPAND_16) != 0 &&
|
---|
| 1502 | (png_ptr->transformations & PNG_COMPOSE) != 0 &&
|
---|
| 1503 | (png_ptr->transformations & PNG_BACKGROUND_EXPAND) == 0 &&
|
---|
| 1504 | png_ptr->bit_depth != 16)
|
---|
| 1505 | {
|
---|
| 1506 | /* TODO: fix this. Because the expand_16 operation is after the compose
|
---|
| 1507 | * handling the background color must be 8, not 16, bits deep, but the
|
---|
| 1508 | * application will supply a 16-bit value so reduce it here.
|
---|
| 1509 | *
|
---|
| 1510 | * The PNG_BACKGROUND_EXPAND code above does not expand to 16 bits at
|
---|
| 1511 | * present, so that case is ok (until do_expand_16 is moved.)
|
---|
| 1512 | *
|
---|
| 1513 | * NOTE: this discards the low 16 bits of the user supplied background
|
---|
| 1514 | * color, but until expand_16 works properly there is no choice!
|
---|
| 1515 | */
|
---|
| 1516 | # define CHOP(x) (x)=((png_uint_16)PNG_DIV257(x))
|
---|
| 1517 | CHOP(png_ptr->background.red);
|
---|
| 1518 | CHOP(png_ptr->background.green);
|
---|
| 1519 | CHOP(png_ptr->background.blue);
|
---|
| 1520 | CHOP(png_ptr->background.gray);
|
---|
| 1521 | # undef CHOP
|
---|
| 1522 | }
|
---|
| 1523 | #endif /* READ_BACKGROUND && READ_EXPAND_16 */
|
---|
| 1524 |
|
---|
| 1525 | #if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
|
---|
| 1526 | (defined(PNG_READ_SCALE_16_TO_8_SUPPORTED) || \
|
---|
| 1527 | defined(PNG_READ_STRIP_16_TO_8_SUPPORTED))
|
---|
| 1528 | if ((png_ptr->transformations & (PNG_16_TO_8|PNG_SCALE_16_TO_8)) != 0 &&
|
---|
| 1529 | (png_ptr->transformations & PNG_COMPOSE) != 0 &&
|
---|
| 1530 | (png_ptr->transformations & PNG_BACKGROUND_EXPAND) == 0 &&
|
---|
| 1531 | png_ptr->bit_depth == 16)
|
---|
| 1532 | {
|
---|
| 1533 | /* On the other hand, if a 16-bit file is to be reduced to 8-bits per
|
---|
| 1534 | * component this will also happen after PNG_COMPOSE and so the background
|
---|
| 1535 | * color must be pre-expanded here.
|
---|
| 1536 | *
|
---|
| 1537 | * TODO: fix this too.
|
---|
| 1538 | */
|
---|
| 1539 | png_ptr->background.red = (png_uint_16)(png_ptr->background.red * 257);
|
---|
| 1540 | png_ptr->background.green =
|
---|
| 1541 | (png_uint_16)(png_ptr->background.green * 257);
|
---|
| 1542 | png_ptr->background.blue = (png_uint_16)(png_ptr->background.blue * 257);
|
---|
| 1543 | png_ptr->background.gray = (png_uint_16)(png_ptr->background.gray * 257);
|
---|
| 1544 | }
|
---|
| 1545 | #endif
|
---|
| 1546 |
|
---|
| 1547 | /* NOTE: below 'PNG_READ_ALPHA_MODE_SUPPORTED' is presumed to also enable the
|
---|
| 1548 | * background support (see the comments in scripts/pnglibconf.dfa), this
|
---|
| 1549 | * allows pre-multiplication of the alpha channel to be implemented as
|
---|
| 1550 | * compositing on black. This is probably sub-optimal and has been done in
|
---|
| 1551 | * 1.5.4 betas simply to enable external critique and testing (i.e. to
|
---|
| 1552 | * implement the new API quickly, without lots of internal changes.)
|
---|
| 1553 | */
|
---|
| 1554 |
|
---|
| 1555 | #ifdef PNG_READ_GAMMA_SUPPORTED
|
---|
| 1556 | # ifdef PNG_READ_BACKGROUND_SUPPORTED
|
---|
| 1557 | /* Includes ALPHA_MODE */
|
---|
| 1558 | png_ptr->background_1 = png_ptr->background;
|
---|
| 1559 | # endif
|
---|
| 1560 |
|
---|
| 1561 | /* This needs to change - in the palette image case a whole set of tables are
|
---|
| 1562 | * built when it would be quicker to just calculate the correct value for
|
---|
| 1563 | * each palette entry directly. Also, the test is too tricky - why check
|
---|
| 1564 | * PNG_RGB_TO_GRAY if PNG_GAMMA is not set? The answer seems to be that
|
---|
| 1565 | * PNG_GAMMA is cancelled even if the gamma is known? The test excludes the
|
---|
| 1566 | * PNG_COMPOSE case, so apparently if there is no *overall* gamma correction
|
---|
| 1567 | * the gamma tables will not be built even if composition is required on a
|
---|
| 1568 | * gamma encoded value.
|
---|
| 1569 | *
|
---|
| 1570 | * In 1.5.4 this is addressed below by an additional check on the individual
|
---|
| 1571 | * file gamma - if it is not 1.0 both RGB_TO_GRAY and COMPOSE need the
|
---|
| 1572 | * tables.
|
---|
| 1573 | */
|
---|
| 1574 | if ((png_ptr->transformations & PNG_GAMMA) != 0 ||
|
---|
| 1575 | ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0 &&
|
---|
| 1576 | (png_gamma_significant(png_ptr->colorspace.gamma) != 0 ||
|
---|
| 1577 | png_gamma_significant(png_ptr->screen_gamma) != 0)) ||
|
---|
| 1578 | ((png_ptr->transformations & PNG_COMPOSE) != 0 &&
|
---|
| 1579 | (png_gamma_significant(png_ptr->colorspace.gamma) != 0 ||
|
---|
| 1580 | png_gamma_significant(png_ptr->screen_gamma) != 0
|
---|
| 1581 | # ifdef PNG_READ_BACKGROUND_SUPPORTED
|
---|
| 1582 | || (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_UNIQUE &&
|
---|
| 1583 | png_gamma_significant(png_ptr->background_gamma) != 0)
|
---|
| 1584 | # endif
|
---|
| 1585 | )) || ((png_ptr->transformations & PNG_ENCODE_ALPHA) != 0 &&
|
---|
| 1586 | png_gamma_significant(png_ptr->screen_gamma) != 0))
|
---|
| 1587 | {
|
---|
| 1588 | png_build_gamma_table(png_ptr, png_ptr->bit_depth);
|
---|
| 1589 |
|
---|
| 1590 | #ifdef PNG_READ_BACKGROUND_SUPPORTED
|
---|
| 1591 | if ((png_ptr->transformations & PNG_COMPOSE) != 0)
|
---|
| 1592 | {
|
---|
| 1593 | /* Issue a warning about this combination: because RGB_TO_GRAY is
|
---|
| 1594 | * optimized to do the gamma transform if present yet do_background has
|
---|
| 1595 | * to do the same thing if both options are set a
|
---|
| 1596 | * double-gamma-correction happens. This is true in all versions of
|
---|
| 1597 | * libpng to date.
|
---|
| 1598 | */
|
---|
| 1599 | if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
|
---|
| 1600 | png_warning(png_ptr,
|
---|
| 1601 | "libpng does not support gamma+background+rgb_to_gray");
|
---|
| 1602 |
|
---|
| 1603 | if ((png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) != 0)
|
---|
| 1604 | {
|
---|
| 1605 | /* We don't get to here unless there is a tRNS chunk with non-opaque
|
---|
| 1606 | * entries - see the checking code at the start of this function.
|
---|
| 1607 | */
|
---|
| 1608 | png_color back, back_1;
|
---|
| 1609 | png_colorp palette = png_ptr->palette;
|
---|
| 1610 | int num_palette = png_ptr->num_palette;
|
---|
| 1611 | int i;
|
---|
| 1612 | if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_FILE)
|
---|
| 1613 | {
|
---|
| 1614 |
|
---|
| 1615 | back.red = png_ptr->gamma_table[png_ptr->background.red];
|
---|
| 1616 | back.green = png_ptr->gamma_table[png_ptr->background.green];
|
---|
| 1617 | back.blue = png_ptr->gamma_table[png_ptr->background.blue];
|
---|
| 1618 |
|
---|
| 1619 | back_1.red = png_ptr->gamma_to_1[png_ptr->background.red];
|
---|
| 1620 | back_1.green = png_ptr->gamma_to_1[png_ptr->background.green];
|
---|
| 1621 | back_1.blue = png_ptr->gamma_to_1[png_ptr->background.blue];
|
---|
| 1622 | }
|
---|
| 1623 | else
|
---|
| 1624 | {
|
---|
| 1625 | png_fixed_point g, gs;
|
---|
| 1626 |
|
---|
| 1627 | switch (png_ptr->background_gamma_type)
|
---|
| 1628 | {
|
---|
| 1629 | case PNG_BACKGROUND_GAMMA_SCREEN:
|
---|
| 1630 | g = (png_ptr->screen_gamma);
|
---|
| 1631 | gs = PNG_FP_1;
|
---|
| 1632 | break;
|
---|
| 1633 |
|
---|
| 1634 | case PNG_BACKGROUND_GAMMA_FILE:
|
---|
| 1635 | g = png_reciprocal(png_ptr->colorspace.gamma);
|
---|
| 1636 | gs = png_reciprocal2(png_ptr->colorspace.gamma,
|
---|
| 1637 | png_ptr->screen_gamma);
|
---|
| 1638 | break;
|
---|
| 1639 |
|
---|
| 1640 | case PNG_BACKGROUND_GAMMA_UNIQUE:
|
---|
| 1641 | g = png_reciprocal(png_ptr->background_gamma);
|
---|
| 1642 | gs = png_reciprocal2(png_ptr->background_gamma,
|
---|
| 1643 | png_ptr->screen_gamma);
|
---|
| 1644 | break;
|
---|
| 1645 | default:
|
---|
| 1646 | g = PNG_FP_1; /* back_1 */
|
---|
| 1647 | gs = PNG_FP_1; /* back */
|
---|
| 1648 | break;
|
---|
| 1649 | }
|
---|
| 1650 |
|
---|
| 1651 | if (png_gamma_significant(gs) != 0)
|
---|
| 1652 | {
|
---|
| 1653 | back.red = png_gamma_8bit_correct(png_ptr->background.red,
|
---|
| 1654 | gs);
|
---|
| 1655 | back.green = png_gamma_8bit_correct(png_ptr->background.green,
|
---|
| 1656 | gs);
|
---|
| 1657 | back.blue = png_gamma_8bit_correct(png_ptr->background.blue,
|
---|
| 1658 | gs);
|
---|
| 1659 | }
|
---|
| 1660 |
|
---|
| 1661 | else
|
---|
| 1662 | {
|
---|
| 1663 | back.red = (png_byte)png_ptr->background.red;
|
---|
| 1664 | back.green = (png_byte)png_ptr->background.green;
|
---|
| 1665 | back.blue = (png_byte)png_ptr->background.blue;
|
---|
| 1666 | }
|
---|
| 1667 |
|
---|
| 1668 | if (png_gamma_significant(g) != 0)
|
---|
| 1669 | {
|
---|
| 1670 | back_1.red = png_gamma_8bit_correct(png_ptr->background.red,
|
---|
| 1671 | g);
|
---|
| 1672 | back_1.green = png_gamma_8bit_correct(
|
---|
| 1673 | png_ptr->background.green, g);
|
---|
| 1674 | back_1.blue = png_gamma_8bit_correct(png_ptr->background.blue,
|
---|
| 1675 | g);
|
---|
| 1676 | }
|
---|
| 1677 |
|
---|
| 1678 | else
|
---|
| 1679 | {
|
---|
| 1680 | back_1.red = (png_byte)png_ptr->background.red;
|
---|
| 1681 | back_1.green = (png_byte)png_ptr->background.green;
|
---|
| 1682 | back_1.blue = (png_byte)png_ptr->background.blue;
|
---|
| 1683 | }
|
---|
| 1684 | }
|
---|
| 1685 |
|
---|
| 1686 | for (i = 0; i < num_palette; i++)
|
---|
| 1687 | {
|
---|
| 1688 | if (i < (int)png_ptr->num_trans &&
|
---|
| 1689 | png_ptr->trans_alpha[i] != 0xff)
|
---|
| 1690 | {
|
---|
| 1691 | if (png_ptr->trans_alpha[i] == 0)
|
---|
| 1692 | {
|
---|
| 1693 | palette[i] = back;
|
---|
| 1694 | }
|
---|
| 1695 | else /* if (png_ptr->trans_alpha[i] != 0xff) */
|
---|
| 1696 | {
|
---|
| 1697 | png_byte v, w;
|
---|
| 1698 |
|
---|
| 1699 | v = png_ptr->gamma_to_1[palette[i].red];
|
---|
| 1700 | png_composite(w, v, png_ptr->trans_alpha[i], back_1.red);
|
---|
| 1701 | palette[i].red = png_ptr->gamma_from_1[w];
|
---|
| 1702 |
|
---|
| 1703 | v = png_ptr->gamma_to_1[palette[i].green];
|
---|
| 1704 | png_composite(w, v, png_ptr->trans_alpha[i], back_1.green);
|
---|
| 1705 | palette[i].green = png_ptr->gamma_from_1[w];
|
---|
| 1706 |
|
---|
| 1707 | v = png_ptr->gamma_to_1[palette[i].blue];
|
---|
| 1708 | png_composite(w, v, png_ptr->trans_alpha[i], back_1.blue);
|
---|
| 1709 | palette[i].blue = png_ptr->gamma_from_1[w];
|
---|
| 1710 | }
|
---|
| 1711 | }
|
---|
| 1712 | else
|
---|
| 1713 | {
|
---|
| 1714 | palette[i].red = png_ptr->gamma_table[palette[i].red];
|
---|
| 1715 | palette[i].green = png_ptr->gamma_table[palette[i].green];
|
---|
| 1716 | palette[i].blue = png_ptr->gamma_table[palette[i].blue];
|
---|
| 1717 | }
|
---|
| 1718 | }
|
---|
| 1719 |
|
---|
| 1720 | /* Prevent the transformations being done again.
|
---|
| 1721 | *
|
---|
| 1722 | * NOTE: this is highly dubious; it removes the transformations in
|
---|
| 1723 | * place. This seems inconsistent with the general treatment of the
|
---|
| 1724 | * transformations elsewhere.
|
---|
| 1725 | */
|
---|
| 1726 | png_ptr->transformations &= ~(PNG_COMPOSE | PNG_GAMMA);
|
---|
| 1727 | } /* color_type == PNG_COLOR_TYPE_PALETTE */
|
---|
| 1728 |
|
---|
| 1729 | /* if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN) */
|
---|
| 1730 | else /* color_type != PNG_COLOR_TYPE_PALETTE */
|
---|
| 1731 | {
|
---|
| 1732 | int gs_sig, g_sig;
|
---|
| 1733 | png_fixed_point g = PNG_FP_1; /* Correction to linear */
|
---|
| 1734 | png_fixed_point gs = PNG_FP_1; /* Correction to screen */
|
---|
| 1735 |
|
---|
| 1736 | switch (png_ptr->background_gamma_type)
|
---|
| 1737 | {
|
---|
| 1738 | case PNG_BACKGROUND_GAMMA_SCREEN:
|
---|
| 1739 | g = png_ptr->screen_gamma;
|
---|
| 1740 | /* gs = PNG_FP_1; */
|
---|
| 1741 | break;
|
---|
| 1742 |
|
---|
| 1743 | case PNG_BACKGROUND_GAMMA_FILE:
|
---|
| 1744 | g = png_reciprocal(png_ptr->colorspace.gamma);
|
---|
| 1745 | gs = png_reciprocal2(png_ptr->colorspace.gamma,
|
---|
| 1746 | png_ptr->screen_gamma);
|
---|
| 1747 | break;
|
---|
| 1748 |
|
---|
| 1749 | case PNG_BACKGROUND_GAMMA_UNIQUE:
|
---|
| 1750 | g = png_reciprocal(png_ptr->background_gamma);
|
---|
| 1751 | gs = png_reciprocal2(png_ptr->background_gamma,
|
---|
| 1752 | png_ptr->screen_gamma);
|
---|
| 1753 | break;
|
---|
| 1754 |
|
---|
| 1755 | default:
|
---|
| 1756 | png_error(png_ptr, "invalid background gamma type");
|
---|
| 1757 | }
|
---|
| 1758 |
|
---|
| 1759 | g_sig = png_gamma_significant(g);
|
---|
| 1760 | gs_sig = png_gamma_significant(gs);
|
---|
| 1761 |
|
---|
| 1762 | if (g_sig != 0)
|
---|
| 1763 | png_ptr->background_1.gray = png_gamma_correct(png_ptr,
|
---|
| 1764 | png_ptr->background.gray, g);
|
---|
| 1765 |
|
---|
| 1766 | if (gs_sig != 0)
|
---|
| 1767 | png_ptr->background.gray = png_gamma_correct(png_ptr,
|
---|
| 1768 | png_ptr->background.gray, gs);
|
---|
| 1769 |
|
---|
| 1770 | if ((png_ptr->background.red != png_ptr->background.green) ||
|
---|
| 1771 | (png_ptr->background.red != png_ptr->background.blue) ||
|
---|
| 1772 | (png_ptr->background.red != png_ptr->background.gray))
|
---|
| 1773 | {
|
---|
| 1774 | /* RGB or RGBA with color background */
|
---|
| 1775 | if (g_sig != 0)
|
---|
| 1776 | {
|
---|
| 1777 | png_ptr->background_1.red = png_gamma_correct(png_ptr,
|
---|
| 1778 | png_ptr->background.red, g);
|
---|
| 1779 |
|
---|
| 1780 | png_ptr->background_1.green = png_gamma_correct(png_ptr,
|
---|
| 1781 | png_ptr->background.green, g);
|
---|
| 1782 |
|
---|
| 1783 | png_ptr->background_1.blue = png_gamma_correct(png_ptr,
|
---|
| 1784 | png_ptr->background.blue, g);
|
---|
| 1785 | }
|
---|
| 1786 |
|
---|
| 1787 | if (gs_sig != 0)
|
---|
| 1788 | {
|
---|
| 1789 | png_ptr->background.red = png_gamma_correct(png_ptr,
|
---|
| 1790 | png_ptr->background.red, gs);
|
---|
| 1791 |
|
---|
| 1792 | png_ptr->background.green = png_gamma_correct(png_ptr,
|
---|
| 1793 | png_ptr->background.green, gs);
|
---|
| 1794 |
|
---|
| 1795 | png_ptr->background.blue = png_gamma_correct(png_ptr,
|
---|
| 1796 | png_ptr->background.blue, gs);
|
---|
| 1797 | }
|
---|
| 1798 | }
|
---|
| 1799 |
|
---|
| 1800 | else
|
---|
| 1801 | {
|
---|
| 1802 | /* GRAY, GRAY ALPHA, RGB, or RGBA with gray background */
|
---|
| 1803 | png_ptr->background_1.red = png_ptr->background_1.green
|
---|
| 1804 | = png_ptr->background_1.blue = png_ptr->background_1.gray;
|
---|
| 1805 |
|
---|
| 1806 | png_ptr->background.red = png_ptr->background.green
|
---|
| 1807 | = png_ptr->background.blue = png_ptr->background.gray;
|
---|
| 1808 | }
|
---|
| 1809 |
|
---|
| 1810 | /* The background is now in screen gamma: */
|
---|
| 1811 | png_ptr->background_gamma_type = PNG_BACKGROUND_GAMMA_SCREEN;
|
---|
| 1812 | } /* color_type != PNG_COLOR_TYPE_PALETTE */
|
---|
| 1813 | }/* png_ptr->transformations & PNG_BACKGROUND */
|
---|
| 1814 |
|
---|
| 1815 | else
|
---|
| 1816 | /* Transformation does not include PNG_BACKGROUND */
|
---|
| 1817 | #endif /* READ_BACKGROUND */
|
---|
| 1818 | if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE
|
---|
| 1819 | #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
|
---|
| 1820 | /* RGB_TO_GRAY needs to have non-gamma-corrected values! */
|
---|
| 1821 | && ((png_ptr->transformations & PNG_EXPAND) == 0 ||
|
---|
| 1822 | (png_ptr->transformations & PNG_RGB_TO_GRAY) == 0)
|
---|
| 1823 | #endif
|
---|
| 1824 | )
|
---|
| 1825 | {
|
---|
| 1826 | png_colorp palette = png_ptr->palette;
|
---|
| 1827 | int num_palette = png_ptr->num_palette;
|
---|
| 1828 | int i;
|
---|
| 1829 |
|
---|
| 1830 | /* NOTE: there are other transformations that should probably be in
|
---|
| 1831 | * here too.
|
---|
| 1832 | */
|
---|
| 1833 | for (i = 0; i < num_palette; i++)
|
---|
| 1834 | {
|
---|
| 1835 | palette[i].red = png_ptr->gamma_table[palette[i].red];
|
---|
| 1836 | palette[i].green = png_ptr->gamma_table[palette[i].green];
|
---|
| 1837 | palette[i].blue = png_ptr->gamma_table[palette[i].blue];
|
---|
| 1838 | }
|
---|
| 1839 |
|
---|
| 1840 | /* Done the gamma correction. */
|
---|
| 1841 | png_ptr->transformations &= ~PNG_GAMMA;
|
---|
| 1842 | } /* color_type == PALETTE && !PNG_BACKGROUND transformation */
|
---|
| 1843 | }
|
---|
| 1844 | #ifdef PNG_READ_BACKGROUND_SUPPORTED
|
---|
| 1845 | else
|
---|
| 1846 | #endif
|
---|
| 1847 | #endif /* READ_GAMMA */
|
---|
| 1848 |
|
---|
| 1849 | #ifdef PNG_READ_BACKGROUND_SUPPORTED
|
---|
| 1850 | /* No GAMMA transformation (see the hanging else 4 lines above) */
|
---|
| 1851 | if ((png_ptr->transformations & PNG_COMPOSE) != 0 &&
|
---|
| 1852 | (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
|
---|
| 1853 | {
|
---|
| 1854 | int i;
|
---|
| 1855 | int istop = (int)png_ptr->num_trans;
|
---|
| 1856 | png_color back;
|
---|
| 1857 | png_colorp palette = png_ptr->palette;
|
---|
| 1858 |
|
---|
| 1859 | back.red = (png_byte)png_ptr->background.red;
|
---|
| 1860 | back.green = (png_byte)png_ptr->background.green;
|
---|
| 1861 | back.blue = (png_byte)png_ptr->background.blue;
|
---|
| 1862 |
|
---|
| 1863 | for (i = 0; i < istop; i++)
|
---|
| 1864 | {
|
---|
| 1865 | if (png_ptr->trans_alpha[i] == 0)
|
---|
| 1866 | {
|
---|
| 1867 | palette[i] = back;
|
---|
| 1868 | }
|
---|
| 1869 |
|
---|
| 1870 | else if (png_ptr->trans_alpha[i] != 0xff)
|
---|
| 1871 | {
|
---|
| 1872 | /* The png_composite() macro is defined in png.h */
|
---|
| 1873 | png_composite(palette[i].red, palette[i].red,
|
---|
| 1874 | png_ptr->trans_alpha[i], back.red);
|
---|
| 1875 |
|
---|
| 1876 | png_composite(palette[i].green, palette[i].green,
|
---|
| 1877 | png_ptr->trans_alpha[i], back.green);
|
---|
| 1878 |
|
---|
| 1879 | png_composite(palette[i].blue, palette[i].blue,
|
---|
| 1880 | png_ptr->trans_alpha[i], back.blue);
|
---|
| 1881 | }
|
---|
| 1882 | }
|
---|
| 1883 |
|
---|
| 1884 | png_ptr->transformations &= ~PNG_COMPOSE;
|
---|
| 1885 | }
|
---|
| 1886 | #endif /* READ_BACKGROUND */
|
---|
| 1887 |
|
---|
| 1888 | #ifdef PNG_READ_SHIFT_SUPPORTED
|
---|
| 1889 | if ((png_ptr->transformations & PNG_SHIFT) != 0 &&
|
---|
| 1890 | (png_ptr->transformations & PNG_EXPAND) == 0 &&
|
---|
| 1891 | (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
|
---|
| 1892 | {
|
---|
| 1893 | int i;
|
---|
| 1894 | int istop = png_ptr->num_palette;
|
---|
| 1895 | int shift = 8 - png_ptr->sig_bit.red;
|
---|
| 1896 |
|
---|
| 1897 | png_ptr->transformations &= ~PNG_SHIFT;
|
---|
| 1898 |
|
---|
| 1899 | /* significant bits can be in the range 1 to 7 for a meaningful result, if
|
---|
| 1900 | * the number of significant bits is 0 then no shift is done (this is an
|
---|
| 1901 | * error condition which is silently ignored.)
|
---|
| 1902 | */
|
---|
| 1903 | if (shift > 0 && shift < 8)
|
---|
| 1904 | for (i=0; i<istop; ++i)
|
---|
| 1905 | {
|
---|
| 1906 | int component = png_ptr->palette[i].red;
|
---|
| 1907 |
|
---|
| 1908 | component >>= shift;
|
---|
| 1909 | png_ptr->palette[i].red = (png_byte)component;
|
---|
| 1910 | }
|
---|
| 1911 |
|
---|
| 1912 | shift = 8 - png_ptr->sig_bit.green;
|
---|
| 1913 | if (shift > 0 && shift < 8)
|
---|
| 1914 | for (i=0; i<istop; ++i)
|
---|
| 1915 | {
|
---|
| 1916 | int component = png_ptr->palette[i].green;
|
---|
| 1917 |
|
---|
| 1918 | component >>= shift;
|
---|
| 1919 | png_ptr->palette[i].green = (png_byte)component;
|
---|
| 1920 | }
|
---|
| 1921 |
|
---|
| 1922 | shift = 8 - png_ptr->sig_bit.blue;
|
---|
| 1923 | if (shift > 0 && shift < 8)
|
---|
| 1924 | for (i=0; i<istop; ++i)
|
---|
| 1925 | {
|
---|
| 1926 | int component = png_ptr->palette[i].blue;
|
---|
| 1927 |
|
---|
| 1928 | component >>= shift;
|
---|
| 1929 | png_ptr->palette[i].blue = (png_byte)component;
|
---|
| 1930 | }
|
---|
| 1931 | }
|
---|
| 1932 | #endif /* READ_SHIFT */
|
---|
| 1933 | }
|
---|
| 1934 |
|
---|
| 1935 | /* Modify the info structure to reflect the transformations. The
|
---|
| 1936 | * info should be updated so a PNG file could be written with it,
|
---|
| 1937 | * assuming the transformations result in valid PNG data.
|
---|
| 1938 | */
|
---|
| 1939 | void /* PRIVATE */
|
---|
| 1940 | png_read_transform_info(png_structrp png_ptr, png_inforp info_ptr)
|
---|
| 1941 | {
|
---|
| 1942 | png_debug(1, "in png_read_transform_info");
|
---|
| 1943 |
|
---|
| 1944 | #ifdef PNG_READ_EXPAND_SUPPORTED
|
---|
| 1945 | if ((png_ptr->transformations & PNG_EXPAND) != 0)
|
---|
| 1946 | {
|
---|
| 1947 | if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
|
---|
| 1948 | {
|
---|
| 1949 | /* This check must match what actually happens in
|
---|
| 1950 | * png_do_expand_palette; if it ever checks the tRNS chunk to see if
|
---|
| 1951 | * it is all opaque we must do the same (at present it does not.)
|
---|
| 1952 | */
|
---|
| 1953 | if (png_ptr->num_trans > 0)
|
---|
| 1954 | info_ptr->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
|
---|
| 1955 |
|
---|
| 1956 | else
|
---|
| 1957 | info_ptr->color_type = PNG_COLOR_TYPE_RGB;
|
---|
| 1958 |
|
---|
| 1959 | info_ptr->bit_depth = 8;
|
---|
| 1960 | info_ptr->num_trans = 0;
|
---|
| 1961 |
|
---|
| 1962 | if (png_ptr->palette == NULL)
|
---|
| 1963 | png_error (png_ptr, "Palette is NULL in indexed image");
|
---|
| 1964 | }
|
---|
| 1965 | else
|
---|
| 1966 | {
|
---|
| 1967 | if (png_ptr->num_trans != 0)
|
---|
| 1968 | {
|
---|
| 1969 | if ((png_ptr->transformations & PNG_EXPAND_tRNS) != 0)
|
---|
| 1970 | info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
|
---|
| 1971 | }
|
---|
| 1972 | if (info_ptr->bit_depth < 8)
|
---|
| 1973 | info_ptr->bit_depth = 8;
|
---|
| 1974 |
|
---|
| 1975 | info_ptr->num_trans = 0;
|
---|
| 1976 | }
|
---|
| 1977 | }
|
---|
| 1978 | #endif
|
---|
| 1979 |
|
---|
| 1980 | #if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
|
---|
| 1981 | defined(PNG_READ_ALPHA_MODE_SUPPORTED)
|
---|
| 1982 | /* The following is almost certainly wrong unless the background value is in
|
---|
| 1983 | * the screen space!
|
---|
| 1984 | */
|
---|
| 1985 | if ((png_ptr->transformations & PNG_COMPOSE) != 0)
|
---|
| 1986 | info_ptr->background = png_ptr->background;
|
---|
| 1987 | #endif
|
---|
| 1988 |
|
---|
| 1989 | #ifdef PNG_READ_GAMMA_SUPPORTED
|
---|
| 1990 | /* The following used to be conditional on PNG_GAMMA (prior to 1.5.4),
|
---|
| 1991 | * however it seems that the code in png_init_read_transformations, which has
|
---|
| 1992 | * been called before this from png_read_update_info->png_read_start_row
|
---|
| 1993 | * sometimes does the gamma transform and cancels the flag.
|
---|
| 1994 | *
|
---|
| 1995 | * TODO: this looks wrong; the info_ptr should end up with a gamma equal to
|
---|
| 1996 | * the screen_gamma value. The following probably results in weirdness if
|
---|
| 1997 | * the info_ptr is used by the app after the rows have been read.
|
---|
| 1998 | */
|
---|
| 1999 | info_ptr->colorspace.gamma = png_ptr->colorspace.gamma;
|
---|
| 2000 | #endif
|
---|
| 2001 |
|
---|
| 2002 | if (info_ptr->bit_depth == 16)
|
---|
| 2003 | {
|
---|
| 2004 | # ifdef PNG_READ_16BIT_SUPPORTED
|
---|
| 2005 | # ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
|
---|
| 2006 | if ((png_ptr->transformations & PNG_SCALE_16_TO_8) != 0)
|
---|
| 2007 | info_ptr->bit_depth = 8;
|
---|
| 2008 | # endif
|
---|
| 2009 |
|
---|
| 2010 | # ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
|
---|
| 2011 | if ((png_ptr->transformations & PNG_16_TO_8) != 0)
|
---|
| 2012 | info_ptr->bit_depth = 8;
|
---|
| 2013 | # endif
|
---|
| 2014 |
|
---|
| 2015 | # else
|
---|
| 2016 | /* No 16-bit support: force chopping 16-bit input down to 8, in this case
|
---|
| 2017 | * the app program can chose if both APIs are available by setting the
|
---|
| 2018 | * correct scaling to use.
|
---|
| 2019 | */
|
---|
| 2020 | # ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
|
---|
| 2021 | /* For compatibility with previous versions use the strip method by
|
---|
| 2022 | * default. This code works because if PNG_SCALE_16_TO_8 is already
|
---|
| 2023 | * set the code below will do that in preference to the chop.
|
---|
| 2024 | */
|
---|
| 2025 | png_ptr->transformations |= PNG_16_TO_8;
|
---|
| 2026 | info_ptr->bit_depth = 8;
|
---|
| 2027 | # else
|
---|
| 2028 |
|
---|
| 2029 | # ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
|
---|
| 2030 | png_ptr->transformations |= PNG_SCALE_16_TO_8;
|
---|
| 2031 | info_ptr->bit_depth = 8;
|
---|
| 2032 | # else
|
---|
| 2033 |
|
---|
| 2034 | CONFIGURATION ERROR: you must enable at least one 16 to 8 method
|
---|
| 2035 | # endif
|
---|
| 2036 | # endif
|
---|
| 2037 | #endif /* !READ_16BIT */
|
---|
| 2038 | }
|
---|
| 2039 |
|
---|
| 2040 | #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
|
---|
| 2041 | if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0)
|
---|
| 2042 | info_ptr->color_type = (png_byte)(info_ptr->color_type |
|
---|
| 2043 | PNG_COLOR_MASK_COLOR);
|
---|
| 2044 | #endif
|
---|
| 2045 |
|
---|
| 2046 | #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
|
---|
| 2047 | if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
|
---|
| 2048 | info_ptr->color_type = (png_byte)(info_ptr->color_type &
|
---|
| 2049 | ~PNG_COLOR_MASK_COLOR);
|
---|
| 2050 | #endif
|
---|
| 2051 |
|
---|
| 2052 | #ifdef PNG_READ_QUANTIZE_SUPPORTED
|
---|
| 2053 | if ((png_ptr->transformations & PNG_QUANTIZE) != 0)
|
---|
| 2054 | {
|
---|
| 2055 | if (((info_ptr->color_type == PNG_COLOR_TYPE_RGB) ||
|
---|
| 2056 | (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)) &&
|
---|
| 2057 | png_ptr->palette_lookup != 0 && info_ptr->bit_depth == 8)
|
---|
| 2058 | {
|
---|
| 2059 | info_ptr->color_type = PNG_COLOR_TYPE_PALETTE;
|
---|
| 2060 | }
|
---|
| 2061 | }
|
---|
| 2062 | #endif
|
---|
| 2063 |
|
---|
| 2064 | #ifdef PNG_READ_EXPAND_16_SUPPORTED
|
---|
| 2065 | if ((png_ptr->transformations & PNG_EXPAND_16) != 0 &&
|
---|
| 2066 | info_ptr->bit_depth == 8 &&
|
---|
| 2067 | info_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
|
---|
| 2068 | {
|
---|
| 2069 | info_ptr->bit_depth = 16;
|
---|
| 2070 | }
|
---|
| 2071 | #endif
|
---|
| 2072 |
|
---|
| 2073 | #ifdef PNG_READ_PACK_SUPPORTED
|
---|
| 2074 | if ((png_ptr->transformations & PNG_PACK) != 0 &&
|
---|
| 2075 | (info_ptr->bit_depth < 8))
|
---|
| 2076 | info_ptr->bit_depth = 8;
|
---|
| 2077 | #endif
|
---|
| 2078 |
|
---|
| 2079 | if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
|
---|
| 2080 | info_ptr->channels = 1;
|
---|
| 2081 |
|
---|
| 2082 | else if ((info_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
|
---|
| 2083 | info_ptr->channels = 3;
|
---|
| 2084 |
|
---|
| 2085 | else
|
---|
| 2086 | info_ptr->channels = 1;
|
---|
| 2087 |
|
---|
| 2088 | #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
|
---|
| 2089 | if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0)
|
---|
| 2090 | {
|
---|
| 2091 | info_ptr->color_type = (png_byte)(info_ptr->color_type &
|
---|
| 2092 | ~PNG_COLOR_MASK_ALPHA);
|
---|
| 2093 | info_ptr->num_trans = 0;
|
---|
| 2094 | }
|
---|
| 2095 | #endif
|
---|
| 2096 |
|
---|
| 2097 | if ((info_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
|
---|
| 2098 | info_ptr->channels++;
|
---|
| 2099 |
|
---|
| 2100 | #ifdef PNG_READ_FILLER_SUPPORTED
|
---|
| 2101 | /* STRIP_ALPHA and FILLER allowed: MASK_ALPHA bit stripped above */
|
---|
| 2102 | if ((png_ptr->transformations & PNG_FILLER) != 0 &&
|
---|
| 2103 | (info_ptr->color_type == PNG_COLOR_TYPE_RGB ||
|
---|
| 2104 | info_ptr->color_type == PNG_COLOR_TYPE_GRAY))
|
---|
| 2105 | {
|
---|
| 2106 | info_ptr->channels++;
|
---|
| 2107 | /* If adding a true alpha channel not just filler */
|
---|
| 2108 | if ((png_ptr->transformations & PNG_ADD_ALPHA) != 0)
|
---|
| 2109 | info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
|
---|
| 2110 | }
|
---|
| 2111 | #endif
|
---|
| 2112 |
|
---|
| 2113 | #if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) && \
|
---|
| 2114 | defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
|
---|
| 2115 | if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
|
---|
| 2116 | {
|
---|
| 2117 | if (png_ptr->user_transform_depth != 0)
|
---|
| 2118 | info_ptr->bit_depth = png_ptr->user_transform_depth;
|
---|
| 2119 |
|
---|
| 2120 | if (png_ptr->user_transform_channels != 0)
|
---|
| 2121 | info_ptr->channels = png_ptr->user_transform_channels;
|
---|
| 2122 | }
|
---|
| 2123 | #endif
|
---|
| 2124 |
|
---|
| 2125 | info_ptr->pixel_depth = (png_byte)(info_ptr->channels *
|
---|
| 2126 | info_ptr->bit_depth);
|
---|
| 2127 |
|
---|
| 2128 | info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth, info_ptr->width);
|
---|
| 2129 |
|
---|
| 2130 | /* Adding in 1.5.4: cache the above value in png_struct so that we can later
|
---|
| 2131 | * check in png_rowbytes that the user buffer won't get overwritten. Note
|
---|
| 2132 | * that the field is not always set - if png_read_update_info isn't called
|
---|
| 2133 | * the application has to either not do any transforms or get the calculation
|
---|
| 2134 | * right itself.
|
---|
| 2135 | */
|
---|
| 2136 | png_ptr->info_rowbytes = info_ptr->rowbytes;
|
---|
| 2137 |
|
---|
| 2138 | #ifndef PNG_READ_EXPAND_SUPPORTED
|
---|
| 2139 | if (png_ptr != NULL)
|
---|
| 2140 | return;
|
---|
| 2141 | #endif
|
---|
| 2142 | }
|
---|
| 2143 |
|
---|
| 2144 | #ifdef PNG_READ_PACK_SUPPORTED
|
---|
| 2145 | /* Unpack pixels of 1, 2, or 4 bits per pixel into 1 byte per pixel,
|
---|
| 2146 | * without changing the actual values. Thus, if you had a row with
|
---|
| 2147 | * a bit depth of 1, you would end up with bytes that only contained
|
---|
| 2148 | * the numbers 0 or 1. If you would rather they contain 0 and 255, use
|
---|
| 2149 | * png_do_shift() after this.
|
---|
| 2150 | */
|
---|
| 2151 | static void
|
---|
| 2152 | png_do_unpack(png_row_infop row_info, png_bytep row)
|
---|
| 2153 | {
|
---|
| 2154 | png_debug(1, "in png_do_unpack");
|
---|
| 2155 |
|
---|
| 2156 | if (row_info->bit_depth < 8)
|
---|
| 2157 | {
|
---|
| 2158 | png_uint_32 i;
|
---|
| 2159 | png_uint_32 row_width=row_info->width;
|
---|
| 2160 |
|
---|
| 2161 | switch (row_info->bit_depth)
|
---|
| 2162 | {
|
---|
| 2163 | case 1:
|
---|
| 2164 | {
|
---|
| 2165 | png_bytep sp = row + (size_t)((row_width - 1) >> 3);
|
---|
| 2166 | png_bytep dp = row + (size_t)row_width - 1;
|
---|
| 2167 | png_uint_32 shift = 7U - ((row_width + 7U) & 0x07);
|
---|
| 2168 | for (i = 0; i < row_width; i++)
|
---|
| 2169 | {
|
---|
| 2170 | *dp = (png_byte)((*sp >> shift) & 0x01);
|
---|
| 2171 |
|
---|
| 2172 | if (shift == 7)
|
---|
| 2173 | {
|
---|
| 2174 | shift = 0;
|
---|
| 2175 | sp--;
|
---|
| 2176 | }
|
---|
| 2177 |
|
---|
| 2178 | else
|
---|
| 2179 | shift++;
|
---|
| 2180 |
|
---|
| 2181 | dp--;
|
---|
| 2182 | }
|
---|
| 2183 | break;
|
---|
| 2184 | }
|
---|
| 2185 |
|
---|
| 2186 | case 2:
|
---|
| 2187 | {
|
---|
| 2188 |
|
---|
| 2189 | png_bytep sp = row + (size_t)((row_width - 1) >> 2);
|
---|
| 2190 | png_bytep dp = row + (size_t)row_width - 1;
|
---|
| 2191 | png_uint_32 shift = ((3U - ((row_width + 3U) & 0x03)) << 1);
|
---|
| 2192 | for (i = 0; i < row_width; i++)
|
---|
| 2193 | {
|
---|
| 2194 | *dp = (png_byte)((*sp >> shift) & 0x03);
|
---|
| 2195 |
|
---|
| 2196 | if (shift == 6)
|
---|
| 2197 | {
|
---|
| 2198 | shift = 0;
|
---|
| 2199 | sp--;
|
---|
| 2200 | }
|
---|
| 2201 |
|
---|
| 2202 | else
|
---|
| 2203 | shift += 2;
|
---|
| 2204 |
|
---|
| 2205 | dp--;
|
---|
| 2206 | }
|
---|
| 2207 | break;
|
---|
| 2208 | }
|
---|
| 2209 |
|
---|
| 2210 | case 4:
|
---|
| 2211 | {
|
---|
| 2212 | png_bytep sp = row + (size_t)((row_width - 1) >> 1);
|
---|
| 2213 | png_bytep dp = row + (size_t)row_width - 1;
|
---|
| 2214 | png_uint_32 shift = ((1U - ((row_width + 1U) & 0x01)) << 2);
|
---|
| 2215 | for (i = 0; i < row_width; i++)
|
---|
| 2216 | {
|
---|
| 2217 | *dp = (png_byte)((*sp >> shift) & 0x0f);
|
---|
| 2218 |
|
---|
| 2219 | if (shift == 4)
|
---|
| 2220 | {
|
---|
| 2221 | shift = 0;
|
---|
| 2222 | sp--;
|
---|
| 2223 | }
|
---|
| 2224 |
|
---|
| 2225 | else
|
---|
| 2226 | shift = 4;
|
---|
| 2227 |
|
---|
| 2228 | dp--;
|
---|
| 2229 | }
|
---|
| 2230 | break;
|
---|
| 2231 | }
|
---|
| 2232 |
|
---|
| 2233 | default:
|
---|
| 2234 | break;
|
---|
| 2235 | }
|
---|
| 2236 | row_info->bit_depth = 8;
|
---|
| 2237 | row_info->pixel_depth = (png_byte)(8 * row_info->channels);
|
---|
| 2238 | row_info->rowbytes = row_width * row_info->channels;
|
---|
| 2239 | }
|
---|
| 2240 | }
|
---|
| 2241 | #endif
|
---|
| 2242 |
|
---|
| 2243 | #ifdef PNG_READ_SHIFT_SUPPORTED
|
---|
| 2244 | /* Reverse the effects of png_do_shift. This routine merely shifts the
|
---|
| 2245 | * pixels back to their significant bits values. Thus, if you have
|
---|
| 2246 | * a row of bit depth 8, but only 5 are significant, this will shift
|
---|
| 2247 | * the values back to 0 through 31.
|
---|
| 2248 | */
|
---|
| 2249 | static void
|
---|
| 2250 | png_do_unshift(png_row_infop row_info, png_bytep row,
|
---|
| 2251 | png_const_color_8p sig_bits)
|
---|
| 2252 | {
|
---|
| 2253 | int color_type;
|
---|
| 2254 |
|
---|
| 2255 | png_debug(1, "in png_do_unshift");
|
---|
| 2256 |
|
---|
| 2257 | /* The palette case has already been handled in the _init routine. */
|
---|
| 2258 | color_type = row_info->color_type;
|
---|
| 2259 |
|
---|
| 2260 | if (color_type != PNG_COLOR_TYPE_PALETTE)
|
---|
| 2261 | {
|
---|
| 2262 | int shift[4];
|
---|
| 2263 | int channels = 0;
|
---|
| 2264 | int bit_depth = row_info->bit_depth;
|
---|
| 2265 |
|
---|
| 2266 | if ((color_type & PNG_COLOR_MASK_COLOR) != 0)
|
---|
| 2267 | {
|
---|
| 2268 | shift[channels++] = bit_depth - sig_bits->red;
|
---|
| 2269 | shift[channels++] = bit_depth - sig_bits->green;
|
---|
| 2270 | shift[channels++] = bit_depth - sig_bits->blue;
|
---|
| 2271 | }
|
---|
| 2272 |
|
---|
| 2273 | else
|
---|
| 2274 | {
|
---|
| 2275 | shift[channels++] = bit_depth - sig_bits->gray;
|
---|
| 2276 | }
|
---|
| 2277 |
|
---|
| 2278 | if ((color_type & PNG_COLOR_MASK_ALPHA) != 0)
|
---|
| 2279 | {
|
---|
| 2280 | shift[channels++] = bit_depth - sig_bits->alpha;
|
---|
| 2281 | }
|
---|
| 2282 |
|
---|
| 2283 | {
|
---|
| 2284 | int c, have_shift;
|
---|
| 2285 |
|
---|
| 2286 | for (c = have_shift = 0; c < channels; ++c)
|
---|
| 2287 | {
|
---|
| 2288 | /* A shift of more than the bit depth is an error condition but it
|
---|
| 2289 | * gets ignored here.
|
---|
| 2290 | */
|
---|
| 2291 | if (shift[c] <= 0 || shift[c] >= bit_depth)
|
---|
| 2292 | shift[c] = 0;
|
---|
| 2293 |
|
---|
| 2294 | else
|
---|
| 2295 | have_shift = 1;
|
---|
| 2296 | }
|
---|
| 2297 |
|
---|
| 2298 | if (have_shift == 0)
|
---|
| 2299 | return;
|
---|
| 2300 | }
|
---|
| 2301 |
|
---|
| 2302 | switch (bit_depth)
|
---|
| 2303 | {
|
---|
| 2304 | default:
|
---|
| 2305 | /* Must be 1bpp gray: should not be here! */
|
---|
| 2306 | /* NOTREACHED */
|
---|
| 2307 | break;
|
---|
| 2308 |
|
---|
| 2309 | case 2:
|
---|
| 2310 | /* Must be 2bpp gray */
|
---|
| 2311 | /* assert(channels == 1 && shift[0] == 1) */
|
---|
| 2312 | {
|
---|
| 2313 | png_bytep bp = row;
|
---|
| 2314 | png_bytep bp_end = bp + row_info->rowbytes;
|
---|
| 2315 |
|
---|
| 2316 | while (bp < bp_end)
|
---|
| 2317 | {
|
---|
| 2318 | int b = (*bp >> 1) & 0x55;
|
---|
| 2319 | *bp++ = (png_byte)b;
|
---|
| 2320 | }
|
---|
| 2321 | break;
|
---|
| 2322 | }
|
---|
| 2323 |
|
---|
| 2324 | case 4:
|
---|
| 2325 | /* Must be 4bpp gray */
|
---|
| 2326 | /* assert(channels == 1) */
|
---|
| 2327 | {
|
---|
| 2328 | png_bytep bp = row;
|
---|
| 2329 | png_bytep bp_end = bp + row_info->rowbytes;
|
---|
| 2330 | int gray_shift = shift[0];
|
---|
| 2331 | int mask = 0xf >> gray_shift;
|
---|
| 2332 |
|
---|
| 2333 | mask |= mask << 4;
|
---|
| 2334 |
|
---|
| 2335 | while (bp < bp_end)
|
---|
| 2336 | {
|
---|
| 2337 | int b = (*bp >> gray_shift) & mask;
|
---|
| 2338 | *bp++ = (png_byte)b;
|
---|
| 2339 | }
|
---|
| 2340 | break;
|
---|
| 2341 | }
|
---|
| 2342 |
|
---|
| 2343 | case 8:
|
---|
| 2344 | /* Single byte components, G, GA, RGB, RGBA */
|
---|
| 2345 | {
|
---|
| 2346 | png_bytep bp = row;
|
---|
| 2347 | png_bytep bp_end = bp + row_info->rowbytes;
|
---|
| 2348 | int channel = 0;
|
---|
| 2349 |
|
---|
| 2350 | while (bp < bp_end)
|
---|
| 2351 | {
|
---|
| 2352 | int b = *bp >> shift[channel];
|
---|
| 2353 | if (++channel >= channels)
|
---|
| 2354 | channel = 0;
|
---|
| 2355 | *bp++ = (png_byte)b;
|
---|
| 2356 | }
|
---|
| 2357 | break;
|
---|
| 2358 | }
|
---|
| 2359 |
|
---|
| 2360 | #ifdef PNG_READ_16BIT_SUPPORTED
|
---|
| 2361 | case 16:
|
---|
| 2362 | /* Double byte components, G, GA, RGB, RGBA */
|
---|
| 2363 | {
|
---|
| 2364 | png_bytep bp = row;
|
---|
| 2365 | png_bytep bp_end = bp + row_info->rowbytes;
|
---|
| 2366 | int channel = 0;
|
---|
| 2367 |
|
---|
| 2368 | while (bp < bp_end)
|
---|
| 2369 | {
|
---|
| 2370 | int value = (bp[0] << 8) + bp[1];
|
---|
| 2371 |
|
---|
| 2372 | value >>= shift[channel];
|
---|
| 2373 | if (++channel >= channels)
|
---|
| 2374 | channel = 0;
|
---|
| 2375 | *bp++ = (png_byte)(value >> 8);
|
---|
| 2376 | *bp++ = (png_byte)value;
|
---|
| 2377 | }
|
---|
| 2378 | break;
|
---|
| 2379 | }
|
---|
| 2380 | #endif
|
---|
| 2381 | }
|
---|
| 2382 | }
|
---|
| 2383 | }
|
---|
| 2384 | #endif
|
---|
| 2385 |
|
---|
| 2386 | #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
|
---|
| 2387 | /* Scale rows of bit depth 16 down to 8 accurately */
|
---|
| 2388 | static void
|
---|
| 2389 | png_do_scale_16_to_8(png_row_infop row_info, png_bytep row)
|
---|
| 2390 | {
|
---|
| 2391 | png_debug(1, "in png_do_scale_16_to_8");
|
---|
| 2392 |
|
---|
| 2393 | if (row_info->bit_depth == 16)
|
---|
| 2394 | {
|
---|
| 2395 | png_bytep sp = row; /* source */
|
---|
| 2396 | png_bytep dp = row; /* destination */
|
---|
| 2397 | png_bytep ep = sp + row_info->rowbytes; /* end+1 */
|
---|
| 2398 |
|
---|
| 2399 | while (sp < ep)
|
---|
| 2400 | {
|
---|
| 2401 | /* The input is an array of 16-bit components, these must be scaled to
|
---|
| 2402 | * 8 bits each. For a 16-bit value V the required value (from the PNG
|
---|
| 2403 | * specification) is:
|
---|
| 2404 | *
|
---|
| 2405 | * (V * 255) / 65535
|
---|
| 2406 | *
|
---|
| 2407 | * This reduces to round(V / 257), or floor((V + 128.5)/257)
|
---|
| 2408 | *
|
---|
| 2409 | * Represent V as the two byte value vhi.vlo. Make a guess that the
|
---|
| 2410 | * result is the top byte of V, vhi, then the correction to this value
|
---|
| 2411 | * is:
|
---|
| 2412 | *
|
---|
| 2413 | * error = floor(((V-vhi.vhi) + 128.5) / 257)
|
---|
| 2414 | * = floor(((vlo-vhi) + 128.5) / 257)
|
---|
| 2415 | *
|
---|
| 2416 | * This can be approximated using integer arithmetic (and a signed
|
---|
| 2417 | * shift):
|
---|
| 2418 | *
|
---|
| 2419 | * error = (vlo-vhi+128) >> 8;
|
---|
| 2420 | *
|
---|
| 2421 | * The approximate differs from the exact answer only when (vlo-vhi) is
|
---|
| 2422 | * 128; it then gives a correction of +1 when the exact correction is
|
---|
| 2423 | * 0. This gives 128 errors. The exact answer (correct for all 16-bit
|
---|
| 2424 | * input values) is:
|
---|
| 2425 | *
|
---|
| 2426 | * error = (vlo-vhi+128)*65535 >> 24;
|
---|
| 2427 | *
|
---|
| 2428 | * An alternative arithmetic calculation which also gives no errors is:
|
---|
| 2429 | *
|
---|
| 2430 | * (V * 255 + 32895) >> 16
|
---|
| 2431 | */
|
---|
| 2432 |
|
---|
| 2433 | png_int_32 tmp = *sp++; /* must be signed! */
|
---|
| 2434 | tmp += (((int)*sp++ - tmp + 128) * 65535) >> 24;
|
---|
| 2435 | *dp++ = (png_byte)tmp;
|
---|
| 2436 | }
|
---|
| 2437 |
|
---|
| 2438 | row_info->bit_depth = 8;
|
---|
| 2439 | row_info->pixel_depth = (png_byte)(8 * row_info->channels);
|
---|
| 2440 | row_info->rowbytes = row_info->width * row_info->channels;
|
---|
| 2441 | }
|
---|
| 2442 | }
|
---|
| 2443 | #endif
|
---|
| 2444 |
|
---|
| 2445 | #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
|
---|
| 2446 | static void
|
---|
| 2447 | /* Simply discard the low byte. This was the default behavior prior
|
---|
| 2448 | * to libpng-1.5.4.
|
---|
| 2449 | */
|
---|
| 2450 | png_do_chop(png_row_infop row_info, png_bytep row)
|
---|
| 2451 | {
|
---|
| 2452 | png_debug(1, "in png_do_chop");
|
---|
| 2453 |
|
---|
| 2454 | if (row_info->bit_depth == 16)
|
---|
| 2455 | {
|
---|
| 2456 | png_bytep sp = row; /* source */
|
---|
| 2457 | png_bytep dp = row; /* destination */
|
---|
| 2458 | png_bytep ep = sp + row_info->rowbytes; /* end+1 */
|
---|
| 2459 |
|
---|
| 2460 | while (sp < ep)
|
---|
| 2461 | {
|
---|
| 2462 | *dp++ = *sp;
|
---|
| 2463 | sp += 2; /* skip low byte */
|
---|
| 2464 | }
|
---|
| 2465 |
|
---|
| 2466 | row_info->bit_depth = 8;
|
---|
| 2467 | row_info->pixel_depth = (png_byte)(8 * row_info->channels);
|
---|
| 2468 | row_info->rowbytes = row_info->width * row_info->channels;
|
---|
| 2469 | }
|
---|
| 2470 | }
|
---|
| 2471 | #endif
|
---|
| 2472 |
|
---|
| 2473 | #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
|
---|
| 2474 | static void
|
---|
| 2475 | png_do_read_swap_alpha(png_row_infop row_info, png_bytep row)
|
---|
| 2476 | {
|
---|
| 2477 | png_uint_32 row_width = row_info->width;
|
---|
| 2478 |
|
---|
| 2479 | png_debug(1, "in png_do_read_swap_alpha");
|
---|
| 2480 |
|
---|
| 2481 | if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
|
---|
| 2482 | {
|
---|
| 2483 | /* This converts from RGBA to ARGB */
|
---|
| 2484 | if (row_info->bit_depth == 8)
|
---|
| 2485 | {
|
---|
| 2486 | png_bytep sp = row + row_info->rowbytes;
|
---|
| 2487 | png_bytep dp = sp;
|
---|
| 2488 | png_byte save;
|
---|
| 2489 | png_uint_32 i;
|
---|
| 2490 |
|
---|
| 2491 | for (i = 0; i < row_width; i++)
|
---|
| 2492 | {
|
---|
| 2493 | save = *(--sp);
|
---|
| 2494 | *(--dp) = *(--sp);
|
---|
| 2495 | *(--dp) = *(--sp);
|
---|
| 2496 | *(--dp) = *(--sp);
|
---|
| 2497 | *(--dp) = save;
|
---|
| 2498 | }
|
---|
| 2499 | }
|
---|
| 2500 |
|
---|
| 2501 | #ifdef PNG_READ_16BIT_SUPPORTED
|
---|
| 2502 | /* This converts from RRGGBBAA to AARRGGBB */
|
---|
| 2503 | else
|
---|
| 2504 | {
|
---|
| 2505 | png_bytep sp = row + row_info->rowbytes;
|
---|
| 2506 | png_bytep dp = sp;
|
---|
| 2507 | png_byte save[2];
|
---|
| 2508 | png_uint_32 i;
|
---|
| 2509 |
|
---|
| 2510 | for (i = 0; i < row_width; i++)
|
---|
| 2511 | {
|
---|
| 2512 | save[0] = *(--sp);
|
---|
| 2513 | save[1] = *(--sp);
|
---|
| 2514 | *(--dp) = *(--sp);
|
---|
| 2515 | *(--dp) = *(--sp);
|
---|
| 2516 | *(--dp) = *(--sp);
|
---|
| 2517 | *(--dp) = *(--sp);
|
---|
| 2518 | *(--dp) = *(--sp);
|
---|
| 2519 | *(--dp) = *(--sp);
|
---|
| 2520 | *(--dp) = save[0];
|
---|
| 2521 | *(--dp) = save[1];
|
---|
| 2522 | }
|
---|
| 2523 | }
|
---|
| 2524 | #endif
|
---|
| 2525 | }
|
---|
| 2526 |
|
---|
| 2527 | else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
|
---|
| 2528 | {
|
---|
| 2529 | /* This converts from GA to AG */
|
---|
| 2530 | if (row_info->bit_depth == 8)
|
---|
| 2531 | {
|
---|
| 2532 | png_bytep sp = row + row_info->rowbytes;
|
---|
| 2533 | png_bytep dp = sp;
|
---|
| 2534 | png_byte save;
|
---|
| 2535 | png_uint_32 i;
|
---|
| 2536 |
|
---|
| 2537 | for (i = 0; i < row_width; i++)
|
---|
| 2538 | {
|
---|
| 2539 | save = *(--sp);
|
---|
| 2540 | *(--dp) = *(--sp);
|
---|
| 2541 | *(--dp) = save;
|
---|
| 2542 | }
|
---|
| 2543 | }
|
---|
| 2544 |
|
---|
| 2545 | #ifdef PNG_READ_16BIT_SUPPORTED
|
---|
| 2546 | /* This converts from GGAA to AAGG */
|
---|
| 2547 | else
|
---|
| 2548 | {
|
---|
| 2549 | png_bytep sp = row + row_info->rowbytes;
|
---|
| 2550 | png_bytep dp = sp;
|
---|
| 2551 | png_byte save[2];
|
---|
| 2552 | png_uint_32 i;
|
---|
| 2553 |
|
---|
| 2554 | for (i = 0; i < row_width; i++)
|
---|
| 2555 | {
|
---|
| 2556 | save[0] = *(--sp);
|
---|
| 2557 | save[1] = *(--sp);
|
---|
| 2558 | *(--dp) = *(--sp);
|
---|
| 2559 | *(--dp) = *(--sp);
|
---|
| 2560 | *(--dp) = save[0];
|
---|
| 2561 | *(--dp) = save[1];
|
---|
| 2562 | }
|
---|
| 2563 | }
|
---|
| 2564 | #endif
|
---|
| 2565 | }
|
---|
| 2566 | }
|
---|
| 2567 | #endif
|
---|
| 2568 |
|
---|
| 2569 | #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
|
---|
| 2570 | static void
|
---|
| 2571 | png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)
|
---|
| 2572 | {
|
---|
| 2573 | png_uint_32 row_width;
|
---|
| 2574 | png_debug(1, "in png_do_read_invert_alpha");
|
---|
| 2575 |
|
---|
| 2576 | row_width = row_info->width;
|
---|
| 2577 | if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
|
---|
| 2578 | {
|
---|
| 2579 | if (row_info->bit_depth == 8)
|
---|
| 2580 | {
|
---|
| 2581 | /* This inverts the alpha channel in RGBA */
|
---|
| 2582 | png_bytep sp = row + row_info->rowbytes;
|
---|
| 2583 | png_bytep dp = sp;
|
---|
| 2584 | png_uint_32 i;
|
---|
| 2585 |
|
---|
| 2586 | for (i = 0; i < row_width; i++)
|
---|
| 2587 | {
|
---|
| 2588 | *(--dp) = (png_byte)(255 - *(--sp));
|
---|
| 2589 |
|
---|
| 2590 | /* This does nothing:
|
---|
| 2591 | *(--dp) = *(--sp);
|
---|
| 2592 | *(--dp) = *(--sp);
|
---|
| 2593 | *(--dp) = *(--sp);
|
---|
| 2594 | We can replace it with:
|
---|
| 2595 | */
|
---|
| 2596 | sp-=3;
|
---|
| 2597 | dp=sp;
|
---|
| 2598 | }
|
---|
| 2599 | }
|
---|
| 2600 |
|
---|
| 2601 | #ifdef PNG_READ_16BIT_SUPPORTED
|
---|
| 2602 | /* This inverts the alpha channel in RRGGBBAA */
|
---|
| 2603 | else
|
---|
| 2604 | {
|
---|
| 2605 | png_bytep sp = row + row_info->rowbytes;
|
---|
| 2606 | png_bytep dp = sp;
|
---|
| 2607 | png_uint_32 i;
|
---|
| 2608 |
|
---|
| 2609 | for (i = 0; i < row_width; i++)
|
---|
| 2610 | {
|
---|
| 2611 | *(--dp) = (png_byte)(255 - *(--sp));
|
---|
| 2612 | *(--dp) = (png_byte)(255 - *(--sp));
|
---|
| 2613 |
|
---|
| 2614 | /* This does nothing:
|
---|
| 2615 | *(--dp) = *(--sp);
|
---|
| 2616 | *(--dp) = *(--sp);
|
---|
| 2617 | *(--dp) = *(--sp);
|
---|
| 2618 | *(--dp) = *(--sp);
|
---|
| 2619 | *(--dp) = *(--sp);
|
---|
| 2620 | *(--dp) = *(--sp);
|
---|
| 2621 | We can replace it with:
|
---|
| 2622 | */
|
---|
| 2623 | sp-=6;
|
---|
| 2624 | dp=sp;
|
---|
| 2625 | }
|
---|
| 2626 | }
|
---|
| 2627 | #endif
|
---|
| 2628 | }
|
---|
| 2629 | else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
|
---|
| 2630 | {
|
---|
| 2631 | if (row_info->bit_depth == 8)
|
---|
| 2632 | {
|
---|
| 2633 | /* This inverts the alpha channel in GA */
|
---|
| 2634 | png_bytep sp = row + row_info->rowbytes;
|
---|
| 2635 | png_bytep dp = sp;
|
---|
| 2636 | png_uint_32 i;
|
---|
| 2637 |
|
---|
| 2638 | for (i = 0; i < row_width; i++)
|
---|
| 2639 | {
|
---|
| 2640 | *(--dp) = (png_byte)(255 - *(--sp));
|
---|
| 2641 | *(--dp) = *(--sp);
|
---|
| 2642 | }
|
---|
| 2643 | }
|
---|
| 2644 |
|
---|
| 2645 | #ifdef PNG_READ_16BIT_SUPPORTED
|
---|
| 2646 | else
|
---|
| 2647 | {
|
---|
| 2648 | /* This inverts the alpha channel in GGAA */
|
---|
| 2649 | png_bytep sp = row + row_info->rowbytes;
|
---|
| 2650 | png_bytep dp = sp;
|
---|
| 2651 | png_uint_32 i;
|
---|
| 2652 |
|
---|
| 2653 | for (i = 0; i < row_width; i++)
|
---|
| 2654 | {
|
---|
| 2655 | *(--dp) = (png_byte)(255 - *(--sp));
|
---|
| 2656 | *(--dp) = (png_byte)(255 - *(--sp));
|
---|
| 2657 | /*
|
---|
| 2658 | *(--dp) = *(--sp);
|
---|
| 2659 | *(--dp) = *(--sp);
|
---|
| 2660 | */
|
---|
| 2661 | sp-=2;
|
---|
| 2662 | dp=sp;
|
---|
| 2663 | }
|
---|
| 2664 | }
|
---|
| 2665 | #endif
|
---|
| 2666 | }
|
---|
| 2667 | }
|
---|
| 2668 | #endif
|
---|
| 2669 |
|
---|
| 2670 | #ifdef PNG_READ_FILLER_SUPPORTED
|
---|
| 2671 | /* Add filler channel if we have RGB color */
|
---|
| 2672 | static void
|
---|
| 2673 | png_do_read_filler(png_row_infop row_info, png_bytep row,
|
---|
| 2674 | png_uint_32 filler, png_uint_32 flags)
|
---|
| 2675 | {
|
---|
| 2676 | png_uint_32 i;
|
---|
| 2677 | png_uint_32 row_width = row_info->width;
|
---|
| 2678 |
|
---|
| 2679 | #ifdef PNG_READ_16BIT_SUPPORTED
|
---|
| 2680 | png_byte hi_filler = (png_byte)(filler>>8);
|
---|
| 2681 | #endif
|
---|
| 2682 | png_byte lo_filler = (png_byte)filler;
|
---|
| 2683 |
|
---|
| 2684 | png_debug(1, "in png_do_read_filler");
|
---|
| 2685 |
|
---|
| 2686 | if (
|
---|
| 2687 | row_info->color_type == PNG_COLOR_TYPE_GRAY)
|
---|
| 2688 | {
|
---|
| 2689 | if (row_info->bit_depth == 8)
|
---|
| 2690 | {
|
---|
| 2691 | if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
|
---|
| 2692 | {
|
---|
| 2693 | /* This changes the data from G to GX */
|
---|
| 2694 | png_bytep sp = row + (size_t)row_width;
|
---|
| 2695 | png_bytep dp = sp + (size_t)row_width;
|
---|
| 2696 | for (i = 1; i < row_width; i++)
|
---|
| 2697 | {
|
---|
| 2698 | *(--dp) = lo_filler;
|
---|
| 2699 | *(--dp) = *(--sp);
|
---|
| 2700 | }
|
---|
| 2701 | *(--dp) = lo_filler;
|
---|
| 2702 | row_info->channels = 2;
|
---|
| 2703 | row_info->pixel_depth = 16;
|
---|
| 2704 | row_info->rowbytes = row_width * 2;
|
---|
| 2705 | }
|
---|
| 2706 |
|
---|
| 2707 | else
|
---|
| 2708 | {
|
---|
| 2709 | /* This changes the data from G to XG */
|
---|
| 2710 | png_bytep sp = row + (size_t)row_width;
|
---|
| 2711 | png_bytep dp = sp + (size_t)row_width;
|
---|
| 2712 | for (i = 0; i < row_width; i++)
|
---|
| 2713 | {
|
---|
| 2714 | *(--dp) = *(--sp);
|
---|
| 2715 | *(--dp) = lo_filler;
|
---|
| 2716 | }
|
---|
| 2717 | row_info->channels = 2;
|
---|
| 2718 | row_info->pixel_depth = 16;
|
---|
| 2719 | row_info->rowbytes = row_width * 2;
|
---|
| 2720 | }
|
---|
| 2721 | }
|
---|
| 2722 |
|
---|
| 2723 | #ifdef PNG_READ_16BIT_SUPPORTED
|
---|
| 2724 | else if (row_info->bit_depth == 16)
|
---|
| 2725 | {
|
---|
| 2726 | if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
|
---|
| 2727 | {
|
---|
| 2728 | /* This changes the data from GG to GGXX */
|
---|
| 2729 | png_bytep sp = row + (size_t)row_width * 2;
|
---|
| 2730 | png_bytep dp = sp + (size_t)row_width * 2;
|
---|
| 2731 | for (i = 1; i < row_width; i++)
|
---|
| 2732 | {
|
---|
| 2733 | *(--dp) = lo_filler;
|
---|
| 2734 | *(--dp) = hi_filler;
|
---|
| 2735 | *(--dp) = *(--sp);
|
---|
| 2736 | *(--dp) = *(--sp);
|
---|
| 2737 | }
|
---|
| 2738 | *(--dp) = lo_filler;
|
---|
| 2739 | *(--dp) = hi_filler;
|
---|
| 2740 | row_info->channels = 2;
|
---|
| 2741 | row_info->pixel_depth = 32;
|
---|
| 2742 | row_info->rowbytes = row_width * 4;
|
---|
| 2743 | }
|
---|
| 2744 |
|
---|
| 2745 | else
|
---|
| 2746 | {
|
---|
| 2747 | /* This changes the data from GG to XXGG */
|
---|
| 2748 | png_bytep sp = row + (size_t)row_width * 2;
|
---|
| 2749 | png_bytep dp = sp + (size_t)row_width * 2;
|
---|
| 2750 | for (i = 0; i < row_width; i++)
|
---|
| 2751 | {
|
---|
| 2752 | *(--dp) = *(--sp);
|
---|
| 2753 | *(--dp) = *(--sp);
|
---|
| 2754 | *(--dp) = lo_filler;
|
---|
| 2755 | *(--dp) = hi_filler;
|
---|
| 2756 | }
|
---|
| 2757 | row_info->channels = 2;
|
---|
| 2758 | row_info->pixel_depth = 32;
|
---|
| 2759 | row_info->rowbytes = row_width * 4;
|
---|
| 2760 | }
|
---|
| 2761 | }
|
---|
| 2762 | #endif
|
---|
| 2763 | } /* COLOR_TYPE == GRAY */
|
---|
| 2764 | else if (row_info->color_type == PNG_COLOR_TYPE_RGB)
|
---|
| 2765 | {
|
---|
| 2766 | if (row_info->bit_depth == 8)
|
---|
| 2767 | {
|
---|
| 2768 | if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
|
---|
| 2769 | {
|
---|
| 2770 | /* This changes the data from RGB to RGBX */
|
---|
| 2771 | png_bytep sp = row + (size_t)row_width * 3;
|
---|
| 2772 | png_bytep dp = sp + (size_t)row_width;
|
---|
| 2773 | for (i = 1; i < row_width; i++)
|
---|
| 2774 | {
|
---|
| 2775 | *(--dp) = lo_filler;
|
---|
| 2776 | *(--dp) = *(--sp);
|
---|
| 2777 | *(--dp) = *(--sp);
|
---|
| 2778 | *(--dp) = *(--sp);
|
---|
| 2779 | }
|
---|
| 2780 | *(--dp) = lo_filler;
|
---|
| 2781 | row_info->channels = 4;
|
---|
| 2782 | row_info->pixel_depth = 32;
|
---|
| 2783 | row_info->rowbytes = row_width * 4;
|
---|
| 2784 | }
|
---|
| 2785 |
|
---|
| 2786 | else
|
---|
| 2787 | {
|
---|
| 2788 | /* This changes the data from RGB to XRGB */
|
---|
| 2789 | png_bytep sp = row + (size_t)row_width * 3;
|
---|
| 2790 | png_bytep dp = sp + (size_t)row_width;
|
---|
| 2791 | for (i = 0; i < row_width; i++)
|
---|
| 2792 | {
|
---|
| 2793 | *(--dp) = *(--sp);
|
---|
| 2794 | *(--dp) = *(--sp);
|
---|
| 2795 | *(--dp) = *(--sp);
|
---|
| 2796 | *(--dp) = lo_filler;
|
---|
| 2797 | }
|
---|
| 2798 | row_info->channels = 4;
|
---|
| 2799 | row_info->pixel_depth = 32;
|
---|
| 2800 | row_info->rowbytes = row_width * 4;
|
---|
| 2801 | }
|
---|
| 2802 | }
|
---|
| 2803 |
|
---|
| 2804 | #ifdef PNG_READ_16BIT_SUPPORTED
|
---|
| 2805 | else if (row_info->bit_depth == 16)
|
---|
| 2806 | {
|
---|
| 2807 | if ((flags & PNG_FLAG_FILLER_AFTER) != 0)
|
---|
| 2808 | {
|
---|
| 2809 | /* This changes the data from RRGGBB to RRGGBBXX */
|
---|
| 2810 | png_bytep sp = row + (size_t)row_width * 6;
|
---|
| 2811 | png_bytep dp = sp + (size_t)row_width * 2;
|
---|
| 2812 | for (i = 1; i < row_width; i++)
|
---|
| 2813 | {
|
---|
| 2814 | *(--dp) = lo_filler;
|
---|
| 2815 | *(--dp) = hi_filler;
|
---|
| 2816 | *(--dp) = *(--sp);
|
---|
| 2817 | *(--dp) = *(--sp);
|
---|
| 2818 | *(--dp) = *(--sp);
|
---|
| 2819 | *(--dp) = *(--sp);
|
---|
| 2820 | *(--dp) = *(--sp);
|
---|
| 2821 | *(--dp) = *(--sp);
|
---|
| 2822 | }
|
---|
| 2823 | *(--dp) = lo_filler;
|
---|
| 2824 | *(--dp) = hi_filler;
|
---|
| 2825 | row_info->channels = 4;
|
---|
| 2826 | row_info->pixel_depth = 64;
|
---|
| 2827 | row_info->rowbytes = row_width * 8;
|
---|
| 2828 | }
|
---|
| 2829 |
|
---|
| 2830 | else
|
---|
| 2831 | {
|
---|
| 2832 | /* This changes the data from RRGGBB to XXRRGGBB */
|
---|
| 2833 | png_bytep sp = row + (size_t)row_width * 6;
|
---|
| 2834 | png_bytep dp = sp + (size_t)row_width * 2;
|
---|
| 2835 | for (i = 0; i < row_width; i++)
|
---|
| 2836 | {
|
---|
| 2837 | *(--dp) = *(--sp);
|
---|
| 2838 | *(--dp) = *(--sp);
|
---|
| 2839 | *(--dp) = *(--sp);
|
---|
| 2840 | *(--dp) = *(--sp);
|
---|
| 2841 | *(--dp) = *(--sp);
|
---|
| 2842 | *(--dp) = *(--sp);
|
---|
| 2843 | *(--dp) = lo_filler;
|
---|
| 2844 | *(--dp) = hi_filler;
|
---|
| 2845 | }
|
---|
| 2846 |
|
---|
| 2847 | row_info->channels = 4;
|
---|
| 2848 | row_info->pixel_depth = 64;
|
---|
| 2849 | row_info->rowbytes = row_width * 8;
|
---|
| 2850 | }
|
---|
| 2851 | }
|
---|
| 2852 | #endif
|
---|
| 2853 | } /* COLOR_TYPE == RGB */
|
---|
| 2854 | }
|
---|
| 2855 | #endif
|
---|
| 2856 |
|
---|
| 2857 | #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
|
---|
| 2858 | /* Expand grayscale files to RGB, with or without alpha */
|
---|
| 2859 | static void
|
---|
| 2860 | png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
|
---|
| 2861 | {
|
---|
| 2862 | png_uint_32 i;
|
---|
| 2863 | png_uint_32 row_width = row_info->width;
|
---|
| 2864 |
|
---|
| 2865 | png_debug(1, "in png_do_gray_to_rgb");
|
---|
| 2866 |
|
---|
| 2867 | if (row_info->bit_depth >= 8 &&
|
---|
| 2868 | (row_info->color_type & PNG_COLOR_MASK_COLOR) == 0)
|
---|
| 2869 | {
|
---|
| 2870 | if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
|
---|
| 2871 | {
|
---|
| 2872 | if (row_info->bit_depth == 8)
|
---|
| 2873 | {
|
---|
| 2874 | /* This changes G to RGB */
|
---|
| 2875 | png_bytep sp = row + (size_t)row_width - 1;
|
---|
| 2876 | png_bytep dp = sp + (size_t)row_width * 2;
|
---|
| 2877 | for (i = 0; i < row_width; i++)
|
---|
| 2878 | {
|
---|
| 2879 | *(dp--) = *sp;
|
---|
| 2880 | *(dp--) = *sp;
|
---|
| 2881 | *(dp--) = *(sp--);
|
---|
| 2882 | }
|
---|
| 2883 | }
|
---|
| 2884 |
|
---|
| 2885 | else
|
---|
| 2886 | {
|
---|
| 2887 | /* This changes GG to RRGGBB */
|
---|
| 2888 | png_bytep sp = row + (size_t)row_width * 2 - 1;
|
---|
| 2889 | png_bytep dp = sp + (size_t)row_width * 4;
|
---|
| 2890 | for (i = 0; i < row_width; i++)
|
---|
| 2891 | {
|
---|
| 2892 | *(dp--) = *sp;
|
---|
| 2893 | *(dp--) = *(sp - 1);
|
---|
| 2894 | *(dp--) = *sp;
|
---|
| 2895 | *(dp--) = *(sp - 1);
|
---|
| 2896 | *(dp--) = *(sp--);
|
---|
| 2897 | *(dp--) = *(sp--);
|
---|
| 2898 | }
|
---|
| 2899 | }
|
---|
| 2900 | }
|
---|
| 2901 |
|
---|
| 2902 | else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
|
---|
| 2903 | {
|
---|
| 2904 | if (row_info->bit_depth == 8)
|
---|
| 2905 | {
|
---|
| 2906 | /* This changes GA to RGBA */
|
---|
| 2907 | png_bytep sp = row + (size_t)row_width * 2 - 1;
|
---|
| 2908 | png_bytep dp = sp + (size_t)row_width * 2;
|
---|
| 2909 | for (i = 0; i < row_width; i++)
|
---|
| 2910 | {
|
---|
| 2911 | *(dp--) = *(sp--);
|
---|
| 2912 | *(dp--) = *sp;
|
---|
| 2913 | *(dp--) = *sp;
|
---|
| 2914 | *(dp--) = *(sp--);
|
---|
| 2915 | }
|
---|
| 2916 | }
|
---|
| 2917 |
|
---|
| 2918 | else
|
---|
| 2919 | {
|
---|
| 2920 | /* This changes GGAA to RRGGBBAA */
|
---|
| 2921 | png_bytep sp = row + (size_t)row_width * 4 - 1;
|
---|
| 2922 | png_bytep dp = sp + (size_t)row_width * 4;
|
---|
| 2923 | for (i = 0; i < row_width; i++)
|
---|
| 2924 | {
|
---|
| 2925 | *(dp--) = *(sp--);
|
---|
| 2926 | *(dp--) = *(sp--);
|
---|
| 2927 | *(dp--) = *sp;
|
---|
| 2928 | *(dp--) = *(sp - 1);
|
---|
| 2929 | *(dp--) = *sp;
|
---|
| 2930 | *(dp--) = *(sp - 1);
|
---|
| 2931 | *(dp--) = *(sp--);
|
---|
| 2932 | *(dp--) = *(sp--);
|
---|
| 2933 | }
|
---|
| 2934 | }
|
---|
| 2935 | }
|
---|
| 2936 | row_info->channels = (png_byte)(row_info->channels + 2);
|
---|
| 2937 | row_info->color_type |= PNG_COLOR_MASK_COLOR;
|
---|
| 2938 | row_info->pixel_depth = (png_byte)(row_info->channels *
|
---|
| 2939 | row_info->bit_depth);
|
---|
| 2940 | row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
|
---|
| 2941 | }
|
---|
| 2942 | }
|
---|
| 2943 | #endif
|
---|
| 2944 |
|
---|
| 2945 | #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
|
---|
| 2946 | /* Reduce RGB files to grayscale, with or without alpha
|
---|
| 2947 | * using the equation given in Poynton's ColorFAQ of 1998-01-04 at
|
---|
| 2948 | * <http://www.inforamp.net/~poynton/> (THIS LINK IS DEAD June 2008 but
|
---|
| 2949 | * versions dated 1998 through November 2002 have been archived at
|
---|
| 2950 | * https://web.archive.org/web/20000816232553/www.inforamp.net/
|
---|
| 2951 | * ~poynton/notes/colour_and_gamma/ColorFAQ.txt )
|
---|
| 2952 | * Charles Poynton poynton at poynton.com
|
---|
| 2953 | *
|
---|
| 2954 | * Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
|
---|
| 2955 | *
|
---|
| 2956 | * which can be expressed with integers as
|
---|
| 2957 | *
|
---|
| 2958 | * Y = (6969 * R + 23434 * G + 2365 * B)/32768
|
---|
| 2959 | *
|
---|
| 2960 | * Poynton's current link (as of January 2003 through July 2011):
|
---|
| 2961 | * <http://www.poynton.com/notes/colour_and_gamma/>
|
---|
| 2962 | * has changed the numbers slightly:
|
---|
| 2963 | *
|
---|
| 2964 | * Y = 0.2126*R + 0.7152*G + 0.0722*B
|
---|
| 2965 | *
|
---|
| 2966 | * which can be expressed with integers as
|
---|
| 2967 | *
|
---|
| 2968 | * Y = (6966 * R + 23436 * G + 2366 * B)/32768
|
---|
| 2969 | *
|
---|
| 2970 | * Historically, however, libpng uses numbers derived from the ITU-R Rec 709
|
---|
| 2971 | * end point chromaticities and the D65 white point. Depending on the
|
---|
| 2972 | * precision used for the D65 white point this produces a variety of different
|
---|
| 2973 | * numbers, however if the four decimal place value used in ITU-R Rec 709 is
|
---|
| 2974 | * used (0.3127,0.3290) the Y calculation would be:
|
---|
| 2975 | *
|
---|
| 2976 | * Y = (6968 * R + 23435 * G + 2366 * B)/32768
|
---|
| 2977 | *
|
---|
| 2978 | * While this is correct the rounding results in an overflow for white, because
|
---|
| 2979 | * the sum of the rounded coefficients is 32769, not 32768. Consequently
|
---|
| 2980 | * libpng uses, instead, the closest non-overflowing approximation:
|
---|
| 2981 | *
|
---|
| 2982 | * Y = (6968 * R + 23434 * G + 2366 * B)/32768
|
---|
| 2983 | *
|
---|
| 2984 | * Starting with libpng-1.5.5, if the image being converted has a cHRM chunk
|
---|
| 2985 | * (including an sRGB chunk) then the chromaticities are used to calculate the
|
---|
| 2986 | * coefficients. See the chunk handling in pngrutil.c for more information.
|
---|
| 2987 | *
|
---|
| 2988 | * In all cases the calculation is to be done in a linear colorspace. If no
|
---|
| 2989 | * gamma information is available to correct the encoding of the original RGB
|
---|
| 2990 | * values this results in an implicit assumption that the original PNG RGB
|
---|
| 2991 | * values were linear.
|
---|
| 2992 | *
|
---|
| 2993 | * Other integer coefficients can be used via png_set_rgb_to_gray(). Because
|
---|
| 2994 | * the API takes just red and green coefficients the blue coefficient is
|
---|
| 2995 | * calculated to make the sum 32768. This will result in different rounding
|
---|
| 2996 | * to that used above.
|
---|
| 2997 | */
|
---|
| 2998 | static int
|
---|
| 2999 | png_do_rgb_to_gray(png_structrp png_ptr, png_row_infop row_info, png_bytep row)
|
---|
| 3000 | {
|
---|
| 3001 | int rgb_error = 0;
|
---|
| 3002 |
|
---|
| 3003 | png_debug(1, "in png_do_rgb_to_gray");
|
---|
| 3004 |
|
---|
| 3005 | if ((row_info->color_type & PNG_COLOR_MASK_PALETTE) == 0 &&
|
---|
| 3006 | (row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
|
---|
| 3007 | {
|
---|
| 3008 | png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff;
|
---|
| 3009 | png_uint_32 gc = png_ptr->rgb_to_gray_green_coeff;
|
---|
| 3010 | png_uint_32 bc = 32768 - rc - gc;
|
---|
| 3011 | png_uint_32 row_width = row_info->width;
|
---|
| 3012 | int have_alpha = (row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0;
|
---|
| 3013 |
|
---|
| 3014 | if (row_info->bit_depth == 8)
|
---|
| 3015 | {
|
---|
| 3016 | #ifdef PNG_READ_GAMMA_SUPPORTED
|
---|
| 3017 | /* Notice that gamma to/from 1 are not necessarily inverses (if
|
---|
| 3018 | * there is an overall gamma correction). Prior to 1.5.5 this code
|
---|
| 3019 | * checked the linearized values for equality; this doesn't match
|
---|
| 3020 | * the documentation, the original values must be checked.
|
---|
| 3021 | */
|
---|
| 3022 | if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL)
|
---|
| 3023 | {
|
---|
| 3024 | png_bytep sp = row;
|
---|
| 3025 | png_bytep dp = row;
|
---|
| 3026 | png_uint_32 i;
|
---|
| 3027 |
|
---|
| 3028 | for (i = 0; i < row_width; i++)
|
---|
| 3029 | {
|
---|
| 3030 | png_byte red = *(sp++);
|
---|
| 3031 | png_byte green = *(sp++);
|
---|
| 3032 | png_byte blue = *(sp++);
|
---|
| 3033 |
|
---|
| 3034 | if (red != green || red != blue)
|
---|
| 3035 | {
|
---|
| 3036 | red = png_ptr->gamma_to_1[red];
|
---|
| 3037 | green = png_ptr->gamma_to_1[green];
|
---|
| 3038 | blue = png_ptr->gamma_to_1[blue];
|
---|
| 3039 |
|
---|
| 3040 | rgb_error |= 1;
|
---|
| 3041 | *(dp++) = png_ptr->gamma_from_1[
|
---|
| 3042 | (rc*red + gc*green + bc*blue + 16384)>>15];
|
---|
| 3043 | }
|
---|
| 3044 |
|
---|
| 3045 | else
|
---|
| 3046 | {
|
---|
| 3047 | /* If there is no overall correction the table will not be
|
---|
| 3048 | * set.
|
---|
| 3049 | */
|
---|
| 3050 | if (png_ptr->gamma_table != NULL)
|
---|
| 3051 | red = png_ptr->gamma_table[red];
|
---|
| 3052 |
|
---|
| 3053 | *(dp++) = red;
|
---|
| 3054 | }
|
---|
| 3055 |
|
---|
| 3056 | if (have_alpha != 0)
|
---|
| 3057 | *(dp++) = *(sp++);
|
---|
| 3058 | }
|
---|
| 3059 | }
|
---|
| 3060 | else
|
---|
| 3061 | #endif
|
---|
| 3062 | {
|
---|
| 3063 | png_bytep sp = row;
|
---|
| 3064 | png_bytep dp = row;
|
---|
| 3065 | png_uint_32 i;
|
---|
| 3066 |
|
---|
| 3067 | for (i = 0; i < row_width; i++)
|
---|
| 3068 | {
|
---|
| 3069 | png_byte red = *(sp++);
|
---|
| 3070 | png_byte green = *(sp++);
|
---|
| 3071 | png_byte blue = *(sp++);
|
---|
| 3072 |
|
---|
| 3073 | if (red != green || red != blue)
|
---|
| 3074 | {
|
---|
| 3075 | rgb_error |= 1;
|
---|
| 3076 | /* NOTE: this is the historical approach which simply
|
---|
| 3077 | * truncates the results.
|
---|
| 3078 | */
|
---|
| 3079 | *(dp++) = (png_byte)((rc*red + gc*green + bc*blue)>>15);
|
---|
| 3080 | }
|
---|
| 3081 |
|
---|
| 3082 | else
|
---|
| 3083 | *(dp++) = red;
|
---|
| 3084 |
|
---|
| 3085 | if (have_alpha != 0)
|
---|
| 3086 | *(dp++) = *(sp++);
|
---|
| 3087 | }
|
---|
| 3088 | }
|
---|
| 3089 | }
|
---|
| 3090 |
|
---|
| 3091 | else /* RGB bit_depth == 16 */
|
---|
| 3092 | {
|
---|
| 3093 | #ifdef PNG_READ_GAMMA_SUPPORTED
|
---|
| 3094 | if (png_ptr->gamma_16_to_1 != NULL && png_ptr->gamma_16_from_1 != NULL)
|
---|
| 3095 | {
|
---|
| 3096 | png_bytep sp = row;
|
---|
| 3097 | png_bytep dp = row;
|
---|
| 3098 | png_uint_32 i;
|
---|
| 3099 |
|
---|
| 3100 | for (i = 0; i < row_width; i++)
|
---|
| 3101 | {
|
---|
| 3102 | png_uint_16 red, green, blue, w;
|
---|
| 3103 | png_byte hi,lo;
|
---|
| 3104 |
|
---|
| 3105 | hi=*(sp)++; lo=*(sp)++; red = (png_uint_16)((hi << 8) | (lo));
|
---|
| 3106 | hi=*(sp)++; lo=*(sp)++; green = (png_uint_16)((hi << 8) | (lo));
|
---|
| 3107 | hi=*(sp)++; lo=*(sp)++; blue = (png_uint_16)((hi << 8) | (lo));
|
---|
| 3108 |
|
---|
| 3109 | if (red == green && red == blue)
|
---|
| 3110 | {
|
---|
| 3111 | if (png_ptr->gamma_16_table != NULL)
|
---|
| 3112 | w = png_ptr->gamma_16_table[(red & 0xff)
|
---|
| 3113 | >> png_ptr->gamma_shift][red >> 8];
|
---|
| 3114 |
|
---|
| 3115 | else
|
---|
| 3116 | w = red;
|
---|
| 3117 | }
|
---|
| 3118 |
|
---|
| 3119 | else
|
---|
| 3120 | {
|
---|
| 3121 | png_uint_16 red_1 = png_ptr->gamma_16_to_1[(red & 0xff)
|
---|
| 3122 | >> png_ptr->gamma_shift][red>>8];
|
---|
| 3123 | png_uint_16 green_1 =
|
---|
| 3124 | png_ptr->gamma_16_to_1[(green & 0xff) >>
|
---|
| 3125 | png_ptr->gamma_shift][green>>8];
|
---|
| 3126 | png_uint_16 blue_1 = png_ptr->gamma_16_to_1[(blue & 0xff)
|
---|
| 3127 | >> png_ptr->gamma_shift][blue>>8];
|
---|
| 3128 | png_uint_16 gray16 = (png_uint_16)((rc*red_1 + gc*green_1
|
---|
| 3129 | + bc*blue_1 + 16384)>>15);
|
---|
| 3130 | w = png_ptr->gamma_16_from_1[(gray16 & 0xff) >>
|
---|
| 3131 | png_ptr->gamma_shift][gray16 >> 8];
|
---|
| 3132 | rgb_error |= 1;
|
---|
| 3133 | }
|
---|
| 3134 |
|
---|
| 3135 | *(dp++) = (png_byte)((w>>8) & 0xff);
|
---|
| 3136 | *(dp++) = (png_byte)(w & 0xff);
|
---|
| 3137 |
|
---|
| 3138 | if (have_alpha != 0)
|
---|
| 3139 | {
|
---|
| 3140 | *(dp++) = *(sp++);
|
---|
| 3141 | *(dp++) = *(sp++);
|
---|
| 3142 | }
|
---|
| 3143 | }
|
---|
| 3144 | }
|
---|
| 3145 | else
|
---|
| 3146 | #endif
|
---|
| 3147 | {
|
---|
| 3148 | png_bytep sp = row;
|
---|
| 3149 | png_bytep dp = row;
|
---|
| 3150 | png_uint_32 i;
|
---|
| 3151 |
|
---|
| 3152 | for (i = 0; i < row_width; i++)
|
---|
| 3153 | {
|
---|
| 3154 | png_uint_16 red, green, blue, gray16;
|
---|
| 3155 | png_byte hi,lo;
|
---|
| 3156 |
|
---|
| 3157 | hi=*(sp)++; lo=*(sp)++; red = (png_uint_16)((hi << 8) | (lo));
|
---|
| 3158 | hi=*(sp)++; lo=*(sp)++; green = (png_uint_16)((hi << 8) | (lo));
|
---|
| 3159 | hi=*(sp)++; lo=*(sp)++; blue = (png_uint_16)((hi << 8) | (lo));
|
---|
| 3160 |
|
---|
| 3161 | if (red != green || red != blue)
|
---|
| 3162 | rgb_error |= 1;
|
---|
| 3163 |
|
---|
| 3164 | /* From 1.5.5 in the 16-bit case do the accurate conversion even
|
---|
| 3165 | * in the 'fast' case - this is because this is where the code
|
---|
| 3166 | * ends up when handling linear 16-bit data.
|
---|
| 3167 | */
|
---|
| 3168 | gray16 = (png_uint_16)((rc*red + gc*green + bc*blue + 16384) >>
|
---|
| 3169 | 15);
|
---|
| 3170 | *(dp++) = (png_byte)((gray16 >> 8) & 0xff);
|
---|
| 3171 | *(dp++) = (png_byte)(gray16 & 0xff);
|
---|
| 3172 |
|
---|
| 3173 | if (have_alpha != 0)
|
---|
| 3174 | {
|
---|
| 3175 | *(dp++) = *(sp++);
|
---|
| 3176 | *(dp++) = *(sp++);
|
---|
| 3177 | }
|
---|
| 3178 | }
|
---|
| 3179 | }
|
---|
| 3180 | }
|
---|
| 3181 |
|
---|
| 3182 | row_info->channels = (png_byte)(row_info->channels - 2);
|
---|
| 3183 | row_info->color_type = (png_byte)(row_info->color_type &
|
---|
| 3184 | ~PNG_COLOR_MASK_COLOR);
|
---|
| 3185 | row_info->pixel_depth = (png_byte)(row_info->channels *
|
---|
| 3186 | row_info->bit_depth);
|
---|
| 3187 | row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
|
---|
| 3188 | }
|
---|
| 3189 | return rgb_error;
|
---|
| 3190 | }
|
---|
| 3191 | #endif
|
---|
| 3192 |
|
---|
| 3193 | #if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
|
---|
| 3194 | defined(PNG_READ_ALPHA_MODE_SUPPORTED)
|
---|
| 3195 | /* Replace any alpha or transparency with the supplied background color.
|
---|
| 3196 | * "background" is already in the screen gamma, while "background_1" is
|
---|
| 3197 | * at a gamma of 1.0. Paletted files have already been taken care of.
|
---|
| 3198 | */
|
---|
| 3199 | static void
|
---|
| 3200 | png_do_compose(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
|
---|
| 3201 | {
|
---|
| 3202 | #ifdef PNG_READ_GAMMA_SUPPORTED
|
---|
| 3203 | png_const_bytep gamma_table = png_ptr->gamma_table;
|
---|
| 3204 | png_const_bytep gamma_from_1 = png_ptr->gamma_from_1;
|
---|
| 3205 | png_const_bytep gamma_to_1 = png_ptr->gamma_to_1;
|
---|
| 3206 | png_const_uint_16pp gamma_16 = png_ptr->gamma_16_table;
|
---|
| 3207 | png_const_uint_16pp gamma_16_from_1 = png_ptr->gamma_16_from_1;
|
---|
| 3208 | png_const_uint_16pp gamma_16_to_1 = png_ptr->gamma_16_to_1;
|
---|
| 3209 | int gamma_shift = png_ptr->gamma_shift;
|
---|
| 3210 | int optimize = (png_ptr->flags & PNG_FLAG_OPTIMIZE_ALPHA) != 0;
|
---|
| 3211 | #endif
|
---|
| 3212 |
|
---|
| 3213 | png_bytep sp;
|
---|
| 3214 | png_uint_32 i;
|
---|
| 3215 | png_uint_32 row_width = row_info->width;
|
---|
| 3216 | int shift;
|
---|
| 3217 |
|
---|
| 3218 | png_debug(1, "in png_do_compose");
|
---|
| 3219 |
|
---|
| 3220 | switch (row_info->color_type)
|
---|
| 3221 | {
|
---|
| 3222 | case PNG_COLOR_TYPE_GRAY:
|
---|
| 3223 | {
|
---|
| 3224 | switch (row_info->bit_depth)
|
---|
| 3225 | {
|
---|
| 3226 | case 1:
|
---|
| 3227 | {
|
---|
| 3228 | sp = row;
|
---|
| 3229 | shift = 7;
|
---|
| 3230 | for (i = 0; i < row_width; i++)
|
---|
| 3231 | {
|
---|
| 3232 | if ((png_uint_16)((*sp >> shift) & 0x01)
|
---|
| 3233 | == png_ptr->trans_color.gray)
|
---|
| 3234 | {
|
---|
| 3235 | unsigned int tmp = *sp & (0x7f7f >> (7 - shift));
|
---|
| 3236 | tmp |=
|
---|
| 3237 | (unsigned int)(png_ptr->background.gray << shift);
|
---|
| 3238 | *sp = (png_byte)(tmp & 0xff);
|
---|
| 3239 | }
|
---|
| 3240 |
|
---|
| 3241 | if (shift == 0)
|
---|
| 3242 | {
|
---|
| 3243 | shift = 7;
|
---|
| 3244 | sp++;
|
---|
| 3245 | }
|
---|
| 3246 |
|
---|
| 3247 | else
|
---|
| 3248 | shift--;
|
---|
| 3249 | }
|
---|
| 3250 | break;
|
---|
| 3251 | }
|
---|
| 3252 |
|
---|
| 3253 | case 2:
|
---|
| 3254 | {
|
---|
| 3255 | #ifdef PNG_READ_GAMMA_SUPPORTED
|
---|
| 3256 | if (gamma_table != NULL)
|
---|
| 3257 | {
|
---|
| 3258 | sp = row;
|
---|
| 3259 | shift = 6;
|
---|
| 3260 | for (i = 0; i < row_width; i++)
|
---|
| 3261 | {
|
---|
| 3262 | if ((png_uint_16)((*sp >> shift) & 0x03)
|
---|
| 3263 | == png_ptr->trans_color.gray)
|
---|
| 3264 | {
|
---|
| 3265 | unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
|
---|
| 3266 | tmp |=
|
---|
| 3267 | (unsigned int)png_ptr->background.gray << shift;
|
---|
| 3268 | *sp = (png_byte)(tmp & 0xff);
|
---|
| 3269 | }
|
---|
| 3270 |
|
---|
| 3271 | else
|
---|
| 3272 | {
|
---|
| 3273 | unsigned int p = (*sp >> shift) & 0x03;
|
---|
| 3274 | unsigned int g = (gamma_table [p | (p << 2) |
|
---|
| 3275 | (p << 4) | (p << 6)] >> 6) & 0x03;
|
---|
| 3276 | unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
|
---|
| 3277 | tmp |= (unsigned int)(g << shift);
|
---|
| 3278 | *sp = (png_byte)(tmp & 0xff);
|
---|
| 3279 | }
|
---|
| 3280 |
|
---|
| 3281 | if (shift == 0)
|
---|
| 3282 | {
|
---|
| 3283 | shift = 6;
|
---|
| 3284 | sp++;
|
---|
| 3285 | }
|
---|
| 3286 |
|
---|
| 3287 | else
|
---|
| 3288 | shift -= 2;
|
---|
| 3289 | }
|
---|
| 3290 | }
|
---|
| 3291 |
|
---|
| 3292 | else
|
---|
| 3293 | #endif
|
---|
| 3294 | {
|
---|
| 3295 | sp = row;
|
---|
| 3296 | shift = 6;
|
---|
| 3297 | for (i = 0; i < row_width; i++)
|
---|
| 3298 | {
|
---|
| 3299 | if ((png_uint_16)((*sp >> shift) & 0x03)
|
---|
| 3300 | == png_ptr->trans_color.gray)
|
---|
| 3301 | {
|
---|
| 3302 | unsigned int tmp = *sp & (0x3f3f >> (6 - shift));
|
---|
| 3303 | tmp |=
|
---|
| 3304 | (unsigned int)png_ptr->background.gray << shift;
|
---|
| 3305 | *sp = (png_byte)(tmp & 0xff);
|
---|
| 3306 | }
|
---|
| 3307 |
|
---|
| 3308 | if (shift == 0)
|
---|
| 3309 | {
|
---|
| 3310 | shift = 6;
|
---|
| 3311 | sp++;
|
---|
| 3312 | }
|
---|
| 3313 |
|
---|
| 3314 | else
|
---|
| 3315 | shift -= 2;
|
---|
| 3316 | }
|
---|
| 3317 | }
|
---|
| 3318 | break;
|
---|
| 3319 | }
|
---|
| 3320 |
|
---|
| 3321 | case 4:
|
---|
| 3322 | {
|
---|
| 3323 | #ifdef PNG_READ_GAMMA_SUPPORTED
|
---|
| 3324 | if (gamma_table != NULL)
|
---|
| 3325 | {
|
---|
| 3326 | sp = row;
|
---|
| 3327 | shift = 4;
|
---|
| 3328 | for (i = 0; i < row_width; i++)
|
---|
| 3329 | {
|
---|
| 3330 | if ((png_uint_16)((*sp >> shift) & 0x0f)
|
---|
| 3331 | == png_ptr->trans_color.gray)
|
---|
| 3332 | {
|
---|
| 3333 | unsigned int tmp = *sp & (0x0f0f >> (4 - shift));
|
---|
| 3334 | tmp |=
|
---|
| 3335 | (unsigned int)(png_ptr->background.gray << shift);
|
---|
| 3336 | *sp = (png_byte)(tmp & 0xff);
|
---|
| 3337 | }
|
---|
| 3338 |
|
---|
| 3339 | else
|
---|
| 3340 | {
|
---|
| 3341 | unsigned int p = (*sp >> shift) & 0x0f;
|
---|
| 3342 | unsigned int g = (gamma_table[p | (p << 4)] >> 4) &
|
---|
| 3343 | 0x0f;
|
---|
| 3344 | unsigned int tmp = *sp & (0x0f0f >> (4 - shift));
|
---|
| 3345 | tmp |= (unsigned int)(g << shift);
|
---|
| 3346 | *sp = (png_byte)(tmp & 0xff);
|
---|
| 3347 | }
|
---|
| 3348 |
|
---|
| 3349 | if (shift == 0)
|
---|
| 3350 | {
|
---|
| 3351 | shift = 4;
|
---|
| 3352 | sp++;
|
---|
| 3353 | }
|
---|
| 3354 |
|
---|
| 3355 | else
|
---|
| 3356 | shift -= 4;
|
---|
| 3357 | }
|
---|
| 3358 | }
|
---|
| 3359 |
|
---|
| 3360 | else
|
---|
| 3361 | #endif
|
---|
| 3362 | {
|
---|
| 3363 | sp = row;
|
---|
| 3364 | shift = 4;
|
---|
| 3365 | for (i = 0; i < row_width; i++)
|
---|
| 3366 | {
|
---|
| 3367 | if ((png_uint_16)((*sp >> shift) & 0x0f)
|
---|
| 3368 | == png_ptr->trans_color.gray)
|
---|
| 3369 | {
|
---|
| 3370 | unsigned int tmp = *sp & (0x0f0f >> (4 - shift));
|
---|
| 3371 | tmp |=
|
---|
| 3372 | (unsigned int)(png_ptr->background.gray << shift);
|
---|
| 3373 | *sp = (png_byte)(tmp & 0xff);
|
---|
| 3374 | }
|
---|
| 3375 |
|
---|
| 3376 | if (shift == 0)
|
---|
| 3377 | {
|
---|
| 3378 | shift = 4;
|
---|
| 3379 | sp++;
|
---|
| 3380 | }
|
---|
| 3381 |
|
---|
| 3382 | else
|
---|
| 3383 | shift -= 4;
|
---|
| 3384 | }
|
---|
| 3385 | }
|
---|
| 3386 | break;
|
---|
| 3387 | }
|
---|
| 3388 |
|
---|
| 3389 | case 8:
|
---|
| 3390 | {
|
---|
| 3391 | #ifdef PNG_READ_GAMMA_SUPPORTED
|
---|
| 3392 | if (gamma_table != NULL)
|
---|
| 3393 | {
|
---|
| 3394 | sp = row;
|
---|
| 3395 | for (i = 0; i < row_width; i++, sp++)
|
---|
| 3396 | {
|
---|
| 3397 | if (*sp == png_ptr->trans_color.gray)
|
---|
| 3398 | *sp = (png_byte)png_ptr->background.gray;
|
---|
| 3399 |
|
---|
| 3400 | else
|
---|
| 3401 | *sp = gamma_table[*sp];
|
---|
| 3402 | }
|
---|
| 3403 | }
|
---|
| 3404 | else
|
---|
| 3405 | #endif
|
---|
| 3406 | {
|
---|
| 3407 | sp = row;
|
---|
| 3408 | for (i = 0; i < row_width; i++, sp++)
|
---|
| 3409 | {
|
---|
| 3410 | if (*sp == png_ptr->trans_color.gray)
|
---|
| 3411 | *sp = (png_byte)png_ptr->background.gray;
|
---|
| 3412 | }
|
---|
| 3413 | }
|
---|
| 3414 | break;
|
---|
| 3415 | }
|
---|
| 3416 |
|
---|
| 3417 | case 16:
|
---|
| 3418 | {
|
---|
| 3419 | #ifdef PNG_READ_GAMMA_SUPPORTED
|
---|
| 3420 | if (gamma_16 != NULL)
|
---|
| 3421 | {
|
---|
| 3422 | sp = row;
|
---|
| 3423 | for (i = 0; i < row_width; i++, sp += 2)
|
---|
| 3424 | {
|
---|
| 3425 | png_uint_16 v;
|
---|
| 3426 |
|
---|
| 3427 | v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
|
---|
| 3428 |
|
---|
| 3429 | if (v == png_ptr->trans_color.gray)
|
---|
| 3430 | {
|
---|
| 3431 | /* Background is already in screen gamma */
|
---|
| 3432 | *sp = (png_byte)((png_ptr->background.gray >> 8)
|
---|
| 3433 | & 0xff);
|
---|
| 3434 | *(sp + 1) = (png_byte)(png_ptr->background.gray
|
---|
| 3435 | & 0xff);
|
---|
| 3436 | }
|
---|
| 3437 |
|
---|
| 3438 | else
|
---|
| 3439 | {
|
---|
| 3440 | v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
|
---|
| 3441 | *sp = (png_byte)((v >> 8) & 0xff);
|
---|
| 3442 | *(sp + 1) = (png_byte)(v & 0xff);
|
---|
| 3443 | }
|
---|
| 3444 | }
|
---|
| 3445 | }
|
---|
| 3446 | else
|
---|
| 3447 | #endif
|
---|
| 3448 | {
|
---|
| 3449 | sp = row;
|
---|
| 3450 | for (i = 0; i < row_width; i++, sp += 2)
|
---|
| 3451 | {
|
---|
| 3452 | png_uint_16 v;
|
---|
| 3453 |
|
---|
| 3454 | v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
|
---|
| 3455 |
|
---|
| 3456 | if (v == png_ptr->trans_color.gray)
|
---|
| 3457 | {
|
---|
| 3458 | *sp = (png_byte)((png_ptr->background.gray >> 8)
|
---|
| 3459 | & 0xff);
|
---|
| 3460 | *(sp + 1) = (png_byte)(png_ptr->background.gray
|
---|
| 3461 | & 0xff);
|
---|
| 3462 | }
|
---|
| 3463 | }
|
---|
| 3464 | }
|
---|
| 3465 | break;
|
---|
| 3466 | }
|
---|
| 3467 |
|
---|
| 3468 | default:
|
---|
| 3469 | break;
|
---|
| 3470 | }
|
---|
| 3471 | break;
|
---|
| 3472 | }
|
---|
| 3473 |
|
---|
| 3474 | case PNG_COLOR_TYPE_RGB:
|
---|
| 3475 | {
|
---|
| 3476 | if (row_info->bit_depth == 8)
|
---|
| 3477 | {
|
---|
| 3478 | #ifdef PNG_READ_GAMMA_SUPPORTED
|
---|
| 3479 | if (gamma_table != NULL)
|
---|
| 3480 | {
|
---|
| 3481 | sp = row;
|
---|
| 3482 | for (i = 0; i < row_width; i++, sp += 3)
|
---|
| 3483 | {
|
---|
| 3484 | if (*sp == png_ptr->trans_color.red &&
|
---|
| 3485 | *(sp + 1) == png_ptr->trans_color.green &&
|
---|
| 3486 | *(sp + 2) == png_ptr->trans_color.blue)
|
---|
| 3487 | {
|
---|
| 3488 | *sp = (png_byte)png_ptr->background.red;
|
---|
| 3489 | *(sp + 1) = (png_byte)png_ptr->background.green;
|
---|
| 3490 | *(sp + 2) = (png_byte)png_ptr->background.blue;
|
---|
| 3491 | }
|
---|
| 3492 |
|
---|
| 3493 | else
|
---|
| 3494 | {
|
---|
| 3495 | *sp = gamma_table[*sp];
|
---|
| 3496 | *(sp + 1) = gamma_table[*(sp + 1)];
|
---|
| 3497 | *(sp + 2) = gamma_table[*(sp + 2)];
|
---|
| 3498 | }
|
---|
| 3499 | }
|
---|
| 3500 | }
|
---|
| 3501 | else
|
---|
| 3502 | #endif
|
---|
| 3503 | {
|
---|
| 3504 | sp = row;
|
---|
| 3505 | for (i = 0; i < row_width; i++, sp += 3)
|
---|
| 3506 | {
|
---|
| 3507 | if (*sp == png_ptr->trans_color.red &&
|
---|
| 3508 | *(sp + 1) == png_ptr->trans_color.green &&
|
---|
| 3509 | *(sp + 2) == png_ptr->trans_color.blue)
|
---|
| 3510 | {
|
---|
| 3511 | *sp = (png_byte)png_ptr->background.red;
|
---|
| 3512 | *(sp + 1) = (png_byte)png_ptr->background.green;
|
---|
| 3513 | *(sp + 2) = (png_byte)png_ptr->background.blue;
|
---|
| 3514 | }
|
---|
| 3515 | }
|
---|
| 3516 | }
|
---|
| 3517 | }
|
---|
| 3518 | else /* if (row_info->bit_depth == 16) */
|
---|
| 3519 | {
|
---|
| 3520 | #ifdef PNG_READ_GAMMA_SUPPORTED
|
---|
| 3521 | if (gamma_16 != NULL)
|
---|
| 3522 | {
|
---|
| 3523 | sp = row;
|
---|
| 3524 | for (i = 0; i < row_width; i++, sp += 6)
|
---|
| 3525 | {
|
---|
| 3526 | png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
|
---|
| 3527 |
|
---|
| 3528 | png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
|
---|
| 3529 | + *(sp + 3));
|
---|
| 3530 |
|
---|
| 3531 | png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
|
---|
| 3532 | + *(sp + 5));
|
---|
| 3533 |
|
---|
| 3534 | if (r == png_ptr->trans_color.red &&
|
---|
| 3535 | g == png_ptr->trans_color.green &&
|
---|
| 3536 | b == png_ptr->trans_color.blue)
|
---|
| 3537 | {
|
---|
| 3538 | /* Background is already in screen gamma */
|
---|
| 3539 | *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
|
---|
| 3540 | *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
|
---|
| 3541 | *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
|
---|
| 3542 | & 0xff);
|
---|
| 3543 | *(sp + 3) = (png_byte)(png_ptr->background.green
|
---|
| 3544 | & 0xff);
|
---|
| 3545 | *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
|
---|
| 3546 | & 0xff);
|
---|
| 3547 | *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
|
---|
| 3548 | }
|
---|
| 3549 |
|
---|
| 3550 | else
|
---|
| 3551 | {
|
---|
| 3552 | png_uint_16 v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
|
---|
| 3553 | *sp = (png_byte)((v >> 8) & 0xff);
|
---|
| 3554 | *(sp + 1) = (png_byte)(v & 0xff);
|
---|
| 3555 |
|
---|
| 3556 | v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
|
---|
| 3557 | *(sp + 2) = (png_byte)((v >> 8) & 0xff);
|
---|
| 3558 | *(sp + 3) = (png_byte)(v & 0xff);
|
---|
| 3559 |
|
---|
| 3560 | v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
|
---|
| 3561 | *(sp + 4) = (png_byte)((v >> 8) & 0xff);
|
---|
| 3562 | *(sp + 5) = (png_byte)(v & 0xff);
|
---|
| 3563 | }
|
---|
| 3564 | }
|
---|
| 3565 | }
|
---|
| 3566 |
|
---|
| 3567 | else
|
---|
| 3568 | #endif
|
---|
| 3569 | {
|
---|
| 3570 | sp = row;
|
---|
| 3571 | for (i = 0; i < row_width; i++, sp += 6)
|
---|
| 3572 | {
|
---|
| 3573 | png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
|
---|
| 3574 |
|
---|
| 3575 | png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
|
---|
| 3576 | + *(sp + 3));
|
---|
| 3577 |
|
---|
| 3578 | png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
|
---|
| 3579 | + *(sp + 5));
|
---|
| 3580 |
|
---|
| 3581 | if (r == png_ptr->trans_color.red &&
|
---|
| 3582 | g == png_ptr->trans_color.green &&
|
---|
| 3583 | b == png_ptr->trans_color.blue)
|
---|
| 3584 | {
|
---|
| 3585 | *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
|
---|
| 3586 | *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
|
---|
| 3587 | *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
|
---|
| 3588 | & 0xff);
|
---|
| 3589 | *(sp + 3) = (png_byte)(png_ptr->background.green
|
---|
| 3590 | & 0xff);
|
---|
| 3591 | *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
|
---|
| 3592 | & 0xff);
|
---|
| 3593 | *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
|
---|
| 3594 | }
|
---|
| 3595 | }
|
---|
| 3596 | }
|
---|
| 3597 | }
|
---|
| 3598 | break;
|
---|
| 3599 | }
|
---|
| 3600 |
|
---|
| 3601 | case PNG_COLOR_TYPE_GRAY_ALPHA:
|
---|
| 3602 | {
|
---|
| 3603 | if (row_info->bit_depth == 8)
|
---|
| 3604 | {
|
---|
| 3605 | #ifdef PNG_READ_GAMMA_SUPPORTED
|
---|
| 3606 | if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
|
---|
| 3607 | gamma_table != NULL)
|
---|
| 3608 | {
|
---|
| 3609 | sp = row;
|
---|
| 3610 | for (i = 0; i < row_width; i++, sp += 2)
|
---|
| 3611 | {
|
---|
| 3612 | png_uint_16 a = *(sp + 1);
|
---|
| 3613 |
|
---|
| 3614 | if (a == 0xff)
|
---|
| 3615 | *sp = gamma_table[*sp];
|
---|
| 3616 |
|
---|
| 3617 | else if (a == 0)
|
---|
| 3618 | {
|
---|
| 3619 | /* Background is already in screen gamma */
|
---|
| 3620 | *sp = (png_byte)png_ptr->background.gray;
|
---|
| 3621 | }
|
---|
| 3622 |
|
---|
| 3623 | else
|
---|
| 3624 | {
|
---|
| 3625 | png_byte v, w;
|
---|
| 3626 |
|
---|
| 3627 | v = gamma_to_1[*sp];
|
---|
| 3628 | png_composite(w, v, a, png_ptr->background_1.gray);
|
---|
| 3629 | if (optimize == 0)
|
---|
| 3630 | w = gamma_from_1[w];
|
---|
| 3631 | *sp = w;
|
---|
| 3632 | }
|
---|
| 3633 | }
|
---|
| 3634 | }
|
---|
| 3635 | else
|
---|
| 3636 | #endif
|
---|
| 3637 | {
|
---|
| 3638 | sp = row;
|
---|
| 3639 | for (i = 0; i < row_width; i++, sp += 2)
|
---|
| 3640 | {
|
---|
| 3641 | png_byte a = *(sp + 1);
|
---|
| 3642 |
|
---|
| 3643 | if (a == 0)
|
---|
| 3644 | *sp = (png_byte)png_ptr->background.gray;
|
---|
| 3645 |
|
---|
| 3646 | else if (a < 0xff)
|
---|
| 3647 | png_composite(*sp, *sp, a, png_ptr->background.gray);
|
---|
| 3648 | }
|
---|
| 3649 | }
|
---|
| 3650 | }
|
---|
| 3651 | else /* if (png_ptr->bit_depth == 16) */
|
---|
| 3652 | {
|
---|
| 3653 | #ifdef PNG_READ_GAMMA_SUPPORTED
|
---|
| 3654 | if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
|
---|
| 3655 | gamma_16_to_1 != NULL)
|
---|
| 3656 | {
|
---|
| 3657 | sp = row;
|
---|
| 3658 | for (i = 0; i < row_width; i++, sp += 4)
|
---|
| 3659 | {
|
---|
| 3660 | png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8)
|
---|
| 3661 | + *(sp + 3));
|
---|
| 3662 |
|
---|
| 3663 | if (a == (png_uint_16)0xffff)
|
---|
| 3664 | {
|
---|
| 3665 | png_uint_16 v;
|
---|
| 3666 |
|
---|
| 3667 | v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
|
---|
| 3668 | *sp = (png_byte)((v >> 8) & 0xff);
|
---|
| 3669 | *(sp + 1) = (png_byte)(v & 0xff);
|
---|
| 3670 | }
|
---|
| 3671 |
|
---|
| 3672 | else if (a == 0)
|
---|
| 3673 | {
|
---|
| 3674 | /* Background is already in screen gamma */
|
---|
| 3675 | *sp = (png_byte)((png_ptr->background.gray >> 8)
|
---|
| 3676 | & 0xff);
|
---|
| 3677 | *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
|
---|
| 3678 | }
|
---|
| 3679 |
|
---|
| 3680 | else
|
---|
| 3681 | {
|
---|
| 3682 | png_uint_16 g, v, w;
|
---|
| 3683 |
|
---|
| 3684 | g = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
|
---|
| 3685 | png_composite_16(v, g, a, png_ptr->background_1.gray);
|
---|
| 3686 | if (optimize != 0)
|
---|
| 3687 | w = v;
|
---|
| 3688 | else
|
---|
| 3689 | w = gamma_16_from_1[(v & 0xff) >>
|
---|
| 3690 | gamma_shift][v >> 8];
|
---|
| 3691 | *sp = (png_byte)((w >> 8) & 0xff);
|
---|
| 3692 | *(sp + 1) = (png_byte)(w & 0xff);
|
---|
| 3693 | }
|
---|
| 3694 | }
|
---|
| 3695 | }
|
---|
| 3696 | else
|
---|
| 3697 | #endif
|
---|
| 3698 | {
|
---|
| 3699 | sp = row;
|
---|
| 3700 | for (i = 0; i < row_width; i++, sp += 4)
|
---|
| 3701 | {
|
---|
| 3702 | png_uint_16 a = (png_uint_16)(((*(sp + 2)) << 8)
|
---|
| 3703 | + *(sp + 3));
|
---|
| 3704 |
|
---|
| 3705 | if (a == 0)
|
---|
| 3706 | {
|
---|
| 3707 | *sp = (png_byte)((png_ptr->background.gray >> 8)
|
---|
| 3708 | & 0xff);
|
---|
| 3709 | *(sp + 1) = (png_byte)(png_ptr->background.gray & 0xff);
|
---|
| 3710 | }
|
---|
| 3711 |
|
---|
| 3712 | else if (a < 0xffff)
|
---|
| 3713 | {
|
---|
| 3714 | png_uint_16 g, v;
|
---|
| 3715 |
|
---|
| 3716 | g = (png_uint_16)(((*sp) << 8) + *(sp + 1));
|
---|
| 3717 | png_composite_16(v, g, a, png_ptr->background.gray);
|
---|
| 3718 | *sp = (png_byte)((v >> 8) & 0xff);
|
---|
| 3719 | *(sp + 1) = (png_byte)(v & 0xff);
|
---|
| 3720 | }
|
---|
| 3721 | }
|
---|
| 3722 | }
|
---|
| 3723 | }
|
---|
| 3724 | break;
|
---|
| 3725 | }
|
---|
| 3726 |
|
---|
| 3727 | case PNG_COLOR_TYPE_RGB_ALPHA:
|
---|
| 3728 | {
|
---|
| 3729 | if (row_info->bit_depth == 8)
|
---|
| 3730 | {
|
---|
| 3731 | #ifdef PNG_READ_GAMMA_SUPPORTED
|
---|
| 3732 | if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
|
---|
| 3733 | gamma_table != NULL)
|
---|
| 3734 | {
|
---|
| 3735 | sp = row;
|
---|
| 3736 | for (i = 0; i < row_width; i++, sp += 4)
|
---|
| 3737 | {
|
---|
| 3738 | png_byte a = *(sp + 3);
|
---|
| 3739 |
|
---|
| 3740 | if (a == 0xff)
|
---|
| 3741 | {
|
---|
| 3742 | *sp = gamma_table[*sp];
|
---|
| 3743 | *(sp + 1) = gamma_table[*(sp + 1)];
|
---|
| 3744 | *(sp + 2) = gamma_table[*(sp + 2)];
|
---|
| 3745 | }
|
---|
| 3746 |
|
---|
| 3747 | else if (a == 0)
|
---|
| 3748 | {
|
---|
| 3749 | /* Background is already in screen gamma */
|
---|
| 3750 | *sp = (png_byte)png_ptr->background.red;
|
---|
| 3751 | *(sp + 1) = (png_byte)png_ptr->background.green;
|
---|
| 3752 | *(sp + 2) = (png_byte)png_ptr->background.blue;
|
---|
| 3753 | }
|
---|
| 3754 |
|
---|
| 3755 | else
|
---|
| 3756 | {
|
---|
| 3757 | png_byte v, w;
|
---|
| 3758 |
|
---|
| 3759 | v = gamma_to_1[*sp];
|
---|
| 3760 | png_composite(w, v, a, png_ptr->background_1.red);
|
---|
| 3761 | if (optimize == 0) w = gamma_from_1[w];
|
---|
| 3762 | *sp = w;
|
---|
| 3763 |
|
---|
| 3764 | v = gamma_to_1[*(sp + 1)];
|
---|
| 3765 | png_composite(w, v, a, png_ptr->background_1.green);
|
---|
| 3766 | if (optimize == 0) w = gamma_from_1[w];
|
---|
| 3767 | *(sp + 1) = w;
|
---|
| 3768 |
|
---|
| 3769 | v = gamma_to_1[*(sp + 2)];
|
---|
| 3770 | png_composite(w, v, a, png_ptr->background_1.blue);
|
---|
| 3771 | if (optimize == 0) w = gamma_from_1[w];
|
---|
| 3772 | *(sp + 2) = w;
|
---|
| 3773 | }
|
---|
| 3774 | }
|
---|
| 3775 | }
|
---|
| 3776 | else
|
---|
| 3777 | #endif
|
---|
| 3778 | {
|
---|
| 3779 | sp = row;
|
---|
| 3780 | for (i = 0; i < row_width; i++, sp += 4)
|
---|
| 3781 | {
|
---|
| 3782 | png_byte a = *(sp + 3);
|
---|
| 3783 |
|
---|
| 3784 | if (a == 0)
|
---|
| 3785 | {
|
---|
| 3786 | *sp = (png_byte)png_ptr->background.red;
|
---|
| 3787 | *(sp + 1) = (png_byte)png_ptr->background.green;
|
---|
| 3788 | *(sp + 2) = (png_byte)png_ptr->background.blue;
|
---|
| 3789 | }
|
---|
| 3790 |
|
---|
| 3791 | else if (a < 0xff)
|
---|
| 3792 | {
|
---|
| 3793 | png_composite(*sp, *sp, a, png_ptr->background.red);
|
---|
| 3794 |
|
---|
| 3795 | png_composite(*(sp + 1), *(sp + 1), a,
|
---|
| 3796 | png_ptr->background.green);
|
---|
| 3797 |
|
---|
| 3798 | png_composite(*(sp + 2), *(sp + 2), a,
|
---|
| 3799 | png_ptr->background.blue);
|
---|
| 3800 | }
|
---|
| 3801 | }
|
---|
| 3802 | }
|
---|
| 3803 | }
|
---|
| 3804 | else /* if (row_info->bit_depth == 16) */
|
---|
| 3805 | {
|
---|
| 3806 | #ifdef PNG_READ_GAMMA_SUPPORTED
|
---|
| 3807 | if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
|
---|
| 3808 | gamma_16_to_1 != NULL)
|
---|
| 3809 | {
|
---|
| 3810 | sp = row;
|
---|
| 3811 | for (i = 0; i < row_width; i++, sp += 8)
|
---|
| 3812 | {
|
---|
| 3813 | png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
|
---|
| 3814 | << 8) + (png_uint_16)(*(sp + 7)));
|
---|
| 3815 |
|
---|
| 3816 | if (a == (png_uint_16)0xffff)
|
---|
| 3817 | {
|
---|
| 3818 | png_uint_16 v;
|
---|
| 3819 |
|
---|
| 3820 | v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
|
---|
| 3821 | *sp = (png_byte)((v >> 8) & 0xff);
|
---|
| 3822 | *(sp + 1) = (png_byte)(v & 0xff);
|
---|
| 3823 |
|
---|
| 3824 | v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
|
---|
| 3825 | *(sp + 2) = (png_byte)((v >> 8) & 0xff);
|
---|
| 3826 | *(sp + 3) = (png_byte)(v & 0xff);
|
---|
| 3827 |
|
---|
| 3828 | v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
|
---|
| 3829 | *(sp + 4) = (png_byte)((v >> 8) & 0xff);
|
---|
| 3830 | *(sp + 5) = (png_byte)(v & 0xff);
|
---|
| 3831 | }
|
---|
| 3832 |
|
---|
| 3833 | else if (a == 0)
|
---|
| 3834 | {
|
---|
| 3835 | /* Background is already in screen gamma */
|
---|
| 3836 | *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
|
---|
| 3837 | *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
|
---|
| 3838 | *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
|
---|
| 3839 | & 0xff);
|
---|
| 3840 | *(sp + 3) = (png_byte)(png_ptr->background.green
|
---|
| 3841 | & 0xff);
|
---|
| 3842 | *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
|
---|
| 3843 | & 0xff);
|
---|
| 3844 | *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
|
---|
| 3845 | }
|
---|
| 3846 |
|
---|
| 3847 | else
|
---|
| 3848 | {
|
---|
| 3849 | png_uint_16 v, w;
|
---|
| 3850 |
|
---|
| 3851 | v = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
|
---|
| 3852 | png_composite_16(w, v, a, png_ptr->background_1.red);
|
---|
| 3853 | if (optimize == 0)
|
---|
| 3854 | w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
|
---|
| 3855 | 8];
|
---|
| 3856 | *sp = (png_byte)((w >> 8) & 0xff);
|
---|
| 3857 | *(sp + 1) = (png_byte)(w & 0xff);
|
---|
| 3858 |
|
---|
| 3859 | v = gamma_16_to_1[*(sp + 3) >> gamma_shift][*(sp + 2)];
|
---|
| 3860 | png_composite_16(w, v, a, png_ptr->background_1.green);
|
---|
| 3861 | if (optimize == 0)
|
---|
| 3862 | w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
|
---|
| 3863 | 8];
|
---|
| 3864 |
|
---|
| 3865 | *(sp + 2) = (png_byte)((w >> 8) & 0xff);
|
---|
| 3866 | *(sp + 3) = (png_byte)(w & 0xff);
|
---|
| 3867 |
|
---|
| 3868 | v = gamma_16_to_1[*(sp + 5) >> gamma_shift][*(sp + 4)];
|
---|
| 3869 | png_composite_16(w, v, a, png_ptr->background_1.blue);
|
---|
| 3870 | if (optimize == 0)
|
---|
| 3871 | w = gamma_16_from_1[((w & 0xff) >> gamma_shift)][w >>
|
---|
| 3872 | 8];
|
---|
| 3873 |
|
---|
| 3874 | *(sp + 4) = (png_byte)((w >> 8) & 0xff);
|
---|
| 3875 | *(sp + 5) = (png_byte)(w & 0xff);
|
---|
| 3876 | }
|
---|
| 3877 | }
|
---|
| 3878 | }
|
---|
| 3879 |
|
---|
| 3880 | else
|
---|
| 3881 | #endif
|
---|
| 3882 | {
|
---|
| 3883 | sp = row;
|
---|
| 3884 | for (i = 0; i < row_width; i++, sp += 8)
|
---|
| 3885 | {
|
---|
| 3886 | png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
|
---|
| 3887 | << 8) + (png_uint_16)(*(sp + 7)));
|
---|
| 3888 |
|
---|
| 3889 | if (a == 0)
|
---|
| 3890 | {
|
---|
| 3891 | *sp = (png_byte)((png_ptr->background.red >> 8) & 0xff);
|
---|
| 3892 | *(sp + 1) = (png_byte)(png_ptr->background.red & 0xff);
|
---|
| 3893 | *(sp + 2) = (png_byte)((png_ptr->background.green >> 8)
|
---|
| 3894 | & 0xff);
|
---|
| 3895 | *(sp + 3) = (png_byte)(png_ptr->background.green
|
---|
| 3896 | & 0xff);
|
---|
| 3897 | *(sp + 4) = (png_byte)((png_ptr->background.blue >> 8)
|
---|
| 3898 | & 0xff);
|
---|
| 3899 | *(sp + 5) = (png_byte)(png_ptr->background.blue & 0xff);
|
---|
| 3900 | }
|
---|
| 3901 |
|
---|
| 3902 | else if (a < 0xffff)
|
---|
| 3903 | {
|
---|
| 3904 | png_uint_16 v;
|
---|
| 3905 |
|
---|
| 3906 | png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
|
---|
| 3907 | png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
|
---|
| 3908 | + *(sp + 3));
|
---|
| 3909 | png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
|
---|
| 3910 | + *(sp + 5));
|
---|
| 3911 |
|
---|
| 3912 | png_composite_16(v, r, a, png_ptr->background.red);
|
---|
| 3913 | *sp = (png_byte)((v >> 8) & 0xff);
|
---|
| 3914 | *(sp + 1) = (png_byte)(v & 0xff);
|
---|
| 3915 |
|
---|
| 3916 | png_composite_16(v, g, a, png_ptr->background.green);
|
---|
| 3917 | *(sp + 2) = (png_byte)((v >> 8) & 0xff);
|
---|
| 3918 | *(sp + 3) = (png_byte)(v & 0xff);
|
---|
| 3919 |
|
---|
| 3920 | png_composite_16(v, b, a, png_ptr->background.blue);
|
---|
| 3921 | *(sp + 4) = (png_byte)((v >> 8) & 0xff);
|
---|
| 3922 | *(sp + 5) = (png_byte)(v & 0xff);
|
---|
| 3923 | }
|
---|
| 3924 | }
|
---|
| 3925 | }
|
---|
| 3926 | }
|
---|
| 3927 | break;
|
---|
| 3928 | }
|
---|
| 3929 |
|
---|
| 3930 | default:
|
---|
| 3931 | break;
|
---|
| 3932 | }
|
---|
| 3933 | }
|
---|
| 3934 | #endif /* READ_BACKGROUND || READ_ALPHA_MODE */
|
---|
| 3935 |
|
---|
| 3936 | #ifdef PNG_READ_GAMMA_SUPPORTED
|
---|
| 3937 | /* Gamma correct the image, avoiding the alpha channel. Make sure
|
---|
| 3938 | * you do this after you deal with the transparency issue on grayscale
|
---|
| 3939 | * or RGB images. If your bit depth is 8, use gamma_table, if it
|
---|
| 3940 | * is 16, use gamma_16_table and gamma_shift. Build these with
|
---|
| 3941 | * build_gamma_table().
|
---|
| 3942 | */
|
---|
| 3943 | static void
|
---|
| 3944 | png_do_gamma(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
|
---|
| 3945 | {
|
---|
| 3946 | png_const_bytep gamma_table = png_ptr->gamma_table;
|
---|
| 3947 | png_const_uint_16pp gamma_16_table = png_ptr->gamma_16_table;
|
---|
| 3948 | int gamma_shift = png_ptr->gamma_shift;
|
---|
| 3949 |
|
---|
| 3950 | png_bytep sp;
|
---|
| 3951 | png_uint_32 i;
|
---|
| 3952 | png_uint_32 row_width=row_info->width;
|
---|
| 3953 |
|
---|
| 3954 | png_debug(1, "in png_do_gamma");
|
---|
| 3955 |
|
---|
| 3956 | if (((row_info->bit_depth <= 8 && gamma_table != NULL) ||
|
---|
| 3957 | (row_info->bit_depth == 16 && gamma_16_table != NULL)))
|
---|
| 3958 | {
|
---|
| 3959 | switch (row_info->color_type)
|
---|
| 3960 | {
|
---|
| 3961 | case PNG_COLOR_TYPE_RGB:
|
---|
| 3962 | {
|
---|
| 3963 | if (row_info->bit_depth == 8)
|
---|
| 3964 | {
|
---|
| 3965 | sp = row;
|
---|
| 3966 | for (i = 0; i < row_width; i++)
|
---|
| 3967 | {
|
---|
| 3968 | *sp = gamma_table[*sp];
|
---|
| 3969 | sp++;
|
---|
| 3970 | *sp = gamma_table[*sp];
|
---|
| 3971 | sp++;
|
---|
| 3972 | *sp = gamma_table[*sp];
|
---|
| 3973 | sp++;
|
---|
| 3974 | }
|
---|
| 3975 | }
|
---|
| 3976 |
|
---|
| 3977 | else /* if (row_info->bit_depth == 16) */
|
---|
| 3978 | {
|
---|
| 3979 | sp = row;
|
---|
| 3980 | for (i = 0; i < row_width; i++)
|
---|
| 3981 | {
|
---|
| 3982 | png_uint_16 v;
|
---|
| 3983 |
|
---|
| 3984 | v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
|
---|
| 3985 | *sp = (png_byte)((v >> 8) & 0xff);
|
---|
| 3986 | *(sp + 1) = (png_byte)(v & 0xff);
|
---|
| 3987 | sp += 2;
|
---|
| 3988 |
|
---|
| 3989 | v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
|
---|
| 3990 | *sp = (png_byte)((v >> 8) & 0xff);
|
---|
| 3991 | *(sp + 1) = (png_byte)(v & 0xff);
|
---|
| 3992 | sp += 2;
|
---|
| 3993 |
|
---|
| 3994 | v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
|
---|
| 3995 | *sp = (png_byte)((v >> 8) & 0xff);
|
---|
| 3996 | *(sp + 1) = (png_byte)(v & 0xff);
|
---|
| 3997 | sp += 2;
|
---|
| 3998 | }
|
---|
| 3999 | }
|
---|
| 4000 | break;
|
---|
| 4001 | }
|
---|
| 4002 |
|
---|
| 4003 | case PNG_COLOR_TYPE_RGB_ALPHA:
|
---|
| 4004 | {
|
---|
| 4005 | if (row_info->bit_depth == 8)
|
---|
| 4006 | {
|
---|
| 4007 | sp = row;
|
---|
| 4008 | for (i = 0; i < row_width; i++)
|
---|
| 4009 | {
|
---|
| 4010 | *sp = gamma_table[*sp];
|
---|
| 4011 | sp++;
|
---|
| 4012 |
|
---|
| 4013 | *sp = gamma_table[*sp];
|
---|
| 4014 | sp++;
|
---|
| 4015 |
|
---|
| 4016 | *sp = gamma_table[*sp];
|
---|
| 4017 | sp++;
|
---|
| 4018 |
|
---|
| 4019 | sp++;
|
---|
| 4020 | }
|
---|
| 4021 | }
|
---|
| 4022 |
|
---|
| 4023 | else /* if (row_info->bit_depth == 16) */
|
---|
| 4024 | {
|
---|
| 4025 | sp = row;
|
---|
| 4026 | for (i = 0; i < row_width; i++)
|
---|
| 4027 | {
|
---|
| 4028 | png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
|
---|
| 4029 | *sp = (png_byte)((v >> 8) & 0xff);
|
---|
| 4030 | *(sp + 1) = (png_byte)(v & 0xff);
|
---|
| 4031 | sp += 2;
|
---|
| 4032 |
|
---|
| 4033 | v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
|
---|
| 4034 | *sp = (png_byte)((v >> 8) & 0xff);
|
---|
| 4035 | *(sp + 1) = (png_byte)(v & 0xff);
|
---|
| 4036 | sp += 2;
|
---|
| 4037 |
|
---|
| 4038 | v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
|
---|
| 4039 | *sp = (png_byte)((v >> 8) & 0xff);
|
---|
| 4040 | *(sp + 1) = (png_byte)(v & 0xff);
|
---|
| 4041 | sp += 4;
|
---|
| 4042 | }
|
---|
| 4043 | }
|
---|
| 4044 | break;
|
---|
| 4045 | }
|
---|
| 4046 |
|
---|
| 4047 | case PNG_COLOR_TYPE_GRAY_ALPHA:
|
---|
| 4048 | {
|
---|
| 4049 | if (row_info->bit_depth == 8)
|
---|
| 4050 | {
|
---|
| 4051 | sp = row;
|
---|
| 4052 | for (i = 0; i < row_width; i++)
|
---|
| 4053 | {
|
---|
| 4054 | *sp = gamma_table[*sp];
|
---|
| 4055 | sp += 2;
|
---|
| 4056 | }
|
---|
| 4057 | }
|
---|
| 4058 |
|
---|
| 4059 | else /* if (row_info->bit_depth == 16) */
|
---|
| 4060 | {
|
---|
| 4061 | sp = row;
|
---|
| 4062 | for (i = 0; i < row_width; i++)
|
---|
| 4063 | {
|
---|
| 4064 | png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
|
---|
| 4065 | *sp = (png_byte)((v >> 8) & 0xff);
|
---|
| 4066 | *(sp + 1) = (png_byte)(v & 0xff);
|
---|
| 4067 | sp += 4;
|
---|
| 4068 | }
|
---|
| 4069 | }
|
---|
| 4070 | break;
|
---|
| 4071 | }
|
---|
| 4072 |
|
---|
| 4073 | case PNG_COLOR_TYPE_GRAY:
|
---|
| 4074 | {
|
---|
| 4075 | if (row_info->bit_depth == 2)
|
---|
| 4076 | {
|
---|
| 4077 | sp = row;
|
---|
| 4078 | for (i = 0; i < row_width; i += 4)
|
---|
| 4079 | {
|
---|
| 4080 | int a = *sp & 0xc0;
|
---|
| 4081 | int b = *sp & 0x30;
|
---|
| 4082 | int c = *sp & 0x0c;
|
---|
| 4083 | int d = *sp & 0x03;
|
---|
| 4084 |
|
---|
| 4085 | *sp = (png_byte)(
|
---|
| 4086 | ((((int)gamma_table[a|(a>>2)|(a>>4)|(a>>6)]) ) & 0xc0)|
|
---|
| 4087 | ((((int)gamma_table[(b<<2)|b|(b>>2)|(b>>4)])>>2) & 0x30)|
|
---|
| 4088 | ((((int)gamma_table[(c<<4)|(c<<2)|c|(c>>2)])>>4) & 0x0c)|
|
---|
| 4089 | ((((int)gamma_table[(d<<6)|(d<<4)|(d<<2)|d])>>6) ));
|
---|
| 4090 | sp++;
|
---|
| 4091 | }
|
---|
| 4092 | }
|
---|
| 4093 |
|
---|
| 4094 | if (row_info->bit_depth == 4)
|
---|
| 4095 | {
|
---|
| 4096 | sp = row;
|
---|
| 4097 | for (i = 0; i < row_width; i += 2)
|
---|
| 4098 | {
|
---|
| 4099 | int msb = *sp & 0xf0;
|
---|
| 4100 | int lsb = *sp & 0x0f;
|
---|
| 4101 |
|
---|
| 4102 | *sp = (png_byte)((((int)gamma_table[msb | (msb >> 4)]) & 0xf0)
|
---|
| 4103 | | (((int)gamma_table[(lsb << 4) | lsb]) >> 4));
|
---|
| 4104 | sp++;
|
---|
| 4105 | }
|
---|
| 4106 | }
|
---|
| 4107 |
|
---|
| 4108 | else if (row_info->bit_depth == 8)
|
---|
| 4109 | {
|
---|
| 4110 | sp = row;
|
---|
| 4111 | for (i = 0; i < row_width; i++)
|
---|
| 4112 | {
|
---|
| 4113 | *sp = gamma_table[*sp];
|
---|
| 4114 | sp++;
|
---|
| 4115 | }
|
---|
| 4116 | }
|
---|
| 4117 |
|
---|
| 4118 | else if (row_info->bit_depth == 16)
|
---|
| 4119 | {
|
---|
| 4120 | sp = row;
|
---|
| 4121 | for (i = 0; i < row_width; i++)
|
---|
| 4122 | {
|
---|
| 4123 | png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
|
---|
| 4124 | *sp = (png_byte)((v >> 8) & 0xff);
|
---|
| 4125 | *(sp + 1) = (png_byte)(v & 0xff);
|
---|
| 4126 | sp += 2;
|
---|
| 4127 | }
|
---|
| 4128 | }
|
---|
| 4129 | break;
|
---|
| 4130 | }
|
---|
| 4131 |
|
---|
| 4132 | default:
|
---|
| 4133 | break;
|
---|
| 4134 | }
|
---|
| 4135 | }
|
---|
| 4136 | }
|
---|
| 4137 | #endif
|
---|
| 4138 |
|
---|
| 4139 | #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
|
---|
| 4140 | /* Encode the alpha channel to the output gamma (the input channel is always
|
---|
| 4141 | * linear.) Called only with color types that have an alpha channel. Needs the
|
---|
| 4142 | * from_1 tables.
|
---|
| 4143 | */
|
---|
| 4144 | static void
|
---|
| 4145 | png_do_encode_alpha(png_row_infop row_info, png_bytep row, png_structrp png_ptr)
|
---|
| 4146 | {
|
---|
| 4147 | png_uint_32 row_width = row_info->width;
|
---|
| 4148 |
|
---|
| 4149 | png_debug(1, "in png_do_encode_alpha");
|
---|
| 4150 |
|
---|
| 4151 | if ((row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0)
|
---|
| 4152 | {
|
---|
| 4153 | if (row_info->bit_depth == 8)
|
---|
| 4154 | {
|
---|
| 4155 | png_bytep table = png_ptr->gamma_from_1;
|
---|
| 4156 |
|
---|
| 4157 | if (table != NULL)
|
---|
| 4158 | {
|
---|
| 4159 | int step = (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 4 : 2;
|
---|
| 4160 |
|
---|
| 4161 | /* The alpha channel is the last component: */
|
---|
| 4162 | row += step - 1;
|
---|
| 4163 |
|
---|
| 4164 | for (; row_width > 0; --row_width, row += step)
|
---|
| 4165 | *row = table[*row];
|
---|
| 4166 |
|
---|
| 4167 | return;
|
---|
| 4168 | }
|
---|
| 4169 | }
|
---|
| 4170 |
|
---|
| 4171 | else if (row_info->bit_depth == 16)
|
---|
| 4172 | {
|
---|
| 4173 | png_uint_16pp table = png_ptr->gamma_16_from_1;
|
---|
| 4174 | int gamma_shift = png_ptr->gamma_shift;
|
---|
| 4175 |
|
---|
| 4176 | if (table != NULL)
|
---|
| 4177 | {
|
---|
| 4178 | int step = (row_info->color_type & PNG_COLOR_MASK_COLOR) ? 8 : 4;
|
---|
| 4179 |
|
---|
| 4180 | /* The alpha channel is the last component: */
|
---|
| 4181 | row += step - 2;
|
---|
| 4182 |
|
---|
| 4183 | for (; row_width > 0; --row_width, row += step)
|
---|
| 4184 | {
|
---|
| 4185 | png_uint_16 v;
|
---|
| 4186 |
|
---|
| 4187 | v = table[*(row + 1) >> gamma_shift][*row];
|
---|
| 4188 | *row = (png_byte)((v >> 8) & 0xff);
|
---|
| 4189 | *(row + 1) = (png_byte)(v & 0xff);
|
---|
| 4190 | }
|
---|
| 4191 |
|
---|
| 4192 | return;
|
---|
| 4193 | }
|
---|
| 4194 | }
|
---|
| 4195 | }
|
---|
| 4196 |
|
---|
| 4197 | /* Only get to here if called with a weird row_info; no harm has been done,
|
---|
| 4198 | * so just issue a warning.
|
---|
| 4199 | */
|
---|
| 4200 | png_warning(png_ptr, "png_do_encode_alpha: unexpected call");
|
---|
| 4201 | }
|
---|
| 4202 | #endif
|
---|
| 4203 |
|
---|
| 4204 | #ifdef PNG_READ_EXPAND_SUPPORTED
|
---|
| 4205 | /* Expands a palette row to an RGB or RGBA row depending
|
---|
| 4206 | * upon whether you supply trans and num_trans.
|
---|
| 4207 | */
|
---|
| 4208 | static void
|
---|
| 4209 | png_do_expand_palette(png_structrp png_ptr, png_row_infop row_info,
|
---|
| 4210 | png_bytep row, png_const_colorp palette, png_const_bytep trans_alpha,
|
---|
| 4211 | int num_trans)
|
---|
| 4212 | {
|
---|
| 4213 | int shift, value;
|
---|
| 4214 | png_bytep sp, dp;
|
---|
| 4215 | png_uint_32 i;
|
---|
| 4216 | png_uint_32 row_width=row_info->width;
|
---|
| 4217 |
|
---|
| 4218 | png_debug(1, "in png_do_expand_palette");
|
---|
| 4219 |
|
---|
| 4220 | if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
|
---|
| 4221 | {
|
---|
| 4222 | if (row_info->bit_depth < 8)
|
---|
| 4223 | {
|
---|
| 4224 | switch (row_info->bit_depth)
|
---|
| 4225 | {
|
---|
| 4226 | case 1:
|
---|
| 4227 | {
|
---|
| 4228 | sp = row + (size_t)((row_width - 1) >> 3);
|
---|
| 4229 | dp = row + (size_t)row_width - 1;
|
---|
| 4230 | shift = 7 - (int)((row_width + 7) & 0x07);
|
---|
| 4231 | for (i = 0; i < row_width; i++)
|
---|
| 4232 | {
|
---|
| 4233 | if ((*sp >> shift) & 0x01)
|
---|
| 4234 | *dp = 1;
|
---|
| 4235 |
|
---|
| 4236 | else
|
---|
| 4237 | *dp = 0;
|
---|
| 4238 |
|
---|
| 4239 | if (shift == 7)
|
---|
| 4240 | {
|
---|
| 4241 | shift = 0;
|
---|
| 4242 | sp--;
|
---|
| 4243 | }
|
---|
| 4244 |
|
---|
| 4245 | else
|
---|
| 4246 | shift++;
|
---|
| 4247 |
|
---|
| 4248 | dp--;
|
---|
| 4249 | }
|
---|
| 4250 | break;
|
---|
| 4251 | }
|
---|
| 4252 |
|
---|
| 4253 | case 2:
|
---|
| 4254 | {
|
---|
| 4255 | sp = row + (size_t)((row_width - 1) >> 2);
|
---|
| 4256 | dp = row + (size_t)row_width - 1;
|
---|
| 4257 | shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
|
---|
| 4258 | for (i = 0; i < row_width; i++)
|
---|
| 4259 | {
|
---|
| 4260 | value = (*sp >> shift) & 0x03;
|
---|
| 4261 | *dp = (png_byte)value;
|
---|
| 4262 | if (shift == 6)
|
---|
| 4263 | {
|
---|
| 4264 | shift = 0;
|
---|
| 4265 | sp--;
|
---|
| 4266 | }
|
---|
| 4267 |
|
---|
| 4268 | else
|
---|
| 4269 | shift += 2;
|
---|
| 4270 |
|
---|
| 4271 | dp--;
|
---|
| 4272 | }
|
---|
| 4273 | break;
|
---|
| 4274 | }
|
---|
| 4275 |
|
---|
| 4276 | case 4:
|
---|
| 4277 | {
|
---|
| 4278 | sp = row + (size_t)((row_width - 1) >> 1);
|
---|
| 4279 | dp = row + (size_t)row_width - 1;
|
---|
| 4280 | shift = (int)((row_width & 0x01) << 2);
|
---|
| 4281 | for (i = 0; i < row_width; i++)
|
---|
| 4282 | {
|
---|
| 4283 | value = (*sp >> shift) & 0x0f;
|
---|
| 4284 | *dp = (png_byte)value;
|
---|
| 4285 | if (shift == 4)
|
---|
| 4286 | {
|
---|
| 4287 | shift = 0;
|
---|
| 4288 | sp--;
|
---|
| 4289 | }
|
---|
| 4290 |
|
---|
| 4291 | else
|
---|
| 4292 | shift += 4;
|
---|
| 4293 |
|
---|
| 4294 | dp--;
|
---|
| 4295 | }
|
---|
| 4296 | break;
|
---|
| 4297 | }
|
---|
| 4298 |
|
---|
| 4299 | default:
|
---|
| 4300 | break;
|
---|
| 4301 | }
|
---|
| 4302 | row_info->bit_depth = 8;
|
---|
| 4303 | row_info->pixel_depth = 8;
|
---|
| 4304 | row_info->rowbytes = row_width;
|
---|
| 4305 | }
|
---|
| 4306 |
|
---|
| 4307 | if (row_info->bit_depth == 8)
|
---|
| 4308 | {
|
---|
| 4309 | {
|
---|
| 4310 | if (num_trans > 0)
|
---|
| 4311 | {
|
---|
| 4312 | sp = row + (size_t)row_width - 1;
|
---|
| 4313 | dp = row + ((size_t)row_width << 2) - 1;
|
---|
| 4314 |
|
---|
| 4315 | i = 0;
|
---|
| 4316 | #ifdef PNG_ARM_NEON_INTRINSICS_AVAILABLE
|
---|
| 4317 | if (png_ptr->riffled_palette != NULL)
|
---|
| 4318 | {
|
---|
| 4319 | /* The RGBA optimization works with png_ptr->bit_depth == 8
|
---|
| 4320 | * but sometimes row_info->bit_depth has been changed to 8.
|
---|
| 4321 | * In these cases, the palette hasn't been riffled.
|
---|
| 4322 | */
|
---|
| 4323 | i = png_do_expand_palette_rgba8_neon(png_ptr, row_info, row,
|
---|
| 4324 | &sp, &dp);
|
---|
| 4325 | }
|
---|
| 4326 | #else
|
---|
| 4327 | PNG_UNUSED(png_ptr)
|
---|
| 4328 | #endif
|
---|
| 4329 |
|
---|
| 4330 | for (; i < row_width; i++)
|
---|
| 4331 | {
|
---|
| 4332 | if ((int)(*sp) >= num_trans)
|
---|
| 4333 | *dp-- = 0xff;
|
---|
| 4334 | else
|
---|
| 4335 | *dp-- = trans_alpha[*sp];
|
---|
| 4336 | *dp-- = palette[*sp].blue;
|
---|
| 4337 | *dp-- = palette[*sp].green;
|
---|
| 4338 | *dp-- = palette[*sp].red;
|
---|
| 4339 | sp--;
|
---|
| 4340 | }
|
---|
| 4341 | row_info->bit_depth = 8;
|
---|
| 4342 | row_info->pixel_depth = 32;
|
---|
| 4343 | row_info->rowbytes = row_width * 4;
|
---|
| 4344 | row_info->color_type = 6;
|
---|
| 4345 | row_info->channels = 4;
|
---|
| 4346 | }
|
---|
| 4347 |
|
---|
| 4348 | else
|
---|
| 4349 | {
|
---|
| 4350 | sp = row + (size_t)row_width - 1;
|
---|
| 4351 | dp = row + (size_t)(row_width * 3) - 1;
|
---|
| 4352 | i = 0;
|
---|
| 4353 | #ifdef PNG_ARM_NEON_INTRINSICS_AVAILABLE
|
---|
| 4354 | i = png_do_expand_palette_rgb8_neon(png_ptr, row_info, row,
|
---|
| 4355 | &sp, &dp);
|
---|
| 4356 | #else
|
---|
| 4357 | PNG_UNUSED(png_ptr)
|
---|
| 4358 | #endif
|
---|
| 4359 |
|
---|
| 4360 | for (; i < row_width; i++)
|
---|
| 4361 | {
|
---|
| 4362 | *dp-- = palette[*sp].blue;
|
---|
| 4363 | *dp-- = palette[*sp].green;
|
---|
| 4364 | *dp-- = palette[*sp].red;
|
---|
| 4365 | sp--;
|
---|
| 4366 | }
|
---|
| 4367 |
|
---|
| 4368 | row_info->bit_depth = 8;
|
---|
| 4369 | row_info->pixel_depth = 24;
|
---|
| 4370 | row_info->rowbytes = row_width * 3;
|
---|
| 4371 | row_info->color_type = 2;
|
---|
| 4372 | row_info->channels = 3;
|
---|
| 4373 | }
|
---|
| 4374 | }
|
---|
| 4375 | }
|
---|
| 4376 | }
|
---|
| 4377 | }
|
---|
| 4378 |
|
---|
| 4379 | /* If the bit depth < 8, it is expanded to 8. Also, if the already
|
---|
| 4380 | * expanded transparency value is supplied, an alpha channel is built.
|
---|
| 4381 | */
|
---|
| 4382 | static void
|
---|
| 4383 | png_do_expand(png_row_infop row_info, png_bytep row,
|
---|
| 4384 | png_const_color_16p trans_color)
|
---|
| 4385 | {
|
---|
| 4386 | int shift, value;
|
---|
| 4387 | png_bytep sp, dp;
|
---|
| 4388 | png_uint_32 i;
|
---|
| 4389 | png_uint_32 row_width=row_info->width;
|
---|
| 4390 |
|
---|
| 4391 | png_debug(1, "in png_do_expand");
|
---|
| 4392 |
|
---|
| 4393 | if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
|
---|
| 4394 | {
|
---|
| 4395 | unsigned int gray = trans_color != NULL ? trans_color->gray : 0;
|
---|
| 4396 |
|
---|
| 4397 | if (row_info->bit_depth < 8)
|
---|
| 4398 | {
|
---|
| 4399 | switch (row_info->bit_depth)
|
---|
| 4400 | {
|
---|
| 4401 | case 1:
|
---|
| 4402 | {
|
---|
| 4403 | gray = (gray & 0x01) * 0xff;
|
---|
| 4404 | sp = row + (size_t)((row_width - 1) >> 3);
|
---|
| 4405 | dp = row + (size_t)row_width - 1;
|
---|
| 4406 | shift = 7 - (int)((row_width + 7) & 0x07);
|
---|
| 4407 | for (i = 0; i < row_width; i++)
|
---|
| 4408 | {
|
---|
| 4409 | if ((*sp >> shift) & 0x01)
|
---|
| 4410 | *dp = 0xff;
|
---|
| 4411 |
|
---|
| 4412 | else
|
---|
| 4413 | *dp = 0;
|
---|
| 4414 |
|
---|
| 4415 | if (shift == 7)
|
---|
| 4416 | {
|
---|
| 4417 | shift = 0;
|
---|
| 4418 | sp--;
|
---|
| 4419 | }
|
---|
| 4420 |
|
---|
| 4421 | else
|
---|
| 4422 | shift++;
|
---|
| 4423 |
|
---|
| 4424 | dp--;
|
---|
| 4425 | }
|
---|
| 4426 | break;
|
---|
| 4427 | }
|
---|
| 4428 |
|
---|
| 4429 | case 2:
|
---|
| 4430 | {
|
---|
| 4431 | gray = (gray & 0x03) * 0x55;
|
---|
| 4432 | sp = row + (size_t)((row_width - 1) >> 2);
|
---|
| 4433 | dp = row + (size_t)row_width - 1;
|
---|
| 4434 | shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
|
---|
| 4435 | for (i = 0; i < row_width; i++)
|
---|
| 4436 | {
|
---|
| 4437 | value = (*sp >> shift) & 0x03;
|
---|
| 4438 | *dp = (png_byte)(value | (value << 2) | (value << 4) |
|
---|
| 4439 | (value << 6));
|
---|
| 4440 | if (shift == 6)
|
---|
| 4441 | {
|
---|
| 4442 | shift = 0;
|
---|
| 4443 | sp--;
|
---|
| 4444 | }
|
---|
| 4445 |
|
---|
| 4446 | else
|
---|
| 4447 | shift += 2;
|
---|
| 4448 |
|
---|
| 4449 | dp--;
|
---|
| 4450 | }
|
---|
| 4451 | break;
|
---|
| 4452 | }
|
---|
| 4453 |
|
---|
| 4454 | case 4:
|
---|
| 4455 | {
|
---|
| 4456 | gray = (gray & 0x0f) * 0x11;
|
---|
| 4457 | sp = row + (size_t)((row_width - 1) >> 1);
|
---|
| 4458 | dp = row + (size_t)row_width - 1;
|
---|
| 4459 | shift = (int)((1 - ((row_width + 1) & 0x01)) << 2);
|
---|
| 4460 | for (i = 0; i < row_width; i++)
|
---|
| 4461 | {
|
---|
| 4462 | value = (*sp >> shift) & 0x0f;
|
---|
| 4463 | *dp = (png_byte)(value | (value << 4));
|
---|
| 4464 | if (shift == 4)
|
---|
| 4465 | {
|
---|
| 4466 | shift = 0;
|
---|
| 4467 | sp--;
|
---|
| 4468 | }
|
---|
| 4469 |
|
---|
| 4470 | else
|
---|
| 4471 | shift = 4;
|
---|
| 4472 |
|
---|
| 4473 | dp--;
|
---|
| 4474 | }
|
---|
| 4475 | break;
|
---|
| 4476 | }
|
---|
| 4477 |
|
---|
| 4478 | default:
|
---|
| 4479 | break;
|
---|
| 4480 | }
|
---|
| 4481 |
|
---|
| 4482 | row_info->bit_depth = 8;
|
---|
| 4483 | row_info->pixel_depth = 8;
|
---|
| 4484 | row_info->rowbytes = row_width;
|
---|
| 4485 | }
|
---|
| 4486 |
|
---|
| 4487 | if (trans_color != NULL)
|
---|
| 4488 | {
|
---|
| 4489 | if (row_info->bit_depth == 8)
|
---|
| 4490 | {
|
---|
| 4491 | gray = gray & 0xff;
|
---|
| 4492 | sp = row + (size_t)row_width - 1;
|
---|
| 4493 | dp = row + ((size_t)row_width << 1) - 1;
|
---|
| 4494 |
|
---|
| 4495 | for (i = 0; i < row_width; i++)
|
---|
| 4496 | {
|
---|
| 4497 | if ((*sp & 0xffU) == gray)
|
---|
| 4498 | *dp-- = 0;
|
---|
| 4499 |
|
---|
| 4500 | else
|
---|
| 4501 | *dp-- = 0xff;
|
---|
| 4502 |
|
---|
| 4503 | *dp-- = *sp--;
|
---|
| 4504 | }
|
---|
| 4505 | }
|
---|
| 4506 |
|
---|
| 4507 | else if (row_info->bit_depth == 16)
|
---|
| 4508 | {
|
---|
| 4509 | unsigned int gray_high = (gray >> 8) & 0xff;
|
---|
| 4510 | unsigned int gray_low = gray & 0xff;
|
---|
| 4511 | sp = row + row_info->rowbytes - 1;
|
---|
| 4512 | dp = row + (row_info->rowbytes << 1) - 1;
|
---|
| 4513 | for (i = 0; i < row_width; i++)
|
---|
| 4514 | {
|
---|
| 4515 | if ((*(sp - 1) & 0xffU) == gray_high &&
|
---|
| 4516 | (*(sp) & 0xffU) == gray_low)
|
---|
| 4517 | {
|
---|
| 4518 | *dp-- = 0;
|
---|
| 4519 | *dp-- = 0;
|
---|
| 4520 | }
|
---|
| 4521 |
|
---|
| 4522 | else
|
---|
| 4523 | {
|
---|
| 4524 | *dp-- = 0xff;
|
---|
| 4525 | *dp-- = 0xff;
|
---|
| 4526 | }
|
---|
| 4527 |
|
---|
| 4528 | *dp-- = *sp--;
|
---|
| 4529 | *dp-- = *sp--;
|
---|
| 4530 | }
|
---|
| 4531 | }
|
---|
| 4532 |
|
---|
| 4533 | row_info->color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
|
---|
| 4534 | row_info->channels = 2;
|
---|
| 4535 | row_info->pixel_depth = (png_byte)(row_info->bit_depth << 1);
|
---|
| 4536 | row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
|
---|
| 4537 | row_width);
|
---|
| 4538 | }
|
---|
| 4539 | }
|
---|
| 4540 | else if (row_info->color_type == PNG_COLOR_TYPE_RGB &&
|
---|
| 4541 | trans_color != NULL)
|
---|
| 4542 | {
|
---|
| 4543 | if (row_info->bit_depth == 8)
|
---|
| 4544 | {
|
---|
| 4545 | png_byte red = (png_byte)(trans_color->red & 0xff);
|
---|
| 4546 | png_byte green = (png_byte)(trans_color->green & 0xff);
|
---|
| 4547 | png_byte blue = (png_byte)(trans_color->blue & 0xff);
|
---|
| 4548 | sp = row + (size_t)row_info->rowbytes - 1;
|
---|
| 4549 | dp = row + ((size_t)row_width << 2) - 1;
|
---|
| 4550 | for (i = 0; i < row_width; i++)
|
---|
| 4551 | {
|
---|
| 4552 | if (*(sp - 2) == red && *(sp - 1) == green && *(sp) == blue)
|
---|
| 4553 | *dp-- = 0;
|
---|
| 4554 |
|
---|
| 4555 | else
|
---|
| 4556 | *dp-- = 0xff;
|
---|
| 4557 |
|
---|
| 4558 | *dp-- = *sp--;
|
---|
| 4559 | *dp-- = *sp--;
|
---|
| 4560 | *dp-- = *sp--;
|
---|
| 4561 | }
|
---|
| 4562 | }
|
---|
| 4563 | else if (row_info->bit_depth == 16)
|
---|
| 4564 | {
|
---|
| 4565 | png_byte red_high = (png_byte)((trans_color->red >> 8) & 0xff);
|
---|
| 4566 | png_byte green_high = (png_byte)((trans_color->green >> 8) & 0xff);
|
---|
| 4567 | png_byte blue_high = (png_byte)((trans_color->blue >> 8) & 0xff);
|
---|
| 4568 | png_byte red_low = (png_byte)(trans_color->red & 0xff);
|
---|
| 4569 | png_byte green_low = (png_byte)(trans_color->green & 0xff);
|
---|
| 4570 | png_byte blue_low = (png_byte)(trans_color->blue & 0xff);
|
---|
| 4571 | sp = row + row_info->rowbytes - 1;
|
---|
| 4572 | dp = row + ((size_t)row_width << 3) - 1;
|
---|
| 4573 | for (i = 0; i < row_width; i++)
|
---|
| 4574 | {
|
---|
| 4575 | if (*(sp - 5) == red_high &&
|
---|
| 4576 | *(sp - 4) == red_low &&
|
---|
| 4577 | *(sp - 3) == green_high &&
|
---|
| 4578 | *(sp - 2) == green_low &&
|
---|
| 4579 | *(sp - 1) == blue_high &&
|
---|
| 4580 | *(sp ) == blue_low)
|
---|
| 4581 | {
|
---|
| 4582 | *dp-- = 0;
|
---|
| 4583 | *dp-- = 0;
|
---|
| 4584 | }
|
---|
| 4585 |
|
---|
| 4586 | else
|
---|
| 4587 | {
|
---|
| 4588 | *dp-- = 0xff;
|
---|
| 4589 | *dp-- = 0xff;
|
---|
| 4590 | }
|
---|
| 4591 |
|
---|
| 4592 | *dp-- = *sp--;
|
---|
| 4593 | *dp-- = *sp--;
|
---|
| 4594 | *dp-- = *sp--;
|
---|
| 4595 | *dp-- = *sp--;
|
---|
| 4596 | *dp-- = *sp--;
|
---|
| 4597 | *dp-- = *sp--;
|
---|
| 4598 | }
|
---|
| 4599 | }
|
---|
| 4600 | row_info->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
|
---|
| 4601 | row_info->channels = 4;
|
---|
| 4602 | row_info->pixel_depth = (png_byte)(row_info->bit_depth << 2);
|
---|
| 4603 | row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
|
---|
| 4604 | }
|
---|
| 4605 | }
|
---|
| 4606 | #endif
|
---|
| 4607 |
|
---|
| 4608 | #ifdef PNG_READ_EXPAND_16_SUPPORTED
|
---|
| 4609 | /* If the bit depth is 8 and the color type is not a palette type expand the
|
---|
| 4610 | * whole row to 16 bits. Has no effect otherwise.
|
---|
| 4611 | */
|
---|
| 4612 | static void
|
---|
| 4613 | png_do_expand_16(png_row_infop row_info, png_bytep row)
|
---|
| 4614 | {
|
---|
| 4615 | if (row_info->bit_depth == 8 &&
|
---|
| 4616 | row_info->color_type != PNG_COLOR_TYPE_PALETTE)
|
---|
| 4617 | {
|
---|
| 4618 | /* The row have a sequence of bytes containing [0..255] and we need
|
---|
| 4619 | * to turn it into another row containing [0..65535], to do this we
|
---|
| 4620 | * calculate:
|
---|
| 4621 | *
|
---|
| 4622 | * (input / 255) * 65535
|
---|
| 4623 | *
|
---|
| 4624 | * Which happens to be exactly input * 257 and this can be achieved
|
---|
| 4625 | * simply by byte replication in place (copying backwards).
|
---|
| 4626 | */
|
---|
| 4627 | png_byte *sp = row + row_info->rowbytes; /* source, last byte + 1 */
|
---|
| 4628 | png_byte *dp = sp + row_info->rowbytes; /* destination, end + 1 */
|
---|
| 4629 | while (dp > sp)
|
---|
| 4630 | {
|
---|
| 4631 | dp[-2] = dp[-1] = *--sp; dp -= 2;
|
---|
| 4632 | }
|
---|
| 4633 |
|
---|
| 4634 | row_info->rowbytes *= 2;
|
---|
| 4635 | row_info->bit_depth = 16;
|
---|
| 4636 | row_info->pixel_depth = (png_byte)(row_info->channels * 16);
|
---|
| 4637 | }
|
---|
| 4638 | }
|
---|
| 4639 | #endif
|
---|
| 4640 |
|
---|
| 4641 | #ifdef PNG_READ_QUANTIZE_SUPPORTED
|
---|
| 4642 | static void
|
---|
| 4643 | png_do_quantize(png_row_infop row_info, png_bytep row,
|
---|
| 4644 | png_const_bytep palette_lookup, png_const_bytep quantize_lookup)
|
---|
| 4645 | {
|
---|
| 4646 | png_bytep sp, dp;
|
---|
| 4647 | png_uint_32 i;
|
---|
| 4648 | png_uint_32 row_width=row_info->width;
|
---|
| 4649 |
|
---|
| 4650 | png_debug(1, "in png_do_quantize");
|
---|
| 4651 |
|
---|
| 4652 | if (row_info->bit_depth == 8)
|
---|
| 4653 | {
|
---|
| 4654 | if (row_info->color_type == PNG_COLOR_TYPE_RGB && palette_lookup)
|
---|
| 4655 | {
|
---|
| 4656 | int r, g, b, p;
|
---|
| 4657 | sp = row;
|
---|
| 4658 | dp = row;
|
---|
| 4659 | for (i = 0; i < row_width; i++)
|
---|
| 4660 | {
|
---|
| 4661 | r = *sp++;
|
---|
| 4662 | g = *sp++;
|
---|
| 4663 | b = *sp++;
|
---|
| 4664 |
|
---|
| 4665 | /* This looks real messy, but the compiler will reduce
|
---|
| 4666 | * it down to a reasonable formula. For example, with
|
---|
| 4667 | * 5 bits per color, we get:
|
---|
| 4668 | * p = (((r >> 3) & 0x1f) << 10) |
|
---|
| 4669 | * (((g >> 3) & 0x1f) << 5) |
|
---|
| 4670 | * ((b >> 3) & 0x1f);
|
---|
| 4671 | */
|
---|
| 4672 | p = (((r >> (8 - PNG_QUANTIZE_RED_BITS)) &
|
---|
| 4673 | ((1 << PNG_QUANTIZE_RED_BITS) - 1)) <<
|
---|
| 4674 | (PNG_QUANTIZE_GREEN_BITS + PNG_QUANTIZE_BLUE_BITS)) |
|
---|
| 4675 | (((g >> (8 - PNG_QUANTIZE_GREEN_BITS)) &
|
---|
| 4676 | ((1 << PNG_QUANTIZE_GREEN_BITS) - 1)) <<
|
---|
| 4677 | (PNG_QUANTIZE_BLUE_BITS)) |
|
---|
| 4678 | ((b >> (8 - PNG_QUANTIZE_BLUE_BITS)) &
|
---|
| 4679 | ((1 << PNG_QUANTIZE_BLUE_BITS) - 1));
|
---|
| 4680 |
|
---|
| 4681 | *dp++ = palette_lookup[p];
|
---|
| 4682 | }
|
---|
| 4683 |
|
---|
| 4684 | row_info->color_type = PNG_COLOR_TYPE_PALETTE;
|
---|
| 4685 | row_info->channels = 1;
|
---|
| 4686 | row_info->pixel_depth = row_info->bit_depth;
|
---|
| 4687 | row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
|
---|
| 4688 | }
|
---|
| 4689 |
|
---|
| 4690 | else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
|
---|
| 4691 | palette_lookup != NULL)
|
---|
| 4692 | {
|
---|
| 4693 | int r, g, b, p;
|
---|
| 4694 | sp = row;
|
---|
| 4695 | dp = row;
|
---|
| 4696 | for (i = 0; i < row_width; i++)
|
---|
| 4697 | {
|
---|
| 4698 | r = *sp++;
|
---|
| 4699 | g = *sp++;
|
---|
| 4700 | b = *sp++;
|
---|
| 4701 | sp++;
|
---|
| 4702 |
|
---|
| 4703 | p = (((r >> (8 - PNG_QUANTIZE_RED_BITS)) &
|
---|
| 4704 | ((1 << PNG_QUANTIZE_RED_BITS) - 1)) <<
|
---|
| 4705 | (PNG_QUANTIZE_GREEN_BITS + PNG_QUANTIZE_BLUE_BITS)) |
|
---|
| 4706 | (((g >> (8 - PNG_QUANTIZE_GREEN_BITS)) &
|
---|
| 4707 | ((1 << PNG_QUANTIZE_GREEN_BITS) - 1)) <<
|
---|
| 4708 | (PNG_QUANTIZE_BLUE_BITS)) |
|
---|
| 4709 | ((b >> (8 - PNG_QUANTIZE_BLUE_BITS)) &
|
---|
| 4710 | ((1 << PNG_QUANTIZE_BLUE_BITS) - 1));
|
---|
| 4711 |
|
---|
| 4712 | *dp++ = palette_lookup[p];
|
---|
| 4713 | }
|
---|
| 4714 |
|
---|
| 4715 | row_info->color_type = PNG_COLOR_TYPE_PALETTE;
|
---|
| 4716 | row_info->channels = 1;
|
---|
| 4717 | row_info->pixel_depth = row_info->bit_depth;
|
---|
| 4718 | row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_width);
|
---|
| 4719 | }
|
---|
| 4720 |
|
---|
| 4721 | else if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
|
---|
| 4722 | quantize_lookup)
|
---|
| 4723 | {
|
---|
| 4724 | sp = row;
|
---|
| 4725 |
|
---|
| 4726 | for (i = 0; i < row_width; i++, sp++)
|
---|
| 4727 | {
|
---|
| 4728 | *sp = quantize_lookup[*sp];
|
---|
| 4729 | }
|
---|
| 4730 | }
|
---|
| 4731 | }
|
---|
| 4732 | }
|
---|
| 4733 | #endif /* READ_QUANTIZE */
|
---|
| 4734 |
|
---|
| 4735 | /* Transform the row. The order of transformations is significant,
|
---|
| 4736 | * and is very touchy. If you add a transformation, take care to
|
---|
| 4737 | * decide how it fits in with the other transformations here.
|
---|
| 4738 | */
|
---|
| 4739 | void /* PRIVATE */
|
---|
| 4740 | png_do_read_transformations(png_structrp png_ptr, png_row_infop row_info)
|
---|
| 4741 | {
|
---|
| 4742 | png_debug(1, "in png_do_read_transformations");
|
---|
| 4743 |
|
---|
| 4744 | if (png_ptr->row_buf == NULL)
|
---|
| 4745 | {
|
---|
| 4746 | /* Prior to 1.5.4 this output row/pass where the NULL pointer is, but this
|
---|
| 4747 | * error is incredibly rare and incredibly easy to debug without this
|
---|
| 4748 | * information.
|
---|
| 4749 | */
|
---|
| 4750 | png_error(png_ptr, "NULL row buffer");
|
---|
| 4751 | }
|
---|
| 4752 |
|
---|
| 4753 | /* The following is debugging; prior to 1.5.4 the code was never compiled in;
|
---|
| 4754 | * in 1.5.4 PNG_FLAG_DETECT_UNINITIALIZED was added and the macro
|
---|
| 4755 | * PNG_WARN_UNINITIALIZED_ROW removed. In 1.6 the new flag is set only for
|
---|
| 4756 | * all transformations, however in practice the ROW_INIT always gets done on
|
---|
| 4757 | * demand, if necessary.
|
---|
| 4758 | */
|
---|
| 4759 | if ((png_ptr->flags & PNG_FLAG_DETECT_UNINITIALIZED) != 0 &&
|
---|
| 4760 | (png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
|
---|
| 4761 | {
|
---|
| 4762 | /* Application has failed to call either png_read_start_image() or
|
---|
| 4763 | * png_read_update_info() after setting transforms that expand pixels.
|
---|
| 4764 | * This check added to libpng-1.2.19 (but not enabled until 1.5.4).
|
---|
| 4765 | */
|
---|
| 4766 | png_error(png_ptr, "Uninitialized row");
|
---|
| 4767 | }
|
---|
| 4768 |
|
---|
| 4769 | #ifdef PNG_READ_EXPAND_SUPPORTED
|
---|
| 4770 | if ((png_ptr->transformations & PNG_EXPAND) != 0)
|
---|
| 4771 | {
|
---|
| 4772 | if (row_info->color_type == PNG_COLOR_TYPE_PALETTE)
|
---|
| 4773 | {
|
---|
| 4774 | #ifdef PNG_ARM_NEON_INTRINSICS_AVAILABLE
|
---|
| 4775 | if ((png_ptr->num_trans > 0) && (png_ptr->bit_depth == 8))
|
---|
| 4776 | {
|
---|
| 4777 | if (png_ptr->riffled_palette == NULL)
|
---|
| 4778 | {
|
---|
| 4779 | /* Initialize the accelerated palette expansion. */
|
---|
| 4780 | png_ptr->riffled_palette =
|
---|
| 4781 | (png_bytep)png_malloc(png_ptr, 256 * 4);
|
---|
| 4782 | png_riffle_palette_neon(png_ptr);
|
---|
| 4783 | }
|
---|
| 4784 | }
|
---|
| 4785 | #endif
|
---|
| 4786 | png_do_expand_palette(png_ptr, row_info, png_ptr->row_buf + 1,
|
---|
| 4787 | png_ptr->palette, png_ptr->trans_alpha, png_ptr->num_trans);
|
---|
| 4788 | }
|
---|
| 4789 |
|
---|
| 4790 | else
|
---|
| 4791 | {
|
---|
| 4792 | if (png_ptr->num_trans != 0 &&
|
---|
| 4793 | (png_ptr->transformations & PNG_EXPAND_tRNS) != 0)
|
---|
| 4794 | png_do_expand(row_info, png_ptr->row_buf + 1,
|
---|
| 4795 | &(png_ptr->trans_color));
|
---|
| 4796 |
|
---|
| 4797 | else
|
---|
| 4798 | png_do_expand(row_info, png_ptr->row_buf + 1, NULL);
|
---|
| 4799 | }
|
---|
| 4800 | }
|
---|
| 4801 | #endif
|
---|
| 4802 |
|
---|
| 4803 | #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
|
---|
| 4804 | if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0 &&
|
---|
| 4805 | (png_ptr->transformations & PNG_COMPOSE) == 0 &&
|
---|
| 4806 | (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
|
---|
| 4807 | row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
|
---|
| 4808 | png_do_strip_channel(row_info, png_ptr->row_buf + 1,
|
---|
| 4809 | 0 /* at_start == false, because SWAP_ALPHA happens later */);
|
---|
| 4810 | #endif
|
---|
| 4811 |
|
---|
| 4812 | #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
|
---|
| 4813 | if ((png_ptr->transformations & PNG_RGB_TO_GRAY) != 0)
|
---|
| 4814 | {
|
---|
| 4815 | int rgb_error =
|
---|
| 4816 | png_do_rgb_to_gray(png_ptr, row_info,
|
---|
| 4817 | png_ptr->row_buf + 1);
|
---|
| 4818 |
|
---|
| 4819 | if (rgb_error != 0)
|
---|
| 4820 | {
|
---|
| 4821 | png_ptr->rgb_to_gray_status=1;
|
---|
| 4822 | if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
|
---|
| 4823 | PNG_RGB_TO_GRAY_WARN)
|
---|
| 4824 | png_warning(png_ptr, "png_do_rgb_to_gray found nongray pixel");
|
---|
| 4825 |
|
---|
| 4826 | if ((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
|
---|
| 4827 | PNG_RGB_TO_GRAY_ERR)
|
---|
| 4828 | png_error(png_ptr, "png_do_rgb_to_gray found nongray pixel");
|
---|
| 4829 | }
|
---|
| 4830 | }
|
---|
| 4831 | #endif
|
---|
| 4832 |
|
---|
| 4833 | /* From Andreas Dilger e-mail to png-implement, 26 March 1998:
|
---|
| 4834 | *
|
---|
| 4835 | * In most cases, the "simple transparency" should be done prior to doing
|
---|
| 4836 | * gray-to-RGB, or you will have to test 3x as many bytes to check if a
|
---|
| 4837 | * pixel is transparent. You would also need to make sure that the
|
---|
| 4838 | * transparency information is upgraded to RGB.
|
---|
| 4839 | *
|
---|
| 4840 | * To summarize, the current flow is:
|
---|
| 4841 | * - Gray + simple transparency -> compare 1 or 2 gray bytes and composite
|
---|
| 4842 | * with background "in place" if transparent,
|
---|
| 4843 | * convert to RGB if necessary
|
---|
| 4844 | * - Gray + alpha -> composite with gray background and remove alpha bytes,
|
---|
| 4845 | * convert to RGB if necessary
|
---|
| 4846 | *
|
---|
| 4847 | * To support RGB backgrounds for gray images we need:
|
---|
| 4848 | * - Gray + simple transparency -> convert to RGB + simple transparency,
|
---|
| 4849 | * compare 3 or 6 bytes and composite with
|
---|
| 4850 | * background "in place" if transparent
|
---|
| 4851 | * (3x compare/pixel compared to doing
|
---|
| 4852 | * composite with gray bkgrnd)
|
---|
| 4853 | * - Gray + alpha -> convert to RGB + alpha, composite with background and
|
---|
| 4854 | * remove alpha bytes (3x float
|
---|
| 4855 | * operations/pixel compared with composite
|
---|
| 4856 | * on gray background)
|
---|
| 4857 | *
|
---|
| 4858 | * Greg's change will do this. The reason it wasn't done before is for
|
---|
| 4859 | * performance, as this increases the per-pixel operations. If we would check
|
---|
| 4860 | * in advance if the background was gray or RGB, and position the gray-to-RGB
|
---|
| 4861 | * transform appropriately, then it would save a lot of work/time.
|
---|
| 4862 | */
|
---|
| 4863 |
|
---|
| 4864 | #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
|
---|
| 4865 | /* If gray -> RGB, do so now only if background is non-gray; else do later
|
---|
| 4866 | * for performance reasons
|
---|
| 4867 | */
|
---|
| 4868 | if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0 &&
|
---|
| 4869 | (png_ptr->mode & PNG_BACKGROUND_IS_GRAY) == 0)
|
---|
| 4870 | png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
|
---|
| 4871 | #endif
|
---|
| 4872 |
|
---|
| 4873 | #if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
|
---|
| 4874 | defined(PNG_READ_ALPHA_MODE_SUPPORTED)
|
---|
| 4875 | if ((png_ptr->transformations & PNG_COMPOSE) != 0)
|
---|
| 4876 | png_do_compose(row_info, png_ptr->row_buf + 1, png_ptr);
|
---|
| 4877 | #endif
|
---|
| 4878 |
|
---|
| 4879 | #ifdef PNG_READ_GAMMA_SUPPORTED
|
---|
| 4880 | if ((png_ptr->transformations & PNG_GAMMA) != 0 &&
|
---|
| 4881 | #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
|
---|
| 4882 | /* Because RGB_TO_GRAY does the gamma transform. */
|
---|
| 4883 | (png_ptr->transformations & PNG_RGB_TO_GRAY) == 0 &&
|
---|
| 4884 | #endif
|
---|
| 4885 | #if defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
|
---|
| 4886 | defined(PNG_READ_ALPHA_MODE_SUPPORTED)
|
---|
| 4887 | /* Because PNG_COMPOSE does the gamma transform if there is something to
|
---|
| 4888 | * do (if there is an alpha channel or transparency.)
|
---|
| 4889 | */
|
---|
| 4890 | !((png_ptr->transformations & PNG_COMPOSE) != 0 &&
|
---|
| 4891 | ((png_ptr->num_trans != 0) ||
|
---|
| 4892 | (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)) &&
|
---|
| 4893 | #endif
|
---|
| 4894 | /* Because png_init_read_transformations transforms the palette, unless
|
---|
| 4895 | * RGB_TO_GRAY will do the transform.
|
---|
| 4896 | */
|
---|
| 4897 | (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE))
|
---|
| 4898 | png_do_gamma(row_info, png_ptr->row_buf + 1, png_ptr);
|
---|
| 4899 | #endif
|
---|
| 4900 |
|
---|
| 4901 | #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
|
---|
| 4902 | if ((png_ptr->transformations & PNG_STRIP_ALPHA) != 0 &&
|
---|
| 4903 | (png_ptr->transformations & PNG_COMPOSE) != 0 &&
|
---|
| 4904 | (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
|
---|
| 4905 | row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA))
|
---|
| 4906 | png_do_strip_channel(row_info, png_ptr->row_buf + 1,
|
---|
| 4907 | 0 /* at_start == false, because SWAP_ALPHA happens later */);
|
---|
| 4908 | #endif
|
---|
| 4909 |
|
---|
| 4910 | #ifdef PNG_READ_ALPHA_MODE_SUPPORTED
|
---|
| 4911 | if ((png_ptr->transformations & PNG_ENCODE_ALPHA) != 0 &&
|
---|
| 4912 | (row_info->color_type & PNG_COLOR_MASK_ALPHA) != 0)
|
---|
| 4913 | png_do_encode_alpha(row_info, png_ptr->row_buf + 1, png_ptr);
|
---|
| 4914 | #endif
|
---|
| 4915 |
|
---|
| 4916 | #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
|
---|
| 4917 | if ((png_ptr->transformations & PNG_SCALE_16_TO_8) != 0)
|
---|
| 4918 | png_do_scale_16_to_8(row_info, png_ptr->row_buf + 1);
|
---|
| 4919 | #endif
|
---|
| 4920 |
|
---|
| 4921 | #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
|
---|
| 4922 | /* There is no harm in doing both of these because only one has any effect,
|
---|
| 4923 | * by putting the 'scale' option first if the app asks for scale (either by
|
---|
| 4924 | * calling the API or in a TRANSFORM flag) this is what happens.
|
---|
| 4925 | */
|
---|
| 4926 | if ((png_ptr->transformations & PNG_16_TO_8) != 0)
|
---|
| 4927 | png_do_chop(row_info, png_ptr->row_buf + 1);
|
---|
| 4928 | #endif
|
---|
| 4929 |
|
---|
| 4930 | #ifdef PNG_READ_QUANTIZE_SUPPORTED
|
---|
| 4931 | if ((png_ptr->transformations & PNG_QUANTIZE) != 0)
|
---|
| 4932 | {
|
---|
| 4933 | png_do_quantize(row_info, png_ptr->row_buf + 1,
|
---|
| 4934 | png_ptr->palette_lookup, png_ptr->quantize_index);
|
---|
| 4935 |
|
---|
| 4936 | if (row_info->rowbytes == 0)
|
---|
| 4937 | png_error(png_ptr, "png_do_quantize returned rowbytes=0");
|
---|
| 4938 | }
|
---|
| 4939 | #endif /* READ_QUANTIZE */
|
---|
| 4940 |
|
---|
| 4941 | #ifdef PNG_READ_EXPAND_16_SUPPORTED
|
---|
| 4942 | /* Do the expansion now, after all the arithmetic has been done. Notice
|
---|
| 4943 | * that previous transformations can handle the PNG_EXPAND_16 flag if this
|
---|
| 4944 | * is efficient (particularly true in the case of gamma correction, where
|
---|
| 4945 | * better accuracy results faster!)
|
---|
| 4946 | */
|
---|
| 4947 | if ((png_ptr->transformations & PNG_EXPAND_16) != 0)
|
---|
| 4948 | png_do_expand_16(row_info, png_ptr->row_buf + 1);
|
---|
| 4949 | #endif
|
---|
| 4950 |
|
---|
| 4951 | #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
|
---|
| 4952 | /* NOTE: moved here in 1.5.4 (from much later in this list.) */
|
---|
| 4953 | if ((png_ptr->transformations & PNG_GRAY_TO_RGB) != 0 &&
|
---|
| 4954 | (png_ptr->mode & PNG_BACKGROUND_IS_GRAY) != 0)
|
---|
| 4955 | png_do_gray_to_rgb(row_info, png_ptr->row_buf + 1);
|
---|
| 4956 | #endif
|
---|
| 4957 |
|
---|
| 4958 | #ifdef PNG_READ_INVERT_SUPPORTED
|
---|
| 4959 | if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
|
---|
| 4960 | png_do_invert(row_info, png_ptr->row_buf + 1);
|
---|
| 4961 | #endif
|
---|
| 4962 |
|
---|
| 4963 | #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
|
---|
| 4964 | if ((png_ptr->transformations & PNG_INVERT_ALPHA) != 0)
|
---|
| 4965 | png_do_read_invert_alpha(row_info, png_ptr->row_buf + 1);
|
---|
| 4966 | #endif
|
---|
| 4967 |
|
---|
| 4968 | #ifdef PNG_READ_SHIFT_SUPPORTED
|
---|
| 4969 | if ((png_ptr->transformations & PNG_SHIFT) != 0)
|
---|
| 4970 | png_do_unshift(row_info, png_ptr->row_buf + 1,
|
---|
| 4971 | &(png_ptr->shift));
|
---|
| 4972 | #endif
|
---|
| 4973 |
|
---|
| 4974 | #ifdef PNG_READ_PACK_SUPPORTED
|
---|
| 4975 | if ((png_ptr->transformations & PNG_PACK) != 0)
|
---|
| 4976 | png_do_unpack(row_info, png_ptr->row_buf + 1);
|
---|
| 4977 | #endif
|
---|
| 4978 |
|
---|
| 4979 | #ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
|
---|
| 4980 | /* Added at libpng-1.5.10 */
|
---|
| 4981 | if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
|
---|
| 4982 | png_ptr->num_palette_max >= 0)
|
---|
| 4983 | png_do_check_palette_indexes(png_ptr, row_info);
|
---|
| 4984 | #endif
|
---|
| 4985 |
|
---|
| 4986 | #ifdef PNG_READ_BGR_SUPPORTED
|
---|
| 4987 | if ((png_ptr->transformations & PNG_BGR) != 0)
|
---|
| 4988 | png_do_bgr(row_info, png_ptr->row_buf + 1);
|
---|
| 4989 | #endif
|
---|
| 4990 |
|
---|
| 4991 | #ifdef PNG_READ_PACKSWAP_SUPPORTED
|
---|
| 4992 | if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
|
---|
| 4993 | png_do_packswap(row_info, png_ptr->row_buf + 1);
|
---|
| 4994 | #endif
|
---|
| 4995 |
|
---|
| 4996 | #ifdef PNG_READ_FILLER_SUPPORTED
|
---|
| 4997 | if ((png_ptr->transformations & PNG_FILLER) != 0)
|
---|
| 4998 | png_do_read_filler(row_info, png_ptr->row_buf + 1,
|
---|
| 4999 | (png_uint_32)png_ptr->filler, png_ptr->flags);
|
---|
| 5000 | #endif
|
---|
| 5001 |
|
---|
| 5002 | #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
|
---|
| 5003 | if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0)
|
---|
| 5004 | png_do_read_swap_alpha(row_info, png_ptr->row_buf + 1);
|
---|
| 5005 | #endif
|
---|
| 5006 |
|
---|
| 5007 | #ifdef PNG_READ_16BIT_SUPPORTED
|
---|
| 5008 | #ifdef PNG_READ_SWAP_SUPPORTED
|
---|
| 5009 | if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
|
---|
| 5010 | png_do_swap(row_info, png_ptr->row_buf + 1);
|
---|
| 5011 | #endif
|
---|
| 5012 | #endif
|
---|
| 5013 |
|
---|
| 5014 | #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
|
---|
| 5015 | if ((png_ptr->transformations & PNG_USER_TRANSFORM) != 0)
|
---|
| 5016 | {
|
---|
| 5017 | if (png_ptr->read_user_transform_fn != NULL)
|
---|
| 5018 | (*(png_ptr->read_user_transform_fn)) /* User read transform function */
|
---|
| 5019 | (png_ptr, /* png_ptr */
|
---|
| 5020 | row_info, /* row_info: */
|
---|
| 5021 | /* png_uint_32 width; width of row */
|
---|
| 5022 | /* size_t rowbytes; number of bytes in row */
|
---|
| 5023 | /* png_byte color_type; color type of pixels */
|
---|
| 5024 | /* png_byte bit_depth; bit depth of samples */
|
---|
| 5025 | /* png_byte channels; number of channels (1-4) */
|
---|
| 5026 | /* png_byte pixel_depth; bits per pixel (depth*channels) */
|
---|
| 5027 | png_ptr->row_buf + 1); /* start of pixel data for row */
|
---|
| 5028 | #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
|
---|
| 5029 | if (png_ptr->user_transform_depth != 0)
|
---|
| 5030 | row_info->bit_depth = png_ptr->user_transform_depth;
|
---|
| 5031 |
|
---|
| 5032 | if (png_ptr->user_transform_channels != 0)
|
---|
| 5033 | row_info->channels = png_ptr->user_transform_channels;
|
---|
| 5034 | #endif
|
---|
| 5035 | row_info->pixel_depth = (png_byte)(row_info->bit_depth *
|
---|
| 5036 | row_info->channels);
|
---|
| 5037 |
|
---|
| 5038 | row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth, row_info->width);
|
---|
| 5039 | }
|
---|
| 5040 | #endif
|
---|
| 5041 | }
|
---|
| 5042 |
|
---|
| 5043 | #endif /* READ_TRANSFORMS */
|
---|
| 5044 | #endif /* READ */
|
---|