[96425] | 1 |
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| 2 | /* pngread.c - read a PNG file
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| 3 | *
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| 4 | * Copyright (c) 2018-2019 Cosmin Truta
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| 5 | * Copyright (c) 1998-2002,2004,2006-2018 Glenn Randers-Pehrson
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| 6 | * Copyright (c) 1996-1997 Andreas Dilger
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| 7 | * Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.
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| 8 | *
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| 9 | * This code is released under the libpng license.
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| 10 | * For conditions of distribution and use, see the disclaimer
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| 11 | * and license in png.h
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| 12 | *
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| 13 | * This file contains routines that an application calls directly to
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| 14 | * read a PNG file or stream.
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| 15 | */
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| 16 |
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| 17 | #include "pngpriv.h"
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| 18 | #if defined(PNG_SIMPLIFIED_READ_SUPPORTED) && defined(PNG_STDIO_SUPPORTED)
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| 19 | # include <errno.h>
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| 20 | #endif
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| 21 |
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| 22 | #ifdef PNG_READ_SUPPORTED
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| 23 |
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| 24 | /* Create a PNG structure for reading, and allocate any memory needed. */
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| 25 | PNG_FUNCTION(png_structp,PNGAPI
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| 26 | png_create_read_struct,(png_const_charp user_png_ver, png_voidp error_ptr,
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| 27 | png_error_ptr error_fn, png_error_ptr warn_fn),PNG_ALLOCATED)
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| 28 | {
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| 29 | #ifndef PNG_USER_MEM_SUPPORTED
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| 30 | png_structp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
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| 31 | error_fn, warn_fn, NULL, NULL, NULL);
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| 32 | #else
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| 33 | return png_create_read_struct_2(user_png_ver, error_ptr, error_fn,
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| 34 | warn_fn, NULL, NULL, NULL);
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| 35 | }
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| 36 |
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| 37 | /* Alternate create PNG structure for reading, and allocate any memory
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| 38 | * needed.
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| 39 | */
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| 40 | PNG_FUNCTION(png_structp,PNGAPI
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| 41 | png_create_read_struct_2,(png_const_charp user_png_ver, png_voidp error_ptr,
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| 42 | png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
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| 43 | png_malloc_ptr malloc_fn, png_free_ptr free_fn),PNG_ALLOCATED)
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| 44 | {
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| 45 | png_structp png_ptr = png_create_png_struct(user_png_ver, error_ptr,
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| 46 | error_fn, warn_fn, mem_ptr, malloc_fn, free_fn);
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| 47 | #endif /* USER_MEM */
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| 48 |
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| 49 | if (png_ptr != NULL)
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| 50 | {
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| 51 | png_ptr->mode = PNG_IS_READ_STRUCT;
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| 52 |
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| 53 | /* Added in libpng-1.6.0; this can be used to detect a read structure if
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| 54 | * required (it will be zero in a write structure.)
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| 55 | */
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| 56 | # ifdef PNG_SEQUENTIAL_READ_SUPPORTED
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| 57 | png_ptr->IDAT_read_size = PNG_IDAT_READ_SIZE;
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| 58 | # endif
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| 59 |
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| 60 | # ifdef PNG_BENIGN_READ_ERRORS_SUPPORTED
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| 61 | png_ptr->flags |= PNG_FLAG_BENIGN_ERRORS_WARN;
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| 62 |
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| 63 | /* In stable builds only warn if an application error can be completely
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| 64 | * handled.
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| 65 | */
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| 66 | # if PNG_RELEASE_BUILD
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| 67 | png_ptr->flags |= PNG_FLAG_APP_WARNINGS_WARN;
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| 68 | # endif
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| 69 | # endif
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| 70 |
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| 71 | /* TODO: delay this, it can be done in png_init_io (if the app doesn't
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| 72 | * do it itself) avoiding setting the default function if it is not
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| 73 | * required.
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| 74 | */
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| 75 | png_set_read_fn(png_ptr, NULL, NULL);
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| 76 | }
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| 77 |
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| 78 | return png_ptr;
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| 79 | }
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| 80 |
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| 81 |
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| 82 | #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
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| 83 | /* Read the information before the actual image data. This has been
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| 84 | * changed in v0.90 to allow reading a file that already has the magic
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| 85 | * bytes read from the stream. You can tell libpng how many bytes have
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| 86 | * been read from the beginning of the stream (up to the maximum of 8)
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| 87 | * via png_set_sig_bytes(), and we will only check the remaining bytes
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| 88 | * here. The application can then have access to the signature bytes we
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| 89 | * read if it is determined that this isn't a valid PNG file.
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| 90 | */
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| 91 | void PNGAPI
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| 92 | png_read_info(png_structrp png_ptr, png_inforp info_ptr)
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| 93 | {
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| 94 | #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
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| 95 | int keep;
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| 96 | #endif
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| 97 |
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| 98 | png_debug(1, "in png_read_info");
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| 99 |
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| 100 | if (png_ptr == NULL || info_ptr == NULL)
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| 101 | return;
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| 102 |
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| 103 | /* Read and check the PNG file signature. */
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| 104 | png_read_sig(png_ptr, info_ptr);
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| 105 |
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| 106 | for (;;)
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| 107 | {
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| 108 | png_uint_32 length = png_read_chunk_header(png_ptr);
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| 109 | png_uint_32 chunk_name = png_ptr->chunk_name;
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| 110 |
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| 111 | /* IDAT logic needs to happen here to simplify getting the two flags
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| 112 | * right.
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| 113 | */
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| 114 | if (chunk_name == png_IDAT)
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| 115 | {
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| 116 | if ((png_ptr->mode & PNG_HAVE_IHDR) == 0)
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| 117 | png_chunk_error(png_ptr, "Missing IHDR before IDAT");
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| 118 |
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| 119 | else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
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| 120 | (png_ptr->mode & PNG_HAVE_PLTE) == 0)
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| 121 | png_chunk_error(png_ptr, "Missing PLTE before IDAT");
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| 122 |
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| 123 | else if ((png_ptr->mode & PNG_AFTER_IDAT) != 0)
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| 124 | png_chunk_benign_error(png_ptr, "Too many IDATs found");
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| 125 |
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| 126 | png_ptr->mode |= PNG_HAVE_IDAT;
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| 127 | }
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| 128 |
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| 129 | else if ((png_ptr->mode & PNG_HAVE_IDAT) != 0)
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| 130 | {
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| 131 | png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
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| 132 | png_ptr->mode |= PNG_AFTER_IDAT;
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| 133 | }
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| 134 |
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| 135 | /* This should be a binary subdivision search or a hash for
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| 136 | * matching the chunk name rather than a linear search.
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| 137 | */
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| 138 | if (chunk_name == png_IHDR)
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| 139 | png_handle_IHDR(png_ptr, info_ptr, length);
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| 140 |
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| 141 | else if (chunk_name == png_IEND)
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| 142 | png_handle_IEND(png_ptr, info_ptr, length);
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| 143 |
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| 144 | #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
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| 145 | else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
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| 146 | {
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| 147 | png_handle_unknown(png_ptr, info_ptr, length, keep);
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| 148 |
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| 149 | if (chunk_name == png_PLTE)
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| 150 | png_ptr->mode |= PNG_HAVE_PLTE;
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| 151 |
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| 152 | else if (chunk_name == png_IDAT)
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| 153 | {
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| 154 | png_ptr->idat_size = 0; /* It has been consumed */
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| 155 | break;
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| 156 | }
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| 157 | }
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| 158 | #endif
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| 159 | else if (chunk_name == png_PLTE)
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| 160 | png_handle_PLTE(png_ptr, info_ptr, length);
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| 161 |
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| 162 | else if (chunk_name == png_IDAT)
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| 163 | {
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| 164 | png_ptr->idat_size = length;
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| 165 | break;
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| 166 | }
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| 167 |
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| 168 | #ifdef PNG_READ_bKGD_SUPPORTED
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| 169 | else if (chunk_name == png_bKGD)
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| 170 | png_handle_bKGD(png_ptr, info_ptr, length);
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| 171 | #endif
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| 172 |
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| 173 | #ifdef PNG_READ_cHRM_SUPPORTED
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| 174 | else if (chunk_name == png_cHRM)
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| 175 | png_handle_cHRM(png_ptr, info_ptr, length);
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| 176 | #endif
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| 177 |
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| 178 | #ifdef PNG_READ_eXIf_SUPPORTED
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| 179 | else if (chunk_name == png_eXIf)
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| 180 | png_handle_eXIf(png_ptr, info_ptr, length);
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| 181 | #endif
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| 182 |
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| 183 | #ifdef PNG_READ_gAMA_SUPPORTED
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| 184 | else if (chunk_name == png_gAMA)
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| 185 | png_handle_gAMA(png_ptr, info_ptr, length);
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| 186 | #endif
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| 187 |
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| 188 | #ifdef PNG_READ_hIST_SUPPORTED
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| 189 | else if (chunk_name == png_hIST)
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| 190 | png_handle_hIST(png_ptr, info_ptr, length);
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| 191 | #endif
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| 192 |
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| 193 | #ifdef PNG_READ_oFFs_SUPPORTED
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| 194 | else if (chunk_name == png_oFFs)
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| 195 | png_handle_oFFs(png_ptr, info_ptr, length);
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| 196 | #endif
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| 197 |
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| 198 | #ifdef PNG_READ_pCAL_SUPPORTED
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| 199 | else if (chunk_name == png_pCAL)
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| 200 | png_handle_pCAL(png_ptr, info_ptr, length);
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| 201 | #endif
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| 202 |
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| 203 | #ifdef PNG_READ_sCAL_SUPPORTED
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| 204 | else if (chunk_name == png_sCAL)
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| 205 | png_handle_sCAL(png_ptr, info_ptr, length);
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| 206 | #endif
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| 207 |
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| 208 | #ifdef PNG_READ_pHYs_SUPPORTED
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| 209 | else if (chunk_name == png_pHYs)
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| 210 | png_handle_pHYs(png_ptr, info_ptr, length);
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| 211 | #endif
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| 212 |
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| 213 | #ifdef PNG_READ_sBIT_SUPPORTED
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| 214 | else if (chunk_name == png_sBIT)
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| 215 | png_handle_sBIT(png_ptr, info_ptr, length);
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| 216 | #endif
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| 217 |
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| 218 | #ifdef PNG_READ_sRGB_SUPPORTED
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| 219 | else if (chunk_name == png_sRGB)
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| 220 | png_handle_sRGB(png_ptr, info_ptr, length);
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| 221 | #endif
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| 222 |
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| 223 | #ifdef PNG_READ_iCCP_SUPPORTED
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| 224 | else if (chunk_name == png_iCCP)
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| 225 | png_handle_iCCP(png_ptr, info_ptr, length);
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| 226 | #endif
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| 227 |
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| 228 | #ifdef PNG_READ_sPLT_SUPPORTED
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| 229 | else if (chunk_name == png_sPLT)
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| 230 | png_handle_sPLT(png_ptr, info_ptr, length);
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| 231 | #endif
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| 232 |
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| 233 | #ifdef PNG_READ_tEXt_SUPPORTED
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| 234 | else if (chunk_name == png_tEXt)
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| 235 | png_handle_tEXt(png_ptr, info_ptr, length);
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| 236 | #endif
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| 237 |
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| 238 | #ifdef PNG_READ_tIME_SUPPORTED
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| 239 | else if (chunk_name == png_tIME)
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| 240 | png_handle_tIME(png_ptr, info_ptr, length);
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| 241 | #endif
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| 242 |
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| 243 | #ifdef PNG_READ_tRNS_SUPPORTED
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| 244 | else if (chunk_name == png_tRNS)
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| 245 | png_handle_tRNS(png_ptr, info_ptr, length);
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| 246 | #endif
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| 247 |
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| 248 | #ifdef PNG_READ_zTXt_SUPPORTED
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| 249 | else if (chunk_name == png_zTXt)
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| 250 | png_handle_zTXt(png_ptr, info_ptr, length);
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| 251 | #endif
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| 252 |
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| 253 | #ifdef PNG_READ_iTXt_SUPPORTED
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| 254 | else if (chunk_name == png_iTXt)
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| 255 | png_handle_iTXt(png_ptr, info_ptr, length);
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| 256 | #endif
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| 257 |
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| 258 | else
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| 259 | png_handle_unknown(png_ptr, info_ptr, length,
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| 260 | PNG_HANDLE_CHUNK_AS_DEFAULT);
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| 261 | }
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| 262 | }
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| 263 | #endif /* SEQUENTIAL_READ */
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| 264 |
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| 265 | /* Optional call to update the users info_ptr structure */
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| 266 | void PNGAPI
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| 267 | png_read_update_info(png_structrp png_ptr, png_inforp info_ptr)
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| 268 | {
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| 269 | png_debug(1, "in png_read_update_info");
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| 270 |
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| 271 | if (png_ptr != NULL)
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| 272 | {
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| 273 | if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
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| 274 | {
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| 275 | png_read_start_row(png_ptr);
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| 276 |
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| 277 | # ifdef PNG_READ_TRANSFORMS_SUPPORTED
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| 278 | png_read_transform_info(png_ptr, info_ptr);
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| 279 | # else
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| 280 | PNG_UNUSED(info_ptr)
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| 281 | # endif
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| 282 | }
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| 283 |
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| 284 | /* New in 1.6.0 this avoids the bug of doing the initializations twice */
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| 285 | else
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| 286 | png_app_error(png_ptr,
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| 287 | "png_read_update_info/png_start_read_image: duplicate call");
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| 288 | }
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| 289 | }
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| 290 |
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| 291 | #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
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| 292 | /* Initialize palette, background, etc, after transformations
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| 293 | * are set, but before any reading takes place. This allows
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| 294 | * the user to obtain a gamma-corrected palette, for example.
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| 295 | * If the user doesn't call this, we will do it ourselves.
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| 296 | */
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| 297 | void PNGAPI
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| 298 | png_start_read_image(png_structrp png_ptr)
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| 299 | {
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| 300 | png_debug(1, "in png_start_read_image");
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| 301 |
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| 302 | if (png_ptr != NULL)
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| 303 | {
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| 304 | if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
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| 305 | png_read_start_row(png_ptr);
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| 306 |
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| 307 | /* New in 1.6.0 this avoids the bug of doing the initializations twice */
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| 308 | else
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| 309 | png_app_error(png_ptr,
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| 310 | "png_start_read_image/png_read_update_info: duplicate call");
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| 311 | }
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| 312 | }
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| 313 | #endif /* SEQUENTIAL_READ */
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| 314 |
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| 315 | #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
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| 316 | #ifdef PNG_MNG_FEATURES_SUPPORTED
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| 317 | /* Undoes intrapixel differencing,
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| 318 | * NOTE: this is apparently only supported in the 'sequential' reader.
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| 319 | */
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| 320 | static void
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| 321 | png_do_read_intrapixel(png_row_infop row_info, png_bytep row)
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| 322 | {
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| 323 | png_debug(1, "in png_do_read_intrapixel");
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| 324 |
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| 325 | if (
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| 326 | (row_info->color_type & PNG_COLOR_MASK_COLOR) != 0)
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| 327 | {
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| 328 | int bytes_per_pixel;
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| 329 | png_uint_32 row_width = row_info->width;
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| 330 |
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| 331 | if (row_info->bit_depth == 8)
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| 332 | {
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| 333 | png_bytep rp;
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| 334 | png_uint_32 i;
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| 335 |
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| 336 | if (row_info->color_type == PNG_COLOR_TYPE_RGB)
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| 337 | bytes_per_pixel = 3;
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| 338 |
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| 339 | else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
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| 340 | bytes_per_pixel = 4;
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| 341 |
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| 342 | else
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| 343 | return;
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| 344 |
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| 345 | for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
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| 346 | {
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| 347 | *(rp) = (png_byte)((256 + *rp + *(rp + 1)) & 0xff);
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| 348 | *(rp+2) = (png_byte)((256 + *(rp + 2) + *(rp + 1)) & 0xff);
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| 349 | }
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| 350 | }
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| 351 | else if (row_info->bit_depth == 16)
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| 352 | {
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| 353 | png_bytep rp;
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| 354 | png_uint_32 i;
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| 355 |
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| 356 | if (row_info->color_type == PNG_COLOR_TYPE_RGB)
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| 357 | bytes_per_pixel = 6;
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| 358 |
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| 359 | else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
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| 360 | bytes_per_pixel = 8;
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| 361 |
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| 362 | else
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| 363 | return;
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| 364 |
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| 365 | for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
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| 366 | {
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| 367 | png_uint_32 s0 = (png_uint_32)(*(rp ) << 8) | *(rp + 1);
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| 368 | png_uint_32 s1 = (png_uint_32)(*(rp + 2) << 8) | *(rp + 3);
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| 369 | png_uint_32 s2 = (png_uint_32)(*(rp + 4) << 8) | *(rp + 5);
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| 370 | png_uint_32 red = (s0 + s1 + 65536) & 0xffff;
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| 371 | png_uint_32 blue = (s2 + s1 + 65536) & 0xffff;
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| 372 | *(rp ) = (png_byte)((red >> 8) & 0xff);
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| 373 | *(rp + 1) = (png_byte)(red & 0xff);
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| 374 | *(rp + 4) = (png_byte)((blue >> 8) & 0xff);
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| 375 | *(rp + 5) = (png_byte)(blue & 0xff);
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| 376 | }
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| 377 | }
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| 378 | }
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| 379 | }
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| 380 | #endif /* MNG_FEATURES */
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| 381 |
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| 382 | void PNGAPI
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| 383 | png_read_row(png_structrp png_ptr, png_bytep row, png_bytep dsp_row)
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| 384 | {
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| 385 | png_row_info row_info;
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| 386 |
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| 387 | if (png_ptr == NULL)
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| 388 | return;
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| 389 |
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| 390 | png_debug2(1, "in png_read_row (row %lu, pass %d)",
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| 391 | (unsigned long)png_ptr->row_number, png_ptr->pass);
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| 392 |
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| 393 | /* png_read_start_row sets the information (in particular iwidth) for this
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| 394 | * interlace pass.
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| 395 | */
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| 396 | if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
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| 397 | png_read_start_row(png_ptr);
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| 398 |
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| 399 | /* 1.5.6: row_info moved out of png_struct to a local here. */
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| 400 | row_info.width = png_ptr->iwidth; /* NOTE: width of current interlaced row */
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| 401 | row_info.color_type = png_ptr->color_type;
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| 402 | row_info.bit_depth = png_ptr->bit_depth;
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| 403 | row_info.channels = png_ptr->channels;
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| 404 | row_info.pixel_depth = png_ptr->pixel_depth;
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| 405 | row_info.rowbytes = PNG_ROWBYTES(row_info.pixel_depth, row_info.width);
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| 406 |
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| 407 | #ifdef PNG_WARNINGS_SUPPORTED
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| 408 | if (png_ptr->row_number == 0 && png_ptr->pass == 0)
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| 409 | {
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| 410 | /* Check for transforms that have been set but were defined out */
|
---|
| 411 | #if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED)
|
---|
| 412 | if ((png_ptr->transformations & PNG_INVERT_MONO) != 0)
|
---|
| 413 | png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined");
|
---|
| 414 | #endif
|
---|
| 415 |
|
---|
| 416 | #if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED)
|
---|
| 417 | if ((png_ptr->transformations & PNG_FILLER) != 0)
|
---|
| 418 | png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined");
|
---|
| 419 | #endif
|
---|
| 420 |
|
---|
| 421 | #if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && \
|
---|
| 422 | !defined(PNG_READ_PACKSWAP_SUPPORTED)
|
---|
| 423 | if ((png_ptr->transformations & PNG_PACKSWAP) != 0)
|
---|
| 424 | png_warning(png_ptr, "PNG_READ_PACKSWAP_SUPPORTED is not defined");
|
---|
| 425 | #endif
|
---|
| 426 |
|
---|
| 427 | #if defined(PNG_WRITE_PACK_SUPPORTED) && !defined(PNG_READ_PACK_SUPPORTED)
|
---|
| 428 | if ((png_ptr->transformations & PNG_PACK) != 0)
|
---|
| 429 | png_warning(png_ptr, "PNG_READ_PACK_SUPPORTED is not defined");
|
---|
| 430 | #endif
|
---|
| 431 |
|
---|
| 432 | #if defined(PNG_WRITE_SHIFT_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED)
|
---|
| 433 | if ((png_ptr->transformations & PNG_SHIFT) != 0)
|
---|
| 434 | png_warning(png_ptr, "PNG_READ_SHIFT_SUPPORTED is not defined");
|
---|
| 435 | #endif
|
---|
| 436 |
|
---|
| 437 | #if defined(PNG_WRITE_BGR_SUPPORTED) && !defined(PNG_READ_BGR_SUPPORTED)
|
---|
| 438 | if ((png_ptr->transformations & PNG_BGR) != 0)
|
---|
| 439 | png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined");
|
---|
| 440 | #endif
|
---|
| 441 |
|
---|
| 442 | #if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED)
|
---|
| 443 | if ((png_ptr->transformations & PNG_SWAP_BYTES) != 0)
|
---|
| 444 | png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined");
|
---|
| 445 | #endif
|
---|
| 446 | }
|
---|
| 447 | #endif /* WARNINGS */
|
---|
| 448 |
|
---|
| 449 | #ifdef PNG_READ_INTERLACING_SUPPORTED
|
---|
| 450 | /* If interlaced and we do not need a new row, combine row and return.
|
---|
| 451 | * Notice that the pixels we have from previous rows have been transformed
|
---|
| 452 | * already; we can only combine like with like (transformed or
|
---|
| 453 | * untransformed) and, because of the libpng API for interlaced images, this
|
---|
| 454 | * means we must transform before de-interlacing.
|
---|
| 455 | */
|
---|
| 456 | if (png_ptr->interlaced != 0 &&
|
---|
| 457 | (png_ptr->transformations & PNG_INTERLACE) != 0)
|
---|
| 458 | {
|
---|
| 459 | switch (png_ptr->pass)
|
---|
| 460 | {
|
---|
| 461 | case 0:
|
---|
| 462 | if (png_ptr->row_number & 0x07)
|
---|
| 463 | {
|
---|
| 464 | if (dsp_row != NULL)
|
---|
| 465 | png_combine_row(png_ptr, dsp_row, 1/*display*/);
|
---|
| 466 | png_read_finish_row(png_ptr);
|
---|
| 467 | return;
|
---|
| 468 | }
|
---|
| 469 | break;
|
---|
| 470 |
|
---|
| 471 | case 1:
|
---|
| 472 | if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
|
---|
| 473 | {
|
---|
| 474 | if (dsp_row != NULL)
|
---|
| 475 | png_combine_row(png_ptr, dsp_row, 1/*display*/);
|
---|
| 476 |
|
---|
| 477 | png_read_finish_row(png_ptr);
|
---|
| 478 | return;
|
---|
| 479 | }
|
---|
| 480 | break;
|
---|
| 481 |
|
---|
| 482 | case 2:
|
---|
| 483 | if ((png_ptr->row_number & 0x07) != 4)
|
---|
| 484 | {
|
---|
| 485 | if (dsp_row != NULL && (png_ptr->row_number & 4))
|
---|
| 486 | png_combine_row(png_ptr, dsp_row, 1/*display*/);
|
---|
| 487 |
|
---|
| 488 | png_read_finish_row(png_ptr);
|
---|
| 489 | return;
|
---|
| 490 | }
|
---|
| 491 | break;
|
---|
| 492 |
|
---|
| 493 | case 3:
|
---|
| 494 | if ((png_ptr->row_number & 3) || png_ptr->width < 3)
|
---|
| 495 | {
|
---|
| 496 | if (dsp_row != NULL)
|
---|
| 497 | png_combine_row(png_ptr, dsp_row, 1/*display*/);
|
---|
| 498 |
|
---|
| 499 | png_read_finish_row(png_ptr);
|
---|
| 500 | return;
|
---|
| 501 | }
|
---|
| 502 | break;
|
---|
| 503 |
|
---|
| 504 | case 4:
|
---|
| 505 | if ((png_ptr->row_number & 3) != 2)
|
---|
| 506 | {
|
---|
| 507 | if (dsp_row != NULL && (png_ptr->row_number & 2))
|
---|
| 508 | png_combine_row(png_ptr, dsp_row, 1/*display*/);
|
---|
| 509 |
|
---|
| 510 | png_read_finish_row(png_ptr);
|
---|
| 511 | return;
|
---|
| 512 | }
|
---|
| 513 | break;
|
---|
| 514 |
|
---|
| 515 | case 5:
|
---|
| 516 | if ((png_ptr->row_number & 1) || png_ptr->width < 2)
|
---|
| 517 | {
|
---|
| 518 | if (dsp_row != NULL)
|
---|
| 519 | png_combine_row(png_ptr, dsp_row, 1/*display*/);
|
---|
| 520 |
|
---|
| 521 | png_read_finish_row(png_ptr);
|
---|
| 522 | return;
|
---|
| 523 | }
|
---|
| 524 | break;
|
---|
| 525 |
|
---|
| 526 | default:
|
---|
| 527 | case 6:
|
---|
| 528 | if ((png_ptr->row_number & 1) == 0)
|
---|
| 529 | {
|
---|
| 530 | png_read_finish_row(png_ptr);
|
---|
| 531 | return;
|
---|
| 532 | }
|
---|
| 533 | break;
|
---|
| 534 | }
|
---|
| 535 | }
|
---|
| 536 | #endif
|
---|
| 537 |
|
---|
| 538 | if ((png_ptr->mode & PNG_HAVE_IDAT) == 0)
|
---|
| 539 | png_error(png_ptr, "Invalid attempt to read row data");
|
---|
| 540 |
|
---|
| 541 | /* Fill the row with IDAT data: */
|
---|
| 542 | png_ptr->row_buf[0]=255; /* to force error if no data was found */
|
---|
| 543 | png_read_IDAT_data(png_ptr, png_ptr->row_buf, row_info.rowbytes + 1);
|
---|
| 544 |
|
---|
| 545 | if (png_ptr->row_buf[0] > PNG_FILTER_VALUE_NONE)
|
---|
| 546 | {
|
---|
| 547 | if (png_ptr->row_buf[0] < PNG_FILTER_VALUE_LAST)
|
---|
| 548 | png_read_filter_row(png_ptr, &row_info, png_ptr->row_buf + 1,
|
---|
| 549 | png_ptr->prev_row + 1, png_ptr->row_buf[0]);
|
---|
| 550 | else
|
---|
| 551 | png_error(png_ptr, "bad adaptive filter value");
|
---|
| 552 | }
|
---|
| 553 |
|
---|
| 554 | /* libpng 1.5.6: the following line was copying png_ptr->rowbytes before
|
---|
| 555 | * 1.5.6, while the buffer really is this big in current versions of libpng
|
---|
| 556 | * it may not be in the future, so this was changed just to copy the
|
---|
| 557 | * interlaced count:
|
---|
| 558 | */
|
---|
| 559 | memcpy(png_ptr->prev_row, png_ptr->row_buf, row_info.rowbytes + 1);
|
---|
| 560 |
|
---|
| 561 | #ifdef PNG_MNG_FEATURES_SUPPORTED
|
---|
| 562 | if ((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) != 0 &&
|
---|
| 563 | (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
|
---|
| 564 | {
|
---|
| 565 | /* Intrapixel differencing */
|
---|
| 566 | png_do_read_intrapixel(&row_info, png_ptr->row_buf + 1);
|
---|
| 567 | }
|
---|
| 568 | #endif
|
---|
| 569 |
|
---|
| 570 | #ifdef PNG_READ_TRANSFORMS_SUPPORTED
|
---|
| 571 | if (png_ptr->transformations)
|
---|
| 572 | png_do_read_transformations(png_ptr, &row_info);
|
---|
| 573 | #endif
|
---|
| 574 |
|
---|
| 575 | /* The transformed pixel depth should match the depth now in row_info. */
|
---|
| 576 | if (png_ptr->transformed_pixel_depth == 0)
|
---|
| 577 | {
|
---|
| 578 | png_ptr->transformed_pixel_depth = row_info.pixel_depth;
|
---|
| 579 | if (row_info.pixel_depth > png_ptr->maximum_pixel_depth)
|
---|
| 580 | png_error(png_ptr, "sequential row overflow");
|
---|
| 581 | }
|
---|
| 582 |
|
---|
| 583 | else if (png_ptr->transformed_pixel_depth != row_info.pixel_depth)
|
---|
| 584 | png_error(png_ptr, "internal sequential row size calculation error");
|
---|
| 585 |
|
---|
| 586 | #ifdef PNG_READ_INTERLACING_SUPPORTED
|
---|
| 587 | /* Expand interlaced rows to full size */
|
---|
| 588 | if (png_ptr->interlaced != 0 &&
|
---|
| 589 | (png_ptr->transformations & PNG_INTERLACE) != 0)
|
---|
| 590 | {
|
---|
| 591 | if (png_ptr->pass < 6)
|
---|
| 592 | png_do_read_interlace(&row_info, png_ptr->row_buf + 1, png_ptr->pass,
|
---|
| 593 | png_ptr->transformations);
|
---|
| 594 |
|
---|
| 595 | if (dsp_row != NULL)
|
---|
| 596 | png_combine_row(png_ptr, dsp_row, 1/*display*/);
|
---|
| 597 |
|
---|
| 598 | if (row != NULL)
|
---|
| 599 | png_combine_row(png_ptr, row, 0/*row*/);
|
---|
| 600 | }
|
---|
| 601 |
|
---|
| 602 | else
|
---|
| 603 | #endif
|
---|
| 604 | {
|
---|
| 605 | if (row != NULL)
|
---|
| 606 | png_combine_row(png_ptr, row, -1/*ignored*/);
|
---|
| 607 |
|
---|
| 608 | if (dsp_row != NULL)
|
---|
| 609 | png_combine_row(png_ptr, dsp_row, -1/*ignored*/);
|
---|
| 610 | }
|
---|
| 611 | png_read_finish_row(png_ptr);
|
---|
| 612 |
|
---|
| 613 | if (png_ptr->read_row_fn != NULL)
|
---|
| 614 | (*(png_ptr->read_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
|
---|
| 615 |
|
---|
| 616 | }
|
---|
| 617 | #endif /* SEQUENTIAL_READ */
|
---|
| 618 |
|
---|
| 619 | #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
---|
| 620 | /* Read one or more rows of image data. If the image is interlaced,
|
---|
| 621 | * and png_set_interlace_handling() has been called, the rows need to
|
---|
| 622 | * contain the contents of the rows from the previous pass. If the
|
---|
| 623 | * image has alpha or transparency, and png_handle_alpha()[*] has been
|
---|
| 624 | * called, the rows contents must be initialized to the contents of the
|
---|
| 625 | * screen.
|
---|
| 626 | *
|
---|
| 627 | * "row" holds the actual image, and pixels are placed in it
|
---|
| 628 | * as they arrive. If the image is displayed after each pass, it will
|
---|
| 629 | * appear to "sparkle" in. "display_row" can be used to display a
|
---|
| 630 | * "chunky" progressive image, with finer detail added as it becomes
|
---|
| 631 | * available. If you do not want this "chunky" display, you may pass
|
---|
| 632 | * NULL for display_row. If you do not want the sparkle display, and
|
---|
| 633 | * you have not called png_handle_alpha(), you may pass NULL for rows.
|
---|
| 634 | * If you have called png_handle_alpha(), and the image has either an
|
---|
| 635 | * alpha channel or a transparency chunk, you must provide a buffer for
|
---|
| 636 | * rows. In this case, you do not have to provide a display_row buffer
|
---|
| 637 | * also, but you may. If the image is not interlaced, or if you have
|
---|
| 638 | * not called png_set_interlace_handling(), the display_row buffer will
|
---|
| 639 | * be ignored, so pass NULL to it.
|
---|
| 640 | *
|
---|
| 641 | * [*] png_handle_alpha() does not exist yet, as of this version of libpng
|
---|
| 642 | */
|
---|
| 643 |
|
---|
| 644 | void PNGAPI
|
---|
| 645 | png_read_rows(png_structrp png_ptr, png_bytepp row,
|
---|
| 646 | png_bytepp display_row, png_uint_32 num_rows)
|
---|
| 647 | {
|
---|
| 648 | png_uint_32 i;
|
---|
| 649 | png_bytepp rp;
|
---|
| 650 | png_bytepp dp;
|
---|
| 651 |
|
---|
| 652 | png_debug(1, "in png_read_rows");
|
---|
| 653 |
|
---|
| 654 | if (png_ptr == NULL)
|
---|
| 655 | return;
|
---|
| 656 |
|
---|
| 657 | rp = row;
|
---|
| 658 | dp = display_row;
|
---|
| 659 | if (rp != NULL && dp != NULL)
|
---|
| 660 | for (i = 0; i < num_rows; i++)
|
---|
| 661 | {
|
---|
| 662 | png_bytep rptr = *rp++;
|
---|
| 663 | png_bytep dptr = *dp++;
|
---|
| 664 |
|
---|
| 665 | png_read_row(png_ptr, rptr, dptr);
|
---|
| 666 | }
|
---|
| 667 |
|
---|
| 668 | else if (rp != NULL)
|
---|
| 669 | for (i = 0; i < num_rows; i++)
|
---|
| 670 | {
|
---|
| 671 | png_bytep rptr = *rp;
|
---|
| 672 | png_read_row(png_ptr, rptr, NULL);
|
---|
| 673 | rp++;
|
---|
| 674 | }
|
---|
| 675 |
|
---|
| 676 | else if (dp != NULL)
|
---|
| 677 | for (i = 0; i < num_rows; i++)
|
---|
| 678 | {
|
---|
| 679 | png_bytep dptr = *dp;
|
---|
| 680 | png_read_row(png_ptr, NULL, dptr);
|
---|
| 681 | dp++;
|
---|
| 682 | }
|
---|
| 683 | }
|
---|
| 684 | #endif /* SEQUENTIAL_READ */
|
---|
| 685 |
|
---|
| 686 | #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
---|
| 687 | /* Read the entire image. If the image has an alpha channel or a tRNS
|
---|
| 688 | * chunk, and you have called png_handle_alpha()[*], you will need to
|
---|
| 689 | * initialize the image to the current image that PNG will be overlaying.
|
---|
| 690 | * We set the num_rows again here, in case it was incorrectly set in
|
---|
| 691 | * png_read_start_row() by a call to png_read_update_info() or
|
---|
| 692 | * png_start_read_image() if png_set_interlace_handling() wasn't called
|
---|
| 693 | * prior to either of these functions like it should have been. You can
|
---|
| 694 | * only call this function once. If you desire to have an image for
|
---|
| 695 | * each pass of a interlaced image, use png_read_rows() instead.
|
---|
| 696 | *
|
---|
| 697 | * [*] png_handle_alpha() does not exist yet, as of this version of libpng
|
---|
| 698 | */
|
---|
| 699 | void PNGAPI
|
---|
| 700 | png_read_image(png_structrp png_ptr, png_bytepp image)
|
---|
| 701 | {
|
---|
| 702 | png_uint_32 i, image_height;
|
---|
| 703 | int pass, j;
|
---|
| 704 | png_bytepp rp;
|
---|
| 705 |
|
---|
| 706 | png_debug(1, "in png_read_image");
|
---|
| 707 |
|
---|
| 708 | if (png_ptr == NULL)
|
---|
| 709 | return;
|
---|
| 710 |
|
---|
| 711 | #ifdef PNG_READ_INTERLACING_SUPPORTED
|
---|
| 712 | if ((png_ptr->flags & PNG_FLAG_ROW_INIT) == 0)
|
---|
| 713 | {
|
---|
| 714 | pass = png_set_interlace_handling(png_ptr);
|
---|
| 715 | /* And make sure transforms are initialized. */
|
---|
| 716 | png_start_read_image(png_ptr);
|
---|
| 717 | }
|
---|
| 718 | else
|
---|
| 719 | {
|
---|
| 720 | if (png_ptr->interlaced != 0 &&
|
---|
| 721 | (png_ptr->transformations & PNG_INTERLACE) == 0)
|
---|
| 722 | {
|
---|
| 723 | /* Caller called png_start_read_image or png_read_update_info without
|
---|
| 724 | * first turning on the PNG_INTERLACE transform. We can fix this here,
|
---|
| 725 | * but the caller should do it!
|
---|
| 726 | */
|
---|
| 727 | png_warning(png_ptr, "Interlace handling should be turned on when "
|
---|
| 728 | "using png_read_image");
|
---|
| 729 | /* Make sure this is set correctly */
|
---|
| 730 | png_ptr->num_rows = png_ptr->height;
|
---|
| 731 | }
|
---|
| 732 |
|
---|
| 733 | /* Obtain the pass number, which also turns on the PNG_INTERLACE flag in
|
---|
| 734 | * the above error case.
|
---|
| 735 | */
|
---|
| 736 | pass = png_set_interlace_handling(png_ptr);
|
---|
| 737 | }
|
---|
| 738 | #else
|
---|
| 739 | if (png_ptr->interlaced)
|
---|
| 740 | png_error(png_ptr,
|
---|
| 741 | "Cannot read interlaced image -- interlace handler disabled");
|
---|
| 742 |
|
---|
| 743 | pass = 1;
|
---|
| 744 | #endif
|
---|
| 745 |
|
---|
| 746 | image_height=png_ptr->height;
|
---|
| 747 |
|
---|
| 748 | for (j = 0; j < pass; j++)
|
---|
| 749 | {
|
---|
| 750 | rp = image;
|
---|
| 751 | for (i = 0; i < image_height; i++)
|
---|
| 752 | {
|
---|
| 753 | png_read_row(png_ptr, *rp, NULL);
|
---|
| 754 | rp++;
|
---|
| 755 | }
|
---|
| 756 | }
|
---|
| 757 | }
|
---|
| 758 | #endif /* SEQUENTIAL_READ */
|
---|
| 759 |
|
---|
| 760 | #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
---|
| 761 | /* Read the end of the PNG file. Will not read past the end of the
|
---|
| 762 | * file, will verify the end is accurate, and will read any comments
|
---|
| 763 | * or time information at the end of the file, if info is not NULL.
|
---|
| 764 | */
|
---|
| 765 | void PNGAPI
|
---|
| 766 | png_read_end(png_structrp png_ptr, png_inforp info_ptr)
|
---|
| 767 | {
|
---|
| 768 | #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
|
---|
| 769 | int keep;
|
---|
| 770 | #endif
|
---|
| 771 |
|
---|
| 772 | png_debug(1, "in png_read_end");
|
---|
| 773 |
|
---|
| 774 | if (png_ptr == NULL)
|
---|
| 775 | return;
|
---|
| 776 |
|
---|
| 777 | /* If png_read_end is called in the middle of reading the rows there may
|
---|
| 778 | * still be pending IDAT data and an owned zstream. Deal with this here.
|
---|
| 779 | */
|
---|
| 780 | #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
|
---|
| 781 | if (png_chunk_unknown_handling(png_ptr, png_IDAT) == 0)
|
---|
| 782 | #endif
|
---|
| 783 | png_read_finish_IDAT(png_ptr);
|
---|
| 784 |
|
---|
| 785 | #ifdef PNG_READ_CHECK_FOR_INVALID_INDEX_SUPPORTED
|
---|
| 786 | /* Report invalid palette index; added at libng-1.5.10 */
|
---|
| 787 | if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
|
---|
| 788 | png_ptr->num_palette_max > png_ptr->num_palette)
|
---|
| 789 | png_benign_error(png_ptr, "Read palette index exceeding num_palette");
|
---|
| 790 | #endif
|
---|
| 791 |
|
---|
| 792 | do
|
---|
| 793 | {
|
---|
| 794 | png_uint_32 length = png_read_chunk_header(png_ptr);
|
---|
| 795 | png_uint_32 chunk_name = png_ptr->chunk_name;
|
---|
| 796 |
|
---|
| 797 | if (chunk_name != png_IDAT)
|
---|
| 798 | png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
|
---|
| 799 |
|
---|
| 800 | if (chunk_name == png_IEND)
|
---|
| 801 | png_handle_IEND(png_ptr, info_ptr, length);
|
---|
| 802 |
|
---|
| 803 | else if (chunk_name == png_IHDR)
|
---|
| 804 | png_handle_IHDR(png_ptr, info_ptr, length);
|
---|
| 805 |
|
---|
| 806 | else if (info_ptr == NULL)
|
---|
| 807 | png_crc_finish(png_ptr, length);
|
---|
| 808 |
|
---|
| 809 | #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
|
---|
| 810 | else if ((keep = png_chunk_unknown_handling(png_ptr, chunk_name)) != 0)
|
---|
| 811 | {
|
---|
| 812 | if (chunk_name == png_IDAT)
|
---|
| 813 | {
|
---|
| 814 | if ((length > 0 && !(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED))
|
---|
| 815 | || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) != 0)
|
---|
| 816 | png_benign_error(png_ptr, ".Too many IDATs found");
|
---|
| 817 | }
|
---|
| 818 | png_handle_unknown(png_ptr, info_ptr, length, keep);
|
---|
| 819 | if (chunk_name == png_PLTE)
|
---|
| 820 | png_ptr->mode |= PNG_HAVE_PLTE;
|
---|
| 821 | }
|
---|
| 822 | #endif
|
---|
| 823 |
|
---|
| 824 | else if (chunk_name == png_IDAT)
|
---|
| 825 | {
|
---|
| 826 | /* Zero length IDATs are legal after the last IDAT has been
|
---|
| 827 | * read, but not after other chunks have been read. 1.6 does not
|
---|
| 828 | * always read all the deflate data; specifically it cannot be relied
|
---|
| 829 | * upon to read the Adler32 at the end. If it doesn't ignore IDAT
|
---|
| 830 | * chunks which are longer than zero as well:
|
---|
| 831 | */
|
---|
| 832 | if ((length > 0 && !(png_ptr->flags & PNG_FLAG_ZSTREAM_ENDED))
|
---|
| 833 | || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT) != 0)
|
---|
| 834 | png_benign_error(png_ptr, "..Too many IDATs found");
|
---|
| 835 |
|
---|
| 836 | png_crc_finish(png_ptr, length);
|
---|
| 837 | }
|
---|
| 838 | else if (chunk_name == png_PLTE)
|
---|
| 839 | png_handle_PLTE(png_ptr, info_ptr, length);
|
---|
| 840 |
|
---|
| 841 | #ifdef PNG_READ_bKGD_SUPPORTED
|
---|
| 842 | else if (chunk_name == png_bKGD)
|
---|
| 843 | png_handle_bKGD(png_ptr, info_ptr, length);
|
---|
| 844 | #endif
|
---|
| 845 |
|
---|
| 846 | #ifdef PNG_READ_cHRM_SUPPORTED
|
---|
| 847 | else if (chunk_name == png_cHRM)
|
---|
| 848 | png_handle_cHRM(png_ptr, info_ptr, length);
|
---|
| 849 | #endif
|
---|
| 850 |
|
---|
| 851 | #ifdef PNG_READ_eXIf_SUPPORTED
|
---|
| 852 | else if (chunk_name == png_eXIf)
|
---|
| 853 | png_handle_eXIf(png_ptr, info_ptr, length);
|
---|
| 854 | #endif
|
---|
| 855 |
|
---|
| 856 | #ifdef PNG_READ_gAMA_SUPPORTED
|
---|
| 857 | else if (chunk_name == png_gAMA)
|
---|
| 858 | png_handle_gAMA(png_ptr, info_ptr, length);
|
---|
| 859 | #endif
|
---|
| 860 |
|
---|
| 861 | #ifdef PNG_READ_hIST_SUPPORTED
|
---|
| 862 | else if (chunk_name == png_hIST)
|
---|
| 863 | png_handle_hIST(png_ptr, info_ptr, length);
|
---|
| 864 | #endif
|
---|
| 865 |
|
---|
| 866 | #ifdef PNG_READ_oFFs_SUPPORTED
|
---|
| 867 | else if (chunk_name == png_oFFs)
|
---|
| 868 | png_handle_oFFs(png_ptr, info_ptr, length);
|
---|
| 869 | #endif
|
---|
| 870 |
|
---|
| 871 | #ifdef PNG_READ_pCAL_SUPPORTED
|
---|
| 872 | else if (chunk_name == png_pCAL)
|
---|
| 873 | png_handle_pCAL(png_ptr, info_ptr, length);
|
---|
| 874 | #endif
|
---|
| 875 |
|
---|
| 876 | #ifdef PNG_READ_sCAL_SUPPORTED
|
---|
| 877 | else if (chunk_name == png_sCAL)
|
---|
| 878 | png_handle_sCAL(png_ptr, info_ptr, length);
|
---|
| 879 | #endif
|
---|
| 880 |
|
---|
| 881 | #ifdef PNG_READ_pHYs_SUPPORTED
|
---|
| 882 | else if (chunk_name == png_pHYs)
|
---|
| 883 | png_handle_pHYs(png_ptr, info_ptr, length);
|
---|
| 884 | #endif
|
---|
| 885 |
|
---|
| 886 | #ifdef PNG_READ_sBIT_SUPPORTED
|
---|
| 887 | else if (chunk_name == png_sBIT)
|
---|
| 888 | png_handle_sBIT(png_ptr, info_ptr, length);
|
---|
| 889 | #endif
|
---|
| 890 |
|
---|
| 891 | #ifdef PNG_READ_sRGB_SUPPORTED
|
---|
| 892 | else if (chunk_name == png_sRGB)
|
---|
| 893 | png_handle_sRGB(png_ptr, info_ptr, length);
|
---|
| 894 | #endif
|
---|
| 895 |
|
---|
| 896 | #ifdef PNG_READ_iCCP_SUPPORTED
|
---|
| 897 | else if (chunk_name == png_iCCP)
|
---|
| 898 | png_handle_iCCP(png_ptr, info_ptr, length);
|
---|
| 899 | #endif
|
---|
| 900 |
|
---|
| 901 | #ifdef PNG_READ_sPLT_SUPPORTED
|
---|
| 902 | else if (chunk_name == png_sPLT)
|
---|
| 903 | png_handle_sPLT(png_ptr, info_ptr, length);
|
---|
| 904 | #endif
|
---|
| 905 |
|
---|
| 906 | #ifdef PNG_READ_tEXt_SUPPORTED
|
---|
| 907 | else if (chunk_name == png_tEXt)
|
---|
| 908 | png_handle_tEXt(png_ptr, info_ptr, length);
|
---|
| 909 | #endif
|
---|
| 910 |
|
---|
| 911 | #ifdef PNG_READ_tIME_SUPPORTED
|
---|
| 912 | else if (chunk_name == png_tIME)
|
---|
| 913 | png_handle_tIME(png_ptr, info_ptr, length);
|
---|
| 914 | #endif
|
---|
| 915 |
|
---|
| 916 | #ifdef PNG_READ_tRNS_SUPPORTED
|
---|
| 917 | else if (chunk_name == png_tRNS)
|
---|
| 918 | png_handle_tRNS(png_ptr, info_ptr, length);
|
---|
| 919 | #endif
|
---|
| 920 |
|
---|
| 921 | #ifdef PNG_READ_zTXt_SUPPORTED
|
---|
| 922 | else if (chunk_name == png_zTXt)
|
---|
| 923 | png_handle_zTXt(png_ptr, info_ptr, length);
|
---|
| 924 | #endif
|
---|
| 925 |
|
---|
| 926 | #ifdef PNG_READ_iTXt_SUPPORTED
|
---|
| 927 | else if (chunk_name == png_iTXt)
|
---|
| 928 | png_handle_iTXt(png_ptr, info_ptr, length);
|
---|
| 929 | #endif
|
---|
| 930 |
|
---|
| 931 | else
|
---|
| 932 | png_handle_unknown(png_ptr, info_ptr, length,
|
---|
| 933 | PNG_HANDLE_CHUNK_AS_DEFAULT);
|
---|
| 934 | } while ((png_ptr->mode & PNG_HAVE_IEND) == 0);
|
---|
| 935 | }
|
---|
| 936 | #endif /* SEQUENTIAL_READ */
|
---|
| 937 |
|
---|
| 938 | /* Free all memory used in the read struct */
|
---|
| 939 | static void
|
---|
| 940 | png_read_destroy(png_structrp png_ptr)
|
---|
| 941 | {
|
---|
| 942 | png_debug(1, "in png_read_destroy");
|
---|
| 943 |
|
---|
| 944 | #ifdef PNG_READ_GAMMA_SUPPORTED
|
---|
| 945 | png_destroy_gamma_table(png_ptr);
|
---|
| 946 | #endif
|
---|
| 947 |
|
---|
| 948 | png_free(png_ptr, png_ptr->big_row_buf);
|
---|
| 949 | png_ptr->big_row_buf = NULL;
|
---|
| 950 | png_free(png_ptr, png_ptr->big_prev_row);
|
---|
| 951 | png_ptr->big_prev_row = NULL;
|
---|
| 952 | png_free(png_ptr, png_ptr->read_buffer);
|
---|
| 953 | png_ptr->read_buffer = NULL;
|
---|
| 954 |
|
---|
| 955 | #ifdef PNG_READ_QUANTIZE_SUPPORTED
|
---|
| 956 | png_free(png_ptr, png_ptr->palette_lookup);
|
---|
| 957 | png_ptr->palette_lookup = NULL;
|
---|
| 958 | png_free(png_ptr, png_ptr->quantize_index);
|
---|
| 959 | png_ptr->quantize_index = NULL;
|
---|
| 960 | #endif
|
---|
| 961 |
|
---|
| 962 | if ((png_ptr->free_me & PNG_FREE_PLTE) != 0)
|
---|
| 963 | {
|
---|
| 964 | png_zfree(png_ptr, png_ptr->palette);
|
---|
| 965 | png_ptr->palette = NULL;
|
---|
| 966 | }
|
---|
| 967 | png_ptr->free_me &= ~PNG_FREE_PLTE;
|
---|
| 968 |
|
---|
| 969 | #if defined(PNG_tRNS_SUPPORTED) || \
|
---|
| 970 | defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
|
---|
| 971 | if ((png_ptr->free_me & PNG_FREE_TRNS) != 0)
|
---|
| 972 | {
|
---|
| 973 | png_free(png_ptr, png_ptr->trans_alpha);
|
---|
| 974 | png_ptr->trans_alpha = NULL;
|
---|
| 975 | }
|
---|
| 976 | png_ptr->free_me &= ~PNG_FREE_TRNS;
|
---|
| 977 | #endif
|
---|
| 978 |
|
---|
| 979 | inflateEnd(&png_ptr->zstream);
|
---|
| 980 |
|
---|
| 981 | #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
|
---|
| 982 | png_free(png_ptr, png_ptr->save_buffer);
|
---|
| 983 | png_ptr->save_buffer = NULL;
|
---|
| 984 | #endif
|
---|
| 985 |
|
---|
| 986 | #if defined(PNG_STORE_UNKNOWN_CHUNKS_SUPPORTED) && \
|
---|
| 987 | defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
|
---|
| 988 | png_free(png_ptr, png_ptr->unknown_chunk.data);
|
---|
| 989 | png_ptr->unknown_chunk.data = NULL;
|
---|
| 990 | #endif
|
---|
| 991 |
|
---|
| 992 | #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
|
---|
| 993 | png_free(png_ptr, png_ptr->chunk_list);
|
---|
| 994 | png_ptr->chunk_list = NULL;
|
---|
| 995 | #endif
|
---|
| 996 |
|
---|
| 997 | #if defined(PNG_READ_EXPAND_SUPPORTED) && \
|
---|
| 998 | defined(PNG_ARM_NEON_IMPLEMENTATION)
|
---|
| 999 | png_free(png_ptr, png_ptr->riffled_palette);
|
---|
| 1000 | png_ptr->riffled_palette = NULL;
|
---|
| 1001 | #endif
|
---|
| 1002 |
|
---|
| 1003 | /* NOTE: the 'setjmp' buffer may still be allocated and the memory and error
|
---|
| 1004 | * callbacks are still set at this point. They are required to complete the
|
---|
| 1005 | * destruction of the png_struct itself.
|
---|
| 1006 | */
|
---|
| 1007 | }
|
---|
| 1008 |
|
---|
| 1009 | /* Free all memory used by the read */
|
---|
| 1010 | void PNGAPI
|
---|
| 1011 | png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr,
|
---|
| 1012 | png_infopp end_info_ptr_ptr)
|
---|
| 1013 | {
|
---|
| 1014 | png_structrp png_ptr = NULL;
|
---|
| 1015 |
|
---|
| 1016 | png_debug(1, "in png_destroy_read_struct");
|
---|
| 1017 |
|
---|
| 1018 | if (png_ptr_ptr != NULL)
|
---|
| 1019 | png_ptr = *png_ptr_ptr;
|
---|
| 1020 |
|
---|
| 1021 | if (png_ptr == NULL)
|
---|
| 1022 | return;
|
---|
| 1023 |
|
---|
| 1024 | /* libpng 1.6.0: use the API to destroy info structs to ensure consistent
|
---|
| 1025 | * behavior. Prior to 1.6.0 libpng did extra 'info' destruction in this API.
|
---|
| 1026 | * The extra was, apparently, unnecessary yet this hides memory leak bugs.
|
---|
| 1027 | */
|
---|
| 1028 | png_destroy_info_struct(png_ptr, end_info_ptr_ptr);
|
---|
| 1029 | png_destroy_info_struct(png_ptr, info_ptr_ptr);
|
---|
| 1030 |
|
---|
| 1031 | *png_ptr_ptr = NULL;
|
---|
| 1032 | png_read_destroy(png_ptr);
|
---|
| 1033 | png_destroy_png_struct(png_ptr);
|
---|
| 1034 | }
|
---|
| 1035 |
|
---|
| 1036 | void PNGAPI
|
---|
| 1037 | png_set_read_status_fn(png_structrp png_ptr, png_read_status_ptr read_row_fn)
|
---|
| 1038 | {
|
---|
| 1039 | if (png_ptr == NULL)
|
---|
| 1040 | return;
|
---|
| 1041 |
|
---|
| 1042 | png_ptr->read_row_fn = read_row_fn;
|
---|
| 1043 | }
|
---|
| 1044 |
|
---|
| 1045 |
|
---|
| 1046 | #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
|
---|
| 1047 | #ifdef PNG_INFO_IMAGE_SUPPORTED
|
---|
| 1048 | void PNGAPI
|
---|
| 1049 | png_read_png(png_structrp png_ptr, png_inforp info_ptr,
|
---|
| 1050 | int transforms, voidp params)
|
---|
| 1051 | {
|
---|
| 1052 | if (png_ptr == NULL || info_ptr == NULL)
|
---|
| 1053 | return;
|
---|
| 1054 |
|
---|
| 1055 | /* png_read_info() gives us all of the information from the
|
---|
| 1056 | * PNG file before the first IDAT (image data chunk).
|
---|
| 1057 | */
|
---|
| 1058 | png_read_info(png_ptr, info_ptr);
|
---|
| 1059 | if (info_ptr->height > PNG_UINT_32_MAX/(sizeof (png_bytep)))
|
---|
| 1060 | png_error(png_ptr, "Image is too high to process with png_read_png()");
|
---|
| 1061 |
|
---|
| 1062 | /* -------------- image transformations start here ------------------- */
|
---|
| 1063 | /* libpng 1.6.10: add code to cause a png_app_error if a selected TRANSFORM
|
---|
| 1064 | * is not implemented. This will only happen in de-configured (non-default)
|
---|
| 1065 | * libpng builds. The results can be unexpected - png_read_png may return
|
---|
| 1066 | * short or mal-formed rows because the transform is skipped.
|
---|
| 1067 | */
|
---|
| 1068 |
|
---|
| 1069 | /* Tell libpng to strip 16-bit/color files down to 8 bits per color.
|
---|
| 1070 | */
|
---|
| 1071 | if ((transforms & PNG_TRANSFORM_SCALE_16) != 0)
|
---|
| 1072 | /* Added at libpng-1.5.4. "strip_16" produces the same result that it
|
---|
| 1073 | * did in earlier versions, while "scale_16" is now more accurate.
|
---|
| 1074 | */
|
---|
| 1075 | #ifdef PNG_READ_SCALE_16_TO_8_SUPPORTED
|
---|
| 1076 | png_set_scale_16(png_ptr);
|
---|
| 1077 | #else
|
---|
| 1078 | png_app_error(png_ptr, "PNG_TRANSFORM_SCALE_16 not supported");
|
---|
| 1079 | #endif
|
---|
| 1080 |
|
---|
| 1081 | /* If both SCALE and STRIP are required pngrtran will effectively cancel the
|
---|
| 1082 | * latter by doing SCALE first. This is ok and allows apps not to check for
|
---|
| 1083 | * which is supported to get the right answer.
|
---|
| 1084 | */
|
---|
| 1085 | if ((transforms & PNG_TRANSFORM_STRIP_16) != 0)
|
---|
| 1086 | #ifdef PNG_READ_STRIP_16_TO_8_SUPPORTED
|
---|
| 1087 | png_set_strip_16(png_ptr);
|
---|
| 1088 | #else
|
---|
| 1089 | png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_16 not supported");
|
---|
| 1090 | #endif
|
---|
| 1091 |
|
---|
| 1092 | /* Strip alpha bytes from the input data without combining with
|
---|
| 1093 | * the background (not recommended).
|
---|
| 1094 | */
|
---|
| 1095 | if ((transforms & PNG_TRANSFORM_STRIP_ALPHA) != 0)
|
---|
| 1096 | #ifdef PNG_READ_STRIP_ALPHA_SUPPORTED
|
---|
| 1097 | png_set_strip_alpha(png_ptr);
|
---|
| 1098 | #else
|
---|
| 1099 | png_app_error(png_ptr, "PNG_TRANSFORM_STRIP_ALPHA not supported");
|
---|
| 1100 | #endif
|
---|
| 1101 |
|
---|
| 1102 | /* Extract multiple pixels with bit depths of 1, 2, or 4 from a single
|
---|
| 1103 | * byte into separate bytes (useful for paletted and grayscale images).
|
---|
| 1104 | */
|
---|
| 1105 | if ((transforms & PNG_TRANSFORM_PACKING) != 0)
|
---|
| 1106 | #ifdef PNG_READ_PACK_SUPPORTED
|
---|
| 1107 | png_set_packing(png_ptr);
|
---|
| 1108 | #else
|
---|
| 1109 | png_app_error(png_ptr, "PNG_TRANSFORM_PACKING not supported");
|
---|
| 1110 | #endif
|
---|
| 1111 |
|
---|
| 1112 | /* Change the order of packed pixels to least significant bit first
|
---|
| 1113 | * (not useful if you are using png_set_packing).
|
---|
| 1114 | */
|
---|
| 1115 | if ((transforms & PNG_TRANSFORM_PACKSWAP) != 0)
|
---|
| 1116 | #ifdef PNG_READ_PACKSWAP_SUPPORTED
|
---|
| 1117 | png_set_packswap(png_ptr);
|
---|
| 1118 | #else
|
---|
| 1119 | png_app_error(png_ptr, "PNG_TRANSFORM_PACKSWAP not supported");
|
---|
| 1120 | #endif
|
---|
| 1121 |
|
---|
| 1122 | /* Expand paletted colors into true RGB triplets
|
---|
| 1123 | * Expand grayscale images to full 8 bits from 1, 2, or 4 bits/pixel
|
---|
| 1124 | * Expand paletted or RGB images with transparency to full alpha
|
---|
| 1125 | * channels so the data will be available as RGBA quartets.
|
---|
| 1126 | */
|
---|
| 1127 | if ((transforms & PNG_TRANSFORM_EXPAND) != 0)
|
---|
| 1128 | #ifdef PNG_READ_EXPAND_SUPPORTED
|
---|
| 1129 | png_set_expand(png_ptr);
|
---|
| 1130 | #else
|
---|
| 1131 | png_app_error(png_ptr, "PNG_TRANSFORM_EXPAND not supported");
|
---|
| 1132 | #endif
|
---|
| 1133 |
|
---|
| 1134 | /* We don't handle background color or gamma transformation or quantizing.
|
---|
| 1135 | */
|
---|
| 1136 |
|
---|
| 1137 | /* Invert monochrome files to have 0 as white and 1 as black
|
---|
| 1138 | */
|
---|
| 1139 | if ((transforms & PNG_TRANSFORM_INVERT_MONO) != 0)
|
---|
| 1140 | #ifdef PNG_READ_INVERT_SUPPORTED
|
---|
| 1141 | png_set_invert_mono(png_ptr);
|
---|
| 1142 | #else
|
---|
| 1143 | png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_MONO not supported");
|
---|
| 1144 | #endif
|
---|
| 1145 |
|
---|
| 1146 | /* If you want to shift the pixel values from the range [0,255] or
|
---|
| 1147 | * [0,65535] to the original [0,7] or [0,31], or whatever range the
|
---|
| 1148 | * colors were originally in:
|
---|
| 1149 | */
|
---|
| 1150 | if ((transforms & PNG_TRANSFORM_SHIFT) != 0)
|
---|
| 1151 | #ifdef PNG_READ_SHIFT_SUPPORTED
|
---|
| 1152 | if ((info_ptr->valid & PNG_INFO_sBIT) != 0)
|
---|
| 1153 | png_set_shift(png_ptr, &info_ptr->sig_bit);
|
---|
| 1154 | #else
|
---|
| 1155 | png_app_error(png_ptr, "PNG_TRANSFORM_SHIFT not supported");
|
---|
| 1156 | #endif
|
---|
| 1157 |
|
---|
| 1158 | /* Flip the RGB pixels to BGR (or RGBA to BGRA) */
|
---|
| 1159 | if ((transforms & PNG_TRANSFORM_BGR) != 0)
|
---|
| 1160 | #ifdef PNG_READ_BGR_SUPPORTED
|
---|
| 1161 | png_set_bgr(png_ptr);
|
---|
| 1162 | #else
|
---|
| 1163 | png_app_error(png_ptr, "PNG_TRANSFORM_BGR not supported");
|
---|
| 1164 | #endif
|
---|
| 1165 |
|
---|
| 1166 | /* Swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR) */
|
---|
| 1167 | if ((transforms & PNG_TRANSFORM_SWAP_ALPHA) != 0)
|
---|
| 1168 | #ifdef PNG_READ_SWAP_ALPHA_SUPPORTED
|
---|
| 1169 | png_set_swap_alpha(png_ptr);
|
---|
| 1170 | #else
|
---|
| 1171 | png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ALPHA not supported");
|
---|
| 1172 | #endif
|
---|
| 1173 |
|
---|
| 1174 | /* Swap bytes of 16-bit files to least significant byte first */
|
---|
| 1175 | if ((transforms & PNG_TRANSFORM_SWAP_ENDIAN) != 0)
|
---|
| 1176 | #ifdef PNG_READ_SWAP_SUPPORTED
|
---|
| 1177 | png_set_swap(png_ptr);
|
---|
| 1178 | #else
|
---|
| 1179 | png_app_error(png_ptr, "PNG_TRANSFORM_SWAP_ENDIAN not supported");
|
---|
| 1180 | #endif
|
---|
| 1181 |
|
---|
| 1182 | /* Added at libpng-1.2.41 */
|
---|
| 1183 | /* Invert the alpha channel from opacity to transparency */
|
---|
| 1184 | if ((transforms & PNG_TRANSFORM_INVERT_ALPHA) != 0)
|
---|
| 1185 | #ifdef PNG_READ_INVERT_ALPHA_SUPPORTED
|
---|
| 1186 | png_set_invert_alpha(png_ptr);
|
---|
| 1187 | #else
|
---|
| 1188 | png_app_error(png_ptr, "PNG_TRANSFORM_INVERT_ALPHA not supported");
|
---|
| 1189 | #endif
|
---|
| 1190 |
|
---|
| 1191 | /* Added at libpng-1.2.41 */
|
---|
| 1192 | /* Expand grayscale image to RGB */
|
---|
| 1193 | if ((transforms & PNG_TRANSFORM_GRAY_TO_RGB) != 0)
|
---|
| 1194 | #ifdef PNG_READ_GRAY_TO_RGB_SUPPORTED
|
---|
| 1195 | png_set_gray_to_rgb(png_ptr);
|
---|
| 1196 | #else
|
---|
| 1197 | png_app_error(png_ptr, "PNG_TRANSFORM_GRAY_TO_RGB not supported");
|
---|
| 1198 | #endif
|
---|
| 1199 |
|
---|
| 1200 | /* Added at libpng-1.5.4 */
|
---|
| 1201 | if ((transforms & PNG_TRANSFORM_EXPAND_16) != 0)
|
---|
| 1202 | #ifdef PNG_READ_EXPAND_16_SUPPORTED
|
---|
| 1203 | png_set_expand_16(png_ptr);
|
---|
| 1204 | #else
|
---|
| 1205 | png_app_error(png_ptr, "PNG_TRANSFORM_EXPAND_16 not supported");
|
---|
| 1206 | #endif
|
---|
| 1207 |
|
---|
| 1208 | /* We don't handle adding filler bytes */
|
---|
| 1209 |
|
---|
| 1210 | /* We use png_read_image and rely on that for interlace handling, but we also
|
---|
| 1211 | * call png_read_update_info therefore must turn on interlace handling now:
|
---|
| 1212 | */
|
---|
| 1213 | (void)png_set_interlace_handling(png_ptr);
|
---|
| 1214 |
|
---|
| 1215 | /* Optional call to gamma correct and add the background to the palette
|
---|
| 1216 | * and update info structure. REQUIRED if you are expecting libpng to
|
---|
| 1217 | * update the palette for you (i.e., you selected such a transform above).
|
---|
| 1218 | */
|
---|
| 1219 | png_read_update_info(png_ptr, info_ptr);
|
---|
| 1220 |
|
---|
| 1221 | /* -------------- image transformations end here ------------------- */
|
---|
| 1222 |
|
---|
| 1223 | png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
|
---|
| 1224 | if (info_ptr->row_pointers == NULL)
|
---|
| 1225 | {
|
---|
| 1226 | png_uint_32 iptr;
|
---|
| 1227 |
|
---|
| 1228 | info_ptr->row_pointers = png_voidcast(png_bytepp, png_malloc(png_ptr,
|
---|
| 1229 | info_ptr->height * (sizeof (png_bytep))));
|
---|
| 1230 |
|
---|
| 1231 | for (iptr=0; iptr<info_ptr->height; iptr++)
|
---|
| 1232 | info_ptr->row_pointers[iptr] = NULL;
|
---|
| 1233 |
|
---|
| 1234 | info_ptr->free_me |= PNG_FREE_ROWS;
|
---|
| 1235 |
|
---|
| 1236 | for (iptr = 0; iptr < info_ptr->height; iptr++)
|
---|
| 1237 | info_ptr->row_pointers[iptr] = png_voidcast(png_bytep,
|
---|
| 1238 | png_malloc(png_ptr, info_ptr->rowbytes));
|
---|
| 1239 | }
|
---|
| 1240 |
|
---|
| 1241 | png_read_image(png_ptr, info_ptr->row_pointers);
|
---|
| 1242 | info_ptr->valid |= PNG_INFO_IDAT;
|
---|
| 1243 |
|
---|
| 1244 | /* Read rest of file, and get additional chunks in info_ptr - REQUIRED */
|
---|
| 1245 | png_read_end(png_ptr, info_ptr);
|
---|
| 1246 |
|
---|
| 1247 | PNG_UNUSED(params)
|
---|
| 1248 | }
|
---|
| 1249 | #endif /* INFO_IMAGE */
|
---|
| 1250 | #endif /* SEQUENTIAL_READ */
|
---|
| 1251 |
|
---|
| 1252 | #ifdef PNG_SIMPLIFIED_READ_SUPPORTED
|
---|
| 1253 | /* SIMPLIFIED READ
|
---|
| 1254 | *
|
---|
| 1255 | * This code currently relies on the sequential reader, though it could easily
|
---|
| 1256 | * be made to work with the progressive one.
|
---|
| 1257 | */
|
---|
| 1258 | /* Arguments to png_image_finish_read: */
|
---|
| 1259 |
|
---|
| 1260 | /* Encoding of PNG data (used by the color-map code) */
|
---|
| 1261 | # define P_NOTSET 0 /* File encoding not yet known */
|
---|
| 1262 | # define P_sRGB 1 /* 8-bit encoded to sRGB gamma */
|
---|
| 1263 | # define P_LINEAR 2 /* 16-bit linear: not encoded, NOT pre-multiplied! */
|
---|
| 1264 | # define P_FILE 3 /* 8-bit encoded to file gamma, not sRGB or linear */
|
---|
| 1265 | # define P_LINEAR8 4 /* 8-bit linear: only from a file value */
|
---|
| 1266 |
|
---|
| 1267 | /* Color-map processing: after libpng has run on the PNG image further
|
---|
| 1268 | * processing may be needed to convert the data to color-map indices.
|
---|
| 1269 | */
|
---|
| 1270 | #define PNG_CMAP_NONE 0
|
---|
| 1271 | #define PNG_CMAP_GA 1 /* Process GA data to a color-map with alpha */
|
---|
| 1272 | #define PNG_CMAP_TRANS 2 /* Process GA data to a background index */
|
---|
| 1273 | #define PNG_CMAP_RGB 3 /* Process RGB data */
|
---|
| 1274 | #define PNG_CMAP_RGB_ALPHA 4 /* Process RGBA data */
|
---|
| 1275 |
|
---|
| 1276 | /* The following document where the background is for each processing case. */
|
---|
| 1277 | #define PNG_CMAP_NONE_BACKGROUND 256
|
---|
| 1278 | #define PNG_CMAP_GA_BACKGROUND 231
|
---|
| 1279 | #define PNG_CMAP_TRANS_BACKGROUND 254
|
---|
| 1280 | #define PNG_CMAP_RGB_BACKGROUND 256
|
---|
| 1281 | #define PNG_CMAP_RGB_ALPHA_BACKGROUND 216
|
---|
| 1282 |
|
---|
| 1283 | typedef struct
|
---|
| 1284 | {
|
---|
| 1285 | /* Arguments: */
|
---|
| 1286 | png_imagep image;
|
---|
| 1287 | png_voidp buffer;
|
---|
| 1288 | png_int_32 row_stride;
|
---|
| 1289 | png_voidp colormap;
|
---|
| 1290 | png_const_colorp background;
|
---|
| 1291 | /* Local variables: */
|
---|
| 1292 | png_voidp local_row;
|
---|
| 1293 | png_voidp first_row;
|
---|
| 1294 | ptrdiff_t row_bytes; /* step between rows */
|
---|
| 1295 | int file_encoding; /* E_ values above */
|
---|
| 1296 | png_fixed_point gamma_to_linear; /* For P_FILE, reciprocal of gamma */
|
---|
| 1297 | int colormap_processing; /* PNG_CMAP_ values above */
|
---|
| 1298 | } png_image_read_control;
|
---|
| 1299 |
|
---|
| 1300 | /* Do all the *safe* initialization - 'safe' means that png_error won't be
|
---|
| 1301 | * called, so setting up the jmp_buf is not required. This means that anything
|
---|
| 1302 | * called from here must *not* call png_malloc - it has to call png_malloc_warn
|
---|
| 1303 | * instead so that control is returned safely back to this routine.
|
---|
| 1304 | */
|
---|
| 1305 | static int
|
---|
| 1306 | png_image_read_init(png_imagep image)
|
---|
| 1307 | {
|
---|
| 1308 | if (image->opaque == NULL)
|
---|
| 1309 | {
|
---|
| 1310 | png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, image,
|
---|
| 1311 | png_safe_error, png_safe_warning);
|
---|
| 1312 |
|
---|
| 1313 | /* And set the rest of the structure to NULL to ensure that the various
|
---|
| 1314 | * fields are consistent.
|
---|
| 1315 | */
|
---|
| 1316 | memset(image, 0, (sizeof *image));
|
---|
| 1317 | image->version = PNG_IMAGE_VERSION;
|
---|
| 1318 |
|
---|
| 1319 | if (png_ptr != NULL)
|
---|
| 1320 | {
|
---|
| 1321 | png_infop info_ptr = png_create_info_struct(png_ptr);
|
---|
| 1322 |
|
---|
| 1323 | if (info_ptr != NULL)
|
---|
| 1324 | {
|
---|
| 1325 | png_controlp control = png_voidcast(png_controlp,
|
---|
| 1326 | png_malloc_warn(png_ptr, (sizeof *control)));
|
---|
| 1327 |
|
---|
| 1328 | if (control != NULL)
|
---|
| 1329 | {
|
---|
| 1330 | memset(control, 0, (sizeof *control));
|
---|
| 1331 |
|
---|
| 1332 | control->png_ptr = png_ptr;
|
---|
| 1333 | control->info_ptr = info_ptr;
|
---|
| 1334 | control->for_write = 0;
|
---|
| 1335 |
|
---|
| 1336 | image->opaque = control;
|
---|
| 1337 | return 1;
|
---|
| 1338 | }
|
---|
| 1339 |
|
---|
| 1340 | /* Error clean up */
|
---|
| 1341 | png_destroy_info_struct(png_ptr, &info_ptr);
|
---|
| 1342 | }
|
---|
| 1343 |
|
---|
| 1344 | png_destroy_read_struct(&png_ptr, NULL, NULL);
|
---|
| 1345 | }
|
---|
| 1346 |
|
---|
| 1347 | return png_image_error(image, "png_image_read: out of memory");
|
---|
| 1348 | }
|
---|
| 1349 |
|
---|
| 1350 | return png_image_error(image, "png_image_read: opaque pointer not NULL");
|
---|
| 1351 | }
|
---|
| 1352 |
|
---|
| 1353 | /* Utility to find the base format of a PNG file from a png_struct. */
|
---|
| 1354 | static png_uint_32
|
---|
| 1355 | png_image_format(png_structrp png_ptr)
|
---|
| 1356 | {
|
---|
| 1357 | png_uint_32 format = 0;
|
---|
| 1358 |
|
---|
| 1359 | if ((png_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
|
---|
| 1360 | format |= PNG_FORMAT_FLAG_COLOR;
|
---|
| 1361 |
|
---|
| 1362 | if ((png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
|
---|
| 1363 | format |= PNG_FORMAT_FLAG_ALPHA;
|
---|
| 1364 |
|
---|
| 1365 | /* Use png_ptr here, not info_ptr, because by examination png_handle_tRNS
|
---|
| 1366 | * sets the png_struct fields; that's all we are interested in here. The
|
---|
| 1367 | * precise interaction with an app call to png_set_tRNS and PNG file reading
|
---|
| 1368 | * is unclear.
|
---|
| 1369 | */
|
---|
| 1370 | else if (png_ptr->num_trans > 0)
|
---|
| 1371 | format |= PNG_FORMAT_FLAG_ALPHA;
|
---|
| 1372 |
|
---|
| 1373 | if (png_ptr->bit_depth == 16)
|
---|
| 1374 | format |= PNG_FORMAT_FLAG_LINEAR;
|
---|
| 1375 |
|
---|
| 1376 | if ((png_ptr->color_type & PNG_COLOR_MASK_PALETTE) != 0)
|
---|
| 1377 | format |= PNG_FORMAT_FLAG_COLORMAP;
|
---|
| 1378 |
|
---|
| 1379 | return format;
|
---|
| 1380 | }
|
---|
| 1381 |
|
---|
| 1382 | /* Is the given gamma significantly different from sRGB? The test is the same
|
---|
| 1383 | * one used in pngrtran.c when deciding whether to do gamma correction. The
|
---|
| 1384 | * arithmetic optimizes the division by using the fact that the inverse of the
|
---|
| 1385 | * file sRGB gamma is 2.2
|
---|
| 1386 | */
|
---|
| 1387 | static int
|
---|
| 1388 | png_gamma_not_sRGB(png_fixed_point g)
|
---|
| 1389 | {
|
---|
| 1390 | if (g < PNG_FP_1)
|
---|
| 1391 | {
|
---|
| 1392 | /* An uninitialized gamma is assumed to be sRGB for the simplified API. */
|
---|
| 1393 | if (g == 0)
|
---|
| 1394 | return 0;
|
---|
| 1395 |
|
---|
| 1396 | return png_gamma_significant((g * 11 + 2)/5 /* i.e. *2.2, rounded */);
|
---|
| 1397 | }
|
---|
| 1398 |
|
---|
| 1399 | return 1;
|
---|
| 1400 | }
|
---|
| 1401 |
|
---|
| 1402 | /* Do the main body of a 'png_image_begin_read' function; read the PNG file
|
---|
| 1403 | * header and fill in all the information. This is executed in a safe context,
|
---|
| 1404 | * unlike the init routine above.
|
---|
| 1405 | */
|
---|
| 1406 | static int
|
---|
| 1407 | png_image_read_header(png_voidp argument)
|
---|
| 1408 | {
|
---|
| 1409 | png_imagep image = png_voidcast(png_imagep, argument);
|
---|
| 1410 | png_structrp png_ptr = image->opaque->png_ptr;
|
---|
| 1411 | png_inforp info_ptr = image->opaque->info_ptr;
|
---|
| 1412 |
|
---|
| 1413 | #ifdef PNG_BENIGN_ERRORS_SUPPORTED
|
---|
| 1414 | png_set_benign_errors(png_ptr, 1/*warn*/);
|
---|
| 1415 | #endif
|
---|
| 1416 | png_read_info(png_ptr, info_ptr);
|
---|
| 1417 |
|
---|
| 1418 | /* Do this the fast way; just read directly out of png_struct. */
|
---|
| 1419 | image->width = png_ptr->width;
|
---|
| 1420 | image->height = png_ptr->height;
|
---|
| 1421 |
|
---|
| 1422 | {
|
---|
| 1423 | png_uint_32 format = png_image_format(png_ptr);
|
---|
| 1424 |
|
---|
| 1425 | image->format = format;
|
---|
| 1426 |
|
---|
| 1427 | #ifdef PNG_COLORSPACE_SUPPORTED
|
---|
| 1428 | /* Does the colorspace match sRGB? If there is no color endpoint
|
---|
| 1429 | * (colorant) information assume yes, otherwise require the
|
---|
| 1430 | * 'ENDPOINTS_MATCHP_sRGB' colorspace flag to have been set. If the
|
---|
| 1431 | * colorspace has been determined to be invalid ignore it.
|
---|
| 1432 | */
|
---|
| 1433 | if ((format & PNG_FORMAT_FLAG_COLOR) != 0 && ((png_ptr->colorspace.flags
|
---|
| 1434 | & (PNG_COLORSPACE_HAVE_ENDPOINTS|PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB|
|
---|
| 1435 | PNG_COLORSPACE_INVALID)) == PNG_COLORSPACE_HAVE_ENDPOINTS))
|
---|
| 1436 | image->flags |= PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB;
|
---|
| 1437 | #endif
|
---|
| 1438 | }
|
---|
| 1439 |
|
---|
| 1440 | /* We need the maximum number of entries regardless of the format the
|
---|
| 1441 | * application sets here.
|
---|
| 1442 | */
|
---|
| 1443 | {
|
---|
| 1444 | png_uint_32 cmap_entries;
|
---|
| 1445 |
|
---|
| 1446 | switch (png_ptr->color_type)
|
---|
| 1447 | {
|
---|
| 1448 | case PNG_COLOR_TYPE_GRAY:
|
---|
| 1449 | cmap_entries = 1U << png_ptr->bit_depth;
|
---|
| 1450 | break;
|
---|
| 1451 |
|
---|
| 1452 | case PNG_COLOR_TYPE_PALETTE:
|
---|
| 1453 | cmap_entries = (png_uint_32)png_ptr->num_palette;
|
---|
| 1454 | break;
|
---|
| 1455 |
|
---|
| 1456 | default:
|
---|
| 1457 | cmap_entries = 256;
|
---|
| 1458 | break;
|
---|
| 1459 | }
|
---|
| 1460 |
|
---|
| 1461 | if (cmap_entries > 256)
|
---|
| 1462 | cmap_entries = 256;
|
---|
| 1463 |
|
---|
| 1464 | image->colormap_entries = cmap_entries;
|
---|
| 1465 | }
|
---|
| 1466 |
|
---|
| 1467 | return 1;
|
---|
| 1468 | }
|
---|
| 1469 |
|
---|
| 1470 | #ifdef PNG_STDIO_SUPPORTED
|
---|
| 1471 | int PNGAPI
|
---|
| 1472 | png_image_begin_read_from_stdio(png_imagep image, FILE* file)
|
---|
| 1473 | {
|
---|
| 1474 | if (image != NULL && image->version == PNG_IMAGE_VERSION)
|
---|
| 1475 | {
|
---|
| 1476 | if (file != NULL)
|
---|
| 1477 | {
|
---|
| 1478 | if (png_image_read_init(image) != 0)
|
---|
| 1479 | {
|
---|
| 1480 | /* This is slightly evil, but png_init_io doesn't do anything other
|
---|
| 1481 | * than this and we haven't changed the standard IO functions so
|
---|
| 1482 | * this saves a 'safe' function.
|
---|
| 1483 | */
|
---|
| 1484 | image->opaque->png_ptr->io_ptr = file;
|
---|
| 1485 | return png_safe_execute(image, png_image_read_header, image);
|
---|
| 1486 | }
|
---|
| 1487 | }
|
---|
| 1488 |
|
---|
| 1489 | else
|
---|
| 1490 | return png_image_error(image,
|
---|
| 1491 | "png_image_begin_read_from_stdio: invalid argument");
|
---|
| 1492 | }
|
---|
| 1493 |
|
---|
| 1494 | else if (image != NULL)
|
---|
| 1495 | return png_image_error(image,
|
---|
| 1496 | "png_image_begin_read_from_stdio: incorrect PNG_IMAGE_VERSION");
|
---|
| 1497 |
|
---|
| 1498 | return 0;
|
---|
| 1499 | }
|
---|
| 1500 |
|
---|
| 1501 | int PNGAPI
|
---|
| 1502 | png_image_begin_read_from_file(png_imagep image, const char *file_name)
|
---|
| 1503 | {
|
---|
| 1504 | if (image != NULL && image->version == PNG_IMAGE_VERSION)
|
---|
| 1505 | {
|
---|
| 1506 | if (file_name != NULL)
|
---|
| 1507 | {
|
---|
| 1508 | FILE *fp = fopen(file_name, "rb");
|
---|
| 1509 |
|
---|
| 1510 | if (fp != NULL)
|
---|
| 1511 | {
|
---|
| 1512 | if (png_image_read_init(image) != 0)
|
---|
| 1513 | {
|
---|
| 1514 | image->opaque->png_ptr->io_ptr = fp;
|
---|
| 1515 | image->opaque->owned_file = 1;
|
---|
| 1516 | return png_safe_execute(image, png_image_read_header, image);
|
---|
| 1517 | }
|
---|
| 1518 |
|
---|
| 1519 | /* Clean up: just the opened file. */
|
---|
| 1520 | (void)fclose(fp);
|
---|
| 1521 | }
|
---|
| 1522 |
|
---|
| 1523 | else
|
---|
| 1524 | return png_image_error(image, strerror(errno));
|
---|
| 1525 | }
|
---|
| 1526 |
|
---|
| 1527 | else
|
---|
| 1528 | return png_image_error(image,
|
---|
| 1529 | "png_image_begin_read_from_file: invalid argument");
|
---|
| 1530 | }
|
---|
| 1531 |
|
---|
| 1532 | else if (image != NULL)
|
---|
| 1533 | return png_image_error(image,
|
---|
| 1534 | "png_image_begin_read_from_file: incorrect PNG_IMAGE_VERSION");
|
---|
| 1535 |
|
---|
| 1536 | return 0;
|
---|
| 1537 | }
|
---|
| 1538 | #endif /* STDIO */
|
---|
| 1539 |
|
---|
| 1540 | static void PNGCBAPI
|
---|
| 1541 | png_image_memory_read(png_structp png_ptr, png_bytep out, size_t need)
|
---|
| 1542 | {
|
---|
| 1543 | if (png_ptr != NULL)
|
---|
| 1544 | {
|
---|
| 1545 | png_imagep image = png_voidcast(png_imagep, png_ptr->io_ptr);
|
---|
| 1546 | if (image != NULL)
|
---|
| 1547 | {
|
---|
| 1548 | png_controlp cp = image->opaque;
|
---|
| 1549 | if (cp != NULL)
|
---|
| 1550 | {
|
---|
| 1551 | png_const_bytep memory = cp->memory;
|
---|
| 1552 | size_t size = cp->size;
|
---|
| 1553 |
|
---|
| 1554 | if (memory != NULL && size >= need)
|
---|
| 1555 | {
|
---|
| 1556 | memcpy(out, memory, need);
|
---|
| 1557 | cp->memory = memory + need;
|
---|
| 1558 | cp->size = size - need;
|
---|
| 1559 | return;
|
---|
| 1560 | }
|
---|
| 1561 |
|
---|
| 1562 | png_error(png_ptr, "read beyond end of data");
|
---|
| 1563 | }
|
---|
| 1564 | }
|
---|
| 1565 |
|
---|
| 1566 | png_error(png_ptr, "invalid memory read");
|
---|
| 1567 | }
|
---|
| 1568 | }
|
---|
| 1569 |
|
---|
| 1570 | int PNGAPI png_image_begin_read_from_memory(png_imagep image,
|
---|
| 1571 | png_const_voidp memory, size_t size)
|
---|
| 1572 | {
|
---|
| 1573 | if (image != NULL && image->version == PNG_IMAGE_VERSION)
|
---|
| 1574 | {
|
---|
| 1575 | if (memory != NULL && size > 0)
|
---|
| 1576 | {
|
---|
| 1577 | if (png_image_read_init(image) != 0)
|
---|
| 1578 | {
|
---|
| 1579 | /* Now set the IO functions to read from the memory buffer and
|
---|
| 1580 | * store it into io_ptr. Again do this in-place to avoid calling a
|
---|
| 1581 | * libpng function that requires error handling.
|
---|
| 1582 | */
|
---|
| 1583 | image->opaque->memory = png_voidcast(png_const_bytep, memory);
|
---|
| 1584 | image->opaque->size = size;
|
---|
| 1585 | image->opaque->png_ptr->io_ptr = image;
|
---|
| 1586 | image->opaque->png_ptr->read_data_fn = png_image_memory_read;
|
---|
| 1587 |
|
---|
| 1588 | return png_safe_execute(image, png_image_read_header, image);
|
---|
| 1589 | }
|
---|
| 1590 | }
|
---|
| 1591 |
|
---|
| 1592 | else
|
---|
| 1593 | return png_image_error(image,
|
---|
| 1594 | "png_image_begin_read_from_memory: invalid argument");
|
---|
| 1595 | }
|
---|
| 1596 |
|
---|
| 1597 | else if (image != NULL)
|
---|
| 1598 | return png_image_error(image,
|
---|
| 1599 | "png_image_begin_read_from_memory: incorrect PNG_IMAGE_VERSION");
|
---|
| 1600 |
|
---|
| 1601 | return 0;
|
---|
| 1602 | }
|
---|
| 1603 |
|
---|
| 1604 | /* Utility function to skip chunks that are not used by the simplified image
|
---|
| 1605 | * read functions and an appropriate macro to call it.
|
---|
| 1606 | */
|
---|
| 1607 | #ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
|
---|
| 1608 | static void
|
---|
| 1609 | png_image_skip_unused_chunks(png_structrp png_ptr)
|
---|
| 1610 | {
|
---|
| 1611 | /* Prepare the reader to ignore all recognized chunks whose data will not
|
---|
| 1612 | * be used, i.e., all chunks recognized by libpng except for those
|
---|
| 1613 | * involved in basic image reading:
|
---|
| 1614 | *
|
---|
| 1615 | * IHDR, PLTE, IDAT, IEND
|
---|
| 1616 | *
|
---|
| 1617 | * Or image data handling:
|
---|
| 1618 | *
|
---|
| 1619 | * tRNS, bKGD, gAMA, cHRM, sRGB, [iCCP] and sBIT.
|
---|
| 1620 | *
|
---|
| 1621 | * This provides a small performance improvement and eliminates any
|
---|
| 1622 | * potential vulnerability to security problems in the unused chunks.
|
---|
| 1623 | *
|
---|
| 1624 | * At present the iCCP chunk data isn't used, so iCCP chunk can be ignored
|
---|
| 1625 | * too. This allows the simplified API to be compiled without iCCP support,
|
---|
| 1626 | * however if the support is there the chunk is still checked to detect
|
---|
| 1627 | * errors (which are unfortunately quite common.)
|
---|
| 1628 | */
|
---|
| 1629 | {
|
---|
| 1630 | static const png_byte chunks_to_process[] = {
|
---|
| 1631 | 98, 75, 71, 68, '\0', /* bKGD */
|
---|
| 1632 | 99, 72, 82, 77, '\0', /* cHRM */
|
---|
| 1633 | 103, 65, 77, 65, '\0', /* gAMA */
|
---|
| 1634 | # ifdef PNG_READ_iCCP_SUPPORTED
|
---|
| 1635 | 105, 67, 67, 80, '\0', /* iCCP */
|
---|
| 1636 | # endif
|
---|
| 1637 | 115, 66, 73, 84, '\0', /* sBIT */
|
---|
| 1638 | 115, 82, 71, 66, '\0', /* sRGB */
|
---|
| 1639 | };
|
---|
| 1640 |
|
---|
| 1641 | /* Ignore unknown chunks and all other chunks except for the
|
---|
| 1642 | * IHDR, PLTE, tRNS, IDAT, and IEND chunks.
|
---|
| 1643 | */
|
---|
| 1644 | png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_NEVER,
|
---|
| 1645 | NULL, -1);
|
---|
| 1646 |
|
---|
| 1647 | /* But do not ignore image data handling chunks */
|
---|
| 1648 | png_set_keep_unknown_chunks(png_ptr, PNG_HANDLE_CHUNK_AS_DEFAULT,
|
---|
| 1649 | chunks_to_process, (int)/*SAFE*/(sizeof chunks_to_process)/5);
|
---|
| 1650 | }
|
---|
| 1651 | }
|
---|
| 1652 |
|
---|
| 1653 | # define PNG_SKIP_CHUNKS(p) png_image_skip_unused_chunks(p)
|
---|
| 1654 | #else
|
---|
| 1655 | # define PNG_SKIP_CHUNKS(p) ((void)0)
|
---|
| 1656 | #endif /* HANDLE_AS_UNKNOWN */
|
---|
| 1657 |
|
---|
| 1658 | /* The following macro gives the exact rounded answer for all values in the
|
---|
| 1659 | * range 0..255 (it actually divides by 51.2, but the rounding still generates
|
---|
| 1660 | * the correct numbers 0..5
|
---|
| 1661 | */
|
---|
| 1662 | #define PNG_DIV51(v8) (((v8) * 5 + 130) >> 8)
|
---|
| 1663 |
|
---|
| 1664 | /* Utility functions to make particular color-maps */
|
---|
| 1665 | static void
|
---|
| 1666 | set_file_encoding(png_image_read_control *display)
|
---|
| 1667 | {
|
---|
| 1668 | png_fixed_point g = display->image->opaque->png_ptr->colorspace.gamma;
|
---|
| 1669 | if (png_gamma_significant(g) != 0)
|
---|
| 1670 | {
|
---|
| 1671 | if (png_gamma_not_sRGB(g) != 0)
|
---|
| 1672 | {
|
---|
| 1673 | display->file_encoding = P_FILE;
|
---|
| 1674 | display->gamma_to_linear = png_reciprocal(g);
|
---|
| 1675 | }
|
---|
| 1676 |
|
---|
| 1677 | else
|
---|
| 1678 | display->file_encoding = P_sRGB;
|
---|
| 1679 | }
|
---|
| 1680 |
|
---|
| 1681 | else
|
---|
| 1682 | display->file_encoding = P_LINEAR8;
|
---|
| 1683 | }
|
---|
| 1684 |
|
---|
| 1685 | static unsigned int
|
---|
| 1686 | decode_gamma(png_image_read_control *display, png_uint_32 value, int encoding)
|
---|
| 1687 | {
|
---|
| 1688 | if (encoding == P_FILE) /* double check */
|
---|
| 1689 | encoding = display->file_encoding;
|
---|
| 1690 |
|
---|
| 1691 | if (encoding == P_NOTSET) /* must be the file encoding */
|
---|
| 1692 | {
|
---|
| 1693 | set_file_encoding(display);
|
---|
| 1694 | encoding = display->file_encoding;
|
---|
| 1695 | }
|
---|
| 1696 |
|
---|
| 1697 | switch (encoding)
|
---|
| 1698 | {
|
---|
| 1699 | case P_FILE:
|
---|
| 1700 | value = png_gamma_16bit_correct(value*257, display->gamma_to_linear);
|
---|
| 1701 | break;
|
---|
| 1702 |
|
---|
| 1703 | case P_sRGB:
|
---|
| 1704 | value = png_sRGB_table[value];
|
---|
| 1705 | break;
|
---|
| 1706 |
|
---|
| 1707 | case P_LINEAR:
|
---|
| 1708 | break;
|
---|
| 1709 |
|
---|
| 1710 | case P_LINEAR8:
|
---|
| 1711 | value *= 257;
|
---|
| 1712 | break;
|
---|
| 1713 |
|
---|
| 1714 | #ifdef __GNUC__
|
---|
| 1715 | default:
|
---|
| 1716 | png_error(display->image->opaque->png_ptr,
|
---|
| 1717 | "unexpected encoding (internal error)");
|
---|
| 1718 | #endif
|
---|
| 1719 | }
|
---|
| 1720 |
|
---|
| 1721 | return value;
|
---|
| 1722 | }
|
---|
| 1723 |
|
---|
| 1724 | static png_uint_32
|
---|
| 1725 | png_colormap_compose(png_image_read_control *display,
|
---|
| 1726 | png_uint_32 foreground, int foreground_encoding, png_uint_32 alpha,
|
---|
| 1727 | png_uint_32 background, int encoding)
|
---|
| 1728 | {
|
---|
| 1729 | /* The file value is composed on the background, the background has the given
|
---|
| 1730 | * encoding and so does the result, the file is encoded with P_FILE and the
|
---|
| 1731 | * file and alpha are 8-bit values. The (output) encoding will always be
|
---|
| 1732 | * P_LINEAR or P_sRGB.
|
---|
| 1733 | */
|
---|
| 1734 | png_uint_32 f = decode_gamma(display, foreground, foreground_encoding);
|
---|
| 1735 | png_uint_32 b = decode_gamma(display, background, encoding);
|
---|
| 1736 |
|
---|
| 1737 | /* The alpha is always an 8-bit value (it comes from the palette), the value
|
---|
| 1738 | * scaled by 255 is what PNG_sRGB_FROM_LINEAR requires.
|
---|
| 1739 | */
|
---|
| 1740 | f = f * alpha + b * (255-alpha);
|
---|
| 1741 |
|
---|
| 1742 | if (encoding == P_LINEAR)
|
---|
| 1743 | {
|
---|
| 1744 | /* Scale to 65535; divide by 255, approximately (in fact this is extremely
|
---|
| 1745 | * accurate, it divides by 255.00000005937181414556, with no overflow.)
|
---|
| 1746 | */
|
---|
| 1747 | f *= 257; /* Now scaled by 65535 */
|
---|
| 1748 | f += f >> 16;
|
---|
| 1749 | f = (f+32768) >> 16;
|
---|
| 1750 | }
|
---|
| 1751 |
|
---|
| 1752 | else /* P_sRGB */
|
---|
| 1753 | f = PNG_sRGB_FROM_LINEAR(f);
|
---|
| 1754 |
|
---|
| 1755 | return f;
|
---|
| 1756 | }
|
---|
| 1757 |
|
---|
| 1758 | /* NOTE: P_LINEAR values to this routine must be 16-bit, but P_FILE values must
|
---|
| 1759 | * be 8-bit.
|
---|
| 1760 | */
|
---|
| 1761 | static void
|
---|
| 1762 | png_create_colormap_entry(png_image_read_control *display,
|
---|
| 1763 | png_uint_32 ip, png_uint_32 red, png_uint_32 green, png_uint_32 blue,
|
---|
| 1764 | png_uint_32 alpha, int encoding)
|
---|
| 1765 | {
|
---|
| 1766 | png_imagep image = display->image;
|
---|
| 1767 | int output_encoding = (image->format & PNG_FORMAT_FLAG_LINEAR) != 0 ?
|
---|
| 1768 | P_LINEAR : P_sRGB;
|
---|
| 1769 | int convert_to_Y = (image->format & PNG_FORMAT_FLAG_COLOR) == 0 &&
|
---|
| 1770 | (red != green || green != blue);
|
---|
| 1771 |
|
---|
| 1772 | if (ip > 255)
|
---|
| 1773 | png_error(image->opaque->png_ptr, "color-map index out of range");
|
---|
| 1774 |
|
---|
| 1775 | /* Update the cache with whether the file gamma is significantly different
|
---|
| 1776 | * from sRGB.
|
---|
| 1777 | */
|
---|
| 1778 | if (encoding == P_FILE)
|
---|
| 1779 | {
|
---|
| 1780 | if (display->file_encoding == P_NOTSET)
|
---|
| 1781 | set_file_encoding(display);
|
---|
| 1782 |
|
---|
| 1783 | /* Note that the cached value may be P_FILE too, but if it is then the
|
---|
| 1784 | * gamma_to_linear member has been set.
|
---|
| 1785 | */
|
---|
| 1786 | encoding = display->file_encoding;
|
---|
| 1787 | }
|
---|
| 1788 |
|
---|
| 1789 | if (encoding == P_FILE)
|
---|
| 1790 | {
|
---|
| 1791 | png_fixed_point g = display->gamma_to_linear;
|
---|
| 1792 |
|
---|
| 1793 | red = png_gamma_16bit_correct(red*257, g);
|
---|
| 1794 | green = png_gamma_16bit_correct(green*257, g);
|
---|
| 1795 | blue = png_gamma_16bit_correct(blue*257, g);
|
---|
| 1796 |
|
---|
| 1797 | if (convert_to_Y != 0 || output_encoding == P_LINEAR)
|
---|
| 1798 | {
|
---|
| 1799 | alpha *= 257;
|
---|
| 1800 | encoding = P_LINEAR;
|
---|
| 1801 | }
|
---|
| 1802 |
|
---|
| 1803 | else
|
---|
| 1804 | {
|
---|
| 1805 | red = PNG_sRGB_FROM_LINEAR(red * 255);
|
---|
| 1806 | green = PNG_sRGB_FROM_LINEAR(green * 255);
|
---|
| 1807 | blue = PNG_sRGB_FROM_LINEAR(blue * 255);
|
---|
| 1808 | encoding = P_sRGB;
|
---|
| 1809 | }
|
---|
| 1810 | }
|
---|
| 1811 |
|
---|
| 1812 | else if (encoding == P_LINEAR8)
|
---|
| 1813 | {
|
---|
| 1814 | /* This encoding occurs quite frequently in test cases because PngSuite
|
---|
| 1815 | * includes a gAMA 1.0 chunk with most images.
|
---|
| 1816 | */
|
---|
| 1817 | red *= 257;
|
---|
| 1818 | green *= 257;
|
---|
| 1819 | blue *= 257;
|
---|
| 1820 | alpha *= 257;
|
---|
| 1821 | encoding = P_LINEAR;
|
---|
| 1822 | }
|
---|
| 1823 |
|
---|
| 1824 | else if (encoding == P_sRGB &&
|
---|
| 1825 | (convert_to_Y != 0 || output_encoding == P_LINEAR))
|
---|
| 1826 | {
|
---|
| 1827 | /* The values are 8-bit sRGB values, but must be converted to 16-bit
|
---|
| 1828 | * linear.
|
---|
| 1829 | */
|
---|
| 1830 | red = png_sRGB_table[red];
|
---|
| 1831 | green = png_sRGB_table[green];
|
---|
| 1832 | blue = png_sRGB_table[blue];
|
---|
| 1833 | alpha *= 257;
|
---|
| 1834 | encoding = P_LINEAR;
|
---|
| 1835 | }
|
---|
| 1836 |
|
---|
| 1837 | /* This is set if the color isn't gray but the output is. */
|
---|
| 1838 | if (encoding == P_LINEAR)
|
---|
| 1839 | {
|
---|
| 1840 | if (convert_to_Y != 0)
|
---|
| 1841 | {
|
---|
| 1842 | /* NOTE: these values are copied from png_do_rgb_to_gray */
|
---|
| 1843 | png_uint_32 y = (png_uint_32)6968 * red + (png_uint_32)23434 * green +
|
---|
| 1844 | (png_uint_32)2366 * blue;
|
---|
| 1845 |
|
---|
| 1846 | if (output_encoding == P_LINEAR)
|
---|
| 1847 | y = (y + 16384) >> 15;
|
---|
| 1848 |
|
---|
| 1849 | else
|
---|
| 1850 | {
|
---|
| 1851 | /* y is scaled by 32768, we need it scaled by 255: */
|
---|
| 1852 | y = (y + 128) >> 8;
|
---|
| 1853 | y *= 255;
|
---|
| 1854 | y = PNG_sRGB_FROM_LINEAR((y + 64) >> 7);
|
---|
| 1855 | alpha = PNG_DIV257(alpha);
|
---|
| 1856 | encoding = P_sRGB;
|
---|
| 1857 | }
|
---|
| 1858 |
|
---|
| 1859 | blue = red = green = y;
|
---|
| 1860 | }
|
---|
| 1861 |
|
---|
| 1862 | else if (output_encoding == P_sRGB)
|
---|
| 1863 | {
|
---|
| 1864 | red = PNG_sRGB_FROM_LINEAR(red * 255);
|
---|
| 1865 | green = PNG_sRGB_FROM_LINEAR(green * 255);
|
---|
| 1866 | blue = PNG_sRGB_FROM_LINEAR(blue * 255);
|
---|
| 1867 | alpha = PNG_DIV257(alpha);
|
---|
| 1868 | encoding = P_sRGB;
|
---|
| 1869 | }
|
---|
| 1870 | }
|
---|
| 1871 |
|
---|
| 1872 | if (encoding != output_encoding)
|
---|
| 1873 | png_error(image->opaque->png_ptr, "bad encoding (internal error)");
|
---|
| 1874 |
|
---|
| 1875 | /* Store the value. */
|
---|
| 1876 | {
|
---|
| 1877 | # ifdef PNG_FORMAT_AFIRST_SUPPORTED
|
---|
| 1878 | int afirst = (image->format & PNG_FORMAT_FLAG_AFIRST) != 0 &&
|
---|
| 1879 | (image->format & PNG_FORMAT_FLAG_ALPHA) != 0;
|
---|
| 1880 | # else
|
---|
| 1881 | # define afirst 0
|
---|
| 1882 | # endif
|
---|
| 1883 | # ifdef PNG_FORMAT_BGR_SUPPORTED
|
---|
| 1884 | int bgr = (image->format & PNG_FORMAT_FLAG_BGR) != 0 ? 2 : 0;
|
---|
| 1885 | # else
|
---|
| 1886 | # define bgr 0
|
---|
| 1887 | # endif
|
---|
| 1888 |
|
---|
| 1889 | if (output_encoding == P_LINEAR)
|
---|
| 1890 | {
|
---|
| 1891 | png_uint_16p entry = png_voidcast(png_uint_16p, display->colormap);
|
---|
| 1892 |
|
---|
| 1893 | entry += ip * PNG_IMAGE_SAMPLE_CHANNELS(image->format);
|
---|
| 1894 |
|
---|
| 1895 | /* The linear 16-bit values must be pre-multiplied by the alpha channel
|
---|
| 1896 | * value, if less than 65535 (this is, effectively, composite on black
|
---|
| 1897 | * if the alpha channel is removed.)
|
---|
| 1898 | */
|
---|
| 1899 | switch (PNG_IMAGE_SAMPLE_CHANNELS(image->format))
|
---|
| 1900 | {
|
---|
| 1901 | case 4:
|
---|
| 1902 | entry[afirst ? 0 : 3] = (png_uint_16)alpha;
|
---|
| 1903 | /* FALLTHROUGH */
|
---|
| 1904 |
|
---|
| 1905 | case 3:
|
---|
| 1906 | if (alpha < 65535)
|
---|
| 1907 | {
|
---|
| 1908 | if (alpha > 0)
|
---|
| 1909 | {
|
---|
| 1910 | blue = (blue * alpha + 32767U)/65535U;
|
---|
| 1911 | green = (green * alpha + 32767U)/65535U;
|
---|
| 1912 | red = (red * alpha + 32767U)/65535U;
|
---|
| 1913 | }
|
---|
| 1914 |
|
---|
| 1915 | else
|
---|
| 1916 | red = green = blue = 0;
|
---|
| 1917 | }
|
---|
| 1918 | entry[afirst + (2 ^ bgr)] = (png_uint_16)blue;
|
---|
| 1919 | entry[afirst + 1] = (png_uint_16)green;
|
---|
| 1920 | entry[afirst + bgr] = (png_uint_16)red;
|
---|
| 1921 | break;
|
---|
| 1922 |
|
---|
| 1923 | case 2:
|
---|
| 1924 | entry[1 ^ afirst] = (png_uint_16)alpha;
|
---|
| 1925 | /* FALLTHROUGH */
|
---|
| 1926 |
|
---|
| 1927 | case 1:
|
---|
| 1928 | if (alpha < 65535)
|
---|
| 1929 | {
|
---|
| 1930 | if (alpha > 0)
|
---|
| 1931 | green = (green * alpha + 32767U)/65535U;
|
---|
| 1932 |
|
---|
| 1933 | else
|
---|
| 1934 | green = 0;
|
---|
| 1935 | }
|
---|
| 1936 | entry[afirst] = (png_uint_16)green;
|
---|
| 1937 | break;
|
---|
| 1938 |
|
---|
| 1939 | default:
|
---|
| 1940 | break;
|
---|
| 1941 | }
|
---|
| 1942 | }
|
---|
| 1943 |
|
---|
| 1944 | else /* output encoding is P_sRGB */
|
---|
| 1945 | {
|
---|
| 1946 | png_bytep entry = png_voidcast(png_bytep, display->colormap);
|
---|
| 1947 |
|
---|
| 1948 | entry += ip * PNG_IMAGE_SAMPLE_CHANNELS(image->format);
|
---|
| 1949 |
|
---|
| 1950 | switch (PNG_IMAGE_SAMPLE_CHANNELS(image->format))
|
---|
| 1951 | {
|
---|
| 1952 | case 4:
|
---|
| 1953 | entry[afirst ? 0 : 3] = (png_byte)alpha;
|
---|
| 1954 | /* FALLTHROUGH */
|
---|
| 1955 | case 3:
|
---|
| 1956 | entry[afirst + (2 ^ bgr)] = (png_byte)blue;
|
---|
| 1957 | entry[afirst + 1] = (png_byte)green;
|
---|
| 1958 | entry[afirst + bgr] = (png_byte)red;
|
---|
| 1959 | break;
|
---|
| 1960 |
|
---|
| 1961 | case 2:
|
---|
| 1962 | entry[1 ^ afirst] = (png_byte)alpha;
|
---|
| 1963 | /* FALLTHROUGH */
|
---|
| 1964 | case 1:
|
---|
| 1965 | entry[afirst] = (png_byte)green;
|
---|
| 1966 | break;
|
---|
| 1967 |
|
---|
| 1968 | default:
|
---|
| 1969 | break;
|
---|
| 1970 | }
|
---|
| 1971 | }
|
---|
| 1972 |
|
---|
| 1973 | # ifdef afirst
|
---|
| 1974 | # undef afirst
|
---|
| 1975 | # endif
|
---|
| 1976 | # ifdef bgr
|
---|
| 1977 | # undef bgr
|
---|
| 1978 | # endif
|
---|
| 1979 | }
|
---|
| 1980 | }
|
---|
| 1981 |
|
---|
| 1982 | static int
|
---|
| 1983 | make_gray_file_colormap(png_image_read_control *display)
|
---|
| 1984 | {
|
---|
| 1985 | unsigned int i;
|
---|
| 1986 |
|
---|
| 1987 | for (i=0; i<256; ++i)
|
---|
| 1988 | png_create_colormap_entry(display, i, i, i, i, 255, P_FILE);
|
---|
| 1989 |
|
---|
| 1990 | return (int)i;
|
---|
| 1991 | }
|
---|
| 1992 |
|
---|
| 1993 | static int
|
---|
| 1994 | make_gray_colormap(png_image_read_control *display)
|
---|
| 1995 | {
|
---|
| 1996 | unsigned int i;
|
---|
| 1997 |
|
---|
| 1998 | for (i=0; i<256; ++i)
|
---|
| 1999 | png_create_colormap_entry(display, i, i, i, i, 255, P_sRGB);
|
---|
| 2000 |
|
---|
| 2001 | return (int)i;
|
---|
| 2002 | }
|
---|
| 2003 | #define PNG_GRAY_COLORMAP_ENTRIES 256
|
---|
| 2004 |
|
---|
| 2005 | static int
|
---|
| 2006 | make_ga_colormap(png_image_read_control *display)
|
---|
| 2007 | {
|
---|
| 2008 | unsigned int i, a;
|
---|
| 2009 |
|
---|
| 2010 | /* Alpha is retained, the output will be a color-map with entries
|
---|
| 2011 | * selected by six levels of alpha. One transparent entry, 6 gray
|
---|
| 2012 | * levels for all the intermediate alpha values, leaving 230 entries
|
---|
| 2013 | * for the opaque grays. The color-map entries are the six values
|
---|
| 2014 | * [0..5]*51, the GA processing uses PNG_DIV51(value) to find the
|
---|
| 2015 | * relevant entry.
|
---|
| 2016 | *
|
---|
| 2017 | * if (alpha > 229) // opaque
|
---|
| 2018 | * {
|
---|
| 2019 | * // The 231 entries are selected to make the math below work:
|
---|
| 2020 | * base = 0;
|
---|
| 2021 | * entry = (231 * gray + 128) >> 8;
|
---|
| 2022 | * }
|
---|
| 2023 | * else if (alpha < 26) // transparent
|
---|
| 2024 | * {
|
---|
| 2025 | * base = 231;
|
---|
| 2026 | * entry = 0;
|
---|
| 2027 | * }
|
---|
| 2028 | * else // partially opaque
|
---|
| 2029 | * {
|
---|
| 2030 | * base = 226 + 6 * PNG_DIV51(alpha);
|
---|
| 2031 | * entry = PNG_DIV51(gray);
|
---|
| 2032 | * }
|
---|
| 2033 | */
|
---|
| 2034 | i = 0;
|
---|
| 2035 | while (i < 231)
|
---|
| 2036 | {
|
---|
| 2037 | unsigned int gray = (i * 256 + 115) / 231;
|
---|
| 2038 | png_create_colormap_entry(display, i++, gray, gray, gray, 255, P_sRGB);
|
---|
| 2039 | }
|
---|
| 2040 |
|
---|
| 2041 | /* 255 is used here for the component values for consistency with the code
|
---|
| 2042 | * that undoes premultiplication in pngwrite.c.
|
---|
| 2043 | */
|
---|
| 2044 | png_create_colormap_entry(display, i++, 255, 255, 255, 0, P_sRGB);
|
---|
| 2045 |
|
---|
| 2046 | for (a=1; a<5; ++a)
|
---|
| 2047 | {
|
---|
| 2048 | unsigned int g;
|
---|
| 2049 |
|
---|
| 2050 | for (g=0; g<6; ++g)
|
---|
| 2051 | png_create_colormap_entry(display, i++, g*51, g*51, g*51, a*51,
|
---|
| 2052 | P_sRGB);
|
---|
| 2053 | }
|
---|
| 2054 |
|
---|
| 2055 | return (int)i;
|
---|
| 2056 | }
|
---|
| 2057 |
|
---|
| 2058 | #define PNG_GA_COLORMAP_ENTRIES 256
|
---|
| 2059 |
|
---|
| 2060 | static int
|
---|
| 2061 | make_rgb_colormap(png_image_read_control *display)
|
---|
| 2062 | {
|
---|
| 2063 | unsigned int i, r;
|
---|
| 2064 |
|
---|
| 2065 | /* Build a 6x6x6 opaque RGB cube */
|
---|
| 2066 | for (i=r=0; r<6; ++r)
|
---|
| 2067 | {
|
---|
| 2068 | unsigned int g;
|
---|
| 2069 |
|
---|
| 2070 | for (g=0; g<6; ++g)
|
---|
| 2071 | {
|
---|
| 2072 | unsigned int b;
|
---|
| 2073 |
|
---|
| 2074 | for (b=0; b<6; ++b)
|
---|
| 2075 | png_create_colormap_entry(display, i++, r*51, g*51, b*51, 255,
|
---|
| 2076 | P_sRGB);
|
---|
| 2077 | }
|
---|
| 2078 | }
|
---|
| 2079 |
|
---|
| 2080 | return (int)i;
|
---|
| 2081 | }
|
---|
| 2082 |
|
---|
| 2083 | #define PNG_RGB_COLORMAP_ENTRIES 216
|
---|
| 2084 |
|
---|
| 2085 | /* Return a palette index to the above palette given three 8-bit sRGB values. */
|
---|
| 2086 | #define PNG_RGB_INDEX(r,g,b) \
|
---|
| 2087 | ((png_byte)(6 * (6 * PNG_DIV51(r) + PNG_DIV51(g)) + PNG_DIV51(b)))
|
---|
| 2088 |
|
---|
| 2089 | static int
|
---|
| 2090 | png_image_read_colormap(png_voidp argument)
|
---|
| 2091 | {
|
---|
| 2092 | png_image_read_control *display =
|
---|
| 2093 | png_voidcast(png_image_read_control*, argument);
|
---|
| 2094 | png_imagep image = display->image;
|
---|
| 2095 |
|
---|
| 2096 | png_structrp png_ptr = image->opaque->png_ptr;
|
---|
| 2097 | png_uint_32 output_format = image->format;
|
---|
| 2098 | int output_encoding = (output_format & PNG_FORMAT_FLAG_LINEAR) != 0 ?
|
---|
| 2099 | P_LINEAR : P_sRGB;
|
---|
| 2100 |
|
---|
| 2101 | unsigned int cmap_entries;
|
---|
| 2102 | unsigned int output_processing; /* Output processing option */
|
---|
| 2103 | unsigned int data_encoding = P_NOTSET; /* Encoding libpng must produce */
|
---|
| 2104 |
|
---|
| 2105 | /* Background information; the background color and the index of this color
|
---|
| 2106 | * in the color-map if it exists (else 256).
|
---|
| 2107 | */
|
---|
| 2108 | unsigned int background_index = 256;
|
---|
| 2109 | png_uint_32 back_r, back_g, back_b;
|
---|
| 2110 |
|
---|
| 2111 | /* Flags to accumulate things that need to be done to the input. */
|
---|
| 2112 | int expand_tRNS = 0;
|
---|
| 2113 |
|
---|
| 2114 | /* Exclude the NYI feature of compositing onto a color-mapped buffer; it is
|
---|
| 2115 | * very difficult to do, the results look awful, and it is difficult to see
|
---|
| 2116 | * what possible use it is because the application can't control the
|
---|
| 2117 | * color-map.
|
---|
| 2118 | */
|
---|
| 2119 | if (((png_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0 ||
|
---|
| 2120 | png_ptr->num_trans > 0) /* alpha in input */ &&
|
---|
| 2121 | ((output_format & PNG_FORMAT_FLAG_ALPHA) == 0) /* no alpha in output */)
|
---|
| 2122 | {
|
---|
| 2123 | if (output_encoding == P_LINEAR) /* compose on black */
|
---|
| 2124 | back_b = back_g = back_r = 0;
|
---|
| 2125 |
|
---|
| 2126 | else if (display->background == NULL /* no way to remove it */)
|
---|
| 2127 | png_error(png_ptr,
|
---|
| 2128 | "background color must be supplied to remove alpha/transparency");
|
---|
| 2129 |
|
---|
| 2130 | /* Get a copy of the background color (this avoids repeating the checks
|
---|
| 2131 | * below.) The encoding is 8-bit sRGB or 16-bit linear, depending on the
|
---|
| 2132 | * output format.
|
---|
| 2133 | */
|
---|
| 2134 | else
|
---|
| 2135 | {
|
---|
| 2136 | back_g = display->background->green;
|
---|
| 2137 | if ((output_format & PNG_FORMAT_FLAG_COLOR) != 0)
|
---|
| 2138 | {
|
---|
| 2139 | back_r = display->background->red;
|
---|
| 2140 | back_b = display->background->blue;
|
---|
| 2141 | }
|
---|
| 2142 | else
|
---|
| 2143 | back_b = back_r = back_g;
|
---|
| 2144 | }
|
---|
| 2145 | }
|
---|
| 2146 |
|
---|
| 2147 | else if (output_encoding == P_LINEAR)
|
---|
| 2148 | back_b = back_r = back_g = 65535;
|
---|
| 2149 |
|
---|
| 2150 | else
|
---|
| 2151 | back_b = back_r = back_g = 255;
|
---|
| 2152 |
|
---|
| 2153 | /* Default the input file gamma if required - this is necessary because
|
---|
| 2154 | * libpng assumes that if no gamma information is present the data is in the
|
---|
| 2155 | * output format, but the simplified API deduces the gamma from the input
|
---|
| 2156 | * format.
|
---|
| 2157 | */
|
---|
| 2158 | if ((png_ptr->colorspace.flags & PNG_COLORSPACE_HAVE_GAMMA) == 0)
|
---|
| 2159 | {
|
---|
| 2160 | /* Do this directly, not using the png_colorspace functions, to ensure
|
---|
| 2161 | * that it happens even if the colorspace is invalid (though probably if
|
---|
| 2162 | * it is the setting will be ignored) Note that the same thing can be
|
---|
| 2163 | * achieved at the application interface with png_set_gAMA.
|
---|
| 2164 | */
|
---|
| 2165 | if (png_ptr->bit_depth == 16 &&
|
---|
| 2166 | (image->flags & PNG_IMAGE_FLAG_16BIT_sRGB) == 0)
|
---|
| 2167 | png_ptr->colorspace.gamma = PNG_GAMMA_LINEAR;
|
---|
| 2168 |
|
---|
| 2169 | else
|
---|
| 2170 | png_ptr->colorspace.gamma = PNG_GAMMA_sRGB_INVERSE;
|
---|
| 2171 |
|
---|
| 2172 | png_ptr->colorspace.flags |= PNG_COLORSPACE_HAVE_GAMMA;
|
---|
| 2173 | }
|
---|
| 2174 |
|
---|
| 2175 | /* Decide what to do based on the PNG color type of the input data. The
|
---|
| 2176 | * utility function png_create_colormap_entry deals with most aspects of the
|
---|
| 2177 | * output transformations; this code works out how to produce bytes of
|
---|
| 2178 | * color-map entries from the original format.
|
---|
| 2179 | */
|
---|
| 2180 | switch (png_ptr->color_type)
|
---|
| 2181 | {
|
---|
| 2182 | case PNG_COLOR_TYPE_GRAY:
|
---|
| 2183 | if (png_ptr->bit_depth <= 8)
|
---|
| 2184 | {
|
---|
| 2185 | /* There at most 256 colors in the output, regardless of
|
---|
| 2186 | * transparency.
|
---|
| 2187 | */
|
---|
| 2188 | unsigned int step, i, val, trans = 256/*ignore*/, back_alpha = 0;
|
---|
| 2189 |
|
---|
| 2190 | cmap_entries = 1U << png_ptr->bit_depth;
|
---|
| 2191 | if (cmap_entries > image->colormap_entries)
|
---|
| 2192 | png_error(png_ptr, "gray[8] color-map: too few entries");
|
---|
| 2193 |
|
---|
| 2194 | step = 255 / (cmap_entries - 1);
|
---|
| 2195 | output_processing = PNG_CMAP_NONE;
|
---|
| 2196 |
|
---|
| 2197 | /* If there is a tRNS chunk then this either selects a transparent
|
---|
| 2198 | * value or, if the output has no alpha, the background color.
|
---|
| 2199 | */
|
---|
| 2200 | if (png_ptr->num_trans > 0)
|
---|
| 2201 | {
|
---|
| 2202 | trans = png_ptr->trans_color.gray;
|
---|
| 2203 |
|
---|
| 2204 | if ((output_format & PNG_FORMAT_FLAG_ALPHA) == 0)
|
---|
| 2205 | back_alpha = output_encoding == P_LINEAR ? 65535 : 255;
|
---|
| 2206 | }
|
---|
| 2207 |
|
---|
| 2208 | /* png_create_colormap_entry just takes an RGBA and writes the
|
---|
| 2209 | * corresponding color-map entry using the format from 'image',
|
---|
| 2210 | * including the required conversion to sRGB or linear as
|
---|
| 2211 | * appropriate. The input values are always either sRGB (if the
|
---|
| 2212 | * gamma correction flag is 0) or 0..255 scaled file encoded values
|
---|
| 2213 | * (if the function must gamma correct them).
|
---|
| 2214 | */
|
---|
| 2215 | for (i=val=0; i<cmap_entries; ++i, val += step)
|
---|
| 2216 | {
|
---|
| 2217 | /* 'i' is a file value. While this will result in duplicated
|
---|
| 2218 | * entries for 8-bit non-sRGB encoded files it is necessary to
|
---|
| 2219 | * have non-gamma corrected values to do tRNS handling.
|
---|
| 2220 | */
|
---|
| 2221 | if (i != trans)
|
---|
| 2222 | png_create_colormap_entry(display, i, val, val, val, 255,
|
---|
| 2223 | P_FILE/*8-bit with file gamma*/);
|
---|
| 2224 |
|
---|
| 2225 | /* Else this entry is transparent. The colors don't matter if
|
---|
| 2226 | * there is an alpha channel (back_alpha == 0), but it does no
|
---|
| 2227 | * harm to pass them in; the values are not set above so this
|
---|
| 2228 | * passes in white.
|
---|
| 2229 | *
|
---|
| 2230 | * NOTE: this preserves the full precision of the application
|
---|
| 2231 | * supplied background color when it is used.
|
---|
| 2232 | */
|
---|
| 2233 | else
|
---|
| 2234 | png_create_colormap_entry(display, i, back_r, back_g, back_b,
|
---|
| 2235 | back_alpha, output_encoding);
|
---|
| 2236 | }
|
---|
| 2237 |
|
---|
| 2238 | /* We need libpng to preserve the original encoding. */
|
---|
| 2239 | data_encoding = P_FILE;
|
---|
| 2240 |
|
---|
| 2241 | /* The rows from libpng, while technically gray values, are now also
|
---|
| 2242 | * color-map indices; however, they may need to be expanded to 1
|
---|
| 2243 | * byte per pixel. This is what png_set_packing does (i.e., it
|
---|
| 2244 | * unpacks the bit values into bytes.)
|
---|
| 2245 | */
|
---|
| 2246 | if (png_ptr->bit_depth < 8)
|
---|
| 2247 | png_set_packing(png_ptr);
|
---|
| 2248 | }
|
---|
| 2249 |
|
---|
| 2250 | else /* bit depth is 16 */
|
---|
| 2251 | {
|
---|
| 2252 | /* The 16-bit input values can be converted directly to 8-bit gamma
|
---|
| 2253 | * encoded values; however, if a tRNS chunk is present 257 color-map
|
---|
| 2254 | * entries are required. This means that the extra entry requires
|
---|
| 2255 | * special processing; add an alpha channel, sacrifice gray level
|
---|
| 2256 | * 254 and convert transparent (alpha==0) entries to that.
|
---|
| 2257 | *
|
---|
| 2258 | * Use libpng to chop the data to 8 bits. Convert it to sRGB at the
|
---|
| 2259 | * same time to minimize quality loss. If a tRNS chunk is present
|
---|
| 2260 | * this means libpng must handle it too; otherwise it is impossible
|
---|
| 2261 | * to do the exact match on the 16-bit value.
|
---|
| 2262 | *
|
---|
| 2263 | * If the output has no alpha channel *and* the background color is
|
---|
| 2264 | * gray then it is possible to let libpng handle the substitution by
|
---|
| 2265 | * ensuring that the corresponding gray level matches the background
|
---|
| 2266 | * color exactly.
|
---|
| 2267 | */
|
---|
| 2268 | data_encoding = P_sRGB;
|
---|
| 2269 |
|
---|
| 2270 | if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries)
|
---|
| 2271 | png_error(png_ptr, "gray[16] color-map: too few entries");
|
---|
| 2272 |
|
---|
| 2273 | cmap_entries = (unsigned int)make_gray_colormap(display);
|
---|
| 2274 |
|
---|
| 2275 | if (png_ptr->num_trans > 0)
|
---|
| 2276 | {
|
---|
| 2277 | unsigned int back_alpha;
|
---|
| 2278 |
|
---|
| 2279 | if ((output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
|
---|
| 2280 | back_alpha = 0;
|
---|
| 2281 |
|
---|
| 2282 | else
|
---|
| 2283 | {
|
---|
| 2284 | if (back_r == back_g && back_g == back_b)
|
---|
| 2285 | {
|
---|
| 2286 | /* Background is gray; no special processing will be
|
---|
| 2287 | * required.
|
---|
| 2288 | */
|
---|
| 2289 | png_color_16 c;
|
---|
| 2290 | png_uint_32 gray = back_g;
|
---|
| 2291 |
|
---|
| 2292 | if (output_encoding == P_LINEAR)
|
---|
| 2293 | {
|
---|
| 2294 | gray = PNG_sRGB_FROM_LINEAR(gray * 255);
|
---|
| 2295 |
|
---|
| 2296 | /* And make sure the corresponding palette entry
|
---|
| 2297 | * matches.
|
---|
| 2298 | */
|
---|
| 2299 | png_create_colormap_entry(display, gray, back_g, back_g,
|
---|
| 2300 | back_g, 65535, P_LINEAR);
|
---|
| 2301 | }
|
---|
| 2302 |
|
---|
| 2303 | /* The background passed to libpng, however, must be the
|
---|
| 2304 | * sRGB value.
|
---|
| 2305 | */
|
---|
| 2306 | c.index = 0; /*unused*/
|
---|
| 2307 | c.gray = c.red = c.green = c.blue = (png_uint_16)gray;
|
---|
| 2308 |
|
---|
| 2309 | /* NOTE: does this work without expanding tRNS to alpha?
|
---|
| 2310 | * It should be the color->gray case below apparently
|
---|
| 2311 | * doesn't.
|
---|
| 2312 | */
|
---|
| 2313 | png_set_background_fixed(png_ptr, &c,
|
---|
| 2314 | PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
|
---|
| 2315 | 0/*gamma: not used*/);
|
---|
| 2316 |
|
---|
| 2317 | output_processing = PNG_CMAP_NONE;
|
---|
| 2318 | break;
|
---|
| 2319 | }
|
---|
| 2320 | #ifdef __COVERITY__
|
---|
| 2321 | /* Coverity claims that output_encoding cannot be 2 (P_LINEAR)
|
---|
| 2322 | * here.
|
---|
| 2323 | */
|
---|
| 2324 | back_alpha = 255;
|
---|
| 2325 | #else
|
---|
| 2326 | back_alpha = output_encoding == P_LINEAR ? 65535 : 255;
|
---|
| 2327 | #endif
|
---|
| 2328 | }
|
---|
| 2329 |
|
---|
| 2330 | /* output_processing means that the libpng-processed row will be
|
---|
| 2331 | * 8-bit GA and it has to be processing to single byte color-map
|
---|
| 2332 | * values. Entry 254 is replaced by either a completely
|
---|
| 2333 | * transparent entry or by the background color at full
|
---|
| 2334 | * precision (and the background color is not a simple gray
|
---|
| 2335 | * level in this case.)
|
---|
| 2336 | */
|
---|
| 2337 | expand_tRNS = 1;
|
---|
| 2338 | output_processing = PNG_CMAP_TRANS;
|
---|
| 2339 | background_index = 254;
|
---|
| 2340 |
|
---|
| 2341 | /* And set (overwrite) color-map entry 254 to the actual
|
---|
| 2342 | * background color at full precision.
|
---|
| 2343 | */
|
---|
| 2344 | png_create_colormap_entry(display, 254, back_r, back_g, back_b,
|
---|
| 2345 | back_alpha, output_encoding);
|
---|
| 2346 | }
|
---|
| 2347 |
|
---|
| 2348 | else
|
---|
| 2349 | output_processing = PNG_CMAP_NONE;
|
---|
| 2350 | }
|
---|
| 2351 | break;
|
---|
| 2352 |
|
---|
| 2353 | case PNG_COLOR_TYPE_GRAY_ALPHA:
|
---|
| 2354 | /* 8-bit or 16-bit PNG with two channels - gray and alpha. A minimum
|
---|
| 2355 | * of 65536 combinations. If, however, the alpha channel is to be
|
---|
| 2356 | * removed there are only 256 possibilities if the background is gray.
|
---|
| 2357 | * (Otherwise there is a subset of the 65536 possibilities defined by
|
---|
| 2358 | * the triangle between black, white and the background color.)
|
---|
| 2359 | *
|
---|
| 2360 | * Reduce 16-bit files to 8-bit and sRGB encode the result. No need to
|
---|
| 2361 | * worry about tRNS matching - tRNS is ignored if there is an alpha
|
---|
| 2362 | * channel.
|
---|
| 2363 | */
|
---|
| 2364 | data_encoding = P_sRGB;
|
---|
| 2365 |
|
---|
| 2366 | if ((output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
|
---|
| 2367 | {
|
---|
| 2368 | if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries)
|
---|
| 2369 | png_error(png_ptr, "gray+alpha color-map: too few entries");
|
---|
| 2370 |
|
---|
| 2371 | cmap_entries = (unsigned int)make_ga_colormap(display);
|
---|
| 2372 |
|
---|
| 2373 | background_index = PNG_CMAP_GA_BACKGROUND;
|
---|
| 2374 | output_processing = PNG_CMAP_GA;
|
---|
| 2375 | }
|
---|
| 2376 |
|
---|
| 2377 | else /* alpha is removed */
|
---|
| 2378 | {
|
---|
| 2379 | /* Alpha must be removed as the PNG data is processed when the
|
---|
| 2380 | * background is a color because the G and A channels are
|
---|
| 2381 | * independent and the vector addition (non-parallel vectors) is a
|
---|
| 2382 | * 2-D problem.
|
---|
| 2383 | *
|
---|
| 2384 | * This can be reduced to the same algorithm as above by making a
|
---|
| 2385 | * colormap containing gray levels (for the opaque grays), a
|
---|
| 2386 | * background entry (for a transparent pixel) and a set of four six
|
---|
| 2387 | * level color values, one set for each intermediate alpha value.
|
---|
| 2388 | * See the comments in make_ga_colormap for how this works in the
|
---|
| 2389 | * per-pixel processing.
|
---|
| 2390 | *
|
---|
| 2391 | * If the background is gray, however, we only need a 256 entry gray
|
---|
| 2392 | * level color map. It is sufficient to make the entry generated
|
---|
| 2393 | * for the background color be exactly the color specified.
|
---|
| 2394 | */
|
---|
| 2395 | if ((output_format & PNG_FORMAT_FLAG_COLOR) == 0 ||
|
---|
| 2396 | (back_r == back_g && back_g == back_b))
|
---|
| 2397 | {
|
---|
| 2398 | /* Background is gray; no special processing will be required. */
|
---|
| 2399 | png_color_16 c;
|
---|
| 2400 | png_uint_32 gray = back_g;
|
---|
| 2401 |
|
---|
| 2402 | if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries)
|
---|
| 2403 | png_error(png_ptr, "gray-alpha color-map: too few entries");
|
---|
| 2404 |
|
---|
| 2405 | cmap_entries = (unsigned int)make_gray_colormap(display);
|
---|
| 2406 |
|
---|
| 2407 | if (output_encoding == P_LINEAR)
|
---|
| 2408 | {
|
---|
| 2409 | gray = PNG_sRGB_FROM_LINEAR(gray * 255);
|
---|
| 2410 |
|
---|
| 2411 | /* And make sure the corresponding palette entry matches. */
|
---|
| 2412 | png_create_colormap_entry(display, gray, back_g, back_g,
|
---|
| 2413 | back_g, 65535, P_LINEAR);
|
---|
| 2414 | }
|
---|
| 2415 |
|
---|
| 2416 | /* The background passed to libpng, however, must be the sRGB
|
---|
| 2417 | * value.
|
---|
| 2418 | */
|
---|
| 2419 | c.index = 0; /*unused*/
|
---|
| 2420 | c.gray = c.red = c.green = c.blue = (png_uint_16)gray;
|
---|
| 2421 |
|
---|
| 2422 | png_set_background_fixed(png_ptr, &c,
|
---|
| 2423 | PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
|
---|
| 2424 | 0/*gamma: not used*/);
|
---|
| 2425 |
|
---|
| 2426 | output_processing = PNG_CMAP_NONE;
|
---|
| 2427 | }
|
---|
| 2428 |
|
---|
| 2429 | else
|
---|
| 2430 | {
|
---|
| 2431 | png_uint_32 i, a;
|
---|
| 2432 |
|
---|
| 2433 | /* This is the same as png_make_ga_colormap, above, except that
|
---|
| 2434 | * the entries are all opaque.
|
---|
| 2435 | */
|
---|
| 2436 | if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries)
|
---|
| 2437 | png_error(png_ptr, "ga-alpha color-map: too few entries");
|
---|
| 2438 |
|
---|
| 2439 | i = 0;
|
---|
| 2440 | while (i < 231)
|
---|
| 2441 | {
|
---|
| 2442 | png_uint_32 gray = (i * 256 + 115) / 231;
|
---|
| 2443 | png_create_colormap_entry(display, i++, gray, gray, gray,
|
---|
| 2444 | 255, P_sRGB);
|
---|
| 2445 | }
|
---|
| 2446 |
|
---|
| 2447 | /* NOTE: this preserves the full precision of the application
|
---|
| 2448 | * background color.
|
---|
| 2449 | */
|
---|
| 2450 | background_index = i;
|
---|
| 2451 | png_create_colormap_entry(display, i++, back_r, back_g, back_b,
|
---|
| 2452 | #ifdef __COVERITY__
|
---|
| 2453 | /* Coverity claims that output_encoding
|
---|
| 2454 | * cannot be 2 (P_LINEAR) here.
|
---|
| 2455 | */ 255U,
|
---|
| 2456 | #else
|
---|
| 2457 | output_encoding == P_LINEAR ? 65535U : 255U,
|
---|
| 2458 | #endif
|
---|
| 2459 | output_encoding);
|
---|
| 2460 |
|
---|
| 2461 | /* For non-opaque input composite on the sRGB background - this
|
---|
| 2462 | * requires inverting the encoding for each component. The input
|
---|
| 2463 | * is still converted to the sRGB encoding because this is a
|
---|
| 2464 | * reasonable approximate to the logarithmic curve of human
|
---|
| 2465 | * visual sensitivity, at least over the narrow range which PNG
|
---|
| 2466 | * represents. Consequently 'G' is always sRGB encoded, while
|
---|
| 2467 | * 'A' is linear. We need the linear background colors.
|
---|
| 2468 | */
|
---|
| 2469 | if (output_encoding == P_sRGB) /* else already linear */
|
---|
| 2470 | {
|
---|
| 2471 | /* This may produce a value not exactly matching the
|
---|
| 2472 | * background, but that's ok because these numbers are only
|
---|
| 2473 | * used when alpha != 0
|
---|
| 2474 | */
|
---|
| 2475 | back_r = png_sRGB_table[back_r];
|
---|
| 2476 | back_g = png_sRGB_table[back_g];
|
---|
| 2477 | back_b = png_sRGB_table[back_b];
|
---|
| 2478 | }
|
---|
| 2479 |
|
---|
| 2480 | for (a=1; a<5; ++a)
|
---|
| 2481 | {
|
---|
| 2482 | unsigned int g;
|
---|
| 2483 |
|
---|
| 2484 | /* PNG_sRGB_FROM_LINEAR expects a 16-bit linear value scaled
|
---|
| 2485 | * by an 8-bit alpha value (0..255).
|
---|
| 2486 | */
|
---|
| 2487 | png_uint_32 alpha = 51 * a;
|
---|
| 2488 | png_uint_32 back_rx = (255-alpha) * back_r;
|
---|
| 2489 | png_uint_32 back_gx = (255-alpha) * back_g;
|
---|
| 2490 | png_uint_32 back_bx = (255-alpha) * back_b;
|
---|
| 2491 |
|
---|
| 2492 | for (g=0; g<6; ++g)
|
---|
| 2493 | {
|
---|
| 2494 | png_uint_32 gray = png_sRGB_table[g*51] * alpha;
|
---|
| 2495 |
|
---|
| 2496 | png_create_colormap_entry(display, i++,
|
---|
| 2497 | PNG_sRGB_FROM_LINEAR(gray + back_rx),
|
---|
| 2498 | PNG_sRGB_FROM_LINEAR(gray + back_gx),
|
---|
| 2499 | PNG_sRGB_FROM_LINEAR(gray + back_bx), 255, P_sRGB);
|
---|
| 2500 | }
|
---|
| 2501 | }
|
---|
| 2502 |
|
---|
| 2503 | cmap_entries = i;
|
---|
| 2504 | output_processing = PNG_CMAP_GA;
|
---|
| 2505 | }
|
---|
| 2506 | }
|
---|
| 2507 | break;
|
---|
| 2508 |
|
---|
| 2509 | case PNG_COLOR_TYPE_RGB:
|
---|
| 2510 | case PNG_COLOR_TYPE_RGB_ALPHA:
|
---|
| 2511 | /* Exclude the case where the output is gray; we can always handle this
|
---|
| 2512 | * with the cases above.
|
---|
| 2513 | */
|
---|
| 2514 | if ((output_format & PNG_FORMAT_FLAG_COLOR) == 0)
|
---|
| 2515 | {
|
---|
| 2516 | /* The color-map will be grayscale, so we may as well convert the
|
---|
| 2517 | * input RGB values to a simple grayscale and use the grayscale
|
---|
| 2518 | * code above.
|
---|
| 2519 | *
|
---|
| 2520 | * NOTE: calling this apparently damages the recognition of the
|
---|
| 2521 | * transparent color in background color handling; call
|
---|
| 2522 | * png_set_tRNS_to_alpha before png_set_background_fixed.
|
---|
| 2523 | */
|
---|
| 2524 | png_set_rgb_to_gray_fixed(png_ptr, PNG_ERROR_ACTION_NONE, -1,
|
---|
| 2525 | -1);
|
---|
| 2526 | data_encoding = P_sRGB;
|
---|
| 2527 |
|
---|
| 2528 | /* The output will now be one or two 8-bit gray or gray+alpha
|
---|
| 2529 | * channels. The more complex case arises when the input has alpha.
|
---|
| 2530 | */
|
---|
| 2531 | if ((png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
|
---|
| 2532 | png_ptr->num_trans > 0) &&
|
---|
| 2533 | (output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
|
---|
| 2534 | {
|
---|
| 2535 | /* Both input and output have an alpha channel, so no background
|
---|
| 2536 | * processing is required; just map the GA bytes to the right
|
---|
| 2537 | * color-map entry.
|
---|
| 2538 | */
|
---|
| 2539 | expand_tRNS = 1;
|
---|
| 2540 |
|
---|
| 2541 | if (PNG_GA_COLORMAP_ENTRIES > image->colormap_entries)
|
---|
| 2542 | png_error(png_ptr, "rgb[ga] color-map: too few entries");
|
---|
| 2543 |
|
---|
| 2544 | cmap_entries = (unsigned int)make_ga_colormap(display);
|
---|
| 2545 | background_index = PNG_CMAP_GA_BACKGROUND;
|
---|
| 2546 | output_processing = PNG_CMAP_GA;
|
---|
| 2547 | }
|
---|
| 2548 |
|
---|
| 2549 | else
|
---|
| 2550 | {
|
---|
| 2551 | /* Either the input or the output has no alpha channel, so there
|
---|
| 2552 | * will be no non-opaque pixels in the color-map; it will just be
|
---|
| 2553 | * grayscale.
|
---|
| 2554 | */
|
---|
| 2555 | if (PNG_GRAY_COLORMAP_ENTRIES > image->colormap_entries)
|
---|
| 2556 | png_error(png_ptr, "rgb[gray] color-map: too few entries");
|
---|
| 2557 |
|
---|
| 2558 | /* Ideally this code would use libpng to do the gamma correction,
|
---|
| 2559 | * but if an input alpha channel is to be removed we will hit the
|
---|
| 2560 | * libpng bug in gamma+compose+rgb-to-gray (the double gamma
|
---|
| 2561 | * correction bug). Fix this by dropping the gamma correction in
|
---|
| 2562 | * this case and doing it in the palette; this will result in
|
---|
| 2563 | * duplicate palette entries, but that's better than the
|
---|
| 2564 | * alternative of double gamma correction.
|
---|
| 2565 | */
|
---|
| 2566 | if ((png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
|
---|
| 2567 | png_ptr->num_trans > 0) &&
|
---|
| 2568 | png_gamma_not_sRGB(png_ptr->colorspace.gamma) != 0)
|
---|
| 2569 | {
|
---|
| 2570 | cmap_entries = (unsigned int)make_gray_file_colormap(display);
|
---|
| 2571 | data_encoding = P_FILE;
|
---|
| 2572 | }
|
---|
| 2573 |
|
---|
| 2574 | else
|
---|
| 2575 | cmap_entries = (unsigned int)make_gray_colormap(display);
|
---|
| 2576 |
|
---|
| 2577 | /* But if the input has alpha or transparency it must be removed
|
---|
| 2578 | */
|
---|
| 2579 | if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
|
---|
| 2580 | png_ptr->num_trans > 0)
|
---|
| 2581 | {
|
---|
| 2582 | png_color_16 c;
|
---|
| 2583 | png_uint_32 gray = back_g;
|
---|
| 2584 |
|
---|
| 2585 | /* We need to ensure that the application background exists in
|
---|
| 2586 | * the colormap and that completely transparent pixels map to
|
---|
| 2587 | * it. Achieve this simply by ensuring that the entry
|
---|
| 2588 | * selected for the background really is the background color.
|
---|
| 2589 | */
|
---|
| 2590 | if (data_encoding == P_FILE) /* from the fixup above */
|
---|
| 2591 | {
|
---|
| 2592 | /* The app supplied a gray which is in output_encoding, we
|
---|
| 2593 | * need to convert it to a value of the input (P_FILE)
|
---|
| 2594 | * encoding then set this palette entry to the required
|
---|
| 2595 | * output encoding.
|
---|
| 2596 | */
|
---|
| 2597 | if (output_encoding == P_sRGB)
|
---|
| 2598 | gray = png_sRGB_table[gray]; /* now P_LINEAR */
|
---|
| 2599 |
|
---|
| 2600 | gray = PNG_DIV257(png_gamma_16bit_correct(gray,
|
---|
| 2601 | png_ptr->colorspace.gamma)); /* now P_FILE */
|
---|
| 2602 |
|
---|
| 2603 | /* And make sure the corresponding palette entry contains
|
---|
| 2604 | * exactly the required sRGB value.
|
---|
| 2605 | */
|
---|
| 2606 | png_create_colormap_entry(display, gray, back_g, back_g,
|
---|
| 2607 | back_g, 0/*unused*/, output_encoding);
|
---|
| 2608 | }
|
---|
| 2609 |
|
---|
| 2610 | else if (output_encoding == P_LINEAR)
|
---|
| 2611 | {
|
---|
| 2612 | gray = PNG_sRGB_FROM_LINEAR(gray * 255);
|
---|
| 2613 |
|
---|
| 2614 | /* And make sure the corresponding palette entry matches.
|
---|
| 2615 | */
|
---|
| 2616 | png_create_colormap_entry(display, gray, back_g, back_g,
|
---|
| 2617 | back_g, 0/*unused*/, P_LINEAR);
|
---|
| 2618 | }
|
---|
| 2619 |
|
---|
| 2620 | /* The background passed to libpng, however, must be the
|
---|
| 2621 | * output (normally sRGB) value.
|
---|
| 2622 | */
|
---|
| 2623 | c.index = 0; /*unused*/
|
---|
| 2624 | c.gray = c.red = c.green = c.blue = (png_uint_16)gray;
|
---|
| 2625 |
|
---|
| 2626 | /* NOTE: the following is apparently a bug in libpng. Without
|
---|
| 2627 | * it the transparent color recognition in
|
---|
| 2628 | * png_set_background_fixed seems to go wrong.
|
---|
| 2629 | */
|
---|
| 2630 | expand_tRNS = 1;
|
---|
| 2631 | png_set_background_fixed(png_ptr, &c,
|
---|
| 2632 | PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
|
---|
| 2633 | 0/*gamma: not used*/);
|
---|
| 2634 | }
|
---|
| 2635 |
|
---|
| 2636 | output_processing = PNG_CMAP_NONE;
|
---|
| 2637 | }
|
---|
| 2638 | }
|
---|
| 2639 |
|
---|
| 2640 | else /* output is color */
|
---|
| 2641 | {
|
---|
| 2642 | /* We could use png_quantize here so long as there is no transparent
|
---|
| 2643 | * color or alpha; png_quantize ignores alpha. Easier overall just
|
---|
| 2644 | * to do it once and using PNG_DIV51 on the 6x6x6 reduced RGB cube.
|
---|
| 2645 | * Consequently we always want libpng to produce sRGB data.
|
---|
| 2646 | */
|
---|
| 2647 | data_encoding = P_sRGB;
|
---|
| 2648 |
|
---|
| 2649 | /* Is there any transparency or alpha? */
|
---|
| 2650 | if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA ||
|
---|
| 2651 | png_ptr->num_trans > 0)
|
---|
| 2652 | {
|
---|
| 2653 | /* Is there alpha in the output too? If so all four channels are
|
---|
| 2654 | * processed into a special RGB cube with alpha support.
|
---|
| 2655 | */
|
---|
| 2656 | if ((output_format & PNG_FORMAT_FLAG_ALPHA) != 0)
|
---|
| 2657 | {
|
---|
| 2658 | png_uint_32 r;
|
---|
| 2659 |
|
---|
| 2660 | if (PNG_RGB_COLORMAP_ENTRIES+1+27 > image->colormap_entries)
|
---|
| 2661 | png_error(png_ptr, "rgb+alpha color-map: too few entries");
|
---|
| 2662 |
|
---|
| 2663 | cmap_entries = (unsigned int)make_rgb_colormap(display);
|
---|
| 2664 |
|
---|
| 2665 | /* Add a transparent entry. */
|
---|
| 2666 | png_create_colormap_entry(display, cmap_entries, 255, 255,
|
---|
| 2667 | 255, 0, P_sRGB);
|
---|
| 2668 |
|
---|
| 2669 | /* This is stored as the background index for the processing
|
---|
| 2670 | * algorithm.
|
---|
| 2671 | */
|
---|
| 2672 | background_index = cmap_entries++;
|
---|
| 2673 |
|
---|
| 2674 | /* Add 27 r,g,b entries each with alpha 0.5. */
|
---|
| 2675 | for (r=0; r<256; r = (r << 1) | 0x7f)
|
---|
| 2676 | {
|
---|
| 2677 | png_uint_32 g;
|
---|
| 2678 |
|
---|
| 2679 | for (g=0; g<256; g = (g << 1) | 0x7f)
|
---|
| 2680 | {
|
---|
| 2681 | png_uint_32 b;
|
---|
| 2682 |
|
---|
| 2683 | /* This generates components with the values 0, 127 and
|
---|
| 2684 | * 255
|
---|
| 2685 | */
|
---|
| 2686 | for (b=0; b<256; b = (b << 1) | 0x7f)
|
---|
| 2687 | png_create_colormap_entry(display, cmap_entries++,
|
---|
| 2688 | r, g, b, 128, P_sRGB);
|
---|
| 2689 | }
|
---|
| 2690 | }
|
---|
| 2691 |
|
---|
| 2692 | expand_tRNS = 1;
|
---|
| 2693 | output_processing = PNG_CMAP_RGB_ALPHA;
|
---|
| 2694 | }
|
---|
| 2695 |
|
---|
| 2696 | else
|
---|
| 2697 | {
|
---|
| 2698 | /* Alpha/transparency must be removed. The background must
|
---|
| 2699 | * exist in the color map (achieved by setting adding it after
|
---|
| 2700 | * the 666 color-map). If the standard processing code will
|
---|
| 2701 | * pick up this entry automatically that's all that is
|
---|
| 2702 | * required; libpng can be called to do the background
|
---|
| 2703 | * processing.
|
---|
| 2704 | */
|
---|
| 2705 | unsigned int sample_size =
|
---|
| 2706 | PNG_IMAGE_SAMPLE_SIZE(output_format);
|
---|
| 2707 | png_uint_32 r, g, b; /* sRGB background */
|
---|
| 2708 |
|
---|
| 2709 | if (PNG_RGB_COLORMAP_ENTRIES+1+27 > image->colormap_entries)
|
---|
| 2710 | png_error(png_ptr, "rgb-alpha color-map: too few entries");
|
---|
| 2711 |
|
---|
| 2712 | cmap_entries = (unsigned int)make_rgb_colormap(display);
|
---|
| 2713 |
|
---|
| 2714 | png_create_colormap_entry(display, cmap_entries, back_r,
|
---|
| 2715 | back_g, back_b, 0/*unused*/, output_encoding);
|
---|
| 2716 |
|
---|
| 2717 | if (output_encoding == P_LINEAR)
|
---|
| 2718 | {
|
---|
| 2719 | r = PNG_sRGB_FROM_LINEAR(back_r * 255);
|
---|
| 2720 | g = PNG_sRGB_FROM_LINEAR(back_g * 255);
|
---|
| 2721 | b = PNG_sRGB_FROM_LINEAR(back_b * 255);
|
---|
| 2722 | }
|
---|
| 2723 |
|
---|
| 2724 | else
|
---|
| 2725 | {
|
---|
| 2726 | r = back_r;
|
---|
| 2727 | g = back_g;
|
---|
| 2728 | b = back_g;
|
---|
| 2729 | }
|
---|
| 2730 |
|
---|
| 2731 | /* Compare the newly-created color-map entry with the one the
|
---|
| 2732 | * PNG_CMAP_RGB algorithm will use. If the two entries don't
|
---|
| 2733 | * match, add the new one and set this as the background
|
---|
| 2734 | * index.
|
---|
| 2735 | */
|
---|
| 2736 | if (memcmp((png_const_bytep)display->colormap +
|
---|
| 2737 | sample_size * cmap_entries,
|
---|
| 2738 | (png_const_bytep)display->colormap +
|
---|
| 2739 | sample_size * PNG_RGB_INDEX(r,g,b),
|
---|
| 2740 | sample_size) != 0)
|
---|
| 2741 | {
|
---|
| 2742 | /* The background color must be added. */
|
---|
| 2743 | background_index = cmap_entries++;
|
---|
| 2744 |
|
---|
| 2745 | /* Add 27 r,g,b entries each with created by composing with
|
---|
| 2746 | * the background at alpha 0.5.
|
---|
| 2747 | */
|
---|
| 2748 | for (r=0; r<256; r = (r << 1) | 0x7f)
|
---|
| 2749 | {
|
---|
| 2750 | for (g=0; g<256; g = (g << 1) | 0x7f)
|
---|
| 2751 | {
|
---|
| 2752 | /* This generates components with the values 0, 127
|
---|
| 2753 | * and 255
|
---|
| 2754 | */
|
---|
| 2755 | for (b=0; b<256; b = (b << 1) | 0x7f)
|
---|
| 2756 | png_create_colormap_entry(display, cmap_entries++,
|
---|
| 2757 | png_colormap_compose(display, r, P_sRGB, 128,
|
---|
| 2758 | back_r, output_encoding),
|
---|
| 2759 | png_colormap_compose(display, g, P_sRGB, 128,
|
---|
| 2760 | back_g, output_encoding),
|
---|
| 2761 | png_colormap_compose(display, b, P_sRGB, 128,
|
---|
| 2762 | back_b, output_encoding),
|
---|
| 2763 | 0/*unused*/, output_encoding);
|
---|
| 2764 | }
|
---|
| 2765 | }
|
---|
| 2766 |
|
---|
| 2767 | expand_tRNS = 1;
|
---|
| 2768 | output_processing = PNG_CMAP_RGB_ALPHA;
|
---|
| 2769 | }
|
---|
| 2770 |
|
---|
| 2771 | else /* background color is in the standard color-map */
|
---|
| 2772 | {
|
---|
| 2773 | png_color_16 c;
|
---|
| 2774 |
|
---|
| 2775 | c.index = 0; /*unused*/
|
---|
| 2776 | c.red = (png_uint_16)back_r;
|
---|
| 2777 | c.gray = c.green = (png_uint_16)back_g;
|
---|
| 2778 | c.blue = (png_uint_16)back_b;
|
---|
| 2779 |
|
---|
| 2780 | png_set_background_fixed(png_ptr, &c,
|
---|
| 2781 | PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
|
---|
| 2782 | 0/*gamma: not used*/);
|
---|
| 2783 |
|
---|
| 2784 | output_processing = PNG_CMAP_RGB;
|
---|
| 2785 | }
|
---|
| 2786 | }
|
---|
| 2787 | }
|
---|
| 2788 |
|
---|
| 2789 | else /* no alpha or transparency in the input */
|
---|
| 2790 | {
|
---|
| 2791 | /* Alpha in the output is irrelevant, simply map the opaque input
|
---|
| 2792 | * pixels to the 6x6x6 color-map.
|
---|
| 2793 | */
|
---|
| 2794 | if (PNG_RGB_COLORMAP_ENTRIES > image->colormap_entries)
|
---|
| 2795 | png_error(png_ptr, "rgb color-map: too few entries");
|
---|
| 2796 |
|
---|
| 2797 | cmap_entries = (unsigned int)make_rgb_colormap(display);
|
---|
| 2798 | output_processing = PNG_CMAP_RGB;
|
---|
| 2799 | }
|
---|
| 2800 | }
|
---|
| 2801 | break;
|
---|
| 2802 |
|
---|
| 2803 | case PNG_COLOR_TYPE_PALETTE:
|
---|
| 2804 | /* It's already got a color-map. It may be necessary to eliminate the
|
---|
| 2805 | * tRNS entries though.
|
---|
| 2806 | */
|
---|
| 2807 | {
|
---|
| 2808 | unsigned int num_trans = png_ptr->num_trans;
|
---|
| 2809 | png_const_bytep trans = num_trans > 0 ? png_ptr->trans_alpha : NULL;
|
---|
| 2810 | png_const_colorp colormap = png_ptr->palette;
|
---|
| 2811 | int do_background = trans != NULL &&
|
---|
| 2812 | (output_format & PNG_FORMAT_FLAG_ALPHA) == 0;
|
---|
| 2813 | unsigned int i;
|
---|
| 2814 |
|
---|
| 2815 | /* Just in case: */
|
---|
| 2816 | if (trans == NULL)
|
---|
| 2817 | num_trans = 0;
|
---|
| 2818 |
|
---|
| 2819 | output_processing = PNG_CMAP_NONE;
|
---|
| 2820 | data_encoding = P_FILE; /* Don't change from color-map indices */
|
---|
| 2821 | cmap_entries = (unsigned int)png_ptr->num_palette;
|
---|
| 2822 | if (cmap_entries > 256)
|
---|
| 2823 | cmap_entries = 256;
|
---|
| 2824 |
|
---|
| 2825 | if (cmap_entries > (unsigned int)image->colormap_entries)
|
---|
| 2826 | png_error(png_ptr, "palette color-map: too few entries");
|
---|
| 2827 |
|
---|
| 2828 | for (i=0; i < cmap_entries; ++i)
|
---|
| 2829 | {
|
---|
| 2830 | if (do_background != 0 && i < num_trans && trans[i] < 255)
|
---|
| 2831 | {
|
---|
| 2832 | if (trans[i] == 0)
|
---|
| 2833 | png_create_colormap_entry(display, i, back_r, back_g,
|
---|
| 2834 | back_b, 0, output_encoding);
|
---|
| 2835 |
|
---|
| 2836 | else
|
---|
| 2837 | {
|
---|
| 2838 | /* Must compose the PNG file color in the color-map entry
|
---|
| 2839 | * on the sRGB color in 'back'.
|
---|
| 2840 | */
|
---|
| 2841 | png_create_colormap_entry(display, i,
|
---|
| 2842 | png_colormap_compose(display, colormap[i].red,
|
---|
| 2843 | P_FILE, trans[i], back_r, output_encoding),
|
---|
| 2844 | png_colormap_compose(display, colormap[i].green,
|
---|
| 2845 | P_FILE, trans[i], back_g, output_encoding),
|
---|
| 2846 | png_colormap_compose(display, colormap[i].blue,
|
---|
| 2847 | P_FILE, trans[i], back_b, output_encoding),
|
---|
| 2848 | output_encoding == P_LINEAR ? trans[i] * 257U :
|
---|
| 2849 | trans[i],
|
---|
| 2850 | output_encoding);
|
---|
| 2851 | }
|
---|
| 2852 | }
|
---|
| 2853 |
|
---|
| 2854 | else
|
---|
| 2855 | png_create_colormap_entry(display, i, colormap[i].red,
|
---|
| 2856 | colormap[i].green, colormap[i].blue,
|
---|
| 2857 | i < num_trans ? trans[i] : 255U, P_FILE/*8-bit*/);
|
---|
| 2858 | }
|
---|
| 2859 |
|
---|
| 2860 | /* The PNG data may have indices packed in fewer than 8 bits, it
|
---|
| 2861 | * must be expanded if so.
|
---|
| 2862 | */
|
---|
| 2863 | if (png_ptr->bit_depth < 8)
|
---|
| 2864 | png_set_packing(png_ptr);
|
---|
| 2865 | }
|
---|
| 2866 | break;
|
---|
| 2867 |
|
---|
| 2868 | default:
|
---|
| 2869 | png_error(png_ptr, "invalid PNG color type");
|
---|
| 2870 | /*NOT REACHED*/
|
---|
| 2871 | }
|
---|
| 2872 |
|
---|
| 2873 | /* Now deal with the output processing */
|
---|
| 2874 | if (expand_tRNS != 0 && png_ptr->num_trans > 0 &&
|
---|
| 2875 | (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) == 0)
|
---|
| 2876 | png_set_tRNS_to_alpha(png_ptr);
|
---|
| 2877 |
|
---|
| 2878 | switch (data_encoding)
|
---|
| 2879 | {
|
---|
| 2880 | case P_sRGB:
|
---|
| 2881 | /* Change to 8-bit sRGB */
|
---|
| 2882 | png_set_alpha_mode_fixed(png_ptr, PNG_ALPHA_PNG, PNG_GAMMA_sRGB);
|
---|
| 2883 | /* FALLTHROUGH */
|
---|
| 2884 |
|
---|
| 2885 | case P_FILE:
|
---|
| 2886 | if (png_ptr->bit_depth > 8)
|
---|
| 2887 | png_set_scale_16(png_ptr);
|
---|
| 2888 | break;
|
---|
| 2889 |
|
---|
| 2890 | #ifdef __GNUC__
|
---|
| 2891 | default:
|
---|
| 2892 | png_error(png_ptr, "bad data option (internal error)");
|
---|
| 2893 | #endif
|
---|
| 2894 | }
|
---|
| 2895 |
|
---|
| 2896 | if (cmap_entries > 256 || cmap_entries > image->colormap_entries)
|
---|
| 2897 | png_error(png_ptr, "color map overflow (BAD internal error)");
|
---|
| 2898 |
|
---|
| 2899 | image->colormap_entries = cmap_entries;
|
---|
| 2900 |
|
---|
| 2901 | /* Double check using the recorded background index */
|
---|
| 2902 | switch (output_processing)
|
---|
| 2903 | {
|
---|
| 2904 | case PNG_CMAP_NONE:
|
---|
| 2905 | if (background_index != PNG_CMAP_NONE_BACKGROUND)
|
---|
| 2906 | goto bad_background;
|
---|
| 2907 | break;
|
---|
| 2908 |
|
---|
| 2909 | case PNG_CMAP_GA:
|
---|
| 2910 | if (background_index != PNG_CMAP_GA_BACKGROUND)
|
---|
| 2911 | goto bad_background;
|
---|
| 2912 | break;
|
---|
| 2913 |
|
---|
| 2914 | case PNG_CMAP_TRANS:
|
---|
| 2915 | if (background_index >= cmap_entries ||
|
---|
| 2916 | background_index != PNG_CMAP_TRANS_BACKGROUND)
|
---|
| 2917 | goto bad_background;
|
---|
| 2918 | break;
|
---|
| 2919 |
|
---|
| 2920 | case PNG_CMAP_RGB:
|
---|
| 2921 | if (background_index != PNG_CMAP_RGB_BACKGROUND)
|
---|
| 2922 | goto bad_background;
|
---|
| 2923 | break;
|
---|
| 2924 |
|
---|
| 2925 | case PNG_CMAP_RGB_ALPHA:
|
---|
| 2926 | if (background_index != PNG_CMAP_RGB_ALPHA_BACKGROUND)
|
---|
| 2927 | goto bad_background;
|
---|
| 2928 | break;
|
---|
| 2929 |
|
---|
| 2930 | default:
|
---|
| 2931 | png_error(png_ptr, "bad processing option (internal error)");
|
---|
| 2932 |
|
---|
| 2933 | bad_background:
|
---|
| 2934 | png_error(png_ptr, "bad background index (internal error)");
|
---|
| 2935 | }
|
---|
| 2936 |
|
---|
| 2937 | display->colormap_processing = (int)output_processing;
|
---|
| 2938 |
|
---|
| 2939 | return 1/*ok*/;
|
---|
| 2940 | }
|
---|
| 2941 |
|
---|
| 2942 | /* The final part of the color-map read called from png_image_finish_read. */
|
---|
| 2943 | static int
|
---|
| 2944 | png_image_read_and_map(png_voidp argument)
|
---|
| 2945 | {
|
---|
| 2946 | png_image_read_control *display = png_voidcast(png_image_read_control*,
|
---|
| 2947 | argument);
|
---|
| 2948 | png_imagep image = display->image;
|
---|
| 2949 | png_structrp png_ptr = image->opaque->png_ptr;
|
---|
| 2950 | int passes;
|
---|
| 2951 |
|
---|
| 2952 | /* Called when the libpng data must be transformed into the color-mapped
|
---|
| 2953 | * form. There is a local row buffer in display->local and this routine must
|
---|
| 2954 | * do the interlace handling.
|
---|
| 2955 | */
|
---|
| 2956 | switch (png_ptr->interlaced)
|
---|
| 2957 | {
|
---|
| 2958 | case PNG_INTERLACE_NONE:
|
---|
| 2959 | passes = 1;
|
---|
| 2960 | break;
|
---|
| 2961 |
|
---|
| 2962 | case PNG_INTERLACE_ADAM7:
|
---|
| 2963 | passes = PNG_INTERLACE_ADAM7_PASSES;
|
---|
| 2964 | break;
|
---|
| 2965 |
|
---|
| 2966 | default:
|
---|
| 2967 | png_error(png_ptr, "unknown interlace type");
|
---|
| 2968 | }
|
---|
| 2969 |
|
---|
| 2970 | {
|
---|
| 2971 | png_uint_32 height = image->height;
|
---|
| 2972 | png_uint_32 width = image->width;
|
---|
| 2973 | int proc = display->colormap_processing;
|
---|
| 2974 | png_bytep first_row = png_voidcast(png_bytep, display->first_row);
|
---|
| 2975 | ptrdiff_t step_row = display->row_bytes;
|
---|
| 2976 | int pass;
|
---|
| 2977 |
|
---|
| 2978 | for (pass = 0; pass < passes; ++pass)
|
---|
| 2979 | {
|
---|
| 2980 | unsigned int startx, stepx, stepy;
|
---|
| 2981 | png_uint_32 y;
|
---|
| 2982 |
|
---|
| 2983 | if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
|
---|
| 2984 | {
|
---|
| 2985 | /* The row may be empty for a short image: */
|
---|
| 2986 | if (PNG_PASS_COLS(width, pass) == 0)
|
---|
| 2987 | continue;
|
---|
| 2988 |
|
---|
| 2989 | startx = PNG_PASS_START_COL(pass);
|
---|
| 2990 | stepx = PNG_PASS_COL_OFFSET(pass);
|
---|
| 2991 | y = PNG_PASS_START_ROW(pass);
|
---|
| 2992 | stepy = PNG_PASS_ROW_OFFSET(pass);
|
---|
| 2993 | }
|
---|
| 2994 |
|
---|
| 2995 | else
|
---|
| 2996 | {
|
---|
| 2997 | y = 0;
|
---|
| 2998 | startx = 0;
|
---|
| 2999 | stepx = stepy = 1;
|
---|
| 3000 | }
|
---|
| 3001 |
|
---|
| 3002 | for (; y<height; y += stepy)
|
---|
| 3003 | {
|
---|
| 3004 | png_bytep inrow = png_voidcast(png_bytep, display->local_row);
|
---|
| 3005 | png_bytep outrow = first_row + y * step_row;
|
---|
| 3006 | png_const_bytep end_row = outrow + width;
|
---|
| 3007 |
|
---|
| 3008 | /* Read read the libpng data into the temporary buffer. */
|
---|
| 3009 | png_read_row(png_ptr, inrow, NULL);
|
---|
| 3010 |
|
---|
| 3011 | /* Now process the row according to the processing option, note
|
---|
| 3012 | * that the caller verifies that the format of the libpng output
|
---|
| 3013 | * data is as required.
|
---|
| 3014 | */
|
---|
| 3015 | outrow += startx;
|
---|
| 3016 | switch (proc)
|
---|
| 3017 | {
|
---|
| 3018 | case PNG_CMAP_GA:
|
---|
| 3019 | for (; outrow < end_row; outrow += stepx)
|
---|
| 3020 | {
|
---|
| 3021 | /* The data is always in the PNG order */
|
---|
| 3022 | unsigned int gray = *inrow++;
|
---|
| 3023 | unsigned int alpha = *inrow++;
|
---|
| 3024 | unsigned int entry;
|
---|
| 3025 |
|
---|
| 3026 | /* NOTE: this code is copied as a comment in
|
---|
| 3027 | * make_ga_colormap above. Please update the
|
---|
| 3028 | * comment if you change this code!
|
---|
| 3029 | */
|
---|
| 3030 | if (alpha > 229) /* opaque */
|
---|
| 3031 | {
|
---|
| 3032 | entry = (231 * gray + 128) >> 8;
|
---|
| 3033 | }
|
---|
| 3034 | else if (alpha < 26) /* transparent */
|
---|
| 3035 | {
|
---|
| 3036 | entry = 231;
|
---|
| 3037 | }
|
---|
| 3038 | else /* partially opaque */
|
---|
| 3039 | {
|
---|
| 3040 | entry = 226 + 6 * PNG_DIV51(alpha) + PNG_DIV51(gray);
|
---|
| 3041 | }
|
---|
| 3042 |
|
---|
| 3043 | *outrow = (png_byte)entry;
|
---|
| 3044 | }
|
---|
| 3045 | break;
|
---|
| 3046 |
|
---|
| 3047 | case PNG_CMAP_TRANS:
|
---|
| 3048 | for (; outrow < end_row; outrow += stepx)
|
---|
| 3049 | {
|
---|
| 3050 | png_byte gray = *inrow++;
|
---|
| 3051 | png_byte alpha = *inrow++;
|
---|
| 3052 |
|
---|
| 3053 | if (alpha == 0)
|
---|
| 3054 | *outrow = PNG_CMAP_TRANS_BACKGROUND;
|
---|
| 3055 |
|
---|
| 3056 | else if (gray != PNG_CMAP_TRANS_BACKGROUND)
|
---|
| 3057 | *outrow = gray;
|
---|
| 3058 |
|
---|
| 3059 | else
|
---|
| 3060 | *outrow = (png_byte)(PNG_CMAP_TRANS_BACKGROUND+1);
|
---|
| 3061 | }
|
---|
| 3062 | break;
|
---|
| 3063 |
|
---|
| 3064 | case PNG_CMAP_RGB:
|
---|
| 3065 | for (; outrow < end_row; outrow += stepx)
|
---|
| 3066 | {
|
---|
| 3067 | *outrow = PNG_RGB_INDEX(inrow[0], inrow[1], inrow[2]);
|
---|
| 3068 | inrow += 3;
|
---|
| 3069 | }
|
---|
| 3070 | break;
|
---|
| 3071 |
|
---|
| 3072 | case PNG_CMAP_RGB_ALPHA:
|
---|
| 3073 | for (; outrow < end_row; outrow += stepx)
|
---|
| 3074 | {
|
---|
| 3075 | unsigned int alpha = inrow[3];
|
---|
| 3076 |
|
---|
| 3077 | /* Because the alpha entries only hold alpha==0.5 values
|
---|
| 3078 | * split the processing at alpha==0.25 (64) and 0.75
|
---|
| 3079 | * (196).
|
---|
| 3080 | */
|
---|
| 3081 |
|
---|
| 3082 | if (alpha >= 196)
|
---|
| 3083 | *outrow = PNG_RGB_INDEX(inrow[0], inrow[1],
|
---|
| 3084 | inrow[2]);
|
---|
| 3085 |
|
---|
| 3086 | else if (alpha < 64)
|
---|
| 3087 | *outrow = PNG_CMAP_RGB_ALPHA_BACKGROUND;
|
---|
| 3088 |
|
---|
| 3089 | else
|
---|
| 3090 | {
|
---|
| 3091 | /* Likewise there are three entries for each of r, g
|
---|
| 3092 | * and b. We could select the entry by popcount on
|
---|
| 3093 | * the top two bits on those architectures that
|
---|
| 3094 | * support it, this is what the code below does,
|
---|
| 3095 | * crudely.
|
---|
| 3096 | */
|
---|
| 3097 | unsigned int back_i = PNG_CMAP_RGB_ALPHA_BACKGROUND+1;
|
---|
| 3098 |
|
---|
| 3099 | /* Here are how the values map:
|
---|
| 3100 | *
|
---|
| 3101 | * 0x00 .. 0x3f -> 0
|
---|
| 3102 | * 0x40 .. 0xbf -> 1
|
---|
| 3103 | * 0xc0 .. 0xff -> 2
|
---|
| 3104 | *
|
---|
| 3105 | * So, as above with the explicit alpha checks, the
|
---|
| 3106 | * breakpoints are at 64 and 196.
|
---|
| 3107 | */
|
---|
| 3108 | if (inrow[0] & 0x80) back_i += 9; /* red */
|
---|
| 3109 | if (inrow[0] & 0x40) back_i += 9;
|
---|
| 3110 | if (inrow[0] & 0x80) back_i += 3; /* green */
|
---|
| 3111 | if (inrow[0] & 0x40) back_i += 3;
|
---|
| 3112 | if (inrow[0] & 0x80) back_i += 1; /* blue */
|
---|
| 3113 | if (inrow[0] & 0x40) back_i += 1;
|
---|
| 3114 |
|
---|
| 3115 | *outrow = (png_byte)back_i;
|
---|
| 3116 | }
|
---|
| 3117 |
|
---|
| 3118 | inrow += 4;
|
---|
| 3119 | }
|
---|
| 3120 | break;
|
---|
| 3121 |
|
---|
| 3122 | default:
|
---|
| 3123 | break;
|
---|
| 3124 | }
|
---|
| 3125 | }
|
---|
| 3126 | }
|
---|
| 3127 | }
|
---|
| 3128 |
|
---|
| 3129 | return 1;
|
---|
| 3130 | }
|
---|
| 3131 |
|
---|
| 3132 | static int
|
---|
| 3133 | png_image_read_colormapped(png_voidp argument)
|
---|
| 3134 | {
|
---|
| 3135 | png_image_read_control *display = png_voidcast(png_image_read_control*,
|
---|
| 3136 | argument);
|
---|
| 3137 | png_imagep image = display->image;
|
---|
| 3138 | png_controlp control = image->opaque;
|
---|
| 3139 | png_structrp png_ptr = control->png_ptr;
|
---|
| 3140 | png_inforp info_ptr = control->info_ptr;
|
---|
| 3141 |
|
---|
| 3142 | int passes = 0; /* As a flag */
|
---|
| 3143 |
|
---|
| 3144 | PNG_SKIP_CHUNKS(png_ptr);
|
---|
| 3145 |
|
---|
| 3146 | /* Update the 'info' structure and make sure the result is as required; first
|
---|
| 3147 | * make sure to turn on the interlace handling if it will be required
|
---|
| 3148 | * (because it can't be turned on *after* the call to png_read_update_info!)
|
---|
| 3149 | */
|
---|
| 3150 | if (display->colormap_processing == PNG_CMAP_NONE)
|
---|
| 3151 | passes = png_set_interlace_handling(png_ptr);
|
---|
| 3152 |
|
---|
| 3153 | png_read_update_info(png_ptr, info_ptr);
|
---|
| 3154 |
|
---|
| 3155 | /* The expected output can be deduced from the colormap_processing option. */
|
---|
| 3156 | switch (display->colormap_processing)
|
---|
| 3157 | {
|
---|
| 3158 | case PNG_CMAP_NONE:
|
---|
| 3159 | /* Output must be one channel and one byte per pixel, the output
|
---|
| 3160 | * encoding can be anything.
|
---|
| 3161 | */
|
---|
| 3162 | if ((info_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||
|
---|
| 3163 | info_ptr->color_type == PNG_COLOR_TYPE_GRAY) &&
|
---|
| 3164 | info_ptr->bit_depth == 8)
|
---|
| 3165 | break;
|
---|
| 3166 |
|
---|
| 3167 | goto bad_output;
|
---|
| 3168 |
|
---|
| 3169 | case PNG_CMAP_TRANS:
|
---|
| 3170 | case PNG_CMAP_GA:
|
---|
| 3171 | /* Output must be two channels and the 'G' one must be sRGB, the latter
|
---|
| 3172 | * can be checked with an exact number because it should have been set
|
---|
| 3173 | * to this number above!
|
---|
| 3174 | */
|
---|
| 3175 | if (info_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA &&
|
---|
| 3176 | info_ptr->bit_depth == 8 &&
|
---|
| 3177 | png_ptr->screen_gamma == PNG_GAMMA_sRGB &&
|
---|
| 3178 | image->colormap_entries == 256)
|
---|
| 3179 | break;
|
---|
| 3180 |
|
---|
| 3181 | goto bad_output;
|
---|
| 3182 |
|
---|
| 3183 | case PNG_CMAP_RGB:
|
---|
| 3184 | /* Output must be 8-bit sRGB encoded RGB */
|
---|
| 3185 | if (info_ptr->color_type == PNG_COLOR_TYPE_RGB &&
|
---|
| 3186 | info_ptr->bit_depth == 8 &&
|
---|
| 3187 | png_ptr->screen_gamma == PNG_GAMMA_sRGB &&
|
---|
| 3188 | image->colormap_entries == 216)
|
---|
| 3189 | break;
|
---|
| 3190 |
|
---|
| 3191 | goto bad_output;
|
---|
| 3192 |
|
---|
| 3193 | case PNG_CMAP_RGB_ALPHA:
|
---|
| 3194 | /* Output must be 8-bit sRGB encoded RGBA */
|
---|
| 3195 | if (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
|
---|
| 3196 | info_ptr->bit_depth == 8 &&
|
---|
| 3197 | png_ptr->screen_gamma == PNG_GAMMA_sRGB &&
|
---|
| 3198 | image->colormap_entries == 244 /* 216 + 1 + 27 */)
|
---|
| 3199 | break;
|
---|
| 3200 |
|
---|
| 3201 | goto bad_output;
|
---|
| 3202 |
|
---|
| 3203 | default:
|
---|
| 3204 | bad_output:
|
---|
| 3205 | png_error(png_ptr, "bad color-map processing (internal error)");
|
---|
| 3206 | }
|
---|
| 3207 |
|
---|
| 3208 | /* Now read the rows. Do this here if it is possible to read directly into
|
---|
| 3209 | * the output buffer, otherwise allocate a local row buffer of the maximum
|
---|
| 3210 | * size libpng requires and call the relevant processing routine safely.
|
---|
| 3211 | */
|
---|
| 3212 | {
|
---|
| 3213 | png_voidp first_row = display->buffer;
|
---|
| 3214 | ptrdiff_t row_bytes = display->row_stride;
|
---|
| 3215 |
|
---|
| 3216 | /* The following expression is designed to work correctly whether it gives
|
---|
| 3217 | * a signed or an unsigned result.
|
---|
| 3218 | */
|
---|
| 3219 | if (row_bytes < 0)
|
---|
| 3220 | {
|
---|
| 3221 | char *ptr = png_voidcast(char*, first_row);
|
---|
| 3222 | ptr += (image->height-1) * (-row_bytes);
|
---|
| 3223 | first_row = png_voidcast(png_voidp, ptr);
|
---|
| 3224 | }
|
---|
| 3225 |
|
---|
| 3226 | display->first_row = first_row;
|
---|
| 3227 | display->row_bytes = row_bytes;
|
---|
| 3228 | }
|
---|
| 3229 |
|
---|
| 3230 | if (passes == 0)
|
---|
| 3231 | {
|
---|
| 3232 | int result;
|
---|
| 3233 | png_voidp row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr));
|
---|
| 3234 |
|
---|
| 3235 | display->local_row = row;
|
---|
| 3236 | result = png_safe_execute(image, png_image_read_and_map, display);
|
---|
| 3237 | display->local_row = NULL;
|
---|
| 3238 | png_free(png_ptr, row);
|
---|
| 3239 |
|
---|
| 3240 | return result;
|
---|
| 3241 | }
|
---|
| 3242 |
|
---|
| 3243 | else
|
---|
| 3244 | {
|
---|
| 3245 | png_alloc_size_t row_bytes = (png_alloc_size_t)display->row_bytes;
|
---|
| 3246 |
|
---|
| 3247 | while (--passes >= 0)
|
---|
| 3248 | {
|
---|
| 3249 | png_uint_32 y = image->height;
|
---|
| 3250 | png_bytep row = png_voidcast(png_bytep, display->first_row);
|
---|
| 3251 |
|
---|
| 3252 | for (; y > 0; --y)
|
---|
| 3253 | {
|
---|
| 3254 | png_read_row(png_ptr, row, NULL);
|
---|
| 3255 | row += row_bytes;
|
---|
| 3256 | }
|
---|
| 3257 | }
|
---|
| 3258 |
|
---|
| 3259 | return 1;
|
---|
| 3260 | }
|
---|
| 3261 | }
|
---|
| 3262 |
|
---|
| 3263 | /* Just the row reading part of png_image_read. */
|
---|
| 3264 | static int
|
---|
| 3265 | png_image_read_composite(png_voidp argument)
|
---|
| 3266 | {
|
---|
| 3267 | png_image_read_control *display = png_voidcast(png_image_read_control*,
|
---|
| 3268 | argument);
|
---|
| 3269 | png_imagep image = display->image;
|
---|
| 3270 | png_structrp png_ptr = image->opaque->png_ptr;
|
---|
| 3271 | int passes;
|
---|
| 3272 |
|
---|
| 3273 | switch (png_ptr->interlaced)
|
---|
| 3274 | {
|
---|
| 3275 | case PNG_INTERLACE_NONE:
|
---|
| 3276 | passes = 1;
|
---|
| 3277 | break;
|
---|
| 3278 |
|
---|
| 3279 | case PNG_INTERLACE_ADAM7:
|
---|
| 3280 | passes = PNG_INTERLACE_ADAM7_PASSES;
|
---|
| 3281 | break;
|
---|
| 3282 |
|
---|
| 3283 | default:
|
---|
| 3284 | png_error(png_ptr, "unknown interlace type");
|
---|
| 3285 | }
|
---|
| 3286 |
|
---|
| 3287 | {
|
---|
| 3288 | png_uint_32 height = image->height;
|
---|
| 3289 | png_uint_32 width = image->width;
|
---|
| 3290 | ptrdiff_t step_row = display->row_bytes;
|
---|
| 3291 | unsigned int channels =
|
---|
| 3292 | (image->format & PNG_FORMAT_FLAG_COLOR) != 0 ? 3 : 1;
|
---|
| 3293 | int pass;
|
---|
| 3294 |
|
---|
| 3295 | for (pass = 0; pass < passes; ++pass)
|
---|
| 3296 | {
|
---|
| 3297 | unsigned int startx, stepx, stepy;
|
---|
| 3298 | png_uint_32 y;
|
---|
| 3299 |
|
---|
| 3300 | if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
|
---|
| 3301 | {
|
---|
| 3302 | /* The row may be empty for a short image: */
|
---|
| 3303 | if (PNG_PASS_COLS(width, pass) == 0)
|
---|
| 3304 | continue;
|
---|
| 3305 |
|
---|
| 3306 | startx = PNG_PASS_START_COL(pass) * channels;
|
---|
| 3307 | stepx = PNG_PASS_COL_OFFSET(pass) * channels;
|
---|
| 3308 | y = PNG_PASS_START_ROW(pass);
|
---|
| 3309 | stepy = PNG_PASS_ROW_OFFSET(pass);
|
---|
| 3310 | }
|
---|
| 3311 |
|
---|
| 3312 | else
|
---|
| 3313 | {
|
---|
| 3314 | y = 0;
|
---|
| 3315 | startx = 0;
|
---|
| 3316 | stepx = channels;
|
---|
| 3317 | stepy = 1;
|
---|
| 3318 | }
|
---|
| 3319 |
|
---|
| 3320 | for (; y<height; y += stepy)
|
---|
| 3321 | {
|
---|
| 3322 | png_bytep inrow = png_voidcast(png_bytep, display->local_row);
|
---|
| 3323 | png_bytep outrow;
|
---|
| 3324 | png_const_bytep end_row;
|
---|
| 3325 |
|
---|
| 3326 | /* Read the row, which is packed: */
|
---|
| 3327 | png_read_row(png_ptr, inrow, NULL);
|
---|
| 3328 |
|
---|
| 3329 | outrow = png_voidcast(png_bytep, display->first_row);
|
---|
| 3330 | outrow += y * step_row;
|
---|
| 3331 | end_row = outrow + width * channels;
|
---|
| 3332 |
|
---|
| 3333 | /* Now do the composition on each pixel in this row. */
|
---|
| 3334 | outrow += startx;
|
---|
| 3335 | for (; outrow < end_row; outrow += stepx)
|
---|
| 3336 | {
|
---|
| 3337 | png_byte alpha = inrow[channels];
|
---|
| 3338 |
|
---|
| 3339 | if (alpha > 0) /* else no change to the output */
|
---|
| 3340 | {
|
---|
| 3341 | unsigned int c;
|
---|
| 3342 |
|
---|
| 3343 | for (c=0; c<channels; ++c)
|
---|
| 3344 | {
|
---|
| 3345 | png_uint_32 component = inrow[c];
|
---|
| 3346 |
|
---|
| 3347 | if (alpha < 255) /* else just use component */
|
---|
| 3348 | {
|
---|
| 3349 | /* This is PNG_OPTIMIZED_ALPHA, the component value
|
---|
| 3350 | * is a linear 8-bit value. Combine this with the
|
---|
| 3351 | * current outrow[c] value which is sRGB encoded.
|
---|
| 3352 | * Arithmetic here is 16-bits to preserve the output
|
---|
| 3353 | * values correctly.
|
---|
| 3354 | */
|
---|
| 3355 | component *= 257*255; /* =65535 */
|
---|
| 3356 | component += (255-alpha)*png_sRGB_table[outrow[c]];
|
---|
| 3357 |
|
---|
| 3358 | /* So 'component' is scaled by 255*65535 and is
|
---|
| 3359 | * therefore appropriate for the sRGB to linear
|
---|
| 3360 | * conversion table.
|
---|
| 3361 | */
|
---|
| 3362 | component = PNG_sRGB_FROM_LINEAR(component);
|
---|
| 3363 | }
|
---|
| 3364 |
|
---|
| 3365 | outrow[c] = (png_byte)component;
|
---|
| 3366 | }
|
---|
| 3367 | }
|
---|
| 3368 |
|
---|
| 3369 | inrow += channels+1; /* components and alpha channel */
|
---|
| 3370 | }
|
---|
| 3371 | }
|
---|
| 3372 | }
|
---|
| 3373 | }
|
---|
| 3374 |
|
---|
| 3375 | return 1;
|
---|
| 3376 | }
|
---|
| 3377 |
|
---|
| 3378 | /* The do_local_background case; called when all the following transforms are to
|
---|
| 3379 | * be done:
|
---|
| 3380 | *
|
---|
| 3381 | * PNG_RGB_TO_GRAY
|
---|
| 3382 | * PNG_COMPOSITE
|
---|
| 3383 | * PNG_GAMMA
|
---|
| 3384 | *
|
---|
| 3385 | * This is a work-around for the fact that both the PNG_RGB_TO_GRAY and
|
---|
| 3386 | * PNG_COMPOSITE code performs gamma correction, so we get double gamma
|
---|
| 3387 | * correction. The fix-up is to prevent the PNG_COMPOSITE operation from
|
---|
| 3388 | * happening inside libpng, so this routine sees an 8 or 16-bit gray+alpha
|
---|
| 3389 | * row and handles the removal or pre-multiplication of the alpha channel.
|
---|
| 3390 | */
|
---|
| 3391 | static int
|
---|
| 3392 | png_image_read_background(png_voidp argument)
|
---|
| 3393 | {
|
---|
| 3394 | png_image_read_control *display = png_voidcast(png_image_read_control*,
|
---|
| 3395 | argument);
|
---|
| 3396 | png_imagep image = display->image;
|
---|
| 3397 | png_structrp png_ptr = image->opaque->png_ptr;
|
---|
| 3398 | png_inforp info_ptr = image->opaque->info_ptr;
|
---|
| 3399 | png_uint_32 height = image->height;
|
---|
| 3400 | png_uint_32 width = image->width;
|
---|
| 3401 | int pass, passes;
|
---|
| 3402 |
|
---|
| 3403 | /* Double check the convoluted logic below. We expect to get here with
|
---|
| 3404 | * libpng doing rgb to gray and gamma correction but background processing
|
---|
| 3405 | * left to the png_image_read_background function. The rows libpng produce
|
---|
| 3406 | * might be 8 or 16-bit but should always have two channels; gray plus alpha.
|
---|
| 3407 | */
|
---|
| 3408 | if ((png_ptr->transformations & PNG_RGB_TO_GRAY) == 0)
|
---|
| 3409 | png_error(png_ptr, "lost rgb to gray");
|
---|
| 3410 |
|
---|
| 3411 | if ((png_ptr->transformations & PNG_COMPOSE) != 0)
|
---|
| 3412 | png_error(png_ptr, "unexpected compose");
|
---|
| 3413 |
|
---|
| 3414 | if (png_get_channels(png_ptr, info_ptr) != 2)
|
---|
| 3415 | png_error(png_ptr, "lost/gained channels");
|
---|
| 3416 |
|
---|
| 3417 | /* Expect the 8-bit case to always remove the alpha channel */
|
---|
| 3418 | if ((image->format & PNG_FORMAT_FLAG_LINEAR) == 0 &&
|
---|
| 3419 | (image->format & PNG_FORMAT_FLAG_ALPHA) != 0)
|
---|
| 3420 | png_error(png_ptr, "unexpected 8-bit transformation");
|
---|
| 3421 |
|
---|
| 3422 | switch (png_ptr->interlaced)
|
---|
| 3423 | {
|
---|
| 3424 | case PNG_INTERLACE_NONE:
|
---|
| 3425 | passes = 1;
|
---|
| 3426 | break;
|
---|
| 3427 |
|
---|
| 3428 | case PNG_INTERLACE_ADAM7:
|
---|
| 3429 | passes = PNG_INTERLACE_ADAM7_PASSES;
|
---|
| 3430 | break;
|
---|
| 3431 |
|
---|
| 3432 | default:
|
---|
| 3433 | png_error(png_ptr, "unknown interlace type");
|
---|
| 3434 | }
|
---|
| 3435 |
|
---|
| 3436 | /* Use direct access to info_ptr here because otherwise the simplified API
|
---|
| 3437 | * would require PNG_EASY_ACCESS_SUPPORTED (just for this.) Note this is
|
---|
| 3438 | * checking the value after libpng expansions, not the original value in the
|
---|
| 3439 | * PNG.
|
---|
| 3440 | */
|
---|
| 3441 | switch (info_ptr->bit_depth)
|
---|
| 3442 | {
|
---|
| 3443 | case 8:
|
---|
| 3444 | /* 8-bit sRGB gray values with an alpha channel; the alpha channel is
|
---|
| 3445 | * to be removed by composing on a background: either the row if
|
---|
| 3446 | * display->background is NULL or display->background->green if not.
|
---|
| 3447 | * Unlike the code above ALPHA_OPTIMIZED has *not* been done.
|
---|
| 3448 | */
|
---|
| 3449 | {
|
---|
| 3450 | png_bytep first_row = png_voidcast(png_bytep, display->first_row);
|
---|
| 3451 | ptrdiff_t step_row = display->row_bytes;
|
---|
| 3452 |
|
---|
| 3453 | for (pass = 0; pass < passes; ++pass)
|
---|
| 3454 | {
|
---|
| 3455 | png_bytep row = png_voidcast(png_bytep, display->first_row);
|
---|
| 3456 | unsigned int startx, stepx, stepy;
|
---|
| 3457 | png_uint_32 y;
|
---|
| 3458 |
|
---|
| 3459 | if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
|
---|
| 3460 | {
|
---|
| 3461 | /* The row may be empty for a short image: */
|
---|
| 3462 | if (PNG_PASS_COLS(width, pass) == 0)
|
---|
| 3463 | continue;
|
---|
| 3464 |
|
---|
| 3465 | startx = PNG_PASS_START_COL(pass);
|
---|
| 3466 | stepx = PNG_PASS_COL_OFFSET(pass);
|
---|
| 3467 | y = PNG_PASS_START_ROW(pass);
|
---|
| 3468 | stepy = PNG_PASS_ROW_OFFSET(pass);
|
---|
| 3469 | }
|
---|
| 3470 |
|
---|
| 3471 | else
|
---|
| 3472 | {
|
---|
| 3473 | y = 0;
|
---|
| 3474 | startx = 0;
|
---|
| 3475 | stepx = stepy = 1;
|
---|
| 3476 | }
|
---|
| 3477 |
|
---|
| 3478 | if (display->background == NULL)
|
---|
| 3479 | {
|
---|
| 3480 | for (; y<height; y += stepy)
|
---|
| 3481 | {
|
---|
| 3482 | png_bytep inrow = png_voidcast(png_bytep,
|
---|
| 3483 | display->local_row);
|
---|
| 3484 | png_bytep outrow = first_row + y * step_row;
|
---|
| 3485 | png_const_bytep end_row = outrow + width;
|
---|
| 3486 |
|
---|
| 3487 | /* Read the row, which is packed: */
|
---|
| 3488 | png_read_row(png_ptr, inrow, NULL);
|
---|
| 3489 |
|
---|
| 3490 | /* Now do the composition on each pixel in this row. */
|
---|
| 3491 | outrow += startx;
|
---|
| 3492 | for (; outrow < end_row; outrow += stepx)
|
---|
| 3493 | {
|
---|
| 3494 | png_byte alpha = inrow[1];
|
---|
| 3495 |
|
---|
| 3496 | if (alpha > 0) /* else no change to the output */
|
---|
| 3497 | {
|
---|
| 3498 | png_uint_32 component = inrow[0];
|
---|
| 3499 |
|
---|
| 3500 | if (alpha < 255) /* else just use component */
|
---|
| 3501 | {
|
---|
| 3502 | /* Since PNG_OPTIMIZED_ALPHA was not set it is
|
---|
| 3503 | * necessary to invert the sRGB transfer
|
---|
| 3504 | * function and multiply the alpha out.
|
---|
| 3505 | */
|
---|
| 3506 | component = png_sRGB_table[component] * alpha;
|
---|
| 3507 | component += png_sRGB_table[outrow[0]] *
|
---|
| 3508 | (255-alpha);
|
---|
| 3509 | component = PNG_sRGB_FROM_LINEAR(component);
|
---|
| 3510 | }
|
---|
| 3511 |
|
---|
| 3512 | outrow[0] = (png_byte)component;
|
---|
| 3513 | }
|
---|
| 3514 |
|
---|
| 3515 | inrow += 2; /* gray and alpha channel */
|
---|
| 3516 | }
|
---|
| 3517 | }
|
---|
| 3518 | }
|
---|
| 3519 |
|
---|
| 3520 | else /* constant background value */
|
---|
| 3521 | {
|
---|
| 3522 | png_byte background8 = display->background->green;
|
---|
| 3523 | png_uint_16 background = png_sRGB_table[background8];
|
---|
| 3524 |
|
---|
| 3525 | for (; y<height; y += stepy)
|
---|
| 3526 | {
|
---|
| 3527 | png_bytep inrow = png_voidcast(png_bytep,
|
---|
| 3528 | display->local_row);
|
---|
| 3529 | png_bytep outrow = first_row + y * step_row;
|
---|
| 3530 | png_const_bytep end_row = outrow + width;
|
---|
| 3531 |
|
---|
| 3532 | /* Read the row, which is packed: */
|
---|
| 3533 | png_read_row(png_ptr, inrow, NULL);
|
---|
| 3534 |
|
---|
| 3535 | /* Now do the composition on each pixel in this row. */
|
---|
| 3536 | outrow += startx;
|
---|
| 3537 | for (; outrow < end_row; outrow += stepx)
|
---|
| 3538 | {
|
---|
| 3539 | png_byte alpha = inrow[1];
|
---|
| 3540 |
|
---|
| 3541 | if (alpha > 0) /* else use background */
|
---|
| 3542 | {
|
---|
| 3543 | png_uint_32 component = inrow[0];
|
---|
| 3544 |
|
---|
| 3545 | if (alpha < 255) /* else just use component */
|
---|
| 3546 | {
|
---|
| 3547 | component = png_sRGB_table[component] * alpha;
|
---|
| 3548 | component += background * (255-alpha);
|
---|
| 3549 | component = PNG_sRGB_FROM_LINEAR(component);
|
---|
| 3550 | }
|
---|
| 3551 |
|
---|
| 3552 | outrow[0] = (png_byte)component;
|
---|
| 3553 | }
|
---|
| 3554 |
|
---|
| 3555 | else
|
---|
| 3556 | outrow[0] = background8;
|
---|
| 3557 |
|
---|
| 3558 | inrow += 2; /* gray and alpha channel */
|
---|
| 3559 | }
|
---|
| 3560 |
|
---|
| 3561 | row += display->row_bytes;
|
---|
| 3562 | }
|
---|
| 3563 | }
|
---|
| 3564 | }
|
---|
| 3565 | }
|
---|
| 3566 | break;
|
---|
| 3567 |
|
---|
| 3568 | case 16:
|
---|
| 3569 | /* 16-bit linear with pre-multiplied alpha; the pre-multiplication must
|
---|
| 3570 | * still be done and, maybe, the alpha channel removed. This code also
|
---|
| 3571 | * handles the alpha-first option.
|
---|
| 3572 | */
|
---|
| 3573 | {
|
---|
| 3574 | png_uint_16p first_row = png_voidcast(png_uint_16p,
|
---|
| 3575 | display->first_row);
|
---|
| 3576 | /* The division by two is safe because the caller passed in a
|
---|
| 3577 | * stride which was multiplied by 2 (below) to get row_bytes.
|
---|
| 3578 | */
|
---|
| 3579 | ptrdiff_t step_row = display->row_bytes / 2;
|
---|
| 3580 | unsigned int preserve_alpha = (image->format &
|
---|
| 3581 | PNG_FORMAT_FLAG_ALPHA) != 0;
|
---|
| 3582 | unsigned int outchannels = 1U+preserve_alpha;
|
---|
| 3583 | int swap_alpha = 0;
|
---|
| 3584 |
|
---|
| 3585 | # ifdef PNG_SIMPLIFIED_READ_AFIRST_SUPPORTED
|
---|
| 3586 | if (preserve_alpha != 0 &&
|
---|
| 3587 | (image->format & PNG_FORMAT_FLAG_AFIRST) != 0)
|
---|
| 3588 | swap_alpha = 1;
|
---|
| 3589 | # endif
|
---|
| 3590 |
|
---|
| 3591 | for (pass = 0; pass < passes; ++pass)
|
---|
| 3592 | {
|
---|
| 3593 | unsigned int startx, stepx, stepy;
|
---|
| 3594 | png_uint_32 y;
|
---|
| 3595 |
|
---|
| 3596 | /* The 'x' start and step are adjusted to output components here.
|
---|
| 3597 | */
|
---|
| 3598 | if (png_ptr->interlaced == PNG_INTERLACE_ADAM7)
|
---|
| 3599 | {
|
---|
| 3600 | /* The row may be empty for a short image: */
|
---|
| 3601 | if (PNG_PASS_COLS(width, pass) == 0)
|
---|
| 3602 | continue;
|
---|
| 3603 |
|
---|
| 3604 | startx = PNG_PASS_START_COL(pass) * outchannels;
|
---|
| 3605 | stepx = PNG_PASS_COL_OFFSET(pass) * outchannels;
|
---|
| 3606 | y = PNG_PASS_START_ROW(pass);
|
---|
| 3607 | stepy = PNG_PASS_ROW_OFFSET(pass);
|
---|
| 3608 | }
|
---|
| 3609 |
|
---|
| 3610 | else
|
---|
| 3611 | {
|
---|
| 3612 | y = 0;
|
---|
| 3613 | startx = 0;
|
---|
| 3614 | stepx = outchannels;
|
---|
| 3615 | stepy = 1;
|
---|
| 3616 | }
|
---|
| 3617 |
|
---|
| 3618 | for (; y<height; y += stepy)
|
---|
| 3619 | {
|
---|
| 3620 | png_const_uint_16p inrow;
|
---|
| 3621 | png_uint_16p outrow = first_row + y*step_row;
|
---|
| 3622 | png_uint_16p end_row = outrow + width * outchannels;
|
---|
| 3623 |
|
---|
| 3624 | /* Read the row, which is packed: */
|
---|
| 3625 | png_read_row(png_ptr, png_voidcast(png_bytep,
|
---|
| 3626 | display->local_row), NULL);
|
---|
| 3627 | inrow = png_voidcast(png_const_uint_16p, display->local_row);
|
---|
| 3628 |
|
---|
| 3629 | /* Now do the pre-multiplication on each pixel in this row.
|
---|
| 3630 | */
|
---|
| 3631 | outrow += startx;
|
---|
| 3632 | for (; outrow < end_row; outrow += stepx)
|
---|
| 3633 | {
|
---|
| 3634 | png_uint_32 component = inrow[0];
|
---|
| 3635 | png_uint_16 alpha = inrow[1];
|
---|
| 3636 |
|
---|
| 3637 | if (alpha > 0) /* else 0 */
|
---|
| 3638 | {
|
---|
| 3639 | if (alpha < 65535) /* else just use component */
|
---|
| 3640 | {
|
---|
| 3641 | component *= alpha;
|
---|
| 3642 | component += 32767;
|
---|
| 3643 | component /= 65535;
|
---|
| 3644 | }
|
---|
| 3645 | }
|
---|
| 3646 |
|
---|
| 3647 | else
|
---|
| 3648 | component = 0;
|
---|
| 3649 |
|
---|
| 3650 | outrow[swap_alpha] = (png_uint_16)component;
|
---|
| 3651 | if (preserve_alpha != 0)
|
---|
| 3652 | outrow[1 ^ swap_alpha] = alpha;
|
---|
| 3653 |
|
---|
| 3654 | inrow += 2; /* components and alpha channel */
|
---|
| 3655 | }
|
---|
| 3656 | }
|
---|
| 3657 | }
|
---|
| 3658 | }
|
---|
| 3659 | break;
|
---|
| 3660 |
|
---|
| 3661 | #ifdef __GNUC__
|
---|
| 3662 | default:
|
---|
| 3663 | png_error(png_ptr, "unexpected bit depth");
|
---|
| 3664 | #endif
|
---|
| 3665 | }
|
---|
| 3666 |
|
---|
| 3667 | return 1;
|
---|
| 3668 | }
|
---|
| 3669 |
|
---|
| 3670 | /* The guts of png_image_finish_read as a png_safe_execute callback. */
|
---|
| 3671 | static int
|
---|
| 3672 | png_image_read_direct(png_voidp argument)
|
---|
| 3673 | {
|
---|
| 3674 | png_image_read_control *display = png_voidcast(png_image_read_control*,
|
---|
| 3675 | argument);
|
---|
| 3676 | png_imagep image = display->image;
|
---|
| 3677 | png_structrp png_ptr = image->opaque->png_ptr;
|
---|
| 3678 | png_inforp info_ptr = image->opaque->info_ptr;
|
---|
| 3679 |
|
---|
| 3680 | png_uint_32 format = image->format;
|
---|
| 3681 | int linear = (format & PNG_FORMAT_FLAG_LINEAR) != 0;
|
---|
| 3682 | int do_local_compose = 0;
|
---|
| 3683 | int do_local_background = 0; /* to avoid double gamma correction bug */
|
---|
| 3684 | int passes = 0;
|
---|
| 3685 |
|
---|
| 3686 | /* Add transforms to ensure the correct output format is produced then check
|
---|
| 3687 | * that the required implementation support is there. Always expand; always
|
---|
| 3688 | * need 8 bits minimum, no palette and expanded tRNS.
|
---|
| 3689 | */
|
---|
| 3690 | png_set_expand(png_ptr);
|
---|
| 3691 |
|
---|
| 3692 | /* Now check the format to see if it was modified. */
|
---|
| 3693 | {
|
---|
| 3694 | png_uint_32 base_format = png_image_format(png_ptr) &
|
---|
| 3695 | ~PNG_FORMAT_FLAG_COLORMAP /* removed by png_set_expand */;
|
---|
| 3696 | png_uint_32 change = format ^ base_format;
|
---|
| 3697 | png_fixed_point output_gamma;
|
---|
| 3698 | int mode; /* alpha mode */
|
---|
| 3699 |
|
---|
| 3700 | /* Do this first so that we have a record if rgb to gray is happening. */
|
---|
| 3701 | if ((change & PNG_FORMAT_FLAG_COLOR) != 0)
|
---|
| 3702 | {
|
---|
| 3703 | /* gray<->color transformation required. */
|
---|
| 3704 | if ((format & PNG_FORMAT_FLAG_COLOR) != 0)
|
---|
| 3705 | png_set_gray_to_rgb(png_ptr);
|
---|
| 3706 |
|
---|
| 3707 | else
|
---|
| 3708 | {
|
---|
| 3709 | /* libpng can't do both rgb to gray and
|
---|
| 3710 | * background/pre-multiplication if there is also significant gamma
|
---|
| 3711 | * correction, because both operations require linear colors and
|
---|
| 3712 | * the code only supports one transform doing the gamma correction.
|
---|
| 3713 | * Handle this by doing the pre-multiplication or background
|
---|
| 3714 | * operation in this code, if necessary.
|
---|
| 3715 | *
|
---|
| 3716 | * TODO: fix this by rewriting pngrtran.c (!)
|
---|
| 3717 | *
|
---|
| 3718 | * For the moment (given that fixing this in pngrtran.c is an
|
---|
| 3719 | * enormous change) 'do_local_background' is used to indicate that
|
---|
| 3720 | * the problem exists.
|
---|
| 3721 | */
|
---|
| 3722 | if ((base_format & PNG_FORMAT_FLAG_ALPHA) != 0)
|
---|
| 3723 | do_local_background = 1/*maybe*/;
|
---|
| 3724 |
|
---|
| 3725 | png_set_rgb_to_gray_fixed(png_ptr, PNG_ERROR_ACTION_NONE,
|
---|
| 3726 | PNG_RGB_TO_GRAY_DEFAULT, PNG_RGB_TO_GRAY_DEFAULT);
|
---|
| 3727 | }
|
---|
| 3728 |
|
---|
| 3729 | change &= ~PNG_FORMAT_FLAG_COLOR;
|
---|
| 3730 | }
|
---|
| 3731 |
|
---|
| 3732 | /* Set the gamma appropriately, linear for 16-bit input, sRGB otherwise.
|
---|
| 3733 | */
|
---|
| 3734 | {
|
---|
| 3735 | png_fixed_point input_gamma_default;
|
---|
| 3736 |
|
---|
| 3737 | if ((base_format & PNG_FORMAT_FLAG_LINEAR) != 0 &&
|
---|
| 3738 | (image->flags & PNG_IMAGE_FLAG_16BIT_sRGB) == 0)
|
---|
| 3739 | input_gamma_default = PNG_GAMMA_LINEAR;
|
---|
| 3740 | else
|
---|
| 3741 | input_gamma_default = PNG_DEFAULT_sRGB;
|
---|
| 3742 |
|
---|
| 3743 | /* Call png_set_alpha_mode to set the default for the input gamma; the
|
---|
| 3744 | * output gamma is set by a second call below.
|
---|
| 3745 | */
|
---|
| 3746 | png_set_alpha_mode_fixed(png_ptr, PNG_ALPHA_PNG, input_gamma_default);
|
---|
| 3747 | }
|
---|
| 3748 |
|
---|
| 3749 | if (linear != 0)
|
---|
| 3750 | {
|
---|
| 3751 | /* If there *is* an alpha channel in the input it must be multiplied
|
---|
| 3752 | * out; use PNG_ALPHA_STANDARD, otherwise just use PNG_ALPHA_PNG.
|
---|
| 3753 | */
|
---|
| 3754 | if ((base_format & PNG_FORMAT_FLAG_ALPHA) != 0)
|
---|
| 3755 | mode = PNG_ALPHA_STANDARD; /* associated alpha */
|
---|
| 3756 |
|
---|
| 3757 | else
|
---|
| 3758 | mode = PNG_ALPHA_PNG;
|
---|
| 3759 |
|
---|
| 3760 | output_gamma = PNG_GAMMA_LINEAR;
|
---|
| 3761 | }
|
---|
| 3762 |
|
---|
| 3763 | else
|
---|
| 3764 | {
|
---|
| 3765 | mode = PNG_ALPHA_PNG;
|
---|
| 3766 | output_gamma = PNG_DEFAULT_sRGB;
|
---|
| 3767 | }
|
---|
| 3768 |
|
---|
| 3769 | if ((change & PNG_FORMAT_FLAG_ASSOCIATED_ALPHA) != 0)
|
---|
| 3770 | {
|
---|
| 3771 | mode = PNG_ALPHA_OPTIMIZED;
|
---|
| 3772 | change &= ~PNG_FORMAT_FLAG_ASSOCIATED_ALPHA;
|
---|
| 3773 | }
|
---|
| 3774 |
|
---|
| 3775 | /* If 'do_local_background' is set check for the presence of gamma
|
---|
| 3776 | * correction; this is part of the work-round for the libpng bug
|
---|
| 3777 | * described above.
|
---|
| 3778 | *
|
---|
| 3779 | * TODO: fix libpng and remove this.
|
---|
| 3780 | */
|
---|
| 3781 | if (do_local_background != 0)
|
---|
| 3782 | {
|
---|
| 3783 | png_fixed_point gtest;
|
---|
| 3784 |
|
---|
| 3785 | /* This is 'png_gamma_threshold' from pngrtran.c; the test used for
|
---|
| 3786 | * gamma correction, the screen gamma hasn't been set on png_struct
|
---|
| 3787 | * yet; it's set below. png_struct::gamma, however, is set to the
|
---|
| 3788 | * final value.
|
---|
| 3789 | */
|
---|
| 3790 | if (png_muldiv(>est, output_gamma, png_ptr->colorspace.gamma,
|
---|
| 3791 | PNG_FP_1) != 0 && png_gamma_significant(gtest) == 0)
|
---|
| 3792 | do_local_background = 0;
|
---|
| 3793 |
|
---|
| 3794 | else if (mode == PNG_ALPHA_STANDARD)
|
---|
| 3795 | {
|
---|
| 3796 | do_local_background = 2/*required*/;
|
---|
| 3797 | mode = PNG_ALPHA_PNG; /* prevent libpng doing it */
|
---|
| 3798 | }
|
---|
| 3799 |
|
---|
| 3800 | /* else leave as 1 for the checks below */
|
---|
| 3801 | }
|
---|
| 3802 |
|
---|
| 3803 | /* If the bit-depth changes then handle that here. */
|
---|
| 3804 | if ((change & PNG_FORMAT_FLAG_LINEAR) != 0)
|
---|
| 3805 | {
|
---|
| 3806 | if (linear != 0 /*16-bit output*/)
|
---|
| 3807 | png_set_expand_16(png_ptr);
|
---|
| 3808 |
|
---|
| 3809 | else /* 8-bit output */
|
---|
| 3810 | png_set_scale_16(png_ptr);
|
---|
| 3811 |
|
---|
| 3812 | change &= ~PNG_FORMAT_FLAG_LINEAR;
|
---|
| 3813 | }
|
---|
| 3814 |
|
---|
| 3815 | /* Now the background/alpha channel changes. */
|
---|
| 3816 | if ((change & PNG_FORMAT_FLAG_ALPHA) != 0)
|
---|
| 3817 | {
|
---|
| 3818 | /* Removing an alpha channel requires composition for the 8-bit
|
---|
| 3819 | * formats; for the 16-bit it is already done, above, by the
|
---|
| 3820 | * pre-multiplication and the channel just needs to be stripped.
|
---|
| 3821 | */
|
---|
| 3822 | if ((base_format & PNG_FORMAT_FLAG_ALPHA) != 0)
|
---|
| 3823 | {
|
---|
| 3824 | /* If RGB->gray is happening the alpha channel must be left and the
|
---|
| 3825 | * operation completed locally.
|
---|
| 3826 | *
|
---|
| 3827 | * TODO: fix libpng and remove this.
|
---|
| 3828 | */
|
---|
| 3829 | if (do_local_background != 0)
|
---|
| 3830 | do_local_background = 2/*required*/;
|
---|
| 3831 |
|
---|
| 3832 | /* 16-bit output: just remove the channel */
|
---|
| 3833 | else if (linear != 0) /* compose on black (well, pre-multiply) */
|
---|
| 3834 | png_set_strip_alpha(png_ptr);
|
---|
| 3835 |
|
---|
| 3836 | /* 8-bit output: do an appropriate compose */
|
---|
| 3837 | else if (display->background != NULL)
|
---|
| 3838 | {
|
---|
| 3839 | png_color_16 c;
|
---|
| 3840 |
|
---|
| 3841 | c.index = 0; /*unused*/
|
---|
| 3842 | c.red = display->background->red;
|
---|
| 3843 | c.green = display->background->green;
|
---|
| 3844 | c.blue = display->background->blue;
|
---|
| 3845 | c.gray = display->background->green;
|
---|
| 3846 |
|
---|
| 3847 | /* This is always an 8-bit sRGB value, using the 'green' channel
|
---|
| 3848 | * for gray is much better than calculating the luminance here;
|
---|
| 3849 | * we can get off-by-one errors in that calculation relative to
|
---|
| 3850 | * the app expectations and that will show up in transparent
|
---|
| 3851 | * pixels.
|
---|
| 3852 | */
|
---|
| 3853 | png_set_background_fixed(png_ptr, &c,
|
---|
| 3854 | PNG_BACKGROUND_GAMMA_SCREEN, 0/*need_expand*/,
|
---|
| 3855 | 0/*gamma: not used*/);
|
---|
| 3856 | }
|
---|
| 3857 |
|
---|
| 3858 | else /* compose on row: implemented below. */
|
---|
| 3859 | {
|
---|
| 3860 | do_local_compose = 1;
|
---|
| 3861 | /* This leaves the alpha channel in the output, so it has to be
|
---|
| 3862 | * removed by the code below. Set the encoding to the 'OPTIMIZE'
|
---|
| 3863 | * one so the code only has to hack on the pixels that require
|
---|
| 3864 | * composition.
|
---|
| 3865 | */
|
---|
| 3866 | mode = PNG_ALPHA_OPTIMIZED;
|
---|
| 3867 | }
|
---|
| 3868 | }
|
---|
| 3869 |
|
---|
| 3870 | else /* output needs an alpha channel */
|
---|
| 3871 | {
|
---|
| 3872 | /* This is tricky because it happens before the swap operation has
|
---|
| 3873 | * been accomplished; however, the swap does *not* swap the added
|
---|
| 3874 | * alpha channel (weird API), so it must be added in the correct
|
---|
| 3875 | * place.
|
---|
| 3876 | */
|
---|
| 3877 | png_uint_32 filler; /* opaque filler */
|
---|
| 3878 | int where;
|
---|
| 3879 |
|
---|
| 3880 | if (linear != 0)
|
---|
| 3881 | filler = 65535;
|
---|
| 3882 |
|
---|
| 3883 | else
|
---|
| 3884 | filler = 255;
|
---|
| 3885 |
|
---|
| 3886 | #ifdef PNG_FORMAT_AFIRST_SUPPORTED
|
---|
| 3887 | if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
|
---|
| 3888 | {
|
---|
| 3889 | where = PNG_FILLER_BEFORE;
|
---|
| 3890 | change &= ~PNG_FORMAT_FLAG_AFIRST;
|
---|
| 3891 | }
|
---|
| 3892 |
|
---|
| 3893 | else
|
---|
| 3894 | #endif
|
---|
| 3895 | where = PNG_FILLER_AFTER;
|
---|
| 3896 |
|
---|
| 3897 | png_set_add_alpha(png_ptr, filler, where);
|
---|
| 3898 | }
|
---|
| 3899 |
|
---|
| 3900 | /* This stops the (irrelevant) call to swap_alpha below. */
|
---|
| 3901 | change &= ~PNG_FORMAT_FLAG_ALPHA;
|
---|
| 3902 | }
|
---|
| 3903 |
|
---|
| 3904 | /* Now set the alpha mode correctly; this is always done, even if there is
|
---|
| 3905 | * no alpha channel in either the input or the output because it correctly
|
---|
| 3906 | * sets the output gamma.
|
---|
| 3907 | */
|
---|
| 3908 | png_set_alpha_mode_fixed(png_ptr, mode, output_gamma);
|
---|
| 3909 |
|
---|
| 3910 | # ifdef PNG_FORMAT_BGR_SUPPORTED
|
---|
| 3911 | if ((change & PNG_FORMAT_FLAG_BGR) != 0)
|
---|
| 3912 | {
|
---|
| 3913 | /* Check only the output format; PNG is never BGR; don't do this if
|
---|
| 3914 | * the output is gray, but fix up the 'format' value in that case.
|
---|
| 3915 | */
|
---|
| 3916 | if ((format & PNG_FORMAT_FLAG_COLOR) != 0)
|
---|
| 3917 | png_set_bgr(png_ptr);
|
---|
| 3918 |
|
---|
| 3919 | else
|
---|
| 3920 | format &= ~PNG_FORMAT_FLAG_BGR;
|
---|
| 3921 |
|
---|
| 3922 | change &= ~PNG_FORMAT_FLAG_BGR;
|
---|
| 3923 | }
|
---|
| 3924 | # endif
|
---|
| 3925 |
|
---|
| 3926 | # ifdef PNG_FORMAT_AFIRST_SUPPORTED
|
---|
| 3927 | if ((change & PNG_FORMAT_FLAG_AFIRST) != 0)
|
---|
| 3928 | {
|
---|
| 3929 | /* Only relevant if there is an alpha channel - it's particularly
|
---|
| 3930 | * important to handle this correctly because do_local_compose may
|
---|
| 3931 | * be set above and then libpng will keep the alpha channel for this
|
---|
| 3932 | * code to remove.
|
---|
| 3933 | */
|
---|
| 3934 | if ((format & PNG_FORMAT_FLAG_ALPHA) != 0)
|
---|
| 3935 | {
|
---|
| 3936 | /* Disable this if doing a local background,
|
---|
| 3937 | * TODO: remove this when local background is no longer required.
|
---|
| 3938 | */
|
---|
| 3939 | if (do_local_background != 2)
|
---|
| 3940 | png_set_swap_alpha(png_ptr);
|
---|
| 3941 | }
|
---|
| 3942 |
|
---|
| 3943 | else
|
---|
| 3944 | format &= ~PNG_FORMAT_FLAG_AFIRST;
|
---|
| 3945 |
|
---|
| 3946 | change &= ~PNG_FORMAT_FLAG_AFIRST;
|
---|
| 3947 | }
|
---|
| 3948 | # endif
|
---|
| 3949 |
|
---|
| 3950 | /* If the *output* is 16-bit then we need to check for a byte-swap on this
|
---|
| 3951 | * architecture.
|
---|
| 3952 | */
|
---|
| 3953 | if (linear != 0)
|
---|
| 3954 | {
|
---|
| 3955 | png_uint_16 le = 0x0001;
|
---|
| 3956 |
|
---|
| 3957 | if ((*(png_const_bytep) & le) != 0)
|
---|
| 3958 | png_set_swap(png_ptr);
|
---|
| 3959 | }
|
---|
| 3960 |
|
---|
| 3961 | /* If change is not now 0 some transformation is missing - error out. */
|
---|
| 3962 | if (change != 0)
|
---|
| 3963 | png_error(png_ptr, "png_read_image: unsupported transformation");
|
---|
| 3964 | }
|
---|
| 3965 |
|
---|
| 3966 | PNG_SKIP_CHUNKS(png_ptr);
|
---|
| 3967 |
|
---|
| 3968 | /* Update the 'info' structure and make sure the result is as required; first
|
---|
| 3969 | * make sure to turn on the interlace handling if it will be required
|
---|
| 3970 | * (because it can't be turned on *after* the call to png_read_update_info!)
|
---|
| 3971 | *
|
---|
| 3972 | * TODO: remove the do_local_background fixup below.
|
---|
| 3973 | */
|
---|
| 3974 | if (do_local_compose == 0 && do_local_background != 2)
|
---|
| 3975 | passes = png_set_interlace_handling(png_ptr);
|
---|
| 3976 |
|
---|
| 3977 | png_read_update_info(png_ptr, info_ptr);
|
---|
| 3978 |
|
---|
| 3979 | {
|
---|
| 3980 | png_uint_32 info_format = 0;
|
---|
| 3981 |
|
---|
| 3982 | if ((info_ptr->color_type & PNG_COLOR_MASK_COLOR) != 0)
|
---|
| 3983 | info_format |= PNG_FORMAT_FLAG_COLOR;
|
---|
| 3984 |
|
---|
| 3985 | if ((info_ptr->color_type & PNG_COLOR_MASK_ALPHA) != 0)
|
---|
| 3986 | {
|
---|
| 3987 | /* do_local_compose removes this channel below. */
|
---|
| 3988 | if (do_local_compose == 0)
|
---|
| 3989 | {
|
---|
| 3990 | /* do_local_background does the same if required. */
|
---|
| 3991 | if (do_local_background != 2 ||
|
---|
| 3992 | (format & PNG_FORMAT_FLAG_ALPHA) != 0)
|
---|
| 3993 | info_format |= PNG_FORMAT_FLAG_ALPHA;
|
---|
| 3994 | }
|
---|
| 3995 | }
|
---|
| 3996 |
|
---|
| 3997 | else if (do_local_compose != 0) /* internal error */
|
---|
| 3998 | png_error(png_ptr, "png_image_read: alpha channel lost");
|
---|
| 3999 |
|
---|
| 4000 | if ((format & PNG_FORMAT_FLAG_ASSOCIATED_ALPHA) != 0) {
|
---|
| 4001 | info_format |= PNG_FORMAT_FLAG_ASSOCIATED_ALPHA;
|
---|
| 4002 | }
|
---|
| 4003 |
|
---|
| 4004 | if (info_ptr->bit_depth == 16)
|
---|
| 4005 | info_format |= PNG_FORMAT_FLAG_LINEAR;
|
---|
| 4006 |
|
---|
| 4007 | #ifdef PNG_FORMAT_BGR_SUPPORTED
|
---|
| 4008 | if ((png_ptr->transformations & PNG_BGR) != 0)
|
---|
| 4009 | info_format |= PNG_FORMAT_FLAG_BGR;
|
---|
| 4010 | #endif
|
---|
| 4011 |
|
---|
| 4012 | #ifdef PNG_FORMAT_AFIRST_SUPPORTED
|
---|
| 4013 | if (do_local_background == 2)
|
---|
| 4014 | {
|
---|
| 4015 | if ((format & PNG_FORMAT_FLAG_AFIRST) != 0)
|
---|
| 4016 | info_format |= PNG_FORMAT_FLAG_AFIRST;
|
---|
| 4017 | }
|
---|
| 4018 |
|
---|
| 4019 | if ((png_ptr->transformations & PNG_SWAP_ALPHA) != 0 ||
|
---|
| 4020 | ((png_ptr->transformations & PNG_ADD_ALPHA) != 0 &&
|
---|
| 4021 | (png_ptr->flags & PNG_FLAG_FILLER_AFTER) == 0))
|
---|
| 4022 | {
|
---|
| 4023 | if (do_local_background == 2)
|
---|
| 4024 | png_error(png_ptr, "unexpected alpha swap transformation");
|
---|
| 4025 |
|
---|
| 4026 | info_format |= PNG_FORMAT_FLAG_AFIRST;
|
---|
| 4027 | }
|
---|
| 4028 | # endif
|
---|
| 4029 |
|
---|
| 4030 | /* This is actually an internal error. */
|
---|
| 4031 | if (info_format != format)
|
---|
| 4032 | png_error(png_ptr, "png_read_image: invalid transformations");
|
---|
| 4033 | }
|
---|
| 4034 |
|
---|
| 4035 | /* Now read the rows. If do_local_compose is set then it is necessary to use
|
---|
| 4036 | * a local row buffer. The output will be GA, RGBA or BGRA and must be
|
---|
| 4037 | * converted to G, RGB or BGR as appropriate. The 'local_row' member of the
|
---|
| 4038 | * display acts as a flag.
|
---|
| 4039 | */
|
---|
| 4040 | {
|
---|
| 4041 | png_voidp first_row = display->buffer;
|
---|
| 4042 | ptrdiff_t row_bytes = display->row_stride;
|
---|
| 4043 |
|
---|
| 4044 | if (linear != 0)
|
---|
| 4045 | row_bytes *= 2;
|
---|
| 4046 |
|
---|
| 4047 | /* The following expression is designed to work correctly whether it gives
|
---|
| 4048 | * a signed or an unsigned result.
|
---|
| 4049 | */
|
---|
| 4050 | if (row_bytes < 0)
|
---|
| 4051 | {
|
---|
| 4052 | char *ptr = png_voidcast(char*, first_row);
|
---|
| 4053 | ptr += (image->height-1) * (-row_bytes);
|
---|
| 4054 | first_row = png_voidcast(png_voidp, ptr);
|
---|
| 4055 | }
|
---|
| 4056 |
|
---|
| 4057 | display->first_row = first_row;
|
---|
| 4058 | display->row_bytes = row_bytes;
|
---|
| 4059 | }
|
---|
| 4060 |
|
---|
| 4061 | if (do_local_compose != 0)
|
---|
| 4062 | {
|
---|
| 4063 | int result;
|
---|
| 4064 | png_voidp row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr));
|
---|
| 4065 |
|
---|
| 4066 | display->local_row = row;
|
---|
| 4067 | result = png_safe_execute(image, png_image_read_composite, display);
|
---|
| 4068 | display->local_row = NULL;
|
---|
| 4069 | png_free(png_ptr, row);
|
---|
| 4070 |
|
---|
| 4071 | return result;
|
---|
| 4072 | }
|
---|
| 4073 |
|
---|
| 4074 | else if (do_local_background == 2)
|
---|
| 4075 | {
|
---|
| 4076 | int result;
|
---|
| 4077 | png_voidp row = png_malloc(png_ptr, png_get_rowbytes(png_ptr, info_ptr));
|
---|
| 4078 |
|
---|
| 4079 | display->local_row = row;
|
---|
| 4080 | result = png_safe_execute(image, png_image_read_background, display);
|
---|
| 4081 | display->local_row = NULL;
|
---|
| 4082 | png_free(png_ptr, row);
|
---|
| 4083 |
|
---|
| 4084 | return result;
|
---|
| 4085 | }
|
---|
| 4086 |
|
---|
| 4087 | else
|
---|
| 4088 | {
|
---|
| 4089 | png_alloc_size_t row_bytes = (png_alloc_size_t)display->row_bytes;
|
---|
| 4090 |
|
---|
| 4091 | while (--passes >= 0)
|
---|
| 4092 | {
|
---|
| 4093 | png_uint_32 y = image->height;
|
---|
| 4094 | png_bytep row = png_voidcast(png_bytep, display->first_row);
|
---|
| 4095 |
|
---|
| 4096 | for (; y > 0; --y)
|
---|
| 4097 | {
|
---|
| 4098 | png_read_row(png_ptr, row, NULL);
|
---|
| 4099 | row += row_bytes;
|
---|
| 4100 | }
|
---|
| 4101 | }
|
---|
| 4102 |
|
---|
| 4103 | return 1;
|
---|
| 4104 | }
|
---|
| 4105 | }
|
---|
| 4106 |
|
---|
| 4107 | int PNGAPI
|
---|
| 4108 | png_image_finish_read(png_imagep image, png_const_colorp background,
|
---|
| 4109 | void *buffer, png_int_32 row_stride, void *colormap)
|
---|
| 4110 | {
|
---|
| 4111 | if (image != NULL && image->version == PNG_IMAGE_VERSION)
|
---|
| 4112 | {
|
---|
| 4113 | /* Check for row_stride overflow. This check is not performed on the
|
---|
| 4114 | * original PNG format because it may not occur in the output PNG format
|
---|
| 4115 | * and libpng deals with the issues of reading the original.
|
---|
| 4116 | */
|
---|
| 4117 | unsigned int channels = PNG_IMAGE_PIXEL_CHANNELS(image->format);
|
---|
| 4118 |
|
---|
| 4119 | /* The following checks just the 'row_stride' calculation to ensure it
|
---|
| 4120 | * fits in a signed 32-bit value. Because channels/components can be
|
---|
| 4121 | * either 1 or 2 bytes in size the length of a row can still overflow 32
|
---|
| 4122 | * bits; this is just to verify that the 'row_stride' argument can be
|
---|
| 4123 | * represented.
|
---|
| 4124 | */
|
---|
| 4125 | if (image->width <= 0x7fffffffU/channels) /* no overflow */
|
---|
| 4126 | {
|
---|
| 4127 | png_uint_32 check;
|
---|
| 4128 | png_uint_32 png_row_stride = image->width * channels;
|
---|
| 4129 |
|
---|
| 4130 | if (row_stride == 0)
|
---|
| 4131 | row_stride = (png_int_32)/*SAFE*/png_row_stride;
|
---|
| 4132 |
|
---|
| 4133 | if (row_stride < 0)
|
---|
| 4134 | check = (png_uint_32)(-row_stride);
|
---|
| 4135 |
|
---|
| 4136 | else
|
---|
| 4137 | check = (png_uint_32)row_stride;
|
---|
| 4138 |
|
---|
| 4139 | /* This verifies 'check', the absolute value of the actual stride
|
---|
| 4140 | * passed in and detects overflow in the application calculation (i.e.
|
---|
| 4141 | * if the app did actually pass in a non-zero 'row_stride'.
|
---|
| 4142 | */
|
---|
| 4143 | if (image->opaque != NULL && buffer != NULL && check >= png_row_stride)
|
---|
| 4144 | {
|
---|
| 4145 | /* Now check for overflow of the image buffer calculation; this
|
---|
| 4146 | * limits the whole image size to 32 bits for API compatibility with
|
---|
| 4147 | * the current, 32-bit, PNG_IMAGE_BUFFER_SIZE macro.
|
---|
| 4148 | *
|
---|
| 4149 | * The PNG_IMAGE_BUFFER_SIZE macro is:
|
---|
| 4150 | *
|
---|
| 4151 | * (PNG_IMAGE_PIXEL_COMPONENT_SIZE(fmt)*height*(row_stride))
|
---|
| 4152 | *
|
---|
| 4153 | * And the component size is always 1 or 2, so make sure that the
|
---|
| 4154 | * number of *bytes* that the application is saying are available
|
---|
| 4155 | * does actually fit into a 32-bit number.
|
---|
| 4156 | *
|
---|
| 4157 | * NOTE: this will be changed in 1.7 because PNG_IMAGE_BUFFER_SIZE
|
---|
| 4158 | * will be changed to use png_alloc_size_t; bigger images can be
|
---|
| 4159 | * accommodated on 64-bit systems.
|
---|
| 4160 | */
|
---|
| 4161 | if (image->height <=
|
---|
| 4162 | 0xffffffffU/PNG_IMAGE_PIXEL_COMPONENT_SIZE(image->format)/check)
|
---|
| 4163 | {
|
---|
| 4164 | if ((image->format & PNG_FORMAT_FLAG_COLORMAP) == 0 ||
|
---|
| 4165 | (image->colormap_entries > 0 && colormap != NULL))
|
---|
| 4166 | {
|
---|
| 4167 | int result;
|
---|
| 4168 | png_image_read_control display;
|
---|
| 4169 |
|
---|
| 4170 | memset(&display, 0, (sizeof display));
|
---|
| 4171 | display.image = image;
|
---|
| 4172 | display.buffer = buffer;
|
---|
| 4173 | display.row_stride = row_stride;
|
---|
| 4174 | display.colormap = colormap;
|
---|
| 4175 | display.background = background;
|
---|
| 4176 | display.local_row = NULL;
|
---|
| 4177 |
|
---|
| 4178 | /* Choose the correct 'end' routine; for the color-map case
|
---|
| 4179 | * all the setup has already been done.
|
---|
| 4180 | */
|
---|
| 4181 | if ((image->format & PNG_FORMAT_FLAG_COLORMAP) != 0)
|
---|
| 4182 | result =
|
---|
| 4183 | png_safe_execute(image,
|
---|
| 4184 | png_image_read_colormap, &display) &&
|
---|
| 4185 | png_safe_execute(image,
|
---|
| 4186 | png_image_read_colormapped, &display);
|
---|
| 4187 |
|
---|
| 4188 | else
|
---|
| 4189 | result =
|
---|
| 4190 | png_safe_execute(image,
|
---|
| 4191 | png_image_read_direct, &display);
|
---|
| 4192 |
|
---|
| 4193 | png_image_free(image);
|
---|
| 4194 | return result;
|
---|
| 4195 | }
|
---|
| 4196 |
|
---|
| 4197 | else
|
---|
| 4198 | return png_image_error(image,
|
---|
| 4199 | "png_image_finish_read[color-map]: no color-map");
|
---|
| 4200 | }
|
---|
| 4201 |
|
---|
| 4202 | else
|
---|
| 4203 | return png_image_error(image,
|
---|
| 4204 | "png_image_finish_read: image too large");
|
---|
| 4205 | }
|
---|
| 4206 |
|
---|
| 4207 | else
|
---|
| 4208 | return png_image_error(image,
|
---|
| 4209 | "png_image_finish_read: invalid argument");
|
---|
| 4210 | }
|
---|
| 4211 |
|
---|
| 4212 | else
|
---|
| 4213 | return png_image_error(image,
|
---|
| 4214 | "png_image_finish_read: row_stride too large");
|
---|
| 4215 | }
|
---|
| 4216 |
|
---|
| 4217 | else if (image != NULL)
|
---|
| 4218 | return png_image_error(image,
|
---|
| 4219 | "png_image_finish_read: damaged PNG_IMAGE_VERSION");
|
---|
| 4220 |
|
---|
| 4221 | return 0;
|
---|
| 4222 | }
|
---|
| 4223 |
|
---|
| 4224 | #endif /* SIMPLIFIED_READ */
|
---|
| 4225 | #endif /* READ */
|
---|