source/libs/libpng/libpng-1.6.16/pngstruct.h

   1
   2 /* pngstruct.h - header file for PNG reference library
   3  *
   4  * Copyright (c) 1998-2013 Glenn Randers-Pehrson
   5  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
   6  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
   7  *
   8  * Last changed in libpng 1.6.1 [March 28, 2013]
   9  *
  10  * This code is released under the libpng license.
  11  * For conditions of distribution and use, see the disclaimer
  12  * and license in png.h
  13  */
  14
  15 /* The structure that holds the information to read and write PNG files.
  16  * The only people who need to care about what is inside of this are the
  17  * people who will be modifying the library for their own special needs.
  18  * It should NOT be accessed directly by an application.
  19  */
  20
  21 #ifndef PNGSTRUCT_H
  22 #define PNGSTRUCT_H
  23 /* zlib.h defines the structure z_stream, an instance of which is included
  24  * in this structure and is required for decompressing the LZ compressed
  25  * data in PNG files.
  26  */
  27 #ifndef ZLIB_CONST
  28    /* We must ensure that zlib uses 'const' in declarations. */
  29 #  define ZLIB_CONST
  30 #endif
  31 #include "zlib.h"
  32 #ifdef const
  33    /* zlib.h sometimes #defines const to nothing, undo this. */
  34 #  undef const
  35 #endif
  36
  37 /* zlib.h has mediocre z_const use before 1.2.6, this stuff is for compatibility
  38  * with older builds.
  39  */
  40 #if ZLIB_VERNUM < 0x1260
  41 #  define PNGZ_MSG_CAST(s) png_constcast(char*,s)
  42 #  define PNGZ_INPUT_CAST(b) png_constcast(png_bytep,b)
  43 #else
  44 #  define PNGZ_MSG_CAST(s) (s)
  45 #  define PNGZ_INPUT_CAST(b) (b)
  46 #endif
  47
  48 /* zlib.h declares a magic type 'uInt' that limits the amount of data that zlib
  49  * can handle at once.  This type need be no larger than 16 bits (so maximum of
  50  * 65535), this define allows us to discover how big it is, but limited by the
  51  * maximuum for png_size_t.  The value can be overriden in a library build
  52  * (pngusr.h, or set it in CPPFLAGS) and it works to set it to a considerably
  53  * lower value (e.g. 255 works).  A lower value may help memory usage (slightly)
  54  * and may even improve performance on some systems (and degrade it on others.)
  55  */
  56 #ifndef ZLIB_IO_MAX
  57 #  define ZLIB_IO_MAX ((uInt)-1)
  58 #endif
  59
  60 #ifdef PNG_WRITE_SUPPORTED
  61 /* The type of a compression buffer list used by the write code. */
  62 typedef struct png_compression_buffer
  63 {
  64    struct png_compression_buffer *next;
  65    png_byte                       output[1]; /* actually zbuf_size */
  66 } png_compression_buffer, *png_compression_bufferp;
  67
  68 #define PNG_COMPRESSION_BUFFER_SIZE(pp)\
  69    (offsetof(png_compression_buffer, output) + (pp)->zbuffer_size)
  70 #endif
  71
  72 /* Colorspace support; structures used in png_struct, png_info and in internal
  73  * functions to hold and communicate information about the color space.
  74  *
  75  * PNG_COLORSPACE_SUPPORTED is only required if the application will perform
  76  * colorspace corrections, otherwise all the colorspace information can be
  77  * skipped and the size of libpng can be reduced (significantly) by compiling
  78  * out the colorspace support.
  79  */
  80 #ifdef PNG_COLORSPACE_SUPPORTED
  81 /* The chromaticities of the red, green and blue colorants and the chromaticity
  82  * of the corresponding white point (i.e. of rgb(1.0,1.0,1.0)).
  83  */
  84 typedef struct png_xy
  85 {
  86    png_fixed_point redx, redy;
  87    png_fixed_point greenx, greeny;
  88    png_fixed_point bluex, bluey;
  89    png_fixed_point whitex, whitey;
  90 } png_xy;
  91
  92 /* The same data as above but encoded as CIE XYZ values.  When this data comes
  93  * from chromaticities the sum of the Y values is assumed to be 1.0
  94  */
  95 typedef struct png_XYZ
  96 {
  97    png_fixed_point red_X, red_Y, red_Z;
  98    png_fixed_point green_X, green_Y, green_Z;
  99    png_fixed_point blue_X, blue_Y, blue_Z;
 100 } png_XYZ;
 101 #endif /* COLORSPACE */
 102
 103 #if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
 104 /* A colorspace is all the above plus, potentially, profile information,
 105  * however at present libpng does not use the profile internally so it is only
 106  * stored in the png_info struct (if iCCP is supported.)  The rendering intent
 107  * is retained here and is checked.
 108  *
 109  * The file gamma encoding information is also stored here and gamma correction
 110  * is done by libpng, whereas color correction must currently be done by the
 111  * application.
 112  */
 113 typedef struct png_colorspace
 114 {
 115 #ifdef PNG_GAMMA_SUPPORTED
 116    png_fixed_point gamma;        /* File gamma */
 117 #endif
 118
 119 #ifdef PNG_COLORSPACE_SUPPORTED
 120    png_xy      end_points_xy;    /* End points as chromaticities */
 121    png_XYZ     end_points_XYZ;   /* End points as CIE XYZ colorant values */
 122    png_uint_16 rendering_intent; /* Rendering intent of a profile */
 123 #endif
 124
 125    /* Flags are always defined to simplify the code. */
 126    png_uint_16 flags;            /* As defined below */
 127 } png_colorspace, * PNG_RESTRICT png_colorspacerp;
 128
 129 typedef const png_colorspace * PNG_RESTRICT png_const_colorspacerp;
 130
 131 /* General flags for the 'flags' field */
 132 #define PNG_COLORSPACE_HAVE_GAMMA           0x0001
 133 #define PNG_COLORSPACE_HAVE_ENDPOINTS       0x0002
 134 #define PNG_COLORSPACE_HAVE_INTENT          0x0004
 135 #define PNG_COLORSPACE_FROM_gAMA            0x0008
 136 #define PNG_COLORSPACE_FROM_cHRM            0x0010
 137 #define PNG_COLORSPACE_FROM_sRGB            0x0020
 138 #define PNG_COLORSPACE_ENDPOINTS_MATCH_sRGB 0x0040
 139 #define PNG_COLORSPACE_MATCHES_sRGB         0x0080 /* exact match on profile */
 140 #define PNG_COLORSPACE_INVALID              0x8000
 141 #define PNG_COLORSPACE_CANCEL(flags)        (0xffff ^ (flags))
 142 #endif /* COLORSPACE || GAMMA */
 143
 144 struct png_struct_def
 145 {
 146 #ifdef PNG_SETJMP_SUPPORTED
 147    jmp_buf jmp_buf_local;     /* New name in 1.6.0 for jmp_buf in png_struct */
 148    png_longjmp_ptr longjmp_fn;/* setjmp non-local goto function. */
 149    jmp_buf *jmp_buf_ptr;      /* passed to longjmp_fn */
 150    size_t jmp_buf_size;       /* size of the above, if allocated */
 151 #endif
 152    png_error_ptr error_fn;    /* function for printing errors and aborting */
 153 #ifdef PNG_WARNINGS_SUPPORTED
 154    png_error_ptr warning_fn;  /* function for printing warnings */
 155 #endif
 156    png_voidp error_ptr;       /* user supplied struct for error functions */
 157    png_rw_ptr write_data_fn;  /* function for writing output data */
 158    png_rw_ptr read_data_fn;   /* function for reading input data */
 159    png_voidp io_ptr;          /* ptr to application struct for I/O functions */
 160
 161 #ifdef PNG_READ_USER_TRANSFORM_SUPPORTED
 162    png_user_transform_ptr read_user_transform_fn; /* user read transform */
 163 #endif
 164
 165 #ifdef PNG_WRITE_USER_TRANSFORM_SUPPORTED
 166    png_user_transform_ptr write_user_transform_fn; /* user write transform */
 167 #endif
 168
 169 /* These were added in libpng-1.0.2 */
 170 #ifdef PNG_USER_TRANSFORM_PTR_SUPPORTED
 171 #if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
 172     defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
 173    png_voidp user_transform_ptr; /* user supplied struct for user transform */
 174    png_byte user_transform_depth;    /* bit depth of user transformed pixels */
 175    png_byte user_transform_channels; /* channels in user transformed pixels */
 176 #endif
 177 #endif
 178
 179    png_uint_32 mode;          /* tells us where we are in the PNG file */
 180    png_uint_32 flags;         /* flags indicating various things to libpng */
 181    png_uint_32 transformations; /* which transformations to perform */
 182
 183    png_uint_32 zowner;        /* ID (chunk type) of zstream owner, 0 if none */
 184    z_stream    zstream;       /* decompression structure */
 185
 186 #ifdef PNG_WRITE_SUPPORTED
 187    png_compression_bufferp zbuffer_list; /* Created on demand during write */
 188    uInt                    zbuffer_size; /* size of the actual buffer */
 189
 190    int zlib_level;            /* holds zlib compression level */
 191    int zlib_method;           /* holds zlib compression method */
 192    int zlib_window_bits;      /* holds zlib compression window bits */
 193    int zlib_mem_level;        /* holds zlib compression memory level */
 194    int zlib_strategy;         /* holds zlib compression strategy */
 195 #endif
 196 /* Added at libpng 1.5.4 */
 197 #ifdef PNG_WRITE_CUSTOMIZE_ZTXT_COMPRESSION_SUPPORTED
 198    int zlib_text_level;            /* holds zlib compression level */
 199    int zlib_text_method;           /* holds zlib compression method */
 200    int zlib_text_window_bits;      /* holds zlib compression window bits */
 201    int zlib_text_mem_level;        /* holds zlib compression memory level */
 202    int zlib_text_strategy;         /* holds zlib compression strategy */
 203 #endif
 204 /* End of material added at libpng 1.5.4 */
 205 /* Added at libpng 1.6.0 */
 206 #ifdef PNG_WRITE_SUPPORTED
 207    int zlib_set_level;        /* Actual values set into the zstream on write */
 208    int zlib_set_method;
 209    int zlib_set_window_bits;
 210    int zlib_set_mem_level;
 211    int zlib_set_strategy;
 212 #endif
 213
 214    png_uint_32 width;         /* width of image in pixels */
 215    png_uint_32 height;        /* height of image in pixels */
 216    png_uint_32 num_rows;      /* number of rows in current pass */
 217    png_uint_32 usr_width;     /* width of row at start of write */
 218    png_size_t rowbytes;       /* size of row in bytes */
 219    png_uint_32 iwidth;        /* width of current interlaced row in pixels */
 220    png_uint_32 row_number;    /* current row in interlace pass */
 221    png_uint_32 chunk_name;    /* PNG_CHUNK() id of current chunk */
 222    png_bytep prev_row;        /* buffer to save previous (unfiltered) row.
 223                                * This is a pointer into big_prev_row
 224                                */
 225    png_bytep row_buf;         /* buffer to save current (unfiltered) row.
 226                                * This is a pointer into big_row_buf
 227                                */
 228 #ifdef PNG_WRITE_SUPPORTED
 229    png_bytep sub_row;         /* buffer to save "sub" row when filtering */
 230    png_bytep up_row;          /* buffer to save "up" row when filtering */
 231    png_bytep avg_row;         /* buffer to save "avg" row when filtering */
 232    png_bytep paeth_row;       /* buffer to save "Paeth" row when filtering */
 233 #endif
 234    png_size_t info_rowbytes;  /* Added in 1.5.4: cache of updated row bytes */
 235
 236    png_uint_32 idat_size;     /* current IDAT size for read */
 237    png_uint_32 crc;           /* current chunk CRC value */
 238    png_colorp palette;        /* palette from the input file */
 239    png_uint_16 num_palette;   /* number of color entries in palette */
 240
 241 /* Added at libpng-1.5.10 */
 242 #ifdef PNG_CHECK_FOR_INVALID_INDEX_SUPPORTED
 243    int num_palette_max;       /* maximum palette index found in IDAT */
 244 #endif
 245
 246    png_uint_16 num_trans;     /* number of transparency values */
 247    png_byte compression;      /* file compression type (always 0) */
 248    png_byte filter;           /* file filter type (always 0) */
 249    png_byte interlaced;       /* PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
 250    png_byte pass;             /* current interlace pass (0 - 6) */
 251    png_byte do_filter;        /* row filter flags (see PNG_FILTER_ below ) */
 252    png_byte color_type;       /* color type of file */
 253    png_byte bit_depth;        /* bit depth of file */
 254    png_byte usr_bit_depth;    /* bit depth of users row: write only */
 255    png_byte pixel_depth;      /* number of bits per pixel */
 256    png_byte channels;         /* number of channels in file */
 257 #ifdef PNG_WRITE_SUPPORTED
 258    png_byte usr_channels;     /* channels at start of write: write only */
 259 #endif
 260    png_byte sig_bytes;        /* magic bytes read/written from start of file */
 261    png_byte maximum_pixel_depth;
 262                               /* pixel depth used for the row buffers */
 263    png_byte transformed_pixel_depth;
 264                               /* pixel depth after read/write transforms */
 265 #if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
 266    png_uint_16 filler;           /* filler bytes for pixel expansion */
 267 #endif
 268
 269 #if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) ||\
 270    defined(PNG_READ_ALPHA_MODE_SUPPORTED)
 271    png_byte background_gamma_type;
 272    png_fixed_point background_gamma;
 273    png_color_16 background;   /* background color in screen gamma space */
 274 #ifdef PNG_READ_GAMMA_SUPPORTED
 275    png_color_16 background_1; /* background normalized to gamma 1.0 */
 276 #endif
 277 #endif /* bKGD */
 278
 279 #ifdef PNG_WRITE_FLUSH_SUPPORTED
 280    png_flush_ptr output_flush_fn; /* Function for flushing output */
 281    png_uint_32 flush_dist;    /* how many rows apart to flush, 0 - no flush */
 282    png_uint_32 flush_rows;    /* number of rows written since last flush */
 283 #endif
 284
 285 #ifdef PNG_READ_GAMMA_SUPPORTED
 286    int gamma_shift;      /* number of "insignificant" bits in 16-bit gamma */
 287    png_fixed_point screen_gamma; /* screen gamma value (display_exponent) */
 288
 289    png_bytep gamma_table;     /* gamma table for 8-bit depth files */
 290    png_uint_16pp gamma_16_table; /* gamma table for 16-bit depth files */
 291 #if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
 292    defined(PNG_READ_ALPHA_MODE_SUPPORTED) || \
 293    defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
 294    png_bytep gamma_from_1;    /* converts from 1.0 to screen */
 295    png_bytep gamma_to_1;      /* converts from file to 1.0 */
 296    png_uint_16pp gamma_16_from_1; /* converts from 1.0 to screen */
 297    png_uint_16pp gamma_16_to_1; /* converts from file to 1.0 */
 298 #endif /* READ_BACKGROUND || READ_ALPHA_MODE || RGB_TO_GRAY */
 299 #endif
 300
 301 #if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_sBIT_SUPPORTED)
 302    png_color_8 sig_bit;       /* significant bits in each available channel */
 303 #endif
 304
 305 #if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
 306    png_color_8 shift;         /* shift for significant bit tranformation */
 307 #endif
 308
 309 #if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) \
 310  || defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
 311    png_bytep trans_alpha;           /* alpha values for paletted files */
 312    png_color_16 trans_color;  /* transparent color for non-paletted files */
 313 #endif
 314
 315    png_read_status_ptr read_row_fn;   /* called after each row is decoded */
 316    png_write_status_ptr write_row_fn; /* called after each row is encoded */
 317 #ifdef PNG_PROGRESSIVE_READ_SUPPORTED
 318    png_progressive_info_ptr info_fn; /* called after header data fully read */
 319    png_progressive_row_ptr row_fn;   /* called after a prog. row is decoded */
 320    png_progressive_end_ptr end_fn;   /* called after image is complete */
 321    png_bytep save_buffer_ptr;        /* current location in save_buffer */
 322    png_bytep save_buffer;            /* buffer for previously read data */
 323    png_bytep current_buffer_ptr;     /* current location in current_buffer */
 324    png_bytep current_buffer;         /* buffer for recently used data */
 325    png_uint_32 push_length;          /* size of current input chunk */
 326    png_uint_32 skip_length;          /* bytes to skip in input data */
 327    png_size_t save_buffer_size;      /* amount of data now in save_buffer */
 328    png_size_t save_buffer_max;       /* total size of save_buffer */
 329    png_size_t buffer_size;           /* total amount of available input data */
 330    png_size_t current_buffer_size;   /* amount of data now in current_buffer */
 331    int process_mode;                 /* what push library is currently doing */
 332    int cur_palette;                  /* current push library palette index */
 333
 334 #endif /* PROGRESSIVE_READ */
 335
 336 #if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
 337 /* For the Borland special 64K segment handler */
 338    png_bytepp offset_table_ptr;
 339    png_bytep offset_table;
 340    png_uint_16 offset_table_number;
 341    png_uint_16 offset_table_count;
 342    png_uint_16 offset_table_count_free;
 343 #endif
 344
 345 #ifdef PNG_READ_QUANTIZE_SUPPORTED
 346    png_bytep palette_lookup; /* lookup table for quantizing */
 347    png_bytep quantize_index; /* index translation for palette files */
 348 #endif
 349
 350 #ifdef PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
 351    png_byte heuristic_method;        /* heuristic for row filter selection */
 352    png_byte num_prev_filters;        /* number of weights for previous rows */
 353    png_bytep prev_filters;           /* filter type(s) of previous row(s) */
 354    png_uint_16p filter_weights;      /* weight(s) for previous line(s) */
 355    png_uint_16p inv_filter_weights;  /* 1/weight(s) for previous line(s) */
 356    png_uint_16p filter_costs;        /* relative filter calculation cost */
 357    png_uint_16p inv_filter_costs;    /* 1/relative filter calculation cost */
 358 #endif
 359
 360    /* Options */
 361 #ifdef PNG_SET_OPTION_SUPPORTED
 362    png_byte options;           /* On/off state (up to 4 options) */
 363 #endif
 364
 365 #if PNG_LIBPNG_VER < 10700
 366 /* To do: remove this from libpng-1.7 */
 367 #ifdef PNG_TIME_RFC1123_SUPPORTED
 368    char time_buffer[29]; /* String to hold RFC 1123 time text */
 369 #endif
 370 #endif
 371
 372 /* New members added in libpng-1.0.6 */
 373
 374    png_uint_32 free_me;    /* flags items libpng is responsible for freeing */
 375
 376 #ifdef PNG_USER_CHUNKS_SUPPORTED
 377    png_voidp user_chunk_ptr;
 378 #ifdef PNG_READ_USER_CHUNKS_SUPPORTED
 379    png_user_chunk_ptr read_user_chunk_fn; /* user read chunk handler */
 380 #endif
 381 #endif
 382
 383 #ifdef PNG_SET_UNKNOWN_CHUNKS_SUPPORTED
 384    int          unknown_default; /* As PNG_HANDLE_* */
 385    unsigned int num_chunk_list;  /* Number of entries in the list */
 386    png_bytep    chunk_list;      /* List of png_byte[5]; the textual chunk name
 387                                   * followed by a PNG_HANDLE_* byte */
 388 #endif
 389
 390 /* New members added in libpng-1.0.3 */
 391 #ifdef PNG_READ_RGB_TO_GRAY_SUPPORTED
 392    png_byte rgb_to_gray_status;
 393    /* Added in libpng 1.5.5 to record setting of coefficients: */
 394    png_byte rgb_to_gray_coefficients_set;
 395    /* These were changed from png_byte in libpng-1.0.6 */
 396    png_uint_16 rgb_to_gray_red_coeff;
 397    png_uint_16 rgb_to_gray_green_coeff;
 398    /* deleted in 1.5.5: rgb_to_gray_blue_coeff; */
 399 #endif
 400
 401 /* New member added in libpng-1.0.4 (renamed in 1.0.9) */
 402 #if defined(PNG_MNG_FEATURES_SUPPORTED)
 403 /* Changed from png_byte to png_uint_32 at version 1.2.0 */
 404    png_uint_32 mng_features_permitted;
 405 #endif
 406
 407 /* New member added in libpng-1.0.9, ifdef'ed out in 1.0.12, enabled in 1.2.0 */
 408 #ifdef PNG_MNG_FEATURES_SUPPORTED
 409    png_byte filter_type;
 410 #endif
 411
 412 /* New members added in libpng-1.2.0 */
 413
 414 /* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */
 415 #ifdef PNG_USER_MEM_SUPPORTED
 416    png_voidp mem_ptr;             /* user supplied struct for mem functions */
 417    png_malloc_ptr malloc_fn;      /* function for allocating memory */
 418    png_free_ptr free_fn;          /* function for freeing memory */
 419 #endif
 420
 421 /* New member added in libpng-1.0.13 and 1.2.0 */
 422    png_bytep big_row_buf;         /* buffer to save current (unfiltered) row */
 423
 424 #ifdef PNG_READ_QUANTIZE_SUPPORTED
 425 /* The following three members were added at version 1.0.14 and 1.2.4 */
 426    png_bytep quantize_sort;          /* working sort array */
 427    png_bytep index_to_palette;       /* where the original index currently is
 428                                         in the palette */
 429    png_bytep palette_to_index;       /* which original index points to this
 430                                          palette color */
 431 #endif
 432
 433 /* New members added in libpng-1.0.16 and 1.2.6 */
 434    png_byte compression_type;
 435
 436 #ifdef PNG_USER_LIMITS_SUPPORTED
 437    png_uint_32 user_width_max;
 438    png_uint_32 user_height_max;
 439
 440    /* Added in libpng-1.4.0: Total number of sPLT, text, and unknown
 441     * chunks that can be stored (0 means unlimited).
 442     */
 443    png_uint_32 user_chunk_cache_max;
 444
 445    /* Total memory that a zTXt, sPLT, iTXt, iCCP, or unknown chunk
 446     * can occupy when decompressed.  0 means unlimited.
 447     */
 448    png_alloc_size_t user_chunk_malloc_max;
 449 #endif
 450
 451 /* New member added in libpng-1.0.25 and 1.2.17 */
 452 #ifdef PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
 453    /* Temporary storage for unknown chunk that the library doesn't recognize,
 454     * used while reading the chunk.
 455     */
 456    png_unknown_chunk unknown_chunk;
 457 #endif
 458
 459 /* New member added in libpng-1.2.26 */
 460   png_size_t old_big_row_buf_size;
 461
 462 #ifdef PNG_READ_SUPPORTED
 463 /* New member added in libpng-1.2.30 */
 464   png_bytep        read_buffer;      /* buffer for reading chunk data */
 465   png_alloc_size_t read_buffer_size; /* current size of the buffer */
 466 #endif
 467 #ifdef PNG_SEQUENTIAL_READ_SUPPORTED
 468   uInt             IDAT_read_size;   /* limit on read buffer size for IDAT */
 469 #endif
 470
 471 #ifdef PNG_IO_STATE_SUPPORTED
 472 /* New member added in libpng-1.4.0 */
 473    png_uint_32 io_state;
 474 #endif
 475
 476 /* New member added in libpng-1.5.6 */
 477    png_bytep big_prev_row;
 478
 479 /* New member added in libpng-1.5.7 */
 480    void (*read_filter[PNG_FILTER_VALUE_LAST-1])(png_row_infop row_info,
 481       png_bytep row, png_const_bytep prev_row);
 482
 483 #ifdef PNG_READ_SUPPORTED
 484 #if defined(PNG_COLORSPACE_SUPPORTED) || defined(PNG_GAMMA_SUPPORTED)
 485    png_colorspace   colorspace;
 486 #endif
 487 #endif
 488 };
 489 #endif /* PNGSTRUCT_H */