/thirdparty/libpng/png.h

/* png.h - header file for PNG reference library

 *

 * libpng version 1.2.7 - September 12, 2004

 * Copyright (c) 1998-2004 Glenn Randers-Pehrson

 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)

 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)

 *

 * Authors and maintainers:

 *  libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat

 *  libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger

 *  libpng versions 0.97, January 1998, through 1.2.7 - September 12, 2004: Glenn

 *  See also "Contributing Authors", below.

 *

 * Note about libpng version numbers:

 *

 *    Due to various miscommunications, unforeseen code incompatibilities

 *    and occasional factors outside the authors' control, version numbering

 *    on the library has not always been consistent and straightforward.

 *    The following table summarizes matters since version 0.89c, which was

 *    the first widely used release:

 *

 *    source                 png.h  png.h  shared-lib

 *    version                string   int  version

 *    -------                ------ -----  ----------

 *    0.89c "1.0 beta 3"     0.89      89  1.0.89

 *    0.90  "1.0 beta 4"     0.90      90  0.90  [should have been 2.0.90]

 *    0.95  "1.0 beta 5"     0.95      95  0.95  [should have been 2.0.95]

 *    0.96  "1.0 beta 6"     0.96      96  0.96  [should have been 2.0.96]

 *    0.97b "1.00.97 beta 7" 1.00.97   97  1.0.1 [should have been 2.0.97]

 *    0.97c                  0.97      97  2.0.97

 *    0.98                   0.98      98  2.0.98

 *    0.99                   0.99      98  2.0.99

 *    0.99a-m                0.99      99  2.0.99

 *    1.00                   1.00     100  2.1.0 [100 should be 10000]

 *    1.0.0      (from here on, the   100  2.1.0 [100 should be 10000]

 *    1.0.1       png.h string is   10001  2.1.0

 *    1.0.1a-e    identical to the  10002  from here on, the shared library

 *    1.0.2       source version)   10002  is 2.V where V is the source code

 *    1.0.2a-b                      10003  version, except as noted.

 *    1.0.3                         10003

 *    1.0.3a-d                      10004

 *    1.0.4                         10004

 *    1.0.4a-f                      10005

 *    1.0.5 (+ 2 patches)           10005

 *    1.0.5a-d                      10006

 *    1.0.5e-r                      10100 (not source compatible)

 *    1.0.5s-v                      10006 (not binary compatible)

 *    1.0.6 (+ 3 patches)           10006 (still binary incompatible)

 *    1.0.6d-f                      10007 (still binary incompatible)

 *    1.0.6g                        10007

 *    1.0.6h                        10007  10.6h (testing xy.z so-numbering)

 *    1.0.6i                        10007  10.6i

 *    1.0.6j                        10007  2.1.0.6j (incompatible with 1.0.0)

 *    1.0.7beta11-14        DLLNUM  10007  2.1.0.7beta11-14 (binary compatible)

 *    1.0.7beta15-18           1    10007  2.1.0.7beta15-18 (binary compatible)

 *    1.0.7rc1-2               1    10007  2.1.0.7rc1-2 (binary compatible)

 *    1.0.7                    1    10007  (still compatible)

 *    1.0.8beta1-4             1    10008  2.1.0.8beta1-4

 *    1.0.8rc1                 1    10008  2.1.0.8rc1

 *    1.0.8                    1    10008  2.1.0.8

 *    1.0.9beta1-6             1    10009  2.1.0.9beta1-6

 *    1.0.9rc1                 1    10009  2.1.0.9rc1

 *    1.0.9beta7-10            1    10009  2.1.0.9beta7-10

 *    1.0.9rc2                 1    10009  2.1.0.9rc2

 *    1.0.9                    1    10009  2.1.0.9

 *    1.0.10beta1              1    10010  2.1.0.10beta1

 *    1.0.10rc1                1    10010  2.1.0.10rc1

 *    1.0.10                   1    10010  2.1.0.10

 *    1.0.11beta1-3            1    10011  2.1.0.11beta1-3

 *    1.0.11rc1                1    10011  2.1.0.11rc1

 *    1.0.11                   1    10011  2.1.0.11

 *    1.0.12beta1-2            2    10012  2.1.0.12beta1-2

 *    1.0.12rc1                2    10012  2.1.0.12rc1

 *    1.0.12                   2    10012  2.1.0.12

 *    1.1.0a-f                 -    10100  2.1.1.0a-f (branch abandoned)

 *    1.2.0beta1-2             2    10200  2.1.2.0beta1-2

 *    1.2.0beta3-5             3    10200  3.1.2.0beta3-5

 *    1.2.0rc1                 3    10200  3.1.2.0rc1

 *    1.2.0                    3    10200  3.1.2.0

 *    1.2.1beta1-4             3    10201  3.1.2.1beta1-4

 *    1.2.1rc1-2               3    10201  3.1.2.1rc1-2

 *    1.2.1                    3    10201  3.1.2.1

 *    1.2.2beta1-6            12    10202  12.so.0.1.2.2beta1-6

 *    1.0.13beta1             10    10013  10.so.0.1.0.13beta1

 *    1.0.13rc1               10    10013  10.so.0.1.0.13rc1

 *    1.2.2rc1                12    10202  12.so.0.1.2.2rc1

 *    1.0.13                  10    10013  10.so.0.1.0.13

 *    1.2.2                   12    10202  12.so.0.1.2.2

 *    1.2.3rc1-6              12    10203  12.so.0.1.2.3rc1-6

 *    1.2.3                   12    10203  12.so.0.1.2.3

 *    1.2.4beta1-3            13    10204  12.so.0.1.2.4beta1-3

 *    1.0.14rc1               13    10014  10.so.0.1.0.14rc1

 *    1.2.4rc1                13    10204  12.so.0.1.2.4rc1

 *    1.0.14                  10    10014  10.so.0.1.0.14

 *    1.2.4                   13    10204  12.so.0.1.2.4

 *    1.2.5beta1-2            13    10205  12.so.0.1.2.5beta1-2

 *    1.0.15rc1-3             10    10015  10.so.0.1.0.15rc1-3

 *    1.2.5rc1-3              13    10205  12.so.0.1.2.5rc1-3

 *    1.0.15                  10    10015  10.so.0.1.0.15

 *    1.2.5                   13    10205  12.so.0.1.2.5

 *    1.2.6beta1-4            13    10206  12.so.0.1.2.6beta1-4

 *    1.0.16                  10    10016  10.so.0.1.0.16

 *    1.2.6                   13    10206  12.so.0.1.2.6

 *    1.2.7beta1-2            13    10207  12.so.0.1.2.7beta1-2

 *    1.0.17rc1               10    10017  12.so.0.1.0.17rc1

 *    1.2.7rc1                13    10207  12.so.0.1.2.7rc1

 *    1.0.17                  10    10017  12.so.0.1.0.17

 *    1.2.7                   13    10207  12.so.0.1.2.7

 *

 *    Henceforth the source version will match the shared-library major

 *    and minor numbers; the shared-library major version number will be

 *    used for changes in backward compatibility, as it is intended.  The

 *    PNG_LIBPNG_VER macro, which is not used within libpng but is available

 *    for applications, is an unsigned integer of the form xyyzz corresponding

 *    to the source version x.y.z (leading zeros in y and z).  Beta versions

 *    were given the previous public release number plus a letter, until

 *    version 1.0.6j; from then on they were given the upcoming public

 *    release number plus "betaNN" or "rcN".

 *

 *    Binary incompatibility exists only when applications make direct access

 *    to the info_ptr or png_ptr members through png.h, and the compiled

 *    application is loaded with a different version of the library.

 *

 *    DLLNUM will change each time there are forward or backward changes

 *    in binary compatibility (e.g., when a new feature is added).

 *

 * See libpng.txt or libpng.3 for more information.  The PNG specification

 * is available as a W3C Recommendation and as an ISO Specification,

 * <http://www.w3.org/TR/2003/REC-PNG-20031110/

 */



/*

 * COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:

 *

 * If you modify libpng you may insert additional notices immediately following

 * this sentence.

 *

 * libpng versions 1.2.6, August 15, 2004, through 1.2.7, September 12, 2004, are

 * Copyright (c) 2004 Glenn Randers-Pehrson, and are

 * distributed according to the same disclaimer and license as libpng-1.2.5

 * with the following individual added to the list of Contributing Authors:

 *

 *    Cosmin Truta

 *

 * libpng versions 1.0.7, July 1, 2000, through 1.2.5, October 3, 2002, are

 * Copyright (c) 2000-2002 Glenn Randers-Pehrson, and are

 * distributed according to the same disclaimer and license as libpng-1.0.6

 * with the following individuals added to the list of Contributing Authors:

 *

 *    Simon-Pierre Cadieux

 *    Eric S. Raymond

 *    Gilles Vollant

 *

 * and with the following additions to the disclaimer:

 *

 *    There is no warranty against interference with your enjoyment of the

 *    library or against infringement.  There is no warranty that our

 *    efforts or the library will fulfill any of your particular purposes

 *    or needs.  This library is provided with all faults, and the entire

 *    risk of satisfactory quality, performance, accuracy, and effort is with

 *    the user.

 *

 * libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are

 * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson, and are

 * distributed according to the same disclaimer and license as libpng-0.96,

 * with the following individuals added to the list of Contributing Authors:

 *

 *    Tom Lane

 *    Glenn Randers-Pehrson

 *    Willem van Schaik

 *

 * libpng versions 0.89, June 1996, through 0.96, May 1997, are

 * Copyright (c) 1996, 1997 Andreas Dilger

 * Distributed according to the same disclaimer and license as libpng-0.88,

 * with the following individuals added to the list of Contributing Authors:

 *

 *    John Bowler

 *    Kevin Bracey

 *    Sam Bushell

 *    Magnus Holmgren

 *    Greg Roelofs

 *    Tom Tanner

 *

 * libpng versions 0.5, May 1995, through 0.88, January 1996, are

 * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.

 *

 * For the purposes of this copyright and license, "Contributing Authors"

 * is defined as the following set of individuals:

 *

 *    Andreas Dilger

 *    Dave Martindale

 *    Guy Eric Schalnat

 *    Paul Schmidt

 *    Tim Wegner

 *

 * The PNG Reference Library is supplied "AS IS".  The Contributing Authors

 * and Group 42, Inc. disclaim all warranties, expressed or implied,

 * including, without limitation, the warranties of merchantability and of

 * fitness for any purpose.  The Contributing Authors and Group 42, Inc.

 * assume no liability for direct, indirect, incidental, special, exemplary,

 * or consequential damages, which may result from the use of the PNG

 * Reference Library, even if advised of the possibility of such damage.

 *

 * Permission is hereby granted to use, copy, modify, and distribute this

 * source code, or portions hereof, for any purpose, without fee, subject

 * to the following restrictions:

 *

 * 1. The origin of this source code must not be misrepresented.

 *

 * 2. Altered versions must be plainly marked as such and

 * must not be misrepresented as being the original source.

 *

 * 3. This Copyright notice may not be removed or altered from

 *    any source or altered source distribution.

 *

 * The Contributing Authors and Group 42, Inc. specifically permit, without

 * fee, and encourage the use of this source code as a component to

 * supporting the PNG file format in commercial products.  If you use this

 * source code in a product, acknowledgment is not required but would be

 * appreciated.

 */



/*

 * A "png_get_copyright" function is available, for convenient use in "about"

 * boxes and the like:

 *

 * printf("%s",png_get_copyright(NULL));

 *

 * Also, the PNG logo (in PNG format, of course) is supplied in the

 * files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).

 */



/*

 * Libpng is OSI Certified Open Source Software.  OSI Certified is a

 * certification mark of the Open Source Initiative.

 */



/*

 * The contributing authors would like to thank all those who helped

 * with testing, bug fixes, and patience.  This wouldn't have been

 * possible without all of you.

 *

 * Thanks to Frank J. T. Wojcik for helping with the documentation.

 */



/*

 * Y2K compliance in libpng:

 * =========================

 *

 *    September 12, 2004

 *

 *    Since the PNG Development group is an ad-hoc body, we can't make

 *    an official declaration.

 *

 *    This is your unofficial assurance that libpng from version 0.71 and

 *    upward through 1.2.7 are Y2K compliant.  It is my belief that earlier

 *    versions were also Y2K compliant.

 *

 *    Libpng only has three year fields.  One is a 2-byte unsigned integer

 *    that will hold years up to 65535.  The other two hold the date in text

 *    format, and will hold years up to 9999.

 *

 *    The integer is

 *        "png_uint_16 year" in png_time_struct.

 *

 *    The strings are

 *        "png_charp time_buffer" in png_struct and

 *        "near_time_buffer", which is a local character string in png.c.

 *

 *    There are seven time-related functions:

 *        png.c: png_convert_to_rfc_1123() in png.c

 *          (formerly png_convert_to_rfc_1152() in error)

 *        png_convert_from_struct_tm() in pngwrite.c, called in pngwrite.c

 *        png_convert_from_time_t() in pngwrite.c

 *        png_get_tIME() in pngget.c

 *        png_handle_tIME() in pngrutil.c, called in pngread.c

 *        png_set_tIME() in pngset.c

 *        png_write_tIME() in pngwutil.c, called in pngwrite.c

 *

 *    All handle dates properly in a Y2K environment.  The

 *    png_convert_from_time_t() function calls gmtime() to convert from system

 *    clock time, which returns (year - 1900), which we properly convert to

 *    the full 4-digit year.  There is a possibility that applications using

 *    libpng are not passing 4-digit years into the png_convert_to_rfc_1123()

 *    function, or that they are incorrectly passing only a 2-digit year

 *    instead of "year - 1900" into the png_convert_from_struct_tm() function,

 *    but this is not under our control.  The libpng documentation has always

 *    stated that it works with 4-digit years, and the APIs have been

 *    documented as such.

 *

 *    The tIME chunk itself is also Y2K compliant.  It uses a 2-byte unsigned

 *    integer to hold the year, and can hold years as large as 65535.

 *

 *    zlib, upon which libpng depends, is also Y2K compliant.  It contains

 *    no date-related code.

 *

 *       Glenn Randers-Pehrson

 *       libpng maintainer

 *       PNG Development Group

 */



#ifndef PNG_H

#define PNG_H



/* This is not the place to learn how to use libpng.  The file libpng.txt

 * describes how to use libpng, and the file example.c summarizes it

 * with some code on which to build.  This file is useful for looking

 * at the actual function definitions and structure components.

 */



/* Version information for png.h - this should match the version in png.c */

#define PNG_LIBPNG_VER_STRING "1.2.7"

#define PNG_HEADER_VERSION_STRING \

   " libpng version 1.2.7 - September 12, 2004 (header)\n"



#define PNG_LIBPNG_VER_SONUM   0

#define PNG_LIBPNG_VER_DLLNUM  %DLLNUM%



/* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */

#define PNG_LIBPNG_VER_MAJOR   1

#define PNG_LIBPNG_VER_MINOR   2

#define PNG_LIBPNG_VER_RELEASE 7

/* This should match the numeric part of the final component of

 * PNG_LIBPNG_VER_STRING, omitting any leading zero: */



#define PNG_LIBPNG_VER_BUILD  0



#define PNG_LIBPNG_BUILD_ALPHA    1

#define PNG_LIBPNG_BUILD_BETA     2

#define PNG_LIBPNG_BUILD_RC       3

#define PNG_LIBPNG_BUILD_STABLE   4

#define PNG_LIBPNG_BUILD_TYPEMASK 7

#define PNG_LIBPNG_BUILD_PATCH    8 /* Can be OR'ed with STABLE only */

#define PNG_LIBPNG_BUILD_TYPE 4



/* Careful here.  At one time, Guy wanted to use 082, but that would be octal.

 * We must not include leading zeros.

 * Versions 0.7 through 1.0.0 were in the range 0 to 100 here (only

 * version 1.0.0 was mis-numbered 100 instead of 10000).  From

 * version 1.0.1 it's    xxyyzz, where x=major, y=minor, z=release */

#define PNG_LIBPNG_VER 10207 /* 1.2.7 */



#ifndef PNG_VERSION_INFO_ONLY



/* include the compression library's header */

#include "zlib.h"



/* include all user configurable info, including optional assembler routines */

#include "pngconf.h"



/* Inhibit C++ name-mangling for libpng functions but not for system calls. */

#ifdef __cplusplus

extern "C" {

#endif /* __cplusplus */



/* This file is arranged in several sections.  The first section contains

 * structure and type definitions.  The second section contains the external

 * library functions, while the third has the internal library functions,

 * which applications aren't expected to use directly.

 */



#ifndef PNG_NO_TYPECAST_NULL

#define int_p_NULL                (int *)NULL

#define png_bytep_NULL            (png_bytep)NULL

#define png_bytepp_NULL           (png_bytepp)NULL

#define png_doublep_NULL          (png_doublep)NULL

#define png_error_ptr_NULL        (png_error_ptr)NULL

#define png_flush_ptr_NULL        (png_flush_ptr)NULL

#define png_free_ptr_NULL         (png_free_ptr)NULL

#define png_infopp_NULL           (png_infopp)NULL

#define png_malloc_ptr_NULL       (png_malloc_ptr)NULL

#define png_read_status_ptr_NULL  (png_read_status_ptr)NULL

#define png_rw_ptr_NULL           (png_rw_ptr)NULL

#define png_structp_NULL          (png_structp)NULL

#define png_uint_16p_NULL         (png_uint_16p)NULL

#define png_voidp_NULL            (png_voidp)NULL

#define png_write_status_ptr_NULL (png_write_status_ptr)NULL

#else

#define int_p_NULL                NULL

#define png_bytep_NULL            NULL

#define png_bytepp_NULL           NULL

#define png_doublep_NULL          NULL

#define png_error_ptr_NULL        NULL

#define png_flush_ptr_NULL        NULL

#define png_free_ptr_NULL         NULL

#define png_infopp_NULL           NULL

#define png_malloc_ptr_NULL       NULL

#define png_read_status_ptr_NULL  NULL

#define png_rw_ptr_NULL           NULL

#define png_structp_NULL          NULL

#define png_uint_16p_NULL         NULL

#define png_voidp_NULL            NULL

#define png_write_status_ptr_NULL NULL

#endif



/* variables declared in png.c - only it needs to define PNG_NO_EXTERN */

#if !defined(PNG_NO_EXTERN) || defined(PNG_ALWAYS_EXTERN)

/* Version information for C files, stored in png.c.  This had better match

 * the version above.

 */

#ifdef PNG_USE_GLOBAL_ARRAYS

PNG_EXPORT_VAR (const char) png_libpng_ver[18];

  /* need room for 99.99.99beta99z */

#else

#define png_libpng_ver png_get_header_ver(NULL)

#endif



#ifdef PNG_USE_GLOBAL_ARRAYS

/* This was removed in version 1.0.5c */

/* Structures to facilitate easy interlacing.  See png.c for more details */

PNG_EXPORT_VAR (const int FARDATA) png_pass_start[7];

PNG_EXPORT_VAR (const int FARDATA) png_pass_inc[7];

PNG_EXPORT_VAR (const int FARDATA) png_pass_ystart[7];

PNG_EXPORT_VAR (const int FARDATA) png_pass_yinc[7];

PNG_EXPORT_VAR (const int FARDATA) png_pass_mask[7];

PNG_EXPORT_VAR (const int FARDATA) png_pass_dsp_mask[7];

#ifdef PNG_HAVE_ASSEMBLER_COMBINE_ROW

PNG_EXPORT_VAR (const int FARDATA) png_pass_width[7];

#endif

/* This isn't currently used.  If you need it, see png.c for more details.

PNG_EXPORT_VAR (const int FARDATA) png_pass_height[7];

*/

#endif



#endif /* PNG_NO_EXTERN */



/* Three color definitions.  The order of the red, green, and blue, (and the

 * exact size) is not important, although the size of the fields need to

 * be png_byte or png_uint_16 (as defined below).

 */

typedef struct png_color_struct

{

   png_byte red;

   png_byte green;

   png_byte blue;

} png_color;

typedef png_color FAR * png_colorp;

typedef png_color FAR * FAR * png_colorpp;



typedef struct png_color_16_struct

{

   png_byte index;    /* used for palette files */

   png_uint_16 red;   /* for use in red green blue files */

   png_uint_16 green;

   png_uint_16 blue;

   png_uint_16 gray;  /* for use in grayscale files */

} png_color_16;

typedef png_color_16 FAR * png_color_16p;

typedef png_color_16 FAR * FAR * png_color_16pp;



typedef struct png_color_8_struct

{

   png_byte red;   /* for use in red green blue files */

   png_byte green;

   png_byte blue;

   png_byte gray;  /* for use in grayscale files */

   png_byte alpha; /* for alpha channel files */

} png_color_8;

typedef png_color_8 FAR * png_color_8p;

typedef png_color_8 FAR * FAR * png_color_8pp;



/*

 * The following two structures are used for the in-core representation

 * of sPLT chunks.

 */

typedef struct png_sPLT_entry_struct

{

   png_uint_16 red;

   png_uint_16 green;

   png_uint_16 blue;

   png_uint_16 alpha;

   png_uint_16 frequency;

} png_sPLT_entry;

typedef png_sPLT_entry FAR * png_sPLT_entryp;

typedef png_sPLT_entry FAR * FAR * png_sPLT_entrypp;



/*  When the depth of the sPLT palette is 8 bits, the color and alpha samples

 *  occupy the LSB of their respective members, and the MSB of each member

 *  is zero-filled.  The frequency member always occupies the full 16 bits.

 */



typedef struct png_sPLT_struct

{

   png_charp name;           /* palette name */

   png_byte depth;           /* depth of palette samples */

   png_sPLT_entryp entries;  /* palette entries */

   png_int_32 nentries;      /* number of palette entries */

} png_sPLT_t;

typedef png_sPLT_t FAR * png_sPLT_tp;

typedef png_sPLT_t FAR * FAR * png_sPLT_tpp;



#ifdef PNG_TEXT_SUPPORTED

/* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file,

 * and whether that contents is compressed or not.  The "key" field

 * points to a regular zero-terminated C string.  The "text", "lang", and

 * "lang_key" fields can be regular C strings, empty strings, or NULL pointers.

 * However, the * structure returned by png_get_text() will always contain

 * regular zero-terminated C strings (possibly empty), never NULL pointers,

 * so they can be safely used in printf() and other string-handling functions.

 */

typedef struct png_text_struct

{

   int  compression;       /* compression value:

                             -1: tEXt, none

                              0: zTXt, deflate

                              1: iTXt, none

                              2: iTXt, deflate  */

   png_charp key;          /* keyword, 1-79 character description of "text" */

   png_charp text;         /* comment, may be an empty string (ie "")

                              or a NULL pointer */

   png_size_t text_length; /* length of the text string */

#ifdef PNG_iTXt_SUPPORTED

   png_size_t itxt_length; /* length of the itxt string */

   png_charp lang;         /* language code, 0-79 characters

                              or a NULL pointer */

   png_charp lang_key;     /* keyword translated UTF-8 string, 0 or more

                              chars or a NULL pointer */

#endif

} png_text;

typedef png_text FAR * png_textp;

typedef png_text FAR * FAR * png_textpp;

#endif



/* Supported compression types for text in PNG files (tEXt, and zTXt).

 * The values of the PNG_TEXT_COMPRESSION_ defines should NOT be changed. */

#define PNG_TEXT_COMPRESSION_NONE_WR -3

#define PNG_TEXT_COMPRESSION_zTXt_WR -2

#define PNG_TEXT_COMPRESSION_NONE    -1

#define PNG_TEXT_COMPRESSION_zTXt     0

#define PNG_ITXT_COMPRESSION_NONE     1

#define PNG_ITXT_COMPRESSION_zTXt     2

#define PNG_TEXT_COMPRESSION_LAST     3  /* Not a valid value */



/* png_time is a way to hold the time in an machine independent way.

 * Two conversions are provided, both from time_t and struct tm.  There

 * is no portable way to convert to either of these structures, as far

 * as I know.  If you know of a portable way, send it to me.  As a side

 * note - PNG has always been Year 2000 compliant!

 */

typedef struct png_time_struct

{

   png_uint_16 year; /* full year, as in, 1995 */

   png_byte month;   /* month of year, 1 - 12 */

   png_byte day;     /* day of month, 1 - 31 */

   png_byte hour;    /* hour of day, 0 - 23 */

   png_byte minute;  /* minute of hour, 0 - 59 */

   png_byte second;  /* second of minute, 0 - 60 (for leap seconds) */

} png_time;

typedef png_time FAR * png_timep;

typedef png_time FAR * FAR * png_timepp;



#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)

/* png_unknown_chunk is a structure to hold queued chunks for which there is

 * no specific support.  The idea is that we can use this to queue

 * up private chunks for output even though the library doesn't actually

 * know about their semantics.

 */

typedef struct png_unknown_chunk_t

{

    png_byte name[5];

    png_byte *data;

    png_size_t size;



    /* libpng-using applications should NOT directly modify this byte. */

    png_byte location; /* mode of operation at read time */

}

png_unknown_chunk;

typedef png_unknown_chunk FAR * png_unknown_chunkp;

typedef png_unknown_chunk FAR * FAR * png_unknown_chunkpp;

#endif



/* png_info is a structure that holds the information in a PNG file so

 * that the application can find out the characteristics of the image.

 * If you are reading the file, this structure will tell you what is

 * in the PNG file.  If you are writing the file, fill in the information

 * you want to put into the PNG file, then call png_write_info().

 * The names chosen should be very close to the PNG specification, so

 * consult that document for information about the meaning of each field.

 *

 * With libpng < 0.95, it was only possible to directly set and read the

 * the values in the png_info_struct, which meant that the contents and

 * order of the values had to remain fixed.  With libpng 0.95 and later,

 * however, there are now functions that abstract the contents of

 * png_info_struct from the application, so this makes it easier to use

 * libpng with dynamic libraries, and even makes it possible to use

 * libraries that don't have all of the libpng ancillary chunk-handing

 * functionality.

 *

 * In any case, the order of the parameters in png_info_struct should NOT

 * be changed for as long as possible to keep compatibility with applications

 * that use the old direct-access method with png_info_struct.

 *

 * The following members may have allocated storage attached that should be

 * cleaned up before the structure is discarded: palette, trans, text,

 * pcal_purpose, pcal_units, pcal_params, hist, iccp_name, iccp_profile,

 * splt_palettes, scal_unit, row_pointers, and unknowns.   By default, these

 * are automatically freed when the info structure is deallocated, if they were

 * allocated internally by libpng.  This behavior can be changed by means

 * of the png_data_freer() function.

 *

 * More allocation details: all the chunk-reading functions that

 * change these members go through the corresponding png_set_*

 * functions.  A function to clear these members is available: see

 * png_free_data().  The png_set_* functions do not depend on being

 * able to point info structure members to any of the storage they are

 * passed (they make their own copies), EXCEPT that the png_set_text

 * functions use the same storage passed to them in the text_ptr or

 * itxt_ptr structure argument, and the png_set_rows and png_set_unknowns

 * functions do not make their own copies.

 */

typedef struct png_info_struct

{

   /* the following are necessary for every PNG file */

   png_uint_32 width;       /* width of image in pixels (from IHDR) */

   png_uint_32 height;      /* height of image in pixels (from IHDR) */

   png_uint_32 valid;       /* valid chunk data (see PNG_INFO_ below) */

   png_uint_32 rowbytes;    /* bytes needed to hold an untransformed row */

   png_colorp palette;      /* array of color values (valid & PNG_INFO_PLTE) */

   png_uint_16 num_palette; /* number of color entries in "palette" (PLTE) */

   png_uint_16 num_trans;   /* number of transparent palette color (tRNS) */

   png_byte bit_depth;      /* 1, 2, 4, 8, or 16 bits/channel (from IHDR) */

   png_byte color_type;     /* see PNG_COLOR_TYPE_ below (from IHDR) */

   /* The following three should have been named *_method not *_type */

   png_byte compression_type; /* must be PNG_COMPRESSION_TYPE_BASE (IHDR) */

   png_byte filter_type;    /* must be PNG_FILTER_TYPE_BASE (from IHDR) */

   png_byte interlace_type; /* One of PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */



   /* The following is informational only on read, and not used on writes. */

   png_byte channels;       /* number of data channels per pixel (1, 2, 3, 4) */

   png_byte pixel_depth;    /* number of bits per pixel */

   png_byte spare_byte;     /* to align the data, and for future use */

   png_byte signature[8];   /* magic bytes read by libpng from start of file */



   /* The rest of the data is optional.  If you are reading, check the

    * valid field to see if the information in these are valid.  If you

    * are writing, set the valid field to those chunks you want written,

    * and initialize the appropriate fields below.

    */



#if defined(PNG_gAMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED)

   /* The gAMA chunk describes the gamma characteristics of the system

    * on which the image was created, normally in the range [1.0, 2.5].

    * Data is valid if (valid & PNG_INFO_gAMA) is non-zero.

    */

   float gamma; /* gamma value of image, if (valid & PNG_INFO_gAMA) */

#endif



#if defined(PNG_sRGB_SUPPORTED)

    /* GR-P, 0.96a */

    /* Data valid if (valid & PNG_INFO_sRGB) non-zero. */

   png_byte srgb_intent; /* sRGB rendering intent [0, 1, 2, or 3] */

#endif



#if defined(PNG_TEXT_SUPPORTED)

   /* The tEXt, and zTXt chunks contain human-readable textual data in

    * uncompressed, compressed, and optionally compressed forms, respectively.

    * The data in "text" is an array of pointers to uncompressed,

    * null-terminated C strings. Each chunk has a keyword that describes the

    * textual data contained in that chunk.  Keywords are not required to be

    * unique, and the text string may be empty.  Any number of text chunks may

    * be in an image.

    */

   int num_text; /* number of comments read/to write */

   int max_text; /* current size of text array */

   png_textp text; /* array of comments read/to write */

#endif /* PNG_TEXT_SUPPORTED */



#if defined(PNG_tIME_SUPPORTED)

   /* The tIME chunk holds the last time the displayed image data was

    * modified.  See the png_time struct for the contents of this struct.

    */

   png_time mod_time;

#endif



#if defined(PNG_sBIT_SUPPORTED)

   /* The sBIT chunk specifies the number of significant high-order bits

    * in the pixel data.  Values are in the range [1, bit_depth], and are

    * only specified for the channels in the pixel data.  The contents of

    * the low-order bits is not specified.  Data is valid if

    * (valid & PNG_INFO_sBIT) is non-zero.

    */

   png_color_8 sig_bit; /* significant bits in color channels */

#endif



#if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_EXPAND_SUPPORTED) || \

defined(PNG_READ_BACKGROUND_SUPPORTED)

   /* The tRNS chunk supplies transparency data for paletted images and

    * other image types that don't need a full alpha channel.  There are

    * "num_trans" transparency values for a paletted image, stored in the

    * same order as the palette colors, starting from index 0.  Values

    * for the data are in the range [0, 255], ranging from fully transparent

    * to fully opaque, respectively.  For non-paletted images, there is a

    * single color specified that should be treated as fully transparent.

    * Data is valid if (valid & PNG_INFO_tRNS) is non-zero.

    */

   png_bytep trans; /* transparent values for paletted image */

   png_color_16 trans_values; /* transparent color for non-palette image */

#endif



#if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)

   /* The bKGD chunk gives the suggested image background color if the

    * display program does not have its own background color and the image

    * is needs to composited onto a background before display.  The colors

    * in "background" are normally in the same color space/depth as the

    * pixel data.  Data is valid if (valid & PNG_INFO_bKGD) is non-zero.

    */

   png_color_16 background;

#endif



#if defined(PNG_oFFs_SUPPORTED)

   /* The oFFs chunk gives the offset in "offset_unit_type" units rightwards

    * and downwards from the top-left corner of the display, page, or other

    * application-specific co-ordinate space.  See the PNG_OFFSET_ defines

    * below for the unit types.  Valid if (valid & PNG_INFO_oFFs) non-zero.

    */

   png_int_32 x_offset; /* x offset on page */

   png_int_32 y_offset; /* y offset on page */

   png_byte offset_unit_type; /* offset units type */

#endif



#if defined(PNG_pHYs_SUPPORTED)

   /* The pHYs chunk gives the physical pixel density of the image for

    * display or printing in "phys_unit_type" units (see PNG_RESOLUTION_

    * defines below).  Data is valid if (valid & PNG_INFO_pHYs) is non-zero.

    */

   png_uint_32 x_pixels_per_unit; /* horizontal pixel density */

   png_uint_32 y_pixels_per_unit; /* vertical pixel density */

   png_byte phys_unit_type; /* resolution type (see PNG_RESOLUTION_ below) */

#endif



#if defined(PNG_hIST_SUPPORTED)

   /* The hIST chunk contains the relative frequency or importance of the

    * various palette entries, so that a viewer can intelligently select a

    * reduced-color palette, if required.  Data is an array of "num_palette"

    * values in the range [0,65535]. Data valid if (valid & PNG_INFO_hIST)

    * is non-zero.

    */

   png_uint_16p hist;

#endif



#ifdef PNG_cHRM_SUPPORTED

   /* The cHRM chunk describes the CIE color characteristics of the monitor

    * on which the PNG was created.  This data allows the viewer to do gamut

    * mapping of the input image to ensure that the viewer sees the same

    * colors in the image as the creator.  Values are in the range

    * [0.0, 0.8].  Data valid if (valid & PNG_INFO_cHRM) non-zero.

    */

#ifdef PNG_FLOATING_POINT_SUPPORTED

   float x_white;

   float y_white;

   float x_red;

   float y_red;

   float x_green;

   float y_green;

   float x_blue;

   float y_blue;

#endif

#endif



#if defined(PNG_pCAL_SUPPORTED)

   /* The pCAL chunk describes a transformation between the stored pixel

    * values and original physical data values used to create the image.

    * The integer range [0, 2^bit_depth - 1] maps to the floating-point

    * range given by [pcal_X0, pcal_X1], and are further transformed by a

    * (possibly non-linear) transformation function given by "pcal_type"

    * and "pcal_params" into "pcal_units".  Please see the PNG_EQUATION_

    * defines below, and the PNG-Group's PNG extensions document for a

    * complete description of the transformations and how they should be

    * implemented, and for a description of the ASCII parameter strings.

    * Data values are valid if (valid & PNG_INFO_pCAL) non-zero.

    */

   png_charp pcal_purpose;  /* pCAL chunk description string */

   png_int_32 pcal_X0;      /* minimum value */

   png_int_32 pcal_X1;      /* maximum value */

   png_charp pcal_units;    /* Latin-1 string giving physical units */

   png_charpp pcal_params;  /* ASCII strings containing parameter values */

   png_byte pcal_type;      /* equation type (see PNG_EQUATION_ below) */

   png_byte pcal_nparams;   /* number of parameters given in pcal_params */

#endif



/* New members added in libpng-1.0.6 */

#ifdef PNG_FREE_ME_SUPPORTED

   png_uint_32 free_me;     /* flags items libpng is responsible for freeing */

#endif



#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)

   /* storage for unknown chunks that the library doesn't recognize. */

   png_unknown_chunkp unknown_chunks;

   png_size_t unknown_chunks_num;

#endif



#if defined(PNG_iCCP_SUPPORTED)

   /* iCCP chunk data. */

   png_charp iccp_name;     /* profile name */

   png_charp iccp_profile;  /* International Color Consortium profile data */

                            /* Note to maintainer: should be png_bytep */

   png_uint_32 iccp_proflen;  /* ICC profile data length */

   png_byte iccp_compression; /* Always zero */

#endif



#if defined(PNG_sPLT_SUPPORTED)

   /* data on sPLT chunks (there may be more than one). */

   png_sPLT_tp splt_palettes;

   png_uint_32 splt_palettes_num;

#endif



#if defined(PNG_sCAL_SUPPORTED)

   /* The sCAL chunk describes the actual physical dimensions of the

    * subject matter of the graphic.  The chunk contains a unit specification

    * a byte value, and two ASCII strings representing floating-point

    * values.  The values are width and height corresponsing to one pixel

    * in the image.  This external representation is converted to double

    * here.  Data values are valid if (valid & PNG_INFO_sCAL) is non-zero.

    */

   png_byte scal_unit;         /* unit of physical scale */

#ifdef PNG_FLOATING_POINT_SUPPORTED

   double scal_pixel_width;    /* width of one pixel */

   double scal_pixel_height;   /* height of one pixel */

#endif

#ifdef PNG_FIXED_POINT_SUPPORTED

   png_charp scal_s_width;     /* string containing height */

   png_charp scal_s_height;    /* string containing width */

#endif

#endif



#if defined(PNG_INFO_IMAGE_SUPPORTED)

   /* Memory has been allocated if (valid & PNG_ALLOCATED_INFO_ROWS) non-zero */

   /* Data valid if (valid & PNG_INFO_IDAT) non-zero */

   png_bytepp row_pointers;        /* the image bits */

#endif



#if defined(PNG_FIXED_POINT_SUPPORTED) && defined(PNG_gAMA_SUPPORTED)

   png_fixed_point int_gamma; /* gamma of image, if (valid & PNG_INFO_gAMA) */

#endif



#if defined(PNG_cHRM_SUPPORTED) && defined(PNG_FIXED_POINT_SUPPORTED)

   png_fixed_point int_x_white;

   png_fixed_point int_y_white;

   png_fixed_point int_x_red;

   png_fixed_point int_y_red;

   png_fixed_point int_x_green;

   png_fixed_point int_y_green;

   png_fixed_point int_x_blue;

   png_fixed_point int_y_blue;

#endif



} png_info;



typedef png_info FAR * png_infop;

typedef png_info FAR * FAR * png_infopp;



/* Maximum positive integer used in PNG is (2^31)-1 */

#define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL)

#define PNG_UINT_32_MAX (~((png_uint_32)0))

#define PNG_SIZE_MAX (~((png_size_t)0))

/* PNG_MAX_UINT is deprecated; use PNG_UINT_31_MAX instead. */

#define PNG_MAX_UINT PNG_UINT_31_MAX



/* These describe the color_type field in png_info. */

/* color type masks */

#define PNG_COLOR_MASK_PALETTE    1

#define PNG_COLOR_MASK_COLOR      2

#define PNG_COLOR_MASK_ALPHA      4



/* color types.  Note that not all combinations are legal */

#define PNG_COLOR_TYPE_GRAY 0

#define PNG_COLOR_TYPE_PALETTE  (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)

#define PNG_COLOR_TYPE_RGB        (PNG_COLOR_MASK_COLOR)

#define PNG_COLOR_TYPE_RGB_ALPHA  (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)

#define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)

/* aliases */

#define PNG_COLOR_TYPE_RGBA  PNG_COLOR_TYPE_RGB_ALPHA

#define PNG_COLOR_TYPE_GA  PNG_COLOR_TYPE_GRAY_ALPHA



/* This is for compression type. PNG 1.0-1.2 only define the single type. */

#define PNG_COMPRESSION_TYPE_BASE 0 /* Deflate method 8, 32K window */

#define PNG_COMPRESSION_TYPE_DEFAULT PNG_COMPRESSION_TYPE_BASE



/* This is for filter type. PNG 1.0-1.2 only define the single type. */

#define PNG_FILTER_TYPE_BASE      0 /* Single row per-byte filtering */

#define PNG_INTRAPIXEL_DIFFERENCING 64 /* Used only in MNG datastreams */

#define PNG_FILTER_TYPE_DEFAULT   PNG_FILTER_TYPE_BASE



/* These are for the interlacing type.  These values should NOT be changed. */

#define PNG_INTERLACE_NONE        0 /* Non-interlaced image */

#define PNG_INTERLACE_ADAM7       1 /* Adam7 interlacing */

#define PNG_INTERLACE_LAST        2 /* Not a valid value */



/* These are for the oFFs chunk.  These values should NOT be changed. */

#define PNG_OFFSET_PIXEL          0 /* Offset in pixels */

#define PNG_OFFSET_MICROMETER     1 /* Offset in micrometers (1/10^6 meter) */

#define PNG_OFFSET_LAST           2 /* Not a valid value */



/* These are for the pCAL chunk.  These values should NOT be changed. */

#define PNG_EQUATION_LINEAR       0 /* Linear transformation */

#define PNG_EQUATION_BASE_E       1 /* Exponential base e transform */

#define PNG_EQUATION_ARBITRARY    2 /* Arbitrary base exponential transform */

#define PNG_EQUATION_HYPERBOLIC   3 /* Hyperbolic sine transformation */

#define PNG_EQUATION_LAST         4 /* Not a valid value */



/* These are for the sCAL chunk.  These values should NOT be changed. */

#define PNG_SCALE_UNKNOWN         0 /* unknown unit (image scale) */

#define PNG_SCALE_METER           1 /* meters per pixel */

#define PNG_SCALE_RADIAN          2 /* radians per pixel */

#define PNG_SCALE_LAST            3 /* Not a valid value */



/* These are for the pHYs chunk.  These values should NOT be changed. */

#define PNG_RESOLUTION_UNKNOWN    0 /* pixels/unknown unit (aspect ratio) */

#define PNG_RESOLUTION_METER      1 /* pixels/meter */

#define PNG_RESOLUTION_LAST       2 /* Not a valid value */



/* These are for the sRGB chunk.  These values should NOT be changed. */

#define PNG_sRGB_INTENT_PERCEPTUAL 0

#define PNG_sRGB_INTENT_RELATIVE   1

#define PNG_sRGB_INTENT_SATURATION 2

#define PNG_sRGB_INTENT_ABSOLUTE   3

#define PNG_sRGB_INTENT_LAST       4 /* Not a valid value */



/* This is for text chunks */

#define PNG_KEYWORD_MAX_LENGTH     79



/* Maximum number of entries in PLTE/sPLT/tRNS arrays */

#define PNG_MAX_PALETTE_LENGTH    256



/* These determine if an ancillary chunk's data has been successfully read

 * from the PNG header, or if the application has filled in the corresponding

 * data in the info_struct to be written into the output file.  The values

 * of the PNG_INFO_<chunk> defines should NOT be changed.

 */

#define PNG_INFO_gAMA 0x0001

#define PNG_INFO_sBIT 0x0002

#define PNG_INFO_cHRM 0x0004

#define PNG_INFO_PLTE 0x0008

#define PNG_INFO_tRNS 0x0010

#define PNG_INFO_bKGD 0x0020

#define PNG_INFO_hIST 0x0040

#define PNG_INFO_pHYs 0x0080

#define PNG_INFO_oFFs 0x0100

#define PNG_INFO_tIME 0x0200

#define PNG_INFO_pCAL 0x0400

#define PNG_INFO_sRGB 0x0800   /* GR-P, 0.96a */

#define PNG_INFO_iCCP 0x1000   /* ESR, 1.0.6 */

#define PNG_INFO_sPLT 0x2000   /* ESR, 1.0.6 */

#define PNG_INFO_sCAL 0x4000   /* ESR, 1.0.6 */

#define PNG_INFO_IDAT 0x8000L  /* ESR, 1.0.6 */



/* This is used for the transformation routines, as some of them

 * change these values for the row.  It also should enable using

 * the routines for other purposes.

 */

typedef struct png_row_info_struct

{

   png_uint_32 width; /* width of row */

   png_uint_32 rowbytes; /* number of bytes in row */

   png_byte color_type; /* color type of row */

   png_byte bit_depth; /* bit depth of row */

   png_byte channels; /* number of channels (1, 2, 3, or 4) */

   png_byte pixel_depth; /* bits per pixel (depth * channels) */

} png_row_info;



typedef png_row_info FAR * png_row_infop;

typedef png_row_info FAR * FAR * png_row_infopp;



/* These are the function types for the I/O functions and for the functions

 * that allow the user to override the default I/O functions with his or her

 * own.  The png_error_ptr type should match that of user-supplied warning

 * and error functions, while the png_rw_ptr type should match that of the

 * user read/write data functions.

 */

typedef struct png_struct_def png_struct;

typedef png_struct FAR * png_structp;



typedef void (PNGAPI *png_error_ptr) PNGARG((png_structp, png_const_charp));

typedef void (PNGAPI *png_rw_ptr) PNGARG((png_structp, png_bytep, png_size_t));

typedef void (PNGAPI *png_flush_ptr) PNGARG((png_structp));

typedef void (PNGAPI *png_read_status_ptr) PNGARG((png_structp, png_uint_32,

   int));

typedef void (PNGAPI *png_write_status_ptr) PNGARG((png_structp, png_uint_32,

   int));



#ifdef PNG_PROGRESSIVE_READ_SUPPORTED

typedef void (PNGAPI *png_progressive_info_ptr) PNGARG((png_structp, png_infop));

typedef void (PNGAPI *png_progressive_end_ptr) PNGARG((png_structp, png_infop));

typedef void (PNGAPI *png_progressive_row_ptr) PNGARG((png_structp, png_bytep,

   png_uint_32, int));

#endif



#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \

    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) || \

    defined(PNG_LEGACY_SUPPORTED)

typedef void (PNGAPI *png_user_transform_ptr) PNGARG((png_structp,

    png_row_infop, png_bytep));

#endif



#if defined(PNG_USER_CHUNKS_SUPPORTED)

typedef int (PNGAPI *png_user_chunk_ptr) PNGARG((png_structp, png_unknown_chunkp));

#endif

#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)

typedef void (PNGAPI *png_unknown_chunk_ptr) PNGARG((png_structp));

#endif



/* Transform masks for the high-level interface */

#define PNG_TRANSFORM_IDENTITY       0x0000    /* read and write */

#define PNG_TRANSFORM_STRIP_16       0x0001    /* read only */

#define PNG_TRANSFORM_STRIP_ALPHA    0x0002    /* read only */

#define PNG_TRANSFORM_PACKING        0x0004    /* read and write */

#define PNG_TRANSFORM_PACKSWAP       0x0008    /* read and write */

#define PNG_TRANSFORM_EXPAND         0x0010    /* read only */

#define PNG_TRANSFORM_INVERT_MONO    0x0020    /* read and write */

#define PNG_TRANSFORM_SHIFT          0x0040    /* read and write */

#define PNG_TRANSFORM_BGR            0x0080    /* read and write */

#define PNG_TRANSFORM_SWAP_ALPHA     0x0100    /* read and write */

#define PNG_TRANSFORM_SWAP_ENDIAN    0x0200    /* read and write */

#define PNG_TRANSFORM_INVERT_ALPHA   0x0400    /* read and write */

#define PNG_TRANSFORM_STRIP_FILLER   0x0800    /* WRITE only */



/* Flags for MNG supported features */

#define PNG_FLAG_MNG_EMPTY_PLTE     0x01

#define PNG_FLAG_MNG_FILTER_64      0x04

#define PNG_ALL_MNG_FEATURES        0x05



typedef png_voidp (*png_malloc_ptr) PNGARG((png_structp, png_size_t));

typedef void (*png_free_ptr) PNGARG((png_structp, png_voidp));



/* The structure that holds the information to read and write PNG files.

 * The only people who need to care about what is inside of this are the

 * people who will be modifying the library for their own special needs.

 * It should NOT be accessed directly by an application, except to store

 * the jmp_buf.

 */



struct png_struct_def

{

#ifdef PNG_SETJMP_SUPPORTED

   jmp_buf jmpbuf;            /* used in png_error */

#endif

   png_error_ptr error_fn;    /* function for printing errors and aborting */

   png_error_ptr warning_fn;  /* function for printing warnings */

   png_voidp error_ptr;       /* user supplied struct for error functions */

   png_rw_ptr write_data_fn;  /* function for writing output data */

   png_rw_ptr read_data_fn;   /* function for reading input data */

   png_voidp io_ptr;          /* ptr to application struct for I/O functions */



#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED)

   png_user_transform_ptr read_user_transform_fn; /* user read transform */

#endif



#if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)

   png_user_transform_ptr write_user_transform_fn; /* user write transform */

#endif



/* These were added in libpng-1.0.2 */

#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)

#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \

    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)

   png_voidp user_transform_ptr; /* user supplied struct for user transform */

   png_byte user_transform_depth;    /* bit depth of user transformed pixels */

   png_byte user_transform_channels; /* channels in user transformed pixels */

#endif

#endif



   png_uint_32 mode;          /* tells us where we are in the PNG file */

   png_uint_32 flags;         /* flags indicating various things to libpng */

   png_uint_32 transformations; /* which transformations to perform */



   z_stream zstream;          /* pointer to decompression structure (below) */

   png_bytep zbuf;            /* buffer for zlib */

   png_size_t zbuf_size;      /* size of zbuf */

   int zlib_level;            /* holds zlib compression level */

   int zlib_method;           /* holds zlib compression method */

   int zlib_window_bits;      /* holds zlib compression window bits */

   int zlib_mem_level;        /* holds zlib compression memory level */

   int zlib_strategy;         /* holds zlib compression strategy */



   png_uint_32 width;         /* width of image in pixels */

   png_uint_32 height;        /* height of image in pixels */

   png_uint_32 num_rows;      /* number of rows in current pass */

   png_uint_32 usr_width;     /* width of row at start of write */

   png_uint_32 rowbytes;      /* size of row in bytes */

   png_uint_32 irowbytes;     /* size of current interlaced row in bytes */

   png_uint_32 iwidth;        /* width of current interlaced row in pixels */

   png_uint_32 row_number;    /* current row in interlace pass */

   png_bytep prev_row;        /* buffer to save previous (unfiltered) row */

   png_bytep row_buf;         /* buffer to save current (unfiltered) row */

   png_bytep sub_row;         /* buffer to save "sub" row when filtering */

   png_bytep up_row;          /* buffer to save "up" row when filtering */

   png_bytep avg_row;         /* buffer to save "avg" row when filtering */

   png_bytep paeth_row;       /* buffer to save "Paeth" row when filtering */

   png_row_info row_info;     /* used for transformation routines */



   png_uint_32 idat_size;     /* current IDAT size for read */

   png_uint_32 crc;           /* current chunk CRC value */

   png_colorp palette;        /* palette from the input file */

   png_uint_16 num_palette;   /* number of color entries in palette */

   png_uint_16 num_trans;     /* number of transparency values */

   png_byte chunk_name[5];    /* null-terminated name of current chunk */

   png_byte compression;      /* file compression type (always 0) */

   png_byte filter;           /* file filter type (always 0) */

   png_byte interlaced;       /* PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */

   png_byte pass;             /* current interlace pass (0 - 6) */

   png_byte do_filter;        /* row filter flags (see PNG_FILTER_ below ) */

   png_byte color_type;       /* color type of file */

   png_byte bit_depth;        /* bit depth of file */

   png_byte usr_bit_depth;    /* bit depth of users row */

   png_byte pixel_depth;      /* number of bits per pixel */

   png_byte channels;         /* number of channels in file */

   png_byte usr_channels;     /* channels at start of write */

   png_byte sig_bytes;        /* magic bytes read/written from start of file */



#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)

#ifdef PNG_LEGACY_SUPPORTED

   png_byte filler;           /* filler byte for pixel expansion */

#else

   png_uint_16 filler;           /* filler bytes for pixel expansion */

#endif

#endif



#if defined(PNG_bKGD_SUPPORTED)

   png_byte background_gamma_type;

#  ifdef PNG_FLOATING_POINT_SUPPORTED

   float background_gamma;

#  endif

   png_color_16 background;   /* background color in screen gamma space */

#if defined(PNG_READ_GAMMA_SUPPORTED)

   png_color_16 background_1; /* background normalized to gamma 1.0 */

#endif

#endif /* PNG_bKGD_SUPPORTED */



#if defined(PNG_WRITE_FLUSH_SUPPORTED)

   png_flush_ptr output_flush_fn;/* Function for flushing output */

   png_uint_32 flush_dist;    /* how many rows apart to flush, 0 - no flush */

   png_uint_32 flush_rows;    /* number of rows written since last flush */

#endif



#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)

   int gamma_shift;      /* number of "insignificant" bits 16-bit gamma */

#ifdef PNG_FLOATING_POINT_SUPPORTED

   float gamma;          /* file gamma value */

   float screen_gamma;   /* screen gamma value (display_exponent) */

#endif

#endif



#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)

   png_bytep gamma_table;     /* gamma table for 8-bit depth files */

   png_bytep gamma_from_1;    /* converts from 1.0 to screen */

   png_bytep gamma_to_1;      /* converts from file to 1.0 */

   png_uint_16pp gamma_16_table; /* gamma table for 16-bit depth files */

   png_uint_16pp gamma_16_from_1; /* converts from 1.0 to screen */

   png_uint_16pp gamma_16_to_1; /* converts from file to 1.0 */

#endif



#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_sBIT_SUPPORTED)

   png_color_8 sig_bit;       /* significant bits in each available channel */

#endif



#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)

   png_color_8 shift;         /* shift for significant bit tranformation */

#endif



#if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) \

 || defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)

   png_bytep trans;           /* transparency values for paletted files */

   png_color_16 trans_values; /* transparency values for non-paletted files */

#endif



   png_read_status_ptr read_row_fn;   /* called after each row is decoded */

   png_write_status_ptr write_row_fn; /* called after each row is encoded */

#ifdef PNG_PROGRESSIVE_READ_SUPPORTED

   png_progressive_info_ptr info_fn; /* called after header data fully read */

   png_progressive_row_ptr row_fn;   /* called after each prog. row is decoded */

   png_progressive_end_ptr end_fn;   /* called after image is complete */

   png_bytep save_buffer_ptr;        /* current location in save_buffer */

   png_bytep save_buffer;            /* buffer for previously read data */

   png_bytep current_buffer_ptr;     /* current location in current_buffer */

   png_bytep current_buffer;         /* buffer for recently used data */

   png_uint_32 push_length;          /* size of current input chunk */

   png_uint_32 skip_length;          /* bytes to skip in input data */

   png_size_t save_buffer_size;      /* amount of data now in save_buffer */

   png_size_t save_buffer_max;       /* total size of save_buffer */

   png_size_t buffer_size;           /* total amount of available input data */

   png_size_t current_buffer_size;   /* amount of data now in current_buffer */

   int process_mode;                 /* what push library is currently doing */

   int cur_palette;                  /* current push library palette index */



#  if defined(PNG_TEXT_SUPPORTED)

     png_size_t current_text_size;   /* current size of text input data */

     png_size_t current_text_left;   /* how much text left to read in input */

     png_charp current_text;         /* current text chunk buffer */

     png_charp current_text_ptr;     /* current location in current_text */

#  endif /* PNG_PROGRESSIVE_READ_SUPPORTED && PNG_TEXT_SUPPORTED */



#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */



#if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)

/* for the Borland special 64K segment handler */

   png_bytepp offset_table_ptr;

   png_bytep offset_table;

   png_uint_16 offset_table_number;

   png_uint_16 offset_table_count;

   png_uint_16 offset_table_count_free;

#endif



#if defined(PNG_READ_DITHER_SUPPORTED)

   png_bytep palette_lookup;         /* lookup table for dithering */

   png_bytep dither_index;           /* index translation for palette files */

#endif



#if defined(PNG_READ_DITHER_SUPPORTED) || defined(PNG_hIST_SUPPORTED)

   png_uint_16p hist;                /* histogram */

#endif



#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)

   png_byte heuristic_method;        /* heuristic for row filter selection */

   png_byte num_prev_filters;        /* number of weights for previous rows */

   png_bytep prev_filters;           /* filter type(s) of previous row(s) */

   png_uint_16p filter_weights;      /* weight(s) for previous line(s) */

   png_uint_16p inv_filter_weights;  /* 1/weight(s) for previous line(s) */

   png_uint_16p filter_costs;        /* relative filter calculation cost */

   png_uint_16p inv_filter_costs;    /* 1/relative filter calculation cost */

#endif



#if defined(PNG_TIME_RFC1123_SUPPORTED)

   png_charp time_buffer;            /* String to hold RFC 1123 time text */

#endif



/* New members added in libpng-1.0.6 */



#ifdef PNG_FREE_ME_SUPPORTED

   png_uint_32 free_me;       /* flags items libpng is responsible for freeing */

#endif



#if defined(PNG_USER_CHUNKS_SUPPORTED)

   png_voidp user_chunk_ptr;

   png_user_chunk_ptr read_user_chunk_fn; /* user read chunk handler */

#endif



#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)

   int num_chunk_list;

   png_bytep chunk_list;

#endif



/* New members added in libpng-1.0.3 */

#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)

   png_byte rgb_to_gray_status;

   /* These were changed from png_byte in libpng-1.0.6 */

   png_uint_16 rgb_to_gray_red_coeff;

   png_uint_16 rgb_to_gray_green_coeff;

   png_uint_16 rgb_to_gray_blue_coeff;

#endif



/* New member added in libpng-1.0.4 (renamed in 1.0.9) */

#if defined(PNG_MNG_FEATURES_SUPPORTED) || \

    defined(PNG_READ_EMPTY_PLTE_SUPPORTED) || \

    defined(PNG_WRITE_EMPTY_PLTE_SUPPORTED)

/* changed from png_byte to png_uint_32 at version 1.2.0 */

#ifdef PNG_1_0_X

   png_byte mng_features_permitted;

#else

   png_uint_32 mng_features_permitted;

#endif /* PNG_1_0_X */

#endif



/* New member added in libpng-1.0.7 */

#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)

   png_fixed_point int_gamma;

#endif



/* New member added in libpng-1.0.9, ifdef'ed out in 1.0.12, enabled in 1.2.0 */

#if defined(PNG_MNG_FEATURES_SUPPORTED)

   png_byte filter_type;

#endif



#if defined(PNG_1_0_X) || (defined(PNG_DEBUG) && defined(PNG_USE_PNGGCCRD))

/* New member added in libpng-1.0.10, ifdef'ed out in 1.2.0 */

   png_uint_32 row_buf_size;

#endif



/* New members added in libpng-1.2.0 */

#if !defined(PNG_1_0_X) && defined(PNG_ASSEMBLER_CODE_SUPPORTED)

   png_byte     mmx_bitdepth_threshold;

   png_uint_32  mmx_rowbytes_threshold;

   png_uint_32  asm_flags;

#endif



/* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */

#ifdef PNG_USER_MEM_SUPPORTED

   png_voidp mem_ptr;                /* user supplied struct for mem functions */

   png_malloc_ptr malloc_fn;         /* function for allocating memory */

   png_free_ptr free_fn;             /* function for freeing memory */

#endif



/* New member added in libpng-1.0.13 and 1.2.0 */

   png_bytep big_row_buf;         /* buffer to save current (unfiltered) row */



#if defined(PNG_READ_DITHER_SUPPORTED)

/* The following three members were added at version 1.0.14 and 1.2.4 */

   png_bytep dither_sort;            /* working sort array */

   png_bytep index_to_palette;       /* where the original index currently is */

                                     /* in the palette */

   png_bytep palette_to_index;       /* which original index points to this */

                                     /* palette color */

#endif



/* New members added in libpng-1.0.16 and 1.2.6 */

   png_byte compression_type;



#ifdef PNG_SET_USER_LIMITS_SUPPORTED

   png_uint_32 user_width_max;

   png_uint_32 user_height_max;

#endif



};





/* This triggers a compiler error in png.c, if png.c and png.h

 * do not agree upon the version number.

 */

typedef png_structp version_1_2_7;



typedef png_struct FAR * FAR * png_structpp;



/* Here are the function definitions most commonly used.  This is not

 * the place to find out how to use libpng.  See libpng.txt for the

 * full explanation, see example.c for the summary.  This just provides

 * a simple one line description of the use of each function.

 */



/* Returns the version number of the library */

extern PNG_EXPORT(png_uint_32,png_access_version_number) PNGARG((void));



/* Tell lib we have already handled the first <num_bytes> magic bytes.

 * Handling more than 8 bytes from the beginning of the file is an error.

 */

extern PNG_EXPORT(void,png_set_sig_bytes) PNGARG((png_structp png_ptr,

   int num_bytes));



/* Check sig[start] through sig[start + num_to_check - 1] to see if it's a

 * PNG file.  Returns zero if the supplied bytes match the 8-byte PNG

 * signature, and non-zero otherwise.  Having num_to_check == 0 or

 * start > 7 will always fail (ie return non-zero).

 */

extern PNG_EXPORT(int,png_sig_cmp) PNGARG((png_bytep sig, png_size_t start,

   png_size_t num_to_check));



/* Simple signature checking function.  This is the same as calling

 * png_check_sig(sig, n) := !png_sig_cmp(sig, 0, n).

 */

extern PNG_EXPORT(int,png_check_sig) PNGARG((png_bytep sig, int num));



/* Allocate and initialize png_ptr struct for reading, and any other memory. */

extern PNG_EXPORT(png_structp,png_create_read_struct)

   PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,

   png_error_ptr error_fn, png_error_ptr warn_fn));



/* Allocate and initialize png_ptr struct for writing, and any other memory */

extern PNG_EXPORT(png_structp,png_create_write_struct)

   PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,

   png_error_ptr error_fn, png_error_ptr warn_fn));



#ifdef PNG_WRITE_SUPPORTED

extern PNG_EXPORT(png_uint_32,png_get_compression_buffer_size)

   PNGARG((png_structp png_ptr));

#endif



#ifdef PNG_WRITE_SUPPORTED

extern PNG_EXPORT(void,png_set_compression_buffer_size)

   PNGARG((png_structp png_ptr, png_uint_32 size));

#endif



/* Reset the compression stream */

extern PNG_EXPORT(int,png_reset_zstream) PNGARG((png_structp png_ptr));



/* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */

#ifdef PNG_USER_MEM_SUPPORTED

extern PNG_EXPORT(png_structp,png_create_read_struct_2)

   PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,

   png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,

   png_malloc_ptr malloc_fn, png_free_ptr free_fn));

extern PNG_EXPORT(png_structp,png_create_write_struct_2)

   PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,

   png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,

   png_malloc_ptr malloc_fn, png_free_ptr free_fn));

#endif



/* Write a PNG chunk - size, type, (optional) data, CRC. */

extern PNG_EXPORT(void,png_write_chunk) PNGARG((png_structp png_ptr,

   png_bytep chunk_name, png_bytep data, png_size_t length));



/* Write the start of a PNG chunk - length and chunk name. */

extern PNG_EXPORT(void,png_write_chunk_start) PNGARG((png_structp png_ptr,

   png_bytep chunk_name, png_uint_32 length));



/* Write the data of a PNG chunk started with png_write_chunk_start(). */

extern PNG_EXPORT(void,png_write_chunk_data) PNGARG((png_structp png_ptr,

   png_bytep data, png_size_t length));



/* Finish a chunk started with png_write_chunk_start() (includes CRC). */

extern PNG_EXPORT(void,png_write_chunk_end) PNGARG((png_structp png_ptr));



/* Allocate and initialize the info structure */

extern PNG_EXPORT(png_infop,png_create_info_struct)

   PNGARG((png_structp png_ptr));



/* Initialize the info structure (old interface - DEPRECATED) */

extern PNG_EXPORT(void,png_info_init) PNGARG((png_infop info_ptr));

#undef png_info_init

#define png_info_init(info_ptr) png_info_init_3(&info_ptr,\

    png_sizeof(png_info));

extern PNG_EXPORT(void,png_info_init_3) PNGARG((png_infopp info_ptr,

    png_size_t png_info_struct_size));



/* Writes all the PNG information before the image. */

extern PNG_EXPORT(void,png_write_info_before_PLTE) PNGARG((png_structp png_ptr,

   png_infop info_ptr));

extern PNG_EXPORT(void,png_write_info) PNGARG((png_structp png_ptr,

   png_infop info_ptr));



#ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED

/* read the information before the actual image data. */

extern PNG_EXPORT(void,png_read_info) PNGARG((png_structp png_ptr,

   png_infop info_ptr));

#endif



#if defined(PNG_TIME_RFC1123_SUPPORTED)

extern PNG_EXPORT(png_charp,png_convert_to_rfc1123)

   PNGARG((png_structp png_ptr, png_timep ptime));

#endif



#if !defined(_WIN32_WCE)

/* "time.h" functions are not supported on WindowsCE */

#if defined(PNG_WRITE_tIME_SUPPORTED)

/* convert from a struct tm to png_time */

extern PNG_EXPORT(void,png_convert_from_struct_tm) PNGARG((png_timep ptime,

   struct tm FAR * ttime));



/* convert from time_t to png_time.  Uses gmtime() */

extern PNG_EXPORT(void,png_convert_from_time_t) PNGARG((png_timep ptime,

   time_t ttime));

#endif /* PNG_WRITE_tIME_SUPPORTED */

#endif /* _WIN32_WCE */



#if defined(PNG_READ_EXPAND_SUPPORTED)

/* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */

extern PNG_EXPORT(void,png_set_expand) PNGARG((png_structp png_ptr));

extern PNG_EXPORT(void,png_set_gray_1_2_4_to_8) PNGARG((png_structp png_ptr));

extern PNG_EXPORT(void,png_set_palette_to_rgb) PNGARG((png_structp png_ptr));

extern PNG_EXPORT(void,png_set_tRNS_to_alpha) PNGARG((png_structp png_ptr));

#endif



#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)

/* Use blue, green, red order for pixels. */

extern PNG_EXPORT(void,png_set_bgr) PNGARG((png_structp png_ptr));

#endif



#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)

/* Expand the grayscale to 24-bit RGB if necessary. */

extern PNG_EXPORT(void,png_set_gray_to_rgb) PNGARG((png_structp png_ptr));

#endif



#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)

/* Reduce RGB to grayscale. */

#ifdef PNG_FLOATING_POINT_SUPPORTED

extern PNG_EXPORT(void,png_set_rgb_to_gray) PNGARG((png_structp png_ptr,

   int error_action, double red, double green ));

#endif

extern PNG_EXPORT(void,png_set_rgb_to_gray_fixed) PNGARG((png_structp png_ptr,

   int error_action, png_fixed_point red, png_fixed_point green ));

extern PNG_EXPORT(png_byte,png_get_rgb_to_gray_status) PNGARG((png_structp

   png_ptr));

#endif



extern PNG_EXPORT(void,png_build_grayscale_palette) PNGARG((int bit_depth,

   png_colorp palette));



#if defined(PNG_READ_STRIP_ALPHA_SUPPORTED)

extern PNG_EXPORT(void,png_set_strip_alpha) PNGARG((png_structp png_ptr));

#endif



#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \

    defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)

extern PNG_EXPORT(void,png_set_swap_alpha) PNGARG((png_structp png_ptr));

#endif



#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \

    defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)

extern PNG_EXPORT(void,png_set_invert_alpha) PNGARG((png_structp png_ptr));

#endif



#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)

/* Add a filler byte to 8-bit Gray or 24-bit RGB images. */

extern PNG_EXPORT(void,png_set_filler) PNGARG((png_structp png_ptr,

   png_uint_32 filler, int flags));

/* The values of the PNG_FILLER_ defines should NOT be changed */

#define PNG_FILLER_BEFORE 0

#define PNG_FILLER_AFTER 1

/* Add an alpha byte to 8-bit Gray or 24-bit RGB images. */

#if !defined(PNG_1_0_X)

extern PNG_EXPORT(void,png_set_add_alpha) PNGARG((png_structp png_ptr,

   png_uint_32 filler, int flags));

#endif

#endif /* PNG_READ_FILLER_SUPPORTED || PNG_WRITE_FILLER_SUPPORTED */



#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)

/* Swap bytes in 16-bit depth files. */

extern PNG_EXPORT(void,png_set_swap) PNGARG((png_structp png_ptr));

#endif



#if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)

/* Use 1 byte per pixel in 1, 2, or 4-bit depth files. */

extern PNG_EXPORT(void,png_set_packing) PNGARG((png_structp png_ptr));

#endif



#if defined(PNG_READ_PACKSWAP_SUPPORTED) || defined(PNG_WRITE_PACKSWAP_SUPPORTED)

/* Swap packing order of pixels in bytes. */

extern PNG_EXPORT(void,png_set_packswap) PNGARG((png_structp png_ptr));

#endif



#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)

/* Converts files to legal bit depths. */

extern PNG_EXPORT(void,png_set_shift) PNGARG((png_structp png_ptr,

   png_color_8p true_bits));

#endif



#if defined(PNG_READ_INTERLACING_SUPPORTED) || \

    defined(PNG_WRITE_INTERLACING_SUPPORTED)

/* Have the code handle the interlacing.  Returns the number of passes. */

extern PNG_EXPORT(int,png_set_interlace_handling) PNGARG((png_structp png_ptr));

#endif



#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)

/* Invert monochrome files */

extern PNG_EXPORT(void,png_set_invert_mono) PNGARG((png_structp png_ptr));

#endif



#if defined(PNG_READ_BACKGROUND_SUPPORTED)

/* Handle alpha and tRNS by replacing with a background color. */

#ifdef PNG_FLOATING_POINT_SUPPORTED

extern PNG_EXPORT(void,png_set_background) PNGARG((png_structp png_ptr,

   png_color_16p background_color, int background_gamma_code,

   int need_expand, double background_gamma));

#endif

#define PNG_BACKGROUND_GAMMA_UNKNOWN 0

#define PNG_BACKGROUND_GAMMA_SCREEN  1

#define PNG_BACKGROUND_GAMMA_FILE    2

#define PNG_BACKGROUND_GAMMA_UNIQUE  3

#endif



#if defined(PNG_READ_16_TO_8_SUPPORTED)

/* strip the second byte of information from a 16-bit depth file. */

extern PNG_EXPORT(void,png_set_strip_16) PNGARG((png_structp png_ptr));

#endif



#if defined(PNG_READ_DITHER_SUPPORTED)

/* Turn on dithering, and reduce the palette to the number of colors available. */

extern PNG_EXPORT(void,png_set_dither) PNGARG((png_structp png_ptr,

   png_colorp palette, int num_palette, int maximum_colors,

   png_uint_16p histogram, int full_dither));

#endif



#if defined(PNG_READ_GAMMA_SUPPORTED)

/* Handle gamma correction. Screen_gamma=(display_exponent) */

#ifdef PNG_FLOATING_POINT_SUPPORTED

extern PNG_EXPORT(void,png_set_gamma) PNGARG((png_structp png_ptr,

   double screen_gamma, double default_file_gamma));

#endif

#endif



#if defined(PNG_READ_EMPTY_PLTE_SUPPORTED) || \

    defined(PNG_WRITE_EMPTY_PLTE_SUPPORTED)

/* Permit or disallow empty PLTE (0: not permitted, 1: permitted) */

/* Deprecated and will be removed.  Use png_permit_mng_features() instead. */

extern PNG_EXPORT(void,png_permit_empty_plte) PNGARG((png_structp png_ptr,

   int empty_plte_permitted));

#endif



#if defined(PNG_WRITE_FLUSH_SUPPORTED)

/* Set how many lines between output flushes - 0 for no flushing */

extern PNG_EXPORT(void,png_set_flush) PNGARG((png_structp png_ptr, int nrows));

/* Flush the current PNG output buffer */

extern PNG_EXPORT(void,png_write_flush) PNGARG((png_structp png_ptr));

#endif



/* optional update palette with requested transformations */

extern PNG_EXPORT(void,png_start_read_image) PNGARG((png_structp png_ptr));



/* optional call to update the users info structure */

extern PNG_EXPORT(void,png_read_update_info) PNGARG((png_structp png_ptr,

   png_infop info_ptr));



#ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED

/* read one or more rows of image data. */

extern PNG_EXPORT(void,png_read_rows) PNGARG((png_structp png_ptr,

   png_bytepp row, png_bytepp display_row, png_uint_32 num_rows));

#endif



#ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED

/* read a row of data. */

extern PNG_EXPORT(void,png_read_row) PNGARG((png_structp png_ptr,

   png_bytep row,

   png_bytep display_row));

#endif



#ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED

/* read the whole image into memory at once. */

extern PNG_EXPORT(void,png_read_image) PNGARG((png_structp png_ptr,

   png_bytepp image));

#endif



/* write a row of image data */

extern PNG_EXPORT(void,png_write_row) PNGARG((png_structp png_ptr,

   png_bytep row));



/* write a few rows of image data */

extern PNG_EXPORT(void,png_write_rows) PNGARG((png_structp png_ptr,

   png_bytepp row, png_uint_32 num_rows));



/* write the image data */

extern PNG_EXPORT(void,png_write_image) PNGARG((png_structp png_ptr,

   png_bytepp image));



/* writes the end of the PNG file. */

extern PNG_EXPORT(void,png_write_end) PNGARG((png_structp png_ptr,

   png_infop info_ptr));



#ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED

/* read the end of the PNG file. */

extern PNG_EXPORT(void,png_read_end) PNGARG((png_structp png_ptr,

   png_infop info_ptr));

#endif



/* free any memory associated with the png_info_struct */

extern PNG_EXPORT(void,png_destroy_info_struct) PNGARG((png_structp png_ptr,

   png_infopp info_ptr_ptr));



/* free any memory associated with the png_struct and the png_info_structs */

extern PNG_EXPORT(void,png_destroy_read_struct) PNGARG((png_structpp

   png_ptr_ptr, png_infopp info_ptr_ptr, png_infopp end_info_ptr_ptr));



/* free all memory used by the read (old method - NOT DLL EXPORTED) */

extern void png_read_destroy PNGARG((png_structp png_ptr, png_infop info_ptr,

   png_infop end_info_ptr));



/* free any memory associated with the png_struct and the png_info_structs */

extern PNG_EXPORT(void,png_destroy_write_struct)

   PNGARG((png_structpp png_ptr_ptr, png_infopp info_ptr_ptr));



/* free any memory used in png_ptr struct (old method - NOT DLL EXPORTED) */

extern void png_write_destroy PNGARG((png_structp png_ptr));



/* set the libpng method of handling chunk CRC errors */

extern PNG_EXPORT(void,png_set_crc_action) PNGARG((png_structp png_ptr,

   int crit_action, int ancil_action));



/* Values for png_set_crc_action() to say how to handle CRC errors in

 * ancillary and critical chunks, and whether to use the data contained

 * therein.  Note that it is impossible to "discard" data in a critical

 * chunk.  For versions prior to 0.90, the action was always error/quit,

 * whereas in version 0.90 and later, the action for CRC errors in ancillary

 * chunks is warn/discard.  These values should NOT be changed.

 *

 *      value                       action:critical     action:ancillary

 */

#define PNG_CRC_DEFAULT       0  /* error/quit          warn/discard data */

#define PNG_CRC_ERROR_QUIT    1  /* error/quit          error/quit        */

#define PNG_CRC_WARN_DISCARD  2  /* (INVALID)           warn/discard data */

#define PNG_CRC_WARN_USE      3  /* warn/use data       warn/use data     */

#define PNG_CRC_QUIET_USE     4  /* quiet/use data      quiet/use data    */

#define PNG_CRC_NO_CHANGE     5  /* use current value   use current value */



/* These functions give the user control over the scan-line filtering in

 * libpng and the compression methods used by zlib.  These functions are

 * mainly useful for testing, as the defaults should work with most users.

 * Those users who are tight on memory or want faster performance at the

 * expense of compression can modify them.  See the compression library

 * header file (zlib.h) for an explination of the compression functions.

 */



/* set the filtering method(s) used by libpng.  Currently, the only valid

 * value for "method" is 0.

 */

extern PNG_EXPORT(void,png_set_filter) PNGARG((png_structp png_ptr, int method,

   int filters));



/* Flags for png_set_filter() to say which filters to use.  The flags

 * are chosen so that they don't conflict with real filter types

 * below, in case they are supplied instead of the #defined constants.

 * These values should NOT be changed.

 */

#define PNG_NO_FILTERS     0x00

#define PNG_FILTER_NONE    0x08

#define PNG_FILTER_SUB     0x10

#define PNG_FILTER_UP      0x20

#define PNG_FILTER_AVG     0x40

#define PNG_FILTER_PAETH   0x80

#define PNG_ALL_FILTERS (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP | \

                         PNG_FILTER_AVG | PNG_FILTER_PAETH)



/* Filter values (not flags) - used in pngwrite.c, pngwutil.c for now.

 * These defines should NOT be changed.

 */

#define PNG_FILTER_VALUE_NONE  0

#define PNG_FILTER_VALUE_SUB   1

#define PNG_FILTER_VALUE_UP    2

#define PNG_FILTER_VALUE_AVG   3

#define PNG_FILTER_VALUE_PAETH 4

#define PNG_FILTER_VALUE_LAST  5



#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED) /* EXPERIMENTAL */

/* The "heuristic_method" is given by one of the PNG_FILTER_HEURISTIC_

 * defines, either the default (minimum-sum-of-absolute-differences), or

 * the experimental method (weighted-minimum-sum-of-absolute-differences).

 *

 * Weights are factors >= 1.0, indicating how important it is to keep the

 * filter type consistent between rows.  Larger numbers mean the current

 * filter is that many times as likely to be the same as the "num_weights"

 * previous filters.  This is cumulative for each previous row with a weight.

 * There needs to be "num_weights" values in "filter_weights", or it can be

 * NULL if the weights aren't being specified.  Weights have no influence on

 * the selection of the first row filter.  Well chosen weights can (in theory)

 * improve the compression for a given image.

 *

 * Costs are factors >= 1.0 indicating the relative decoding costs of a

 * filter type.  Higher costs indicate more decoding expense, and are

 * therefore less likely to be selected over a filter with lower computational

 * costs.  There needs to be a value in "filter_costs" for each valid filter

 * type (given by PNG_FILTER_VALUE_LAST), or it can be NULL if you aren't

 * setting the costs.  Costs try to improve the speed of decompression without

 * unduly increasing the compressed image size.

 *

 * A negative weight or cost indicates the default value is to be used, and

 * values in the range [0.0, 1.0) indicate the value is to remain unchanged.

 * The default values for both weights and costs are currently 1.0, but may

 * change if good general weighting/cost heuristics can be found.  If both

 * the weights and costs are set to 1.0, this degenerates the WEIGHTED method

 * to the UNWEIGHTED method, but with added encoding time/computation.

 */

#ifdef PNG_FLOATING_POINT_SUPPORTED

extern PNG_EXPORT(void,png_set_filter_heuristics) PNGARG((png_structp png_ptr,

   int heuristic_method, int num_weights, png_doublep filter_weights,

   png_doublep filter_costs));

#endif

#endif /*  PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */



/* Heuristic used for row filter selection.  These defines should NOT be

 * changed.

 */

#define PNG_FILTER_HEURISTIC_DEFAULT    0  /* Currently "UNWEIGHTED" */

#define PNG_FILTER_HEURISTIC_UNWEIGHTED 1  /* Used by libpng < 0.95 */

#define PNG_FILTER_HEURISTIC_WEIGHTED   2  /* Experimental feature */

#define PNG_FILTER_HEURISTIC_LAST       3  /* Not a valid value */



/* Set the library compression level.  Currently, valid values range from

 * 0 - 9, corresponding directly to the zlib compression levels 0 - 9

 * (0 - no compression, 9 - "maximal" compression).  Note that tests have

 * shown that zlib compression levels 3-6 usually perform as well as level 9

 * for PNG images, and do considerably fewer caclulations.  In the future,

 * these values may not correspond directly to the zlib compression levels.

 */

extern PNG_EXPORT(void,png_set_compression_level) PNGARG((png_structp png_ptr,

   int level));



extern PNG_EXPORT(void,png_set_compression_mem_level)

   PNGARG((png_structp png_ptr, int mem_level));



extern PNG_EXPORT(void,png_set_compression_strategy)

   PNGARG((png_structp png_ptr, int strategy));



extern PNG_EXPORT(void,png_set_compression_window_bits)

   PNGARG((png_structp png_ptr, int window_bits));



extern PNG_EXPORT(void,png_set_compression_method) PNGARG((png_structp png_ptr,

   int method));



/* These next functions are called for input/output, memory, and error

 * handling.  They are in the file pngrio.c, pngwio.c, and pngerror.c,

 * and call standard C I/O routines such as fread(), fwrite(), and

 * fprintf().  These functions can be made to use other I/O routines

 * at run time for those applications that need to handle I/O in a

 * different manner by calling png_set_???_fn().  See libpng.txt for

 * more information.

 */



#if !defined(PNG_NO_STDIO)

/* Initialize the input/output for the PNG file to the default functions. */

extern PNG_EXPORT(void,png_init_io) PNGARG((png_structp png_ptr, png_FILE_p fp));

#endif



/* Replace the (error and abort), and warning functions with user

 * supplied functions.  If no messages are to be printed you must still

 * write and use replacement functions. The replacement error_fn should

 * still do a longjmp to the last setjmp location if you are using this

 * method of error handling.  If error_fn or warning_fn is NULL, the

 * default function will be used.

 */



extern PNG_EXPORT(void,png_set_error_fn) PNGARG((png_structp png_ptr,

   png_voidp error_ptr, png_error_ptr error_fn, png_error_ptr warning_fn));



/* Return the user pointer associated with the error functions */

extern PNG_EXPORT(png_voidp,png_get_error_ptr) PNGARG((png_structp png_ptr));



/* Replace the default data output functions with a user supplied one(s).

 * If buffered output is not used, then output_flush_fn can be set to NULL.

 * If PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile time

 * output_flush_fn will be ignored (and thus can be NULL).

 */

extern PNG_EXPORT(void,png_set_write_fn) PNGARG((png_structp png_ptr,

   png_voidp io_ptr, png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn));



/* Replace the default data input function with a user supplied one. */

extern PNG_EXPORT(void,png_set_read_fn) PNGARG((png_structp png_ptr,

   png_voidp io_ptr, png_rw_ptr read_data_fn));



/* Return the user pointer associated with the I/O functions */

extern PNG_EXPORT(png_voidp,png_get_io_ptr) PNGARG((png_structp png_ptr));



extern PNG_EXPORT(void,png_set_read_status_fn) PNGARG((png_structp png_ptr,

   png_read_status_ptr read_row_fn));



extern PNG_EXPORT(void,png_set_write_status_fn) PNGARG((png_structp png_ptr,

   png_write_status_ptr write_row_fn));



#ifdef PNG_USER_MEM_SUPPORTED

/* Replace the default memory allocation functions with user supplied one(s). */

extern PNG_EXPORT(void,png_set_mem_fn) PNGARG((png_structp png_ptr,

   png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn));

/* Return the user pointer associated with the memory functions */

extern PNG_EXPORT(png_voidp,png_get_mem_ptr) PNGARG((png_structp png_ptr));

#endif



#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \

    defined(PNG_LEGACY_SUPPORTED)

extern PNG_EXPORT(void,png_set_read_user_transform_fn) PNGARG((png_structp

   png_ptr, png_user_transform_ptr read_user_transform_fn));

#endif



#if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) || \

    defined(PNG_LEGACY_SUPPORTED)

extern PNG_EXPORT(void,png_set_write_user_transform_fn) PNGARG((png_structp

   png_ptr, png_user_transform_ptr write_user_transform_fn));

#endif



#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \

    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) || \

    defined(PNG_LEGACY_SUPPORTED)

extern PNG_EXPORT(void,png_set_user_transform_info) PNGARG((png_structp

   png_ptr, png_voidp user_transform_ptr, int user_transform_depth,

   int user_transform_channels));

/* Return the user pointer associated with the user transform functions */

extern PNG_EXPORT(png_voidp,png_get_user_transform_ptr)

   PNGARG((png_structp png_ptr));

#endif



#ifdef PNG_USER_CHUNKS_SUPPORTED

extern PNG_EXPORT(void,png_set_read_user_chunk_fn) PNGARG((png_structp png_ptr,

   png_voidp user_chunk_ptr, png_user_chunk_ptr read_user_chunk_fn));

extern PNG_EXPORT(png_voidp,png_get_user_chunk_ptr) PNGARG((png_structp

   png_ptr));

#endif



#ifdef PNG_PROGRESSIVE_READ_SUPPORTED

/* Sets the function callbacks for the push reader, and a pointer to a

 * user-defined structure available to the callback functions.

 */

extern PNG_EXPORT(void,png_set_progressive_read_fn) PNGARG((png_structp png_ptr,

   png_voidp progressive_ptr,

   png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,

   png_progressive_end_ptr end_fn));



/* returns the user pointer associated with the push read functions */

extern PNG_EXPORT(png_voidp,png_get_progressive_ptr)

   PNGARG((png_structp png_ptr));



/* function to be called when data becomes available */

extern PNG_EXPORT(void,png_process_data) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_bytep buffer, png_size_t buffer_size));



/* function that combines rows.  Not very much different than the

 * png_combine_row() call.  Is this even used?????

 */

extern PNG_EXPORT(void,png_progressive_combine_row) PNGARG((png_structp png_ptr,

   png_bytep old_row, png_bytep new_row));

#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */



extern PNG_EXPORT(png_voidp,png_malloc) PNGARG((png_structp png_ptr,

   png_uint_32 size));



#if defined(PNG_1_0_X)

#  define png_malloc_warn png_malloc

#else

/* Added at libpng version 1.2.4 */

extern PNG_EXPORT(png_voidp,png_malloc_warn) PNGARG((png_structp png_ptr,

   png_uint_32 size));

#endif



/* frees a pointer allocated by png_malloc() */

extern PNG_EXPORT(void,png_free) PNGARG((png_structp png_ptr, png_voidp ptr));



#if defined(PNG_1_0_X)

/* Function to allocate memory for zlib. */

extern PNG_EXPORT(voidpf,png_zalloc) PNGARG((voidpf png_ptr, uInt items,

   uInt size));



/* Function to free memory for zlib */

extern PNG_EXPORT(void,png_zfree) PNGARG((voidpf png_ptr, voidpf ptr));

#endif



/* Free data that was allocated internally */

extern PNG_EXPORT(void,png_free_data) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_uint_32 free_me, int num));

#ifdef PNG_FREE_ME_SUPPORTED

/* Reassign responsibility for freeing existing data, whether allocated

 * by libpng or by the application */

extern PNG_EXPORT(void,png_data_freer) PNGARG((png_structp png_ptr,

   png_infop info_ptr, int freer, png_uint_32 mask));

#endif

/* assignments for png_data_freer */

#define PNG_DESTROY_WILL_FREE_DATA 1

#define PNG_SET_WILL_FREE_DATA 1

#define PNG_USER_WILL_FREE_DATA 2

/* Flags for png_ptr->free_me and info_ptr->free_me */

#define PNG_FREE_HIST 0x0008

#define PNG_FREE_ICCP 0x0010

#define PNG_FREE_SPLT 0x0020

#define PNG_FREE_ROWS 0x0040

#define PNG_FREE_PCAL 0x0080

#define PNG_FREE_SCAL 0x0100

#define PNG_FREE_UNKN 0x0200

#define PNG_FREE_LIST 0x0400

#define PNG_FREE_PLTE 0x1000

#define PNG_FREE_TRNS 0x2000

#define PNG_FREE_TEXT 0x4000

#define PNG_FREE_ALL  0x7fff

#define PNG_FREE_MUL  0x4220 /* PNG_FREE_SPLT|PNG_FREE_TEXT|PNG_FREE_UNKN */



#ifdef PNG_USER_MEM_SUPPORTED

extern PNG_EXPORT(png_voidp,png_malloc_default) PNGARG((png_structp png_ptr,

   png_uint_32 size));

extern PNG_EXPORT(void,png_free_default) PNGARG((png_structp png_ptr,

   png_voidp ptr));

#endif



extern PNG_EXPORT(png_voidp,png_memcpy_check) PNGARG((png_structp png_ptr,

   png_voidp s1, png_voidp s2, png_uint_32 size));



extern PNG_EXPORT(png_voidp,png_memset_check) PNGARG((png_structp png_ptr,

   png_voidp s1, int value, png_uint_32 size));



#if defined(USE_FAR_KEYWORD)  /* memory model conversion function */

extern void *png_far_to_near PNGARG((png_structp png_ptr,png_voidp ptr,

   int check));

#endif /* USE_FAR_KEYWORD */



/* Fatal error in PNG image of libpng - can't continue */

extern PNG_EXPORT(void,png_error) PNGARG((png_structp png_ptr,

   png_const_charp error_message));



/* The same, but the chunk name is prepended to the error string. */

extern PNG_EXPORT(void,png_chunk_error) PNGARG((png_structp png_ptr,

   png_const_charp error_message));



/* Non-fatal error in libpng.  Can continue, but may have a problem. */

extern PNG_EXPORT(void,png_warning) PNGARG((png_structp png_ptr,

   png_const_charp warning_message));



/* Non-fatal error in libpng, chunk name is prepended to message. */

extern PNG_EXPORT(void,png_chunk_warning) PNGARG((png_structp png_ptr,

   png_const_charp warning_message));



/* The png_set_<chunk> functions are for storing values in the png_info_struct.

 * Similarly, the png_get_<chunk> calls are used to read values from the

 * png_info_struct, either storing the parameters in the passed variables, or

 * setting pointers into the png_info_struct where the data is stored.  The

 * png_get_<chunk> functions return a non-zero value if the data was available

 * in info_ptr, or return zero and do not change any of the parameters if the

 * data was not available.

 *

 * These functions should be used instead of directly accessing png_info

 * to avoid problems with future changes in the size and internal layout of

 * png_info_struct.

 */

/* Returns "flag" if chunk data is valid in info_ptr. */

extern PNG_EXPORT(png_uint_32,png_get_valid) PNGARG((png_structp png_ptr,

png_infop info_ptr, png_uint_32 flag));



/* Returns number of bytes needed to hold a transformed row. */

extern PNG_EXPORT(png_uint_32,png_get_rowbytes) PNGARG((png_structp png_ptr,

png_infop info_ptr));



#if defined(PNG_INFO_IMAGE_SUPPORTED)

/* Returns row_pointers, which is an array of pointers to scanlines that was

returned from png_read_png(). */

extern PNG_EXPORT(png_bytepp,png_get_rows) PNGARG((png_structp png_ptr,

png_infop info_ptr));

/* Set row_pointers, which is an array of pointers to scanlines for use

by png_write_png(). */

extern PNG_EXPORT(void,png_set_rows) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_bytepp row_pointers));

#endif



/* Returns number of color channels in image. */

extern PNG_EXPORT(png_byte,png_get_channels) PNGARG((png_structp png_ptr,

png_infop info_ptr));



#ifdef PNG_EASY_ACCESS_SUPPORTED

/* Returns image width in pixels. */

extern PNG_EXPORT(png_uint_32, png_get_image_width) PNGARG((png_structp

png_ptr, png_infop info_ptr));



/* Returns image height in pixels. */

extern PNG_EXPORT(png_uint_32, png_get_image_height) PNGARG((png_structp

png_ptr, png_infop info_ptr));



/* Returns image bit_depth. */

extern PNG_EXPORT(png_byte, png_get_bit_depth) PNGARG((png_structp

png_ptr, png_infop info_ptr));



/* Returns image color_type. */

extern PNG_EXPORT(png_byte, png_get_color_type) PNGARG((png_structp

png_ptr, png_infop info_ptr));



/* Returns image filter_type. */

extern PNG_EXPORT(png_byte, png_get_filter_type) PNGARG((png_structp

png_ptr, png_infop info_ptr));



/* Returns image interlace_type. */

extern PNG_EXPORT(png_byte, png_get_interlace_type) PNGARG((png_structp

png_ptr, png_infop info_ptr));



/* Returns image compression_type. */

extern PNG_EXPORT(png_byte, png_get_compression_type) PNGARG((png_structp

png_ptr, png_infop info_ptr));



/* Returns image resolution in pixels per meter, from pHYs chunk data. */

extern PNG_EXPORT(png_uint_32, png_get_pixels_per_meter) PNGARG((png_structp

png_ptr, png_infop info_ptr));

extern PNG_EXPORT(png_uint_32, png_get_x_pixels_per_meter) PNGARG((png_structp

png_ptr, png_infop info_ptr));

extern PNG_EXPORT(png_uint_32, png_get_y_pixels_per_meter) PNGARG((png_structp

png_ptr, png_infop info_ptr));



/* Returns pixel aspect ratio, computed from pHYs chunk data.  */

#ifdef PNG_FLOATING_POINT_SUPPORTED

extern PNG_EXPORT(float, png_get_pixel_aspect_ratio) PNGARG((png_structp

png_ptr, png_infop info_ptr));

#endif



/* Returns image x, y offset in pixels or microns, from oFFs chunk data. */

extern PNG_EXPORT(png_int_32, png_get_x_offset_pixels) PNGARG((png_structp

png_ptr, png_infop info_ptr));

extern PNG_EXPORT(png_int_32, png_get_y_offset_pixels) PNGARG((png_structp

png_ptr, png_infop info_ptr));

extern PNG_EXPORT(png_int_32, png_get_x_offset_microns) PNGARG((png_structp

png_ptr, png_infop info_ptr));

extern PNG_EXPORT(png_int_32, png_get_y_offset_microns) PNGARG((png_structp

png_ptr, png_infop info_ptr));



#endif /* PNG_EASY_ACCESS_SUPPORTED */



/* Returns pointer to signature string read from PNG header */

extern PNG_EXPORT(png_bytep,png_get_signature) PNGARG((png_structp png_ptr,

png_infop info_ptr));



#if defined(PNG_bKGD_SUPPORTED)

extern PNG_EXPORT(png_uint_32,png_get_bKGD) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_color_16p *background));

#endif



#if defined(PNG_bKGD_SUPPORTED)

extern PNG_EXPORT(void,png_set_bKGD) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_color_16p background));

#endif



#if defined(PNG_cHRM_SUPPORTED)

#ifdef PNG_FLOATING_POINT_SUPPORTED

extern PNG_EXPORT(png_uint_32,png_get_cHRM) PNGARG((png_structp png_ptr,

   png_infop info_ptr, double *white_x, double *white_y, double *red_x,

   double *red_y, double *green_x, double *green_y, double *blue_x,

   double *blue_y));

#endif

#ifdef PNG_FIXED_POINT_SUPPORTED

extern PNG_EXPORT(png_uint_32,png_get_cHRM_fixed) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_fixed_point *int_white_x, png_fixed_point

   *int_white_y, png_fixed_point *int_red_x, png_fixed_point *int_red_y,

   png_fixed_point *int_green_x, png_fixed_point *int_green_y, png_fixed_point

   *int_blue_x, png_fixed_point *int_blue_y));

#endif

#endif



#if defined(PNG_cHRM_SUPPORTED)

#ifdef PNG_FLOATING_POINT_SUPPORTED

extern PNG_EXPORT(void,png_set_cHRM) PNGARG((png_structp png_ptr,

   png_infop info_ptr, double white_x, double white_y, double red_x,

   double red_y, double green_x, double green_y, double blue_x, double blue_y));

#endif

#ifdef PNG_FIXED_POINT_SUPPORTED

extern PNG_EXPORT(void,png_set_cHRM_fixed) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_fixed_point int_white_x, png_fixed_point int_white_y,

   png_fixed_point int_red_x, png_fixed_point int_red_y, png_fixed_point

   int_green_x, png_fixed_point int_green_y, png_fixed_point int_blue_x,

   png_fixed_point int_blue_y));

#endif

#endif



#if defined(PNG_gAMA_SUPPORTED)

#ifdef PNG_FLOATING_POINT_SUPPORTED

extern PNG_EXPORT(png_uint_32,png_get_gAMA) PNGARG((png_structp png_ptr,

   png_infop info_ptr, double *file_gamma));

#endif

extern PNG_EXPORT(png_uint_32,png_get_gAMA_fixed) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_fixed_point *int_file_gamma));

#endif



#if defined(PNG_gAMA_SUPPORTED)

#ifdef PNG_FLOATING_POINT_SUPPORTED

extern PNG_EXPORT(void,png_set_gAMA) PNGARG((png_structp png_ptr,

   png_infop info_ptr, double file_gamma));

#endif

extern PNG_EXPORT(void,png_set_gAMA_fixed) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_fixed_point int_file_gamma));

#endif



#if defined(PNG_hIST_SUPPORTED)

extern PNG_EXPORT(png_uint_32,png_get_hIST) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_uint_16p *hist));

#endif



#if defined(PNG_hIST_SUPPORTED)

extern PNG_EXPORT(void,png_set_hIST) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_uint_16p hist));

#endif



extern PNG_EXPORT(png_uint_32,png_get_IHDR) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_uint_32 *width, png_uint_32 *height,

   int *bit_depth, int *color_type, int *interlace_method,

   int *compression_method, int *filter_method));



extern PNG_EXPORT(void,png_set_IHDR) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_uint_32 width, png_uint_32 height, int bit_depth,

   int color_type, int interlace_method, int compression_method,

   int filter_method));



#if defined(PNG_oFFs_SUPPORTED)

extern PNG_EXPORT(png_uint_32,png_get_oFFs) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_int_32 *offset_x, png_int_32 *offset_y,

   int *unit_type));

#endif



#if defined(PNG_oFFs_SUPPORTED)

extern PNG_EXPORT(void,png_set_oFFs) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_int_32 offset_x, png_int_32 offset_y,

   int unit_type));

#endif



#if defined(PNG_pCAL_SUPPORTED)

extern PNG_EXPORT(png_uint_32,png_get_pCAL) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_charp *purpose, png_int_32 *X0, png_int_32 *X1,

   int *type, int *nparams, png_charp *units, png_charpp *params));

#endif



#if defined(PNG_pCAL_SUPPORTED)

extern PNG_EXPORT(void,png_set_pCAL) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_charp purpose, png_int_32 X0, png_int_32 X1,

   int type, int nparams, png_charp units, png_charpp params));

#endif



#if defined(PNG_pHYs_SUPPORTED)

extern PNG_EXPORT(png_uint_32,png_get_pHYs) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type));

#endif



#if defined(PNG_pHYs_SUPPORTED)

extern PNG_EXPORT(void,png_set_pHYs) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_uint_32 res_x, png_uint_32 res_y, int unit_type));

#endif



extern PNG_EXPORT(png_uint_32,png_get_PLTE) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_colorp *palette, int *num_palette));



extern PNG_EXPORT(void,png_set_PLTE) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_colorp palette, int num_palette));



#if defined(PNG_sBIT_SUPPORTED)

extern PNG_EXPORT(png_uint_32,png_get_sBIT) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_color_8p *sig_bit));

#endif



#if defined(PNG_sBIT_SUPPORTED)

extern PNG_EXPORT(void,png_set_sBIT) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_color_8p sig_bit));

#endif



#if defined(PNG_sRGB_SUPPORTED)

extern PNG_EXPORT(png_uint_32,png_get_sRGB) PNGARG((png_structp png_ptr,

   png_infop info_ptr, int *intent));

#endif



#if defined(PNG_sRGB_SUPPORTED)

extern PNG_EXPORT(void,png_set_sRGB) PNGARG((png_structp png_ptr,

   png_infop info_ptr, int intent));

extern PNG_EXPORT(void,png_set_sRGB_gAMA_and_cHRM) PNGARG((png_structp png_ptr,

   png_infop info_ptr, int intent));

#endif



#if defined(PNG_iCCP_SUPPORTED)

extern PNG_EXPORT(png_uint_32,png_get_iCCP) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_charpp name, int *compression_type,

   png_charpp profile, png_uint_32 *proflen));

   /* Note to maintainer: profile should be png_bytepp */

#endif



#if defined(PNG_iCCP_SUPPORTED)

extern PNG_EXPORT(void,png_set_iCCP) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_charp name, int compression_type,

   png_charp profile, png_uint_32 proflen));

   /* Note to maintainer: profile should be png_bytep */

#endif



#if defined(PNG_sPLT_SUPPORTED)

extern PNG_EXPORT(png_uint_32,png_get_sPLT) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_sPLT_tpp entries));

#endif



#if defined(PNG_sPLT_SUPPORTED)

extern PNG_EXPORT(void,png_set_sPLT) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_sPLT_tp entries, int nentries));

#endif



#if defined(PNG_TEXT_SUPPORTED)

/* png_get_text also returns the number of text chunks in *num_text */

extern PNG_EXPORT(png_uint_32,png_get_text) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_textp *text_ptr, int *num_text));

#endif



/*

 *  Note while png_set_text() will accept a structure whose text,

 *  language, and  translated keywords are NULL pointers, the structure

 *  returned by png_get_text will always contain regular

 *  zero-terminated C strings.  They might be empty strings but

 *  they will never be NULL pointers.

 */



#if defined(PNG_TEXT_SUPPORTED)

extern PNG_EXPORT(void,png_set_text) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_textp text_ptr, int num_text));

#endif



#if defined(PNG_tIME_SUPPORTED)

extern PNG_EXPORT(png_uint_32,png_get_tIME) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_timep *mod_time));

#endif



#if defined(PNG_tIME_SUPPORTED)

extern PNG_EXPORT(void,png_set_tIME) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_timep mod_time));

#endif



#if defined(PNG_tRNS_SUPPORTED)

extern PNG_EXPORT(png_uint_32,png_get_tRNS) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_bytep *trans, int *num_trans,

   png_color_16p *trans_values));

#endif



#if defined(PNG_tRNS_SUPPORTED)

extern PNG_EXPORT(void,png_set_tRNS) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_bytep trans, int num_trans,

   png_color_16p trans_values));

#endif



#if defined(PNG_tRNS_SUPPORTED)

#endif



#if defined(PNG_sCAL_SUPPORTED)

#ifdef PNG_FLOATING_POINT_SUPPORTED

extern PNG_EXPORT(png_uint_32,png_get_sCAL) PNGARG((png_structp png_ptr,

   png_infop info_ptr, int *unit, double *width, double *height));

#else

#ifdef PNG_FIXED_POINT_SUPPORTED

extern PNG_EXPORT(png_uint_32,png_get_sCAL_s) PNGARG((png_structp png_ptr,

   png_infop info_ptr, int *unit, png_charpp swidth, png_charpp sheight));

#endif

#endif

#endif /* PNG_sCAL_SUPPORTED */



#if defined(PNG_sCAL_SUPPORTED)

#ifdef PNG_FLOATING_POINT_SUPPORTED

extern PNG_EXPORT(void,png_set_sCAL) PNGARG((png_structp png_ptr,

   png_infop info_ptr, int unit, double width, double height));

#endif

#ifdef PNG_FIXED_POINT_SUPPORTED

extern PNG_EXPORT(void,png_set_sCAL_s) PNGARG((png_structp png_ptr,

   png_infop info_ptr, int unit, png_charp swidth, png_charp sheight));

#endif

#endif /* PNG_sCAL_SUPPORTED || PNG_WRITE_sCAL_SUPPORTED */



#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)

/* provide a list of chunks and how they are to be handled, if the built-in

   handling or default unknown chunk handling is not desired.  Any chunks not

   listed will be handled in the default manner.  The IHDR and IEND chunks

   must not be listed.

      keep = 0: follow default behavour

           = 1: do not keep

           = 2: keep only if safe-to-copy

           = 3: keep even if unsafe-to-copy

*/

extern PNG_EXPORT(void, png_set_keep_unknown_chunks) PNGARG((png_structp

   png_ptr, int keep, png_bytep chunk_list, int num_chunks));

extern PNG_EXPORT(void, png_set_unknown_chunks) PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_unknown_chunkp unknowns, int num_unknowns));

extern PNG_EXPORT(void, png_set_unknown_chunk_location)

   PNGARG((png_structp png_ptr, png_infop info_ptr, int chunk, int location));

extern PNG_EXPORT(png_uint_32,png_get_unknown_chunks) PNGARG((png_structp

   png_ptr, png_infop info_ptr, png_unknown_chunkpp entries));

#endif

#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED

PNG_EXPORT(int,png_handle_as_unknown) PNGARG((png_structp png_ptr, png_bytep

   chunk_name));

#endif



/* Png_free_data() will turn off the "valid" flag for anything it frees.

   If you need to turn it off for a chunk that your application has freed,

   you can use png_set_invalid(png_ptr, info_ptr, PNG_INFO_CHNK); */

extern PNG_EXPORT(void, png_set_invalid) PNGARG((png_structp png_ptr,

   png_infop info_ptr, int mask));



#if defined(PNG_INFO_IMAGE_SUPPORTED)

/* The "params" pointer is currently not used and is for future expansion. */

extern PNG_EXPORT(void, png_read_png) PNGARG((png_structp png_ptr,

                        png_infop info_ptr,

                        int transforms,

                        png_voidp params));

extern PNG_EXPORT(void, png_write_png) PNGARG((png_structp png_ptr,

                        png_infop info_ptr,

                        int transforms,

                        png_voidp params));

#endif



/* Define PNG_DEBUG at compile time for debugging information.  Higher

 * numbers for PNG_DEBUG mean more debugging information.  This has

 * only been added since version 0.95 so it is not implemented throughout

 * libpng yet, but more support will be added as needed.

 */

#ifdef PNG_DEBUG

#if (PNG_DEBUG > 0)

#if !defined(PNG_DEBUG_FILE) && defined(_MSC_VER)

#include <crtdbg.h>

#if (PNG_DEBUG > 1)

#define png_debug(l,m)  _RPT0(_CRT_WARN,m)

#define png_debug1(l,m,p1)  _RPT1(_CRT_WARN,m,p1)

#define png_debug2(l,m,p1,p2) _RPT2(_CRT_WARN,m,p1,p2)

#endif

#else /* PNG_DEBUG_FILE || !_MSC_VER */

#ifndef PNG_DEBUG_FILE

#define PNG_DEBUG_FILE stderr

#endif /* PNG_DEBUG_FILE */

#if (PNG_DEBUG > 1)

#define png_debug(l,m) \

{ \

     int num_tabs=l; \

     fprintf(PNG_DEBUG_FILE,"%s"m,(num_tabs==1 ? "\t" : \

       (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":"")))); \

}

#define png_debug1(l,m,p1) \

{ \

     int num_tabs=l; \

     fprintf(PNG_DEBUG_FILE,"%s"m,(num_tabs==1 ? "\t" : \

       (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))),p1); \

}

#define png_debug2(l,m,p1,p2) \

{ \

     int num_tabs=l; \

     fprintf(PNG_DEBUG_FILE,"%s"m,(num_tabs==1 ? "\t" : \

       (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))),p1,p2); \

}

#endif /* (PNG_DEBUG > 1) */

#endif /* _MSC_VER */

#endif /* (PNG_DEBUG > 0) */

#endif /* PNG_DEBUG */

#ifndef png_debug

#define png_debug(l, m)

#endif

#ifndef png_debug1

#define png_debug1(l, m, p1)

#endif

#ifndef png_debug2

#define png_debug2(l, m, p1, p2)

#endif



extern PNG_EXPORT(png_bytep,png_sig_bytes) PNGARG((void));



extern PNG_EXPORT(png_charp,png_get_copyright) PNGARG((png_structp png_ptr));

extern PNG_EXPORT(png_charp,png_get_header_ver) PNGARG((png_structp png_ptr));

extern PNG_EXPORT(png_charp,png_get_header_version) PNGARG((png_structp png_ptr));

extern PNG_EXPORT(png_charp,png_get_libpng_ver) PNGARG((png_structp png_ptr));



#ifdef PNG_MNG_FEATURES_SUPPORTED

extern PNG_EXPORT(png_uint_32,png_permit_mng_features) PNGARG((png_structp

   png_ptr, png_uint_32 mng_features_permitted));

#endif



/* For use in png_set_keep_unknown, added to version 1.2.6 */

#define PNG_HANDLE_CHUNK_AS_DEFAULT   0

#define PNG_HANDLE_CHUNK_NEVER        1

#define PNG_HANDLE_CHUNK_IF_SAFE      2

#define PNG_HANDLE_CHUNK_ALWAYS       3



/* Added to version 1.2.0 */

#if defined(PNG_ASSEMBLER_CODE_SUPPORTED)

#define PNG_ASM_FLAG_MMX_SUPPORT_COMPILED  0x01  /* not user-settable */

#define PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU    0x02  /* not user-settable */

#define PNG_ASM_FLAG_MMX_READ_COMBINE_ROW  0x04

#define PNG_ASM_FLAG_MMX_READ_INTERLACE    0x08

#define PNG_ASM_FLAG_MMX_READ_FILTER_SUB   0x10

#define PNG_ASM_FLAG_MMX_READ_FILTER_UP    0x20

#define PNG_ASM_FLAG_MMX_READ_FILTER_AVG   0x40

#define PNG_ASM_FLAG_MMX_READ_FILTER_PAETH 0x80

#define PNG_ASM_FLAGS_INITIALIZED          0x80000000  /* not user-settable */



#define PNG_MMX_READ_FLAGS ( PNG_ASM_FLAG_MMX_READ_COMBINE_ROW  \

                           | PNG_ASM_FLAG_MMX_READ_INTERLACE    \

                           | PNG_ASM_FLAG_MMX_READ_FILTER_SUB   \

                           | PNG_ASM_FLAG_MMX_READ_FILTER_UP    \

                           | PNG_ASM_FLAG_MMX_READ_FILTER_AVG   \

                           | PNG_ASM_FLAG_MMX_READ_FILTER_PAETH )

#define PNG_MMX_WRITE_FLAGS ( 0 )



#define PNG_MMX_FLAGS ( PNG_ASM_FLAG_MMX_SUPPORT_COMPILED \

                      | PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU   \

                      | PNG_MMX_READ_FLAGS                \

                      | PNG_MMX_WRITE_FLAGS )



#define PNG_SELECT_READ   1

#define PNG_SELECT_WRITE  2



#if !defined(PNG_1_0_X)

/* pngget.c */

extern PNG_EXPORT(png_uint_32,png_get_mmx_flagmask)

   PNGARG((int flag_select, int *compilerID));



/* pngget.c */

extern PNG_EXPORT(png_uint_32,png_get_asm_flagmask)

   PNGARG((int flag_select));



/* pngget.c */

extern PNG_EXPORT(png_uint_32,png_get_asm_flags)

   PNGARG((png_structp png_ptr));



/* pngget.c */

extern PNG_EXPORT(png_byte,png_get_mmx_bitdepth_threshold)

   PNGARG((png_structp png_ptr));



/* pngget.c */

extern PNG_EXPORT(png_uint_32,png_get_mmx_rowbytes_threshold)

   PNGARG((png_structp png_ptr));



/* pngset.c */

extern PNG_EXPORT(void,png_set_asm_flags)

   PNGARG((png_structp png_ptr, png_uint_32 asm_flags));



/* pngset.c */

extern PNG_EXPORT(void,png_set_mmx_thresholds)

   PNGARG((png_structp png_ptr, png_byte mmx_bitdepth_threshold,

   png_uint_32 mmx_rowbytes_threshold));



#endif /* PNG_1_0_X */

#endif /* PNG_ASSEMBLER_CODE_SUPPORTED */



#if !defined(PNG_1_0_X)

/* png.c, pnggccrd.c, or pngvcrd.c */

extern PNG_EXPORT(int,png_mmx_support) PNGARG((void));



/* Strip the prepended error numbers ("#nnn ") from error and warning

 * messages before passing them to the error or warning handler. */

#ifdef PNG_ERROR_NUMBERS_SUPPORTED

extern PNG_EXPORT(void,png_set_strip_error_numbers) PNGARG((png_structp

   png_ptr, png_uint_32 strip_mode));

#endif



#endif /* PNG_1_0_X */



/* Added at libpng-1.2.6 */

#ifdef PNG_SET_USER_LIMITS_SUPPORTED

extern PNG_EXPORT(void,png_set_user_limits) PNGARG((png_structp

   png_ptr, png_uint_32 user_width_max, png_uint_32 user_height_max));

extern PNG_EXPORT(png_uint_32,png_get_user_width_max) PNGARG((png_structp

   png_ptr));

extern PNG_EXPORT(png_uint_32,png_get_user_height_max) PNGARG((png_structp

   png_ptr));

#endif



/* Maintainer: Put new public prototypes here ^, in libpng.3, and project defs */



#ifdef PNG_READ_COMPOSITE_NODIV_SUPPORTED

/* With these routines we avoid an integer divide, which will be slower on

 * most machines.  However, it does take more operations than the corresponding

 * divide method, so it may be slower on a few RISC systems.  There are two

 * shifts (by 8 or 16 bits) and an addition, versus a single integer divide.

 *

 * Note that the rounding factors are NOT supposed to be the same!  128 and

 * 32768 are correct for the NODIV code; 127 and 32767 are correct for the

 * standard method.

 *

 * [Optimized code by Greg Roelofs and Mark Adler...blame us for bugs. :-) ]

 */



 /* fg and bg should be in `gamma 1.0' space; alpha is the opacity          */



#  define png_composite(composite, fg, alpha, bg)                            \

     { png_uint_16 temp = (png_uint_16)((png_uint_16)(fg) * (png_uint_16)(alpha) \

                        +        (png_uint_16)(bg)*(png_uint_16)(255 -       \

                        (png_uint_16)(alpha)) + (png_uint_16)128);           \

       (composite) = (png_byte)((temp + (temp >> 8)) >> 8); }



#  define png_composite_16(composite, fg, alpha, bg)                         \

     { png_uint_32 temp = (png_uint_32)((png_uint_32)(fg) * (png_uint_32)(alpha) \

                        + (png_uint_32)(bg)*(png_uint_32)(65535L -           \

                        (png_uint_32)(alpha)) + (png_uint_32)32768L);        \

       (composite) = (png_uint_16)((temp + (temp >> 16)) >> 16); }



#else  /* standard method using integer division */



#  define png_composite(composite, fg, alpha, bg)                            \

     (composite) = (png_byte)(((png_uint_16)(fg) * (png_uint_16)(alpha) +    \

       (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) +       \

       (png_uint_16)127) / 255)



#  define png_composite_16(composite, fg, alpha, bg)                         \

     (composite) = (png_uint_16)(((png_uint_32)(fg) * (png_uint_32)(alpha) + \

       (png_uint_32)(bg)*(png_uint_32)(65535L - (png_uint_32)(alpha)) +      \

       (png_uint_32)32767) / (png_uint_32)65535L)



#endif /* PNG_READ_COMPOSITE_NODIV_SUPPORTED */



/* These next functions are used internally in the code.  They generally

 * shouldn't be used unless you are writing code to add or replace some

 * functionality in libpng.  More information about most functions can

 * be found in the files where the functions are located.

 */



#if defined(PNG_INTERNAL)



/* Various modes of operation.  Note that after an init, mode is set to

 * zero automatically when the structure is created.

 */

#define PNG_HAVE_IHDR               0x01

#define PNG_HAVE_PLTE               0x02

#define PNG_HAVE_IDAT               0x04

#define PNG_AFTER_IDAT              0x08

#define PNG_HAVE_IEND               0x10

#define PNG_HAVE_gAMA               0x20

#define PNG_HAVE_cHRM               0x40

#define PNG_HAVE_sRGB               0x80

#define PNG_HAVE_CHUNK_HEADER      0x100

#define PNG_WROTE_tIME             0x200

#define PNG_WROTE_INFO_BEFORE_PLTE 0x400

#define PNG_BACKGROUND_IS_GRAY     0x800

#define PNG_HAVE_PNG_SIGNATURE    0x1000



/* flags for the transformations the PNG library does on the image data */

#define PNG_BGR                0x0001

#define PNG_INTERLACE          0x0002

#define PNG_PACK               0x0004

#define PNG_SHIFT              0x0008

#define PNG_SWAP_BYTES         0x0010

#define PNG_INVERT_MONO        0x0020

#define PNG_DITHER             0x0040

#define PNG_BACKGROUND         0x0080

#define PNG_BACKGROUND_EXPAND  0x0100

                          /*   0x0200 unused */

#define PNG_16_TO_8            0x0400

#define PNG_RGBA               0x0800

#define PNG_EXPAND             0x1000

#define PNG_GAMMA              0x2000

#define PNG_GRAY_TO_RGB        0x4000

#define PNG_FILLER             0x8000L

#define PNG_PACKSWAP          0x10000L

#define PNG_SWAP_ALPHA        0x20000L

#define PNG_STRIP_ALPHA       0x40000L

#define PNG_INVERT_ALPHA      0x80000L

#define PNG_USER_TRANSFORM   0x100000L

#define PNG_RGB_TO_GRAY_ERR  0x200000L

#define PNG_RGB_TO_GRAY_WARN 0x400000L

#define PNG_RGB_TO_GRAY      0x600000L  /* two bits, RGB_TO_GRAY_ERR|WARN */

#define PNG_ADD_ALPHA       0x1000000L  /* Added to libpng-1.2.7 */



/* flags for png_create_struct */

#define PNG_STRUCT_PNG   0x0001

#define PNG_STRUCT_INFO  0x0002



/* Scaling factor for filter heuristic weighting calculations */

#define PNG_WEIGHT_SHIFT 8

#define PNG_WEIGHT_FACTOR (1<<(PNG_WEIGHT_SHIFT))

#define PNG_COST_SHIFT 3

#define PNG_COST_FACTOR (1<<(PNG_COST_SHIFT))



/* flags for the png_ptr->flags rather than declaring a byte for each one */

#define PNG_FLAG_ZLIB_CUSTOM_STRATEGY     0x0001

#define PNG_FLAG_ZLIB_CUSTOM_LEVEL        0x0002

#define PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL    0x0004

#define PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS  0x0008

#define PNG_FLAG_ZLIB_CUSTOM_METHOD       0x0010

#define PNG_FLAG_ZLIB_FINISHED            0x0020

#define PNG_FLAG_ROW_INIT                 0x0040

#define PNG_FLAG_FILLER_AFTER             0x0080

#define PNG_FLAG_CRC_ANCILLARY_USE        0x0100

#define PNG_FLAG_CRC_ANCILLARY_NOWARN     0x0200

#define PNG_FLAG_CRC_CRITICAL_USE         0x0400

#define PNG_FLAG_CRC_CRITICAL_IGNORE      0x0800

#define PNG_FLAG_FREE_PLTE                0x1000

#define PNG_FLAG_FREE_TRNS                0x2000

#define PNG_FLAG_FREE_HIST                0x4000

#define PNG_FLAG_KEEP_UNKNOWN_CHUNKS      0x8000L

#define PNG_FLAG_KEEP_UNSAFE_CHUNKS       0x10000L

#define PNG_FLAG_LIBRARY_MISMATCH         0x20000L

#define PNG_FLAG_STRIP_ERROR_NUMBERS      0x40000L

#define PNG_FLAG_STRIP_ERROR_TEXT         0x80000L

#define PNG_FLAG_MALLOC_NULL_MEM_OK       0x100000L



#define PNG_FLAG_CRC_ANCILLARY_MASK (PNG_FLAG_CRC_ANCILLARY_USE | \

                                     PNG_FLAG_CRC_ANCILLARY_NOWARN)



#define PNG_FLAG_CRC_CRITICAL_MASK  (PNG_FLAG_CRC_CRITICAL_USE | \

                                     PNG_FLAG_CRC_CRITICAL_IGNORE)



#define PNG_FLAG_CRC_MASK           (PNG_FLAG_CRC_ANCILLARY_MASK | \

                                     PNG_FLAG_CRC_CRITICAL_MASK)



/* save typing and make code easier to understand */



#define PNG_COLOR_DIST(c1, c2) (abs((int)((c1).red) - (int)((c2).red)) + \

   abs((int)((c1).green) - (int)((c2).green)) + \

   abs((int)((c1).blue) - (int)((c2).blue)))



/* Added to libpng-1.2.6 JB */

#define PNG_ROWBYTES(pixel_bits, width) \

    ((pixel_bits) >= 8 ? \

    ((width) * (((png_uint_32)(pixel_bits)) >> 3)) : \

    (( ((width) * ((png_uint_32)(pixel_bits))) + 7) >> 3) )



/* PNG_OUT_OF_RANGE returns true if value is outside the range

   ideal-delta..ideal+delta.  Each argument is evaluated twice.

   "ideal" and "delta" should be constants, normally simple

   integers, "value" a variable. Added to libpng-1.2.6 JB */

#define PNG_OUT_OF_RANGE(value, ideal, delta) \

        ( (value) < (ideal)-(delta) || (value) > (ideal)+(delta) )



/* variables declared in png.c - only it needs to define PNG_NO_EXTERN */

#if !defined(PNG_NO_EXTERN) || defined(PNG_ALWAYS_EXTERN)

/* place to hold the signature string for a PNG file. */

#ifdef PNG_USE_GLOBAL_ARRAYS

   PNG_EXPORT_VAR (const png_byte FARDATA) png_sig[8];

#else

#define png_sig png_sig_bytes(NULL)

#endif

#endif /* PNG_NO_EXTERN */



/* Constant strings for known chunk types.  If you need to add a chunk,

 * define the name here, and add an invocation of the macro in png.c and

 * wherever it's needed.

 */

#define PNG_IHDR const png_byte png_IHDR[5] = { 73,  72,  68,  82, '\0'}

#define PNG_IDAT const png_byte png_IDAT[5] = { 73,  68,  65,  84, '\0'}

#define PNG_IEND const png_byte png_IEND[5] = { 73,  69,  78,  68, '\0'}

#define PNG_PLTE const png_byte png_PLTE[5] = { 80,  76,  84,  69, '\0'}

#define PNG_bKGD const png_byte png_bKGD[5] = { 98,  75,  71,  68, '\0'}

#define PNG_cHRM const png_byte png_cHRM[5] = { 99,  72,  82,  77, '\0'}

#define PNG_gAMA const png_byte png_gAMA[5] = {103,  65,  77,  65, '\0'}

#define PNG_hIST const png_byte png_hIST[5] = {104,  73,  83,  84, '\0'}

#define PNG_iCCP const png_byte png_iCCP[5] = {105,  67,  67,  80, '\0'}

#define PNG_iTXt const png_byte png_iTXt[5] = {105,  84,  88, 116, '\0'}

#define PNG_oFFs const png_byte png_oFFs[5] = {111,  70,  70, 115, '\0'}

#define PNG_pCAL const png_byte png_pCAL[5] = {112,  67,  65,  76, '\0'}

#define PNG_sCAL const png_byte png_sCAL[5] = {115,  67,  65,  76, '\0'}

#define PNG_pHYs const png_byte png_pHYs[5] = {112,  72,  89, 115, '\0'}

#define PNG_sBIT const png_byte png_sBIT[5] = {115,  66,  73,  84, '\0'}

#define PNG_sPLT const png_byte png_sPLT[5] = {115,  80,  76,  84, '\0'}

#define PNG_sRGB const png_byte png_sRGB[5] = {115,  82,  71,  66, '\0'}

#define PNG_tEXt const png_byte png_tEXt[5] = {116,  69,  88, 116, '\0'}

#define PNG_tIME const png_byte png_tIME[5] = {116,  73,  77,  69, '\0'}

#define PNG_tRNS const png_byte png_tRNS[5] = {116,  82,  78,  83, '\0'}

#define PNG_zTXt const png_byte png_zTXt[5] = {122,  84,  88, 116, '\0'}



#ifdef PNG_USE_GLOBAL_ARRAYS

PNG_EXPORT_VAR (const png_byte FARDATA) png_IHDR[5];

PNG_EXPORT_VAR (const png_byte FARDATA) png_IDAT[5];

PNG_EXPORT_VAR (const png_byte FARDATA) png_IEND[5];

PNG_EXPORT_VAR (const png_byte FARDATA) png_PLTE[5];

PNG_EXPORT_VAR (const png_byte FARDATA) png_bKGD[5];

PNG_EXPORT_VAR (const png_byte FARDATA) png_cHRM[5];

PNG_EXPORT_VAR (const png_byte FARDATA) png_gAMA[5];

PNG_EXPORT_VAR (const png_byte FARDATA) png_hIST[5];

PNG_EXPORT_VAR (const png_byte FARDATA) png_iCCP[5];

PNG_EXPORT_VAR (const png_byte FARDATA) png_iTXt[5];

PNG_EXPORT_VAR (const png_byte FARDATA) png_oFFs[5];

PNG_EXPORT_VAR (const png_byte FARDATA) png_pCAL[5];

PNG_EXPORT_VAR (const png_byte FARDATA) png_sCAL[5];

PNG_EXPORT_VAR (const png_byte FARDATA) png_pHYs[5];

PNG_EXPORT_VAR (const png_byte FARDATA) png_sBIT[5];

PNG_EXPORT_VAR (const png_byte FARDATA) png_sPLT[5];

PNG_EXPORT_VAR (const png_byte FARDATA) png_sRGB[5];

PNG_EXPORT_VAR (const png_byte FARDATA) png_tEXt[5];

PNG_EXPORT_VAR (const png_byte FARDATA) png_tIME[5];

PNG_EXPORT_VAR (const png_byte FARDATA) png_tRNS[5];

PNG_EXPORT_VAR (const png_byte FARDATA) png_zTXt[5];

#endif /* PNG_USE_GLOBAL_ARRAYS */





/* Inline macros to do direct reads of bytes from the input buffer.  These

 * require that you are using an architecture that uses PNG byte ordering

 * (MSB first) and supports unaligned data storage.  I think that PowerPC

 * in big-endian mode and 680x0 are the only ones that will support this.

 * The x86 line of processors definitely do not.  The png_get_int_32()

 * routine also assumes we are using two's complement format for negative

 * values, which is almost certainly true.

 */

#if defined(PNG_READ_BIG_ENDIAN_SUPPORTED)

#  if defined(PNG_pCAL_SUPPORTED) || defined(PNG_oFFs_SUPPORTED)

#    define png_get_int_32(buf) ( *((png_int_32p) (buf)))

#  endif

#  define png_get_uint_32(buf) ( *((png_uint_32p) (buf)))

#  define png_get_uint_16(buf) ( *((png_uint_16p) (buf)))

#else

#  if defined(PNG_pCAL_SUPPORTED) || defined(PNG_oFFs_SUPPORTED)

PNG_EXTERN png_int_32 png_get_int_32 PNGARG((png_bytep buf));

#  endif

PNG_EXTERN png_uint_32 png_get_uint_32 PNGARG((png_bytep buf));

PNG_EXTERN png_uint_16 png_get_uint_16 PNGARG((png_bytep buf));

#endif /* !PNG_READ_BIG_ENDIAN_SUPPORTED */

PNG_EXTERN png_uint_32 png_get_uint_31 PNGARG((png_structp png_ptr,

  png_bytep buf));



/* Initialize png_ptr struct for reading, and allocate any other memory.

 * (old interface - DEPRECATED - use png_create_read_struct instead).

 */

extern PNG_EXPORT(void,png_read_init) PNGARG((png_structp png_ptr));

#undef png_read_init

#define png_read_init(png_ptr) png_read_init_3(&png_ptr, \

    PNG_LIBPNG_VER_STRING,  png_sizeof(png_struct));

extern PNG_EXPORT(void,png_read_init_3) PNGARG((png_structpp ptr_ptr,

    png_const_charp user_png_ver, png_size_t png_struct_size));

extern PNG_EXPORT(void,png_read_init_2) PNGARG((png_structp png_ptr,

    png_const_charp user_png_ver, png_size_t png_struct_size, png_size_t

    png_info_size));



/* Initialize png_ptr struct for writing, and allocate any other memory.

 * (old interface - DEPRECATED - use png_create_write_struct instead).

 */

extern PNG_EXPORT(void,png_write_init) PNGARG((png_structp png_ptr));

#undef png_write_init

#define png_write_init(png_ptr) png_write_init_3(&png_ptr, \

    PNG_LIBPNG_VER_STRING, png_sizeof(png_struct));

extern PNG_EXPORT(void,png_write_init_3) PNGARG((png_structpp ptr_ptr,

    png_const_charp user_png_ver, png_size_t png_struct_size));

extern PNG_EXPORT(void,png_write_init_2) PNGARG((png_structp png_ptr,

    png_const_charp user_png_ver, png_size_t png_struct_size, png_size_t

    png_info_size));



/* Allocate memory for an internal libpng struct */

PNG_EXTERN png_voidp png_create_struct PNGARG((int type));



/* Free memory from internal libpng struct */

PNG_EXTERN void png_destroy_struct PNGARG((png_voidp struct_ptr));



PNG_EXTERN png_voidp png_create_struct_2 PNGARG((int type, png_malloc_ptr

  malloc_fn, png_voidp mem_ptr));

PNG_EXTERN void png_destroy_struct_2 PNGARG((png_voidp struct_ptr,

   png_free_ptr free_fn, png_voidp mem_ptr));



/* Free any memory that info_ptr points to and reset struct. */

PNG_EXTERN void png_info_destroy PNGARG((png_structp png_ptr,

   png_infop info_ptr));



#ifndef PNG_1_0_X

/* Function to allocate memory for zlib. */

PNG_EXTERN voidpf png_zalloc PNGARG((voidpf png_ptr, uInt items, uInt size));



/* Function to free memory for zlib */

PNG_EXTERN void png_zfree PNGARG((voidpf png_ptr, voidpf ptr));



#ifdef PNG_SIZE_T

/* Function to convert a sizeof an item to png_sizeof item */

   PNG_EXTERN png_size_t PNGAPI png_convert_size PNGARG((size_t size));

#endif



/* Next four functions are used internally as callbacks.  PNGAPI is required

 * but not PNG_EXPORT.  PNGAPI added at libpng version 1.2.3. */



PNG_EXTERN void PNGAPI png_default_read_data PNGARG((png_structp png_ptr,

   png_bytep data, png_size_t length));



#ifdef PNG_PROGRESSIVE_READ_SUPPORTED

PNG_EXTERN void PNGAPI png_push_fill_buffer PNGARG((png_structp png_ptr,

   png_bytep buffer, png_size_t length));

#endif



PNG_EXTERN void PNGAPI png_default_write_data PNGARG((png_structp png_ptr,

   png_bytep data, png_size_t length));



#if defined(PNG_WRITE_FLUSH_SUPPORTED)

#if !defined(PNG_NO_STDIO)

PNG_EXTERN void PNGAPI png_default_flush PNGARG((png_structp png_ptr));

#endif

#endif

#else /* PNG_1_0_X */

#ifdef PNG_PROGRESSIVE_READ_SUPPORTED

PNG_EXTERN void png_push_fill_buffer PNGARG((png_structp png_ptr,

   png_bytep buffer, png_size_t length));

#endif

#endif /* PNG_1_0_X */



/* Reset the CRC variable */

PNG_EXTERN void png_reset_crc PNGARG((png_structp png_ptr));



/* Write the "data" buffer to whatever output you are using. */

PNG_EXTERN void png_write_data PNGARG((png_structp png_ptr, png_bytep data,

   png_size_t length));



/* Read data from whatever input you are using into the "data" buffer */

PNG_EXTERN void png_read_data PNGARG((png_structp png_ptr, png_bytep data,

   png_size_t length));



/* Read bytes into buf, and update png_ptr->crc */

PNG_EXTERN void png_crc_read PNGARG((png_structp png_ptr, png_bytep buf,

   png_size_t length));



/* Decompress data in a chunk that uses compression */

#if defined(PNG_zTXt_SUPPORTED) || defined(PNG_iTXt_SUPPORTED) || \

    defined(PNG_iCCP_SUPPORTED) || defined(PNG_sPLT_SUPPORTED)

PNG_EXTERN png_charp png_decompress_chunk PNGARG((png_structp png_ptr,

   int comp_type, png_charp chunkdata, png_size_t chunklength,

   png_size_t prefix_length, png_size_t *data_length));

#endif



/* Read "skip" bytes, read the file crc, and (optionally) verify png_ptr->crc */

PNG_EXTERN int png_crc_finish PNGARG((png_structp png_ptr, png_uint_32 skip));



/* Read the CRC from the file and compare it to the libpng calculated CRC */

PNG_EXTERN int png_crc_error PNGARG((png_structp png_ptr));



/* Calculate the CRC over a section of data.  Note that we are only

 * passing a maximum of 64K on systems that have this as a memory limit,

 * since this is the maximum buffer size we can specify.

 */

PNG_EXTERN void png_calculate_crc PNGARG((png_structp png_ptr, png_bytep ptr,

   png_size_t length));



#if defined(PNG_WRITE_FLUSH_SUPPORTED)

PNG_EXTERN void png_flush PNGARG((png_structp png_ptr));

#endif





/* Place a 32-bit number into a buffer in PNG byte order (big-endian).

 * The only currently known PNG chunks that use signed numbers are

 * the ancillary extension chunks, oFFs and pCAL.

 */

PNG_EXTERN void png_save_uint_32 PNGARG((png_bytep buf, png_uint_32 i));



#if defined(PNG_WRITE_pCAL_SUPPORTED) || defined(PNG_WRITE_oFFs_SUPPORTED)

PNG_EXTERN void png_save_int_32 PNGARG((png_bytep buf, png_int_32 i));

#endif



/* Place a 16-bit number into a buffer in PNG byte order.

 * The parameter is declared unsigned int, not png_uint_16,

 * just to avoid potential problems on pre-ANSI C compilers.

 */

PNG_EXTERN void png_save_uint_16 PNGARG((png_bytep buf, unsigned int i));



/* simple function to write the signature */

PNG_EXTERN void png_write_sig PNGARG((png_structp png_ptr));



/* write various chunks */



/* Write the IHDR chunk, and update the png_struct with the necessary

 * information.

 */

PNG_EXTERN void png_write_IHDR PNGARG((png_structp png_ptr, png_uint_32 width,

   png_uint_32 height,

   int bit_depth, int color_type, int compression_method, int filter_method,

   int interlace_method));



PNG_EXTERN void png_write_PLTE PNGARG((png_structp png_ptr, png_colorp palette,

   png_uint_32 num_pal));



PNG_EXTERN void png_write_IDAT PNGARG((png_structp png_ptr, png_bytep data,

   png_size_t length));



PNG_EXTERN void png_write_IEND PNGARG((png_structp png_ptr));



#if defined(PNG_WRITE_gAMA_SUPPORTED)

#ifdef PNG_FLOATING_POINT_SUPPORTED

PNG_EXTERN void png_write_gAMA PNGARG((png_structp png_ptr, double file_gamma));

#endif

#ifdef PNG_FIXED_POINT_SUPPORTED

PNG_EXTERN void png_write_gAMA_fixed PNGARG((png_structp png_ptr, png_fixed_point

    file_gamma));

#endif

#endif



#if defined(PNG_WRITE_sBIT_SUPPORTED)

PNG_EXTERN void png_write_sBIT PNGARG((png_structp png_ptr, png_color_8p sbit,

   int color_type));

#endif



#if defined(PNG_WRITE_cHRM_SUPPORTED)

#ifdef PNG_FLOATING_POINT_SUPPORTED

PNG_EXTERN void png_write_cHRM PNGARG((png_structp png_ptr,

   double white_x, double white_y,

   double red_x, double red_y, double green_x, double green_y,

   double blue_x, double blue_y));

#endif

#ifdef PNG_FIXED_POINT_SUPPORTED

PNG_EXTERN void png_write_cHRM_fixed PNGARG((png_structp png_ptr,

   png_fixed_point int_white_x, png_fixed_point int_white_y,

   png_fixed_point int_red_x, png_fixed_point int_red_y, png_fixed_point

   int_green_x, png_fixed_point int_green_y, png_fixed_point int_blue_x,

   png_fixed_point int_blue_y));

#endif

#endif



#if defined(PNG_WRITE_sRGB_SUPPORTED)

PNG_EXTERN void png_write_sRGB PNGARG((png_structp png_ptr,

   int intent));

#endif



#if defined(PNG_WRITE_iCCP_SUPPORTED)

PNG_EXTERN void png_write_iCCP PNGARG((png_structp png_ptr,

   png_charp name, int compression_type,

   png_charp profile, int proflen));

   /* Note to maintainer: profile should be png_bytep */

#endif



#if defined(PNG_WRITE_sPLT_SUPPORTED)

PNG_EXTERN void png_write_sPLT PNGARG((png_structp png_ptr,

   png_sPLT_tp palette));

#endif



#if defined(PNG_WRITE_tRNS_SUPPORTED)

PNG_EXTERN void png_write_tRNS PNGARG((png_structp png_ptr, png_bytep trans,

   png_color_16p values, int number, int color_type));

#endif



#if defined(PNG_WRITE_bKGD_SUPPORTED)

PNG_EXTERN void png_write_bKGD PNGARG((png_structp png_ptr,

   png_color_16p values, int color_type));

#endif



#if defined(PNG_WRITE_hIST_SUPPORTED)

PNG_EXTERN void png_write_hIST PNGARG((png_structp png_ptr, png_uint_16p hist,

   int num_hist));

#endif



#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \

    defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)

PNG_EXTERN png_size_t png_check_keyword PNGARG((png_structp png_ptr,

   png_charp key, png_charpp new_key));

#endif



#if defined(PNG_WRITE_tEXt_SUPPORTED)

PNG_EXTERN void png_write_tEXt PNGARG((png_structp png_ptr, png_charp key,

   png_charp text, png_size_t text_len));

#endif



#if defined(PNG_WRITE_zTXt_SUPPORTED)

PNG_EXTERN void png_write_zTXt PNGARG((png_structp png_ptr, png_charp key,

   png_charp text, png_size_t text_len, int compression));

#endif



#if defined(PNG_WRITE_iTXt_SUPPORTED)

PNG_EXTERN void png_write_iTXt PNGARG((png_structp png_ptr,

   int compression, png_charp key, png_charp lang, png_charp lang_key,

   png_charp text));

#endif



#if defined(PNG_TEXT_SUPPORTED)  /* Added at version 1.0.14 and 1.2.4 */

PNG_EXTERN int png_set_text_2 PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_textp text_ptr, int num_text));

#endif



#if defined(PNG_WRITE_oFFs_SUPPORTED)

PNG_EXTERN void png_write_oFFs PNGARG((png_structp png_ptr,

   png_int_32 x_offset, png_int_32 y_offset, int unit_type));

#endif



#if defined(PNG_WRITE_pCAL_SUPPORTED)

PNG_EXTERN void png_write_pCAL PNGARG((png_structp png_ptr, png_charp purpose,

   png_int_32 X0, png_int_32 X1, int type, int nparams,

   png_charp units, png_charpp params));

#endif



#if defined(PNG_WRITE_pHYs_SUPPORTED)

PNG_EXTERN void png_write_pHYs PNGARG((png_structp png_ptr,

   png_uint_32 x_pixels_per_unit, png_uint_32 y_pixels_per_unit,

   int unit_type));

#endif



#if defined(PNG_WRITE_tIME_SUPPORTED)

PNG_EXTERN void png_write_tIME PNGARG((png_structp png_ptr,

   png_timep mod_time));

#endif



#if defined(PNG_WRITE_sCAL_SUPPORTED)

#if defined(PNG_FLOATING_POINT_SUPPORTED) && !defined(PNG_NO_STDIO)

PNG_EXTERN void png_write_sCAL PNGARG((png_structp png_ptr,

   int unit, double width, double height));

#else

#ifdef PNG_FIXED_POINT_SUPPORTED

PNG_EXTERN void png_write_sCAL_s PNGARG((png_structp png_ptr,

   int unit, png_charp width, png_charp height));

#endif

#endif

#endif



/* Called when finished processing a row of data */

PNG_EXTERN void png_write_finish_row PNGARG((png_structp png_ptr));



/* Internal use only.   Called before first row of data */

PNG_EXTERN void png_write_start_row PNGARG((png_structp png_ptr));



#if defined(PNG_READ_GAMMA_SUPPORTED)

PNG_EXTERN void png_build_gamma_table PNGARG((png_structp png_ptr));

#endif



/* combine a row of data, dealing with alpha, etc. if requested */

PNG_EXTERN void png_combine_row PNGARG((png_structp png_ptr, png_bytep row,

   int mask));



#if defined(PNG_READ_INTERLACING_SUPPORTED)

/* expand an interlaced row */

/* OLD pre-1.0.9 interface:

PNG_EXTERN void png_do_read_interlace PNGARG((png_row_infop row_info,

   png_bytep row, int pass, png_uint_32 transformations));

 */

PNG_EXTERN void png_do_read_interlace PNGARG((png_structp png_ptr));

#endif



/* GRR TO DO (2.0 or whenever):  simplify other internal calling interfaces */



#if defined(PNG_WRITE_INTERLACING_SUPPORTED)

/* grab pixels out of a row for an interlaced pass */

PNG_EXTERN void png_do_write_interlace PNGARG((png_row_infop row_info,

   png_bytep row, int pass));

#endif



/* unfilter a row */

PNG_EXTERN void png_read_filter_row PNGARG((png_structp png_ptr,

   png_row_infop row_info, png_bytep row, png_bytep prev_row, int filter));



/* Choose the best filter to use and filter the row data */

PNG_EXTERN void png_write_find_filter PNGARG((png_structp png_ptr,

   png_row_infop row_info));



/* Write out the filtered row. */

PNG_EXTERN void png_write_filtered_row PNGARG((png_structp png_ptr,

   png_bytep filtered_row));

/* finish a row while reading, dealing with interlacing passes, etc. */

PNG_EXTERN void png_read_finish_row PNGARG((png_structp png_ptr));



/* initialize the row buffers, etc. */

PNG_EXTERN void png_read_start_row PNGARG((png_structp png_ptr));

/* optional call to update the users info structure */

PNG_EXTERN void png_read_transform_info PNGARG((png_structp png_ptr,

   png_infop info_ptr));



/* these are the functions that do the transformations */

#if defined(PNG_READ_FILLER_SUPPORTED)

PNG_EXTERN void png_do_read_filler PNGARG((png_row_infop row_info,

   png_bytep row, png_uint_32 filler, png_uint_32 flags));

#endif



#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED)

PNG_EXTERN void png_do_read_swap_alpha PNGARG((png_row_infop row_info,

   png_bytep row));

#endif



#if defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)

PNG_EXTERN void png_do_write_swap_alpha PNGARG((png_row_infop row_info,

   png_bytep row));

#endif



#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED)

PNG_EXTERN void png_do_read_invert_alpha PNGARG((png_row_infop row_info,

   png_bytep row));

#endif



#if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)

PNG_EXTERN void png_do_write_invert_alpha PNGARG((png_row_infop row_info,

   png_bytep row));

#endif



#if defined(PNG_WRITE_FILLER_SUPPORTED) || \

    defined(PNG_READ_STRIP_ALPHA_SUPPORTED)

PNG_EXTERN void png_do_strip_filler PNGARG((png_row_infop row_info,

   png_bytep row, png_uint_32 flags));

#endif



#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)

PNG_EXTERN void png_do_swap PNGARG((png_row_infop row_info, png_bytep row));

#endif



#if defined(PNG_READ_PACKSWAP_SUPPORTED) || defined(PNG_WRITE_PACKSWAP_SUPPORTED)

PNG_EXTERN void png_do_packswap PNGARG((png_row_infop row_info, png_bytep row));

#endif



#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)

PNG_EXTERN int png_do_rgb_to_gray PNGARG((png_structp png_ptr, png_row_infop

   row_info, png_bytep row));

#endif



#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)

PNG_EXTERN void png_do_gray_to_rgb PNGARG((png_row_infop row_info,

   png_bytep row));

#endif



#if defined(PNG_READ_PACK_SUPPORTED)

PNG_EXTERN void png_do_unpack PNGARG((png_row_infop row_info, png_bytep row));

#endif



#if defined(PNG_READ_SHIFT_SUPPORTED)

PNG_EXTERN void png_do_unshift PNGARG((png_row_infop row_info, png_bytep row,

   png_color_8p sig_bits));

#endif



#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)

PNG_EXTERN void png_do_invert PNGARG((png_row_infop row_info, png_bytep row));

#endif



#if defined(PNG_READ_16_TO_8_SUPPORTED)

PNG_EXTERN void png_do_chop PNGARG((png_row_infop row_info, png_bytep row));

#endif



#if defined(PNG_READ_DITHER_SUPPORTED)

PNG_EXTERN void png_do_dither PNGARG((png_row_infop row_info,

   png_bytep row, png_bytep palette_lookup, png_bytep dither_lookup));



#  if defined(PNG_CORRECT_PALETTE_SUPPORTED)

PNG_EXTERN void png_correct_palette PNGARG((png_structp png_ptr,

   png_colorp palette, int num_palette));

#  endif

#endif



#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)

PNG_EXTERN void png_do_bgr PNGARG((png_row_infop row_info, png_bytep row));

#endif



#if defined(PNG_WRITE_PACK_SUPPORTED)

PNG_EXTERN void png_do_pack PNGARG((png_row_infop row_info,

   png_bytep row, png_uint_32 bit_depth));

#endif



#if defined(PNG_WRITE_SHIFT_SUPPORTED)

PNG_EXTERN void png_do_shift PNGARG((png_row_infop row_info, png_bytep row,

   png_color_8p bit_depth));

#endif



#if defined(PNG_READ_BACKGROUND_SUPPORTED)

#if defined(PNG_READ_GAMMA_SUPPORTED)

PNG_EXTERN void png_do_background PNGARG((png_row_infop row_info, png_bytep row,

   png_color_16p trans_values, png_color_16p background,

   png_color_16p background_1,

   png_bytep gamma_table, png_bytep gamma_from_1, png_bytep gamma_to_1,

   png_uint_16pp gamma_16, png_uint_16pp gamma_16_from_1,

   png_uint_16pp gamma_16_to_1, int gamma_shift));

#else

PNG_EXTERN void png_do_background PNGARG((png_row_infop row_info, png_bytep row,

   png_color_16p trans_values, png_color_16p background));

#endif

#endif



#if defined(PNG_READ_GAMMA_SUPPORTED)

PNG_EXTERN void png_do_gamma PNGARG((png_row_infop row_info, png_bytep row,

   png_bytep gamma_table, png_uint_16pp gamma_16_table,

   int gamma_shift));

#endif



#if defined(PNG_READ_EXPAND_SUPPORTED)

PNG_EXTERN void png_do_expand_palette PNGARG((png_row_infop row_info,

   png_bytep row, png_colorp palette, png_bytep trans, int num_trans));

PNG_EXTERN void png_do_expand PNGARG((png_row_infop row_info,

   png_bytep row, png_color_16p trans_value));

#endif



/* The following decodes the appropriate chunks, and does error correction,

 * then calls the appropriate callback for the chunk if it is valid.

 */



/* decode the IHDR chunk */

PNG_EXTERN void png_handle_IHDR PNGARG((png_structp png_ptr, png_infop info_ptr,

   png_uint_32 length));

PNG_EXTERN void png_handle_PLTE PNGARG((png_structp png_ptr, png_infop info_ptr,

   png_uint_32 length));

PNG_EXTERN void png_handle_IEND PNGARG((png_structp png_ptr, png_infop info_ptr,

   png_uint_32 length));



#if defined(PNG_READ_bKGD_SUPPORTED)

PNG_EXTERN void png_handle_bKGD PNGARG((png_structp png_ptr, png_infop info_ptr,

   png_uint_32 length));

#endif



#if defined(PNG_READ_cHRM_SUPPORTED)

PNG_EXTERN void png_handle_cHRM PNGARG((png_structp png_ptr, png_infop info_ptr,

   png_uint_32 length));

#endif



#if defined(PNG_READ_gAMA_SUPPORTED)

PNG_EXTERN void png_handle_gAMA PNGARG((png_structp png_ptr, png_infop info_ptr,

   png_uint_32 length));

#endif



#if defined(PNG_READ_hIST_SUPPORTED)

PNG_EXTERN void png_handle_hIST PNGARG((png_structp png_ptr, png_infop info_ptr,

   png_uint_32 length));

#endif



#if defined(PNG_READ_iCCP_SUPPORTED)

extern void png_handle_iCCP PNGARG((png_structp png_ptr, png_infop info_ptr,

   png_uint_32 length));

#endif /* PNG_READ_iCCP_SUPPORTED */



#if defined(PNG_READ_iTXt_SUPPORTED)

PNG_EXTERN void png_handle_iTXt PNGARG((png_structp png_ptr, png_infop info_ptr,

   png_uint_32 length));

#endif



#if defined(PNG_READ_oFFs_SUPPORTED)

PNG_EXTERN void png_handle_oFFs PNGARG((png_structp png_ptr, png_infop info_ptr,

   png_uint_32 length));

#endif



#if defined(PNG_READ_pCAL_SUPPORTED)

PNG_EXTERN void png_handle_pCAL PNGARG((png_structp png_ptr, png_infop info_ptr,

   png_uint_32 length));

#endif



#if defined(PNG_READ_pHYs_SUPPORTED)

PNG_EXTERN void png_handle_pHYs PNGARG((png_structp png_ptr, png_infop info_ptr,

   png_uint_32 length));

#endif



#if defined(PNG_READ_sBIT_SUPPORTED)

PNG_EXTERN void png_handle_sBIT PNGARG((png_structp png_ptr, png_infop info_ptr,

   png_uint_32 length));

#endif



#if defined(PNG_READ_sCAL_SUPPORTED)

PNG_EXTERN void png_handle_sCAL PNGARG((png_structp png_ptr, png_infop info_ptr,

   png_uint_32 length));

#endif



#if defined(PNG_READ_sPLT_SUPPORTED)

extern void png_handle_sPLT PNGARG((png_structp png_ptr, png_infop info_ptr,

   png_uint_32 length));

#endif /* PNG_READ_sPLT_SUPPORTED */



#if defined(PNG_READ_sRGB_SUPPORTED)

PNG_EXTERN void png_handle_sRGB PNGARG((png_structp png_ptr, png_infop info_ptr,

   png_uint_32 length));

#endif



#if defined(PNG_READ_tEXt_SUPPORTED)

PNG_EXTERN void png_handle_tEXt PNGARG((png_structp png_ptr, png_infop info_ptr,

   png_uint_32 length));

#endif



#if defined(PNG_READ_tIME_SUPPORTED)

PNG_EXTERN void png_handle_tIME PNGARG((png_structp png_ptr, png_infop info_ptr,

   png_uint_32 length));

#endif



#if defined(PNG_READ_tRNS_SUPPORTED)

PNG_EXTERN void png_handle_tRNS PNGARG((png_structp png_ptr, png_infop info_ptr,

   png_uint_32 length));

#endif



#if defined(PNG_READ_zTXt_SUPPORTED)

PNG_EXTERN void png_handle_zTXt PNGARG((png_structp png_ptr, png_infop info_ptr,

   png_uint_32 length));

#endif



PNG_EXTERN void png_handle_unknown PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_uint_32 length));



PNG_EXTERN void png_check_chunk_name PNGARG((png_structp png_ptr,

   png_bytep chunk_name));



/* handle the transformations for reading and writing */

PNG_EXTERN void png_do_read_transformations PNGARG((png_structp png_ptr));

PNG_EXTERN void png_do_write_transformations PNGARG((png_structp png_ptr));



PNG_EXTERN void png_init_read_transformations PNGARG((png_structp png_ptr));



#ifdef PNG_PROGRESSIVE_READ_SUPPORTED

PNG_EXTERN void png_push_read_chunk PNGARG((png_structp png_ptr,

   png_infop info_ptr));

PNG_EXTERN void png_push_read_sig PNGARG((png_structp png_ptr,

   png_infop info_ptr));

PNG_EXTERN void png_push_check_crc PNGARG((png_structp png_ptr));

PNG_EXTERN void png_push_crc_skip PNGARG((png_structp png_ptr,

   png_uint_32 length));

PNG_EXTERN void png_push_crc_finish PNGARG((png_structp png_ptr));

PNG_EXTERN void png_push_save_buffer PNGARG((png_structp png_ptr));

PNG_EXTERN void png_push_restore_buffer PNGARG((png_structp png_ptr,

   png_bytep buffer, png_size_t buffer_length));

PNG_EXTERN void png_push_read_IDAT PNGARG((png_structp png_ptr));

PNG_EXTERN void png_process_IDAT_data PNGARG((png_structp png_ptr,

   png_bytep buffer, png_size_t buffer_length));

PNG_EXTERN void png_push_process_row PNGARG((png_structp png_ptr));

PNG_EXTERN void png_push_handle_unknown PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_uint_32 length));

PNG_EXTERN void png_push_have_info PNGARG((png_structp png_ptr,

   png_infop info_ptr));

PNG_EXTERN void png_push_have_end PNGARG((png_structp png_ptr,

   png_infop info_ptr));

PNG_EXTERN void png_push_have_row PNGARG((png_structp png_ptr, png_bytep row));

PNG_EXTERN void png_push_read_end PNGARG((png_structp png_ptr,

   png_infop info_ptr));

PNG_EXTERN void png_process_some_data PNGARG((png_structp png_ptr,

   png_infop info_ptr));

PNG_EXTERN void png_read_push_finish_row PNGARG((png_structp png_ptr));

#if defined(PNG_READ_tEXt_SUPPORTED)

PNG_EXTERN void png_push_handle_tEXt PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_uint_32 length));

PNG_EXTERN void png_push_read_tEXt PNGARG((png_structp png_ptr,

   png_infop info_ptr));

#endif

#if defined(PNG_READ_zTXt_SUPPORTED)

PNG_EXTERN void png_push_handle_zTXt PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_uint_32 length));

PNG_EXTERN void png_push_read_zTXt PNGARG((png_structp png_ptr,

   png_infop info_ptr));

#endif

#if defined(PNG_READ_iTXt_SUPPORTED)

PNG_EXTERN void png_push_handle_iTXt PNGARG((png_structp png_ptr,

   png_infop info_ptr, png_uint_32 length));

PNG_EXTERN void png_push_read_iTXt PNGARG((png_structp png_ptr,

   png_infop info_ptr));

#endif



#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */



#ifdef PNG_MNG_FEATURES_SUPPORTED

PNG_EXTERN void png_do_read_intrapixel PNGARG((png_row_infop row_info,

   png_bytep row));

PNG_EXTERN void png_do_write_intrapixel PNGARG((png_row_infop row_info,

   png_bytep row));

#endif



#if defined(PNG_ASSEMBLER_CODE_SUPPORTED)

/* png.c */ /* PRIVATE */

PNG_EXTERN void png_init_mmx_flags PNGARG((png_structp png_ptr));

#endif

/* Maintainer: Put new private prototypes here ^ and in libpngpf.3 */



#endif /* PNG_INTERNAL */



#ifdef __cplusplus

}

#endif



#endif /* PNG_VERSION_INFO_ONLY */

/* do not put anything past this line */

#endif /* PNG_H */