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png.h：源码内容

/*
* ===========================================================================
* PRODUCTION $Log: png.h,v $
* PRODUCTION Revision 1000.1 2004/04/12 17:33:05 gouriano
* PRODUCTION PRODUCTION: UPGRADED [CATCHUP_003] Dev-tree R1.4
* PRODUCTION
* ===========================================================================
*/
/* png.h - header file for PNG reference library
*
* libpng version 1.2.5rc3 - September 18, 2002
*
* 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 1.2.5rc3 - September 18, 2002: 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
* 1.2.5rc1-3 13 10205 12.so.0.1.2.5rc1-3
* 1.0.15rc1-3 10 10015 10.so.0.1.0.15rc1-3
*
* 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 RFC 2083 <ftp://ftp.uu.net/graphics/png/documents/>
* and as a W3C Recommendation <http://www.w3.org/TR/REC.png.html>
*/
/*
* COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:
*
* If you modify libpng you may insert additional notices immediately following
* this sentence.
*
* libpng versions 1.0.7, July 1, 2000, through 1.2.5rc3, September 18, 2002, 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
* 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
* 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
*
* 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 18, 2002
*
* 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 1.2.5rc3 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 "1.2.5rc3"
#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 5
/* This should match the numeric part of the final component of
* PNG_LIBPNG_VER_STRING, omitting any leading zero: */
#define PNG_LIBPNG_VER_BUILD 3
#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 3
/* 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 10205 /* 1.2.5 */
#ifndef PNG_VERSION_INFO_ONLY
/* include the compression library's header */
#include "../cn3d/zlib.h"
/* include all user configurable info, including optional assembler routines */
#include "../cn3d/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_MAX_UINT ((png_uint_32)0x7fffffffL)
/* 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
};
/* This prevents a compiler error in png.c if png.c and png.h are both at
version 1.2.5rc3
*/
typedef png_structp version_1_2_5rc3;
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));
extern PNG_EXPORT(png_uint_32,png_get_compression_buffer_size)
PNGARG((png_structp png_ptr));
extern PNG_EXPORT(void,png_set_compression_buffer_size)
PNGARG((png_structp png_ptr, png_uint_32 size));
/* 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, 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));
/* read the information before the actual image data. */
extern PNG_EXPORT(void,png_read_info) PNGARG((png_structp png_ptr,
png_infop info_ptr));
#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 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
#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));
/* 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));
/* read a row of data. */
extern PNG_EXPORT(void,png_read_row) PNGARG((png_structp png_ptr,
png_bytep row,
png_bytep display_row));
/* read the whole image into memory at once. */
extern PNG_EXPORT(void,png_read_image) PNGARG((png_structp png_ptr,
png_bytepp image));
/* 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));
/* read the end of the PNG file. */
extern PNG_EXPORT(void,png_read_end) PNGARG((png_structp png_ptr,
png_infop info_ptr));
/* 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.
*/