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/* png.h - header file for PNG reference library
* libpng version 1.4.22, September 28, 2017
* Copyright (c) 1998-2002,2004,2006-2017 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.)
* This code is released under the libpng license (See LICENSE, below)
* 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 1.4.22, September 28, 2017: Glenn
* See also "Contributing Authors", below.
* If you modify libpng you may insert additional notices immediately following
* this sentence.
* This code is released under the libpng license.
* libpng versions 1.0.7, July 1, 2000, through 1.4.22, September 28, 2017, are
* Copyright (c) 2000-2002, 2004, 2006-2017 Glenn Randers-Pehrson, are
* derived from libpng-1.0.6, 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
* Cosmin Truta
* 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) 1998-2000 Glenn Randers-Pehrson, are derived from
* libpng-0.96, 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, are derived from libpng-0.88,
* and 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
* 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 Open Source is
* a certification mark of the Open Source Initiative. OSI has not addressed
* the additional disclaimers inserted at version 1.0.7.
* 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.
/* 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 (incompatible with 1.0.0)
* 1.0.7beta11-14 DLLNUM 10007 (binary compatible)
* 1.0.7beta15-18 1 10007 (binary compatible)
* 1.0.7rc1-2 1 10007 (binary compatible)
* 1.0.7 1 10007 (still compatible)
* ...
* 1.0.19 10 10019[.0]
* ...
* 1.4.21 14 10421[.0]
* 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 "rcNN".
* 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,
* <
* Y2K compliance in libpng:
* =========================
* September 28, 2017
* 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 1.4.22 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 "1.4.22"
" libpng version 1.4.22 - September 28, 2017\n"
/* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
/* This should match the numeric part of the final component of
* PNG_LIBPNG_VER_STRING, omitting any leading zero:
/* Release Status */
/* Release-Specific Flags */
#define PNG_LIBPNG_BUILD_PATCH 8 /* Can be OR'ed with
#define PNG_LIBPNG_BUILD_PRIVATE 16 /* Cannot be OR'ed with
#define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
/* 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 10422 /* 1.4.22 */
/* Include the compression library's header */
#include "zlib.h"
/* Include all user configurable info, including optional assembler routines */
#include "pngconf.h"
* Added at libpng-1.2.8
* Ref MSDN: Private as priority over Special
* VS_FF_PRIVATEBUILD File *was not* built using standard release
* procedures. If this value is given, the StringFileInfo block must
* contain a PrivateBuild string.
* VS_FF_SPECIALBUILD File *was* built by the original company using
* standard release procedures but is a variation of the standard
* file of the same version number. If this value is given, the
* StringFileInfo block must contain a SpecialBuild string.
# else
# endif
/* 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.
/* 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.
#define png_libpng_ver png_get_header_ver(NULL)
#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;
/* 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 */
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 */
} png_text;
typedef png_text FAR * png_textp;
typedef png_text FAR * FAR * png_textpp;
/* 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_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;
/* 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 */
typedef png_unknown_chunk FAR * png_unknown_chunkp;
typedef png_unknown_chunk FAR * FAR * png_unknown_chunkpp;
/* 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 PNG_DEPSTRUCT; /* width of image in pixels (from IHDR) */
png_uint_32 height PNG_DEPSTRUCT; /* height of image in pixels (from IHDR) */
png_uint_32 valid PNG_DEPSTRUCT; /* valid chunk data (see PNG_INFO_
below) */
png_size_t rowbytes PNG_DEPSTRUCT; /* bytes needed to hold an untransformed
row */
png_colorp palette PNG_DEPSTRUCT; /* array of color values
(valid & PNG_INFO_PLTE) */
png_uint_16 num_palette PNG_DEPSTRUCT; /* number of color entries in
"palette" (PLTE) */
png_uint_16 num_trans PNG_DEPSTRUCT; /* number of transparent palette
color (tRNS) */
png_byte bit_depth PNG_DEPSTRUCT; /* 1, 2, 4, 8, or 16 bits/channel
(from IHDR) */
png_byte color_type PNG_DEPSTRUCT; /* see PNG_COLOR_TYPE_ below
(from IHDR) */
/* The following three should have been named *_method not *_type */
png_byte compression_type PNG_DEPSTRUCT; /* must be
png_byte filter_type PNG_DEPSTRUCT; /* must be PNG_FILTER_TYPE_BASE
(from IHDR) */
png_byte interlace_type PNG_DEPSTRUCT; /* One of PNG_INTERLACE_NONE,
/* The following is informational only on read, and not used on writes. */
png_byte channels PNG_DEPSTRUCT; /* number of data channels per
pixel (1, 2, 3, 4) */
png_byte pixel_depth PNG_DEPSTRUCT; /* number of bits per pixel */
png_byte spare_byte PNG_DEPSTRUCT; /* to align the data, and for
future use */
png_byte signature[8] PNG_DEPSTRUCT; /* 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.
/* 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 PNG_DEPSTRUCT; /* gamma value of image,
if (valid & PNG_INFO_gAMA) */
/* GR-P, 0.96a */
/* Data valid if (valid & PNG_INFO_sRGB) non-zero. */
png_byte srgb_intent PNG_DEPSTRUCT; /* sRGB rendering intent
[0, 1, 2, or 3] */
/* 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 PNG_DEPSTRUCT; /* number of comments read/to write */
int max_text PNG_DEPSTRUCT; /* current size of text array */
png_textp text PNG_DEPSTRUCT; /* array of comments read/to write */
/* 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 PNG_DEPSTRUCT;
/* 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 PNG_DEPSTRUCT; /* significant bits in color channels */
#if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_EXPAND_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_alpha PNG_DEPSTRUCT; /* alpha values for paletted
image */
png_color_16 trans_color PNG_DEPSTRUCT; /* transparent color for
non-palette image */
/* 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 PNG_DEPSTRUCT;
/* 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 PNG_DEPSTRUCT; /* x offset on page */
png_int_32 y_offset PNG_DEPSTRUCT; /* y offset on page */
png_byte offset_unit_type PNG_DEPSTRUCT; /* offset units type */
/* 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 PNG_DEPSTRUCT; /* horizontal pixel density */
png_uint_32 y_pixels_per_unit PNG_DEPSTRUCT; /* vertical pixel density */
png_byte phys_unit_type PNG_DEPSTRUCT; /* resolution type (see
/* 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 PNG_DEPSTRUCT;
/* 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.
float x_white PNG_DEPSTRUCT;
float y_white PNG_DEPSTRUCT;
float x_red PNG_DEPSTRUCT;
float y_red PNG_DEPSTRUCT;
float x_green PNG_DEPSTRUCT;
float y_green PNG_DEPSTRUCT;
float x_blue PNG_DEPSTRUCT;
float y_blue PNG_DEPSTRUCT;
/* 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 PNG_DEPSTRUCT; /* pCAL chunk description string */
png_int_32 pcal_X0 PNG_DEPSTRUCT; /* minimum value */
png_int_32 pcal_X1 PNG_DEPSTRUCT; /* maximum value */
png_charp pcal_units PNG_DEPSTRUCT; /* Latin-1 string giving physical
units */
png_charpp pcal_params PNG_DEPSTRUCT; /* ASCII strings containing
parameter values */
png_byte pcal_type PNG_DEPSTRUCT; /* equation type
(see PNG_EQUATION_ below) */
png_byte pcal_nparams PNG_DEPSTRUCT; /* number of parameters given
in pcal_params */
/* New members added in libpng-1.0.6 */
png_uint_32 free_me PNG_DEPSTRUCT; /* flags items libpng is
responsible for freeing */
/* Storage for unknown chunks that the library doesn't recognize. */
png_unknown_chunkp unknown_chunks PNG_DEPSTRUCT;
png_size_t unknown_chunks_num PNG_DEPSTRUCT;
/* iCCP chunk data. */
png_charp iccp_name PNG_DEPSTRUCT; /* profile name */
png_charp iccp_profile PNG_DEPSTRUCT; /* International Color Consortium
profile data */
/* Note to maintainer: should be png_bytep */
png_uint_32 iccp_proflen PNG_DEPSTRUCT; /* ICC profile data length */
png_byte iccp_compression PNG_DEPSTRUCT; /* Always zero */
/* Data on sPLT chunks (there may be more than one). */
png_sPLT_tp splt_palettes PNG_DEPSTRUCT;
png_uint_32 splt_palettes_num PNG_DEPSTRUCT;
/* 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 PNG_DEPSTRUCT; /* unit of physical scale */
double scal_pixel_width PNG_DEPSTRUCT; /* width of one pixel */
double scal_pixel_height PNG_DEPSTRUCT; /* height of one pixel */
png_charp scal_s_width PNG_DEPSTRUCT; /* string containing height */
png_charp scal_s_height PNG_DEPSTRUCT; /* string containing width */
/* 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 PNG_DEPSTRUCT; /* the image bits */
png_fixed_point int_gamma PNG_DEPSTRUCT; /* gamma of image,
if (valid & PNG_INFO_gAMA) */
png_fixed_point int_x_white PNG_DEPSTRUCT;
png_fixed_point int_y_white PNG_DEPSTRUCT;
png_fixed_point int_x_red PNG_DEPSTRUCT;
png_fixed_point int_y_red PNG_DEPSTRUCT;
png_fixed_point int_x_green PNG_DEPSTRUCT;
png_fixed_point int_y_green PNG_DEPSTRUCT;
png_fixed_point int_x_blue PNG_DEPSTRUCT;
png_fixed_point int_y_blue PNG_DEPSTRUCT;
} png_info;
typedef png_info FAR * png_infop;
typedef PNG_CONST png_info FAR * png_const_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)(-1))
#define PNG_SIZE_MAX ((png_size_t)(-1))
/* These describe the color_type field in png_info. */
/* color type masks */
/* color types. Note that not all combinations are legal */
/* aliases */
/* 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 */
/* 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 */
/* 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_LAST 4 /* Not a valid value */
/* This is for text chunks */
/* Maximum number of entries in PLTE/sPLT/tRNS arrays */
/* 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_size_t 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 PNG_CONST png_struct FAR * png_const_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,
typedef void (PNGAPI *png_write_status_ptr) PNGARG((png_structp, png_uint_32,
typedef void (PNGAPI *png_progressive_info_ptr) PNGARG((png_structp,
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));
typedef void (PNGAPI *png_user_transform_ptr) PNGARG((png_structp,
png_row_infop, png_bytep));
typedef int (PNGAPI *png_user_chunk_ptr) PNGARG((png_structp,
typedef void (PNGAPI *png_unknown_chunk_ptr) PNGARG((png_structp));
/* This must match the function definition in <setjmp.h>, and the
* application must include this before png.h to obtain the definition
* of jmp_buf.
typedef void (PNGAPI *png_longjmp_ptr) PNGARG((jmp_buf, int));
/* 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 */
/* Added to libpng-1.2.34 */
#define PNG_TRANSFORM_STRIP_FILLER_AFTER 0x1000 /* write only */
/* Added to libpng-1.4.0 */
#define PNG_TRANSFORM_GRAY_TO_RGB 0x2000 /* read only */
/* Flags for MNG supported features */
#define PNG_FLAG_MNG_FILTER_64 0x04
typedef png_voidp (*png_malloc_ptr) PNGARG((png_structp, png_alloc_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
jmp_buf jmpbuf PNG_DEPSTRUCT; /* used in png_error */
png_longjmp_ptr longjmp_fn PNG_DEPSTRUCT;/* setjmp non-local goto
function. */
png_error_ptr error_fn PNG_DEPSTRUCT; /* function for printing
errors and aborting */
png_error_ptr warning_fn PNG_DEPSTRUCT; /* function for printing
warnings */
png_voidp error_ptr PNG_DEPSTRUCT; /* user supplied struct for
error functions */
png_rw_ptr write_data_fn PNG_DEPSTRUCT; /* function for writing
output data */
png_rw_ptr read_data_fn PNG_DEPSTRUCT; /* function for reading
input data */
png_voidp io_ptr PNG_DEPSTRUCT; /* ptr to application struct
for I/O functions */
png_user_transform_ptr read_user_transform_fn PNG_DEPSTRUCT; /* user read
transform */
png_user_transform_ptr write_user_transform_fn PNG_DEPSTRUCT; /* user write
transform */
/* These were added in libpng-1.0.2 */
png_voidp user_transform_ptr PNG_DEPSTRUCT; /* user supplied struct
for user transform */
png_byte user_transform_depth PNG_DEPSTRUCT; /* bit depth of user
transformed pixels */
png_byte user_transform_channels PNG_DEPSTRUCT; /* channels in user
transformed pixels */
png_uint_32 mode PNG_DEPSTRUCT; /* tells us where we are in
the PNG file */
png_uint_32 flags PNG_DEPSTRUCT; /* flags indicating various
things to libpng */
png_uint_32 transformations PNG_DEPSTRUCT; /* which transformations
to perform */
z_stream zstream PNG_DEPSTRUCT; /* pointer to decompression
structure (below) */
png_bytep zbuf PNG_DEPSTRUCT; /* buffer for zlib */
png_size_t zbuf_size PNG_DEPSTRUCT; /* size of zbuf */
int zlib_level PNG_DEPSTRUCT; /* holds zlib compression level */
int zlib_method PNG_DEPSTRUCT; /* holds zlib compression method */
int zlib_window_bits PNG_DEPSTRUCT; /* holds zlib compression window
bits */
int zlib_mem_level PNG_DEPSTRUCT; /* holds zlib compression memory
level */
int zlib_strategy PNG_DEPSTRUCT; /* holds zlib compression
strategy */
png_uint_32 width PNG_DEPSTRUCT; /* width of image in pixels */
png_uint_32 height PNG_DEPSTRUCT; /* height of image in pixels */
png_uint_32 num_rows PNG_DEPSTRUCT; /* number of rows in current pass */
png_uint_32 usr_width PNG_DEPSTRUCT; /* width of row at start of write */
png_size_t rowbytes PNG_DEPSTRUCT; /* size of row in bytes */
#if 0 /* Replaced with the following in libpng-1.4.1 */
png_size_t irowbytes PNG_DEPSTRUCT;
/* Added in libpng-1.4.1 */
/* Total memory that a zTXt, sPLT, iTXt, iCCP, or unknown chunk
* can occupy when decompressed. 0 means unlimited.
* We will change the typedef from png_size_t to png_alloc_size_t
* in libpng-1.6.0
png_alloc_size_t user_chunk_malloc_max PNG_DEPSTRUCT;
png_uint_32 iwidth PNG_DEPSTRUCT; /* width of current interlaced
row in pixels */
png_uint_32 row_number PNG_DEPSTRUCT; /* current row in interlace pass */
png_bytep prev_row PNG_DEPSTRUCT; /* buffer to save previous
(unfiltered) row */
png_bytep row_buf PNG_DEPSTRUCT; /* buffer to save current
(unfiltered) row */
png_bytep sub_row PNG_DEPSTRUCT; /* buffer to save "sub" row
when filtering */
png_bytep up_row PNG_DEPSTRUCT; /* buffer to save "up" row
when filtering */
png_bytep avg_row PNG_DEPSTRUCT; /* buffer to save "avg" row
when filtering */
png_bytep paeth_row PNG_DEPSTRUCT; /* buffer to save "Paeth" row
when filtering */
png_row_info row_info PNG_DEPSTRUCT; /* used for transformation
routines */
png_uint_32 idat_size PNG_DEPSTRUCT; /* current IDAT size for read */
png_uint_32 crc PNG_DEPSTRUCT; /* current chunk CRC value */
png_colorp palette PNG_DEPSTRUCT; /* palette from the input file */
png_uint_16 num_palette PNG_DEPSTRUCT; /* number of color entries in
palette */
png_uint_16 num_trans PNG_DEPSTRUCT; /* number of transparency values */
png_byte chunk_name[5] PNG_DEPSTRUCT; /* null-terminated name of current
chunk */
png_byte compression PNG_DEPSTRUCT; /* file compression type
(always 0) */
png_byte filter PNG_DEPSTRUCT; /* file filter type (always 0) */
png_byte interlaced PNG_DEPSTRUCT; /* PNG_INTERLACE_NONE,
png_byte pass PNG_DEPSTRUCT; /* current interlace pass (0 - 6) */
png_byte do_filter PNG_DEPSTRUCT; /* row filter flags (see
PNG_FILTER_ below ) */
png_byte color_type PNG_DEPSTRUCT; /* color type of file */
png_byte bit_depth PNG_DEPSTRUCT; /* bit depth of file */
png_byte usr_bit_depth PNG_DEPSTRUCT; /* bit depth of users row */
png_byte pixel_depth PNG_DEPSTRUCT; /* number of bits per pixel */
png_byte channels PNG_DEPSTRUCT; /* number of channels in file */
png_byte usr_channels PNG_DEPSTRUCT; /* channels at start of write */
png_byte sig_bytes PNG_DEPSTRUCT; /* magic bytes read/written from
start of file */
png_uint_16 filler PNG_DEPSTRUCT; /* filler bytes for pixel
expansion */
png_byte background_gamma_type PNG_DEPSTRUCT;
float background_gamma PNG_DEPSTRUCT;
# endif
png_color_16 background PNG_DEPSTRUCT; /* background color in
screen gamma space */
png_color_16 background_1 PNG_DEPSTRUCT; /* background normalized
to gamma 1.0 */
#endif /* PNG_bKGD_SUPPORTED */
png_flush_ptr output_flush_fn PNG_DEPSTRUCT; /* Function for flushing
output */
png_uint_32 flush_dist PNG_DEPSTRUCT; /* how many rows apart to flush,
0 - no flush */
png_uint_32 flush_rows PNG_DEPSTRUCT; /* number of rows written since
last flush */
int gamma_shift PNG_DEPSTRUCT; /* number of "insignificant" bits
16-bit gamma */
float gamma PNG_DEPSTRUCT; /* file gamma value */
float screen_gamma PNG_DEPSTRUCT; /* screen gamma value
(display_exponent) */
png_bytep gamma_table PNG_DEPSTRUCT; /* gamma table for 8-bit
depth files */
png_bytep gamma_from_1 PNG_DEPSTRUCT; /* converts from 1.0 to screen */
png_bytep gamma_to_1 PNG_DEPSTRUCT; /* converts from file to 1.0 */
png_uint_16pp gamma_16_table PNG_DEPSTRUCT; /* gamma table for 16-bit
depth files */
png_uint_16pp gamma_16_from_1 PNG_DEPSTRUCT; /* converts from 1.0 to
screen */
png_uint_16pp gamma_16_to_1 PNG_DEPSTRUCT; /* converts from file to 1.0 */
png_color_8 sig_bit PNG_DEPSTRUCT; /* significant bits in each
available channel */
png_color_8 shift PNG_DEPSTRUCT; /* shift for significant bit
tranformation */
png_bytep trans_alpha PNG_DEPSTRUCT; /* alpha values for
paletted files */
png_color_16 trans_color PNG_DEPSTRUCT; /* transparent color for
non-paletted files */
png_read_status_ptr read_row_fn PNG_DEPSTRUCT; /* called after each
row is decoded */
png_write_status_ptr write_row_fn PNG_DEPSTRUCT; /* called after each
row is encoded */
png_progressive_info_ptr info_fn PNG_DEPSTRUCT; /* called after header
data fully read */
png_progressive_row_ptr row_fn PNG_DEPSTRUCT; /* called after each
prog. row is decoded */
png_progressive_end_ptr end_fn PNG_DEPSTRUCT; /* called after image
is complete */
png_bytep save_buffer_ptr PNG_DEPSTRUCT; /* current location in
save_buffer */
png_bytep save_buffer PNG_DEPSTRUCT; /* buffer for previously
read data */
png_bytep current_buffer_ptr PNG_DEPSTRUCT; /* current location in
current_buffer */
png_bytep current_buffer PNG_DEPSTRUCT; /* buffer for recently
used data */
png_uint_32 push_length PNG_DEPSTRUCT; /* size of current input
chunk */
png_uint_32 skip_length PNG_DEPSTRUCT; /* bytes to skip in
input data */
png_size_t save_buffer_size PNG_DEPSTRUCT; /* amount of data now
in save_buffer */
png_size_t save_buffer_max PNG_DEPSTRUCT; /* total size of
save_buffer */
png_size_t buffer_size PNG_DEPSTRUCT; /* total amount of
available input data */
png_size_t current_buffer_size PNG_DEPSTRUCT; /* amount of data now
in current_buffer */
int process_mode PNG_DEPSTRUCT; /* what push library
is currently doing */
int cur_palette PNG_DEPSTRUCT; /* current push library
palette index */
png_size_t current_text_size PNG_DEPSTRUCT; /* current size of
text input data */
png_size_t current_text_left PNG_DEPSTRUCT; /* how much text left
to read in input */
png_charp current_text PNG_DEPSTRUCT; /* current text chunk
buffer */
png_charp current_text_ptr PNG_DEPSTRUCT; /* current location
in current_text */
#if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
/* For the Borland special 64K segment handler */
png_bytepp offset_table_ptr PNG_DEPSTRUCT;
png_bytep offset_table PNG_DEPSTRUCT;
png_uint_16 offset_table_number PNG_DEPSTRUCT;
png_uint_16 offset_table_count PNG_DEPSTRUCT;
png_uint_16 offset_table_count_free PNG_DEPSTRUCT;
png_bytep palette_lookup PNG_DEPSTRUCT; /* lookup table for quantizing */
png_bytep quantize_index PNG_DEPSTRUCT; /* index translation for palette
files */
png_uint_16p hist PNG_DEPSTRUCT; /* histogram */
png_charp time_buffer PNG_DEPSTRUCT; /* String to hold RFC 1123 time text */
/* New members added in libpng-1.0.6 */
png_uint_32 free_me PNG_DEPSTRUCT; /* flags items libpng is
responsible for freeing */
png_voidp user_chunk_ptr PNG_DEPSTRUCT;
png_user_chunk_ptr read_user_chunk_fn PNG_DEPSTRUCT; /* user read
chunk handler */
int num_chunk_list PNG_DEPSTRUCT;
png_bytep chunk_list PNG_DEPSTRUCT;
/* New members added in libpng-1.0.3 */
png_byte rgb_to_gray_status PNG_DEPSTRUCT;
/* These were changed from png_byte in libpng-1.0.6 */
png_uint_16 rgb_to_gray_red_coeff PNG_DEPSTRUCT;
png_uint_16 rgb_to_gray_green_coeff PNG_DEPSTRUCT;
png_uint_16 rgb_to_gray_blue_coeff PNG_DEPSTRUCT;
/* New member added in libpng-1.0.4 (renamed in 1.0.9) */
/* Changed from png_byte to png_uint_32 at version 1.2.0 */
png_uint_32 mng_features_permitted PNG_DEPSTRUCT;
/* New member added in libpng-1.0.7 */
png_fixed_point int_gamma PNG_DEPSTRUCT;
/* New member added in libpng-1.0.9, ifdef'ed out in 1.0.12, enabled in 1.2.0 */
png_byte filter_type PNG_DEPSTRUCT;
/* New members added in libpng-1.2.0 */
/* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */
png_voidp mem_ptr PNG_DEPSTRUCT; /* user supplied struct for
mem functions */
png_malloc_ptr malloc_fn PNG_DEPSTRUCT; /* function for
allocating memory */
png_free_ptr free_fn PNG_DEPSTRUCT; /* function for
freeing memory */
/* New member added in libpng-1.0.13 and 1.2.0 */
png_bytep big_row_buf PNG_DEPSTRUCT; /* buffer to save current
(unfiltered) row */
/* The following three members were added at version 1.0.14 and 1.2.4 */
png_bytep quantize_sort PNG_DEPSTRUCT; /* working sort array */
png_bytep index_to_palette PNG_DEPSTRUCT; /* where the original
index currently is
in the palette */
png_bytep palette_to_index PNG_DEPSTRUCT; /* which original index
points to this
palette color */
/* New members added in libpng-1.0.16 and 1.2.6 */
png_byte compression_type PNG_DEPSTRUCT;
png_uint_32 user_width_max PNG_DEPSTRUCT;
png_uint_32 user_height_max PNG_DEPSTRUCT;
/* Added in libpng-1.4.0: Total number of sPLT, text, and unknown
* chunks that can be stored (0 means unlimited).
png_uint_32 user_chunk_cache_max PNG_DEPSTRUCT;
/* New member added in libpng-1.0.25 and 1.2.17 */
/* Storage for unknown chunk that the library doesn't recognize. */
png_unknown_chunk unknown_chunk PNG_DEPSTRUCT;
/* New members added in libpng-1.2.26 */
png_uint_32 old_big_row_buf_size PNG_DEPSTRUCT;
png_uint_32 old_prev_row_size PNG_DEPSTRUCT;
/* New member added in libpng-1.2.30 */
png_charp chunkdata PNG_DEPSTRUCT; /* buffer for reading chunk data */
/* New member added in libpng-1.4.0 */
png_uint_32 io_state PNG_DEPSTRUCT;
/* 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_4_22;
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 */
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.
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).
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).
#define png_check_sig(sig,n) !png_sig_cmp((sig), 0, (n))
/* Allocate and initialize png_ptr struct for reading, and any other memory. */
PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,
png_error_ptr error_fn, png_error_ptr warn_fn)) PNG_ALLOCATED;
/* Allocate and initialize png_ptr struct for writing, and any other memory */
PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,
png_error_ptr error_fn, png_error_ptr warn_fn)) PNG_ALLOCATED;
PNGARG((png_const_structp png_ptr));
PNGARG((png_structp png_ptr, png_size_t size));
/* Moved from pngconf.h in 1.4.0 and modified to ensure setjmp/longjmp
* match up.
/* This function returns the jmp_buf built in to *png_ptr. It must be
* supplied with an appropriate 'longjmp' function to use on that jmp_buf
* unless the default error function is overridden in which case NULL is
* acceptable. The size of the jmp_buf is checked against the actual size
* allocated by the library - the call will return NULL on a mismatch
* indicating an ABI mismatch.
PNG_EXPORT(jmp_buf*, png_set_longjmp_fn)
PNGARG((png_structp png_ptr, png_longjmp_ptr longjmp_fn, size_t
# define png_jmpbuf(png_ptr) \
(*png_set_longjmp_fn((png_ptr), longjmp, sizeof (jmp_buf)))
# define png_jmpbuf(png_ptr) \
/* Reset the compression stream */
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) */
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)) PNG_ALLOCATED;
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)) PNG_ALLOCATED;
/* Write the PNG file signature. */
PNG_EXPORT(void,png_write_sig) PNGARG((png_structp png_ptr));
/* Write a PNG chunk - size, type, (optional) data, CRC. */
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. */
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(). */
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). */
PNG_EXPORT(void,png_write_chunk_end) PNGARG((png_structp png_ptr));
/* Allocate and initialize the info structure */
PNGARG((png_structp png_ptr)) PNG_ALLOCATED;
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. */
PNG_EXPORT(void,png_write_info_before_PLTE) PNGARG((png_structp png_ptr,
png_infop info_ptr));
PNG_EXPORT(void,png_write_info) PNGARG((png_structp png_ptr,
png_infop info_ptr));
/* Read the information before the actual image data. */
PNG_EXPORT(void,png_read_info) PNGARG((png_structp png_ptr,
png_infop info_ptr));
PNGARG((png_structp png_ptr, png_timep ptime));
/* Convert from a struct tm to png_time */
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() */
PNG_EXPORT(void,png_convert_from_time_t) PNGARG((png_timep ptime,
time_t ttime));
/* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */
PNG_EXPORT(void,png_set_expand) PNGARG((png_structp png_ptr));
PNG_EXPORT(void,png_set_expand_gray_1_2_4_to_8) PNGARG((png_structp
PNG_EXPORT(void,png_set_palette_to_rgb) PNGARG((png_structp png_ptr));
PNG_EXPORT(void,png_set_tRNS_to_alpha) PNGARG((png_structp png_ptr));
/* Use blue, green, red order for pixels. */
PNG_EXPORT(void,png_set_bgr) PNGARG((png_structp png_ptr));
/* Expand the grayscale to 24-bit RGB if necessary. */
PNG_EXPORT(void,png_set_gray_to_rgb) PNGARG((png_structp png_ptr));
/* Reduce RGB to grayscale. */
PNG_EXPORT(void,png_set_rgb_to_gray) PNGARG((png_structp png_ptr,
int error_action, double red, double green ));
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 ));
PNG_EXPORT(png_byte,png_get_rgb_to_gray_status) PNGARG((png_const_structp
PNG_EXPORT(void,png_build_grayscale_palette) PNGARG((int bit_depth,
png_colorp palette));
PNG_EXPORT(void,png_set_strip_alpha) PNGARG((png_structp png_ptr));
PNG_EXPORT(void,png_set_swap_alpha) PNGARG((png_structp png_ptr));
PNG_EXPORT(void,png_set_invert_alpha) PNGARG((png_structp png_ptr));
/* Add a filler byte to 8-bit Gray or 24-bit RGB images. */
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 */
/* Add an alpha byte to 8-bit Gray or 24-bit RGB images. */
PNG_EXPORT(void,png_set_add_alpha) PNGARG((png_structp png_ptr,
png_uint_32 filler, int flags));
/* Swap bytes in 16-bit depth files. */
PNG_EXPORT(void,png_set_swap) PNGARG((png_structp png_ptr));
/* Use 1 byte per pixel in 1, 2, or 4-bit depth files. */
PNG_EXPORT(void,png_set_packing) PNGARG((png_structp png_ptr));
/* Swap packing order of pixels in bytes. */
PNG_EXPORT(void,png_set_packswap) PNGARG((png_structp png_ptr));
/* Converts files to legal bit depths. */
PNG_EXPORT(void,png_set_shift) PNGARG((png_structp png_ptr,
png_color_8p true_bits));
/* Have the code handle the interlacing. Returns the number of passes. */
PNG_EXPORT(int,png_set_interlace_handling) PNGARG((png_structp png_ptr));
/* Invert monochrome files */
PNG_EXPORT(void,png_set_invert_mono) PNGARG((png_structp png_ptr));
/* Handle alpha and tRNS by replacing with a background color. */
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));
/* Strip the second byte of information from a 16-bit depth file. */
PNG_EXPORT(void,png_set_strip_16) PNGARG((png_structp png_ptr));
/* Turn on quantizing, and reduce the palette to the number of colors
* available. Prior to libpng-1.4.2, this was png_set_dither().
PNG_EXPORT(void,png_set_quantize) PNGARG((png_structp png_ptr,
png_colorp palette, int num_palette, int maximum_colors,
png_uint_16p histogram, int full_quantize));
/* This migration aid will be removed from libpng-1.5.0 */
#define png_set_dither png_set_quantize
/* Handle gamma correction. Screen_gamma=(display_exponent) */
PNG_EXPORT(void,png_set_gamma) PNGARG((png_structp png_ptr,
double screen_gamma, double default_file_gamma));
/* Set how many lines between output flushes - 0 for no flushing */
PNG_EXPORT(void,png_set_flush) PNGARG((png_structp png_ptr, int nrows));
/* Flush the current PNG output buffer */
PNG_EXPORT(void,png_write_flush) PNGARG((png_structp png_ptr));
/* Optional update palette with requested transformations */
PNG_EXPORT(void,png_start_read_image) PNGARG((png_structp png_ptr));
/* Optional call to update the users info structure */
PNG_EXPORT(void,png_read_update_info) PNGARG((png_structp png_ptr,
png_infop info_ptr));
/* Read one or more rows of image data. */
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. */
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. */
PNG_EXPORT(void,png_read_image) PNGARG((png_structp png_ptr,
png_bytepp image));
/* Write a row of image data */
PNG_EXPORT(void,png_write_row) PNGARG((png_structp png_ptr,
png_bytep row));
/* Write a few rows of image data */
PNG_EXPORT(void,png_write_rows) PNGARG((png_structp png_ptr,
png_bytepp row, png_uint_32 num_rows));
/* Write the image data */
PNG_EXPORT(void,png_write_image) PNGARG((png_structp png_ptr,
png_bytepp image));
/* Write the end of the PNG file. */
PNG_EXPORT(void,png_write_end) PNGARG((png_structp png_ptr,
png_infop info_ptr));
/* Read the end of the PNG file. */
PNG_EXPORT(void,png_read_end) PNGARG((png_structp png_ptr,
png_infop info_ptr));
/* Free any memory associated with the png_info_struct */
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 */
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 any memory associated with the png_struct and the png_info_structs */
PNGARG((png_structpp png_ptr_ptr, png_infopp info_ptr_ptr));
/* Set the libpng method of handling chunk CRC errors */
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.
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
/* Filter values (not flags) - used in pngwrite.c, pngwutil.c for now.
* These defines should NOT be changed.
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));
/* The following are no longer used and will be removed from libpng-1.7: */
#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.
PNG_EXPORT(void,png_set_compression_level) PNGARG((png_structp png_ptr,
int level));
PNGARG((png_structp png_ptr, int mem_level));
PNGARG((png_structp png_ptr, int strategy));
PNGARG((png_structp png_ptr, int window_bits));
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.
/* Initialize the input/output for the PNG file to the default functions. */
PNG_EXPORT(void,png_init_io) PNGARG((png_structp png_ptr,
png_FILE_p fp));
/* 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.
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 */
PNG_EXPORT(png_voidp,png_get_error_ptr) PNGARG((png_const_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).
* It is probably a mistake to use NULL for output_flush_fn if
* write_data_fn is not also NULL unless you have built libpng with
* PNG_WRITE_FLUSH_SUPPORTED undefined, because in this case libpng's
* default flush function, which uses the standard *FILE structure, will
* be used.
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. */
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 */
PNG_EXPORT(png_voidp,png_get_io_ptr) PNGARG((png_structp png_ptr));
PNG_EXPORT(void,png_set_read_status_fn) PNGARG((png_structp png_ptr,
png_read_status_ptr read_row_fn));
PNG_EXPORT(void,png_set_write_status_fn) PNGARG((png_structp png_ptr,
png_write_status_ptr write_row_fn));
/* Replace the default memory allocation functions with user supplied one(s). */
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 */
PNG_EXPORT(png_voidp,png_get_mem_ptr) PNGARG((png_const_structp png_ptr));
PNG_EXPORT(void,png_set_read_user_transform_fn) PNGARG((png_structp
png_ptr, png_user_transform_ptr read_user_transform_fn));
PNG_EXPORT(void,png_set_write_user_transform_fn) PNGARG((png_structp
png_ptr, png_user_transform_ptr write_user_transform_fn));
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 */
PNGARG((png_const_structp png_ptr));
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));
PNG_EXPORT(png_voidp,png_get_user_chunk_ptr) PNGARG((png_const_structp
/* Sets the function callbacks for the push reader, and a pointer to a
* user-defined structure available to the callback functions.
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 */
PNGARG((png_const_structp png_ptr));
/* Function to be called when data becomes available */
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?????
PNG_EXPORT(void,png_progressive_combine_row) PNGARG((png_structp png_ptr,
png_bytep old_row, png_bytep new_row));
PNG_EXPORT(png_voidp,png_malloc) PNGARG((png_structp png_ptr,
png_alloc_size_t size)) PNG_ALLOCATED;
/* Added at libpng version 1.4.0 */
PNG_EXPORT(png_voidp,png_calloc) PNGARG((png_structp png_ptr,
png_alloc_size_t size)) PNG_ALLOCATED;
/* Added at libpng version 1.2.4 */
PNG_EXPORT(png_voidp,png_malloc_warn) PNGARG((png_structp png_ptr,
png_alloc_size_t size)) PNG_ALLOCATED;
/* Frees a pointer allocated by png_malloc() */
PNG_EXPORT(void,png_free) PNGARG((png_structp png_ptr, png_voidp ptr));
/* Free data that was allocated internally */
PNG_EXPORT(void,png_free_data) PNGARG((png_structp png_ptr,
png_infop info_ptr, png_uint_32 free_me, int num));
/* Reassign responsibility for freeing existing data, whether allocated
* by libpng or by the application */
PNG_EXPORT(void,png_data_freer) PNGARG((png_structp png_ptr,
png_infop info_ptr, int freer, png_uint_32 mask));
/* Assignments for png_data_freer */
/* 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
PNG_EXPORT(png_voidp,png_malloc_default) PNGARG((png_structp png_ptr,
png_alloc_size_t size)) PNG_ALLOCATED;
PNG_EXPORT(void,png_free_default) PNGARG((png_structp png_ptr,
png_voidp ptr));
/* Fatal error in PNG image of libpng - can't continue */
PNG_EXPORT(void,png_error) PNGARG((png_structp png_ptr,
png_const_charp error_message)) PNG_NORETURN;
/* The same, but the chunk name is prepended to the error string. */
PNG_EXPORT(void,png_chunk_error) PNGARG((png_structp png_ptr,
png_const_charp error_message)) PNG_NORETURN;
/* Fatal error in PNG image of libpng - can't continue */
PNG_EXPORT(void,png_err) PNGARG((png_structp png_ptr)) PNG_NORETURN;
/* Non-fatal error in libpng. Can continue, but may have a problem. */
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. */
PNG_EXPORT(void,png_chunk_warning) PNGARG((png_structp png_ptr,
png_const_charp warning_message));
/* Benign error in libpng. Can continue, but may have a problem.
* User can choose whether to handle as a fatal error or as a warning. */
PNG_EXPORT(void,png_benign_error) PNGARG((png_structp png_ptr,
png_const_charp warning_message));
/* Same, chunk name is prepended to message. */
PNG_EXPORT(void,png_chunk_benign_error) PNGARG((png_structp png_ptr,
png_const_charp warning_message));
PNG_EXPORT(void,png_set_benign_errors) PNGARG((png_structp
png_ptr, int allowed));
/* 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. */
PNG_EXPORT(png_uint_32,png_get_valid) PNGARG((png_const_structp png_ptr,
png_const_infop info_ptr, png_uint_32 flag));
/* Returns number of bytes needed to hold a transformed row. */
PNG_EXPORT(png_size_t,png_get_rowbytes) PNGARG((png_const_structp png_ptr,
png_const_infop info_ptr));
/* Returns row_pointers, which is an array of pointers to scanlines that was
* returned from png_read_png().
PNG_EXPORT(png_bytepp,png_get_rows) PNGARG((png_const_structp png_ptr,
png_const_infop info_ptr));
/* Set row_pointers, which is an array of pointers to scanlines for use
* by png_write_png().
PNG_EXPORT(void,png_set_rows) PNGARG((png_structp png_ptr,
png_infop info_ptr, png_bytepp row_pointers));
/* Returns number of color channels in image. */
PNG_EXPORT(png_byte,png_get_channels) PNGARG((png_const_structp png_ptr,
png_const_infop info_ptr));
/* Returns image width in pixels. */
PNG_EXPORT(png_uint_32, png_get_image_width) PNGARG((png_const_structp
png_ptr, png_const_infop info_ptr));
/* Returns image height in pixels. */
PNG_EXPORT(png_uint_32, png_get_image_height) PNGARG((png_const_structp
png_ptr, png_const_infop info_ptr));
/* Returns image bit_depth. */
PNG_EXPORT(png_byte, png_get_bit_depth) PNGARG((png_const_structp
png_ptr, png_const_infop info_ptr));
/* Returns image color_type. */
PNG_EXPORT(png_byte, png_get_color_type) PNGARG((png_const_structp
png_ptr, png_const_infop info_ptr));
/* Returns image filter_type. */
PNG_EXPORT(png_byte, png_get_filter_type) PNGARG((png_const_structp
png_ptr, png_const_infop info_ptr));
/* Returns image interlace_type. */
PNG_EXPORT(png_byte, png_get_interlace_type) PNGARG((png_const_structp
png_ptr, png_const_infop info_ptr));
/* Returns image compression_type. */
PNG_EXPORT(png_byte, png_get_compression_type) PNGARG((png_const_structp
png_ptr, png_const_infop info_ptr));
/* Returns image resolution in pixels per meter, from pHYs chunk data. */
PNG_EXPORT(png_uint_32, png_get_pixels_per_meter) PNGARG((png_const_structp
png_ptr, png_const_infop info_ptr));
PNG_EXPORT(png_uint_32, png_get_x_pixels_per_meter) PNGARG((png_const_structp
png_ptr, png_const_infop info_ptr));
PNG_EXPORT(png_uint_32, png_get_y_pixels_per_meter) PNGARG((png_const_structp
png_ptr, png_const_infop info_ptr));
/* Returns pixel aspect ratio, computed from pHYs chunk data. */
PNG_EXPORT(float, png_get_pixel_aspect_ratio) PNGARG((png_const_structp
png_ptr, png_const_infop info_ptr));
/* Returns image x, y offset in pixels or microns, from oFFs chunk data. */
PNG_EXPORT(png_int_32, png_get_x_offset_pixels) PNGARG((png_const_structp
png_ptr, png_const_infop info_ptr));
PNG_EXPORT(png_int_32, png_get_y_offset_pixels) PNGARG((png_const_structp
png_ptr, png_const_infop info_ptr));
PNG_EXPORT(png_int_32, png_get_x_offset_microns) PNGARG((png_const_structp
png_ptr, png_const_infop info_ptr));
PNG_EXPORT(png_int_32, png_get_y_offset_microns) PNGARG((png_const_structp
png_ptr, png_const_infop info_ptr));
/* Returns pointer to signature string read from PNG header */
PNG_EXPORT(png_bytep,png_get_signature) PNGARG((png_const_structp png_ptr,
png_infop info_ptr));
PNG_EXPORT(png_uint_32,png_get_bKGD) PNGARG((png_const_structp png_ptr,
png_infop info_ptr, png_color_16p *background));
PNG_EXPORT(void,png_set_bKGD) PNGARG((png_structp png_ptr,
png_infop info_ptr, png_color_16p background));
PNG_EXPORT(png_uint_32,png_get_cHRM) PNGARG((png_const_structp png_ptr,
png_const_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));
PNG_EXPORT(png_uint_32,png_get_cHRM_fixed) PNGARG((png_const_structp png_ptr,
png_const_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));
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));
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));
PNG_EXPORT(png_uint_32,png_get_gAMA) PNGARG((png_const_structp png_ptr,
png_const_infop info_ptr, double *file_gamma));
PNG_EXPORT(png_uint_32,png_get_gAMA_fixed) PNGARG((png_const_structp png_ptr,
png_const_infop info_ptr, png_fixed_point *int_file_gamma));
PNG_EXPORT(void,png_set_gAMA) PNGARG((png_structp png_ptr,
png_infop info_ptr, double file_gamma));
PNG_EXPORT(void,png_set_gAMA_fixed) PNGARG((png_structp png_ptr,
png_infop info_ptr, png_fixed_point int_file_gamma));
PNG_EXPORT(png_uint_32,png_get_hIST) PNGARG((png_const_structp png_ptr,
png_const_infop info_ptr, png_uint_16p *hist));
PNG_EXPORT(void,png_set_hIST) PNGARG((png_structp png_ptr,
png_infop info_ptr, png_uint_16p hist));
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));
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));
PNG_EXPORT(png_uint_32,png_get_oFFs) PNGARG((png_const_structp png_ptr,
png_const_infop info_ptr, png_int_32 *offset_x, png_int_32 *offset_y,
int *unit_type));
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));
PNG_EXPORT(png_uint_32,png_get_pCAL) PNGARG((png_const_structp png_ptr,
png_const_infop info_ptr, png_charp *purpose, png_int_32 *X0, png_int_32 *X1,
int *type, int *nparams, png_charp *units, png_charpp *params));
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));
PNG_EXPORT(png_uint_32,png_get_pHYs) PNGARG((png_const_structp png_ptr,
png_const_infop info_ptr, png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type));
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));
PNG_EXPORT(png_uint_32,png_get_PLTE) PNGARG((png_const_structp png_ptr,
png_const_infop info_ptr, png_colorp *palette, int *num_palette));
PNG_EXPORT(void,png_set_PLTE) PNGARG((png_structp png_ptr,
png_infop info_ptr, png_colorp palette, int num_palette));
PNG_EXPORT(png_uint_32,png_get_sBIT) PNGARG((png_const_structp png_ptr,
png_infop info_ptr, png_color_8p *sig_bit));
PNG_EXPORT(void,png_set_sBIT) PNGARG((png_structp png_ptr,
png_infop info_ptr, png_color_8p sig_bit));
PNG_EXPORT(png_uint_32,png_get_sRGB) PNGARG((png_const_structp png_ptr,
png_const_infop info_ptr, int *intent));
PNG_EXPORT(void,png_set_sRGB) PNGARG((png_structp png_ptr,
png_infop info_ptr, int intent));
PNG_EXPORT(void,png_set_sRGB_gAMA_and_cHRM) PNGARG((png_structp png_ptr,
png_infop info_ptr, int intent));
PNG_EXPORT(png_uint_32,png_get_iCCP) PNGARG((png_const_structp png_ptr,
png_const_infop info_ptr, png_charpp name, int *compression_type,
png_charpp profile, png_uint_32 *proflen));
/* Note to maintainer: profile should be png_bytepp */
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 */
PNG_EXPORT(png_uint_32,png_get_sPLT) PNGARG((png_const_structp png_ptr,
png_const_infop info_ptr, png_sPLT_tpp entries));
PNG_EXPORT(void,png_set_sPLT) PNGARG((png_structp png_ptr,
png_infop info_ptr, png_sPLT_tp entries, int nentries));
/* png_get_text also returns the number of text chunks in *num_text */
PNG_EXPORT(png_uint_32,png_get_text) PNGARG((png_const_structp png_ptr,
png_const_infop info_ptr, png_textp *text_ptr, int *num_text));
/* 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.
PNG_EXPORT(void,png_set_text) PNGARG((png_structp png_ptr,
png_infop info_ptr, png_textp text_ptr, int num_text));
PNG_EXPORT(png_uint_32,png_get_tIME) PNGARG((png_const_structp png_ptr,
png_infop info_ptr, png_timep *mod_time));
PNG_EXPORT(void,png_set_tIME) PNGARG((png_structp png_ptr,
png_infop info_ptr, png_timep mod_time));
PNG_EXPORT(png_uint_32,png_get_tRNS) PNGARG((png_const_structp png_ptr,
png_infop info_ptr, png_bytep *trans_alpha, int *num_trans,
png_color_16p *trans_color));
PNG_EXPORT(void,png_set_tRNS) PNGARG((png_structp png_ptr,
png_infop info_ptr, png_bytep trans_alpha, int num_trans,
png_color_16p trans_color));
PNG_EXPORT(png_uint_32,png_get_sCAL) PNGARG((png_const_structp png_ptr,
png_const_infop info_ptr, int *unit, double *width, double *height));
PNG_EXPORT(png_uint_32,png_get_sCAL_s) PNGARG((png_const_structp png_ptr,
png_const_infop info_ptr, int *unit, png_charpp swidth, png_charpp sheight));
#endif /* PNG_sCAL_SUPPORTED */
PNG_EXPORT(void,png_set_sCAL) PNGARG((png_structp png_ptr,
png_infop info_ptr, int unit, double width, double height));
PNG_EXPORT(void,png_set_sCAL_s) PNGARG((png_structp png_ptr,
png_infop info_ptr, int unit, png_charp swidth, png_charp sheight));
/* 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 behaviour
= 1: do not keep
= 2: keep only if safe-to-copy
= 3: keep even if unsafe-to-copy
PNG_EXPORT(void, png_set_keep_unknown_chunks) PNGARG((png_structp
png_ptr, int keep, png_bytep chunk_list, int num_chunks));
PNG_EXPORT(int,png_handle_as_unknown) PNGARG((png_structp png_ptr, png_bytep
PNG_EXPORT(void, png_set_unknown_chunks) PNGARG((png_structp png_ptr,
png_infop info_ptr, png_unknown_chunkp unknowns, int num_unknowns));
PNG_EXPORT(void, png_set_unknown_chunk_location)
PNGARG((png_structp png_ptr, png_infop info_ptr, int chunk, int location));
PNG_EXPORT(png_uint_32,png_get_unknown_chunks) PNGARG((png_const_structp
png_ptr, png_const_infop info_ptr, png_unknown_chunkpp entries));
/* 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);
PNG_EXPORT(void, png_set_invalid) PNGARG((png_structp png_ptr,
png_infop info_ptr, int mask));
/* The "params" pointer is currently not used and is for future expansion. */
PNG_EXPORT(void, png_read_png) PNGARG((png_structp png_ptr,
png_infop info_ptr,
int transforms,
png_voidp params));
PNG_EXPORT(void, png_write_png) PNGARG((png_structp png_ptr,
png_infop info_ptr,
int transforms,
png_voidp params));
PNG_EXPORT(png_charp,png_get_copyright) PNGARG((png_const_structp png_ptr));
PNG_EXPORT(png_charp,png_get_header_ver) PNGARG((png_const_structp png_ptr));
PNG_EXPORT(png_charp,png_get_header_version) PNGARG((png_const_structp
PNG_EXPORT(png_charp,png_get_libpng_ver) PNGARG((png_const_structp png_ptr));
PNG_EXPORT(png_uint_32,png_permit_mng_features) PNGARG((png_structp
png_ptr, png_uint_32 mng_features_permitted));
/* For use in png_set_keep_unknown, added to version 1.2.6 */
/* Strip the prepended error numbers ("#nnn ") from error and warning
* messages before passing them to the error or warning handler.
PNG_EXPORT(void,png_set_strip_error_numbers) PNGARG((png_structp
png_ptr, png_uint_32 strip_mode));
/* Added in libpng-1.2.6 */
PNG_EXPORT(void,png_set_user_limits) PNGARG((png_structp
png_ptr, png_uint_32 user_width_max, png_uint_32 user_height_max));
PNG_EXPORT(png_uint_32,png_get_user_width_max) PNGARG((png_const_structp
PNG_EXPORT(png_uint_32,png_get_user_height_max) PNGARG((png_const_structp
/* Added in libpng-1.4.0 */
PNG_EXPORT(void,png_set_chunk_cache_max) PNGARG((png_structp
png_ptr, png_uint_32 user_chunk_cache_max));
PNGARG((png_const_structp png_ptr));
/* Added in libpng-1.4.1 */
PNG_EXPORT(void,png_set_chunk_malloc_max) PNGARG((png_structp
png_ptr, png_alloc_size_t user_chunk_cache_max));
PNGARG((png_const_structp png_ptr));
PNGARG((png_const_structp png_ptr, png_const_infop info_ptr));
PNGARG((png_const_structp png_ptr, png_const_infop info_ptr));
PNGARG((png_const_structp png_ptr, png_const_infop info_ptr));
PNG_EXPORT(float,png_get_x_offset_inches) PNGARG((png_const_structp png_ptr,
png_const_infop info_ptr));
PNG_EXPORT(float,png_get_y_offset_inches) PNGARG((png_const_structp png_ptr,
png_const_infop info_ptr));
PNG_EXPORT(png_uint_32,png_get_pHYs_dpi) PNGARG((png_const_structp png_ptr,
png_const_infop info_ptr, png_uint_32 *res_x, png_uint_32 *res_y,
int *unit_type));
#endif /* PNG_pHYs_SUPPORTED */
/* Added in libpng-1.4.0 */
PNG_EXPORT(png_uint_32,png_get_io_state) PNGARG((png_const_structp png_ptr));
PNGARG((png_structp png_ptr));
/* The flags returned by png_get_io_state() are the following: */
#define PNG_IO_NONE 0x0000 /* no I/O at this moment */
#define PNG_IO_READING 0x0001 /* currently reading */
#define PNG_IO_WRITING 0x0002 /* currently writing */
#define PNG_IO_SIGNATURE 0x0010 /* currently at the file signature */
#define PNG_IO_CHUNK_HDR 0x0020 /* currently at the chunk header */
#define PNG_IO_CHUNK_DATA 0x0040 /* currently at the chunk data */
#define PNG_IO_CHUNK_CRC 0x0080 /* currently at the chunk crc */
#define PNG_IO_MASK_OP 0x000f /* current operation: reading/writing */
#define PNG_IO_MASK_LOC 0x00f0 /* current location: sig/hdr/data/crc */
/* Maintainer: Put new public prototypes here ^, in libpng.3, and project
* defs
/* 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)
/* Inline macros to do direct reads of bytes from the input buffer.
* The png_get_int_32() routine assumes we are using two's complement
* format for negative values, which is almost certainly true.
# define png_get_uint_32(buf) \
(((png_uint_32)((*(buf)) & 0xff) << 24) + \
((png_uint_32)((*((buf) + 1)) & 0xff) << 16) + \
((png_uint_32)((*((buf) + 2)) & 0xff) << 8) + \
((png_uint_32)((*((buf) + 3)) & 0xff)))
/* The following definition introduces an API incompatibility (but not
* an ABI incompatibility) with libpng-1.4.0 through 1.4.4. Prior to
* libpng-1.4.5 the macro, which is used by default, returned (incorrectly)
* a (png_uint_32), while the function, if used instead, correctly returned
* a (png_uint_16).
* Libpng versions 1.0.x and 1.2.x only used a function so are not affected
* by this potential API incompatibility between macros.
# define png_get_uint_16(buf) \
((png_uint_16) \
(((unsigned int)(*(buf)) << 8) + \
((unsigned int)(*((buf) + 1)))))
# define png_get_int_32(buf) \
((png_int_32)((*(buf) & 0x80) \
? -((png_int_32)(((png_get_uint_32(buf)^0xffffffffU)+1U)&0x7fffffffU)) \
: (png_int_32)png_get_uint_32(buf)))
PNG_EXPORT(png_uint_32,png_get_uint_32) PNGARG((png_bytep buf));
PNG_EXPORT(png_uint_16,png_get_uint_16) PNGARG((png_bytep buf));
PNG_EXPORT(png_int_32,png_get_int_32) PNGARG((png_bytep buf));
PNGARG((png_structp png_ptr, png_bytep buf));
/* No png_get_int_16 -- may be added if there's a real need for it. */
/* Place a 32-bit number into a buffer in PNG byte order (big-endian). */
PNGARG((png_bytep buf, png_uint_32 i));
PNGARG((png_bytep buf, png_int_32 i));
/* 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.
PNGARG((png_bytep buf, unsigned int i));
/* No png_save_int_16 -- may be added if there's a real need for it. */
/* ************************************************************************* */
/* 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 /* Have complete zlib datastream */
#define PNG_HAVE_IEND 0x10
#define PNG_HAVE_gAMA 0x20
#define PNG_HAVE_cHRM 0x40
#ifdef __cplusplus
/* Do not put anything past this line */
#endif /* PNG_H */