png.h

GIS系统支持库Geospatial Data Abstraction Library代码.GDAL is a translator library for raster geospatial dat

 *
 *       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 "1.2.8"
#define PNG_HEADER_VERSION_STRING \
   " libpng version 1.2.8 - December 3, 2004 (header)\n"

#define PNG_LIBPNG_VER_SONUM   0
#define PNG_LIBPNG_VER_DLLNUM  13

/* 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 8
/* This should match the numeric part of the final component of
 * PNG_LIBPNG_VER_STRING, omitting any leading zero: */

#define PNG_LIBPNG_VER_BUILD  0

/* Release Status */
#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_RELEASE_STATUS_MASK 7
  
/* Release-Specific Flags */
#define PNG_LIBPNG_BUILD_PATCH    8 /* Can be OR'ed with
                                       PNG_LIBPNG_BUILD_STABLE only */
#define PNG_LIBPNG_BUILD_PRIVATE 16 /* Cannot be OR'ed with
                                       PNG_LIBPNG_BUILD_SPECIAL */
#define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
                                       PNG_LIBPNG_BUILD_PRIVATE */

#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_STABLE

/* 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 10208 /* 1.2.8 */

#ifndef PNG_VERSION_INFO_ONLY
/* include the compression library's header */
#include "zlib.h"
#endif

/* 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. 
 */

#if defined(PNG_USER_PRIVATEBUILD)
#  define PNG_LIBPNG_BUILD_TYPE PNG_LIBPNG_BUILD_BASE_TYPE | \
          PNG_LIBPNG_BUILD_PRIVATE
#else
#  if defined(PNG_LIBPNG_SPECIALBUILD)
#    define PNG_LIBPNG_BUILD_TYPE PNG_LIBPNG_BUILD_BASE_TYPE | \
            PNG_LIBPNG_BUILD_SPECIAL
#  else
#    define PNG_LIBPNG_BUILD_TYPE PNG_LIBPNG_BUILD_BASE_TYPE
#  endif
#endif

#ifndef PNG_VERSION_INFO_ONLY

/* 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
{