Image::PNG::Const(3)

NAME
Image::PNG::Const - Constants for libpng

SYNOPSIS
    # Get just the constants you need:
    use Image::PNG::Const qw/PNG_TRANSFORM_INVERT_ALPHA
                             PNG_COLOR_MASK_ALPHA/;
    # Get everything:
    use Image::PNG::Const ':all';

This module is a helper for Image::PNG::Libpng. It contains no functions, only constants.

CONSTANTS
This file contains the following constants, from the header file of the PNG library, "png.h":

PNG_AFTER_IDAT
    PNG_AFTER_IDAT has value 0x08.

PNG_ALL_FILTERS
    PNG_ALL_FILTERS has value ((0x08 | 0x10 | 0x20) | 0x40 | 0x80).

PNG_ALL_MNG_FEATURES
    PNG_ALL_MNG_FEATURES has value 0x05.

PNG_ALPHA_ASSOCIATED
    PNG_ALPHA_ASSOCIATED has value 1.

PNG_ALPHA_BROKEN
    PNG_ALPHA_BROKEN has value 3.

PNG_ALPHA_OPTIMIZED
    PNG_ALPHA_OPTIMIZED has value 2.

PNG_ALPHA_PNG
    PNG_ALPHA_PNG has value 0.

PNG_ALPHA_PREMULTIPLIED
    PNG_ALPHA_PREMULTIPLIED has value 1.

PNG_ALPHA_STANDARD
    PNG_ALPHA_STANDARD has value 1.

PNG_ARM_NEON
    PNG_ARM_NEON has value 0.

PNG_BACKGROUND_GAMMA_FILE
    PNG_BACKGROUND_GAMMA_FILE has value 2.

PNG_BACKGROUND_GAMMA_SCREEN
    PNG_BACKGROUND_GAMMA_SCREEN has value 1.

PNG_BACKGROUND_GAMMA_UNIQUE
    PNG_BACKGROUND_GAMMA_UNIQUE has value 3.

PNG_BACKGROUND_GAMMA_UNKNOWN
    PNG_BACKGROUND_GAMMA_UNKNOWN has value 0.

PNG_BLEND_OP_OVER
    PNG_BLEND_OP_OVER has value 0x01.

PNG_BLEND_OP_SOURCE
    PNG_BLEND_OP_SOURCE has value 0x00.

PNG_COLOR_MASK_ALPHA
    PNG_COLOR_MASK_ALPHA has value 4.

PNG_COLOR_MASK_COLOR
    PNG_COLOR_MASK_COLOR has value 2.

PNG_COLOR_MASK_PALETTE
    PNG_COLOR_MASK_PALETTE has value 1.

PNG_COLOR_TYPE_GA
    PNG_COLOR_TYPE_GA has value (4).

PNG_COLOR_TYPE_GRAY
    PNG_COLOR_TYPE_GRAY has value 0.

PNG_COLOR_TYPE_GRAY_ALPHA
    PNG_COLOR_TYPE_GRAY_ALPHA has value (4).

PNG_COLOR_TYPE_PALETTE
    PNG_COLOR_TYPE_PALETTE has value (2 | 1).

PNG_COLOR_TYPE_RGB
    PNG_COLOR_TYPE_RGB has value (2).

PNG_COLOR_TYPE_RGBA
    PNG_COLOR_TYPE_RGBA has value (2 | 4).

PNG_COLOR_TYPE_RGB_ALPHA
    PNG_COLOR_TYPE_RGB_ALPHA has value (2 | 4).

PNG_COMPRESSION_TYPE_BASE
    PNG_COMPRESSION_TYPE_BASE has value 0.

PNG_COMPRESSION_TYPE_DEFAULT
    PNG_COMPRESSION_TYPE_DEFAULT has value 0.

PNG_CRC_DEFAULT
    PNG_CRC_DEFAULT has value 0.

PNG_CRC_ERROR_QUIT
    PNG_CRC_ERROR_QUIT has value 1.

PNG_CRC_NO_CHANGE
    PNG_CRC_NO_CHANGE has value 5.

PNG_CRC_QUIET_USE
    PNG_CRC_QUIET_USE has value 4.

PNG_CRC_WARN_DISCARD
    PNG_CRC_WARN_DISCARD has value 2.

PNG_CRC_WARN_USE
    PNG_CRC_WARN_USE has value 3.

PNG_DEFAULT_sRGB
    PNG_DEFAULT_sRGB has value -1.

PNG_DISPOSE_OP_BACKGROUND
    PNG_DISPOSE_OP_BACKGROUND has value 0x01.

PNG_DISPOSE_OP_NONE
    PNG_DISPOSE_OP_NONE has value 0x00.

PNG_DISPOSE_OP_PREVIOUS
    PNG_DISPOSE_OP_PREVIOUS has value 0x02.

PNG_EQUATION_ARBITRARY
    PNG_EQUATION_ARBITRARY has value 2.

PNG_EQUATION_BASE_E
    PNG_EQUATION_BASE_E has value 1.

PNG_EQUATION_HYPERBOLIC
    PNG_EQUATION_HYPERBOLIC has value 3.

PNG_EQUATION_LINEAR
    PNG_EQUATION_LINEAR has value 0.

PNG_ERROR_ACTION_ERROR
    PNG_ERROR_ACTION_ERROR has value 3.

PNG_ERROR_ACTION_NONE
    PNG_ERROR_ACTION_NONE has value 1.

PNG_ERROR_ACTION_WARN
    PNG_ERROR_ACTION_WARN has value 2.

PNG_FAST_FILTERS
    PNG_FAST_FILTERS has value (0x08 | 0x10 | 0x20).

PNG_FILLER_AFTER
    PNG_FILLER_AFTER has value 1.

PNG_FILLER_BEFORE
    PNG_FILLER_BEFORE has value 0.

PNG_FILTER_AVG
    PNG_FILTER_AVG has value 0x40.

PNG_FILTER_HEURISTIC_DEFAULT
    PNG_FILTER_HEURISTIC_DEFAULT has value 0.

PNG_FILTER_HEURISTIC_UNWEIGHTED
    PNG_FILTER_HEURISTIC_UNWEIGHTED has value 1.

PNG_FILTER_HEURISTIC_WEIGHTED
    PNG_FILTER_HEURISTIC_WEIGHTED has value 2.

PNG_FILTER_NONE
    PNG_FILTER_NONE has value 0x08.

PNG_FILTER_PAETH
    PNG_FILTER_PAETH has value 0x80.

PNG_FILTER_SUB
    PNG_FILTER_SUB has value 0x10.

PNG_FILTER_TYPE_BASE
    PNG_FILTER_TYPE_BASE has value 0.

PNG_FILTER_TYPE_DEFAULT
    PNG_FILTER_TYPE_DEFAULT has value 0.

PNG_FILTER_UP
    PNG_FILTER_UP has value 0x20.

PNG_FILTER_VALUE_AVG
    PNG_FILTER_VALUE_AVG has value 3.

PNG_FILTER_VALUE_NONE
    PNG_FILTER_VALUE_NONE has value 0.

PNG_FILTER_VALUE_PAETH
    PNG_FILTER_VALUE_PAETH has value 4.

PNG_FILTER_VALUE_SUB
    PNG_FILTER_VALUE_SUB has value 1.

PNG_FILTER_VALUE_UP
    PNG_FILTER_VALUE_UP has value 2.

PNG_FLAG_MNG_EMPTY_PLTE
    PNG_FLAG_MNG_EMPTY_PLTE has value 0x01.

PNG_FLAG_MNG_FILTER_64
    PNG_FLAG_MNG_FILTER_64 has value 0x04.

PNG_FORMAT_ABGR
    PNG_FORMAT_ABGR has value (((0x02|0x10)|0x01)|0x20).

PNG_FORMAT_ABGR_COLORMAP
    PNG_FORMAT_ABGR_COLORMAP has value ((((0x02|0x10)|0x01)|0x20)|0x08).

PNG_FORMAT_AG
    PNG_FORMAT_AG has value (0x01|0x20).

PNG_FORMAT_ARGB
    PNG_FORMAT_ARGB has value ((0x02|0x01)|0x20).

PNG_FORMAT_ARGB_COLORMAP
    PNG_FORMAT_ARGB_COLORMAP has value (((0x02|0x01)|0x20)|0x08).

PNG_FORMAT_BGR
    PNG_FORMAT_BGR has value (0x02|0x10).

PNG_FORMAT_BGRA
    PNG_FORMAT_BGRA has value ((0x02|0x10)|0x01).

PNG_FORMAT_BGRA_COLORMAP
    PNG_FORMAT_BGRA_COLORMAP has value (((0x02|0x10)|0x01)|0x08).

PNG_FORMAT_BGR_COLORMAP
    PNG_FORMAT_BGR_COLORMAP has value ((0x02|0x10)|0x08).

PNG_FORMAT_FLAG_AFIRST
    PNG_FORMAT_FLAG_AFIRST has value 0x20.

PNG_FORMAT_FLAG_ALPHA
    PNG_FORMAT_FLAG_ALPHA has value 0x01.

PNG_FORMAT_FLAG_ASSOCIATED_ALPHA
    PNG_FORMAT_FLAG_ASSOCIATED_ALPHA has value 0x40.

PNG_FORMAT_FLAG_BGR
    PNG_FORMAT_FLAG_BGR has value 0x10.

PNG_FORMAT_FLAG_COLOR
    PNG_FORMAT_FLAG_COLOR has value 0x02.

PNG_FORMAT_FLAG_COLORMAP
    PNG_FORMAT_FLAG_COLORMAP has value 0x08.

PNG_FORMAT_FLAG_LINEAR
    PNG_FORMAT_FLAG_LINEAR has value 0x04.

PNG_FORMAT_GA
    PNG_FORMAT_GA has value 0x01.

PNG_FORMAT_GRAY
    PNG_FORMAT_GRAY has value 0.

PNG_FORMAT_LINEAR_RGB
    PNG_FORMAT_LINEAR_RGB has value (0x04|0x02).

PNG_FORMAT_LINEAR_Y
    PNG_FORMAT_LINEAR_Y has value 0x04.

PNG_FORMAT_LINEAR_Y_ALPHA
    PNG_FORMAT_LINEAR_Y_ALPHA has value (0x04|0x01).

PNG_FORMAT_RGB
    PNG_FORMAT_RGB has value 0x02.

PNG_FORMAT_RGBA
    PNG_FORMAT_RGBA has value (0x02|0x01).

PNG_FORMAT_RGBA_COLORMAP
    PNG_FORMAT_RGBA_COLORMAP has value ((0x02|0x01)|0x08).

PNG_FORMAT_RGB_COLORMAP
    PNG_FORMAT_RGB_COLORMAP has value (0x02|0x08).

PNG_FP_1
    PNG_FP_1 has value 100000.

PNG_FP_HALF
    PNG_FP_HALF has value 50000.

PNG_FP_MIN
    PNG_FP_MIN has value (-PNG_FP_MAX).

PNG_FREE_ALL
    PNG_FREE_ALL has value 0xffff.

PNG_FREE_EXIF
    PNG_FREE_EXIF has value 0x8000.

PNG_FREE_HIST
    PNG_FREE_HIST has value 0x0008.

PNG_FREE_ICCP
    PNG_FREE_ICCP has value 0x0010.

PNG_FREE_MUL
    PNG_FREE_MUL has value 0x4220.

PNG_FREE_PCAL
    PNG_FREE_PCAL has value 0x0080.

PNG_FREE_PLTE
    PNG_FREE_PLTE has value 0x1000.

PNG_FREE_ROWS
    PNG_FREE_ROWS has value 0x0040.

PNG_FREE_SCAL
    PNG_FREE_SCAL has value 0x0100.

PNG_FREE_SPLT
    PNG_FREE_SPLT has value 0x0020.

PNG_FREE_TEXT
    PNG_FREE_TEXT has value 0x4000.

PNG_FREE_TRNS
    PNG_FREE_TRNS has value 0x2000.

PNG_FREE_UNKN
    PNG_FREE_UNKN has value 0x0200.

PNG_GAMMA_LINEAR
    PNG_GAMMA_LINEAR has value 100000.

PNG_GAMMA_MAC_18
    PNG_GAMMA_MAC_18 has value -2.

PNG_GAMMA_THRESHOLD
    PNG_GAMMA_THRESHOLD has value (PNG_GAMMA_THRESHOLD_FIXED*.00001).

PNG_GAMMA_sRGB
    PNG_GAMMA_sRGB has value 220000.

PNG_HANDLE_CHUNK_ALWAYS
    PNG_HANDLE_CHUNK_ALWAYS has value 3.

PNG_HANDLE_CHUNK_AS_DEFAULT
    PNG_HANDLE_CHUNK_AS_DEFAULT has value 0.

PNG_HANDLE_CHUNK_IF_SAFE
    PNG_HANDLE_CHUNK_IF_SAFE has value 2.

PNG_HANDLE_CHUNK_NEVER
    PNG_HANDLE_CHUNK_NEVER has value 1.

PNG_HAVE_IHDR
    PNG_HAVE_IHDR has value 0x01.

PNG_HAVE_PLTE
    PNG_HAVE_PLTE has value 0x02.

PNG_IGNORE_ADLER32
    PNG_IGNORE_ADLER32 has value 8.

PNG_IMAGE_ERROR
    PNG_IMAGE_ERROR has value 2.

PNG_IMAGE_FLAG_16BIT_sRGB
    PNG_IMAGE_FLAG_16BIT_sRGB has value 0x04.

PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB
    PNG_IMAGE_FLAG_COLORSPACE_NOT_sRGB has value 0x01.

PNG_IMAGE_FLAG_FAST
    PNG_IMAGE_FLAG_FAST has value 0x02.

PNG_IMAGE_VERSION
    PNG_IMAGE_VERSION has value 1.

PNG_IMAGE_WARNING
    PNG_IMAGE_WARNING has value 1.

PNG_INFO_IDAT
    PNG_INFO_IDAT has value 0x8000.

PNG_INFO_PLTE
    PNG_INFO_PLTE has value 0x0008.

PNG_INFO_acTL
    PNG_INFO_acTL has value 0x100000.

PNG_INFO_bKGD
    PNG_INFO_bKGD has value 0x0020.

PNG_INFO_cHRM
    PNG_INFO_cHRM has value 0x0004.

PNG_INFO_cICP
    PNG_INFO_cICP has value 0x20000.

PNG_INFO_cLLI
    PNG_INFO_cLLI has value 0x40000.

PNG_INFO_eXIf
    PNG_INFO_eXIf has value 0x10000.

PNG_INFO_fcTL
    PNG_INFO_fcTL has value 0x200000.

PNG_INFO_fdAT
    PNG_INFO_fdAT has value 0x400000.

PNG_INFO_gAMA
    PNG_INFO_gAMA has value 0x0001.

PNG_INFO_hIST
    PNG_INFO_hIST has value 0x0040.

PNG_INFO_iCCP
    PNG_INFO_iCCP has value 0x1000.

PNG_INFO_mDCV
    PNG_INFO_mDCV has value 0x80000.

PNG_INFO_oFFs
    PNG_INFO_oFFs has value 0x0100.

PNG_INFO_pCAL
    PNG_INFO_pCAL has value 0x0400.

PNG_INFO_pHYs
    PNG_INFO_pHYs has value 0x0080.

PNG_INFO_sBIT
    PNG_INFO_sBIT has value 0x0002.

PNG_INFO_sCAL
    PNG_INFO_sCAL has value 0x4000.

PNG_INFO_sPLT
    PNG_INFO_sPLT has value 0x2000.

PNG_INFO_sRGB
    PNG_INFO_sRGB has value 0x0800.

PNG_INFO_tIME
    PNG_INFO_tIME has value 0x0200.

PNG_INFO_tRNS
    PNG_INFO_tRNS has value 0x0010.

PNG_INTERLACE_ADAM7
    PNG_INTERLACE_ADAM7 has value 1.

PNG_INTERLACE_ADAM7_PASSES
    PNG_INTERLACE_ADAM7_PASSES has value 7.

PNG_INTERLACE_NONE
    PNG_INTERLACE_NONE has value 0.

PNG_INTRAPIXEL_DIFFERENCING
    PNG_INTRAPIXEL_DIFFERENCING has value 64.

PNG_IO_CHUNK_CRC
    PNG_IO_CHUNK_CRC has value 0x0080.

PNG_IO_CHUNK_DATA
    PNG_IO_CHUNK_DATA has value 0x0040.

PNG_IO_CHUNK_HDR
    PNG_IO_CHUNK_HDR has value 0x0020.

PNG_IO_MASK_LOC
    PNG_IO_MASK_LOC has value 0x00f0.

PNG_IO_MASK_OP
    PNG_IO_MASK_OP has value 0x000f.

PNG_IO_NONE
    PNG_IO_NONE has value 0x0000.

PNG_IO_READING
    PNG_IO_READING has value 0x0001.

PNG_IO_SIGNATURE
    PNG_IO_SIGNATURE has value 0x0010.

PNG_IO_WRITING
    PNG_IO_WRITING has value 0x0002.

PNG_ITXT_COMPRESSION_NONE
    PNG_ITXT_COMPRESSION_NONE has value 1.

PNG_ITXT_COMPRESSION_zTXt
    PNG_ITXT_COMPRESSION_zTXt has value 2.

PNG_KEYWORD_MAX_LENGTH
    PNG_KEYWORD_MAX_LENGTH has value 79.

PNG_MAXIMUM_INFLATE_WINDOW
    PNG_MAXIMUM_INFLATE_WINDOW has value 2.

PNG_MAX_PALETTE_LENGTH
    PNG_MAX_PALETTE_LENGTH has value 256.

PNG_MIPS_MMI
    PNG_MIPS_MMI has value 12.

PNG_MIPS_MSA
    PNG_MIPS_MSA has value 6.

PNG_NO_FILTERS
    PNG_NO_FILTERS has value 0x00.

PNG_OFFSET_MICROMETER
    PNG_OFFSET_MICROMETER has value 1.

PNG_OFFSET_PIXEL
    PNG_OFFSET_PIXEL has value 0.

PNG_OPTION_INVALID
    PNG_OPTION_INVALID has value 1.

PNG_OPTION_NEXT
    PNG_OPTION_NEXT has value 16.

PNG_OPTION_OFF
    PNG_OPTION_OFF has value 2.

PNG_OPTION_ON
    PNG_OPTION_ON has value 3.

PNG_OPTION_UNSET
    PNG_OPTION_UNSET has value 0.

PNG_POWERPC_VSX
    PNG_POWERPC_VSX has value 10.

PNG_RESOLUTION_METER
    PNG_RESOLUTION_METER has value 1.

PNG_RESOLUTION_UNKNOWN
    PNG_RESOLUTION_UNKNOWN has value 0.

PNG_RGB_TO_GRAY_DEFAULT
    PNG_RGB_TO_GRAY_DEFAULT has value (-1).

PNG_RISCV_RVV
    PNG_RISCV_RVV has value 14.

PNG_SCALE_METER
    PNG_SCALE_METER has value 1.

PNG_SCALE_RADIAN
    PNG_SCALE_RADIAN has value 2.

PNG_SCALE_UNKNOWN
    PNG_SCALE_UNKNOWN has value 0.

PNG_SKIP_sRGB_CHECK_PROFILE
    PNG_SKIP_sRGB_CHECK_PROFILE has value 4.

PNG_TEXT_COMPRESSION_NONE
    PNG_TEXT_COMPRESSION_NONE has value -1.

PNG_TEXT_COMPRESSION_NONE_WR
    PNG_TEXT_COMPRESSION_NONE_WR has value -3.

PNG_TEXT_COMPRESSION_zTXt
    PNG_TEXT_COMPRESSION_zTXt has value 0.

PNG_TEXT_COMPRESSION_zTXt_WR
    PNG_TEXT_COMPRESSION_zTXt_WR has value -2.

PNG_TRANSFORM_BGR
    PNG_TRANSFORM_BGR has value 0x0080.

PNG_TRANSFORM_EXPAND
    PNG_TRANSFORM_EXPAND has value 0x0010.

PNG_TRANSFORM_EXPAND_16
    PNG_TRANSFORM_EXPAND_16 has value 0x4000.

PNG_TRANSFORM_GRAY_TO_RGB
    PNG_TRANSFORM_GRAY_TO_RGB has value 0x2000.

PNG_TRANSFORM_IDENTITY
    PNG_TRANSFORM_IDENTITY has value 0x0000.

PNG_TRANSFORM_INVERT_ALPHA
    PNG_TRANSFORM_INVERT_ALPHA has value 0x0400.

PNG_TRANSFORM_INVERT_MONO
    PNG_TRANSFORM_INVERT_MONO has value 0x0020.

PNG_TRANSFORM_PACKING
    PNG_TRANSFORM_PACKING has value 0x0004.

PNG_TRANSFORM_PACKSWAP
    PNG_TRANSFORM_PACKSWAP has value 0x0008.

PNG_TRANSFORM_SCALE_16
    PNG_TRANSFORM_SCALE_16 has value 0x8000.

PNG_TRANSFORM_SHIFT
    PNG_TRANSFORM_SHIFT has value 0x0040.

PNG_TRANSFORM_STRIP_16
    PNG_TRANSFORM_STRIP_16 has value 0x0001.

PNG_TRANSFORM_STRIP_ALPHA
    PNG_TRANSFORM_STRIP_ALPHA has value 0x0002.

PNG_TRANSFORM_STRIP_FILLER
    PNG_TRANSFORM_STRIP_FILLER has value 0x0800.

PNG_TRANSFORM_STRIP_FILLER_AFTER
    PNG_TRANSFORM_STRIP_FILLER_AFTER has value 0x1000.

PNG_TRANSFORM_STRIP_FILLER_BEFORE
    PNG_TRANSFORM_STRIP_FILLER_BEFORE has value 0x0800.

PNG_TRANSFORM_SWAP_ALPHA
    PNG_TRANSFORM_SWAP_ALPHA has value 0x0100.

PNG_TRANSFORM_SWAP_ENDIAN
    PNG_TRANSFORM_SWAP_ENDIAN has value 0x0200.

PNG_sRGB_INTENT_ABSOLUTE
    PNG_sRGB_INTENT_ABSOLUTE has value 3.

PNG_sRGB_INTENT_PERCEPTUAL
    PNG_sRGB_INTENT_PERCEPTUAL has value 0.

PNG_sRGB_INTENT_RELATIVE
    PNG_sRGB_INTENT_RELATIVE has value 1.

PNG_sRGB_INTENT_SATURATION
    PNG_sRGB_INTENT_SATURATION has value 2.

EXPORTS
Nothing is exported by default, but all the symbols in this module can be exported on request. There is one export tag, 'all', which exports all the symbols in this module:

    use Image::PNG::Const ':all';

ABOUT THIS MODULE
This Perl module was generated from the file png.h supplied with version 1.6.45 of libpng.

AUTHOR
Ben Bullock, <benkasminbullock@gmail.com>

COPYRIGHT & LICENCE
This package and associated files are copyright (C) 2011-2026 Ben Bullock.

You can use, copy, modify and redistribute this package and associated files under the Perl Artistic Licence or the GNU General Public Licence.