PNG (Portable Network Graphics) file: Perl parsing library

NOTICE: Many of the documentation comments (or docstrings) in this file were copied from or derived from the Portable Network Graphics (PNG) Specification (Third Edition). Copyright © 1996-2025 World Wide Web Consortium. https://www.w3.org/copyright/software-license-2023/

The full text of the license for the original W3C PNG specification is provided below:

Software and Document license - 2023 version

This work is being provided by the copyright holders under the following license.

License

By obtaining and/or copying this work, you (the licensee) agree that you have read, understood, and will comply with the following terms and conditions.

Permission to copy, modify, and distribute this work, with or without modification, for any purpose and without fee or royalty is hereby granted, provided that you include the following on ALL copies of the work or portions thereof, including modifications:

  • The full text of this NOTICE in a location viewable to users of the redistributed or derivative work.
  • Any pre-existing intellectual property disclaimers, notices, or terms and conditions. If none exist, the W3C software and document short notice should be included.
  • Notice of any changes or modifications, through a copyright statement on the new code or document such as "This software or document includes material copied from or derived from [title and URI of the W3C document]. Copyright © [$year-of-document] World Wide Web Consortium. https://www.w3.org/copyright/software-license-2023/"

Disclaimers

THIS WORK IS PROVIDED "AS IS," AND COPYRIGHT HOLDERS MAKE NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO, WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR THAT THE USE OF THE SOFTWARE OR DOCUMENT WILL NOT INFRINGE ANY THIRD PARTY PATENTS, COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS.

COPYRIGHT HOLDERS WILL NOT BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF ANY USE OF THE SOFTWARE OR DOCUMENT.

The name and trademarks of copyright holders may NOT be used in advertising or publicity pertaining to the work without specific, written prior permission. Title to copyright in this work will at all times remain with copyright holders.

Test files for APNG can be found at the following locations:

File extension

["png", "apng"]

KS implementation details

License: CC0-1.0
Minimal Kaitai Struct required: 0.11

References

This page hosts a formal specification of PNG (Portable Network Graphics) file using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.

Perl source code to parse PNG (Portable Network Graphics) file

Png.pm

Download 

# This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild

use strict;
use warnings;
use IO::KaitaiStruct 0.011_000;
use Exif;
use Icc4;
use Compress::Zlib;
use Encode;

########################################################################
package Png;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

our $BLEND_OP_VALUES_SOURCE = 0;
our $BLEND_OP_VALUES_OVER = 1;

our $COLOR_TYPE_GREYSCALE = 0;
our $COLOR_TYPE_TRUECOLOR = 2;
our $COLOR_TYPE_INDEXED = 3;
our $COLOR_TYPE_GREYSCALE_ALPHA = 4;
our $COLOR_TYPE_TRUECOLOR_ALPHA = 6;

our $COMPRESSION_METHODS_ZLIB = 0;

our $DISPOSE_OP_VALUES_NONE = 0;
our $DISPOSE_OP_VALUES_BACKGROUND = 1;
our $DISPOSE_OP_VALUES_PREVIOUS = 2;

our $FILTER_METHOD_BASE = 0;

our $INTERLACE_METHOD_NONE = 0;
our $INTERLACE_METHOD_ADAM7 = 1;

our $PHYS_UNIT_UNKNOWN = 0;
our $PHYS_UNIT_METER = 1;

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root || $self;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{magic} = $self->{_io}->read_bytes(8);
    $self->{ihdr_len} = $self->{_io}->read_u4be();
    $self->{ihdr_type} = $self->{_io}->read_bytes(4);
    $self->{ihdr} = Png::IhdrChunk->new($self->{_io}, $self, $self->{_root});
    $self->{ihdr_crc} = $self->{_io}->read_u4be();
    $self->{chunks} = [];
    {
        my $_it;
        do {
            $_it = Png::Chunk->new($self->{_io}, $self, $self->{_root});
            push @{$self->{chunks}}, $_it;
        } until ( (($_it->type() eq "IEND") || ($self->_io()->is_eof())) );
    }
}

sub magic {
    my ($self) = @_;
    return $self->{magic};
}

sub ihdr_len {
    my ($self) = @_;
    return $self->{ihdr_len};
}

sub ihdr_type {
    my ($self) = @_;
    return $self->{ihdr_type};
}

sub ihdr {
    my ($self) = @_;
    return $self->{ihdr};
}

sub ihdr_crc {
    my ($self) = @_;
    return $self->{ihdr_crc};
}

sub chunks {
    my ($self) = @_;
    return $self->{chunks};
}

########################################################################
package Png::AdobeFireworksChunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{_raw_preview_data} = $self->{_io}->read_bytes_full();
    $self->{preview_data} = Compress::Zlib::uncompress($self->{_raw_preview_data});
}

sub preview_data {
    my ($self) = @_;
    return $self->{preview_data};
}

sub _raw_preview_data {
    my ($self) = @_;
    return $self->{_raw_preview_data};
}

########################################################################
package Png::AnimationControlChunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{num_frames} = $self->{_io}->read_u4be();
    $self->{num_plays} = $self->{_io}->read_u4be();
}

sub num_frames {
    my ($self) = @_;
    return $self->{num_frames};
}

sub num_plays {
    my ($self) = @_;
    return $self->{num_plays};
}

########################################################################
package Png::AtchChunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

our $COMPRESSION_ATTACH_METHODS_NONE = 0;
our $COMPRESSION_ATTACH_METHODS_ZLIB = 1;

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{file_name} = Encode::decode("UTF-8", $self->{_io}->read_bytes_term(0, 0, 1, 1));
    {
        my $_it = $self->{file_name};
    }
    $self->{compression} = $self->{_io}->read_u1();
    if ($self->compression() == $Png::AtchChunk::COMPRESSION_ATTACH_METHODS_NONE) {
        $self->{data_plain} = $self->{_io}->read_bytes_full();
    }
    if ($self->compression() == $Png::AtchChunk::COMPRESSION_ATTACH_METHODS_ZLIB) {
        $self->{_raw_data_zlib} = $self->{_io}->read_bytes_full();
        $self->{data_zlib} = Compress::Zlib::uncompress($self->{_raw_data_zlib});
    }
}

sub data {
    my ($self) = @_;
    return $self->{data} if ($self->{data});
    $self->{data} = ($self->compression() == $Png::AtchChunk::COMPRESSION_ATTACH_METHODS_NONE ? $self->data_plain() : $self->data_zlib());
    return $self->{data};
}

sub file_name {
    my ($self) = @_;
    return $self->{file_name};
}

sub compression {
    my ($self) = @_;
    return $self->{compression};
}

sub data_plain {
    my ($self) = @_;
    return $self->{data_plain};
}

sub data_zlib {
    my ($self) = @_;
    return $self->{data_zlib};
}

sub _raw_data_zlib {
    my ($self) = @_;
    return $self->{_raw_data_zlib};
}

########################################################################
package Png::BkgdChunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    my $_on = $self->_root()->ihdr()->color_type();
    if ($_on == $Png::COLOR_TYPE_GREYSCALE) {
        $self->{bkgd} = Png::BkgdGreyscale->new($self->{_io}, $self, $self->{_root});
    }
    elsif ($_on == $Png::COLOR_TYPE_GREYSCALE_ALPHA) {
        $self->{bkgd} = Png::BkgdGreyscale->new($self->{_io}, $self, $self->{_root});
    }
    elsif ($_on == $Png::COLOR_TYPE_INDEXED) {
        $self->{bkgd} = Png::BkgdIndexed->new($self->{_io}, $self, $self->{_root});
    }
    elsif ($_on == $Png::COLOR_TYPE_TRUECOLOR) {
        $self->{bkgd} = Png::BkgdTruecolor->new($self->{_io}, $self, $self->{_root});
    }
    elsif ($_on == $Png::COLOR_TYPE_TRUECOLOR_ALPHA) {
        $self->{bkgd} = Png::BkgdTruecolor->new($self->{_io}, $self, $self->{_root});
    }
}

sub bkgd {
    my ($self) = @_;
    return $self->{bkgd};
}

########################################################################
package Png::BkgdGreyscale;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{value} = $self->{_io}->read_u2be();
}

sub value {
    my ($self) = @_;
    return $self->{value};
}

########################################################################
package Png::BkgdIndexed;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{palette_index} = $self->{_io}->read_u1();
}

sub palette_index {
    my ($self) = @_;
    return $self->{palette_index};
}

########################################################################
package Png::BkgdTruecolor;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{red} = $self->{_io}->read_u2be();
    $self->{green} = $self->{_io}->read_u2be();
    $self->{blue} = $self->{_io}->read_u2be();
}

sub red {
    my ($self) = @_;
    return $self->{red};
}

sub green {
    my ($self) = @_;
    return $self->{green};
}

sub blue {
    my ($self) = @_;
    return $self->{blue};
}

########################################################################
package Png::ChrmChromaticity;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{x_int} = $self->{_io}->read_u4be();
    $self->{y_int} = $self->{_io}->read_u4be();
}

sub x {
    my ($self) = @_;
    return $self->{x} if ($self->{x});
    $self->{x} = $self->x_int() / 100000.0;
    return $self->{x};
}

sub y {
    my ($self) = @_;
    return $self->{y} if ($self->{y});
    $self->{y} = $self->y_int() / 100000.0;
    return $self->{y};
}

sub x_int {
    my ($self) = @_;
    return $self->{x_int};
}

sub y_int {
    my ($self) = @_;
    return $self->{y_int};
}

########################################################################
package Png::ChrmChunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{white_point} = Png::ChrmChromaticity->new($self->{_io}, $self, $self->{_root});
    $self->{red} = Png::ChrmChromaticity->new($self->{_io}, $self, $self->{_root});
    $self->{green} = Png::ChrmChromaticity->new($self->{_io}, $self, $self->{_root});
    $self->{blue} = Png::ChrmChromaticity->new($self->{_io}, $self, $self->{_root});
}

sub white_point {
    my ($self) = @_;
    return $self->{white_point};
}

sub red {
    my ($self) = @_;
    return $self->{red};
}

sub green {
    my ($self) = @_;
    return $self->{green};
}

sub blue {
    my ($self) = @_;
    return $self->{blue};
}

########################################################################
package Png::Chunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{len} = $self->{_io}->read_u4be();
    $self->{type_raw} = $self->{_io}->read_bytes(4);
    {
        my $_it = $self->{type_raw};
    }
    my $_on = $self->type();
    if ($_on eq "PLTE") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::PlteChunk->new($io__raw_body, $self, $self->{_root});
    }
    elsif ($_on eq "acTL") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::AnimationControlChunk->new($io__raw_body, $self, $self->{_root});
    }
    elsif ($_on eq "atCh") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::AtchChunk->new($io__raw_body, $self, $self->{_root});
    }
    elsif ($_on eq "bKGD") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::BkgdChunk->new($io__raw_body, $self, $self->{_root});
    }
    elsif ($_on eq "cHRM") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::ChrmChunk->new($io__raw_body, $self, $self->{_root});
    }
    elsif ($_on eq "cICP") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::CicpChunk->new($io__raw_body, $self, $self->{_root});
    }
    elsif ($_on eq "cLLI") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::ClliChunk->new($io__raw_body, $self, $self->{_root});
    }
    elsif ($_on eq "eXIf") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::ExifChunk->new($io__raw_body, $self, $self->{_root});
    }
    elsif ($_on eq "fcTL") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::FrameControlChunk->new($io__raw_body, $self, $self->{_root});
    }
    elsif ($_on eq "fdAT") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::FrameDataChunk->new($io__raw_body, $self, $self->{_root});
    }
    elsif ($_on eq "gAMA") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::GamaChunk->new($io__raw_body, $self, $self->{_root});
    }
    elsif ($_on eq "hIST") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::HistChunk->new($io__raw_body, $self, $self->{_root});
    }
    elsif ($_on eq "iCCP") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::IccpChunk->new($io__raw_body, $self, $self->{_root});
    }
    elsif ($_on eq "iTXt") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::InternationalTextChunk->new($io__raw_body, $self, $self->{_root});
    }
    elsif ($_on eq "mDCV") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::MdcvChunk->new($io__raw_body, $self, $self->{_root});
    }
    elsif ($_on eq "mkBS") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::AdobeFireworksChunk->new($io__raw_body, $self, $self->{_root});
    }
    elsif ($_on eq "mkTS") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::AdobeFireworksChunk->new($io__raw_body, $self, $self->{_root});
    }
    elsif ($_on eq "pHYs") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::PhysChunk->new($io__raw_body, $self, $self->{_root});
    }
    elsif ($_on eq "prVW") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::AdobeFireworksChunk->new($io__raw_body, $self, $self->{_root});
    }
    elsif ($_on eq "sBIT") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::SbitChunk->new($io__raw_body, $self, $self->{_root});
    }
    elsif ($_on eq "sPLT") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::SpltChunk->new($io__raw_body, $self, $self->{_root});
    }
    elsif ($_on eq "sRGB") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::SrgbChunk->new($io__raw_body, $self, $self->{_root});
    }
    elsif ($_on eq "skMf") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::EvernoteSkmfChunk->new($io__raw_body, $self, $self->{_root});
    }
    elsif ($_on eq "skRf") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::EvernoteSkrfChunk->new($io__raw_body, $self, $self->{_root});
    }
    elsif ($_on eq "tEXt") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::TextChunk->new($io__raw_body, $self, $self->{_root});
    }
    elsif ($_on eq "tIME") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::TimeChunk->new($io__raw_body, $self, $self->{_root});
    }
    elsif ($_on eq "tRNS") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::TrnsChunk->new($io__raw_body, $self, $self->{_root});
    }
    elsif ($_on eq "zTXt") {
        $self->{_raw_body} = $self->{_io}->read_bytes($self->len());
        my $io__raw_body = IO::KaitaiStruct::Stream->new($self->{_raw_body});
        $self->{body} = Png::CompressedTextChunk->new($io__raw_body, $self, $self->{_root});
    }
    else {
        $self->{body} = $self->{_io}->read_bytes($self->len());
    }
    $self->{crc} = $self->{_io}->read_u4be();
}

sub is_ancillary {
    my ($self) = @_;
    return $self->{is_ancillary} if ($self->{is_ancillary});
    $self->{is_ancillary} = (unpack('C', substr($self->type_raw(), 0, 1)) & 32) != 0;
    return $self->{is_ancillary};
}

sub is_private {
    my ($self) = @_;
    return $self->{is_private} if ($self->{is_private});
    $self->{is_private} = (unpack('C', substr($self->type_raw(), 1, 1)) & 32) != 0;
    return $self->{is_private};
}

sub is_safe_to_copy {
    my ($self) = @_;
    return $self->{is_safe_to_copy} if ($self->{is_safe_to_copy});
    $self->{is_safe_to_copy} = (unpack('C', substr($self->type_raw(), 3, 1)) & 32) != 0;
    return $self->{is_safe_to_copy};
}

sub reserved_bit {
    my ($self) = @_;
    return $self->{reserved_bit} if ($self->{reserved_bit});
    $self->{reserved_bit} = (unpack('C', substr($self->type_raw(), 2, 1)) & 32) != 0;
    return $self->{reserved_bit};
}

sub type {
    my ($self) = @_;
    return $self->{type} if ($self->{type});
    $self->{type} = Encode::decode("ASCII", $self->type_raw());
    return $self->{type};
}

sub len {
    my ($self) = @_;
    return $self->{len};
}

sub type_raw {
    my ($self) = @_;
    return $self->{type_raw};
}

sub body {
    my ($self) = @_;
    return $self->{body};
}

sub crc {
    my ($self) = @_;
    return $self->{crc};
}

sub _raw_body {
    my ($self) = @_;
    return $self->{_raw_body};
}

########################################################################
package Png::CicpChunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{color_primaries} = $self->{_io}->read_u1();
    $self->{transfer_function} = $self->{_io}->read_u1();
    $self->{matrix_coefficients} = $self->{_io}->read_u1();
    $self->{video_full_range_flag} = $self->{_io}->read_u1();
}

sub color_primaries {
    my ($self) = @_;
    return $self->{color_primaries};
}

sub transfer_function {
    my ($self) = @_;
    return $self->{transfer_function};
}

sub matrix_coefficients {
    my ($self) = @_;
    return $self->{matrix_coefficients};
}

sub video_full_range_flag {
    my ($self) = @_;
    return $self->{video_full_range_flag};
}

########################################################################
package Png::ClliChunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{max_content_light_level_int} = $self->{_io}->read_u4be();
    $self->{max_frame_average_light_level_int} = $self->{_io}->read_u4be();
}

sub max_content_light_level {
    my ($self) = @_;
    return $self->{max_content_light_level} if ($self->{max_content_light_level});
    $self->{max_content_light_level} = $self->max_content_light_level_int() * 0.0001;
    return $self->{max_content_light_level};
}

sub max_frame_average_light_level {
    my ($self) = @_;
    return $self->{max_frame_average_light_level} if ($self->{max_frame_average_light_level});
    $self->{max_frame_average_light_level} = $self->max_frame_average_light_level_int() * 0.0001;
    return $self->{max_frame_average_light_level};
}

sub max_content_light_level_int {
    my ($self) = @_;
    return $self->{max_content_light_level_int};
}

sub max_frame_average_light_level_int {
    my ($self) = @_;
    return $self->{max_frame_average_light_level_int};
}

########################################################################
package Png::CompressedText;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{value} = Encode::decode("ISO-8859-1", $self->{_io}->read_bytes_full());
}

sub value {
    my ($self) = @_;
    return $self->{value};
}

########################################################################
package Png::CompressedTextChunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{keyword} = Encode::decode("ISO-8859-1", $self->{_io}->read_bytes_term(0, 0, 1, 1));
    $self->{compression_method} = $self->{_io}->read_u1();
    $self->{_raw__raw_text} = $self->{_io}->read_bytes_full();
    $self->{_raw_text} = Compress::Zlib::uncompress($self->{_raw__raw_text});
    my $io__raw_text = IO::KaitaiStruct::Stream->new($self->{_raw_text});
    $self->{text} = Png::CompressedText->new($io__raw_text, $self, $self->{_root});
}

sub keyword {
    my ($self) = @_;
    return $self->{keyword};
}

sub compression_method {
    my ($self) = @_;
    return $self->{compression_method};
}

sub text {
    my ($self) = @_;
    return $self->{text};
}

sub _raw_text {
    my ($self) = @_;
    return $self->{_raw_text};
}

sub _raw__raw_text {
    my ($self) = @_;
    return $self->{_raw__raw_text};
}

########################################################################
package Png::EvernoteSkmfChunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{json} = Encode::decode("UTF-8", $self->{_io}->read_bytes_full());
}

sub json {
    my ($self) = @_;
    return $self->{json};
}

########################################################################
package Png::EvernoteSkrfChunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{uuid} = $self->{_io}->read_bytes(16);
    $self->{orig_img} = $self->{_io}->read_bytes_full();
}

sub uuid {
    my ($self) = @_;
    return $self->{uuid};
}

sub orig_img {
    my ($self) = @_;
    return $self->{orig_img};
}

########################################################################
package Png::ExifChunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{exif} = Exif->new($self->{_io});
}

sub exif {
    my ($self) = @_;
    return $self->{exif};
}

########################################################################
package Png::FrameControlChunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{sequence_number} = $self->{_io}->read_u4be();
    $self->{width} = $self->{_io}->read_u4be();
    $self->{height} = $self->{_io}->read_u4be();
    $self->{x_offset} = $self->{_io}->read_u4be();
    $self->{y_offset} = $self->{_io}->read_u4be();
    $self->{delay_num} = $self->{_io}->read_u2be();
    $self->{delay_den} = $self->{_io}->read_u2be();
    $self->{dispose_op} = $self->{_io}->read_u1();
    $self->{blend_op} = $self->{_io}->read_u1();
}

sub delay {
    my ($self) = @_;
    return $self->{delay} if ($self->{delay});
    $self->{delay} = $self->delay_num() / ($self->delay_den() == 0 ? 100.0 : $self->delay_den());
    return $self->{delay};
}

sub sequence_number {
    my ($self) = @_;
    return $self->{sequence_number};
}

sub width {
    my ($self) = @_;
    return $self->{width};
}

sub height {
    my ($self) = @_;
    return $self->{height};
}

sub x_offset {
    my ($self) = @_;
    return $self->{x_offset};
}

sub y_offset {
    my ($self) = @_;
    return $self->{y_offset};
}

sub delay_num {
    my ($self) = @_;
    return $self->{delay_num};
}

sub delay_den {
    my ($self) = @_;
    return $self->{delay_den};
}

sub dispose_op {
    my ($self) = @_;
    return $self->{dispose_op};
}

sub blend_op {
    my ($self) = @_;
    return $self->{blend_op};
}

########################################################################
package Png::FrameDataChunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{sequence_number} = $self->{_io}->read_u4be();
    $self->{frame_data} = $self->{_io}->read_bytes_full();
}

sub sequence_number {
    my ($self) = @_;
    return $self->{sequence_number};
}

sub frame_data {
    my ($self) = @_;
    return $self->{frame_data};
}

########################################################################
package Png::GamaChunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{gamma_int} = $self->{_io}->read_u4be();
    {
        my $_it = $self->{gamma_int};
    }
}

sub gamma {
    my ($self) = @_;
    return $self->{gamma} if ($self->{gamma});
    $self->{gamma} = $self->gamma_int() / 100000.0;
    return $self->{gamma};
}

sub inv_gamma {
    my ($self) = @_;
    return $self->{inv_gamma} if ($self->{inv_gamma});
    $self->{inv_gamma} = 100000.0 / $self->gamma_int();
    return $self->{inv_gamma};
}

sub gamma_int {
    my ($self) = @_;
    return $self->{gamma_int};
}

########################################################################
package Png::HistChunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{usage_freqs} = [];
    while (!$self->{_io}->is_eof()) {
        push @{$self->{usage_freqs}}, $self->{_io}->read_u2be();
    }
}

sub usage_freqs {
    my ($self) = @_;
    return $self->{usage_freqs};
}

########################################################################
package Png::IccpChunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{profile_name} = Encode::decode("ISO-8859-1", $self->{_io}->read_bytes_term(0, 0, 1, 1));
    $self->{compression_method} = $self->{_io}->read_u1();
    $self->{_raw__raw_profile} = $self->{_io}->read_bytes_full();
    $self->{_raw_profile} = Compress::Zlib::uncompress($self->{_raw__raw_profile});
    my $io__raw_profile = IO::KaitaiStruct::Stream->new($self->{_raw_profile});
    $self->{profile} = Icc4->new($io__raw_profile);
}

sub profile_name {
    my ($self) = @_;
    return $self->{profile_name};
}

sub compression_method {
    my ($self) = @_;
    return $self->{compression_method};
}

sub profile {
    my ($self) = @_;
    return $self->{profile};
}

sub _raw_profile {
    my ($self) = @_;
    return $self->{_raw_profile};
}

sub _raw__raw_profile {
    my ($self) = @_;
    return $self->{_raw__raw_profile};
}

########################################################################
package Png::IhdrChunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{width} = $self->{_io}->read_u4be();
    $self->{height} = $self->{_io}->read_u4be();
    $self->{bit_depth} = $self->{_io}->read_u1();
    $self->{color_type} = $self->{_io}->read_u1();
    $self->{compression_method} = $self->{_io}->read_u1();
    $self->{filter_method} = $self->{_io}->read_u1();
    $self->{interlace_method} = $self->{_io}->read_u1();
}

sub width {
    my ($self) = @_;
    return $self->{width};
}

sub height {
    my ($self) = @_;
    return $self->{height};
}

sub bit_depth {
    my ($self) = @_;
    return $self->{bit_depth};
}

sub color_type {
    my ($self) = @_;
    return $self->{color_type};
}

sub compression_method {
    my ($self) = @_;
    return $self->{compression_method};
}

sub filter_method {
    my ($self) = @_;
    return $self->{filter_method};
}

sub interlace_method {
    my ($self) = @_;
    return $self->{interlace_method};
}

########################################################################
package Png::InternationalText;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{value} = Encode::decode("UTF-8", $self->{_io}->read_bytes_full());
}

sub value {
    my ($self) = @_;
    return $self->{value};
}

########################################################################
package Png::InternationalTextChunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{keyword} = Encode::decode("ISO-8859-1", $self->{_io}->read_bytes_term(0, 0, 1, 1));
    $self->{compression_flag} = $self->{_io}->read_u1();
    $self->{compression_method} = $self->{_io}->read_u1();
    $self->{language_tag} = Encode::decode("ASCII", $self->{_io}->read_bytes_term(0, 0, 1, 1));
    $self->{translated_keyword} = Encode::decode("UTF-8", $self->{_io}->read_bytes_term(0, 0, 1, 1));
    if ($self->compression_flag() == 0) {
        $self->{_raw_text_plain} = $self->{_io}->read_bytes_full();
        my $io__raw_text_plain = IO::KaitaiStruct::Stream->new($self->{_raw_text_plain});
        $self->{text_plain} = Png::InternationalText->new($io__raw_text_plain, $self, $self->{_root});
    }
    if ($self->compression_flag() == 1) {
        $self->{_raw__raw_text_zlib} = $self->{_io}->read_bytes_full();
        $self->{_raw_text_zlib} = Compress::Zlib::uncompress($self->{_raw__raw_text_zlib});
        my $io__raw_text_zlib = IO::KaitaiStruct::Stream->new($self->{_raw_text_zlib});
        $self->{text_zlib} = Png::InternationalText->new($io__raw_text_zlib, $self, $self->{_root});
    }
}

sub text {
    my ($self) = @_;
    return $self->{text} if ($self->{text});
    $self->{text} = ($self->compression_flag() == 0 ? $self->text_plain() : $self->text_zlib())->value();
    return $self->{text};
}

sub keyword {
    my ($self) = @_;
    return $self->{keyword};
}

sub compression_flag {
    my ($self) = @_;
    return $self->{compression_flag};
}

sub compression_method {
    my ($self) = @_;
    return $self->{compression_method};
}

sub language_tag {
    my ($self) = @_;
    return $self->{language_tag};
}

sub translated_keyword {
    my ($self) = @_;
    return $self->{translated_keyword};
}

sub text_plain {
    my ($self) = @_;
    return $self->{text_plain};
}

sub text_zlib {
    my ($self) = @_;
    return $self->{text_zlib};
}

sub _raw_text_plain {
    my ($self) = @_;
    return $self->{_raw_text_plain};
}

sub _raw_text_zlib {
    my ($self) = @_;
    return $self->{_raw_text_zlib};
}

sub _raw__raw_text_zlib {
    my ($self) = @_;
    return $self->{_raw__raw_text_zlib};
}

########################################################################
package Png::MdcvChromaticity;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{x_int} = $self->{_io}->read_u2be();
    $self->{y_int} = $self->{_io}->read_u2be();
}

sub x {
    my ($self) = @_;
    return $self->{x} if ($self->{x});
    $self->{x} = $self->x_int() * 0.00002;
    return $self->{x};
}

sub y {
    my ($self) = @_;
    return $self->{y} if ($self->{y});
    $self->{y} = $self->y_int() * 0.00002;
    return $self->{y};
}

sub x_int {
    my ($self) = @_;
    return $self->{x_int};
}

sub y_int {
    my ($self) = @_;
    return $self->{y_int};
}

########################################################################
package Png::MdcvChunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{red} = Png::MdcvChromaticity->new($self->{_io}, $self, $self->{_root});
    $self->{green} = Png::MdcvChromaticity->new($self->{_io}, $self, $self->{_root});
    $self->{blue} = Png::MdcvChromaticity->new($self->{_io}, $self, $self->{_root});
    $self->{white_point} = Png::MdcvChromaticity->new($self->{_io}, $self, $self->{_root});
    $self->{max_luminance_int} = $self->{_io}->read_u4be();
    $self->{min_luminance_int} = $self->{_io}->read_u4be();
}

sub max_luminance {
    my ($self) = @_;
    return $self->{max_luminance} if ($self->{max_luminance});
    $self->{max_luminance} = $self->max_luminance_int() * 0.0001;
    return $self->{max_luminance};
}

sub min_luminance {
    my ($self) = @_;
    return $self->{min_luminance} if ($self->{min_luminance});
    $self->{min_luminance} = $self->min_luminance_int() * 0.0001;
    return $self->{min_luminance};
}

sub red {
    my ($self) = @_;
    return $self->{red};
}

sub green {
    my ($self) = @_;
    return $self->{green};
}

sub blue {
    my ($self) = @_;
    return $self->{blue};
}

sub white_point {
    my ($self) = @_;
    return $self->{white_point};
}

sub max_luminance_int {
    my ($self) = @_;
    return $self->{max_luminance_int};
}

sub min_luminance_int {
    my ($self) = @_;
    return $self->{min_luminance_int};
}

########################################################################
package Png::PhysChunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{pixels_per_unit_x} = $self->{_io}->read_u4be();
    $self->{pixels_per_unit_y} = $self->{_io}->read_u4be();
    $self->{unit} = $self->{_io}->read_u1();
}

sub dots_per_inch_x {
    my ($self) = @_;
    return $self->{dots_per_inch_x} if ($self->{dots_per_inch_x});
    if ($self->unit() == $Png::PHYS_UNIT_METER) {
        $self->{dots_per_inch_x} = $self->pixels_per_unit_x() * 0.0254;
    }
    return $self->{dots_per_inch_x};
}

sub dots_per_inch_y {
    my ($self) = @_;
    return $self->{dots_per_inch_y} if ($self->{dots_per_inch_y});
    if ($self->unit() == $Png::PHYS_UNIT_METER) {
        $self->{dots_per_inch_y} = $self->pixels_per_unit_y() * 0.0254;
    }
    return $self->{dots_per_inch_y};
}

sub pixels_per_unit_x {
    my ($self) = @_;
    return $self->{pixels_per_unit_x};
}

sub pixels_per_unit_y {
    my ($self) = @_;
    return $self->{pixels_per_unit_y};
}

sub unit {
    my ($self) = @_;
    return $self->{unit};
}

########################################################################
package Png::PlteChunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{entries} = [];
    while (!$self->{_io}->is_eof()) {
        push @{$self->{entries}}, Png::Rgb->new($self->{_io}, $self, $self->{_root});
    }
}

sub entries {
    my ($self) = @_;
    return $self->{entries};
}

########################################################################
package Png::Rgb;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{r} = $self->{_io}->read_u1();
    $self->{g} = $self->{_io}->read_u1();
    $self->{b} = $self->{_io}->read_u1();
}

sub r {
    my ($self) = @_;
    return $self->{r};
}

sub g {
    my ($self) = @_;
    return $self->{g};
}

sub b {
    my ($self) = @_;
    return $self->{b};
}

########################################################################
package Png::SbitChunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    my $_on = $self->_root()->ihdr()->color_type();
    if ($_on == $Png::COLOR_TYPE_GREYSCALE) {
        $self->{significant_bits} = Png::SbitGreyscale->new($self->{_io}, $self, $self->{_root});
    }
    elsif ($_on == $Png::COLOR_TYPE_GREYSCALE_ALPHA) {
        $self->{significant_bits} = Png::SbitGreyscale->new($self->{_io}, $self, $self->{_root});
    }
    elsif ($_on == $Png::COLOR_TYPE_INDEXED) {
        $self->{significant_bits} = Png::SbitTruecolor->new($self->{_io}, $self, $self->{_root});
    }
    elsif ($_on == $Png::COLOR_TYPE_TRUECOLOR) {
        $self->{significant_bits} = Png::SbitTruecolor->new($self->{_io}, $self, $self->{_root});
    }
    elsif ($_on == $Png::COLOR_TYPE_TRUECOLOR_ALPHA) {
        $self->{significant_bits} = Png::SbitTruecolor->new($self->{_io}, $self, $self->{_root});
    }
}

sub sample_depth {
    my ($self) = @_;
    return $self->{sample_depth} if ($self->{sample_depth});
    $self->{sample_depth} = ($self->_root()->ihdr()->color_type() == $Png::COLOR_TYPE_INDEXED ? 8 : $self->_root()->ihdr()->bit_depth());
    return $self->{sample_depth};
}

sub significant_bits {
    my ($self) = @_;
    return $self->{significant_bits};
}

########################################################################
package Png::SbitGreyscale;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{grey} = $self->{_io}->read_u1();
    if ($self->has_alpha()) {
        $self->{alpha} = $self->{_io}->read_u1();
    }
}

sub grey {
    my ($self) = @_;
    return $self->{grey};
}

sub alpha {
    my ($self) = @_;
    return $self->{alpha};
}

sub has_alpha {
    my ($self) = @_;
    return $self->{has_alpha};
}

########################################################################
package Png::SbitTruecolor;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{red} = $self->{_io}->read_u1();
    $self->{green} = $self->{_io}->read_u1();
    $self->{blue} = $self->{_io}->read_u1();
    if ($self->has_alpha()) {
        $self->{alpha} = $self->{_io}->read_u1();
    }
}

sub red {
    my ($self) = @_;
    return $self->{red};
}

sub green {
    my ($self) = @_;
    return $self->{green};
}

sub blue {
    my ($self) = @_;
    return $self->{blue};
}

sub alpha {
    my ($self) = @_;
    return $self->{alpha};
}

sub has_alpha {
    my ($self) = @_;
    return $self->{has_alpha};
}

########################################################################
package Png::SpltChunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{palette_name} = Encode::decode("ISO-8859-1", $self->{_io}->read_bytes_term(0, 0, 1, 1));
    $self->{sample_depth} = $self->{_io}->read_u1();
    $self->{entries} = [];
    while (!$self->{_io}->is_eof()) {
        push @{$self->{entries}}, Png::SpltEntry->new($self->{_io}, $self, $self->{_root});
    }
}

sub palette_name {
    my ($self) = @_;
    return $self->{palette_name};
}

sub sample_depth {
    my ($self) = @_;
    return $self->{sample_depth};
}

sub entries {
    my ($self) = @_;
    return $self->{entries};
}

########################################################################
package Png::SpltEntry;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    my $_on = $self->_parent()->sample_depth();
    if ($_on == 8) {
        $self->{red} = $self->{_io}->read_u1();
    }
    else {
        $self->{red} = $self->{_io}->read_u2be();
    }
    my $_on = $self->_parent()->sample_depth();
    if ($_on == 8) {
        $self->{green} = $self->{_io}->read_u1();
    }
    else {
        $self->{green} = $self->{_io}->read_u2be();
    }
    my $_on = $self->_parent()->sample_depth();
    if ($_on == 8) {
        $self->{blue} = $self->{_io}->read_u1();
    }
    else {
        $self->{blue} = $self->{_io}->read_u2be();
    }
    my $_on = $self->_parent()->sample_depth();
    if ($_on == 8) {
        $self->{alpha} = $self->{_io}->read_u1();
    }
    else {
        $self->{alpha} = $self->{_io}->read_u2be();
    }
    $self->{freq} = $self->{_io}->read_u2be();
}

sub red {
    my ($self) = @_;
    return $self->{red};
}

sub green {
    my ($self) = @_;
    return $self->{green};
}

sub blue {
    my ($self) = @_;
    return $self->{blue};
}

sub alpha {
    my ($self) = @_;
    return $self->{alpha};
}

sub freq {
    my ($self) = @_;
    return $self->{freq};
}

########################################################################
package Png::SrgbChunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

our $INTENT_PERCEPTUAL = 0;
our $INTENT_RELATIVE_COLORIMETRIC = 1;
our $INTENT_SATURATION = 2;
our $INTENT_ABSOLUTE_COLORIMETRIC = 3;

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{render_intent} = $self->{_io}->read_u1();
}

sub render_intent {
    my ($self) = @_;
    return $self->{render_intent};
}

########################################################################
package Png::TextChunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{keyword} = Encode::decode("ISO-8859-1", $self->{_io}->read_bytes_term(0, 0, 1, 1));
    $self->{text} = Encode::decode("ISO-8859-1", $self->{_io}->read_bytes_full());
}

sub keyword {
    my ($self) = @_;
    return $self->{keyword};
}

sub text {
    my ($self) = @_;
    return $self->{text};
}

########################################################################
package Png::TimeChunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{year} = $self->{_io}->read_u2be();
    $self->{month} = $self->{_io}->read_u1();
    $self->{day} = $self->{_io}->read_u1();
    $self->{hour} = $self->{_io}->read_u1();
    $self->{minute} = $self->{_io}->read_u1();
    $self->{second} = $self->{_io}->read_u1();
}

sub year {
    my ($self) = @_;
    return $self->{year};
}

sub month {
    my ($self) = @_;
    return $self->{month};
}

sub day {
    my ($self) = @_;
    return $self->{day};
}

sub hour {
    my ($self) = @_;
    return $self->{hour};
}

sub minute {
    my ($self) = @_;
    return $self->{minute};
}

sub second {
    my ($self) = @_;
    return $self->{second};
}

########################################################################
package Png::TrnsChunk;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    if ($self->_root()->ihdr()->color_type() == $Png::COLOR_TYPE_INDEXED) {
        $self->{palette_alphas} = [];
        while (!$self->{_io}->is_eof()) {
            push @{$self->{palette_alphas}}, $self->{_io}->read_u1();
        }
    }
    my $_on = $self->_root()->ihdr()->color_type();
    if ($_on == $Png::COLOR_TYPE_GREYSCALE) {
        $self->{transparent_color} = Png::TrnsGreyscaleColor->new($self->{_io}, $self, $self->{_root});
    }
    elsif ($_on == $Png::COLOR_TYPE_TRUECOLOR) {
        $self->{transparent_color} = Png::TrnsTruecolorColor->new($self->{_io}, $self, $self->{_root});
    }
}

sub sample_mask {
    my ($self) = @_;
    return $self->{sample_mask} if ($self->{sample_mask});
    $self->{sample_mask} = (1 << $self->_root()->ihdr()->bit_depth()) - 1;
    return $self->{sample_mask};
}

sub palette_alphas {
    my ($self) = @_;
    return $self->{palette_alphas};
}

sub transparent_color {
    my ($self) = @_;
    return $self->{transparent_color};
}

########################################################################
package Png::TrnsGreyscaleColor;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{grey_raw} = $self->{_io}->read_u2be();
}

sub grey {
    my ($self) = @_;
    return $self->{grey} if ($self->{grey});
    $self->{grey} = $self->grey_raw() & $self->_parent()->sample_mask();
    return $self->{grey};
}

sub grey_raw {
    my ($self) = @_;
    return $self->{grey_raw};
}

########################################################################
package Png::TrnsTruecolorColor;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{red_raw} = $self->{_io}->read_u2be();
    $self->{green_raw} = $self->{_io}->read_u2be();
    $self->{blue_raw} = $self->{_io}->read_u2be();
}

sub blue {
    my ($self) = @_;
    return $self->{blue} if ($self->{blue});
    $self->{blue} = $self->blue_raw() & $self->_parent()->sample_mask();
    return $self->{blue};
}

sub green {
    my ($self) = @_;
    return $self->{green} if ($self->{green});
    $self->{green} = $self->green_raw() & $self->_parent()->sample_mask();
    return $self->{green};
}

sub red {
    my ($self) = @_;
    return $self->{red} if ($self->{red});
    $self->{red} = $self->red_raw() & $self->_parent()->sample_mask();
    return $self->{red};
}

sub red_raw {
    my ($self) = @_;
    return $self->{red_raw};
}

sub green_raw {
    my ($self) = @_;
    return $self->{green_raw};
}

sub blue_raw {
    my ($self) = @_;
    return $self->{blue_raw};
}

1;