144 lines
4.0 KiB
Perl
144 lines
4.0 KiB
Perl
#------------------------------------------------------------------------------
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# File: PGF.pm
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#
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# Description: Read Progressive Graphics File meta information
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#
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# Revisions: 2011/01/25 - P. Harvey Created
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#
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# References: 1) http://www.libpgf.org/
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# 2) http://www.exiv2.org/
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#------------------------------------------------------------------------------
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package Image::ExifTool::PGF;
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use strict;
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use vars qw($VERSION);
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use Image::ExifTool qw(:DataAccess :Utils);
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$VERSION = '1.02';
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# PGF header information
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%Image::ExifTool::PGF::Main = (
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GROUPS => { 0 => 'File', 1 => 'File', 2 => 'Image' },
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PROCESS_PROC => \&Image::ExifTool::ProcessBinaryData,
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PRIORITY => 2, # (to take precedence over PNG tags from embedded image)
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NOTES => q{
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The following table lists information extracted from the header of
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Progressive Graphics File (PGF) images. As well, information is extracted
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from the embedded PNG metadata image if it exists. See
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L<http://www.libpgf.org/> for the PGF specification.
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},
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3 => {
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Name => 'PGFVersion',
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PrintConv => 'sprintf("0x%.2x", $val)',
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# this is actually a bitmask (ref digikam PGFtypes.h):
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# 0x02 - data structure PGFHeader of major version 2
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# 0x04 - 32-bit values
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# 0x08 - supports regions of interest
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# 0x10 - new coding scheme since major version 5
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# 0x20 - new HeaderSize: 32 bits instead of 16 bits
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},
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8 => { Name => 'ImageWidth', Format => 'int32u' },
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12 => { Name => 'ImageHeight', Format => 'int32u' },
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16 => 'PyramidLevels',
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17 => 'Quality',
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18 => 'BitsPerPixel',
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19 => 'ColorComponents',
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20 => {
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Name => 'ColorMode',
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RawConv => '$$self{PGFColorMode} = $val',
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PrintConvColumns => 2,
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PrintConv => {
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0 => 'Bitmap',
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1 => 'Grayscale',
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2 => 'Indexed',
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3 => 'RGB',
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4 => 'CMYK',
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7 => 'Multichannel',
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8 => 'Duotone',
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9 => 'Lab',
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},
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},
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21 => { Name => 'BackgroundColor', Format => 'int8u[3]' },
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);
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#------------------------------------------------------------------------------
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# Extract information from a PGF image
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# Inputs: 0) ExifTool object reference, 1) dirInfo reference
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# Returns: 1 on success, 0 if this wasn't a valid PGF file
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sub ProcessPGF($$)
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{
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my ($et, $dirInfo) = @_;
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my $raf = $$dirInfo{RAF};
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my $buff;
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# read header and check magic number
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return 0 unless $raf->Read($buff, 24) == 24 and $buff =~ /^PGF(.)/s;
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my $ver = ord $1;
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$et->SetFileType();
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SetByteOrder('II');
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# currently support only version 0x36
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unless ($ver == 0x36) {
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$et->Error(sprintf('Unsupported PGF version 0x%.2x', $ver));
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return 1;
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}
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# extract information from the PGF header
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my $tagTablePtr = GetTagTable('Image::ExifTool::PGF::Main');
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$et->ProcessDirectory({ DataPt => \$buff, DataPos => 0 }, $tagTablePtr);
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my $len = Get32u(\$buff, 4) - 16; # length of post-header data
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# skip colour table if necessary
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$len -= $raf->Seek(1024, 1) ? 1024 : $len if $$et{PGFColorMode} == 2;
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# extract information from the embedded metadata image (PNG format)
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if ($len > 0 and $len < 0x1000000 and $raf->Read($buff, $len) == $len) {
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$et->ExtractInfo(\$buff, { ReEntry => 1 });
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}
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return 1;
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}
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1; # end
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__END__
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=head1 NAME
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Image::ExifTool::PGF - Read Progressive Graphics File meta information
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=head1 SYNOPSIS
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This module is used by Image::ExifTool
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=head1 DESCRIPTION
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This module contains definitions required by Image::ExifTool to extract meta
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information from Progressive Graphics File (PGF) images.
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=head1 AUTHOR
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Copyright 2003-2018, Phil Harvey (phil at owl.phy.queensu.ca)
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This library is free software; you can redistribute it and/or modify it
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under the same terms as Perl itself.
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=head1 REFERENCES
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=over 4
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=item L<http://www.libpgf.org/>
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=item L<http://www.exiv2.org/>
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=back
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=head1 SEE ALSO
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L<Image::ExifTool::TagNames/PGF Tags>,
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L<Image::ExifTool(3pm)|Image::ExifTool>
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=cut
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