170 lines
4.9 KiB
Perl
Executable File
170 lines
4.9 KiB
Perl
Executable File
#------------------------------------------------------------------------------
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# File: PPM.pm
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#
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# Description: Read and write PPM meta information
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#
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# Revisions: 09/03/2005 - P. Harvey Created
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#
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# References: 1) http://netpbm.sourceforge.net/doc/ppm.html
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# 2) http://netpbm.sourceforge.net/doc/pgm.html
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# 3) http://netpbm.sourceforge.net/doc/pbm.html
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#------------------------------------------------------------------------------
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package Image::ExifTool::PPM;
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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 = '1.08';
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#------------------------------------------------------------------------------
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# Read or write information in a PPM/PGM/PBM image
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# Inputs: 0) ExifTool object reference, 1) Directory information reference
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# Returns: 1 on success, 0 if this wasn't a valid PPM file, -1 on write error
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sub ProcessPPM($$)
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{
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my ($et, $dirInfo) = @_;
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my $raf = $$dirInfo{RAF};
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my $outfile = $$dirInfo{OutFile};
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my $verbose = $et->Options('Verbose');
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my $out = $et->Options('TextOut');
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my ($buff, $num, $type, %info);
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#
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# read as much of the image as necessary to extract the header and comments
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#
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for (;;) {
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if (defined $buff) {
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# need to read some more data
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my $tmp;
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return 0 unless $raf->Read($tmp, 1024);
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$buff .= $tmp;
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} else {
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return 0 unless $raf->Read($buff, 1024);
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}
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# verify this is a valid PPM file
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return 0 unless $buff =~ /^P([1-6])\s+/g;
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$num = $1;
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# note: may contain comments starting with '#'
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if ($buff =~ /\G#/gc) {
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# must read more if we are in the middle of a comment
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next unless $buff =~ /\G ?(.*\n(#.*\n)*)\s*/g;
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$info{Comment} = $1;
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next if $buff =~ /\G#/gc;
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} else {
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delete $info{Comment};
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}
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next unless $buff =~ /\G(\S+)\s+(\S+)\s/g;
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$info{ImageWidth} = $1;
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$info{ImageHeight} = $2;
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$type = [qw{PPM PBM PGM}]->[$num % 3];
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last if $type eq 'PBM'; # (no MaxVal for PBM images)
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if ($buff =~ /\G\s*#/gc) {
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next unless $buff =~ /\G ?(.*\n(#.*\n)*)\s*/g;
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$info{Comment} = '' unless exists $info{Comment};
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$info{Comment} .= $1;
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next if $buff =~ /\G#/gc;
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}
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next unless $buff =~ /\G(\S+)\s/g;
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$info{MaxVal} = $1;
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last;
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}
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# validate numerical values
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foreach (keys %info) {
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next if $_ eq 'Comment';
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return 0 unless $info{$_} =~ /^\d+$/;
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}
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if (defined $info{Comment}) {
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$info{Comment} =~ s/^# ?//mg; # remove "# " at the start of each line
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$info{Comment} =~ s/\n$//; # remove trailing newline
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}
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$et->SetFileType($type);
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my $len = pos($buff);
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#
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# rewrite the file if requested
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#
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if ($outfile) {
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my $nvHash;
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my $newComment = $et->GetNewValue('Comment', \$nvHash);
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my $oldComment = $info{Comment};
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if ($et->IsOverwriting($nvHash, $oldComment)) {
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++$$et{CHANGED};
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$et->VerboseValue('- Comment', $oldComment) if defined $oldComment;
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$et->VerboseValue('+ Comment', $newComment) if defined $newComment;
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} else {
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$newComment = $oldComment; # use existing comment
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}
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my $hdr = "P$num\n";
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if (defined $newComment) {
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$newComment =~ s/\n/\n# /g;
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$hdr .= "# $newComment\n";
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}
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$hdr .= "$info{ImageWidth} $info{ImageHeight}\n";
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$hdr .= "$info{MaxVal}\n" if $type ne 'PBM';
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# write header and start of image
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Write($outfile, $hdr, substr($buff, $len)) or return -1;
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# copy over the rest of the image
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while ($raf->Read($buff, 0x10000)) {
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Write($outfile, $buff) or return -1;
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}
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return 1;
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}
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#
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# save extracted information
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#
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if ($verbose > 2) {
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print $out "$type header ($len bytes):\n";
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HexDump(\$buff, $len, Out => $out);
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}
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my $tag;
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foreach $tag (qw{Comment ImageWidth ImageHeight MaxVal}) {
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$et->FoundTag($tag, $info{$tag}) if defined $info{$tag};
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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::PPM - Read and write PPM 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 read and
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write PPM (Portable Pixel Map), PGM (Portable Gray Map) and PBM (Portable
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BitMap) images.
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=head1 AUTHOR
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Copyright 2003-2016, 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://netpbm.sourceforge.net/doc/ppm.html>
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=item L<http://netpbm.sourceforge.net/doc/pgm.html>
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=item L<http://netpbm.sourceforge.net/doc/pbm.html>
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=back
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=head1 SEE ALSO
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L<Image::ExifTool::TagNames/PPM Tags>,
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L<Image::ExifTool(3pm)|Image::ExifTool>
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=cut
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