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- #------------------------------------------------------------------------------
- # File: PPM.pm
- #
- # Description: Read and write PPM meta information
- #
- # Revisions: 09/03/2005 - P. Harvey Created
- #
- # References: 1) http://netpbm.sourceforge.net/doc/ppm.html
- # 2) http://netpbm.sourceforge.net/doc/pgm.html
- # 3) http://netpbm.sourceforge.net/doc/pbm.html
- #------------------------------------------------------------------------------
- package Image::ExifTool::PPM;
- use strict;
- use vars qw($VERSION);
- use Image::ExifTool qw(:DataAccess :Utils);
- $VERSION = '1.08';
- #------------------------------------------------------------------------------
- # Read or write information in a PPM/PGM/PBM image
- # Inputs: 0) ExifTool object reference, 1) Directory information reference
- # Returns: 1 on success, 0 if this wasn't a valid PPM file, -1 on write error
- sub ProcessPPM($$)
- {
- my ($et, $dirInfo) = @_;
- my $raf = $$dirInfo{RAF};
- my $outfile = $$dirInfo{OutFile};
- my $verbose = $et->Options('Verbose');
- my $out = $et->Options('TextOut');
- my ($buff, $num, $type, %info);
- #
- # read as much of the image as necessary to extract the header and comments
- #
- for (;;) {
- if (defined $buff) {
- # need to read some more data
- my $tmp;
- return 0 unless $raf->Read($tmp, 1024);
- $buff .= $tmp;
- } else {
- return 0 unless $raf->Read($buff, 1024);
- }
- # verify this is a valid PPM file
- return 0 unless $buff =~ /^P([1-6])\s+/g;
- $num = $1;
- # note: may contain comments starting with '#'
- if ($buff =~ /\G#/gc) {
- # must read more if we are in the middle of a comment
- next unless $buff =~ /\G ?(.*\n(#.*\n)*)\s*/g;
- $info{Comment} = $1;
- next if $buff =~ /\G#/gc;
- } else {
- delete $info{Comment};
- }
- next unless $buff =~ /\G(\S+)\s+(\S+)\s/g;
- $info{ImageWidth} = $1;
- $info{ImageHeight} = $2;
- $type = [qw{PPM PBM PGM}]->[$num % 3];
- last if $type eq 'PBM'; # (no MaxVal for PBM images)
- if ($buff =~ /\G\s*#/gc) {
- next unless $buff =~ /\G ?(.*\n(#.*\n)*)\s*/g;
- $info{Comment} = '' unless exists $info{Comment};
- $info{Comment} .= $1;
- next if $buff =~ /\G#/gc;
- }
- next unless $buff =~ /\G(\S+)\s/g;
- $info{MaxVal} = $1;
- last;
- }
- # validate numerical values
- foreach (keys %info) {
- next if $_ eq 'Comment';
- return 0 unless $info{$_} =~ /^\d+$/;
- }
- if (defined $info{Comment}) {
- $info{Comment} =~ s/^# ?//mg; # remove "# " at the start of each line
- $info{Comment} =~ s/\n$//; # remove trailing newline
- }
- $et->SetFileType($type);
- my $len = pos($buff);
- #
- # rewrite the file if requested
- #
- if ($outfile) {
- my $nvHash;
- my $newComment = $et->GetNewValue('Comment', \$nvHash);
- my $oldComment = $info{Comment};
- if ($et->IsOverwriting($nvHash, $oldComment)) {
- ++$$et{CHANGED};
- $et->VerboseValue('- Comment', $oldComment) if defined $oldComment;
- $et->VerboseValue('+ Comment', $newComment) if defined $newComment;
- } else {
- $newComment = $oldComment; # use existing comment
- }
- my $hdr = "P$num\n";
- if (defined $newComment) {
- $newComment =~ s/\n/\n# /g;
- $hdr .= "# $newComment\n";
- }
- $hdr .= "$info{ImageWidth} $info{ImageHeight}\n";
- $hdr .= "$info{MaxVal}\n" if $type ne 'PBM';
- # write header and start of image
- Write($outfile, $hdr, substr($buff, $len)) or return -1;
- # copy over the rest of the image
- while ($raf->Read($buff, 0x10000)) {
- Write($outfile, $buff) or return -1;
- }
- return 1;
- }
- #
- # save extracted information
- #
- if ($verbose > 2) {
- print $out "$type header ($len bytes):\n";
- HexDump(\$buff, $len, Out => $out);
- }
- my $tag;
- foreach $tag (qw{Comment ImageWidth ImageHeight MaxVal}) {
- $et->FoundTag($tag, $info{$tag}) if defined $info{$tag};
- }
- return 1;
- }
- 1; # end
- __END__
- =head1 NAME
- Image::ExifTool::PPM - Read and write PPM meta information
- =head1 SYNOPSIS
- This module is used by Image::ExifTool
- =head1 DESCRIPTION
- This module contains definitions required by Image::ExifTool to read and
- write PPM (Portable Pixel Map), PGM (Portable Gray Map) and PBM (Portable
- BitMap) images.
- =head1 AUTHOR
- Copyright 2003-2016, Phil Harvey (phil at owl.phy.queensu.ca)
- This library is free software; you can redistribute it and/or modify it
- under the same terms as Perl itself.
- =head1 REFERENCES
- =over 4
- =item L<http://netpbm.sourceforge.net/doc/ppm.html>
- =item L<http://netpbm.sourceforge.net/doc/pgm.html>
- =item L<http://netpbm.sourceforge.net/doc/pbm.html>
- =back
- =head1 SEE ALSO
- L<Image::ExifTool::TagNames/PPM Tags>,
- L<Image::ExifTool(3pm)|Image::ExifTool>
- =cut
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