543 lines
21 KiB
Perl
543 lines
21 KiB
Perl
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#------------------------------------------------------------------------------
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# File: GIF.pm
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#
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# Description: Read and write GIF meta information
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#
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# Revisions: 10/18/2005 - P. Harvey Separated from ExifTool.pm
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# 05/23/2008 - P. Harvey Added ability to read/write XMP
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# 10/28/2011 - P. Harvey Added ability to read/write ICC_Profile
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#
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# References: 1) http://www.w3.org/Graphics/GIF/spec-gif89a.txt
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# 2) http://www.adobe.com/devnet/xmp/
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# 3) http://graphcomp.com/info/specs/ani_gif.html
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# 4) http://www.color.org/icc_specs2.html
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#------------------------------------------------------------------------------
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package Image::ExifTool::GIF;
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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 = '1.12';
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# road map of directory locations in GIF images
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my %gifMap = (
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XMP => 'GIF',
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ICC_Profile => 'GIF',
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);
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%Image::ExifTool::GIF::Main = (
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GROUPS => { 2 => 'Image' },
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VARS => { NO_ID => 1 },
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NOTES => q{
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This table lists information extracted from GIF images. See
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L<http://www.w3.org/Graphics/GIF/spec-gif89a.txt> for the official GIF89a
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specification.
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},
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GIFVersion => { },
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FrameCount => { Notes => 'number of animated images' },
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Text => { Notes => 'text displayed in image' },
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Comment => {
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# for documentation only -- flag as writable for the docs, but
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# it won't appear in the TagLookup because there is no WRITE_PROC
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Writable => 1,
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},
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Duration => {
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Notes => 'duration of a single animation iteration',
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PrintConv => 'sprintf("%.2f s",$val)',
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},
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ScreenDescriptor => {
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SubDirectory => { TagTable => 'Image::ExifTool::GIF::Screen' },
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},
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# GIF89a application extensions:
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ExtensionAnimation => {
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SubDirectory => { TagTable => 'Image::ExifTool::GIF::Animate' },
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},
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ExtensionXMP => { # (for documentation only)
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SubDirectory => { TagTable => 'Image::ExifTool::XMP::Main' },
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},
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ExtensionICC => { # (for documentation only)
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SubDirectory => { TagTable => 'Image::ExifTool::ICC_Profile::Main' },
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},
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);
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# GIF locical screen descriptor
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%Image::ExifTool::GIF::Screen = (
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PROCESS_PROC => \&Image::ExifTool::ProcessBinaryData,
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GROUPS => { 2 => 'Image' },
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NOTES => 'Information extracted from the GIF logical screen descriptor.',
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0 => {
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Name => 'ImageWidth',
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Format => 'int16u',
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},
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2 => {
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Name => 'ImageHeight',
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Format => 'int16u',
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},
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4.1 => {
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Name => 'HasColorMap',
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Mask => 0x80,
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PrintConv => { 0x00 => 'No', 0x80 => 'Yes' },
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},
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4.2 => {
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Name => 'ColorResolutionDepth',
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Mask => 0x70,
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ValueConv => '($val >> 4) + 1',
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},
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4.3 => {
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Name => 'BitsPerPixel',
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Mask => 0x07,
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ValueConv => '$val + 1',
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},
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5 => 'BackgroundColor',
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);
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# GIF Netscape 2.0 animation extension
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%Image::ExifTool::GIF::Animate = (
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PROCESS_PROC => \&Image::ExifTool::ProcessBinaryData,
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GROUPS => { 2 => 'Image' },
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NOTES => 'Information extracted from the "NETSCAPE2.0" animation extension.',
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2 => {
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Name => 'AnimationIterations',
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Format => 'int16u',
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PrintConv => '$val ? $val : "Infinite"',
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},
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);
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#------------------------------------------------------------------------------
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# Process meta information in GIF image
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# Inputs: 0) ExifTool object reference, 1) Directory information ref
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# Returns: 1 on success, 0 if this wasn't a valid GIF file, or -1 if
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# an output file was specified and a write error occurred
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sub ProcessGIF($$)
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{
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my ($et, $dirInfo) = @_;
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my $outfile = $$dirInfo{OutFile};
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my $raf = $$dirInfo{RAF};
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my $verbose = $et->Options('Verbose');
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my $out = $et->Options('TextOut');
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my ($a, $s, $ch, $length, $buff);
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my ($err, $newComment, $setComment, $nvComment);
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my ($addDirs, %doneDir);
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my ($frameCount, $delayTime) = (0, 0);
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# verify this is a valid GIF file
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return 0 unless $raf->Read($buff, 6) == 6
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and $buff =~ /^GIF(8[79]a)$/
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and $raf->Read($s, 7) == 7;
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my $ver = $1;
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my $rtnVal = 0;
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my $tagTablePtr = GetTagTable('Image::ExifTool::GIF::Main');
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SetByteOrder('II');
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if ($outfile) {
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$et->InitWriteDirs(\%gifMap, 'XMP'); # make XMP the preferred group for GIF
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$addDirs = $$et{ADD_DIRS};
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# determine if we are editing the File:Comment tag
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my $delGroup = $$et{DEL_GROUP};
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$newComment = $et->GetNewValue('Comment', \$nvComment);
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$setComment = 1 if $nvComment or $$delGroup{File};
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# change to GIF 89a if adding comment, XMP or ICC_Profile
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$buff = 'GIF89a' if $$addDirs{XMP} or $$addDirs{ICC_Profile} or defined $newComment;
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Write($outfile, $buff, $s) or $err = 1;
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} else {
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$et->SetFileType(); # set file type
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$et->HandleTag($tagTablePtr, 'GIFVersion', $ver);
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$et->HandleTag($tagTablePtr, 'ScreenDescriptor', $s);
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}
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my $flags = Get8u(\$s, 4);
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if ($flags & 0x80) { # does this image contain a color table?
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# calculate color table size
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$length = 3 * (2 << ($flags & 0x07));
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$raf->Read($buff, $length) == $length or return 0; # skip color table
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Write($outfile, $buff) or $err = 1 if $outfile;
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}
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#
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# loop through GIF blocks
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#
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Block:
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for (;;) {
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last unless $raf->Read($ch, 1);
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# write out any new metadata now if this isn't an extension block
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if ($outfile and ord($ch) != 0x21) {
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# write the comment first if necessary
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if (defined $newComment and $$nvComment{IsCreating}) {
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# write comment marker
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Write($outfile, "\x21\xfe") or $err = 1;
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$verbose and print $out " + Comment = $newComment\n";
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my $len = length($newComment);
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# write out the comment in 255-byte chunks, each
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# chunk beginning with a length byte
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my $n;
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for ($n=0; $n<$len; $n+=255) {
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my $size = $len - $n;
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$size > 255 and $size = 255;
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my $str = substr($newComment,$n,$size);
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Write($outfile, pack('C',$size), $str) or $err = 1;
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}
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Write($outfile, "\0") or $err = 1; # empty chunk as terminator
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undef $newComment;
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undef $nvComment; # delete any other extraneous comments
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++$$et{CHANGED}; # increment file changed flag
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}
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# add application extension containing XMP block if necessary
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# (this will place XMP before the first non-extension block)
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if (exists $$addDirs{XMP} and not defined $doneDir{XMP}) {
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$doneDir{XMP} = 1;
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# write new XMP data
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my $xmpTable = GetTagTable('Image::ExifTool::XMP::Main');
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my %dirInfo = ( Parent => 'GIF' );
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$verbose and print $out "Creating XMP application extension block:\n";
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$buff = $et->WriteDirectory(\%dirInfo, $xmpTable);
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if (defined $buff and length $buff) {
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my $lz = pack('C*',1,reverse(0..255),0);
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Write($outfile, "\x21\xff\x0bXMP DataXMP", $buff, $lz) or $err = 1;
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++$doneDir{XMP}; # set to 2 to indicate we added XMP
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} else {
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$verbose and print $out " -> no XMP to add\n";
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}
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}
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# add application extension containing ICC_Profile if necessary
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if (exists $$addDirs{ICC_Profile} and not defined $doneDir{ICC_Profile}) {
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$doneDir{ICC_Profile} = 1;
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# write new ICC_Profile
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my $iccTable = GetTagTable('Image::ExifTool::ICC_Profile::Main');
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my %dirInfo = ( Parent => 'GIF' );
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$verbose and print $out "Creating ICC_Profile application extension block:\n";
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$buff = $et->WriteDirectory(\%dirInfo, $iccTable);
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if (defined $buff and length $buff) {
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my $pos = 0;
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Write($outfile, "\x21\xff\x0bICCRGBG1012") or $err = 1;
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my $len = length $buff;
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while ($pos < $len) {
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my $n = $len - $pos;
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$n = 255 if $n > 255;
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Write($outfile, chr($n), substr($buff, $pos, $n)) or $err = 1;
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$pos += $n;
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}
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Write($outfile, "\0") or $err = 1; # write null terminator
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++$doneDir{ICC_Profile}; # set to 2 to indicate we added a new profile
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} else {
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$verbose and print $out " -> no ICC_Profile to add\n";
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}
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}
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}
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if (ord($ch) == 0x2c) {
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++$frameCount;
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Write($outfile, $ch) or $err = 1 if $outfile;
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# image descriptor
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last unless $raf->Read($buff, 8) == 8 and $raf->Read($ch, 1);
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Write($outfile, $buff, $ch) or $err = 1 if $outfile;
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if ($verbose) {
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my ($left, $top, $w, $h) = unpack('v*', $buff);
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print $out "Image: left=$left top=$top width=$w height=$h\n";
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}
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if (ord($ch) & 0x80) { # does color table exist?
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$length = 3 * (2 << (ord($ch) & 0x07));
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# skip the color table
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last unless $raf->Read($buff, $length) == $length;
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Write($outfile, $buff) or $err = 1 if $outfile;
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}
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# skip "LZW Minimum Code Size" byte
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last unless $raf->Read($buff, 1);
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Write($outfile,$buff) or $err = 1 if $outfile;
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# skip image blocks
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for (;;) {
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last unless $raf->Read($ch, 1);
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Write($outfile, $ch) or $err = 1 if $outfile;
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last unless ord($ch);
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last unless $raf->Read($buff, ord($ch));
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Write($outfile,$buff) or $err = 1 if $outfile;
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}
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next; # continue with next field
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}
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# last if ord($ch) == 0x3b; # normal end of GIF marker
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unless (ord($ch) == 0x21) {
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if ($outfile) {
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Write($outfile, $ch) or $err = 1;
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# copy the rest of the file
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while ($raf->Read($buff, 65536)) {
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Write($outfile, $buff) or $err = 1;
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}
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}
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$rtnVal = 1;
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last;
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}
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# get extension block type/size
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last unless $raf->Read($s, 2) == 2;
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# get marker and block size
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($a,$length) = unpack("C"x2, $s);
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if ($a == 0xfe) { # comment extension
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my $comment = '';
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while ($length) {
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last unless $raf->Read($buff, $length) == $length;
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if ($verbose > 2 and not $outfile) {
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HexDump(\$buff, undef, Out => $out);
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}
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# add buffer to comment string
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$comment .= $buff;
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last unless $raf->Read($ch, 1); # read next block header
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$length = ord($ch); # get next block size
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}
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last if $length; # was a read error if length isn't zero
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if ($outfile) {
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my $isOverwriting;
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if ($setComment) {
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if ($nvComment) {
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$isOverwriting = $et->IsOverwriting($nvComment,$comment);
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# get new comment again (may have been shifted)
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$newComment = $et->GetNewValue($nvComment) if defined $newComment;
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} else {
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# group delete, or deleting additional comments after writing one
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$isOverwriting = 1;
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}
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}
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if ($isOverwriting) {
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++$$et{CHANGED}; # increment file changed flag
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$et->VerboseValue('- Comment', $comment);
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$comment = $newComment;
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$et->VerboseValue('+ Comment', $comment) if defined $comment;
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undef $nvComment; # just delete remaining comments
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} else {
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undef $setComment; # leave remaining comments alone
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}
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if (defined $comment) {
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# write comment marker
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Write($outfile, "\x21\xfe") or $err = 1;
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my $len = length($comment);
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# write out the comment in 255-byte chunks, each
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# chunk beginning with a length byte
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my $n;
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for ($n=0; $n<$len; $n+=255) {
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my $size = $len - $n;
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$size > 255 and $size = 255;
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my $str = substr($comment,$n,$size);
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Write($outfile, pack('C',$size), $str) or $err = 1;
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}
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Write($outfile, "\0") or $err = 1; # empty chunk as terminator
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}
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undef $newComment; # don't write the new comment again
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} else {
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$rtnVal = 1;
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$et->FoundTag('Comment', $comment) if $comment;
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undef $comment;
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# assume no more than one comment in FastScan mode
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last if $et->Options('FastScan');
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}
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next;
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} elsif ($a == 0xff and $length == 0x0b) { # application extension
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last unless $raf->Read($buff, $length) == $length;
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if ($verbose) {
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my @a = unpack('a8a3', $buff);
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s/\0.*//s foreach @a;
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print $out "Application Extension: @a\n";
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}
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if ($buff eq 'XMP DataXMP') { # XMP data (ref 2)
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my $hdr = "$ch$s$buff";
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# read XMP data
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my $xmp = '';
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for (;;) {
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||
|
|
$raf->Read($ch, 1) or last Block; # read next block header
|
||
|
|
$length = ord($ch) or last; # get next block size
|
||
|
|
$raf->Read($buff, $length) == $length or last Block;
|
||
|
|
$xmp .= $ch . $buff;
|
||
|
|
}
|
||
|
|
# get length of XMP without landing zone data
|
||
|
|
# (note that LZ data may not be exactly the same as what we use)
|
||
|
|
my $xmpLen;
|
||
|
|
if ($xmp =~ /<\?xpacket end=['"][wr]['"]\?>/g) {
|
||
|
|
$xmpLen = pos($xmp);
|
||
|
|
} else {
|
||
|
|
$xmpLen = length($xmp);
|
||
|
|
}
|
||
|
|
my %dirInfo = (
|
||
|
|
DataPt => \$xmp,
|
||
|
|
DataLen => length $xmp,
|
||
|
|
DirLen => $xmpLen,
|
||
|
|
Parent => 'GIF',
|
||
|
|
);
|
||
|
|
my $xmpTable = GetTagTable('Image::ExifTool::XMP::Main');
|
||
|
|
if ($outfile) {
|
||
|
|
if ($doneDir{XMP} and $doneDir{XMP} > 1) {
|
||
|
|
$et->Warn('Duplicate XMP block created');
|
||
|
|
}
|
||
|
|
$buff = $et->WriteDirectory(\%dirInfo, $xmpTable);
|
||
|
|
if (not defined $buff) {
|
||
|
|
# rewrite original XMP with landing zone (adding back null terminator)
|
||
|
|
Write($outfile, $hdr, $xmp, "\0") or $err = 1;
|
||
|
|
$doneDir{XMP} = 1;
|
||
|
|
} elsif (length $buff) {
|
||
|
|
if ($buff =~ /\0/) { # (check just to be safe)
|
||
|
|
$et->Error('XMP contained NULL character');
|
||
|
|
} else {
|
||
|
|
# write new XMP and landing zone
|
||
|
|
my $lz = pack('C*',1,reverse(0..255),0);
|
||
|
|
Write($outfile, $hdr, $buff, $lz) or $err = 1;
|
||
|
|
}
|
||
|
|
$doneDir{XMP} = 1;
|
||
|
|
} # else we are deleting the XMP
|
||
|
|
} else {
|
||
|
|
$et->ProcessDirectory(\%dirInfo, $xmpTable);
|
||
|
|
}
|
||
|
|
next;
|
||
|
|
|
||
|
|
} elsif ($buff eq 'ICCRGBG1012') { # ICC_Profile extension (ref 4)
|
||
|
|
|
||
|
|
my $hdr = "$ch$s$buff";
|
||
|
|
# read ICC profile data
|
||
|
|
my $icc_profile = '';
|
||
|
|
for (;;) {
|
||
|
|
$raf->Read($ch, 1) or last Block; # read next block header
|
||
|
|
$length = ord($ch) or last; # get next block size
|
||
|
|
$raf->Read($buff, $length) == $length or last Block;
|
||
|
|
$icc_profile .= $buff;
|
||
|
|
}
|
||
|
|
my %dirInfo = (
|
||
|
|
DataPt => \$icc_profile,
|
||
|
|
DataLen => length $icc_profile,
|
||
|
|
DirLen => length $icc_profile,
|
||
|
|
Parent => 'GIF',
|
||
|
|
);
|
||
|
|
my $iccTable = GetTagTable('Image::ExifTool::ICC_Profile::Main');
|
||
|
|
if ($outfile) {
|
||
|
|
if ($doneDir{ICC_Profile} and $doneDir{ICC_Profile} > 1) {
|
||
|
|
$et->Warn('Duplicate ICC_Profile block created');
|
||
|
|
}
|
||
|
|
$buff = $et->WriteDirectory(\%dirInfo, $iccTable);
|
||
|
|
# rewrite original ICC_Profile if nothing changed
|
||
|
|
$buff = $icc_profile unless defined $buff;
|
||
|
|
if (length $buff) {
|
||
|
|
# write ICC profile sub-blocks
|
||
|
|
my $pos = 0;
|
||
|
|
Write($outfile, $hdr) or $err = 1;
|
||
|
|
my $len = length $buff;
|
||
|
|
while ($pos < $len) {
|
||
|
|
my $n = $len - $pos;
|
||
|
|
$n = 255 if $n > 255;
|
||
|
|
Write($outfile, chr($n), substr($buff, $pos, $n)) or $err = 1;
|
||
|
|
$pos += $n;
|
||
|
|
}
|
||
|
|
Write($outfile, "\0") or $err = 1; # write null terminator
|
||
|
|
$doneDir{ICC_Profile} = 1;
|
||
|
|
} # else we are deleting the ICC profile
|
||
|
|
} else {
|
||
|
|
$et->ProcessDirectory(\%dirInfo, $iccTable);
|
||
|
|
}
|
||
|
|
next;
|
||
|
|
|
||
|
|
} elsif ($buff eq 'NETSCAPE2.0') { # animated GIF extension (ref 3)
|
||
|
|
|
||
|
|
$raf->Read($buff, 5) == 5 or last;
|
||
|
|
# make sure this contains the expected data
|
||
|
|
if ($buff =~ /^\x03\x01(..)\0$/s) {
|
||
|
|
$et->HandleTag($tagTablePtr, 'ExtensionAnimation', $buff);
|
||
|
|
}
|
||
|
|
$raf->Seek(-$length-5, 1) or last; # seek back to start of block
|
||
|
|
|
||
|
|
} else {
|
||
|
|
|
||
|
|
# rewind to start of application extension to copy the unknown block
|
||
|
|
$raf->Seek(-$length, 1) or last;
|
||
|
|
}
|
||
|
|
|
||
|
|
} elsif ($a == 0xf9 and $length == 4) { # graphic control extension
|
||
|
|
|
||
|
|
last unless $raf->Read($buff, $length) == $length;
|
||
|
|
# sum the indivual delay times
|
||
|
|
my $delay = Get16u(\$buff, 1);
|
||
|
|
$delayTime += $delay;
|
||
|
|
$verbose and printf $out "Graphic Control: delay=%.2f\n", $delay / 100;
|
||
|
|
$raf->Seek(-$length, 1) or last;
|
||
|
|
|
||
|
|
} elsif ($a == 0x01 and $length == 12) { # plain text extension
|
||
|
|
|
||
|
|
last unless $raf->Read($buff, $length) == $length;
|
||
|
|
Write($outfile, $ch, $s, $buff) or $err = 1 if $outfile;
|
||
|
|
if ($verbose) {
|
||
|
|
my ($left, $top, $w, $h) = unpack('v4', $buff);
|
||
|
|
print $out "Text: left=$left top=$top width=$w height=$h\n";
|
||
|
|
}
|
||
|
|
my $text = '';
|
||
|
|
for (;;) {
|
||
|
|
last unless $raf->Read($ch, 1);
|
||
|
|
$length = ord($ch) or last;
|
||
|
|
last unless $raf->Read($buff, $length) == $length;
|
||
|
|
Write($outfile, $ch, $buff) or $err = 1 if $outfile; # write block
|
||
|
|
$text .= $buff;
|
||
|
|
}
|
||
|
|
Write($outfile, "\0") or $err = 1 if $outfile; # write terminator block
|
||
|
|
$et->HandleTag($tagTablePtr, 'Text', $text);
|
||
|
|
next;
|
||
|
|
}
|
||
|
|
Write($outfile, $ch, $s) or $err = 1 if $outfile;
|
||
|
|
# skip the block
|
||
|
|
while ($length) {
|
||
|
|
last unless $raf->Read($buff, $length) == $length;
|
||
|
|
Write($outfile, $buff) or $err = 1 if $outfile;
|
||
|
|
last unless $raf->Read($ch, 1); # read next block header
|
||
|
|
Write($outfile, $ch) or $err = 1 if $outfile;
|
||
|
|
$length = ord($ch); # get next block size
|
||
|
|
}
|
||
|
|
}
|
||
|
|
unless ($outfile) {
|
||
|
|
$et->HandleTag($tagTablePtr, 'FrameCount', $frameCount) if $frameCount > 1;
|
||
|
|
$et->HandleTag($tagTablePtr, 'Duration', $delayTime/100) if $delayTime;
|
||
|
|
}
|
||
|
|
|
||
|
|
# set return value to -1 if we only had a write error
|
||
|
|
$rtnVal = -1 if $rtnVal and $err;
|
||
|
|
return $rtnVal;
|
||
|
|
}
|
||
|
|
|
||
|
|
|
||
|
|
1; #end
|
||
|
|
|
||
|
|
__END__
|
||
|
|
|
||
|
|
=head1 NAME
|
||
|
|
|
||
|
|
Image::ExifTool::GIF - Read and write GIF meta information
|
||
|
|
|
||
|
|
=head1 SYNOPSIS
|
||
|
|
|
||
|
|
This module is loaded automatically by Image::ExifTool when required.
|
||
|
|
|
||
|
|
=head1 DESCRIPTION
|
||
|
|
|
||
|
|
This module contains definitions required by Image::ExifTool to read and
|
||
|
|
write GIF meta information.
|
||
|
|
|
||
|
|
=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://www.w3.org/Graphics/GIF/spec-gif89a.txt>
|
||
|
|
|
||
|
|
=item L<http://www.adobe.com/devnet/xmp/>
|
||
|
|
|
||
|
|
=item L<http://graphcomp.com/info/specs/ani_gif.html>
|
||
|
|
|
||
|
|
=item L<http://www.color.org/icc_specs2.html>
|
||
|
|
|
||
|
|
=back
|
||
|
|
|
||
|
|
=head1 SEE ALSO
|
||
|
|
|
||
|
|
L<Image::ExifTool(3pm)|Image::ExifTool>
|
||
|
|
|
||
|
|
=cut
|