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#------------------------------------------------------------------------------
# File: BMP.pm
#
# Description: Read BMP meta information
#
# Revisions: 07/16/2005 - P. Harvey Created
#
# References: 1) http://www.fortunecity.com/skyscraper/windows/364/bmpffrmt.html
# 2) http://www.fourcc.org/rgb.php
#------------------------------------------------------------------------------
package Image::ExifTool::BMP;
use strict;
use vars qw($VERSION);
use Image::ExifTool qw(:DataAccess :Utils);
$VERSION = '1.08';
# BMP chunks
%Image::ExifTool::BMP::Main = (
PROCESS_PROC => \&Image::ExifTool::ProcessBinaryData,
GROUPS => { 0 => 'File', 1 => 'File', 2 => 'Image' },
NOTES => q{
There really isn't much meta information in a BMP file as such, just a bit
of image related information.
},
# 0 => size of bitmap structure:
# 12 bytes => 'OS/2 V1',
# 40 bytes => 'Windows V3',
# 64 bytes => 'OS/2 V2',
# 68 bytes => some bitmap structure in AVI videos
# 108 bytes => 'Windows V4',
# 124 bytes => 'Windows V5',
4 => {
Name => 'ImageWidth',
Format => 'int32u',
},
8 => {
Name => 'ImageHeight',
Format => 'int32s', # (negative when stored in top-to-bottom order)
ValueConv => 'abs($val)',
},
12 => {
Name => 'Planes',
Format => 'int16u',
},
14 => {
Name => 'BitDepth',
Format => 'int16u',
},
16 => {
Name => 'Compression',
Format => 'int32u',
# (formatted as string[4] for some values in AVI images)
ValueConv => '$val > 256 ? unpack("A4",pack("V",$val)) : $val',
PrintConv => {
0 => 'None',
1 => '8-Bit RLE',
2 => '4-Bit RLE',
3 => 'Bitfields',
4 => 'JPEG', #2
5 => 'PNG', #2
# pass through ASCII video compression codec ID's
OTHER => sub {
my $val = shift;
# convert non-ascii characters
$val =~ s/([\0-\x1f\x7f-\xff])/sprintf('\\x%.2x',ord $1)/eg;
return $val;
},
},
},
20 => {
Name => 'ImageLength',
Format => 'int32u',
},
24 => {
Name => 'PixelsPerMeterX',
Format => 'int32u',
},
28 => {
Name => 'PixelsPerMeterY',
Format => 'int32u',
},
32 => {
Name => 'NumColors',
Format => 'int32u',
PrintConv => '$val ? $val : "Use BitDepth"',
},
36 => {
Name => 'NumImportantColors',
Format => 'int32u',
PrintConv => '$val ? $val : "All"',
},
);
# OS/2 12-byte bitmap header (ref http://www.fileformat.info/format/bmp/egff.htm)
%Image::ExifTool::BMP::OS2 = (
PROCESS_PROC => \&Image::ExifTool::ProcessBinaryData,
GROUPS => { 0 => 'File', 1 => 'File', 2 => 'Image' },
NOTES => 'Information extracted from OS/2-format BMP images.',
# 0 => size of bitmap structure (12)
4 => { Name => 'ImageWidth', Format => 'int16u' },
6 => { Name => 'ImageHeight', Format => 'int16u' },
8 => { Name => 'Planes', Format => 'int16u' },
10 => { Name => 'BitDepth', Format => 'int16u' },
);
#------------------------------------------------------------------------------
# Extract EXIF information from a BMP image
# Inputs: 0) ExifTool object reference, 1) dirInfo reference
# Returns: 1 on success, 0 if this wasn't a valid BMP file
sub ProcessBMP($$)
{
my ($et, $dirInfo) = @_;
my $raf = $$dirInfo{RAF};
my ($buff, $tagTablePtr);
# verify this is a valid BMP file
return 0 unless $raf->Read($buff, 18) == 18;
return 0 unless $buff =~ /^BM/;
SetByteOrder('II');
my $len = Get32u(\$buff, 14);
return 0 unless $len == 12 or $len >= 40;
return 0 unless $raf->Seek(-4, 1) and $raf->Read($buff, $len) == $len;
$et->SetFileType(); # set the FileType tag
my %dirInfo = (
DataPt => \$buff,
DirStart => 0,
DirLen => length($buff),
);
if ($len == 12) { # old OS/2 format BMP
$tagTablePtr = GetTagTable('Image::ExifTool::BMP::OS2');
} else {
$tagTablePtr = GetTagTable('Image::ExifTool::BMP::Main');
}
$et->ProcessDirectory(\%dirInfo, $tagTablePtr);
return 1;
}
1; # end
__END__
=head1 NAME
Image::ExifTool::BMP - Read BMP meta information
=head1 SYNOPSIS
This module is used by Image::ExifTool
=head1 DESCRIPTION
This module contains definitions required by Image::ExifTool to read BMP
(Windows Bitmap) images.
=head1 AUTHOR
Copyright 2003-2014, 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.fortunecity.com/skyscraper/windows/364/bmpffrmt.html>
=back
=head1 SEE ALSO
L<Image::ExifTool::TagNames/BMP Tags>,
L<Image::ExifTool(3pm)|Image::ExifTool>
=cut
|
