1 | #------------------------------------------------------------------------------
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2 | # File: BMP.pm
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3 | #
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4 | # Description: Read BMP meta information
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5 | #
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6 | # Revisions: 07/16/2005 - P. Harvey Created
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7 | #
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8 | # References: 1) http://www.fortunecity.com/skyscraper/windows/364/bmpffrmt.html
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9 | # 2) http://www.fourcc.org/rgb.php
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10 | #------------------------------------------------------------------------------
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11 |
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12 | package Image::ExifTool::BMP;
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13 |
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14 | use strict;
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15 | use vars qw($VERSION);
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16 | use Image::ExifTool qw(:DataAccess :Utils);
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17 |
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18 | $VERSION = '1.07';
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19 |
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20 | # BMP chunks
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21 | %Image::ExifTool::BMP::Main = (
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22 | PROCESS_PROC => \&Image::ExifTool::ProcessBinaryData,
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23 | GROUPS => { 0 => 'File', 1 => 'File', 2 => 'Image' },
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24 | NOTES => q{
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25 | There really isn't much meta information in a BMP file as such, just a bit
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26 | of image related information.
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27 | },
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28 | # 0 => size of bitmap structure:
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29 | # 12 bytes => 'OS/2 V1',
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30 | # 40 bytes => 'Windows V3',
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31 | # 64 bytes => 'OS/2 V2',
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32 | # 68 bytes => some bitmap structure in AVI videos
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33 | # 108 bytes => 'Windows V4',
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34 | # 124 bytes => 'Windows V5',
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35 | 4 => {
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36 | Name => 'ImageWidth',
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37 | Format => 'int32u',
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38 | },
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39 | 8 => {
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40 | Name => 'ImageHeight',
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41 | Format => 'int32s', # (negative when stored in top-to-bottom order)
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42 | ValueConv => 'abs($val)',
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43 | },
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44 | 12 => {
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45 | Name => 'Planes',
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46 | Format => 'int16u',
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47 | },
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48 | 14 => {
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49 | Name => 'BitDepth',
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50 | Format => 'int16u',
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51 | },
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52 | 16 => {
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53 | Name => 'Compression',
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54 | Format => 'int32u',
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55 | # (formatted as string[4] for some values in AVI images)
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56 | ValueConv => '$val > 256 ? unpack("A4",pack("V",$val)) : $val',
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57 | PrintConv => {
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58 | 0 => 'None',
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59 | 1 => '8-Bit RLE',
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60 | 2 => '4-Bit RLE',
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61 | 3 => 'Bitfields',
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62 | 4 => 'JPEG', #2
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63 | 5 => 'PNG', #2
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64 | # pass through ASCII video compression codec ID's
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65 | OTHER => sub {
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66 | my $val = shift;
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67 | # convert non-ascii characters
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68 | $val =~ s/([\0-\x1f\x7f-\xff])/sprintf('\\x%.2x',ord $1)/eg;
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69 | return $val;
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70 | },
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71 | },
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72 | },
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73 | 20 => {
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74 | Name => 'ImageLength',
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75 | Format => 'int32u',
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76 | },
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77 | 24 => {
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78 | Name => 'PixelsPerMeterX',
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79 | Format => 'int32u',
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80 | },
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81 | 28 => {
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82 | Name => 'PixelsPerMeterY',
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83 | Format => 'int32u',
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84 | },
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85 | 32 => {
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86 | Name => 'NumColors',
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87 | Format => 'int32u',
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88 | PrintConv => '$val ? $val : "Use BitDepth"',
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89 | },
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90 | 36 => {
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91 | Name => 'NumImportantColors',
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92 | Format => 'int32u',
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93 | PrintConv => '$val ? $val : "All"',
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94 | },
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95 | );
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96 |
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97 | # OS/2 12-byte bitmap header (ref http://www.fileformat.info/format/bmp/egff.htm)
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98 | %Image::ExifTool::BMP::OS2 = (
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99 | PROCESS_PROC => \&Image::ExifTool::ProcessBinaryData,
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100 | GROUPS => { 0 => 'File', 1 => 'File', 2 => 'Image' },
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101 | NOTES => 'Information extracted from OS/2-format BMP images.',
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102 | # 0 => size of bitmap structure (12)
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103 | 4 => { Name => 'ImageWidth', Format => 'int16u' },
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104 | 6 => { Name => 'ImageHeight', Format => 'int16u' },
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105 | 8 => { Name => 'Planes', Format => 'int16u' },
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106 | 10 => { Name => 'BitDepth', Format => 'int16u' },
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107 | );
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108 |
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109 | #------------------------------------------------------------------------------
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110 | # Extract EXIF information from a BMP image
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111 | # Inputs: 0) ExifTool object reference, 1) dirInfo reference
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112 | # Returns: 1 on success, 0 if this wasn't a valid BMP file
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113 | sub ProcessBMP($$)
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114 | {
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115 | my ($exifTool, $dirInfo) = @_;
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116 | my $raf = $$dirInfo{RAF};
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117 | my ($buff, $tagTablePtr);
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118 |
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119 | # verify this is a valid BMP file
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120 | return 0 unless $raf->Read($buff, 18) == 18;
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121 | return 0 unless $buff =~ /^BM/;
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122 | SetByteOrder('II');
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123 | my $len = Get32u(\$buff, 14);
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124 | return 0 unless $len == 12 or $len >= 40;
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125 | return 0 unless $raf->Seek(-4, 1) and $raf->Read($buff, $len) == $len;
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126 | $exifTool->SetFileType(); # set the FileType tag
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127 | my %dirInfo = (
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128 | DataPt => \$buff,
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129 | DirStart => 0,
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130 | DirLen => length($buff),
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131 | );
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132 | if ($len == 12) { # old OS/2 format BMP
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133 | $tagTablePtr = GetTagTable('Image::ExifTool::BMP::OS2');
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134 | } else {
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135 | $tagTablePtr = GetTagTable('Image::ExifTool::BMP::Main');
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136 | }
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137 | $exifTool->ProcessDirectory(\%dirInfo, $tagTablePtr);
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138 | return 1;
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139 | }
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140 |
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141 | 1; # end
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142 |
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143 | __END__
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144 |
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145 | =head1 NAME
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146 |
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147 | Image::ExifTool::BMP - Read BMP meta information
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148 |
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149 | =head1 SYNOPSIS
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150 |
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151 | This module is used by Image::ExifTool
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152 |
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153 | =head1 DESCRIPTION
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154 |
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155 | This module contains definitions required by Image::ExifTool to read BMP
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156 | (Windows Bitmap) images.
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157 |
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158 | =head1 AUTHOR
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159 |
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160 | Copyright 2003-2011, Phil Harvey (phil at owl.phy.queensu.ca)
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161 |
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162 | This library is free software; you can redistribute it and/or modify it
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163 | under the same terms as Perl itself.
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164 |
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165 | =head1 REFERENCES
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166 |
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167 | =over 4
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168 |
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169 | =item L<http://www.fortunecity.com/skyscraper/windows/364/bmpffrmt.html>
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170 |
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171 | =back
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172 |
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173 | =head1 SEE ALSO
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174 |
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175 | L<Image::ExifTool::TagNames/BMP Tags>,
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176 | L<Image::ExifTool(3pm)|Image::ExifTool>
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177 |
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178 | =cut
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179 |
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