includes/media/ExifBitmap.php

   1 <?php
   2 /**
   3  * Handler for bitmap images with exif metadata.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Media
  22  */
  23
  24 /**
  25  * Stuff specific to JPEG and (built-in) TIFF handler.
  26  * All metadata related, since both JPEG and TIFF support Exif.
  27  *
  28  * @ingroup Media
  29  */
  30 class ExifBitmapHandler extends BitmapHandler {
  31
  32         const BROKEN_FILE = '-1'; // error extracting metadata
  33         const OLD_BROKEN_FILE = '0'; // outdated error extracting metadata.
  34
  35         function convertMetadataVersion( $metadata, $version = 1 ) {
  36                 // basically flattens arrays.
  37                 $version = explode( ';', $version, 2 );
  38                 $version = intval( $version[0] );
  39                 if ( $version < 1 || $version >= 2 ) {
  40                         return $metadata;
  41                 }
  42
  43                 $avoidHtml = true;
  44
  45                 if ( !is_array( $metadata ) ) {
  46                         $metadata = unserialize( $metadata );
  47                 }
  48                 if ( !isset( $metadata['MEDIAWIKI_EXIF_VERSION'] ) || $metadata['MEDIAWIKI_EXIF_VERSION'] != 2 ) {
  49                         return $metadata;
  50                 }
  51
  52                 // Treat Software as a special case because in can contain
  53                 // an array of (SoftwareName, Version).
  54                 if ( isset( $metadata['Software'] )
  55                         && is_array( $metadata['Software'] )
  56                         && is_array( $metadata['Software'][0] )
  57                         && isset( $metadata['Software'][0][0] )
  58                         && isset( $metadata['Software'][0][1] )
  59                 ) {
  60                         $metadata['Software'] = $metadata['Software'][0][0] . ' (Version '
  61                                 . $metadata['Software'][0][1] . ')';
  62                 }
  63
  64                 // ContactInfo also has to be dealt with specially
  65                 if ( isset( $metadata['Contact'] ) ) {
  66                         $metadata['Contact'] =
  67                                 FormatMetadata::collapseContactInfo(
  68                                         $metadata['Contact'] );
  69                 }
  70
  71                 foreach ( $metadata as &$val ) {
  72                         if ( is_array( $val ) ) {
  73                                 $val = FormatMetadata::flattenArray( $val, 'ul', $avoidHtml );
  74                         }
  75                 }
  76                 $metadata['MEDIAWIKI_EXIF_VERSION'] = 1;
  77                 return $metadata;
  78         }
  79
  80         function isMetadataValid( $image, $metadata ) {
  81                 global $wgShowEXIF;
  82                 if ( !$wgShowEXIF ) {
  83                         # Metadata disabled and so an empty field is expected
  84                         return self::METADATA_GOOD;
  85                 }
  86                 if ( $metadata === self::OLD_BROKEN_FILE ) {
  87                         # Old special value indicating that there is no Exif data in the file.
  88                         # or that there was an error well extracting the metadata.
  89                         wfDebug( __METHOD__ . ": back-compat version\n" );
  90                         return self::METADATA_COMPATIBLE;
  91                 }
  92                 if ( $metadata === self::BROKEN_FILE ) {
  93                         return self::METADATA_GOOD;
  94                 }
  95                 wfSuppressWarnings();
  96                 $exif = unserialize( $metadata );
  97                 wfRestoreWarnings();
  98                 if ( !isset( $exif['MEDIAWIKI_EXIF_VERSION'] ) ||
  99                         $exif['MEDIAWIKI_EXIF_VERSION'] != Exif::version() )
 100                 {
 101                         if ( isset( $exif['MEDIAWIKI_EXIF_VERSION'] ) &&
 102                                 $exif['MEDIAWIKI_EXIF_VERSION'] == 1 )
 103                         {
 104                                 //back-compatible but old
 105                                 wfDebug( __METHOD__ . ": back-compat version\n" );
 106                                 return self::METADATA_COMPATIBLE;
 107                         }
 108                         # Wrong (non-compatible) version
 109                         wfDebug( __METHOD__ . ": wrong version\n" );
 110                         return self::METADATA_BAD;
 111                 }
 112                 return self::METADATA_GOOD;
 113         }
 114
 115         /**
 116          * @param $image File
 117          * @return array|bool
 118          */
 119         function formatMetadata( $image ) {
 120                 $metadata = $image->getMetadata();
 121                 if ( $metadata === self::OLD_BROKEN_FILE ||
 122                         $metadata === self::BROKEN_FILE ||
 123                         $this->isMetadataValid( $image, $metadata ) === self::METADATA_BAD )
 124                 {
 125                         // So we don't try and display metadata from PagedTiffHandler
 126                         // for example when using InstantCommons.
 127                         return false;
 128                 }
 129
 130                 $exif = unserialize( $metadata );
 131                 if ( !$exif ) {
 132                         return false;
 133                 }
 134                 unset( $exif['MEDIAWIKI_EXIF_VERSION'] );
 135                 if ( count( $exif ) == 0 ) {
 136                         return false;
 137                 }
 138                 return $this->formatMetadataHelper( $exif );
 139         }
 140
 141         function getMetadataType( $image ) {
 142                 return 'exif';
 143         }
 144
 145         /**
 146          * Wrapper for base classes ImageHandler::getImageSize() that checks for
 147          * rotation reported from metadata and swaps the sizes to match.
 148          *
 149          * @param File $image
 150          * @param string $path
 151          * @return array
 152          */
 153         function getImageSize( $image, $path ) {
 154                 global $wgEnableAutoRotation;
 155                 $gis = parent::getImageSize( $image, $path );
 156
 157                 // Don't just call $image->getMetadata(); FSFile::getPropsFromPath() calls us with a bogus object.
 158                 // This may mean we read EXIF data twice on initial upload.
 159                 if ( $wgEnableAutoRotation ) {
 160                         $meta = $this->getMetadata( $image, $path );
 161                         $rotation = $this->getRotationForExif( $meta );
 162                 } else {
 163                         $rotation = 0;
 164                 }
 165
 166                 if ( $rotation == 90 || $rotation == 270 ) {
 167                         $width = $gis[0];
 168                         $gis[0] = $gis[1];
 169                         $gis[1] = $width;
 170                 }
 171                 return $gis;
 172         }
 173
 174         /**
 175          * On supporting image formats, try to read out the low-level orientation
 176          * of the file and return the angle that the file needs to be rotated to
 177          * be viewed.
 178          *
 179          * This information is only useful when manipulating the original file;
 180          * the width and height we normally work with is logical, and will match
 181          * any produced output views.
 182          *
 183          * @param $file File
 184          * @return int 0, 90, 180 or 270
 185          */
 186         public function getRotation( $file ) {
 187                 global $wgEnableAutoRotation;
 188                 if ( !$wgEnableAutoRotation ) {
 189                         return 0;
 190                 }
 191
 192                 $data = $file->getMetadata();
 193                 return $this->getRotationForExif( $data );
 194         }
 195
 196         /**
 197          * Given a chunk of serialized Exif metadata, return the orientation as
 198          * degrees of rotation.
 199          *
 200          * @param string $data
 201          * @return int 0, 90, 180 or 270
 202          * @todo FIXME orientation can include flipping as well; see if this is an
 203          * issue!
 204          */
 205         protected function getRotationForExif( $data ) {
 206                 if ( !$data ) {
 207                         return 0;
 208                 }
 209                 wfSuppressWarnings();
 210                 $data = unserialize( $data );
 211                 wfRestoreWarnings();
 212                 if ( isset( $data['Orientation'] ) ) {
 213                         # See http://sylvana.net/jpegcrop/exif_orientation.html
 214                         switch ( $data['Orientation'] ) {
 215                                 case 8:
 216                                         return 90;
 217                                 case 3:
 218                                         return 180;
 219                                 case 6:
 220                                         return 270;
 221                                 default:
 222                                         return 0;
 223                         }
 224                 }
 225                 return 0;
 226         }
 227 }