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  33         const OLD_BROKEN_FILE = '0'; // outdated error extracting metadata.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                 $formatter = new FormatMetadata;
  65
  66                 // ContactInfo also has to be dealt with specially
  67                 if ( isset( $metadata['Contact'] ) ) {
  68                         $metadata['Contact'] =
  69                                 $formatter->collapseContactInfo(
  70                                         $metadata['Contact'] );
  71                 }
  72
  73                 foreach ( $metadata as &$val ) {
  74                         if ( is_array( $val ) ) {
  75                                 $val = $formatter->flattenArrayReal( $val, 'ul', $avoidHtml );
  76                         }
  77                 }
  78                 $metadata['MEDIAWIKI_EXIF_VERSION'] = 1;
  79                 return $metadata;
  80         }
  81
  82         function isMetadataValid( $image, $metadata ) {
  83                 global $wgShowEXIF;
  84                 if ( !$wgShowEXIF ) {
  85                         # Metadata disabled and so an empty field is expected
  86                         return self::METADATA_GOOD;
  87                 }
  88                 if ( $metadata === self::OLD_BROKEN_FILE ) {
  89                         # Old special value indicating that there is no Exif data in the file.
  90                         # or that there was an error well extracting the metadata.
  91                         wfDebug( __METHOD__ . ": back-compat version\n" );
  92                         return self::METADATA_COMPATIBLE;
  93                 }
  94                 if ( $metadata === self::BROKEN_FILE ) {
  95                         return self::METADATA_GOOD;
  96                 }
  97                 wfSuppressWarnings();
  98                 $exif = unserialize( $metadata );
  99                 wfRestoreWarnings();
 100                 if ( !isset( $exif['MEDIAWIKI_EXIF_VERSION'] ) ||
 101                         $exif['MEDIAWIKI_EXIF_VERSION'] != Exif::version() )
 102                 {
 103                         if ( isset( $exif['MEDIAWIKI_EXIF_VERSION'] ) &&
 104                                 $exif['MEDIAWIKI_EXIF_VERSION'] == 1 )
 105                         {
 106                                 //back-compatible but old
 107                                 wfDebug( __METHOD__ . ": back-compat version\n" );
 108                                 return self::METADATA_COMPATIBLE;
 109                         }
 110                         # Wrong (non-compatible) version
 111                         wfDebug( __METHOD__ . ": wrong version\n" );
 112                         return self::METADATA_BAD;
 113                 }
 114                 return self::METADATA_GOOD;
 115         }
 116
 117         /**
 118          * @param $image File
 119          * @return array|bool
 120          */
 121         function formatMetadata( $image ) {
 122                 $meta = $this->getCommonMetaArray( $image );
 123                 if ( count( $meta ) === 0 ) {
 124                         return false;
 125                 }
 126
 127                 return $this->formatMetadataHelper( $meta );
 128         }
 129
 130         public function getCommonMetaArray( File $file ) {
 131                 $metadata = $file->getMetadata();
 132                 if ( $metadata === self::OLD_BROKEN_FILE ||
 133                         $metadata === self::BROKEN_FILE ||
 134                         $this->isMetadataValid( $file, $metadata ) === self::METADATA_BAD )
 135                 {
 136                         // So we don't try and display metadata from PagedTiffHandler
 137                         // for example when using InstantCommons.
 138                         return array();
 139                 }
 140
 141                 $exif = unserialize( $metadata );
 142                 if ( !$exif ) {
 143                         return array();
 144                 }
 145                 unset( $exif['MEDIAWIKI_EXIF_VERSION'] );
 146
 147                 return $exif;
 148         }
 149
 150         function getMetadataType( $image ) {
 151                 return 'exif';
 152         }
 153
 154         /**
 155          * Wrapper for base classes ImageHandler::getImageSize() that checks for
 156          * rotation reported from metadata and swaps the sizes to match.
 157          *
 158          * @param File $image
 159          * @param string $path
 160          * @return array
 161          */
 162         function getImageSize( $image, $path ) {
 163                 global $wgEnableAutoRotation;
 164                 $gis = parent::getImageSize( $image, $path );
 165
 166                 // Don't just call $image->getMetadata(); FSFile::getPropsFromPath() calls us with a bogus object.
 167                 // This may mean we read EXIF data twice on initial upload.
 168                 if ( $wgEnableAutoRotation ) {
 169                         $meta = $this->getMetadata( $image, $path );
 170                         $rotation = $this->getRotationForExif( $meta );
 171                 } else {
 172                         $rotation = 0;
 173                 }
 174
 175                 if ( $rotation == 90 || $rotation == 270 ) {
 176                         $width = $gis[0];
 177                         $gis[0] = $gis[1];
 178                         $gis[1] = $width;
 179                 }
 180                 return $gis;
 181         }
 182
 183         /**
 184          * On supporting image formats, try to read out the low-level orientation
 185          * of the file and return the angle that the file needs to be rotated to
 186          * be viewed.
 187          *
 188          * This information is only useful when manipulating the original file;
 189          * the width and height we normally work with is logical, and will match
 190          * any produced output views.
 191          *
 192          * @param $file File
 193          * @return int 0, 90, 180 or 270
 194          */
 195         public function getRotation( $file ) {
 196                 global $wgEnableAutoRotation;
 197                 if ( !$wgEnableAutoRotation ) {
 198                         return 0;
 199                 }
 200
 201                 $data = $file->getMetadata();
 202                 return $this->getRotationForExif( $data );
 203         }
 204
 205         /**
 206          * Given a chunk of serialized Exif metadata, return the orientation as
 207          * degrees of rotation.
 208          *
 209          * @param string $data
 210          * @return int 0, 90, 180 or 270
 211          * @todo FIXME orientation can include flipping as well; see if this is an
 212          * issue!
 213          */
 214         protected function getRotationForExif( $data ) {
 215                 if ( !$data ) {
 216                         return 0;
 217                 }
 218                 wfSuppressWarnings();
 219                 $data = unserialize( $data );
 220                 wfRestoreWarnings();
 221                 if ( isset( $data['Orientation'] ) ) {
 222                         # See http://sylvana.net/jpegcrop/exif_orientation.html
 223                         switch ( $data['Orientation'] ) {
 224                                 case 8:
 225                                         return 90;
 226                                 case 3:
 227                                         return 180;
 228                                 case 6:
 229                                         return 270;
 230                                 default:
 231                                         return 0;
 232                         }
 233                 }
 234                 return 0;
 235         }
 236 }