includes/media/ExifBitmap.php

   1 <?php
   2 /**
   3  * @file
   4  * @ingroup Media
   5  */
   6
   7 /**
   8  * Stuff specific to JPEG and (built-in) TIFF handler.
   9  * All metadata related, since both JPEG and TIFF support Exif.
  10  *
  11  * @ingroup Media
  12  */
  13 class ExifBitmapHandler extends BitmapHandler {
  14
  15         const BROKEN_FILE = '-1'; // error extracting metadata
  16         const OLD_BROKEN_FILE = '0'; // outdated error extracting metadata.
  17
  18         function convertMetadataVersion( $metadata, $version = 1 ) {
  19                 // basically flattens arrays.
  20                 $version = explode(';', $version, 2);
  21                 $version = intval($version[0]);
  22                 if ( $version < 1 || $version >= 2 ) {
  23                         return $metadata;
  24                 }
  25
  26                 $avoidHtml = true;
  27
  28                 if ( !is_array( $metadata ) ) {
  29                         $metadata = unserialize( $metadata );
  30                 }
  31                 if ( !isset( $metadata['MEDIAWIKI_EXIF_VERSION'] ) || $metadata['MEDIAWIKI_EXIF_VERSION'] != 2 ) {
  32                         return $metadata;
  33                 }
  34
  35                 // Treat Software as a special case because in can contain
  36                 // an array of (SoftwareName, Version).
  37                 if (isset( $metadata['Software'] )
  38                         && is_array( $metadata['Software'] )
  39                         && is_array( $metadata['Software'][0])
  40                         && isset( $metadata['Software'][0][0] )
  41                         && isset( $metadata['Software'][0][1])
  42                  ) {
  43                         $metadata['Software'] = $metadata['Software'][0][0] . ' (Version '
  44                                 . $metadata['Software'][0][1] . ')';
  45                 }
  46
  47                 // ContactInfo also has to be dealt with specially
  48                 if ( isset( $metadata['Contact'] ) ) {
  49                         $metadata['Contact'] =
  50                                 FormatMetadata::collapseContactInfo(
  51                                         $metadata['Contact'] );
  52                 }
  53
  54                 foreach ( $metadata as &$val ) {
  55                         if ( is_array( $val ) ) {
  56                                 $val = FormatMetadata::flattenArray( $val, 'ul', $avoidHtml );
  57                         }
  58                 }
  59                 $metadata['MEDIAWIKI_EXIF_VERSION'] = 1;
  60                 return $metadata;
  61         }
  62
  63         function isMetadataValid( $image, $metadata ) {
  64                 global $wgShowEXIF;
  65                 if ( !$wgShowEXIF ) {
  66                         # Metadata disabled and so an empty field is expected
  67                         return self::METADATA_GOOD;
  68                 }
  69                 if ( $metadata === self::OLD_BROKEN_FILE ) {
  70                         # Old special value indicating that there is no EXIF data in the file.
  71                         # or that there was an error well extracting the metadata.
  72                         wfDebug( __METHOD__ . ": back-compat version\n");
  73                         return self::METADATA_COMPATIBLE;
  74                 }
  75                 if ( $metadata === self::BROKEN_FILE ) {
  76                         return self::METADATA_GOOD;
  77                 }
  78                 wfSuppressWarnings();
  79                 $exif = unserialize( $metadata );
  80                 wfRestoreWarnings();
  81                 if ( !isset( $exif['MEDIAWIKI_EXIF_VERSION'] ) ||
  82                         $exif['MEDIAWIKI_EXIF_VERSION'] != Exif::version() )
  83                 {
  84                         if ( isset( $exif['MEDIAWIKI_EXIF_VERSION'] ) &&
  85                                 $exif['MEDIAWIKI_EXIF_VERSION'] == 1 )
  86                         {
  87                                 //back-compatible but old
  88                                 wfDebug( __METHOD__.": back-compat version\n" );
  89                                 return self::METADATA_COMPATIBLE;
  90                         }
  91                         # Wrong (non-compatible) version
  92                         wfDebug( __METHOD__.": wrong version\n" );
  93                         return self::METADATA_BAD;
  94                 }
  95                 return self::METADATA_GOOD;
  96         }
  97
  98         /**
  99          * @param $image File
 100          * @return array|bool
 101          */
 102         function formatMetadata( $image ) {
 103                 $metadata = $image->getMetadata();
 104                 if ( $metadata === self::OLD_BROKEN_FILE ||
 105                         $metadata === self::BROKEN_FILE ||
 106                         $this->isMetadataValid( $image, $metadata ) === self::METADATA_BAD )
 107                 {
 108                         // So we don't try and display metadata from PagedTiffHandler
 109                         // for example when using InstantCommons.
 110                         return false;
 111                 }
 112
 113                 $exif = unserialize( $metadata );
 114                 if ( !$exif ) {
 115                         return false;
 116                 }
 117                 unset( $exif['MEDIAWIKI_EXIF_VERSION'] );
 118                 if ( count( $exif ) == 0 ) {
 119                         return false;
 120                 }
 121                 return $this->formatMetadataHelper( $exif );
 122         }
 123
 124         function getMetadataType( $image ) {
 125                 return 'exif';
 126         }
 127
 128         /**
 129          * Wrapper for base classes ImageHandler::getImageSize() that checks for
 130          * rotation reported from metadata and swaps the sizes to match.
 131          *
 132          * @param File $image
 133          * @param string $path
 134          * @return array
 135          */
 136         function getImageSize( $image, $path ) {
 137                 $gis = parent::getImageSize( $image, $path );
 138
 139                 // Don't just call $image->getMetadata(); File::getPropsFromPath() calls us with a bogus object.
 140                 // This may mean we read EXIF data twice on initial upload.
 141                 $meta = $this->getMetadata( $image, $path );
 142                 $rotation = $this->getRotationForExif( $meta );
 143
 144                 if ($rotation == 90 || $rotation == 270) {
 145                         $width = $gis[0];
 146                         $gis[0] = $gis[1];
 147                         $gis[1] = $width;
 148                 }
 149                 return $gis;
 150         }
 151
 152         /**
 153          * On supporting image formats, try to read out the low-level orientation
 154          * of the file and return the angle that the file needs to be rotated to
 155          * be viewed.
 156          *
 157          * This information is only useful when manipulating the original file;
 158          * the width and height we normally work with is logical, and will match
 159          * any produced output views.
 160          *
 161          * @param $file File
 162          * @return int 0, 90, 180 or 270
 163          */
 164         public function getRotation( $file ) {
 165                 global $wgEnableAutoRotation;
 166                 if ( !$wgEnableAutoRotation ) {
 167                         return 0;
 168                 }
 169
 170                 $data = $file->getMetadata();
 171                 return $this->getRotationForExif( $data );
 172         }
 173
 174         /**
 175          * Given a chunk of serialized Exif metadata, return the orientation as
 176          * degrees of rotation.
 177          *
 178          * @param string $data
 179          * @return int 0, 90, 180 or 270
 180          * @fixme orientation can include flipping as well; see if this is an issue!
 181          */
 182         protected function getRotationForExif( $data ) {
 183                 if ( !$data ) {
 184                         return 0;
 185                 }
 186                 wfSuppressWarnings();
 187                 $data = unserialize( $data );
 188                 wfRestoreWarnings();
 189                 if ( isset( $data['Orientation'] ) ) {
 190                         # See http://sylvana.net/jpegcrop/exif_orientation.html
 191                         switch ( $data['Orientation'] ) {
 192                                 case 8:
 193                                         return 90;
 194                                 case 3:
 195                                         return 180;
 196                                 case 6:
 197                                         return 270;
 198                                 default:
 199                                         return 0;
 200                         }
 201                 }
 202                 return 0;
 203         }
 204 }
 205