includes/media/Bitmap.php

   1 <?php
   2 /**
   3  * Generic handler for bitmap images
   4  *
   5  * @file
   6  * @ingroup Media
   7  */
   8
   9 /**
  10  * Generic handler for bitmap images
  11  *
  12  * @ingroup Media
  13  */
  14 class BitmapHandler extends ImageHandler {
  15         function normaliseParams( $image, &$params ) {
  16                 global $wgMaxImageArea;
  17                 if ( !parent::normaliseParams( $image, $params ) ) {
  18                         return false;
  19                 }
  20
  21                 $mimeType = $image->getMimeType();
  22                 $srcWidth = $image->getWidth( $params['page'] );
  23                 $srcHeight = $image->getHeight( $params['page'] );
  24
  25                 if ( $this->canRotate() ) {
  26                         $rotation = $this->getRotation( $image );
  27                         if ( $rotation == 90 || $rotation == 270 ) {
  28                                 wfDebug( __METHOD__ . ": Swapping width and height because the file will be rotation $rotation degrees\n" );
  29
  30                                 $width = $params['width'];
  31                                 $params['width'] = $params['height'];
  32                                 $params['height'] = $width;
  33                         }
  34                 }
  35
  36                 # Don't make an image bigger than the source
  37                 $params['physicalWidth'] = $params['width'];
  38                 $params['physicalHeight'] = $params['height'];
  39
  40                 if ( $params['physicalWidth'] >= $srcWidth ) {
  41                         $params['physicalWidth'] = $srcWidth;
  42                         $params['physicalHeight'] = $srcHeight;
  43                         # Skip scaling limit checks if no scaling is required
  44                         if ( !$image->mustRender() )
  45                                 return true;
  46                 }
  47
  48                 # Don't thumbnail an image so big that it will fill hard drives and send servers into swap
  49                 # JPEG has the handy property of allowing thumbnailing without full decompression, so we make
  50                 # an exception for it.
  51                 # FIXME: This actually only applies to ImageMagick
  52                 if ( $mimeType !== 'image/jpeg' &&
  53                         $srcWidth * $srcHeight > $wgMaxImageArea )
  54                 {
  55                         return false;
  56                 }
  57
  58                 return true;
  59         }
  60
  61
  62         // Function that returns the number of pixels to be thumbnailed.
  63         // Intended for animated GIFs to multiply by the number of frames.
  64         function getImageArea( $image, $width, $height ) {
  65                 return $width * $height;
  66         }
  67
  68         function doTransform( $image, $dstPath, $dstUrl, $params, $flags = 0 ) {
  69                 global $wgCustomConvertCommand;
  70
  71                 if ( !$this->normaliseParams( $image, $params ) ) {
  72                         return new TransformParameterError( $params );
  73                 }
  74                 # Create a parameter array to pass to the scaler
  75                 $scalerParams = array(
  76                         # The size to which the image will be resized
  77                         'physicalWidth' => $params['physicalWidth'],
  78                         'physicalHeight' => $params['physicalHeight'],
  79                         'physicalDimensions' => "{$params['physicalWidth']}x{$params['physicalHeight']}",
  80                         # The size of the image on the page
  81                         'clientWidth' => $params['width'],
  82                         'clientHeight' => $params['height'],
  83                         # Comment as will be added to the EXIF of the thumbnail
  84                         'comment' => isset( $params['descriptionUrl'] ) ?
  85                                 "File source: {$params['descriptionUrl']}" : '',
  86                         # Properties of the original image
  87                         'srcWidth' => $image->getWidth(),
  88                         'srcHeight' => $image->getHeight(),
  89                         'mimeType' => $image->getMimeType(),
  90                         'srcPath' => $image->getPath(),
  91                         'dstPath' => $dstPath,
  92                 );
  93
  94                 wfDebug( __METHOD__ . ": creating {$scalerParams['physicalDimensions']} thumbnail at $dstPath\n" );
  95
  96                 if ( !$image->mustRender() &&
  97                                 $scalerParams['physicalWidth'] == $scalerParams['srcWidth']
  98                                 && $scalerParams['physicalHeight'] == $scalerParams['srcHeight'] ) {
  99
 100                         # normaliseParams (or the user) wants us to return the unscaled image
 101                         wfDebug( __METHOD__ . ": returning unscaled image\n" );
 102                         return $this->getClientScalingThumbnailImage( $image, $scalerParams );
 103                 }
 104
 105                 # Determine scaler type
 106                 $scaler = $this->getScalerType( $dstPath );
 107                 wfDebug( __METHOD__ . ": scaler $scaler\n" );
 108
 109                 if ( $scaler == 'client' ) {
 110                         # Client-side image scaling, use the source URL
 111                         # Using the destination URL in a TRANSFORM_LATER request would be incorrect
 112                         return $this->getClientScalingThumbnailImage( $image, $scalerParams );
 113                 }
 114
 115                 if ( $flags & self::TRANSFORM_LATER ) {
 116                         wfDebug( __METHOD__ . ": Transforming later per flags.\n" );
 117                         return new ThumbnailImage( $image, $dstUrl, $scalerParams['clientWidth'],
 118                                 $scalerParams['clientHeight'], $dstPath );
 119                 }
 120
 121                 # Try to make a target path for the thumbnail
 122                 if ( !wfMkdirParents( dirname( $dstPath ) ) ) {
 123                         wfDebug( __METHOD__ . ": Unable to create thumbnail destination directory, falling back to client scaling\n" );
 124                         return $this->getClientScalingThumbnailImage( $image, $scalerParams );
 125                 }
 126
 127                 switch ( $scaler ) {
 128                         case 'im':
 129                                 $err = $this->transformImageMagick( $image, $scalerParams );
 130                                 break;
 131                         case 'custom':
 132                                 $err = $this->transformCustom( $image, $scalerParams );
 133                                 break;
 134                         case 'gd':
 135                         default:
 136                                 $err = $this->transformGd( $image, $scalerParams );
 137                                 break;
 138                 }
 139
 140                 # Remove the file if a zero-byte thumbnail was created, or if there was an error
 141                 $removed = $this->removeBadFile( $dstPath, (bool)$err );
 142                 if ( $err ) {
 143                         # transform returned MediaTransforError
 144                         return $err;
 145                 } elseif ( $removed ) {
 146                         # Thumbnail was zero-byte and had to be removed
 147                         return new MediaTransformError( 'thumbnail_error',
 148                                 $scalerParams['clientWidth'], $scalerParams['clientHeight'] );
 149                 } else {
 150                         return new ThumbnailImage( $image, $dstUrl, $scalerParams['clientWidth'],
 151                                 $scalerParams['clientHeight'], $dstPath );
 152                 }
 153         }
 154
 155         /**
 156          * Returns which scaler type should be used. Creates parent directories
 157          * for $dstPath and returns 'client' on error
 158          *
 159          * @return string client,im,custom,gd
 160          */
 161         protected function getScalerType( $dstPath, $checkDstPath = true ) {
 162                 global $wgUseImageResize, $wgUseImageMagick, $wgCustomConvertCommand;
 163
 164                 if ( !$dstPath && $checkDstPath ) {
 165                         # No output path available, client side scaling only
 166                         $scaler = 'client';
 167                 } elseif ( !$wgUseImageResize ) {
 168                         $scaler = 'client';
 169                 } elseif ( $wgUseImageMagick ) {
 170                         $scaler = 'im';
 171                 } elseif ( $wgCustomConvertCommand ) {
 172                         $scaler = 'custom';
 173                 } elseif ( function_exists( 'imagecreatetruecolor' ) ) {
 174                         $scaler = 'gd';
 175                 } else {
 176                         $scaler = 'client';
 177                 }
 178
 179                 if ( $scaler != 'client' && $dstPath ) {
 180                         if ( !wfMkdirParents( dirname( $dstPath ) ) ) {
 181                                 # Unable to create a path for the thumbnail
 182                                 return 'client';
 183                         }
 184                 }
 185                 return $scaler;
 186         }
 187
 188         /**
 189          * Get a ThumbnailImage that respresents an image that will be scaled
 190          * client side
 191          *
 192          * @param $image File File associated with this thumbnail
 193          * @param $params array Array with scaler params
 194          * @return ThumbnailImage
 195          */
 196         protected function getClientScalingThumbnailImage( $image, $params ) {
 197                 return new ThumbnailImage( $image, $image->getURL(),
 198                                 $params['clientWidth'], $params['clientHeight'], $params['srcPath'] );
 199         }
 200
 201         /**
 202          * Transform an image using ImageMagick
 203          *
 204          * @param $image File File associated with this thumbnail
 205          * @param $params array Array with scaler params
 206          *
 207          * @return MediaTransformError Error object if error occured, false (=no error) otherwise
 208          */
 209         protected function transformImageMagick( $image, $params ) {
 210                 # use ImageMagick
 211                 global $wgSharpenReductionThreshold, $wgSharpenParameter,
 212                         $wgMaxAnimatedGifArea,
 213                         $wgImageMagickTempDir, $wgImageMagickConvertCommand;
 214
 215                 $quality = '';
 216                 $sharpen = '';
 217                 $scene = false;
 218                 $animation_pre = '';
 219                 $animation_post = '';
 220                 $decoderHint = '';
 221                 if ( $params['mimeType'] == 'image/jpeg' ) {
 222                         $quality = "-quality 80"; // 80%
 223                         # Sharpening, see bug 6193
 224                         if ( ( $params['physicalWidth'] + $params['physicalHeight'] )
 225                                         / ( $params['srcWidth'] + $params['srcHeight'] )
 226                                         < $wgSharpenReductionThreshold ) {
 227                                 $sharpen = "-sharpen " . wfEscapeShellArg( $wgSharpenParameter );
 228                         }
 229                         // JPEG decoder hint to reduce memory, available since IM 6.5.6-2
 230                         $decoderHint = "-define jpeg:size={$params['physicalDimensions']}";
 231
 232                 } elseif ( $params['mimeType'] == 'image/png' ) {
 233                         $quality = "-quality 95"; // zlib 9, adaptive filtering
 234
 235                 } elseif ( $params['mimeType'] == 'image/gif' ) {
 236                         if ( $this->getImageArea( $image, $params['srcWidth'],
 237                                         $params['srcHeight'] ) > $wgMaxAnimatedGifArea ) {
 238                                 // Extract initial frame only; we're so big it'll
 239                                 // be a total drag. :P
 240                                 $scene = 0;
 241
 242                         } elseif ( $this->isAnimatedImage( $image ) ) {
 243                                 // Coalesce is needed to scale animated GIFs properly (bug 1017).
 244                                 $animation_pre = '-coalesce';
 245                                 // We optimize the output, but -optimize is broken,
 246                                 // use optimizeTransparency instead (bug 11822)
 247                                 if ( version_compare( $this->getMagickVersion(), "6.3.5" ) >= 0 ) {
 248                                         $animation_post = '-fuzz 5% -layers optimizeTransparency +map';
 249                                 }
 250                         }
 251                 }
 252
 253                 // Use one thread only, to avoid deadlock bugs on OOM
 254                 $env = array( 'OMP_NUM_THREADS' => 1 );
 255                 if ( strval( $wgImageMagickTempDir ) !== '' ) {
 256                         $env['MAGICK_TMPDIR'] = $wgImageMagickTempDir;
 257                 }
 258
 259                 $cmd  =
 260                         wfEscapeShellArg( $wgImageMagickConvertCommand ) .
 261                         // Specify white background color, will be used for transparent images
 262                         // in Internet Explorer/Windows instead of default black.
 263                         " {$quality} -background white" .
 264                         " {$decoderHint} " .
 265                         wfEscapeShellArg( $this->escapeMagickInput( $params['srcPath'], $scene ) ) .
 266                         " {$animation_pre}" .
 267                         // For the -thumbnail option a "!" is needed to force exact size,
 268                         // or ImageMagick may decide your ratio is wrong and slice off
 269                         // a pixel.
 270                         " -thumbnail " . wfEscapeShellArg( "{$params['physicalDimensions']}!" ) .
 271                         // Add the source url as a comment to the thumb, but don't add the flag if there's no comment
 272                         ( $params['comment'] !== ''
 273                                 ? " -set comment " . wfEscapeShellArg( $this->escapeMagickProperty( $params['comment'] ) )
 274                                 : '' ) .
 275                         " -depth 8 $sharpen -auto-orient" .
 276                         " {$animation_post} " .
 277                         wfEscapeShellArg( $this->escapeMagickOutput( $params['dstPath'] ) ) . " 2>&1";
 278
 279                 wfDebug( __METHOD__ . ": running ImageMagick: $cmd\n" );
 280                 wfProfileIn( 'convert' );
 281                 $retval = 0;
 282                 $err = wfShellExec( $cmd, $retval, $env );
 283                 wfProfileOut( 'convert' );
 284
 285                 if ( $retval !== 0 ) {
 286                         $this->logErrorForExternalProcess( $retval, $err, $cmd );
 287                         return $this->getMediaTransformError( $params, $err );
 288                 }
 289
 290                 return false; # No error
 291         }
 292
 293         /**
 294          * Transform an image using a custom command
 295          *
 296          * @param $image File File associated with this thumbnail
 297          * @param $params array Array with scaler params
 298          *
 299          * @return MediaTransformError Error object if error occured, false (=no error) otherwise
 300          */
 301         protected function transformCustom( $image, $params ) {
 302                 # Use a custom convert command
 303                 global $wgCustomConvertCommand;
 304
 305                 # Variables: %s %d %w %h
 306                 $src = wfEscapeShellArg( $params['srcPath'] );
 307                 $dst = wfEscapeShellArg( $params['dstPath'] );
 308                 $cmd = $wgCustomConvertCommand;
 309                 $cmd = str_replace( '%s', $src, str_replace( '%d', $dst, $cmd ) ); # Filenames
 310                 $cmd = str_replace( '%h', $params['physicalHeight'],
 311                         str_replace( '%w', $params['physicalWidth'], $cmd ) ); # Size
 312                 wfDebug( __METHOD__ . ": Running custom convert command $cmd\n" );
 313                 wfProfileIn( 'convert' );
 314                 $retval = 0;
 315                 $err = wfShellExec( $cmd, $retval );
 316                 wfProfileOut( 'convert' );
 317
 318                 if ( $retval !== 0 ) {
 319                         $this->logErrorForExternalProcess( $retval, $err, $cmd );
 320                         return $this->getMediaTransformError( $params, $err );
 321                 }
 322                 return false; # No error
 323         }
 324
 325         /**
 326          * Log an error that occured in an external process
 327          *
 328          * @param $retval int
 329          * @param $err int
 330          * @param $cmd string
 331          */
 332         protected function logErrorForExternalProcess( $retval, $err, $cmd ) {
 333                 wfDebugLog( 'thumbnail',
 334                         sprintf( 'thumbnail failed on %s: error %d "%s" from "%s"',
 335                                         wfHostname(), $retval, trim( $err ), $cmd ) );
 336         }
 337         /**
 338          * Get a MediaTransformError with error 'thumbnail_error'
 339          *
 340          * @param $params array Parameter array as passed to the transform* functions
 341          * @param $errMsg string Error message
 342          * @return MediaTransformError
 343          */
 344         protected function getMediaTransformError( $params, $errMsg ) {
 345                 return new MediaTransformError( 'thumbnail_error', $params['clientWidth'],
 346                                         $params['clientHeight'], $errMsg );
 347         }
 348
 349         /**
 350          * Transform an image using the built in GD library
 351          *
 352          * @param $image File File associated with this thumbnail
 353          * @param $params array Array with scaler params
 354          *
 355          * @return MediaTransformError Error object if error occured, false (=no error) otherwise
 356          */
 357         protected function transformGd( $image, $params ) {
 358                 # Use PHP's builtin GD library functions.
 359                 #
 360                 # First find out what kind of file this is, and select the correct
 361                 # input routine for this.
 362
 363                 $typemap = array(
 364                         'image/gif'          => array( 'imagecreatefromgif',  'palette',   'imagegif'  ),
 365                         'image/jpeg'         => array( 'imagecreatefromjpeg', 'truecolor', array( __CLASS__, 'imageJpegWrapper' ) ),
 366                         'image/png'          => array( 'imagecreatefrompng',  'bits',      'imagepng'  ),
 367                         'image/vnd.wap.wbmp' => array( 'imagecreatefromwbmp', 'palette',   'imagewbmp'  ),
 368                         'image/xbm'          => array( 'imagecreatefromxbm',  'palette',   'imagexbm'  ),
 369                 );
 370                 if ( !isset( $typemap[$params['mimeType']] ) ) {
 371                         $err = 'Image type not supported';
 372                         wfDebug( "$err\n" );
 373                         $errMsg = wfMsg ( 'thumbnail_image-type' );
 374                         return $this->getMediaTransformError( $params, $errMsg );
 375                 }
 376                 list( $loader, $colorStyle, $saveType ) = $typemap[$params['mimeType']];
 377
 378                 if ( !function_exists( $loader ) ) {
 379                         $err = "Incomplete GD library configuration: missing function $loader";
 380                         wfDebug( "$err\n" );
 381                         $errMsg = wfMsg ( 'thumbnail_gd-library', $loader );
 382                         return $this->getMediaTransformError( $params, $errMsg );
 383                 }
 384
 385                 if ( !file_exists( $params['srcPath'] ) ) {
 386                         $err = "File seems to be missing: {$params['srcPath']}";
 387                         wfDebug( "$err\n" );
 388                         $errMsg = wfMsg ( 'thumbnail_image-missing', $params['srcPath'] );
 389                         return $this->getMediaTransformError( $params, $errMsg );
 390                 }
 391
 392                 $src_image = call_user_func( $loader, $params['srcPath'] );
 393                 $rotation = $this->getRotation( $image );
 394                 if ( $rotation == 90 || $rotation == 270 ) {
 395                         # We'll resize before rotation, so swap the dimensions again
 396                         $width = $params['physicalHeight'];
 397                         $height = $params['physicalWidth'];
 398                 } else {
 399                         $width = $params['physicalWidth'];
 400                         $height = $params['physicalHeight'];
 401                 }
 402                 $dst_image = imagecreatetruecolor( $width, $height );
 403
 404                 // Initialise the destination image to transparent instead of
 405                 // the default solid black, to support PNG and GIF transparency nicely
 406                 $background = imagecolorallocate( $dst_image, 0, 0, 0 );
 407                 imagecolortransparent( $dst_image, $background );
 408                 imagealphablending( $dst_image, false );
 409
 410                 if ( $colorStyle == 'palette' ) {
 411                         // Don't resample for paletted GIF images.
 412                         // It may just uglify them, and completely breaks transparency.
 413                         imagecopyresized( $dst_image, $src_image,
 414                                 0, 0, 0, 0,
 415                                 $width, $height,
 416                                 imagesx( $src_image ), imagesy( $src_image ) );
 417                 } else {
 418                         imagecopyresampled( $dst_image, $src_image,
 419                                 0, 0, 0, 0,
 420                                 $width, $height,
 421                                 imagesx( $src_image ), imagesy( $src_image ) );
 422                 }
 423
 424                 if ( $rotation % 360 != 0 && $rotation % 90 == 0 ) {
 425                         $rot_image = imagerotate( $dst_image, $rotation, 0 );
 426                         imagedestroy( $dst_image );
 427                         $dst_image = $rot_image;
 428                 }
 429
 430                 imagesavealpha( $dst_image, true );
 431
 432                 call_user_func( $saveType, $dst_image, $params['dstPath'] );
 433                 imagedestroy( $dst_image );
 434                 imagedestroy( $src_image );
 435
 436                 return false; # No error
 437         }
 438
 439         /**
 440          * Escape a string for ImageMagick's property input (e.g. -set -comment)
 441          * See InterpretImageProperties() in magick/property.c
 442          */
 443         function escapeMagickProperty( $s ) {
 444                 // Double the backslashes
 445                 $s = str_replace( '\\', '\\\\', $s );
 446                 // Double the percents
 447                 $s = str_replace( '%', '%%', $s );
 448                 // Escape initial - or @
 449                 if ( strlen( $s ) > 0 && ( $s[0] === '-' || $s[0] === '@' ) ) {
 450                         $s = '\\' . $s;
 451                 }
 452                 return $s;
 453         }
 454
 455         /**
 456          * Escape a string for ImageMagick's input filenames. See ExpandFilenames()
 457          * and GetPathComponent() in magick/utility.c.
 458          *
 459          * This won't work with an initial ~ or @, so input files should be prefixed
 460          * with the directory name.
 461          *
 462          * Glob character unescaping is broken in ImageMagick before 6.6.1-5, but
 463          * it's broken in a way that doesn't involve trying to convert every file
 464          * in a directory, so we're better off escaping and waiting for the bugfix
 465          * to filter down to users.
 466          *
 467          * @param $path string The file path
 468          * @param $scene string The scene specification, or false if there is none
 469          */
 470         function escapeMagickInput( $path, $scene = false ) {
 471                 # Die on initial metacharacters (caller should prepend path)
 472                 $firstChar = substr( $path, 0, 1 );
 473                 if ( $firstChar === '~' || $firstChar === '@' ) {
 474                         throw new MWException( __METHOD__ . ': cannot escape this path name' );
 475                 }
 476
 477                 # Escape glob chars
 478                 $path = preg_replace( '/[*?\[\]{}]/', '\\\\\0', $path );
 479
 480                 return $this->escapeMagickPath( $path, $scene );
 481         }
 482
 483         /**
 484          * Escape a string for ImageMagick's output filename. See
 485          * InterpretImageFilename() in magick/image.c.
 486          */
 487         function escapeMagickOutput( $path, $scene = false ) {
 488                 $path = str_replace( '%', '%%', $path );
 489                 return $this->escapeMagickPath( $path, $scene );
 490         }
 491
 492         /**
 493          * Armour a string against ImageMagick's GetPathComponent(). This is a
 494          * helper function for escapeMagickInput() and escapeMagickOutput().
 495          *
 496          * @param $path string The file path
 497          * @param $scene string The scene specification, or false if there is none
 498          */
 499         protected function escapeMagickPath( $path, $scene = false ) {
 500                 # Die on format specifiers (other than drive letters). The regex is
 501                 # meant to match all the formats you get from "convert -list format"
 502                 if ( preg_match( '/^([a-zA-Z0-9-]+):/', $path, $m ) ) {
 503                         if ( wfIsWindows() && is_dir( $m[0] ) ) {
 504                                 // OK, it's a drive letter
 505                                 // ImageMagick has a similar exception, see IsMagickConflict()
 506                         } else {
 507                                 throw new MWException( __METHOD__ . ': unexpected colon character in path name' );
 508                         }
 509                 }
 510
 511                 # If there are square brackets, add a do-nothing scene specification
 512                 # to force a literal interpretation
 513                 if ( $scene === false ) {
 514                         if ( strpos( $path, '[' ) !== false ) {
 515                                 $path .= '[0--1]';
 516                         }
 517                 } else {
 518                         $path .= "[$scene]";
 519                 }
 520                 return $path;
 521         }
 522
 523         /**
 524          * Retrieve the version of the installed ImageMagick
 525          * You can use PHPs version_compare() to use this value
 526          * Value is cached for one hour.
 527          * @return String representing the IM version.
 528          */
 529         protected function getMagickVersion() {
 530                 global $wgMemc;
 531
 532                 $cache = $wgMemc->get( "imagemagick-version" );
 533                 if ( !$cache ) {
 534                         global $wgImageMagickConvertCommand;
 535                         $cmd = wfEscapeShellArg( $wgImageMagickConvertCommand ) . ' -version';
 536                         wfDebug( __METHOD__ . ": Running convert -version\n" );
 537                         $retval = '';
 538                         $return = wfShellExec( $cmd, $retval );
 539                         $x = preg_match( '/Version: ImageMagick ([0-9]*\.[0-9]*\.[0-9]*)/', $return, $matches );
 540                         if ( $x != 1 ) {
 541                                 wfDebug( __METHOD__ . ": ImageMagick version check failed\n" );
 542                                 return null;
 543                         }
 544                         $wgMemc->set( "imagemagick-version", $matches[1], 3600 );
 545                         return $matches[1];
 546                 }
 547                 return $cache;
 548         }
 549
 550         static function imageJpegWrapper( $dst_image, $thumbPath ) {
 551                 imageinterlace( $dst_image );
 552                 imagejpeg( $dst_image, $thumbPath, 95 );
 553         }
 554
 555
 556         function getMetadata( $image, $filename ) {
 557                 global $wgShowEXIF;
 558                 if ( $wgShowEXIF && file_exists( $filename ) ) {
 559                         $exif = new Exif( $filename );
 560                         $data = $exif->getFilteredData();
 561                         if ( $data ) {
 562                                 $data['MEDIAWIKI_EXIF_VERSION'] = Exif::version();
 563                                 return serialize( $data );
 564                         } else {
 565                                 return '0';
 566                         }
 567                 } else {
 568                         return '';
 569                 }
 570         }
 571
 572         function getMetadataType( $image ) {
 573                 return 'exif';
 574         }
 575
 576         function isMetadataValid( $image, $metadata ) {
 577                 global $wgShowEXIF;
 578                 if ( !$wgShowEXIF ) {
 579                         # Metadata disabled and so an empty field is expected
 580                         return true;
 581                 }
 582                 if ( $metadata === '0' ) {
 583                         # Special value indicating that there is no EXIF data in the file
 584                         return true;
 585                 }
 586                 wfSuppressWarnings();
 587                 $exif = unserialize( $metadata );
 588                 wfRestoreWarnings();
 589                 if ( !isset( $exif['MEDIAWIKI_EXIF_VERSION'] ) ||
 590                         $exif['MEDIAWIKI_EXIF_VERSION'] != Exif::version() )
 591                 {
 592                         # Wrong version
 593                         wfDebug( __METHOD__ . ": wrong version\n" );
 594                         return false;
 595                 }
 596                 return true;
 597         }
 598
 599         /**
 600          * Get a list of EXIF metadata items which should be displayed when
 601          * the metadata table is collapsed.
 602          *
 603          * @return array of strings
 604          * @access private
 605          */
 606         function visibleMetadataFields() {
 607                 $fields = array();
 608                 $lines = explode( "\n", wfMsgForContent( 'metadata-fields' ) );
 609                 foreach ( $lines as $line ) {
 610                         $matches = array();
 611                         if ( preg_match( '/^\\*\s*(.*?)\s*$/', $line, $matches ) ) {
 612                                 $fields[] = $matches[1];
 613                         }
 614                 }
 615                 $fields = array_map( 'strtolower', $fields );
 616                 return $fields;
 617         }
 618
 619         function formatMetadata( $image ) {
 620                 $result = array(
 621                         'visible' => array(),
 622                         'collapsed' => array()
 623                 );
 624                 $metadata = $image->getMetadata();
 625                 if ( !$metadata ) {
 626                         return false;
 627                 }
 628                 $exif = unserialize( $metadata );
 629                 if ( !$exif ) {
 630                         return false;
 631                 }
 632                 unset( $exif['MEDIAWIKI_EXIF_VERSION'] );
 633                 $format = new FormatExif( $exif );
 634
 635                 $formatted = $format->getFormattedData();
 636                 // Sort fields into visible and collapsed
 637                 $visibleFields = $this->visibleMetadataFields();
 638                 foreach ( $formatted as $name => $value ) {
 639                         $tag = strtolower( $name );
 640                         self::addMeta( $result,
 641                                 in_array( $tag, $visibleFields ) ? 'visible' : 'collapsed',
 642                                 'exif',
 643                                 $tag,
 644                                 $value
 645                         );
 646                 }
 647                 return $result;
 648         }
 649
 650         /**
 651          * Try to read out the orientation of the file and return the angle that
 652          * the file needs to be rotated to be viewed
 653          *
 654          * @param $file File
 655          * @return int 0, 90, 180 or 270
 656          */
 657         public function getRotation( $file ) {
 658                 $data = $file->getMetadata();
 659                 if ( !$data ) {
 660                         return 0;
 661                 }
 662                 $data = unserialize( $data );
 663                 if ( isset( $data['Orientation'] ) ) {
 664                         # See http://sylvana.net/jpegcrop/exif_orientation.html
 665                         switch ( $data['Orientation'] ) {
 666                                 case 8:
 667                                         return 90;
 668                                 case 3:
 669                                         return 180;
 670                                 case 6:
 671                                         return 270;
 672                                 default:
 673                                         return 0;
 674                         }
 675                 }
 676                 return 0;
 677         }
 678         /**
 679          * Returns whether the current scaler supports rotation (im and gd do)
 680          *
 681          * @return bool
 682          */
 683         public function canRotate() {
 684                 $scaler = $this->getScalerType( null, false );
 685                 return $scaler == 'im' || $scaler == 'gd';
 686         }
 687
 688         /**
 689          * Rerurns whether the file needs to be rendered. Returns true if the
 690          * file requires rotation and we are able to rotate it.
 691          *
 692          * @param $file File
 693          * @return bool
 694          */
 695         public function mustRender( $file ) {
 696                 return $this->canRotate() && $this->getRotation( $file ) != 0;
 697         }
 698 }