includes/Exif.php

   1 <?php
   2 if (defined('MEDIAWIKI')) {
   3 /**
   4  * @package MediaWiki
   5  * @subpackage Metadata
   6  *
   7  * @author Ævar Arnfjörð Bjarmason <avarab@gmail.com>
   8  * @copyright Copyright © 2005, Ævar Arnfjörð Bjarmason
   9  * @license http://www.gnu.org/copyleft/gpl.html GNU General Public License
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License along
  22  * with this program; if not, write to the Free Software Foundation, Inc.,
  23  * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  24  * http://www.gnu.org/copyleft/gpl.html
  25  *
  26  * @link http://exif.org/Exif2-2.PDF The Exif 2.2 specification
  27  * @bug 1555, 1947
  28  */
  29
  30 /**#@+
  31  * Exif tag type definition
  32  */
  33 define('MW_EXIF_BYTE', 1);              # An 8-bit unsigned integer.
  34 define('MW_EXIF_ASCII', 2);             # An 8-bit byte containing one 7-bit ASCII code. The final byte is terminated with NULL.
  35 define('MW_EXIF_SHORT', 3);             # A 16-bit (2-byte) unsigned integer.
  36 define('MW_EXIF_LONG', 4);              # A 32-bit (4-byte) unsigned integer.
  37 define('MW_EXIF_RATIONAL', 5);          # Two LONGs. The first LONG is the numerator and the second LONG expresses the denominator
  38 define('MW_EXIF_UNDEFINED', 7);         # An 8-bit byte that can take any value depending on the field definition
  39 define('MW_EXIF_SLONG', 9);             # A 32-bit (4-byte) signed integer (2's complement notation),
  40 define('MW_EXIF_SRATIONAL', 10);        # Two SLONGs. The first SLONG is the numerator and the second SLONG is the denominator.
  41 /**#@-*/
  42
  43
  44 /**
  45  * @package MediaWiki
  46  * @subpackage Metadata
  47  */
  48 class Exif {
  49         /**#@+
  50          * @var array
  51          */
  52
  53         /**
  54          * Exif tags grouped by category, the tagname itself is the key and the type
  55          * is the value, in the case of more than one possible value type they are
  56          * seperated by commas.
  57          *
  58          * @access private
  59          */
  60         var $mExif;
  61
  62         /**
  63          * A one dimentional array of all Exif tags
  64          */
  65         var $mFlatExif;
  66
  67         /**#@-*/
  68
  69         /**
  70          * Constructor
  71          */
  72         function Exif() {
  73                 /**
  74                  * Page numbers here refer to pages in the EXIF 2.2 standard
  75                  *
  76                  * @link http://exif.org/Exif2-2.PDF The Exif 2.2 specification
  77                  */
  78                 $this->mExif = array(
  79                         # TIFF Rev. 6.0 Attribute Information (p22)
  80                         'tiff' => array(
  81                                 # Tags relating to image structure
  82                                 'structure' => array(
  83                                         'ImageWidth' => MW_EXIF_SHORT.','.MW_EXIF_LONG,         # Image width
  84                                         'ImageLength' => MW_EXIF_SHORT.','.MW_EXIF_LONG,        # Image height
  85                                         'BitsPerSample' => MW_EXIF_SHORT,                       # Number of bits per component
  86                                         # "When a primary image is JPEG compressed, this designation is not"
  87                                         # "necessary and is omitted." (p23)
  88                                         'Compression' => MW_EXIF_SHORT,                         # Compression scheme #p23
  89                                         'PhotometricInterpretation' => MW_EXIF_SHORT,           # Pixel composition #p23
  90                                         'Orientation' => MW_EXIF_SHORT,                         # Orientation of image #p24
  91                                         'SamplesPerPixel' => MW_EXIF_SHORT,                     # Number of components
  92                                         'PlanarConfiguration' => MW_EXIF_SHORT,                 # Image data arrangement #p24
  93                                         'YCbCrSubSampling' => MW_EXIF_SHORT,                    # Subsampling ratio of Y to C #p24
  94                                         'YCbCrPositioning' => MW_EXIF_SHORT,                    # Y and C positioning #p24-25
  95                                         'XResolution' => MW_EXIF_RATIONAL,                      # Image resolution in width direction
  96                                         'YResolution' => MW_EXIF_RATIONAL,                      # Image resolution in height direction
  97                                         'ResolutionUnit' => MW_EXIF_SHORT,                      # Unit of X and Y resolution #(p26)
  98                                 ),
  99
 100                                 # Tags relating to recording offset
 101                                 'offset' => array(
 102                                         'StripOffsets' => MW_EXIF_SHORT.','.MW_EXIF_LONG,                       # Image data location
 103                                         'RowsPerStrip' => MW_EXIF_SHORT.','.MW_EXIF_LONG,                       # Number of rows per strip
 104                                         'StripByteCounts' => MW_EXIF_SHORT.','.MW_EXIF_LONG,                    # Bytes per compressed strip
 105                                         'JPEGInterchangeFormat' => MW_EXIF_SHORT.','.MW_EXIF_LONG,              # Offset to JPEG SOI
 106                                         'JPEGInterchangeFormatLength' => MW_EXIF_SHORT.','.MW_EXIF_LONG,        # Bytes of JPEG data
 107                                 ),
 108
 109                                 # Tags relating to image data characteristics
 110                                 'characteristics' => array(
 111                                         'TransferFunction' => MW_EXIF_SHORT,            # Transfer function
 112                                         'WhitePoint' => MW_EXIF_RATIONAL,               # White point chromaticity
 113                                         'PrimaryChromaticities' => MW_EXIF_RATIONAL,    # Chromaticities of primarities
 114                                         'YCbCrCoefficients' => MW_EXIF_RATIONAL,        # Color space transformation matrix coefficients #p27
 115                                         'ReferenceBlackWhite' => MW_EXIF_RATIONAL       # Pair of black and white reference values
 116                                 ),
 117
 118                                 # Other tags
 119                                 'other' => array(
 120                                         'DateTime' => MW_EXIF_ASCII,            # File change date and time
 121                                         'ImageDescription' => MW_EXIF_ASCII,    # Image title
 122                                         'Make' => MW_EXIF_ASCII,                # Image input equipment manufacturer
 123                                         'Model' => MW_EXIF_ASCII,               # Image input equipment model
 124                                         'Software' => MW_EXIF_ASCII,            # Software used
 125                                         'Artist' => MW_EXIF_ASCII,              # Person who created the image
 126                                         'Copyright' => MW_EXIF_ASCII,           # Copyright holder
 127                                 ),
 128                         ),
 129
 130                         # Exif IFD Attribute Information (p30-31)
 131                         'exif' => array(
 132                                 # Tags relating to version
 133                                 'version' => array(
 134                                         # TODO: NOTE: Nonexistence of this field is taken to mean nonconformance
 135                                         # to the EXIF 2.1 AND 2.2 standards
 136                                         'ExifVersion' => MW_EXIF_UNDEFINED,     # Exif version
 137                                         'FlashpixVersion' => MW_EXIF_UNDEFINED, # Supported Flashpix version #p32
 138                                 ),
 139
 140                                 # Tags relating to Image Data Characteristics
 141                                 'characteristics' => array(
 142                                         'ColorSpace' => MW_EXIF_SHORT,          # Color space information #p32
 143                                 ),
 144
 145                                 # Tags relating to image configuration
 146                                 'configuration' => array(
 147                                         'ComponentsConfiguration' => MW_EXIF_UNDEFINED,         # Meaning of each component #p33
 148                                         'CompressedBitsPerPixel' => MW_EXIF_RATIONAL,           # Image compression mode
 149                                         'PixelYDimension' => MW_EXIF_SHORT.','.MW_EXIF_LONG,    # Valid image width
 150                                         'PixelXDimension' => MW_EXIF_SHORT.','.MW_EXIF_LONG,    # Valind image height
 151                                 ),
 152
 153                                 # Tags relating to related user information
 154                                 'user' => array(
 155                                         'MakerNote' => MW_EXIF_UNDEFINED,                       # Manufacturer notes
 156                                         'UserComment' => MW_EXIF_UNDEFINED,                     # User comments #p34
 157                                 ),
 158
 159                                 # Tags relating to related file information
 160                                 'related' => array(
 161                                         'RelatedSoundFile' => MW_EXIF_ASCII,                    # Related audio file
 162                                 ),
 163
 164                                 # Tags relating to date and time
 165                                 'dateandtime' => array(
 166                                         'DateTimeOriginal' => MW_EXIF_ASCII,                    # Date and time of original data generation #p36
 167                                         'DateTimeDigitized' => MW_EXIF_ASCII,                   # Date and time of original data generation
 168                                         'SubSecTime' => MW_EXIF_ASCII,                          # DateTime subseconds
 169                                         'SubSecTimeOriginal' => MW_EXIF_ASCII,                  # DateTimeOriginal subseconds
 170                                         'SubSecTimeDigitized' => MW_EXIF_ASCII,                 # DateTimeDigitized subseconds
 171                                 ),
 172
 173                                 # Tags relating to picture-taking conditions (p31)
 174                                 'conditions' => array(
 175                                         'ExposureTime' => MW_EXIF_RATIONAL,                     # Exposure time
 176                                         'FNumber' => MW_EXIF_RATIONAL,                          # F Number
 177                                         'ExposureProgram' => MW_EXIF_SHORT,                     # Exposure Program #p38
 178                                         'SpectralSensitivity' => MW_EXIF_ASCII,                 # Spectral sensitivity
 179                                         'ISOSpeedRatings' => MW_EXIF_SHORT,                     # ISO speed rating
 180                                         'OECF' => MW_EXIF_UNDEFINED,                            # Optoelectronic conversion factor
 181                                         'ShutterSpeedValue' => MW_EXIF_SRATIONAL,               # Shutter speed
 182                                         'ApertureValue' => MW_EXIF_RATIONAL,                    # Aperture
 183                                         'BrightnessValue' => MW_EXIF_SRATIONAL,                 # Brightness
 184                                         'ExposureBiasValue' => MW_EXIF_SRATIONAL,               # Exposure bias
 185                                         'MaxApertureValue' => MW_EXIF_RATIONAL,                 # Maximum land aperture
 186                                         'SubjectDistance' => MW_EXIF_RATIONAL,                  # Subject distance
 187                                         'MeteringMode' => MW_EXIF_SHORT,                        # Metering mode #p40
 188                                         'LightSource' => MW_EXIF_SHORT,                         # Light source #p40-41
 189                                         'Flash' => MW_EXIF_SHORT,                               # Flash #p41-42
 190                                         'FocalLength' => MW_EXIF_RATIONAL,                      # Lens focal length
 191                                         'SubjectArea' => MW_EXIF_SHORT,                         # Subject area
 192                                         'FlashEnergy' => MW_EXIF_RATIONAL,                      # Flash energy
 193                                         'SpatialFrequencyResponse' => MW_EXIF_UNDEFINED,        # Spatial frequency response
 194                                         'FocalPlaneXResolution' => MW_EXIF_RATIONAL,            # Focal plane X resolution
 195                                         'FocalPlaneYResolution' => MW_EXIF_RATIONAL,            # Focal plane Y resolution
 196                                         'FocalPlaneResolutionUnit' => MW_EXIF_SHORT,            # Focal plane resolution unit
 197                                         'SubjectLocation' => MW_EXIF_SHORT,                     # Subject location
 198                                         'ExposureIndex' => MW_EXIF_RATIONAL,                    # Exposure index
 199                                         'SensingMethod' => MW_EXIF_SHORT,                       # Sensing method #p46
 200                                         'FileSource' => MW_EXIF_UNDEFINED,                      # File source #p47
 201                                         'SceneType' => MW_EXIF_UNDEFINED,                       # Scene type #p47
 202                                         'CFAPattern' => MW_EXIF_UNDEFINED,                      # CFA pattern
 203                                         'CustomRendered' => MW_EXIF_SHORT,                      # Custom image processing #p48
 204                                         'ExposureMode' => MW_EXIF_SHORT,                        # Exposure mode #p48
 205                                         'WhiteBalance' => MW_EXIF_SHORT,                        # White Balance #p49
 206                                         'DigitalZoomRatio' => MW_EXIF_RATIONAL,                 # Digital zoom ration
 207                                         'FocalLengthIn35mmFilm' => MW_EXIF_SHORT,               # Focal length in 35 mm film
 208                                         'SceneCaptureType' => MW_EXIF_SHORT,                    # Scene capture type #p49
 209                                         'GainControl' => MW_EXIF_RATIONAL,                      # Scene control #p49-50
 210                                         'Contrast' => MW_EXIF_SHORT,                            # Contrast #p50
 211                                         'Saturation' => MW_EXIF_SHORT,                          # Saturation #p50
 212                                         'Sharpness' => MW_EXIF_SHORT,                           # Sharpness #p50
 213                                         'DeviceSettingDescription' => MW_EXIF_UNDEFINED,        # Desice settings description
 214                                         'SubjectDistanceRange' => MW_EXIF_SHORT,                # Subject distance range #p51
 215                                 ),
 216
 217                                 'other' => array(
 218                                         'ImageUniqueID' => MW_EXIF_ASCII,       # Unique image ID
 219                                 ),
 220                         ),
 221
 222                         # GPS Attribute Information (p52)
 223                         'gps' => array(
 224                                 'GPSVersionID' => MW_EXIF_BYTE,                 # GPS tag version
 225                                 'GPSLatitudeRef' => MW_EXIF_ASCII,              # North or South Latitude #p52-53
 226                                 'GPSLatitude' => MW_EXIF_RATIONAL,              # Latitude
 227                                 'GPSLongitudeRef' => MW_EXIF_ASCII,             # East or West Longitude #p53
 228                                 'GPSLongitude' => MW_EXIF_RATIONAL,             # Longitude
 229                                 'GPSAltitudeRef' => MW_EXIF_BYTE,               # Altitude reference
 230                                 'GPSAltitude' => MW_EXIF_RATIONAL,              # Altitude
 231                                 'GPSTimeStamp' => MW_EXIF_RATIONAL,             # GPS time (atomic clock)
 232                                 'GPSSatellites' => MW_EXIF_ASCII,               # Satellites used for measurement
 233                                 'GPSStatus' => MW_EXIF_ASCII,                   # Receiver status #p54
 234                                 'GPSMeasureMode' => MW_EXIF_ASCII,              # Measurement mode #p54-55
 235                                 'GPSDOP' => MW_EXIF_RATIONAL,                   # Measurement precision
 236                                 'GPSSpeedRef' => MW_EXIF_ASCII,                 # Speed unit #p55
 237                                 'GPSSpeed' => MW_EXIF_RATIONAL,                 # Speed of GPS receiver
 238                                 'GPSTrackRef' => MW_EXIF_ASCII,                 # Reference for direction of movement #p55
 239                                 'GPSTrack' => MW_EXIF_RATIONAL,                 # Direction of movement
 240                                 'GPSImgDirectionRef' => MW_EXIF_ASCII,          # Reference for direction of image #p56
 241                                 'GPSImgDirection' => MW_EXIF_RATIONAL,          # Direction of image
 242                                 'GPSMapDatum' => MW_EXIF_ASCII,                 # Geodetic survey data used
 243                                 'GPSDestLatitudeRef' => MW_EXIF_ASCII,          # Reference for latitude of destination #p56
 244                                 'GPSDestLatitude' => MW_EXIF_RATIONAL,          # Latitude destination
 245                                 'GPSDestLongitudeRef' => MW_EXIF_ASCII,         # Reference for longitude of destination #p57
 246                                 'GPSDestLongitude' => MW_EXIF_RATIONAL,         # Longitude of destination
 247                                 'GPSDestBearingRef' => MW_EXIF_ASCII,           # Reference for bearing of destination #p57
 248                                 'GPSDestBearing' => MW_EXIF_RATIONAL,           # Bearing of destination
 249                                 'GPSDestDistanceRef' => MW_EXIF_ASCII,          # Reference for distance to destination #p57-58
 250                                 'GPSDestDistance' => MW_EXIF_RATIONAL,          # Distance to destination
 251                                 'GPSProcessingMethod' => MW_EXIF_UNDEFINED,     # Name of GPS processing method
 252                                 'GPSAreaInformation' => MW_EXIF_UNDEFINED,      # Name of GPS area
 253                                 'GPSDateStamp' => MW_EXIF_ASCII,                # GPS date
 254                                 'GPSDifferential' => MW_EXIF_SHORT,             # GPS differential correction
 255                         ),
 256                 );
 257
 258                 $this->makeFlatExifTags();
 259         }
 260
 261         /**
 262          * Generate a flat list of the exif tags
 263          */
 264         function makeFlatExifTags() {
 265                 $this->extractTags( $this->mExif );
 266         }
 267
 268         /**
 269          * A recursing extractor function used by makeFlatExifTags()
 270          *
 271          * Note: This used to use an array_walk function, but it made PHP5
 272          * segfault, see `cvs diff -u -r 1.4 -r 1.5 Exif.php`
 273          */
 274         function extractTags( $tagset ) {
 275                 foreach( $tagset as $key => $val ) {
 276                         if( is_array( $val ) ) {
 277                                 $this->extractTags( $val );
 278                         } else {
 279                                 $this->mFlatExif[$key] = $val;
 280                         }
 281                 }
 282         }
 283
 284          /**
 285           * The version of the output format
 286           *
 287           * Before the actual metadata information is saved in the database we
 288           * strip some of it since we don't want to save things like thumbnails
 289           * which usually accompany Exif data. This value gets saved in the
 290           * database along with the actual Exif data, and if the version in the
 291           * database doesn't equal the value returned by this function the Exif
 292           * data is regenerated.
 293           *
 294           * @return int
 295           */
 296         function version() {
 297                 return 1; // We don't need no bloddy constants!
 298         }
 299
 300         /**#@+
 301          * Validates if a tag value is of the type it should be according to the Exif spec
 302          *
 303          * @param mixed $in The input value to check
 304          * @return bool
 305          */
 306         function isByte( $in ) {
 307                 $fname = 'isByte';
 308                 if ( sprintf('%d', $in) === $in && $in >= 0 && $in <= 255 ) {
 309                         wfDebug("Exif::$fname: accepted: '$in' (type: " . gettype( $in ) . ")\n");
 310                         return true;
 311                 } else {
 312                         wfDebug("Exif::$fname: rejected: '$in' (type: " . gettype( $in ) . ")\n");
 313                         return false;
 314                 }
 315         }
 316
 317         function isASCII( $in ) {
 318                 wfDebug("Exif::isASCII: input was '$in'\n");
 319                 if ( preg_match( "/^\s*$/", $in ) ) {
 320                         return false;
 321                 }
 322                 return true;
 323         }
 324
 325         function isShort( $in ) {
 326                 $fname = 'isShort';
 327                 if ( sprintf('%d', $in) === $in && $in >= 0 && $in <= 65536 ) {
 328                         wfDebug("Exif::$fname: accepted: '$in' (type: " . gettype( $in ) . ")\n");
 329                         return true;
 330                 } else {
 331                         wfDebug("Exif::$fname: rejected: '$in' (type: " . gettype( $in ) . ")\n");
 332                         return false;
 333                 }
 334         }
 335
 336         function isLong( $in ) {
 337                 $fname = 'isLong';
 338                 if ( sprintf('%d', $in) === $in && $in >= 0 && $in <= 4294967296 ) {
 339                         wfDebug("Exif::$fname: accepted: '$in' (type: " . gettype( $in ) . ")\n");
 340                         return true;
 341                 } else {
 342                         wfDebug("Exif::$fname: rejected: '$in' (type: " . gettype( $in ) . ")\n");
 343                         return false;
 344                 }
 345         }
 346
 347         function isRational( $in ) {
 348                 $fname = 'isRational';
 349                 if ( strpos( $in, '/' ) === false ) {
 350                         wfDebug("Exif::$fname: fed a non-fraction value: (type: " . gettype( $in ) . "; data: '$in')\n");
 351                         return false;
 352                 } else {
 353                         $a = explode( '/', $in, 2 );
 354                         if ( $this->isLong( $a[0] ) && $this->isLong( $a[1] ) ) {
 355                                 wfDebug("Exif::$fname: accepted: '$in' (type: " . gettype( $in ) . ")\n");
 356                                 return true;
 357                         } else {
 358                                 wfDebug("Exif::$fname: rejected: '$in' (type: " . gettype( $in ) . ")\n");
 359                                 return false;
 360                         }
 361                 }
 362         }
 363
 364         /**
 365          * In order not to output binary gibberish such as raw thumbnails we
 366          * return false here
 367          *
 368          * @todo We might actually want to display some of the UNDEFINED
 369          *       stuff, but we strip it for now.
 370          */
 371         function isUndefined( $in ) {
 372                 $fname = 'isUndefined';
 373                 wfDebug("Exif::$fname: input was '$in'\n");
 374                 if ( preg_match( "/^\d{4}$/", $in ) ) { // Allow ExifVersion and FlashpixVersion
 375                         return true;
 376                 } else {
 377                         return false;
 378                 }
 379         }
 380
 381         function isSlong( $in ) {
 382                 $fname = 'isSlong';
 383                 if ( $this->isLong( abs( $in ) ) ) {
 384                         wfDebug("Exif::$fname: accepted: '$in' (type: " . gettype( $in ) . ")\n");
 385                         return true;
 386                 } else {
 387                         wfDebug("Exif::$fname: rejected: '$in' (type: " . gettype( $in ) . ")\n");
 388                         return false;
 389                 }
 390         }
 391
 392         function isSrational( $in ) {
 393                 $fname = 'isSrational';
 394                 if ( strpos( $in, '/' ) === false ) {
 395                          wfDebug("Exif::$fname: fed a non-fraction value: (type: " . gettype( $in ) . "; data: '$in')\n");
 396                          return false;
 397                 } else {
 398                         $a = explode( '/', $in, 2 );
 399                         if ( $this->isSlong( $a[0] ) && $this->isSlong( $a[1] ) ) {
 400                                  wfDebug("Exif::$fname: accepted: '$in' (type: " . gettype( $in ) . ")\n");
 401                                  return true;
 402                         } else {
 403                                 wfDebug("Exif::$fname: rejected: '$in' (type: " . gettype( $in ) . ")\n");
 404                                 return false;
 405                         }
 406                 }
 407         }
 408         /**#@-*/
 409
 410         /**
 411          * Validates if a tag has a legal value according to the Exif spec
 412          *
 413          * @param string $tag The tag to check
 414          * @param mixed  $val The value of the tag
 415          * @return bool
 416          */
 417         function validate( $tag, $val ) {
 418                 // Fucks up if not typecast
 419                 switch( (string)$this->mFlatExif[$tag] ) {
 420                         case (string)MW_EXIF_BYTE:
 421                                 return $this->isByte( $val );
 422                         case (string)MW_EXIF_ASCII:
 423                                 return $this->isASCII( $val );
 424                         case (string)MW_EXIF_SHORT:
 425                                 return $this->isShort( $val );
 426                         case (string)MW_EXIF_LONG:
 427                                 return $this->isLong( $val );
 428                         case (string)MW_EXIF_RATIONAL:
 429                                 return $this->isRational( $val );
 430                         case (string)MW_EXIF_UNDEFINED:
 431                                 return $this->isUndefined( $val );
 432                         case (string)MW_EXIF_SLONG:
 433                                 return $this->isSlong( $val );
 434                         case (string)MW_EXIF_SRATIONAL:
 435                                 return $this->isSrational( $val );
 436                         case (string)MW_EXIF_SHORT.','.MW_EXIF_LONG:
 437                                 return $this->isShort( $val ) || $this->isLong( $val );
 438                         default:
 439                                 wfDebug( "Exif::validate: The tag \"$tag\" in unrecognized (type: " . gettype( $val ) . "; contents: $val)\n" );
 440                                 return false;
 441                 }
 442         }
 443
 444         /**
 445          * Numbers given by Exif user agents are often magical, that is they
 446          * should be replaced by a detailed explanation depending on their
 447          * value which most of the time are plain integers. This function
 448          * formats Exif values into human readable form.
 449          *
 450          * @param string $tag The tag to be formatted
 451          * @param mixed  $val The value of the tag
 452          * @return string
 453          */
 454         function format( $tag, $val ) {
 455                 global $wgLang;
 456
 457                 switch( $tag ) {
 458                 case 'Compression':
 459                         switch( $val ) {
 460                         case 1: case 6:
 461                                 return $this->msg( $tag, $val );
 462                         default:
 463                                 return $val;
 464                         }
 465
 466                 case 'PhotometricInterpretation':
 467                         switch( $val ) {
 468                         case 2: case 6:
 469                                 return $this->msg( $tag, $val );
 470                         default:
 471                                 return $val;
 472                         }
 473
 474                 case 'Orientation':
 475                         switch( $val ) {
 476                         case 1: case 2: case 3: case 4: case 5: case 6: case 7: case 8:
 477                                 return $this->msg( $tag, $val );
 478                         default:
 479                                 return $val;
 480                         }
 481
 482                 case 'PlanarConfiguration':
 483                         switch( $val ) {
 484                         case 1: case 2:
 485                                 return $this->msg( $tag, $val );
 486                         default:
 487                                 return $val;
 488                         }
 489
 490                 // TODO: YCbCrSubSampling
 491                 // TODO: YCbCrPositioning
 492                 // TODO: If this field does not exists use 2
 493                 case 'ResolutionUnit': #p26
 494                         switch( $val ) {
 495                         case 2: case 3:
 496                                 return $this->msg( $tag, $val );
 497                         default:
 498                                 return $val;
 499                         }
 500
 501                 // TODO: YCbCrCoefficients  #p27 (see annex E)
 502                 case 'ExifVersion': case 'FlashpixVersion':
 503                         return "$val"/100;
 504
 505                 case 'ColorSpace':
 506                         switch( $val ) {
 507                         case 1: case 'FFFF.H':
 508                                 return $this->msg( $tag, $val );
 509                         default:
 510                                 return $val;
 511                         }
 512
 513                 case 'ComponentsConfiguration':
 514                         switch( $val ) {
 515                         case 0: case 1: case 2: case 3: case 4: case 5: case 6:
 516                                 return $this->msg( $tag, $val );
 517                         default:
 518                                 return $val;
 519                         }
 520
 521                 case 'DateTime':
 522                 case 'DateTimeOriginal':
 523                 case 'DateTimeDigitized':
 524                         return $wgLang->timeanddate( wfTimestamp(TS_MW, $val) );
 525
 526                 case 'ExposureProgram':
 527                         switch( $val ) {
 528                         case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: case 8:
 529                                 return $this->msg( $tag, $val );
 530                         default:
 531                                 return $val;
 532                         }
 533
 534                 case 'MeteringMode':
 535                         switch( $val ) {
 536                         case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7: case 255:
 537                                 return $this->msg( $tag, $val );
 538                         default:
 539                                 return $val;
 540                         }
 541
 542                 case 'LightSource':
 543                         switch( $val ) {
 544                         case 0: case 1: case 2: case 3: case 4: case 9: case 10: case 11:
 545                         case 12: case 13: case 14: case 15: case 17: case 18: case 19: case 20:
 546                         case 21: case 22: case 23: case 24: case 255:
 547                                 return $this->msg( $tag, $val );
 548                         default:
 549                                 return $val;
 550                         }
 551
 552                 // TODO: Flash
 553                 case 'SensingMethod':
 554                         switch( $val ) {
 555                         case 1: case 2: case 3: case 4: case 5: case 7: case 8:
 556                                 return $this->msg( $tag, $val );
 557                         default:
 558                                 return $val;
 559                         }
 560
 561                 case 'FileSource':
 562                         switch( $val ) {
 563                         case 3:
 564                                 return $this->msg( $tag, $val );
 565                         default:
 566                                 return $val;
 567                         }
 568
 569                 case 'SceneType':
 570                         switch( $val ) {
 571                         case 1:
 572                                 return $this->msg( $tag, $val );
 573                         default:
 574                                 return $val;
 575                         }
 576
 577                 case 'CustomRendered':
 578                         switch( $val ) {
 579                         case 0: case 1:
 580                                 return $this->msg( $tag, $val );
 581                         default:
 582                                 return $val;
 583                         }
 584
 585                 case 'ExposureMode':
 586                         switch( $val ) {
 587                         case 0: case 1: case 2:
 588                                 return $this->msg( $tag, $val );
 589                         default:
 590                                 return $val;
 591                         }
 592
 593                 case 'WhiteBalance':
 594                         switch( $val ) {
 595                         case 0: case 1:
 596                                 return $this->msg( $tag, $val );
 597                         default:
 598                                 return $val;
 599                         }
 600
 601                 case 'SceneCaptureType':
 602                         switch( $val ) {
 603                         case 0: case 1: case 2: case 3:
 604                                 return $this->msg( $tag, $val );
 605                         default:
 606                                 return $val;
 607                         }
 608
 609                 case 'GainControl':
 610                         switch( $val ) {
 611                         case 0: case 1: case 2: case 3: case 4:
 612                                 return $this->msg( $tag, $val );
 613                         default:
 614                                 return $val;
 615                         }
 616
 617                 case 'Contrast':
 618                         switch( $val ) {
 619                         case 0: case 1: case 2:
 620                                 return $this->msg( $tag, $val );
 621                         default:
 622                                 return $val;
 623                         }
 624
 625                 case 'Saturation':
 626                         switch( $val ) {
 627                         case 0: case 1: case 2:
 628                                 return $this->msg( $tag, $val );
 629                         default:
 630                                 return $val;
 631                         }
 632
 633                 case 'Sharpness':
 634                         switch( $val ) {
 635                         case 0: case 1: case 2:
 636                                 return $this->msg( $tag, $val );
 637                         default:
 638                                 return $val;
 639                         }
 640
 641                 case 'SubjectDistanceRange':
 642                         switch( $val ) {
 643                         case 0: case 1: case 2: case 3:
 644                                 return $this->msg( $tag, $val );
 645                         default:
 646                                 return $val;
 647                         }
 648
 649                 case 'GPSLatitudeRef':
 650                         switch( $val ) {
 651                         case 'N': case 'S':
 652                                 return $this->msg( $tag, $val );
 653                         default:
 654                                 return $val;
 655                         }
 656
 657                 case 'GPSLongitudeRef':
 658                         switch( $val ) {
 659                         case 'E': case 'W':
 660                                 return $this->msg( $tag, $val );
 661                         default:
 662                                 return $val;
 663                         }
 664
 665                 case 'GPSStatus':
 666                         switch( $val ) {
 667                         case 'A': case 'V':
 668                                 return $this->msg( $tag, $val );
 669                         default:
 670                                 return $val;
 671                         }
 672
 673                 case 'GPSMeasureMode':
 674                         switch( $val ) {
 675                         case 2: case 3:
 676                                 return $this->msg( $tag, $val );
 677                         default:
 678                                 return $val;
 679                         }
 680
 681                 case 'GPSSpeedRef':
 682                         switch( $val ) {
 683                         case 'K': case 'M': case 'N':
 684                                 return $this->msg( $tag, $val );
 685                         default:
 686                                 return $val;
 687                         }
 688
 689                 case 'GPSTrackRef':
 690                         switch( $val ) {
 691                         case 'T': case 'M':
 692                                 return $this->msg( $tag, $val );
 693                         default:
 694                                 return $val;
 695                         }
 696
 697                 case 'GPSImgDirectionRef':
 698                         switch( $val ) {
 699                         case 'T': case 'M':
 700                                 return $this->msg( $tag, $val );
 701                         default:
 702                                 return $val;
 703                         }
 704
 705                 case 'GPSDestLatitudeRef':
 706                         switch( $val ) {
 707                         case 'N': case 'S':
 708                                 return $this->msg( $tag, $val );
 709                         default:
 710                                 return $val;
 711                         }
 712
 713                 case 'GPSDestLongitudeRef':
 714                         switch( $val ) {
 715                         case 'E': case 'W':
 716                                 return $this->msg( $tag, $val );
 717                         default:
 718                                 return $val;
 719                         }
 720
 721                 case 'GPSDestBearingRef':
 722                         switch( $val ) {
 723                         case 'T': case 'M':
 724                                 return $this->msg( $tag, $val );
 725                         default:
 726                                 return $val;
 727                         }
 728
 729                 case 'GPSDateStamp':
 730                         return $wgLang->date( substr( $val, 0, 4 ) . substr( $val, 5, 2 ) . substr( $val, 8, 2 ) . '000000' );
 731
 732                 // This is not in the Exif standard, just a special
 733                 // case for our purposes which enables wikis to wikify
 734                 // the make, model and software name to link to their articles.
 735                 case 'Make':
 736                 case 'Model':
 737                 case 'Software':
 738                         return wfMsg( strtolower( "exif-$tag-value" ), $val );
 739                 default:
 740                         if ( preg_match( '/^(\d+)\/(\d+)$/', $val, $m ) ) {
 741                                 return $m[2] != 0 ? $m[1]/$m[2] : $val;
 742                         }
 743                         return $val;
 744                 }
 745         }
 746
 747         /**
 748          * Conviniance function for format()
 749          *
 750          * @param string $tag The tag name to pass on
 751          * @param string $val The value of the tag
 752          * @return string A wfMsg of "exif-$tag-$val" in lower case
 753          */
 754         function msg( $tag, $val ) {
 755                 return wfMsg( strtolower("exif-$tag-$val") );
 756         }
 757 }
 758
 759 } // MEDIAWIKI