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  * @link http://exif.org/Exif2-2.PDF The Exif 2.2 specification
  12  * @bug 1555, 1947
  13  */
  14
  15 /**
  16  * @package MediaWiki
  17  * @subpackage Metadata
  18  */
  19 class Exif {
  20         /**#@+
  21          * @var array
  22          */
  23
  24         /**
  25          * Exif tags grouped by category, the tagname itself is the key and the type
  26          * is the value, in the case of more than one possible value type they are
  27          * seperated by commas.
  28          *
  29          * @access private
  30          */
  31         var $mExif;
  32
  33         /**
  34          * A one dimentional array of all Exif tags
  35          */
  36         var $mFlatExif;
  37
  38         /**
  39          * A one dimentional array of all Exif tags that we'd want to save in
  40          * the database or present on a page.
  41          */
  42         var $mValidExif;
  43
  44         /**#@-*/
  45
  46         /**
  47          * Constructor
  48          */
  49         function Exif() {
  50                 /**#@+
  51                  * Exif tag type definition
  52                  */
  53                 define('BYTE', 1);              # An 8-bit unsigned integer.
  54                 define('ASCII', 2);             # An 8-bit byte containing one 7-bit ASCII code. The final byte is terminated with NULL.
  55                 define('SHORT', 3);             # A 16-bit (2-byte) unsigned integer.
  56                 define('LONG', 4);              # A 32-bit (4-byte) unsigned integer.
  57                 define('RATIONAL', 5);          # Two LONGs. The first LONG is the numerator and the second LONG expresses the denominator
  58                 define('UNDEFINED', 7);         # An 8-bit byte that can take any value depending on the field definition
  59                 define('SLONG', 9);             # A 32-bit (4-byte) signed integer (2's complement notation),
  60                 define('SRATIONAL', 10);        # Two SLONGs. The first SLONG is the numerator and the second SLONG is the denominator.
  61                 /**#@-*/
  62
  63                 /**
  64                  * Page numbers here refer to pages in the EXIF 2.2 standard
  65                  *
  66                  * @link http://exif.org/Exif2-2.PDF The Exif 2.2 specification
  67                  */
  68                 $this->mExif = array(
  69                         # TIFF Rev. 6.0 Attribute Information (p22)
  70                         'tiff' => array(
  71                                 # Tags relating to image structure
  72                                 'structure' => array(
  73                                         'ImageWidth' => SHORT.','.LONG,         # Image width
  74                                         'ImageLength' => SHORT.','.LONG,        # Image height
  75                                         'BitsPerSample' => SHORT,               # Number of bits per component
  76                                         # "When a primary image is JPEG compressed, this designation is not"
  77                                         # "necessary and is omitted." (p23)
  78                                         'Compression' => SHORT,                 # Compression scheme
  79                                         'PhotometricInterpretation' => SHORT,   # Pixel composition #p23
  80                                         'Orientation' => SHORT,                 # Orientation of image #p24
  81                                         'SamplesPerPixel' => SHORT,             # Number of components
  82                                         'PlanarConfiguration' => SHORT,         # Image data arrangement #p24
  83                                         'YCbCrSubSampling' => SHORT,            # Subsampling ratio of Y to C #p24
  84                                         'YCbCrPositioning' => SHORT,            # Y and C positioning #p24-25
  85                                         'XResolution' => RATIONAL,              # Image resolution in width direction
  86                                         'YResolution' => RATIONAL,              # Image resolution in height direction
  87                                         'ResolutionUnit' => SHORT,              # Unit of X and Y resolution #(p26)
  88                                 ),
  89
  90                                 # Tags relating to recording offset
  91                                 'offset' => array(
  92                                         'StripOffsets' => SHORT.','.LONG,                       # Image data location
  93                                         'RowsPerStrip' => SHORT.','.LONG,                       # Number of rows per strip
  94                                         'StripByteCounts' => SHORT.','.LONG,                    # Bytes per compressed strip
  95                                         'JPEGInterchangeFormat' => SHORT.','.LONG,              # Offset to JPEG SOI
  96                                         'JPEGInterchangeFormatLength' => SHORT.','.LONG,        # Bytes of JPEG data
  97                                 ),
  98
  99                                 # Tags relating to image data characteristics
 100                                 'characteristics' => array(
 101                                         'TransferFunction' => SHORT,            # Transfer function
 102                                         'WhitePoint' => RATIONAL,               # White point chromaticity
 103                                         'PrimaryChromaticities' => RATIONAL,    # Chromaticities of primarities
 104                                         'YCbCrCoefficients' => RATIONAL,        # Color space transformation matrix coefficients #p27
 105                                         'ReferenceBlackWhite' => RATIONAL       # Pair of black and white reference values
 106                                 ),
 107
 108                                 # Other tags
 109                                 'other' => array(
 110                                         'DateTime' => ASCII,            # File change date and time
 111                                         'ImageDescription' => ASCII,    # Image title
 112                                         'Make' => ASCII,                # Image input equipment manufacturer
 113                                         'Model' => ASCII,               # Image input equipment model
 114                                         'Software' => ASCII,            # Software used
 115                                         'Artist' => ASCII,              # Person who created the image
 116                                         'Copyright' => ASCII,           # Copyright holder
 117                                 ),
 118                         ),
 119
 120                         # Exif IFD Attribute Information (p30-31)
 121                         'exif' => array(
 122                                 # Tags relating to version
 123                                 'version' => array(
 124                                         # TODO: NOTE: Nonexistence of this field is taken to mean nonconformance
 125                                         # to the EXIF 2.1 AND 2.2 standards
 126                                         'ExifVersion' => UNDEFINED,     # Exif version
 127                                         'FlashpixVersion' => UNDEFINED, # Supported Flashpix version #p32
 128                                 ),
 129
 130                                 # Tags relating to Image Data Characteristics
 131                                 'characteristics' => array(
 132                                         'ColorSpace' => SHORT,          # Color space information #p32
 133                                 ),
 134
 135                                 # Tags relating to image configuration
 136                                 'configuration' => array(
 137                                         'ComponentsConfiguration' => UNDEFINED,         # Meaning of each component #p33
 138                                         'CompressedBitsPerPixel' => RATIONAL,           # Image compression mode
 139                                         'PixelYDimension' => SHORT.','.LONG,            # Valid image width
 140                                         'PixelXDimension' => SHORT.','.LONG,            # Valind image height
 141                                 ),
 142
 143                                 # Tags relating to related user information
 144                                 'user' => array(
 145                                         'MakerNote' => UNDEFINED,                       # Manufacturer notes
 146                                         'UserComment' => UNDEFINED,                     # User comments #p34
 147                                 ),
 148
 149                                 # Tags relating to related file information
 150                                 'related' => array(
 151                                         'RelatedSoundFile' => ASCII,                    # Related audio file
 152                                 ),
 153
 154                                 # Tags relating to date and time
 155                                 'dateandtime' => array(
 156                                         'DateTimeOriginal' => ASCII,                    # Date and time of original data generation #p36
 157                                         'DateTimeDigitized' => ASCII,                   # Date and time of original data generation
 158                                         'SubSecTime' => ASCII,                          # DateTime subseconds
 159                                         'SubSecTimeOriginal' => ASCII,                  # DateTimeOriginal subseconds
 160                                         'SubSecTimeDigitized' => ASCII,                 # DateTimeDigitized subseconds
 161                                 ),
 162
 163                                 # Tags relating to picture-taking conditions (p31)
 164                                 'conditions' => array(
 165                                         'ExposureTime' => RATIONAL,                     # Exposure time
 166                                         'FNumber' => RATIONAL,                          # F Number
 167                                         'ExposureProgram' => SHORT,                     # Exposure Program #p38
 168                                         'SpectralSensitivity' => ASCII,                 # Spectral sensitivity
 169                                         'ISOSpeedRatings' => SHORT,                     # ISO speed rating
 170                                         'OECF' => UNDEFINED,                            # Optoelectronic conversion factor
 171                                         'ShutterSpeedValue' => SRATIONAL,               # Shutter speed
 172                                         'ApertureValue' => RATIONAL,                    # Aperture
 173                                         'BrightnessValue' => SRATIONAL,                 # Brightness
 174                                         'ExposureBiasValue' => SRATIONAL,               # Exposure bias
 175                                         'MaxApertureValue' => RATIONAL,                 # Maximum land aperture
 176                                         'SubjectDistance' => RATIONAL,                  # Subject distance
 177                                         'MeteringMode' => SHORT,                        # Metering mode #p40
 178                                         'LightSource' => SHORT,                         # Light source #p40-41
 179                                         'Flash' => SHORT,                               # Flash #p41-42
 180                                         'FocalLength' => RATIONAL,                      # Lens focal length
 181                                         'SubjectArea' => SHORT,                         # Subject area
 182                                         'FlashEnergy' => RATIONAL,                      # Flash energy
 183                                         'SpatialFrequencyResponse' => UNDEFINED,        # Spatial frequency response
 184                                         'FocalPlaneXResolution' => RATIONAL,            # Focal plane X resolution
 185                                         'FocalPlaneYResolution' => RATIONAL,            # Focal plane Y resolution
 186                                         'FocalPlaneResolutionUnit' => SHORT,            # Focal plane resolution unit
 187                                         'SubjectLocation' => SHORT,                     # Subject location
 188                                         'ExposureIndex' => RATIONAL,                    # Exposure index
 189                                         'SensingMethod' => SHORT,                       # Sensing method #p46
 190                                         'FileSource' => UNDEFINED,                      # File source #p47
 191                                         'SceneType' => UNDEFINED,                       # Scene type #p47
 192                                         'CFAPattern' => UNDEFINED,                      # CFA pattern
 193                                         'CustomRendered' => SHORT,                      # Custom image processing #p48
 194                                         'ExposureMode' => SHORT,                        # Exposure mode #p48
 195                                         'WhiteBalance' => SHORT,                        # White Balance #p49
 196                                         'DigitalZoomRatio' => RATIONAL,                 # Digital zoom ration
 197                                         'FocalLengthIn35mmFilm' => SHORT,               # Focal length in 35 mm film
 198                                         'SceneCaptureType' => SHORT,                    # Scene capture type #p49
 199                                         'GainControl' => RATIONAL,                      # Scene control #p49-50
 200                                         'Contrast' => SHORT,                            # Contrast #p50
 201                                         'Saturation' => SHORT,                          # Saturation #p50
 202                                         'Sharpness' => SHORT,                           # Sharpness #p50
 203                                         'DeviceSettingDescription' => UNDEFINED,        # Desice settings description
 204                                         'SubjectDistanceRange' => SHORT,                # Subject distance range #p51
 205                                 ),
 206
 207                                 'other' => array(
 208                                         'ImageUniqueID' => ASCII,       # Unique image ID
 209                                 ),
 210                         ),
 211
 212                         # GPS Attribute Information (p52)
 213                         'gps' => array(
 214                                 'GPSVersionID' => BYTE,                 # GPS tag version
 215                                 'GPSLatitudeRef' => ASCII,              # North or South Latitude #p52-53
 216                                 'GPSLatitude' => RATIONAL,              # Latitude
 217                                 'GPSLongitudeRef' => ASCII,             # East or West Longitude #p53
 218                                 'GPSLongitude' => RATIONAL,             # Longitude
 219                                 'GPSAltitudeRef' => BYTE,               # Altitude reference
 220                                 'GPSAltitude' => RATIONAL,              # Altitude
 221                                 'GPSTimeStamp' => RATIONAL,             # GPS time (atomic clock)
 222                                 'GPSSatellites' => ASCII,               # Satellites used for measurement
 223                                 'GPSStatus' => ASCII,                   # Receiver status #p54
 224                                 'GPSMeasureMode' => ASCII,              # Measurement mode #p54-55
 225                                 'GPSDOP' => RATIONAL,                   # Measurement precision
 226                                 'GPSSpeedRef' => ASCII,                 # Speed unit #p55
 227                                 'GPSSpeed' => RATIONAL,                 # Speed of GPS receiver
 228                                 'GPSTrackRef' => ASCII,                 # Reference for direction of movement #p55
 229                                 'GPSTrack' => RATIONAL,                 # Direction of movement
 230                                 'GPSImgDirectionRef' => ASCII,          # Reference for direction of image #p56
 231                                 'GPSImgDirection' => RATIONAL,          # Direction of image
 232                                 'GPSMapDatum' => ASCII,                 # Geodetic survey data used
 233                                 'GPSDestLatitudeRef' => ASCII,          # Reference for latitude of destination #p56
 234                                 'GPSDestLatitude' => RATIONAL,          # Latitude destination
 235                                 'GPSDestLongitudeRef' => ASCII,         # Reference for longitude of destination #p57
 236                                 'GPSDestLongitude' => RATIONAL,         # Longitude of destination
 237                                 'GPSDestBearingRef' => ASCII,           # Reference for bearing of destination #p57
 238                                 'GPSDestBearing' => RATIONAL,           # Bearing of destination
 239                                 'GPSDestDistanceRef' => ASCII,          # Reference for distance to destination #p57-58
 240                                 'GPSDestDistance' => RATIONAL,          # Distance to destination
 241                                 'GPSProcessingMethod' => UNDEFINED,     # Name of GPS processing method
 242                                 'GPSAreaInformation' => UNDEFINED,      # Name of GPS area
 243                                 'GPSDateStamp' => ASCII,                # GPS date
 244                                 'GPSDifferential' => SHORT,             # GPS differential correction
 245                         ),
 246                 );
 247
 248                 $this->makeFlatExifTags();
 249                 $this->makeValidExifTags();
 250         }
 251
 252         /**
 253          * Get the raw list of exiftags
 254          *
 255          * @access private
 256          * @return array
 257         */
 258         function getExif() {
 259                 return $this->mExif;
 260         }
 261
 262         /**
 263          * Generate a flat list of the exif tags
 264          */
 265         function makeFlatExifTags() {
 266                 $exif = $this->getExif();
 267                 array_walk($exif, array(&$this, 'callback')); // note the reference
 268         }
 269
 270         /**
 271          * A callback function used by makeFlatExifTags()
 272          */
 273         function callback($val, $key) {
 274                 if (gettype($val) === 'array')
 275                         array_walk($val, array(&$this, 'callback'));
 276                 else
 277                         $this->mFlatExif[$key] = $val;
 278         }
 279
 280         /**
 281          * Produce a list of all Exif tags appropriate for user output
 282          *
 283          * Produce a list of all tags that we want to show in output, in order not to
 284          * output binary gibberish such as raw thumbnails we strip all tags
 285          * with the datatype of UNDEFINED.
 286          *
 287          * @todo We might actually want to display some of the UNDEFINED
 288          *       stuff, but we strip it for now.
 289          */
 290         function makeValidExifTags() {
 291                 foreach($this->mFlatExif as $key => $val) {
 292                         if (strpos( $val, (string)UNDEFINED ) !== false)
 293                                 continue;
 294                         $this->mValidExif[] = $key;
 295                 }
 296         }
 297
 298          /**
 299           * The version of the output format
 300           *
 301           * Before the actual metadata information is saved in the database we
 302           * strip some of it since we don't want to save things like thumbnails
 303           * which usually accompany Exif data. This value gets saved in the
 304           * database along with the actual Exif data, and if the version in the
 305           * database doesn't equal the value returned by this function the Exif
 306           * data is regenerated.
 307           *
 308           * @return int
 309           */
 310         function version() {
 311                 return 1; // We don't need no bloddy constants!
 312         }
 313 }
 314 } // MEDIAWIKI