includes/media/PNG.php

   1 <?php
   2 /**
   3  * Handler for PNG images.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Media
  22  */
  23
  24 /**
  25  * Handler for PNG images.
  26  *
  27  * @ingroup Media
  28  */
  29 class PNGHandler extends BitmapHandler {
  30         const BROKEN_FILE = '0';
  31
  32         /**
  33          * @param File $image
  34          * @param string $filename
  35          * @return string
  36          */
  37         function getMetadata( $image, $filename ) {
  38                 try {
  39                         $metadata = BitmapMetadataHandler::PNG( $filename );
  40                 } catch ( Exception $e ) {
  41                         // Broken file?
  42                         wfDebug( __METHOD__ . ': ' . $e->getMessage() . "\n" );
  43
  44                         return self::BROKEN_FILE;
  45                 }
  46
  47                 return serialize( $metadata );
  48         }
  49
  50         /**
  51          * @param File $image
  52          * @return array|bool
  53          */
  54         function formatMetadata( $image ) {
  55                 $meta = $this->getCommonMetaArray( $image );
  56                 if ( count( $meta ) === 0 ) {
  57                         return false;
  58                 }
  59
  60                 return $this->formatMetadataHelper( $meta );
  61         }
  62
  63         /**
  64          * Get a file type independent array of metadata.
  65          *
  66          * @param File $image
  67          * @return array The metadata array
  68          */
  69         public function getCommonMetaArray( File $image ) {
  70                 $meta = $image->getMetadata();
  71
  72                 if ( !$meta ) {
  73                         return array();
  74                 }
  75                 $meta = unserialize( $meta );
  76                 if ( !isset( $meta['metadata'] ) ) {
  77                         return array();
  78                 }
  79                 unset( $meta['metadata']['_MW_PNG_VERSION'] );
  80
  81                 return $meta['metadata'];
  82         }
  83
  84         /**
  85          * @param File $image
  86          * @return bool
  87          */
  88         function isAnimatedImage( $image ) {
  89                 $ser = $image->getMetadata();
  90                 if ( $ser ) {
  91                         $metadata = unserialize( $ser );
  92                         if ( $metadata['frameCount'] > 1 ) {
  93                                 return true;
  94                         }
  95                 }
  96
  97                 return false;
  98         }
  99
 100         /**
 101          * We do not support making APNG thumbnails, so always false
 102          * @param File $image
 103          * @return bool False
 104          */
 105         function canAnimateThumbnail( $image ) {
 106                 return false;
 107         }
 108
 109         function getMetadataType( $image ) {
 110                 return 'parsed-png';
 111         }
 112
 113         function isMetadataValid( $image, $metadata ) {
 114
 115                 if ( $metadata === self::BROKEN_FILE ) {
 116                         // Do not repetitivly regenerate metadata on broken file.
 117                         return self::METADATA_GOOD;
 118                 }
 119
 120                 wfSuppressWarnings();
 121                 $data = unserialize( $metadata );
 122                 wfRestoreWarnings();
 123
 124                 if ( !$data || !is_array( $data ) ) {
 125                         wfDebug( __METHOD__ . " invalid png metadata\n" );
 126
 127                         return self::METADATA_BAD;
 128                 }
 129
 130                 if ( !isset( $data['metadata']['_MW_PNG_VERSION'] )
 131                         || $data['metadata']['_MW_PNG_VERSION'] != PNGMetadataExtractor::VERSION
 132                 ) {
 133                         wfDebug( __METHOD__ . " old but compatible png metadata\n" );
 134
 135                         return self::METADATA_COMPATIBLE;
 136                 }
 137
 138                 return self::METADATA_GOOD;
 139         }
 140
 141         /**
 142          * @param File $image
 143          * @return string
 144          */
 145         function getLongDesc( $image ) {
 146                 global $wgLang;
 147                 $original = parent::getLongDesc( $image );
 148
 149                 wfSuppressWarnings();
 150                 $metadata = unserialize( $image->getMetadata() );
 151                 wfRestoreWarnings();
 152
 153                 if ( !$metadata || $metadata['frameCount'] <= 0 ) {
 154                         return $original;
 155                 }
 156
 157                 $info = array();
 158                 $info[] = $original;
 159
 160                 if ( $metadata['loopCount'] == 0 ) {
 161                         $info[] = wfMessage( 'file-info-png-looped' )->parse();
 162                 } elseif ( $metadata['loopCount'] > 1 ) {
 163                         $info[] = wfMessage( 'file-info-png-repeat' )->numParams( $metadata['loopCount'] )->parse();
 164                 }
 165
 166                 if ( $metadata['frameCount'] > 0 ) {
 167                         $info[] = wfMessage( 'file-info-png-frames' )->numParams( $metadata['frameCount'] )->parse();
 168                 }
 169
 170                 if ( $metadata['duration'] ) {
 171                         $info[] = $wgLang->formatTimePeriod( $metadata['duration'] );
 172                 }
 173
 174                 return $wgLang->commaList( $info );
 175         }
 176
 177         // PNGs should be easy to support, but it will need some sharpening applied
 178         // and another user test to check if the perceived quality change is noticeable
 179
 180         public function supportsBucketing() {
 181                 return false;
 182         }
 183 }