includes/media/XCF.php

   1 <?php
   2 /**
   3  * Handler for the Gimp's native file format (XCF)
   4  *
   5  * Overview:
   6  *   http://en.wikipedia.org/wiki/XCF_(file_format)
   7  * Specification in Gnome repository:
   8  *   http://svn.gnome.org/viewvc/gimp/trunk/devel-docs/xcf.txt?view=markup
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License along
  21  * with this program; if not, write to the Free Software Foundation, Inc.,
  22  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  23  * http://www.gnu.org/copyleft/gpl.html
  24  *
  25  * @file
  26  * @ingroup Media
  27  */
  28
  29 /**
  30  * Handler for the Gimp's native file format; getimagesize() doesn't
  31  * support these files
  32  *
  33  * @ingroup Media
  34  */
  35 class XCFHandler extends BitmapHandler {
  36
  37         /**
  38          * @param $file
  39          * @return bool
  40          */
  41         function mustRender( $file ) {
  42                 return true;
  43         }
  44
  45         /**
  46          * Render files as PNG
  47          *
  48          * @param $ext
  49          * @param $mime
  50          * @param $params
  51          * @return array
  52          */
  53         function getThumbType( $ext, $mime, $params = null ) {
  54                 return array( 'png', 'image/png' );
  55         }
  56
  57         /**
  58          * Get width and height from the XCF header.
  59          *
  60          * @param $image
  61          * @param $filename
  62          * @return array
  63          */
  64         function getImageSize( $image, $filename ) {
  65                 return self::getXCFMetaData( $filename );
  66         }
  67
  68         /**
  69          * Metadata for a given XCF file
  70          *
  71          * Will return false if file magic signature is not recognized
  72          * @author Hexmode
  73          * @author Hashar
  74          *
  75          * @param string $filename Full path to a XCF file
  76          * @return bool|array metadata array just like PHP getimagesize()
  77          */
  78         static function getXCFMetaData( $filename ) {
  79                 # Decode master structure
  80                 $f = fopen( $filename, 'rb' );
  81                 if ( !$f ) {
  82                         return false;
  83                 }
  84                 # The image structure always starts at offset 0 in the XCF file.
  85                 # So we just read it :-)
  86                 $binaryHeader = fread( $f, 26 );
  87                 fclose( $f );
  88
  89                 # Master image structure:
  90                 #
  91                 # byte[9] "gimp xcf "  File type magic
  92                 # byte[4] version      XCF version
  93                 #                        "file" - version 0
  94                 #                        "v001" - version 1
  95                 #                        "v002" - version 2
  96                 # byte    0            Zero-terminator for version tag
  97                 # uint32  width        With of canvas
  98                 # uint32  height       Height of canvas
  99                 # uint32  base_type    Color mode of the image; one of
 100                 #                         0: RGB color
 101                 #                         1: Grayscale
 102                 #                         2: Indexed color
 103                 #        (enum GimpImageBaseType in libgimpbase/gimpbaseenums.h)
 104                 try {
 105                         $header = wfUnpack(
 106                                   "A9magic"     # A: space padded
 107                                 . "/a5version"  # a: zero padded
 108                                 . "/Nwidth"     # \
 109                                 . "/Nheight"    # N: unsigned long 32bit big endian
 110                                 . "/Nbase_type" # /
 111                         , $binaryHeader
 112                         );
 113                 } catch ( MWException $mwe ) {
 114                         return false;
 115                 }
 116
 117                 # Check values
 118                 if ( $header['magic'] !== 'gimp xcf' ) {
 119                         wfDebug( __METHOD__ . " '$filename' has invalid magic signature.\n" );
 120                         return false;
 121                 }
 122                 # TODO: we might want to check for sane values of width and height
 123
 124                 wfDebug( __METHOD__ . ": canvas size of '$filename' is {$header['width']} x {$header['height']} px\n" );
 125
 126                 # Forge a return array containing metadata information just like getimagesize()
 127                 # See PHP documentation at: http://www.php.net/getimagesize
 128                 $metadata = array();
 129                 $metadata[0] = $header['width'];
 130                 $metadata[1] = $header['height'];
 131                 $metadata[2] = null;   # IMAGETYPE constant, none exist for XCF.
 132                 $metadata[3] = sprintf(
 133                         'height="%s" width="%s"', $header['height'], $header['width']
 134                 );
 135                 $metadata['mime'] = 'image/x-xcf';
 136                 $metadata['channels'] = null;
 137                 $metadata['bits'] = 8;  # Always 8-bits per color
 138
 139                 assert( '7 == count($metadata); # return array must contains 7 elements just like getimagesize() return' );
 140
 141                 return $metadata;
 142         }
 143
 144         /**
 145          * Must use "im" for XCF
 146          *
 147          * @return string
 148          */
 149         protected static function getScalerType( $dstPath, $checkDstPath = true ) {
 150                 return "im";
 151         }
 152 }