includes/ImageFunctions.php

   1 <?php
   2 /**
   3  * Return a rounded pixel equivalent for a labeled CSS/SVG length.
   4  * http://www.w3.org/TR/SVG11/coords.html#UnitIdentifiers
   5  *
   6  * @param $length String: CSS/SVG length.
   7  * @return Integer: length in pixels
   8  */
   9 function wfScaleSVGUnit( $length ) {
  10         static $unitLength = array(
  11                 'px' => 1.0,
  12                 'pt' => 1.25,
  13                 'pc' => 15.0,
  14                 'mm' => 3.543307,
  15                 'cm' => 35.43307,
  16                 'in' => 90.0,
  17                 ''   => 1.0, // "User units" pixels by default
  18                 '%'  => 2.0, // Fake it!
  19                 );
  20         $matches = array();
  21         if( preg_match( '/^(\d+(?:\.\d+)?)(em|ex|px|pt|pc|cm|mm|in|%|)$/', $length, $matches ) ) {
  22                 $length = floatval( $matches[1] );
  23                 $unit = $matches[2];
  24                 return round( $length * $unitLength[$unit] );
  25         } else {
  26                 // Assume pixels
  27                 return round( floatval( $length ) );
  28         }
  29 }
  30
  31 /**
  32  * Compatible with PHP getimagesize()
  33  * @todo support gzipped SVGZ
  34  * @todo check XML more carefully
  35  * @todo sensible defaults
  36  *
  37  * @param $filename String: full name of the file (passed to php fopen()).
  38  * @return array
  39  */
  40 function wfGetSVGsize( $filename ) {
  41         $width = 256;
  42         $height = 256;
  43
  44         // Read a chunk of the file
  45         $f = fopen( $filename, "rt" );
  46         if( !$f ) return false;
  47         $chunk = fread( $f, 4096 );
  48         fclose( $f );
  49
  50         // Uber-crappy hack! Run through a real XML parser.
  51         $matches = array();
  52         if( !preg_match( '/<svg\s*([^>]*)\s*>/s', $chunk, $matches ) ) {
  53                 return false;
  54         }
  55         $tag = $matches[1];
  56         if( preg_match( '/(?:^|\s)width\s*=\s*("[^"]+"|\'[^\']+\')/s', $tag, $matches ) ) {
  57                 $width = wfScaleSVGUnit( trim( substr( $matches[1], 1, -1 ) ) );
  58         }
  59         if( preg_match( '/(?:^|\s)height\s*=\s*("[^"]+"|\'[^\']+\')/s', $tag, $matches ) ) {
  60                 $height = wfScaleSVGUnit( trim( substr( $matches[1], 1, -1 ) ) );
  61         }
  62
  63         return array( $width, $height, 'SVG',
  64                 "width=\"$width\" height=\"$height\"" );
  65 }
  66
  67 /**
  68  * Determine if an image exists on the 'bad image list'.
  69  *
  70  * The format of MediaWiki:Bad_image_list is as follows:
  71  *    * Only list items (lines starting with "*") are considered
  72  *    * The first link on a line must be a link to a bad image
  73  *    * Any subsequent links on the same line are considered to be exceptions,
  74  *      i.e. articles where the image may occur inline.
  75  *
  76  * @param $name string the image name to check
  77  * @param $contextTitle Title: the page on which the image occurs, if known
  78  * @return bool
  79  */
  80 function wfIsBadImage( $name, $contextTitle = false ) {
  81         static $badImages = false;
  82         wfProfileIn( __METHOD__ );
  83
  84         # Run the extension hook
  85         $bad = false;
  86         if( !wfRunHooks( 'BadImage', array( $name, &$bad ) ) ) {
  87                 wfProfileOut( __METHOD__ );
  88                 return $bad;
  89         }
  90
  91         if( !$badImages ) {
  92                 # Build the list now
  93                 $badImages = array();
  94                 $lines = explode( "\n", wfMsgForContentNoTrans( 'bad_image_list' ) );
  95                 foreach( $lines as $line ) {
  96                         # List items only
  97                         if ( substr( $line, 0, 1 ) !== '*' ) {
  98                                 continue;
  99                         }
 100
 101                         # Find all links
 102                         $m = array();
 103                         if ( !preg_match_all( '/\[\[:?(.*?)\]\]/', $line, $m ) ) {
 104                                 continue;
 105                         }
 106
 107                         $exceptions = array();
 108                         $imageDBkey = false;
 109                         foreach ( $m[1] as $i => $titleText ) {
 110                                 $title = Title::newFromText( $titleText );
 111                                 if ( !is_null( $title ) ) {
 112                                         if ( $i == 0 ) {
 113                                                 $imageDBkey = $title->getDBkey();
 114                                         } else {
 115                                                 $exceptions[$title->getPrefixedDBkey()] = true;
 116                                         }
 117                                 }
 118                         }
 119
 120                         if ( $imageDBkey !== false ) {
 121                                 $badImages[$imageDBkey] = $exceptions;
 122                         }
 123                 }
 124         }
 125
 126         $contextKey = $contextTitle ? $contextTitle->getPrefixedDBkey() : false;
 127         $bad = isset( $badImages[$name] ) && !isset( $badImages[$name][$contextKey] );
 128         wfProfileOut( __METHOD__ );
 129         return $bad;
 130 }
 131
 132 /**
 133  * Calculate the largest thumbnail width for a given original file size
 134  * such that the thumbnail's height is at most $maxHeight.
 135  * @param $boxWidth Integer Width of the thumbnail box.
 136  * @param $boxHeight Integer Height of the thumbnail box.
 137  * @param $maxHeight Integer Maximum height expected for the thumbnail.
 138  * @return Integer.
 139  */
 140 function wfFitBoxWidth( $boxWidth, $boxHeight, $maxHeight ) {
 141         $idealWidth = $boxWidth * $maxHeight / $boxHeight;
 142         $roundedUp = ceil( $idealWidth );
 143         if( round( $roundedUp * $boxHeight / $boxWidth ) > $maxHeight )
 144                 return floor( $idealWidth );
 145         else
 146                 return $roundedUp;
 147 }