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  * @param $viewportSize: Float optional scale for percentage units...
   8  * @return float: length in pixels
   9  */
  10 function wfScaleSVGUnit( $length, $viewportSize=512 ) {
  11         static $unitLength = array(
  12                 'px' => 1.0,
  13                 'pt' => 1.25,
  14                 'pc' => 15.0,
  15                 'mm' => 3.543307,
  16                 'cm' => 35.43307,
  17                 'in' => 90.0,
  18                 'em' => 16.0, // fake it?
  19                 'ex' => 12.0, // fake it?
  20                 ''   => 1.0, // "User units" pixels by default
  21                 );
  22         $matches = array();
  23         if( preg_match( '/^\s*(\d+(?:\.\d+)?)(em|ex|px|pt|pc|cm|mm|in|%|)\s*$/', $length, $matches ) ) {
  24                 $length = floatval( $matches[1] );
  25                 $unit = $matches[2];
  26                 if( $unit == '%' ) {
  27                         return $length * 0.01 * $viewportSize;
  28                 } else {
  29                         return $length * $unitLength[$unit];
  30                 }
  31         } else {
  32                 // Assume pixels
  33                 return floatval( $length );
  34         }
  35 }
  36
  37 class XmlSizeFilter {
  38         const DEFAULT_WIDTH = 512;
  39         const DEFAULT_HEIGHT = 512;
  40         var $first = true;
  41         var $width = self::DEFAULT_WIDTH;
  42         var $height = self::DEFAULT_HEIGHT;
  43         function filter( $name, $attribs ) {
  44                 if( $this->first ) {
  45                         $defaultWidth = self::DEFAULT_WIDTH;
  46                         $defaultHeight = self::DEFAULT_HEIGHT;
  47                         $aspect = 1.0;
  48                         $width = null;
  49                         $height = null;
  50
  51                         if( isset( $attribs['viewBox'] ) ) {
  52                                 // min-x min-y width height
  53                                 $viewBox = preg_split( '/\s+/', trim( $attribs['viewBox'] ) );
  54                                 if( count( $viewBox ) == 4 ) {
  55                                         $viewWidth = wfScaleSVGUnit( $viewBox[2] );
  56                                         $viewHeight = wfScaleSVGUnit( $viewBox[3] );
  57                                         if( $viewWidth > 0 && $viewHeight > 0 ) {
  58                                                 $aspect = $viewWidth / $viewHeight;
  59                                                 $defaultHeight = $defaultWidth / $aspect;
  60                                         }
  61                                 }
  62                         }
  63                         if( isset( $attribs['width'] ) ) {
  64                                 $width = wfScaleSVGUnit( $attribs['width'], $defaultWidth );
  65                         }
  66                         if( isset( $attribs['height'] ) ) {
  67                                 $height = wfScaleSVGUnit( $attribs['height'], $defaultHeight );
  68                         }
  69
  70                         if( !isset( $width ) && !isset( $height ) ) {
  71                                 $width = $defaultWidth;
  72                                 $height = $width / $aspect;
  73                         } elseif( isset( $width ) && !isset( $height ) ) {
  74                                 $height = $width / $aspect;
  75                         } elseif( isset( $height ) && !isset( $width ) ) {
  76                                 $width = $height * $aspect;
  77                         }
  78
  79                         if( $width > 0 && $height > 0 ) {
  80                                 $this->width = intval( round( $width ) );
  81                                 $this->height = intval( round( $height ) );
  82                         }
  83
  84                         $this->first = false;
  85                 }
  86         }
  87 }
  88
  89 /**
  90  * Compatible with PHP getimagesize()
  91  * @todo support gzipped SVGZ
  92  * @todo check XML more carefully
  93  * @todo sensible defaults
  94  *
  95  * @param $filename String: full name of the file (passed to php fopen()).
  96  * @return array
  97  */
  98 function wfGetSVGsize( $filename ) {
  99         $filter = new XmlSizeFilter();
 100         $xml = new XmlTypeCheck( $filename, array( $filter, 'filter' ) );
 101         if( $xml->wellFormed ) {
 102                 return array( $filter->width, $filter->height, 'SVG',
 103                         "width=\"$filter->width\" height=\"$filter->height\"" );
 104         }
 105
 106         return false;
 107 }
 108
 109 /**
 110  * Determine if an image exists on the 'bad image list'.
 111  *
 112  * The format of MediaWiki:Bad_image_list is as follows:
 113  *    * Only list items (lines starting with "*") are considered
 114  *    * The first link on a line must be a link to a bad image
 115  *    * Any subsequent links on the same line are considered to be exceptions,
 116  *      i.e. articles where the image may occur inline.
 117  *
 118  * @param $name string the image name to check
 119  * @param $contextTitle Title: the page on which the image occurs, if known
 120  * @return bool
 121  */
 122 function wfIsBadImage( $name, $contextTitle = false ) {
 123         static $badImages = false;
 124         wfProfileIn( __METHOD__ );
 125
 126         # Run the extension hook
 127         $bad = false;
 128         if( !wfRunHooks( 'BadImage', array( $name, &$bad ) ) ) {
 129                 wfProfileOut( __METHOD__ );
 130                 return $bad;
 131         }
 132
 133         if( !$badImages ) {
 134                 # Build the list now
 135                 $badImages = array();
 136                 $lines = explode( "\n", wfMsgForContentNoTrans( 'bad_image_list' ) );
 137                 foreach( $lines as $line ) {
 138                         # List items only
 139                         if ( substr( $line, 0, 1 ) !== '*' ) {
 140                                 continue;
 141                         }
 142
 143                         # Find all links
 144                         $m = array();
 145                         if ( !preg_match_all( '/\[\[:?(.*?)\]\]/', $line, $m ) ) {
 146                                 continue;
 147                         }
 148
 149                         $exceptions = array();
 150                         $imageDBkey = false;
 151                         foreach ( $m[1] as $i => $titleText ) {
 152                                 $title = Title::newFromText( $titleText );
 153                                 if ( !is_null( $title ) ) {
 154                                         if ( $i == 0 ) {
 155                                                 $imageDBkey = $title->getDBkey();
 156                                         } else {
 157                                                 $exceptions[$title->getPrefixedDBkey()] = true;
 158                                         }
 159                                 }
 160                         }
 161
 162                         if ( $imageDBkey !== false ) {
 163                                 $badImages[$imageDBkey] = $exceptions;
 164                         }
 165                 }
 166         }
 167
 168         $contextKey = $contextTitle ? $contextTitle->getPrefixedDBkey() : false;
 169         $bad = isset( $badImages[$name] ) && !isset( $badImages[$name][$contextKey] );
 170         wfProfileOut( __METHOD__ );
 171         return $bad;
 172 }
 173
 174 /**
 175  * Calculate the largest thumbnail width for a given original file size
 176  * such that the thumbnail's height is at most $maxHeight.
 177  * @param $boxWidth Integer Width of the thumbnail box.
 178  * @param $boxHeight Integer Height of the thumbnail box.
 179  * @param $maxHeight Integer Maximum height expected for the thumbnail.
 180  * @return Integer.
 181  */
 182 function wfFitBoxWidth( $boxWidth, $boxHeight, $maxHeight ) {
 183         $idealWidth = $boxWidth * $maxHeight / $boxHeight;
 184         $roundedUp = ceil( $idealWidth );
 185         if( round( $roundedUp * $boxHeight / $boxWidth ) > $maxHeight )
 186                 return floor( $idealWidth );
 187         else
 188                 return $roundedUp;
 189 }