includes/ImageFunctions.php

   1 <?php
   2 /**
   3  * Global functions related to images
   4  *
   5  * @file
   6  */
   7
   8 /**
   9  * Return a rounded pixel equivalent for a labeled CSS/SVG length.
  10  * http://www.w3.org/TR/SVG11/coords.html#UnitIdentifiers
  11  *
  12  * @param $length String: CSS/SVG length.
  13  * @param $viewportSize: Float optional scale for percentage units...
  14  * @return float: length in pixels
  15  */
  16 function wfScaleSVGUnit( $length, $viewportSize=512 ) {
  17         static $unitLength = array(
  18                 'px' => 1.0,
  19                 'pt' => 1.25,
  20                 'pc' => 15.0,
  21                 'mm' => 3.543307,
  22                 'cm' => 35.43307,
  23                 'in' => 90.0,
  24                 'em' => 16.0, // fake it?
  25                 'ex' => 12.0, // fake it?
  26                 ''   => 1.0, // "User units" pixels by default
  27                 );
  28         $matches = array();
  29         if( preg_match( '/^\s*(\d+(?:\.\d+)?)(em|ex|px|pt|pc|cm|mm|in|%|)\s*$/', $length, $matches ) ) {
  30                 $length = floatval( $matches[1] );
  31                 $unit = $matches[2];
  32                 if( $unit == '%' ) {
  33                         return $length * 0.01 * $viewportSize;
  34                 } else {
  35                         return $length * $unitLength[$unit];
  36                 }
  37         } else {
  38                 // Assume pixels
  39                 return floatval( $length );
  40         }
  41 }
  42
  43 class XmlSizeFilter {
  44         const DEFAULT_WIDTH = 512;
  45         const DEFAULT_HEIGHT = 512;
  46         var $first = true;
  47         var $width = self::DEFAULT_WIDTH;
  48         var $height = self::DEFAULT_HEIGHT;
  49         function filter( $name, $attribs ) {
  50                 if( $this->first ) {
  51                         $defaultWidth = self::DEFAULT_WIDTH;
  52                         $defaultHeight = self::DEFAULT_HEIGHT;
  53                         $aspect = 1.0;
  54                         $width = null;
  55                         $height = null;
  56
  57                         if( isset( $attribs['viewBox'] ) ) {
  58                                 // min-x min-y width height
  59                                 $viewBox = preg_split( '/\s+/', trim( $attribs['viewBox'] ) );
  60                                 if( count( $viewBox ) == 4 ) {
  61                                         $viewWidth = wfScaleSVGUnit( $viewBox[2] );
  62                                         $viewHeight = wfScaleSVGUnit( $viewBox[3] );
  63                                         if( $viewWidth > 0 && $viewHeight > 0 ) {
  64                                                 $aspect = $viewWidth / $viewHeight;
  65                                                 $defaultHeight = $defaultWidth / $aspect;
  66                                         }
  67                                 }
  68                         }
  69                         if( isset( $attribs['width'] ) ) {
  70                                 $width = wfScaleSVGUnit( $attribs['width'], $defaultWidth );
  71                         }
  72                         if( isset( $attribs['height'] ) ) {
  73                                 $height = wfScaleSVGUnit( $attribs['height'], $defaultHeight );
  74                         }
  75
  76                         if( !isset( $width ) && !isset( $height ) ) {
  77                                 $width = $defaultWidth;
  78                                 $height = $width / $aspect;
  79                         } elseif( isset( $width ) && !isset( $height ) ) {
  80                                 $height = $width / $aspect;
  81                         } elseif( isset( $height ) && !isset( $width ) ) {
  82                                 $width = $height * $aspect;
  83                         }
  84
  85                         if( $width > 0 && $height > 0 ) {
  86                                 $this->width = intval( round( $width ) );
  87                                 $this->height = intval( round( $height ) );
  88                         }
  89
  90                         $this->first = false;
  91                 }
  92         }
  93 }
  94
  95 /**
  96  * Compatible with PHP getimagesize()
  97  * @todo support gzipped SVGZ
  98  * @todo check XML more carefully
  99  * @todo sensible defaults
 100  *
 101  * @param $filename String: full name of the file (passed to php fopen()).
 102  * @return array
 103  */
 104 function wfGetSVGsize( $filename ) {
 105         $filter = new XmlSizeFilter();
 106         $xml = new XmlTypeCheck( $filename, array( $filter, 'filter' ) );
 107         if( $xml->wellFormed ) {
 108                 return array( $filter->width, $filter->height, 'SVG',
 109                         "width=\"$filter->width\" height=\"$filter->height\"" );
 110         }
 111
 112         return false;
 113 }
 114
 115 /**
 116  * Determine if an image exists on the 'bad image list'.
 117  *
 118  * The format of MediaWiki:Bad_image_list is as follows:
 119  *    * Only list items (lines starting with "*") are considered
 120  *    * The first link on a line must be a link to a bad image
 121  *    * Any subsequent links on the same line are considered to be exceptions,
 122  *      i.e. articles where the image may occur inline.
 123  *
 124  * @param $name string the image name to check
 125  * @param $contextTitle Title: the page on which the image occurs, if known
 126  * @return bool
 127  */
 128 function wfIsBadImage( $name, $contextTitle = false ) {
 129         static $badImages = false;
 130         wfProfileIn( __METHOD__ );
 131
 132         # Handle redirects
 133         $redirectTitle = RepoGroup::singleton()->checkRedirect( Title::makeTitle( NS_FILE, $name ) );
 134         if( $redirectTitle ) {
 135                 $name = $redirectTitle->getDbKey();
 136         }
 137
 138         # Run the extension hook
 139         $bad = false;
 140         if( !wfRunHooks( 'BadImage', array( $name, &$bad ) ) ) {
 141                 wfProfileOut( __METHOD__ );
 142                 return $bad;
 143         }
 144
 145         if( !$badImages ) {
 146                 # Build the list now
 147                 $badImages = array();
 148                 $lines = explode( "\n", wfMsgForContentNoTrans( 'bad_image_list' ) );
 149                 foreach( $lines as $line ) {
 150                         # List items only
 151                         if ( substr( $line, 0, 1 ) !== '*' ) {
 152                                 continue;
 153                         }
 154
 155                         # Find all links
 156                         $m = array();
 157                         if ( !preg_match_all( '/\[\[:?(.*?)\]\]/', $line, $m ) ) {
 158                                 continue;
 159                         }
 160
 161                         $exceptions = array();
 162                         $imageDBkey = false;
 163                         foreach ( $m[1] as $i => $titleText ) {
 164                                 $title = Title::newFromText( $titleText );
 165                                 if ( !is_null( $title ) ) {
 166                                         if ( $i == 0 ) {
 167                                                 $imageDBkey = $title->getDBkey();
 168                                         } else {
 169                                                 $exceptions[$title->getPrefixedDBkey()] = true;
 170                                         }
 171                                 }
 172                         }
 173
 174                         if ( $imageDBkey !== false ) {
 175                                 $badImages[$imageDBkey] = $exceptions;
 176                         }
 177                 }
 178         }
 179
 180         $contextKey = $contextTitle ? $contextTitle->getPrefixedDBkey() : false;
 181         $bad = isset( $badImages[$name] ) && !isset( $badImages[$name][$contextKey] );
 182         wfProfileOut( __METHOD__ );
 183         return $bad;
 184 }
 185
 186 /**
 187  * Calculate the largest thumbnail width for a given original file size
 188  * such that the thumbnail's height is at most $maxHeight.
 189  * @param $boxWidth Integer Width of the thumbnail box.
 190  * @param $boxHeight Integer Height of the thumbnail box.
 191  * @param $maxHeight Integer Maximum height expected for the thumbnail.
 192  * @return Integer.
 193  */
 194 function wfFitBoxWidth( $boxWidth, $boxHeight, $maxHeight ) {
 195         $idealWidth = $boxWidth * $maxHeight / $boxHeight;
 196         $roundedUp = ceil( $idealWidth );
 197         if( round( $roundedUp * $boxHeight / $boxWidth ) > $maxHeight )
 198                 return floor( $idealWidth );
 199         else
 200                 return $roundedUp;
 201 }