includes/resourceloader/ResourceLoaderLESSFunctions.php

   1 <?php
   2 /**
   3  * PHP-provided functions for LESS; see docs for $wgResourceLoaderLESSFunctions
   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  */
  22
  23 class ResourceLoaderLESSFunctions {
  24         /**
  25          * Check if an image file reference is suitable for embedding.
  26          * An image is embeddable if it (a) exists, (b) has a suitable MIME-type,
  27          * (c) does not exceed IE<9 size limit of 32kb. This is a LESS predicate
  28          * function; it returns a LESS boolean value and can thus be used as a
  29          * mixin guard.
  30          *
  31          * @par Example:
  32          * @code
  33          *   .background-image(@url) when(embeddable(@url)) {
  34          *       background-image: url(@url) !ie;
  35          *   }
  36          * @endcode
  37          */
  38         public static function embeddable( $frame, $less ) {
  39                 $base = pathinfo( $less->parser->sourceName, PATHINFO_DIRNAME );
  40                 $url = trim( $less->compileValue( $frame ), '"\'' );
  41                 $file = realpath( $base . '/' . $url );
  42                 return $less->toBool( $file
  43                         && strpos( $url, '//' ) === false
  44                         && filesize( $file ) < CSSMin::EMBED_SIZE_LIMIT
  45                         && CSSMin::getMimeType( $file ) !== false );
  46         }
  47
  48         /**
  49          * Convert an image URI to a base64-encoded data URI.
  50          *
  51          * @par Example:
  52          * @code
  53          *   .fancy-button {
  54          *       background-image: embed('../images/button-bg.png');
  55          *   }
  56          * @endcode
  57          */
  58         public static function embed( $frame, $less ) {
  59                 $base = pathinfo( $less->parser->sourceName, PATHINFO_DIRNAME );
  60                 $url = trim( $less->compileValue( $frame ), '"\'' );
  61                 $file = realpath( $base . '/' . $url );
  62
  63                 $data = CSSMin::encodeImageAsDataURI( $file );
  64                 $less->addParsedFile( $file );
  65                 return 'url(' . $data . ')';
  66         }
  67 }