library/HTMLPurifier/TagTransform/Font.php

   1 <?php
   2
   3 /**
   4  * Transforms FONT tags to the proper form (SPAN with CSS styling)
   5  *
   6  * This transformation takes the three proprietary attributes of FONT and
   7  * transforms them into their corresponding CSS attributes.  These are color,
   8  * face, and size.
   9  *
  10  * @note Size is an interesting case because it doesn't map cleanly to CSS.
  11  *       Thanks to
  12  *       http://style.cleverchimp.com/font_size_intervals/altintervals.html
  13  *       for reasonable mappings.
  14  * @warning This doesn't work completely correctly; specifically, this
  15  *          TagTransform operates before well-formedness is enforced, so
  16  *          the "active formatting elements" algorithm doesn't get applied.
  17  */
  18 class HTMLPurifier_TagTransform_Font extends HTMLPurifier_TagTransform
  19 {
  20     /**
  21      * @type string
  22      */
  23     public $transform_to = 'span';
  24
  25     /**
  26      * @type array
  27      */
  28     protected $_size_lookup = array(
  29         '0' => 'xx-small',
  30         '1' => 'xx-small',
  31         '2' => 'small',
  32         '3' => 'medium',
  33         '4' => 'large',
  34         '5' => 'x-large',
  35         '6' => 'xx-large',
  36         '7' => '300%',
  37         '-1' => 'smaller',
  38         '-2' => '60%',
  39         '+1' => 'larger',
  40         '+2' => '150%',
  41         '+3' => '200%',
  42         '+4' => '300%'
  43     );
  44
  45     /**
  46      * @param HTMLPurifier_Token_Tag $tag
  47      * @param HTMLPurifier_Config $config
  48      * @param HTMLPurifier_Context $context
  49      * @return HTMLPurifier_Token_End|string
  50      */
  51     public function transform($tag, $config, $context)
  52     {
  53         if ($tag instanceof HTMLPurifier_Token_End) {
  54             $new_tag = clone $tag;
  55             $new_tag->name = $this->transform_to;
  56             return $new_tag;
  57         }
  58
  59         $attr = $tag->attr;
  60         $prepend_style = '';
  61
  62         // handle color transform
  63         if (isset($attr['color'])) {
  64             $prepend_style .= 'color:' . $attr['color'] . ';';
  65             unset($attr['color']);
  66         }
  67
  68         // handle face transform
  69         if (isset($attr['face'])) {
  70             $prepend_style .= 'font-family:' . $attr['face'] . ';';
  71             unset($attr['face']);
  72         }
  73
  74         // handle size transform
  75         if (isset($attr['size'])) {
  76             // normalize large numbers
  77             if ($attr['size'] !== '') {
  78                 if ($attr['size']{0} == '+' || $attr['size']{0} == '-') {
  79                     $size = (int)$attr['size'];
  80                     if ($size < -2) {
  81                         $attr['size'] = '-2';
  82                     }
  83                     if ($size > 4) {
  84                         $attr['size'] = '+4';
  85                     }
  86                 } else {
  87                     $size = (int)$attr['size'];
  88                     if ($size > 7) {
  89                         $attr['size'] = '7';
  90                     }
  91                 }
  92             }
  93             if (isset($this->_size_lookup[$attr['size']])) {
  94                 $prepend_style .= 'font-size:' .
  95                     $this->_size_lookup[$attr['size']] . ';';
  96             }
  97             unset($attr['size']);
  98         }
  99
 100         if ($prepend_style) {
 101             $attr['style'] = isset($attr['style']) ?
 102                 $prepend_style . $attr['style'] :
 103                 $prepend_style;
 104         }
 105
 106         $new_tag = clone $tag;
 107         $new_tag->name = $this->transform_to;
 108         $new_tag->attr = $attr;
 109
 110         return $new_tag;
 111     }
 112 }
 113
 114 // vim: et sw=4 sts=4