[1.4.0] CSS property background-position implemented. Also:

- Fixed some misinformation in Percentage
- Add support for lowercase CSS length units

git-svn-id: http://htmlpurifier.org/svnroot/htmlpurifier/trunk@661 48356398-32a2-884e-a903-53898d9a118a

library/HTMLPurifier/AttrDef/BackgroundPosition.php

@@ -0,0 +1,130 @@
+<?php
+
+require_once 'HTMLPurifier/AttrDef.php';
+require_once 'HTMLPurifier/AttrDef/CSSLength.php';
+require_once 'HTMLPurifier/AttrDef/Percentage.php';
+
+/* W3C says:
+    [ // adjective and number must be in correct order, even if
+      // you could switch them without introducing ambiguity.
+      // some browsers support that syntax
+        [
+            <percentage> | <length> | left | center | right
+        ]
+        [ 
+            <percentage> | <length> | top | center | bottom
+        ]?
+    ] |
+    [ // this signifies that the vertical and horizontal adjectives
+      // can be arbitrarily ordered, however, there can only be two,
+      // one of each, or none at all
+        [
+            left | center | right
+        ] ||
+        [
+            top | center | bottom
+        ]
+    ]
+    top, left = 0%
+    center, (none) = 50%
+    bottom, right = 100%
+*/
+
+/* QuirksMode says:
+    keyword + length/percentage must be ordered correctly, as per W3C
+    
+    Internet Explorer and Opera, however, support arbitrary ordering. We
+    should fix it up.
+    
+    Minor issue though, not strictly necessary.
+*/
+
+// control freaks may appreciate the ability to convert these to
+// percentages or something, but it's not necessary
+
+/**
+ * Validates the value of background-position.
+ */
+class HTMLPurifier_AttrDef_BackgroundPosition extends HTMLPurifier_AttrDef
+{
+    
+    var $length;
+    var $percentage;
+    
+    function HTMLPurifier_AttrDef_BackgroundPosition() {
+        $this->length     = new HTMLPurifier_AttrDef_CSSLength();
+        $this->percentage = new HTMLPurifier_AttrDef_Percentage();
+    }
+    
+    function validate($string, $config, &$context) {
+        $string = $this->parseCDATA($string);
+        $bits = explode(' ', $string);
+        
+        $keywords = array();
+        $keywords['h'] = false; // left, right
+        $keywords['v'] = false; // top, bottom
+        $keywords['c'] = false; // center
+        $measures = array();
+        
+        $i = 0;
+        
+        $lookup = array(
+            'top' => 'v',
+            'bottom' => 'v',
+            'left' => 'h',
+            'right' => 'h',
+            'center' => 'c'
+        );
+        
+        foreach ($bits as $bit) {
+            if ($bit === '') continue;
+            
+            // test for keyword
+            $lbit = ctype_lower($bit) ? $bit : strtolower($bit);
+            if (isset($lookup[$lbit])) {
+                $status = $lookup[$lbit];
+                $keywords[$status] = $lbit;
+                $i++;
+            }
+            
+            // test for length
+            $r = $this->length->validate($bit, $config, &$context);
+            if ($r !== false) {
+                $measures[] = $r;
+                $i++;
+            }
+            
+            // test for percentage
+            $r = $this->percentage->validate($bit, $config, &$context);
+            if ($r !== false) {
+                $measures[] = $r;
+                $i++;
+            }
+            
+        }
+        
+        if (!$i) return false; // no valid values were caught
+        
+        
+        $ret = array();
+        
+        // first keyword
+        if     ($keywords['h'])     $ret[] = $keywords['h'];
+        elseif (count($measures))   $ret[] = array_shift($measures);
+        elseif ($keywords['c']) {
+            $ret[] = $keywords['c'];
+            $keywords['c'] = false; // prevent re-use: center = center center
+        }
+        
+        if     ($keywords['v'])     $ret[] = $keywords['v'];
+        elseif (count($measures))   $ret[] = array_shift($measures);
+        elseif ($keywords['c'])     $ret[] = $keywords['c'];
+        
+        if (empty($ret)) return false;
+        return implode(' ', $ret);
+        
+    }
+    
+}
+
+?>

library/HTMLPurifier/AttrDef/CSSLength.php

@@ -40,6 +40,7 @@ class HTMLPurifier_AttrDef_CSSLength extends HTMLPurifier_AttrDef
         
         // we assume all units are two characters
         $unit = substr($length, $strlen - 2);
+        if (!ctype_lower($unit)) $unit = strtolower($unit);
         $number = substr($length, 0, $strlen - 2);
         
         if (!isset($this->units[$unit])) return false;

library/HTMLPurifier/AttrDef/Percentage.php

@@ -4,14 +4,13 @@ require_once 'HTMLPurifier/AttrDef.php';
 require_once 'HTMLPurifier/AttrDef/Number.php';
 
 /**
- * Validates a Percentage as defined by the HTML spec.
- * @note This also allows integer pixel values.
+ * Validates a Percentage as defined by the CSS spec.
  */
 class HTMLPurifier_AttrDef_Percentage extends HTMLPurifier_AttrDef
 {
     
     /**
-     * Instance of HTMLPurifier_AttrDef_Number to defer pixel validation
+     * Instance of HTMLPurifier_AttrDef_Number to defer number validation
      */
     var $number_def;
     

library/HTMLPurifier/CSSDefinition.php

@@ -79,6 +79,7 @@ class HTMLPurifier_CSSDefinition
         $this->info['background-attachment'] = new HTMLPurifier_AttrDef_Enum(
             array('scroll', 'fixed')
         );
+        $this->info['background-position'] = new HTMLPurifier_AttrDef_BackgroundPosition();
         
         // pending its own validator as a shorthand
         $this->info['background'] =