<?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_CSS_BackgroundPosition extends HTMLPurifier_AttrDef
{
/**
* @type HTMLPurifier_AttrDef_CSS_Length
*/
protected $length;
/**
* @type HTMLPurifier_AttrDef_CSS_Percentage
*/
protected $percentage;
public function __construct()
{
$this->length = new HTMLPurifier_AttrDef_CSS_Length();
$this->percentage = new HTMLPurifier_AttrDef_CSS_Percentage();
}
/**
* @param string $string
* @param HTMLPurifier_Config $config
* @param HTMLPurifier_Context $context
* @return bool|string
*/
public function validate($string, $config, $context)
{
$string = $this->parseCDATA($string);
$bits = explode(' ', $string);
$keywords = array();
$keywords['h'] = false; // left, right
$keywords['v'] = false; // top, bottom
$keywords['ch'] = false; // center (first word)
$keywords['cv'] = false; // center (second word)
$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];
if ($status == 'c') {
if ($i == 0) {
$status = 'ch';
} else {
$status = 'cv';
}
}
$keywords[$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[] = $keywords['h'];
} elseif ($keywords['ch']) {
$ret[] = $keywords['ch'];
$keywords['cv'] = false; // prevent re-use: center = center center
} elseif (count($measures)) {
$ret[] = array_shift($measures);
}
if ($keywords['v']) {
$ret[] = $keywords['v'];
} elseif ($keywords['cv']) {
$ret[] = $keywords['cv'];
} elseif (count($measures)) {
$ret[] = array_shift($measures);
}
if (empty($ret)) {
return false;
}
return implode(' ', $ret);
}
}
// vim: et sw=4 sts=4