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<?php
/**
* This class defines the Horde_Image:: API, and also provides some
* utility functions, such as generating highlights of a color.
*
* $Horde: horde/lib/Image.php,v 1.1.2.1 2003/02/27 17:53:44 chuck Exp $
*
* Copyright 2002-2003 Chuck Hagenbuch <chuck@horde.org>
*
* See the enclosed file COPYING for license information (LGPL). If you
* did not receive this file, see http://www.fsf.org/copyleft/lgpl.html.
*
* @author Chuck Hagenbuch <chuck@horde.org>
* @version $Revision: 1.1.2.1 $
* @since Horde 3.0
* @package horde.image
*/
class Horde_Image {
/**
* Calculate a lighter (or darker) version of a color.
*
* @param string $color An HTML color, e.g.: #ffffcc.
*
* @return string A modified HTML color.
*/
function modifyColor($color, $factor = 0x11)
{
$r = hexdec(substr($color, 1, 2));
$g = hexdec(substr($color, 3, 2));
$b = hexdec(substr($color, 5, 2));
if ($r >= $g && $r >= $b) {
$g = $g / $r;
$b = $b / $r;
$r = $r + $factor;
$g = floor($g * $r);
$b = floor($b * $r);
} elseif ($g >= $r && $g >= $b) {
$r = $r / $g;
$b = $b / $g;
$g = $g + $factor;
$r = floor($r * $g);
$b = floor($b * $g);
} else {
$r = $r / $b;
$g = $g / $b;
$b = $b + $factor;
$r = floor($r * $b);
$g = floor($g * $b);
}
return '#' . str_pad(dechex(min($r, 255)), 2, '0', STR_PAD_LEFT) . str_pad(dechex(min($g, 255)), 2, '0', STR_PAD_LEFT) . str_pad(dechex(min($b, 255)), 2, '0', STR_PAD_LEFT);
}
}
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