make base color darker by a specified factor

gistfile1.txt

function hex_darker($hex, $factor = 30)
{
	$new_hex = '';
	
	$base['R'] = hexdec($hex{0}.$hex{1});
	$base['G'] = hexdec($hex{2}.$hex{3});
	$base['B'] = hexdec($hex{4}.$hex{5});
	
	foreach ($base as $k => $v)
	{
		$amount = $v / 100;
		$amount = round($amount * $factor);
		$new_decimal = $v - $amount;
		
		$new_hex_component = dechex($new_decimal);
		if (strlen($new_hex_component) < 2) { 
			$new_hex_component = "0".$new_hex_component; 
		}
		$new_hex .= $new_hex_component;
	}
	
	return $new_hex;        
}