public function getBarcodeSVG($w=3, $h=3, $color='black') {
		// send headers
		$code = $this->getBarcodeSVGcode($w, $h, $color);
		header('Content-Type: application/svg+xml');
		header('Cache-Control: public, must-revalidate, max-age=0'); // HTTP/1.1
		header('Pragma: public');
		header('Expires: Sat, 26 Jul 1997 05:00:00 GMT'); // Date in the past
		header('Last-Modified: '.gmdate('D, d M Y H:i:s').' GMT');
		header('Content-Disposition: inline; filename="'.md5($code).'.svg";');
		//header('Content-Length: '.strlen($code));
		echo $code;
	}