AddEventHandler('main', 'OnEndBufferContent', array('NlOnEndBufferContent', 'ChangeMyContent'));

require_once $_SERVER['DOCUMENT_ROOT'].'/bitrix/templates/.pdf/dompdf/autoload.inc.php';
Dompdf\Autoloader::register();
use Dompdf\Dompdf;

class NlOnEndBufferContent
{
    function ChangeMyContent($content){
        if($_REQUEST['pdf']=='y'){



            define("DOMPDF_ENABLE_REMOTE", false);


            $dompdf = new Dompdf();
            $dompdf->set_option('defaultFont', 'dejavu sans');
            $dompdf->loadHtml($content,"UTF-8");
            $dompdf->setPaper('A4', 'portrait');
            $dompdf->render();
            $dompdf->stream();
        }

    }

}