dompdf part 2 and 3

<?php
require_once 'dompdf/autoload.inc.php';

// reference the Dompdf namespace
use Dompdf\Dompdf;

// instantiate and use the dompdf class
$dompdf = new Dompdf();
$dompdf->loadHtml(file_get_contents('sample.html'));

// (Optional) Setup the paper size and orientation
$dompdf->setPaper(array(0,0,850,1600), 'landscape');

// Render the HTML as PDF
$dompdf->render();

// Output the generated PDF to Browser
$dompdf->stream("samplepdf1");
?>

This shows that it can only generate pdf of the file that exists inside the directory. It is possible to get the pdf by entering any URL?