get pdf file path, return pdf first page preview

function getPdfPreView($pdfPath) {
    $pdf = new \Zend_Pdf();
    $pdf->load($pdfPath);
    $pdf->saveImage($pdfPath . '.jpg', 0);
    return $pdfPath . '.jpg';
}

$pdfPath = './test.pdf';
$preViewPath = getPdfPreView($pdfPath);