Can this support make png file which has transparent alpha to a transparent pdf file

[jonny77]

require DIR . '/vendor/autoload.php';
use Jcupitt\Vips;

$image = Vips\Image::newFromFile('./images/demo.png', ['access' => 'sequential']);

$image->writeToFile('./aa.pdf', [
//'format' => 'pdf'
]);
not working and got error
VipsForeignSave: "./aa.pdf" is not a known file format

[jcupitt]

Sorry, libvips does not support PDF write.