QR code generating library with HTML/PNG/mPDF output possibilities.
This is based on QrCode library bundled with mPDF until v8.0, made by Laurent Minguet. It is provided under LGPL license.
$ composer require mpdf/qrcode
<?php
use Mpdf\QrCode\QrCode;
use Mpdf\QrCode\Output;
$qrCode = new QrCode('Lorem ipsum sit dolor');
$output = new Output\Png();
// Save black on white PNG image 100px wide to filename.png
$output->output($qrCode, 100, [255, 255, 255], [0, 0, 0], 'filename.png');