The endroid/QrCode library is easy to use, well maintained, and can be installed using composer. There is also a bundle to use directly with Symfony.
Installing :
$ composer require endroid/qrcode
Usage :
<?php
use Endroid\QrCode\QrCode;
$qrCode = new QrCode();
$qrCode
->setText('Life is too short to be generating QR codes')
->setSize(300)
->setPadding(10)
->setErrorCorrection('high')
->setForegroundColor(array('r' => 0, 'g' => 0, 'b' => 0, 'a' => 0))
->setBackgroundColor(array('r' => 255, 'g' => 255, 'b' => 255, 'a' => 0))
->setLabel('Scan the code')
->setLabelFontSize(16)
->setImageType(QrCode::IMAGE_TYPE_PNG)
;
// now we can directly output the qrcode
header('Content-Type: '.$qrCode->getContentType());
$qrCode->render();
// or create a response object
$response = new Response($qrCode->get(), 200, array('Content-Type' => $qrCode->getContentType()));
