<?php

// needs picqer/php-barcode-generator

$generator = new \Picqer\Barcode\BarcodeGeneratorPNG();
$barcode = $generator->getBarcode($data, $generator::TYPE_CODE_128, 3, 100, [0,0,0]);

// ensure the char count is even for CODE_128_C
$barcodeData = (strlen($data) % 2)  === 0 ? $data : '0' . $data;
$generator = new \Picqer\Barcode\BarcodeGeneratorPNG();
$barcode = $generator->getBarcode($barcodeData, $generator::TYPE_CODE_128_C, 3, 100, [0,0,0]);