The EAN8 barcode type is hardcoded in the reporting/rep303.php file in lines 327-329:
$barcode = str_pad($trans['stock_id'], 7, '0', STR_PAD_LEFT);
$barcode = substr($barcode, 0, 8); // EAN 8 Check digit is auto computed and barcode printed
$rep->write1DBarcode($barcode, 'EAN8', $rep->cols[$firstcol++], $bar_y + 22, 22, $SysPrefs->pic_height, 1.2, $style, 'N');
The default FA reporting/includes/barcodes.php file is from the TCPDF 's 1dBarcode library when used.
The reporting/rep303.php file however uses another library's extracted barcode functionality which supports only the following subset of formats:
EAN, EAN-8, EAN-13, GTIN-8, GTIN-12, GTIN-14, UPC, UPC-12 coupon code, JAN
Using another subset of TCPDF from a GitHub project for barcode generation is also feasible. This library is set to be PHP 5.4+ compatible but for backwards compatibility with PHP 5.3.x, just replace all instances of "= []" with "= Array()" in it's src/BarcodeGenerator.php file.
Sample code for using it in a standalone manner would be:
<?php
include('src/BarcodeGenerator.php');
include('src/BarcodeGeneratorPNG.php');
$generator = new Picqer\Barcode\BarcodeGeneratorPNG();
file_put_contents('src/files/081231723897-code128.png', $generator->getBarcode('081231723897', $generator::TYPE_CODE_128));
echo '<img src="data:image/png;base64,' . base64_encode($generator->getBarcode('081231723897', $generator::TYPE_CODE_128)) . '">';
The above will both generate a file and display it inline as well.