Hello.
I tested this plugin in your demo site.
https://zeroqode-demo-07.bubbleapps.io/barcode_2_demo
My smartphone (HUAWEI P20 Pro, Android 9, Chrome 74.0.3729.136) can scarcely read QR Code image with “QR & Bar Code Reader” because the camera is out of focus.
I guess this plugin forcibly use the telescope lens of smartphone when reading QR or Bar Code. It is 10x zoom. (It has 1x lens, 3x lens and 10x lens (degital zoom of 3x lens) ) Therefore, it cannot be out of focus because the distance to the images is too short.
Can I resolve the issue with setting any parameters when I purchase it and install?