[cups-devel] Capture raw print data, append QR code before sending to printer

I am trying to intercept raw print data stream from a POS system, modify it
before sending it to a networked Epson thermal receipt printer as described
below:


i) Intercept print data,

ii) use the data to encode a QR code,

iii) append it to the captured data,

iv) send to printer


I have limited knowledge on linux and CUPS. Appreciate if someone could
direct me to relevant resource for further research.


Thanks in advance!


TG