victormelo / pyescpos Goto Github PK

A Python support for Epson© ESC/POS® compatible printers. Read more at Epson ESCPOS FAQ (PDF document).

This project is inspired on Manuel F. Martinez work for python-escpos implementation, among other projects, whose specific bits of work (available here on Github and many other open-source repositories) has helped so much.

The ESC/POS® is a standard that every manufacturer tend to modify to suit their (even already implemented) needs. Indeed, there is no standard but something awkward, an illusion of a standard. On the surface, one can say that it's pretty much the same, but when you look just a little bit more deeper, you quickly realize that they are almost completely different, even between models belonging to the same manufacturer.

This project aims to make viable the use, at the point-of-sale (POS), of different printers (the most common ones, at least) that are minimally based on ESC/POS® standard, without need to modify the client application code. To achieve this, it is necessary to draw a lowest common denominator between features and provide implementations that seek to meet this minimum. At this stage of the project, "minimum" is still a fuzzy word.

Current implementation was tested against following hardwares:

Serial communications support requires PySerial version 2.7 or later.

from escpos.serial import SerialSettings
from escpos.impl.epson import GenericESCPOS

# assumes RTS/CTS for 'ttyS5' and infers an instance of RTSCTSConnection
conn = SerialSettings.as_from('/dev/ttyS5:9600,8,1,N').get_connection()
printer = GenericESCPOS(conn)
printer.init()
printer.text('Hello World!')

USB support requires PyUSB.

# TODO: USB support example.

Bluetooth support requires PyBlueZ (not yet implemented).

from escpos.bluetooth import BluetoothConnection
from escpos.impl.epson import GenericESCPOS

printer = GenericESCPOS(BluetoothConnection('01:0a:02:0b:03:0c'))
printer.init()
printer.text('Hello World!')

There is a default set of parameters for printing barcodes. Each ESC/POS implementation will take care of the details and try their best to print your barcode as you asked.

from escpos import barcode
from escpos.serial import SerialSettings
from escpos.impl.epson import GenericESCPOS

conn = SerialSettings.as_from('COM1:9600:8:1:N').get_connection()
printer = GenericESCPOS(conn)
printer.init()
printer.code128('0123456789',
        barcode_height=96, # ~12mm (~1/2")
        barcode_width=barcode.BARCODE_DOUBLE_WIDTH,
        barcode_hri=barcode.BARCODE_HRI_BOTTOM)

printer.lf()

printer.ean13('4007817525074',
        barcode_height=120, # ~15mm (~9/16"),
        barcode_width=barcode.BARCODE_NORMAL_WIDTH,
        barcode_hri=barcode.BARCODE_HRI_TOP)

printer.cut()

The barcode data should be complete, that is, an EAN-13 barcode is formed from twelve digits plus check-digit. Most of the ESC/POS commands implementations requires only twelve digits and automaticaly calculate the check-digit. If you are dealing with, say, EAN-13 codes without the thirteenth-digit (the check-digit) just append zero (0) to the barcode class (or method) argument, so they can pass RE validation.

printer.ean13('4007817525074')  # is OK
printer.ean13('400781752507')   # raises ValueError
printer.ean13('4007817525070')  # is OK and prints 4007817525074 as expected

It is important that you read this disclaimer.

None of the vendors or manufacturers cited in this entire project agree or endorse any of the patterns or implementations used. its names are used only where it makes sense and/or to maintain context.