bareqr - Bare headless QR code generator

bareqr was derived from python-qrcode. I removed all dependencies, console scripts, renderers, and made it headless.

bareqr is:

• stateless
• threadsafe
• PEP-8 compliant
• fully typed

Main features

There is just one feature: produce the matrix.

from bareqr import qrcode
from pprint import pprint

qr = qrcode("1234")

pprint(qr.rows)
>>>
[[1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1],
 [1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1],
 [1, 0, 1, 1, 1, 0, 1, 0, 0, 0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1],
 [1, 0, 1, 1, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1],
 ...
 [1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 0, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0]]

bareqr won't automatically split data to chunks of different types. You may split data manually:

qr = qrcode("1234", "HELLO", "world")

For each chunk bareqr will choose the correct data type: number, alphanumeric or bytes.

The automatic splitting is available as a separate utility:

from bareqr import optimal_chunks

chunks = optimal_chunks("1234HELLOworld", min_chunk=4)
qr = qrcode(*chunks)

qrcode has an internal global cache of precomputed blank QR codes. In bareqr this cache is external and opt-in:

cache = {}
qr1 = qrcode("1234", blanks_cache=cache)
qr2 = qrcode("5678", blanks_cache=cache)

Extra features

Ok, in fact bareqr is not completely headless. There are two utils to render QR as ascii or png. Treat them as handy extras.

from bareqr import qrcode, as_ascii, as_png
qr = qrcode("1234")

asc = as_ascii(qr, border=2, invert=True)
for row in asc:
    print(row)

png = as_png(qr, border=2, scale=4)
with open("qr.png", "wb") as f:
    f.write(png)

The png encoder is custom to avoid extra dependencies.