qr.oqwo.org - qr code generator

usage:
  https://qr.oqwo.org/?data=hello          styled svg, black on white
  https://qr.oqwo.org/?data=hello&f=png    png, transparent background

params:
  data     text to encode (required, url-encode it)
  f        output: svg (default) | svgt (svg, no background) | png
  ecc      error correction: l | m (default) | q | h
  margin   quiet zone in modules, 0-16 (default 4)
  scale    px per module, 2-64 (default 12)
  fg       module colour, hex (default 000)
  bg       background colour, hex (default fff for svg, none for svgt/png)

keep fg dark on a light bg or scanners will struggle

header api:
  same params as request headers on /api/gen:
  curl https://qr.oqwo.org/api/gen -H "data: hello" -H "f: png" -o qr.png