qr code from url

qr.py

#!/usr/bin/env python3
"""Generate a QR code from a URL

usage: qr.py [-h] [--url URL] [--interactive] [--output OUTPUT] [--size SIZE]

options:
  -h, --help       show this help message and exit
  --url URL
  --interactive
  --output OUTPUT  a PNG file
  --size SIZE

"""

import sys
import argparse
import qrcode

import matplotlib as mpl
import matplotlib.pyplot as plt

# Parse command line arguments
parser = argparse.ArgumentParser()
parser.add_argument('--url')
parser.add_argument("--interactive", action = "store_true")
parser.add_argument("--output", default = None, help = "a PNG file")
parser.add_argument('--size', default=10, type=int)
ns = parser.parse_args()

# Create the QR image
img = qrcode.make(ns.url)

if ns.interactive:
  # Create a matplotlib figure and display the image
  mpl.interactive(True)
  fig = plt.figure('qr', figsize=(ns.size,ns.size))
  ax  = fig.gca()
  ax.imshow(img, cmap='gray', vmin=0, vmax = 1)
  ax.xaxis.set_ticks([])
  ax.yaxis.set_ticks([])

  # Add a key-press exit handler to the figure
  fig.canvas.callbacks.connect('key_press_event', lambda event: sys.exit(0))

  input("press <enter> to exit")

else:
  if ns.output is None:
    parser.error("either --interactive or --output must be specified")
  img.save(ns.output, "PNG")