[Python] Get math formula under the shape of PNG image to add LateX equation to your stackoverflow post

math_formula_img.py

#!/usr/bin/env python3

"""Insert LaTex equation (for https://stackoverflow.com/)

Add LaTex equation under the shape of PNG image to your stackoverflow post.
Print text to add to your post, and download the image equation if necessary.
(use https://chart.googleapis.com).

See help with -h and --help option for more details.

if MathJax, KaTeX or other javaScript display engine for mathematics
is used on the website, this script is outdated.

References:
- https://www.mathjax.org/
- https://khan.github.io/KaTeX/
- https://chart.googleapis.com (LateX section)
"""

# Authors: Gilles LEGOUX <gilles.legoux@gmail.com>
#
# MIT License
# Copyright (c) 2017  Gilles LEGOUX

if __name__ == '__main__':

    import sys

    if sys.version_info < (3, 2):
        sys.stderr.write("Sorry, requires Python 3.2+.\n")
        sys.stderr.write("See -h or --help options.\n")
        sys.exit(1)

    import os
    from argparse import ArgumentParser, RawDescriptionHelpFormatter
    from subprocess import call
    from urllib.parse import quote
    import uuid

    URL = 'https://chart.googleapis.com/chart?cht=tx&chl='

    parser = ArgumentParser(formatter_class=RawDescriptionHelpFormatter,
                            description=__doc__
                            )

    parser.add_argument("-e", "--editor",
                        dest="editor",
                        default="nano",
                        help="choose editor to write equation "
                             "(default nano)."
                        )

    parser.add_argument('-i', '--input',
                        dest="file",
                        default="equation.txt",
                        help="your math formula file "
                             "(default equation.txt)."
                        )

    parser.add_argument("-p", "--prefix",
                        dest="prefix",
                        default="stackoverflow_",
                        help="choose prefix for image name if download "
                             "(default stackoverflow_)."
                        )

    parser.add_argument("-d", "--dest",
                        dest="dest",
                        default="./",
                        help="choose where image will be downloaded "
                             "(default ./)."
                        )

    parser.add_argument("-n", "--no-download",
                        dest="download",
                        action="store_false",
                        help="choose if image will be download, "
                             "-p and -d options become useless if used "
                             "(by default download image)."
                        )

    args = parser.parse_args()

    _file = args.file
    editor = args.editor
    download = args.download
    dest = args.dest
    prefix = args.prefix

    call([editor, _file])

    with open(_file, 'r') as descriptor:
        # without end line file
        equation = descriptor.read()[:-1]

    encoded_equation = quote(equation)
    _uuid = uuid.uuid1()

    print('![{}]({}{})'.format(equation, URL, encoded_equation))
    if download:
        call(['wget',
              '{}{}'.format(URL, encoded_equation),
              '-O', '{}{}.png'.format(os.path.join(dest, prefix), _uuid),
              '-q'])