emoji_resize.py

#!/usr/bin/env python

"""
Pre-processing of emoji images.
Requires ImageMagick (mogrify) to be installed and available via CLI.
"""

import argparse
import os
import subprocess

def parse_args():
    parser = argparse.ArgumentParser(
        description='Preprocessing of emoji assets for use in the app.')
    parser.add_argument(
        'source', help='the source image directory')
    parser.add_argument(
        'output', help='the output path to write the resultant images')
    return parser.parse_args()

def main():
    args = parse_args()
    output = args.output
    source = args.source

    # Prepare the output directory.
    if not os.path.exists(output):
        os.makedirs(output)

    # Build the command.
    command = [
        'mogrify',
        '-path',
        output,

        # Add some padding.
        '-bordercolor',
        'transparent',
        '-border',
        '1x1',

        # Resize.
        '-resize',
        '32x32',

        os.path.join(source, '*.png'),
    ]

    subprocess.call(command)

if __name__ == "__main__":
    main()