textimg.py

#!/usr/bin/env python3
"""
Make an image with some text. Example:

    ./textimg.py -f fonts/SourceCodePro-Regular.otf 'Hello, world.'

"""
import argparse
import subprocess
import sys


DEFAULT_FILENAME = 'image.png'
DEFAULT_WIDTH = 900
DEFAULT_HEIGHT = 0
DEFAULT_FONT = 'Arial'
DEFAULT_FONTSIZE = 72
DEFAULT_FGCOLOR = '#4C4C4C'
DEFAULT_BGCOLOR = 'white'


def write_image(text, filename, attrs):
    """
    Generate an image with text in the center.
    """
    width = getattr(attrs, 'width', DEFAULT_WIDTH)
    height = getattr(attrs, 'height', DEFAULT_HEIGHT)
    font = getattr(attrs, 'font', DEFAULT_FONT)
    fontsize = getattr(attrs, 'font_size', DEFAULT_FONTSIZE)
    fgcolor = getattr(attrs, 'fg_color', DEFAULT_FGCOLOR)
    bgcolor = getattr(attrs, 'bg_color', DEFAULT_BGCOLOR)

    size = '{}x{}'.format(width, height or width)

    process = subprocess.run([
        'convert',
        '-background', bgcolor,
        '-fill', fgcolor,
        '-size', size,
        '-font', font,
        '-pointsize', str(fontsize),
        '-gravity', 'center',
        'label:' + text,
        filename,
    ])
    process.check_returncode()


def main():
    """
    Main entry point.
    """
    parser = argparse.ArgumentParser()
    parser.add_argument('text', metavar='TEXT')
    parser.add_argument('-o', '--output', metavar='FILENAME',
                        dest='filename', default=DEFAULT_FILENAME)
    parser.add_argument('-w', '--width', metavar='PIXELS',
                        type=int, default=DEFAULT_WIDTH)
    parser.add_argument('-H', '--height', metavar='PIXELS',
                        type=int, default=DEFAULT_HEIGHT)
    parser.add_argument('-f', '--font', metavar='FONT',
                        default=DEFAULT_FONT)
    parser.add_argument('-s', '--font-size', metavar='POINTS',
                        default=DEFAULT_FONTSIZE)
    parser.add_argument('-c', '--fg-color', metavar='COLOR',
                        default=DEFAULT_FGCOLOR)
    parser.add_argument('-b', '--bg-color', metavar='COLOR',
                        default=DEFAULT_BGCOLOR)

    if not sys.argv[1:]:
        parser.print_help()
        return

    args = parser.parse_args()

    try:
        write_image(args.text, args.filename, args)
    except subprocess.CalledProcessError as err:
        parser.error(err)

if __name__ == '__main__':
    sys.exit(main())