generate_fontstyle

#!/usr/bin/env python3

import argparse
import sys
from os import path

try:
    import fontforge
except ImportError:
    sys.exit(
        "FontForge module could not be loaded. Try installing fontforge python bindings "
        "[e.g. on Linux Debian or Ubuntu: `sudo apt install fontforge python-fontforge`]"
    )


def generate_style(font: fontforge.font, style: str, opts):
    font.fontname += style
    font.selection.all()
    for glyph in font.selection.byGlyphs:
        if "Bold" in style:
            glyph.changeWeight(opts.embolden)
        if 'Italic' in style:
            glyph.italicize(opts.angle)


if __name__ == "__main__":
    parser = argparse.ArgumentParser(
        description="Generate Bold/Italic versions for specified font file",
    )

    parser.add_argument('font', help='The path to the font')
    parser.add_argument(
        '-b', '--bold',
        dest="styles",
        action="append_const",
        const="Bold",
        help="generate bold version")
    parser.add_argument(
        '-i', '--italic',
        dest="styles",
        action="append_const",
        const="Italic",
        help="generate italic version")
    parser.add_argument(
        '-bi', '--bolditalic',
        dest="styles",
        action="append_const",
        const="BoldItalic",
        help="generate bold and italic version")
    parser.add_argument(
        '-em', '--embolden-em',
        dest="embolden",
        type=int,
        default=5,
        help="set embolden scale (by em unit)")
    parser.add_argument(
        '-ag', '--italic-angle',
        dest="angle",
        type=int,
        default=-13,
        help="set italic angle")
    parser.add_argument(
        '-o', '--out-dir',
        dest="outdir",
        default=".",
        help="set italic angle")

    args = parser.parse_args()

    if not args.styles:
        args.styles = ['Bold', 'Italic', 'BoldItalic']

    font = fontforge.open(args.font)
    for style in args.styles:
        generate_style(font, style, args)
        dotindex = args.font.rindex('.')
        name = args.font[:dotindex]
        ext = args.font[dotindex:]
        font.generate(path.join(args.outdir, name + style + ext))