parse-bdf-font.py

#!/usr/bin/env python3
import argparse
import string

def parse(bdf):
    font = { "glyphs": {} }
    name = None
    glyph = None
    lines = list(reversed(bdf.splitlines()))
    while len(lines) > 0:
        line = lines.pop()
        c = line.split(" ")
        if len(c) == 0:
            continue

        if c[0] == "STARTCHAR":
            glyph = {}
            name = c[1]
        elif name is None:
            continue
        elif c[0] == "ENDCHAR":
            font["glyphs"][glyph["ascii"]] = glyph
            name = None
            glyph = None
        elif c[0] == "ENCODING":
            glyph["encoding"] = c[1]
            # Adobe Standard Encoding is (nearly) identical with ASCII.
            glyph["ascii"] = chr(int(c[1]))
        elif c[0] == "BBX":
            glyph["bbx"] = {
                "width": int(c[1]),
                "height": int(c[2]),
                "off0x": int(c[3]),
                "off0y": int(c[4]),
            }
        elif c[0] == "BITMAP":
            bitmap = bytes()
            for _ in range(0, glyph["bbx"]["height"]):
                bitmap += bytes([int(lines.pop(), 16)])

            glyph["bitmap"] = bitmap

    if glyph:
        font["glyphs"][glyph["ascii"]] = glyph

    return font

def preview(font, glyph):
    g = font["glyphs"][glyph]
    if not g:
        print(f"'{glyph}' not found in the font file")

    print(f"Glyph: {glyph}")
    print(f"Encoding: {g['encoding']}")
    for line in g["bitmap"]:
        for i in range(0, 8):
            bit = (line >> (7 - i)) & 1 == 1
            if bit:
                print("#", end="") # black square
            else:
                print("_", end="")
        print("")

def main():
    parser = argparse.ArgumentParser(description="The BDF font file converter.")
    parser.add_argument("--preview", metavar="ASCII")
    parser.add_argument("--convert", metavar="OUTFILE")
    parser.add_argument("bdf_file")
    args = parser.parse_args()

    font = parse(open(args.bdf_file).read())
    if args.preview:
        preview(font, args.preview)

    if args.convert:
        bin_font = convert(font)
        with open(args.convert, "wb") as f:
            f.write(bin_font)

if __name__ == "__main__":
    main()