Fontforge script to generate a vertical font : all glyphs are rotated 90 degrees anticlockwise

generate_vertical_font.py

#!/usr/bin/env python
#
# Usage:
# fontforge -script generate_vertical_font.py original_font.ttf

import fontforge
import math
import os
import psMat
import sys
import logging
from glob import glob


logger = logging.getLogger()
logger.setLevel(logging.DEBUG)
console_logger = logging.StreamHandler()
console_logger.setLevel(logging.DEBUG)
logger.addHandler(console_logger)


def create_vertical_font(font_path: str):

    if "Vert-" in font_path:
        info_string = f"{font_path} may be converted already, skip."
        logger.info(info_string)
        return

    ff = fontforge.open(font_path)

    if ff.is_cid:
        info_string = f"{font_path} is CID font, skip."
        logger.error(info_string)
        return

    info_string = f"Convert starting: {font_path}"
    logger.info(info_string)

    new_sfnt_names = tuple(
        (
            i[0],
            i[1],
            "Vert " + i[2]
            if i[1]
            in ("Family", "Fullname", "Preferred Family", "Trademark", "UniqueID")
            else i[2],
        )
        for i in ff.sfnt_names
    )
    ff.sfnt_names = new_sfnt_names
    ff.fontname = "Vert-" + ff.fontname
    ff.familyname = "Vert " + ff.familyname
    ff.fullname = "Vert " + ff.fullname

    vertical_lookups = [
        x
        for x in ff.gsub_lookups
        if x.startswith("'vert'")
        or x.startswith("'vrt2'")
        or x in ("gsubvert", "j-vert")
    ]
    vertical_lookup_subtables = sum(
        [ff.getLookupSubtables(x) for x in vertical_lookups], ()
    )

    matrix = psMat.compose(
        psMat.rotate(math.radians(90)),
        psMat.translate(ff.em - ff.descent, -ff.descent),
    )

    for glyph in ff.glyphs():
        if glyph.width == ff.em:
            for subtable in vertical_lookup_subtables:
                tables = glyph.getPosSub(subtable)
                if len(tables):
                    ff.selection.select(tables[0][2])
                    ff.copy()
                    ff.selection.select(glyph.glyphname)
                    ff.paste()
                    break
            glyph.transform(matrix)

    converted_font_path = (
        "Vert-" + os.path.splitext(os.path.basename(font_path))[0] + ".ttf"
    )
    info_string = f"Writing font to {converted_font_path}"
    logger.info(info_string)
    ff.generate(converted_font_path)


if __name__ == "__main__":
    fonts_path = [font for arg in sys.argv[1:] for font in glob(arg)]
    for font in fonts_path:
        create_vertical_font(font)