Convert Image to Braille Unicode text (using PIL)

braille.py

'''Convert image to braille text'''
import argparse

from PIL import Image


def parse_args():
    parser = argparse.ArgumentParser()
    parser.add_argument("-t", "--th", default=127, type=int, dest="threadh")
    parser.add_argument("-w", "--width", default=120, type=int, dest="width")
    parser.add_argument("-s", "--scale", default=1.0, type=float, dest="scale")
    parser.add_argument(
        "-i", "--invert", action="store_true", dest="invert"
    )
    parser.add_argument('file' )
    return parser.parse_args()


def convert(imgfile: str, width=160, scale=1.0, cutoff=127, invert=False) -> str:
    res: list[str] = []

    # load image
    im_src = Image.open(imgfile)
    WIDTH = int(width * scale)
    HEIGHT = int(WIDTH / im_src.width * im_src.height)

    # create black/white image
    im_res: Image.Image = (
        im_src.convert("L")
        .resize((WIDTH, HEIGHT), resample=Image.HAMMING)
        .point(lambda x: x > cutoff if invert else x < cutoff, mode="1")
    )

    # check every pixel (row step: 4, col step: 2)
    for row in range(0, im_res.height, 4):
        line: list[str] = []
        for col in range(0, im_res.width, 2):
            val, i = 0, 0
            for c_pos in range(0, 2):
                for r_pos in range(0, 4):
                    if col + c_pos < im_res.width and row + r_pos < im_res.height:
                        p = im_res.getpixel((col + c_pos, row + r_pos))
                    else:
                        p = 0
                    if p > 0:
                        val += 1 << i
                    i += 1
            line.append(chr(0x2800 + val))
        res.append("".join(line))
    return "\n".join(res)


if __name__ == '__main__':
    args = parse_args()
    print(convert(args.file, args.width, args.scale, args.threadh, args.invert))