img2blocks - bitmap to Unicode sextants

img2blocks.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import sys
from PIL import Image
import PIL.ImageOps
import numpy as np

# give usage and exit if no arguments
if len(sys.argv) == 1:
    print("Usage:", sys.argv[0], "image")
    exit(1)

# encodes all 64 states in a lookup string
# " 🬞🬏🬭🬇🬦🬖🬵🬃🬢🬓🬱🬋🬩🬚🬹🬁🬠🬑🬯🬉▐🬘🬷🬅🬤🬔🬳🬍🬫🬜🬻🬀🬟🬐🬮🬈🬧🬗🬶🬄🬣▌🬲🬌🬪🬛🬺🬂🬡🬒🬰🬊🬨🬙🬸🬆🬥🬕🬴🬎🬬🬝█"

lookup = (
    "\N{NO-BREAK SPACE}"
    "\N{BLOCK SEXTANT-6}"
    "\N{BLOCK SEXTANT-5}"
    "\N{BLOCK SEXTANT-56}"
    "\N{BLOCK SEXTANT-4}"
    "\N{BLOCK SEXTANT-46}"
    "\N{BLOCK SEXTANT-45}"
    "\N{BLOCK SEXTANT-456}"
    "\N{BLOCK SEXTANT-3}"
    "\N{BLOCK SEXTANT-36}"
    "\N{BLOCK SEXTANT-35}"
    "\N{BLOCK SEXTANT-356}"
    "\N{BLOCK SEXTANT-34}"
    "\N{BLOCK SEXTANT-346}"
    "\N{BLOCK SEXTANT-345}"
    "\N{BLOCK SEXTANT-3456}"
    "\N{BLOCK SEXTANT-2}"
    "\N{BLOCK SEXTANT-26}"
    "\N{BLOCK SEXTANT-25}"
    "\N{BLOCK SEXTANT-256}"
    "\N{BLOCK SEXTANT-24}"
    "\N{RIGHT HALF BLOCK}"
    "\N{BLOCK SEXTANT-245}"
    "\N{BLOCK SEXTANT-2456}"
    "\N{BLOCK SEXTANT-23}"
    "\N{BLOCK SEXTANT-236}"
    "\N{BLOCK SEXTANT-235}"
    "\N{BLOCK SEXTANT-2356}"
    "\N{BLOCK SEXTANT-234}"
    "\N{BLOCK SEXTANT-2346}"
    "\N{BLOCK SEXTANT-2345}"
    "\N{BLOCK SEXTANT-23456}"
    "\N{BLOCK SEXTANT-1}"
    "\N{BLOCK SEXTANT-16}"
    "\N{BLOCK SEXTANT-15}"
    "\N{BLOCK SEXTANT-156}"
    "\N{BLOCK SEXTANT-14}"
    "\N{BLOCK SEXTANT-146}"
    "\N{BLOCK SEXTANT-145}"
    "\N{BLOCK SEXTANT-1456}"
    "\N{BLOCK SEXTANT-13}"
    "\N{BLOCK SEXTANT-136}"  # moved up past LEFT HALF BLOCK
    "\N{LEFT HALF BLOCK}"
    "\N{BLOCK SEXTANT-1356}"
    "\N{BLOCK SEXTANT-134}"
    "\N{BLOCK SEXTANT-1346}"
    "\N{BLOCK SEXTANT-1345}"
    "\N{BLOCK SEXTANT-13456}"
    "\N{BLOCK SEXTANT-12}"
    "\N{BLOCK SEXTANT-126}"
    "\N{BLOCK SEXTANT-125}"
    "\N{BLOCK SEXTANT-1256}"
    "\N{BLOCK SEXTANT-124}"
    "\N{BLOCK SEXTANT-1246}"
    "\N{BLOCK SEXTANT-1245}"
    "\N{BLOCK SEXTANT-12456}"
    "\N{BLOCK SEXTANT-123}"
    "\N{BLOCK SEXTANT-1236}"
    "\N{BLOCK SEXTANT-1235}"
    "\N{BLOCK SEXTANT-12356}"
    "\N{BLOCK SEXTANT-1234}"
    "\N{BLOCK SEXTANT-12346}"
    "\N{BLOCK SEXTANT-12345}"
    "\N{FULL BLOCK}"
)

im = Image.open(sys.argv[1])
# if image is not 1-bit, convert it
if im.mode != "1":
    im = im.convert("1")

# if image width is not a multiple of 2 pixels, fix that
if im.size[0] % 2:
    im2 = Image.new("1", (im.size[0] + 1, im.size[1]), "white")
    im2.paste(im, (0, 0))
    im = im2
    del im2

# if image height is not a multiple of 3 pixels, fix that
if im.size[1] % 3:
    im2 = Image.new(
        "1", (im.size[0], im.size[1] + 3 - im.size[1] % 3), "white"
    )
    im2.paste(im, (0, 0))
    im = im2
    del im2


# Invert image, via greyscale for compatibility
#  (no, I don't know why I need to do this)
im = PIL.ImageOps.invert(im.convert('L'))
# ... and now convert back to single bit
im = im.convert('1')
    
for y in range(0, im.size[1], 3):
    output = ""
    for x in range(0, im.size[0], 2):
        data = np.array(im.crop((x, y, x + 2, y + 3)))
        output += lookup[(np.packbits(data)[0] // 4) & 63]
    print(output)