monika.chr code decoder and encoder | Doki Doki Literature Club

monika_decode.py

#!/usr/bin/python
import getopt
import sys
from PIL import Image

def usage():
  print('Usage: monika_decode.py [-v] [FILE]')
  sys.exit(2)

def main(argv):
  if len(argv) == 0:
    usage()
  verbose = False
  input = ''
  for arg in argv:
    if arg == '-v':
      verbose = True
    else:
      input = arg
  if len(input) == 0:
    usage()
  image = Image.open(input)
  width, height = image.size
  
  i = 0
  value = 0
  bits = ''
  text = ''
  for y in range(height):
    for x in range(width):
      pixel = image.getpixel((x, y))
      mean = (pixel[0] + pixel[1] + pixel[2]) / 3
      bit = 1 if mean >= 128 else 0
      bits += str(bit)
      value = value | (bit << (7 - i))
      i += 1
      if i >= 8:
        text += chr(value)
        value = 0
        i = 0
    bits += '\n'
  if verbose:
    print('Input image: {}x{}'.format(width, height))
    print('Bits:')
    print(bits)
    print('Result string:')
  print(text)

if __name__ == '__main__':
  main(sys.argv[1:])

monika_encode.py

#!/usr/bin/python
import getopt
import sys
from math import ceil, sqrt
from PIL import Image

def main(argv):
  if len(argv) != 2:
    print('Usage: python monika_encode.py [INPUT_FILE] [OUTPUT_FILE]')
    sys.exit(2)
  
  with open(argv[0], 'r') as f:
    input = f.read()
  
  bits_count = len(input) * 8
  size = int(ceil(sqrt(bits_count)))
  image = Image.new("RGB", (size, size), "black")
  pixels = image.load()
  
  x = 0
  y = 0
  white = (255, 255, 255)
  for ch in input:
    value = ord(ch)
    for i in range(8):
      bit = (value >> (7-i)) & 1
      if bit == 1:
        pixels[x, y] = white
      x += 1
      if x >= size:
        x = 0
        y += 1
  image.save(argv[1], 'png')

if __name__ == '__main__':
  main(sys.argv[1:])