File:Amiga HAM8 demo image.png

# Convert a PNG file to 24-bit IFF-ILBM

import pygame

img = pygame.image.load("320px.png")

# image width and height
W, H = img.get_size()

def bit16(i):
    return [i // 256, i % 256]

w1, w2 = bit16(W)
h1, h2 = bit16(H)

def bit32(i):
    h = "%08x" % i
    w = [h[k:k+2] for k in (0,2,4,6)]
    return [int(q, 16) for q in w]

form = [
 70,   # F
 79,   # O
 82,   # R
 77,   # M
]

ilbm = [
 73,   # I
 76,   # L
 66,   # B
 77,   # M
 66,   # B
 77,   # M
 72,   # H
 68,   # D
  0,   #   s
  0,   #   i
  0,   #   z
 20,   #   e
 w1,   # wid 1
 w2,   # wid 2
 h1,   # hei 1
 h2,   # hei 2
  0,   #  xor 1
  0,   #  xor 2
  0,   #  yor 1
  0,   #  yor 2
 24,   # planes
  0,   # mask 
  0,   # compression
  0,   # pad
  0,   #  trans1
  0,   #  trans2
 10,   # x aspect
 11,   # y aspect
 w1,   #  x wid1
 w2,   #  x wid2
 h1,   #  y hei1
 h2,   #  y hei2
 66,   # B
 79,   # O
 68,   # D
 89,   # Y
]


p = []


def bit_at(x, y, col, b):
    c = img.get_at((x, y))[col]
    c = ( c >> b ) & 1
    return c

for y in range(H):
    for col in 0, 1, 2:
        for b in range(8):
            line = []
            for x in range(W):
                line.append(bit_at(x, y, col, b))
            for n in range(0, W, 8):
                bb = "".join([str(q) for q in line[n:n+8]])
                p.append(int(bb, 2))

out = ilbm + bit32(len(p)) + p

out = form + bit32(len(out)) + out

out = bytearray(out)

g = open("i24.iff", "wb")

g.write(out)

g.close()