John's Blog

#!/usr/bin/env python
 
import sys, Image
 
REDUCE_MARKS = [16, 32, 48, 64, 80, 96, 112, 128, 144, 160, 176, 192, 208, 224, 240]
 
def reduce_color(c):
    val = 0
    for mark in REDUCE_MARKS:
        if c > mark:
            val += 1
        else:
            break
    return val
 
def main():
    if len(sys.argv) != 3:
        raise Exception('Must have 2 arguments. %s input.image output.epub.thn' % sys.argv[0])
 
    outf = open(sys.argv[2], 'wb')
 
    im = Image.open(sys.argv[1]).convert("L")
    im.thumbnail((96, 144))
 
    newim = Image.new('L', (96, 144), 'white')
 
    x,y = im.size
    newim.paste(im, ((96-x)/2, (144-y)/2))
 
    outf.write('t4bp')
 
    px = []
    for p in newim.getdata():
        px.append(p)
        if len(px) == 2:
            byte_val = bin(reduce_color(px[0]))[2:].zfill(4) + bin(reduce_color(px[1]))[2:].zfill(4)
            outf.write(chr(int(byte_val, 2)))
            px = []
        elif len(px) > 2:
            raise Exception('Fatal error px length increased past 2.')
 
    outf.close()
 
if __name__ == '__main__':
    main()

#!/usr/bin/env python
 
import sys, os
 
def get_greys(b):
    if not b:
        return 0, 0
 
    b = bin(int(ord(b)))
    b = b[2:].zfill(8)
 
    w = str(int(b[0:4], 2))
    x = str(int(b[4:8], 2))
 
    return w, x
 
def main():
    if len(sys.argv) != 3:
        raise Exception('Must have 2 arguments. %s input.epub.thm output.pgm' % sys.argv[0])
 
    t4bfile = open(sys.argv[1], 'rb')
    pgmfile = open(sys.argv[2], 'w')
 
    pgmfile.write('P2\n96 144\n15\n')
 
    # Read past the t4b header
    t4bfile.read(4)
 
    for i in range(144):
        for j in range(48):
            b = t4bfile.read(1)
 
            vals = get_greys(b)
            pgmfile.write('%s %s ' % (vals[0], vals[1]))
        pgmfile.write('\n')
 
    pgmfile.close()
    t4bfile.close()
 
if __name__ == '__main__':
    main()