steganography.py 文件源码

def insert_text(img, dest, msg):
    image = Image.open(img)
    width, height = image.size

    if image.mode[:3] != "RGB" or width * height * 3 < len(msg) + RESERVED_PIXELS * 3:
        raise IndexError("Unable to use this picture")

    bits = bin(len(msg))[2:].zfill(RESERVED_PIXELS * 3)
    msg = bits + msg

    msg = enumerate(msg + "0" * (3 - len(msg) % 3))
    p = image.load()

    for i, j in pixels(image.size):
        try:
            rgb = map(lambda color, bit: color - (color % 2) + int(bit), p[i, j][:3], [msg.next()[1] for _ in xrange(3)])
            p[i, j] = tuple(rgb)
        except StopIteration:
            image.save(dest, "PNG", quality = 100)
            return