ImageMessage.py

import sys
from PIL import Image


def encode(image, msg):
    im = Image.open(image)
    pix = im.load()
    width, height = im.size
    ms = list(open(msg, "r+").read())

    for i in range(0, height):
        for j in range(0, width):
            if (i * width) + j > len(ms) - 1:
                break
            c = ord(ms[(i * width) + j])

            p3 = pix[j, i][2] - (pix[j, i][2] % 10) + (c % 10)
            if p3 > 255:
                p3 -= 10
            c = int(c / 10)
            p2 = pix[j, i][1] - (pix[j, i][1] % 10) + (c % 10)
            if p2 > 255:
                p2 -= 10
            c = int(c / 10)
            p1 = pix[j, i][0] - (pix[j, i][0] % 10) + c
            if p1 > 255:
                p1 -= 10

            pix[j, i] = (p1, p2, p3)

        if (i * width) + j > len(ms) - 1:
            p3 = pix[j, i][2] - (pix[j, i][2] % 10)
            p2 = pix[j, i][1] - (pix[j, i][1] % 10)
            p1 = pix[j, i][0] - (pix[j, i][0] % 10)
            pix[j, i] = (p1, p2, p3)
            break

    im.save("./out.png", format="PNG", compress_level=0)


def decode(image, out):
    im = Image.open(image)
    pix = im.load()
    width, height = im.size
    msg = ""
    breakFlag = False

    for i in range(0, height):
        for j in range(0, width):
            p3 = pix[j, i][2] % 10
            p2 = pix[j, i][1] % 10
            p1 = pix[j, i][0] % 10
            val = p1 * 100 + p2 * 10 + p3

            if val == 0:
                breakFlag = True
                break
            try:
                c = chr(val)
            except ValueError:
                c = ""
            msg += c
        if breakFlag:
            break

    with open(out, "w") as f:
        f.write(msg)


def main():
    try:
        flag = sys.argv[1]
        image = sys.argv[2]
        file = sys.argv[3]
    except IndexError:
        print("Invalid args. Correct usage:")
        print("  ImageMessage -[e,d] <imagename> <in/output filename>")
        return -1

    if flag == "-e":
        try:
            encode(image, file)
        except AttributeError:
            print("Invalid image name")
    elif flag == "-d":
        try:
            decode(image, file)
        except AttributeError:
            print("Invalid image name")
    else:
        print("Invalid args. Correct usage:")
        print("  ImageMessage -[e,d] <imagename> <in/output filename>")


if __name__ == "__main__":
    main()