mixing pixels of an image manually using python

Question

I am trying to create an algorithm that blends the pixels of an image and I can bring the image as it was before, but I do not know do this.

I'm using python and pil, but I can use other libraries.

Exemple: toand back to

Thank you.

Answer 1

This should do it. There's no error handling, it doesn't follow pep8 standards, it uses slow PIL operations and it doesn't use an argument parsing library. I'm sure there are other bad things about it also.

It works by seeding python's random number generator with an invariant of the image under scrambling. The hash of the size is used. Since the size doesn't changed, a random sequence built on it will be the same for all images that share the same size. That sequence is used as a one-to-one mapping, therefore it's reversible.

The script may be invoked twice from a shell to create two images, "scrambled.png" and "unscrambled.png". "Qfhe3.png" is the source image.

python scramble.py scramble "./Qfhe3.png"
python scramble.py unscramble "./scrambled.png"

#scramble.py
from PIL import Image
import sys
import os
import random

def openImage():
    return Image.open(sys.argv[2])

def operation():
    return sys.argv[1]

def seed(img):
    random.seed(hash(img.size))

def getPixels(img):
    w, h = img.size
    pxs = []
    for x in range(w):
        for y in range(h):
            pxs.append(img.getpixel((x, y)))
    return pxs

def scrambledIndex(pxs):
    idx = list(range(len(pxs)))
    random.shuffle(idx)
    return idx

def scramblePixels(img):
    seed(img)
    pxs = getPixels(img)
    idx = scrambledIndex(pxs)
    out = []
    for i in idx:
        out.append(pxs[i])
    return out

def unScramblePixels(img):
    seed(img)
    pxs = getPixels(img)
    idx = scrambledIndex(pxs)
    out = list(range(len(pxs)))
    cur = 0
    for i in idx:
        out[i] = pxs[cur]
        cur += 1
    return out

def storePixels(name, size, pxs):
    outImg = Image.new("RGB", size)
    w, h = size
    pxIter = iter(pxs)
    for x in range(w):
        for y in range(h):
            outImg.putpixel((x, y), next(pxIter))
    outImg.save(name)

def main():
    img = openImage()
    if operation() == "scramble":
        pxs = scramblePixels(img)
        storePixels("scrambled.png", img.size, pxs)
    elif operation() == "unscramble":
        pxs = unScramblePixels(img)
        storePixels("unscrambled.png", img.size, pxs)
    else:
        sys.exit("Unsupported operation: " + operation())

if __name__ == "__main__":
    main()