import cv2
import numpy as np


def nothing(x):
    pass

newim = cv2.imread("C:/Users/Slayer/Desktop/znak1.png")
table = []
cv2.namedWindow('swift')
part = newim


def handleclick(event, x, y, flags, param):
    global part, table
    if event == cv2.EVENT_LBUTTONDOWN:
        print(x,y)
        table.append((x, y))
        if len(table) >= 2:

            px1, py1 = table[0]
            px2, py2 = table[1]

            part = cv2.bitwise_not(newim[py1:py2, px1:px2])
            newim[py1:py2, px1:px2] = part
            table = []


cv2.setMouseCallback('swift', handleclick)

while True:
    cv2.imshow('swift', newim)
    k = cv2.waitKey(1) & 0xFF
    if k == ord('q'):
        break