import cv2
import numpy as np
from matplotlib import pyplot as plt

def callback(dst):
    print(dst)

# Load two images
img1 = cv2.imread('bg1.jpg')
img2 = cv2.imread('bg2.jpg')

dst = cv2.addWeighted(img1,0.7,img2,0.3,0)

cv2.namedWindow('boss')


cv2.createTrackbar('O', 'boss', 0, 10, callback)

while(1):
    cv2.imshow('boss',dst)
    k = cv2.waitKey(1) & 0xFF
    if k == 27:
        break
    # get current positions of four trackbars
    r = cv2.getTrackbarPos('O','boss')
    print(r)
    dst = cv2.addWeighted(img1,1,img2,1-(r/10),0)