cv2.createTrackbar使用回调函数创建滑动色块

import cv2
import numpy as np

def nothing®:
g = cv2.getTrackbarPos(‘G’, ‘image’)
b = cv2.getTrackbarPos(‘B’, ‘image’)
img[:] = [b, g, r]
cv2.imshow(‘image’, img)

def nothing1(g):
r =cv2.getTrackbarPos(‘R’,‘image’)
b = cv2.getTrackbarPos(‘B’, ‘image’)
img[:] = [b, g, r]
cv2.imshow(‘image’, img)

def nothing2(b):
r=cv2.getTrackbarPos(‘R’,‘image’)
g = cv2.getTrackbarPos(‘G’, ‘image’)
img[:] = [b, g,r]
cv2.imshow(‘image’, img)

创建一个黑色背景图和一个窗口

img = np.zeros((300,512,3), np.uint8)
cv2.namedWindow(‘image’)

创建3个trackbar

cv2.createTrackbar(‘R’,‘image’,0,255,nothing)
cv2.createTrackbar(‘G’,‘image’,0,255,nothing1)
cv2.createTrackbar(‘B’,‘image’,0,255,nothing2)

cv2.imshow(‘image’,img)
k = cv2.waitKey(0)

cv2.destroyAllWindows()