【OpenCV】4 TrackBar控件

import cv2
import numpy as np

# 回调函数：什么都不做
def callback():
    pass

# 创建窗口
cv2.namedWindow('trackbar', cv2.WINDOW_NORMAL)

# 创建TrackBar
cv2.createTrackbar('R', 'trackbar', 0, 255, callback)
cv2.createTrackbar('G', 'trackbar', 0, 255, callback)
cv2.createTrackbar('B', 'trackbar', 0, 255, callback)

# 纯黑色背景
img = np.zeros((480, 640, 3), np.uint8)

while True:
    cv2.imshow('trackbar', img)
    r = cv2.getTrackbarPos('R', 'trackbar')
    g = cv2.getTrackbarPos('G', 'trackbar')
    b = cv2.getTrackbarPos('B', 'trackbar')

    # 改变背景色
    img[:] = [b, g, r]

    key = cv2.waitKey(10)
    if (key & 0xFF == ord('q')):
        break

cv2.destroyAllWindows()