OpenCV(三)：如何用OpenCV创建颜色滑动条_cv2 在视频添加彩色条

	import cv2
	import numpy as np
	
	def nothing(x):
	    pass
	
	#创建一幅黑色图像
	img = np.zeros((400,512,3),np.uint8)
	cv2.namedWindow('image')
	
	#'R'为滑动条的名字,'image'为滑动条被放置窗口的名字,0：滑动条的默认位置，255：滑动条的最大位置，nothing是回调函数
	cv2.createTrackbar('R','image',0,255,nothing)
	cv2.createTrackbar('G','image',0,255,nothing)
	cv2.createTrackbar('B','image',0,255,nothing)
	
	switch='0:OFF\n1:ON'
	cv2.createTrackbar(switch,'image',0,1,nothing)
	
	while(1):
	    cv2.imshow('image',img)
	    k = cv2.waitKey(1)& 0xFF
	    if k==27:
	        break
	
	    r = cv2.getTrackbarPos('R','image')
	    g = cv2.getTrackbarPos('G','image')
	    b = cv2.getTrackbarPos('B','image')
	    s = cv2.getTrackbarPos(switch,'
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