OpenCV（七）—— 用滑动条做调色板

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• 创建滑动条 cv2.createTrackbar()
• 获取滑动条的值 cv2.getTrackbarPos()

import numpy as np
import cv2

def nothing():
    pass
#新建一个空白图像
img = np.zeros((300,512,3),np.uint8)
cv2.namedWindow('image')

#新建四个滑动条
cv2.createTrackbar('R','image',0,255,nothing)
cv2.createTrackbar('G','image',0,255,nothing)
cv2.createTrackbar('B','image',0,255,nothing)

switch = '0:OFF\n:ON'
cv2.createTrackbar(switch,'image',0,1,nothing)

while(1):
    cv2.imshow('image',img)
    k = cv2.waitKey(1)&0xFF
    if k == 27:
        break

    #获取滑动条的当前值
    r = cv2.getTrackbarPos('R','image')
    g = cv2.getTrackbarPos('G','image')
    b = cv2.getTrackbarPos('B','image')
    s = cv2.getTrackbarPos(switch,'image')

    if s == 0:
        img[:]=0
    else:
        img[:]=[b,g,r]

cv2.destroyAllWindows()

• 运行结果