OpenCV-Python Trackbar

参考

• Trackbar as the Color Palette

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代码

import cv2
import numpy as np


def nothing(x):
    pass


# Create a black image, a window
img = np.zeros((300, 512, 3), np.uint8)
cv2.namedWindow('image')

# create trackbars for color change
cv2.createTrackbar('R', 'image', 0, 255, nothing)
cv2.createTrackbar('G', 'image', 0, 255, nothing)
cv2.createTrackbar('B', 'image', 0, 255, nothing)

# create switch for ON/OFF functionality
switch = '0 : OFF \n 1 : ON'
cv2.createTrackbar(switch, 'image', 0, 1, nothing)

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

    # get current positions of four trackbars
    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()

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效果