Trackbar.py

# -*- coding: utf-8 -*-
"""
Created on Sun Jan 5 13:51:34 2014
@author: duan
"""
import cv2
import numpy as np

def nothing(x):
    pass

# 创建一副黑色图像
img=np.zeros((300,512,3),np.uint8)
cv2.namedWindow('image')
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,'image')

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

cv2.destroyAllWindows()