Skip to content
Related Articles

Related Articles

Improve Article

Python | OpenCV BGR color palette with trackbars

  • Last Updated : 13 Nov, 2018

OpenCV is a library of programming functions mainly aimed at real-time computer vision.
In this article, Let’s create a window which will contain RGB color palette with track bars. By moving the trackbars the value of RGB Colors will change b/w 0 to 255. So using the same, we can find the color with its RGB values.

Libraries needed:

Create a black window with three color channels with resolution 512 x 512. Then create three ‘B’ ‘G’ ‘R’ trackbars using predefined functions of OpenCV library. Set the values of channels from 0 to 255. Merging the black window with these color trackbars.

# Python program to create RGB color  
# palette with trackbars 
# importing libraries
import cv2
import numpy as np
# empty function called when
# any trackbar moves
def emptyFunction():
def main():
    # blackwindow having 3 color chanels
    image = np.zeros((512, 512, 3), np.uint8) 
    windowName ="Open CV Color Palette"
    # window name
    # there trackbars which have the name
    # of trackbars min and max value 
    cv2.createTrackbar('Blue', windowName, 0, 255, emptyFunction)
    cv2.createTrackbar('Green', windowName, 0, 255, emptyFunction)
    cv2.createTrackbar('Red', windowName, 0, 255, emptyFunction)
    # Used to open the window
    # till press the ESC key
        cv2.imshow(windowName, image)
        if cv2.waitKey(1) == 27:
        # values of blue, green, red
        blue = cv2.getTrackbarPos('Blue', windowName)
        green = cv2.getTrackbarPos('Green', windowName)
        red = cv2.getTrackbarPos('Red', windowName)
        # merge all three color chanels and
        # make the image composites image from rgb   
        image[:] = [blue, green, red]
        print(blue, green, red)
# Calling main()         
if __name__=="__main__":


Note: Above programs will not run on online IDE.

 Attention geek! Strengthen your foundations with the Python Programming Foundation Course and learn the basics.  

To begin with, your interview preparations Enhance your Data Structures concepts with the Python DS Course. And to begin with your Machine Learning Journey, join the Machine Learning – Basic Level Course

My Personal Notes arrow_drop_up
Recommended Articles
Page :