Python OpenCV - destroyAllWindows() Function

Python Opencv destroyAllWindows() function allows users to destroy or close all windows at any time after exiting the script. If you have multiple windows open at the same time and you want to close then you would use this function. It doesn't take any parameters and doesn't return anything. It is similar to destroyWindow() function but this function only destroys a specific window unlike destroyAllWindows().

Example 1: Closing window using  destroyWindow() function

In the Python script given below, we have created two windows named 'P' and 'Q' respectively that displayed an image of "gfg_logo.png" using the cv2.imshow() function that is supposed to display window 'P' first on the screen but before calling the waitKey() function to delay the closing of windows, we will destroy only the window named 'P' with destroyWindow('P') function by passing the window name 'P' as its argument. We will see that the window 'Q' is only displayed on the screen which will close only when the user closes it.

# importing cv2 module
import cv2

# read the image
img = cv2.imread("gfg_logo.png")

# showing the images
cv2.imshow('P', img)
cv2.imshow('Q', img)

# Destroying the window named P before
# calling the waitKey() function
cv2.destroyWindow('P')

# using the wait key function to delay the
# closing of windows till any key is pressed
cv2.waitKey(0)

Output:

Example 2:  Closing window using destroyAllWindows() function

In this case, instead of calling destroyWindow() to delete or close a particular window, we will use destroyAllWindows() to destroy all windows on the screen here we have called this function before waitKey(0), so the images will not at all displayed on the screen. DestroyAllWindows() is just a good coding practice. 

# importing cv2 module
import cv2

# read the image
img = cv2.imread("gfg_logo.png")

# showing the images
cv2.imshow('P', img)
cv2.imshow('Q', img)

# Destroying All the windows
cv2.destroyAllWindows()

# using the wait key function to delay
# the closing of windows till any key is pressed
cv2.waitKey(0)

Output: