Destroywindow Does Not Close Window on MAC Using Python and Opencv

DestroyWindow does not close window on Mac using Python and OpenCV

There are a few peculiarities with the GUI in OpenCV. The destroyImage call fails to close a window (atleast under Linux, where the default backend was Gtk+ until 2.1.0) unless waitKey was called to pump the events. Adding a waitKey(1) call right after destroyWindow may work.

Even so, closing is not guaranteed; the the waitKey function is only intercepted if a window has focus, and so if the window didn't have focus at the time you invoked destroyWindow, chances are it'll stay visible till the next destroyWindow call.

I'm assuming this is a behaviour that stems from Gtk+; the function didn't give me any trouble when I used it under Windows.

Python Image Window Not Closing Properly on Mac

I believe the quit is acting as an interrupt, which quits the entire python program. This is different than pressing a key, which is incorporated into the logic of the actual program and continues to completion:

cv2.waitKey(0) # waits for any key to be pressed to continue the logic of the program
# this is what actually allows you to "display" an image without it immediately disappearing.

Python, OpenCV can't close last window

Try to add some cv2.waitKey after destroyAllWindows:

cv2.destroyAllWindows()
for i in range(5):    # maybe 5 or more
    cv2.waitKey(1)

Sometimes, it works.

How can I close a cv2 window?

I couldn't quite replicate your error (I ended up crashing Python with your code), but I did come up with a fix.

while ok_flag:
    (ok_flag, img) = cap.read()
    cv2.imshow("CallingCamera View", img)
    if cv2.waitKey(0) == 27:
        ok_flag = False

cv2.destroyAllWindows()

I wasn't sure if you had a reason for setting the waitKey time to 1ms or not, for testing purposes setting it to 0 (forever) worked just the same. I guess setting it to 1ms for you would get you the most recent image? My test was run with a static image residing on my desktop. Otherwise removing the two breaks and the if not ok_flag statement seemed to iron everything out. You don't really need those since as soon as ok_flag goes to False the loop terminates.

python opencv: destroyallwindow does not work

maybe its the copy of the mentioned question but I followed the first comment and got it solved by using terminal but someone need to find and tell why jupyter causes such problem.

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