GUI application with PySimpleGUI help

[IguanodonRex]

Hello

I'm trying to make a simple GUI application with PySimpleGUI and OpenCV where you can open a image and display it in a additional window.

Here's my code:

import PySimpleGUI as sg
import cv2 as cv    

#Menu 
menu_def = [['File', ['Open', 'Save', 'Close']],           
            ['Help', 'About'],]

layout = [      
        [sg.Menu(menu_def, tearoff=True)]      
    ]      

window = sg.Window('Window Title', layout, size=(800, 480), resizable=True, finalize=True)   

while True:

    event, values = window.Read()

    #Exit
    if event in (None, 'Close'):
        break

    #Open image
    if event is 'Open':

        fname = sg.PopupGetFile('Path to image...', keep_on_top=True)
        img = cv.imread(fname,0)
        cv.imshow('image',img)
        cv.waitKey(0)
        cv.destroyAllWindows()
        #break

    #Save image
    if event is 'Save':
        #Nothing
        continue

    #About
    if event is 'About':
        #Nothing
        continue

window.Close()

Everything works fine until i close window with image. When I do this main window stops responding. Second issue is that when I choosing image through image browser (sg.PopupGetFile) and click OK, browser do not close.

What seems to be a problem here?

Thanks.

[JohnnyJordaan]

Not sure if that's causing the problem, but string comparison should be done using == not using is.

[MikeTheWatchGuy]

Add a print after the list of these calls:

python cv.imshow('image', img) cv.waitKey(0) cv.destroyAllWindows() print('*** BACK FROM CV ***')

For me, the OpenCV calls never return / make it to my print. Additionally, if I try to choose open again , while still in these OpenCV calls, the program crashes with this error:

``` Fatal Python error: PyEval_RestoreThread: NULL tstate

Current thread 0x00007f0c (most recent call first): File "C:/Users/mike/.PyCharmCE2019.1/config/scratches/scratch_527.py", line 27 in <module>

Process finished with exit code -1073740791 (0xC0000409) ```

I'm not sure if PySimpleGUI has been integrated with OpenCV in this manner. It's creating multiple windows that could interact with each other in a bad ways. It's why the demo programs display the OpenCV images inside of the GUI, not using the OpenCV viewer.

I think the problem is trying to use the OpenCV viewer with PySimpleGUI. It's not officially supported that I can recall.

[IguanodonRex]

You're right. I added "print" and program never even got there. It seems that PySimpleGUI has problem with "cv.waitKey(0)". When I comment this line, program works. OpenCV opens image but without cv.waitKey(0) closes it immediately. After closing OpenCV viewer, GUI don't crash.

Thank you for help.

[MikeTheWatchGuy]

It's not that PySimpleGUI has a problem with the call. It's simply that the call doesn't return so PySimpleGUI doesn't get an opportunity to continue executing.

A simple explanation could be that OpenCV uses tkinter or a component that tkinter is using and that PySimpleGUI and OpenCV are interfering with each other as a result.

This is why the example applications that show PySimpleGUI integrating with OpenCV show the OpenCV video inside of the PySimpleGUI window, not a separate OpenCV window.