PysimpleGUIを用いたOpenCVのカメラ画像表示

import PySimpleGUI as sg
import cv2
import numpy as np

"""
Demo program that displays a webcam using OpenCV
"""

def main():

    sg.theme('Black')

    # define the window layout
    layout = [
            [sg.Text('Realtime movie', size=(40, 1), justification='center', font='Helvetica 20',key='-status-')],
            [sg.Image(filename='', key='image')],
            [sg.Button('Record', size=(10, 1), font='Helvetica 14'),
             sg.Button('Stop', size=(10, 1), font='Helvetica 14'),
             sg.Button('Exit', size=(10, 1), font='Helvetica 14'), ]
            ]

    # create the window and show it without the plot
    window = sg.Window('Realtime movie',
                       layout, location=(800, 400))

    # ---===--- Event LOOP Read and display frames, operate the GUI --- #

    recording = False

    while True:
        event, values = window.read(timeout=20)
        if event in (None, 'Exit'):
            break

        elif event == 'Record':
            window['-status-'].update("Record")
            cap = cv2.VideoCapture(0,cv2.CAP_DSHOW) #1
            # cap = cv2.VideoCapture(0)
            recording = True

        elif event == 'Stop':
            window['-status-'].update("Stop")
            recording = False
            img = np.full((480, 640), 0)
            # this is faster, shorter and needs less includes
            imgbytes = cv2.imencode('.png', img)[1].tobytes()
            window['image'].update(data=imgbytes)
            cap.release() #2
            cv2.destroyAllWindows()

        if recording:
            ret, frame = cap.read()
            if ret is True:
                imgbytes = cv2.imencode('.png', frame)[1].tobytes() 
                window['image'].update(data=imgbytes)

    window.close()

if __name__ == '__main__':
    main()