pygame.display.update()

def draw():
    pygame.draw.circle(screen, (0, 0, 0), (250, 250), 125)
pygame.display.update()
button1 = Button(buttonwin, text='Draw', command=draw)
button1.pack(side=LEFT)
root.update()
while True:
    pygame.display.update()
root.update()
Embedding a Pygame window into a Tkinter or WxPython frame