问Pygame退出全屏模式将窗口设置为屏幕外

EN

import pygame
from pygame.locals import *

pygame.init()

screen = pygame.display.set_mode((0, 0), pygame.FULLSCREEN)

run = True
while run:

    for event in pygame.event.get():

        if event == pygame.QUIT:
            run = False

        if event.type == pygame.KEYDOWN:

            # Exit fullscreen with escape key
            if event.key == pygame.K_ESCAPE:

                if screen.get_flags() & FULLSCREEN:
                    pygame.display.set_mode((400, 400))
                else:
                    pygame.display.set_mode((0, 0), FULLSCREEN)

import os

# .........
                if screen.get_flags() & FULLSCREEN:
                    os.environ['SDL_VIDEO_CENTERED'] = '1'
                    pygame.display.set_mode((400, 400))
                else:
                    pygame.display.set_mode((0, 0), FULLSCREEN)