篮球自动弹跳

import sys  
import pygame  

pygame.init()  
size = width, height = 640, 480  
screen = pygame.display.set_mode(size)  
color = (0, 0, 0)  

ball = pygame.image.load("ball.png")  
ballrect = ball.get_rect()  

speed = [5, 5]  
clock = pygame.time.Clock()  
while True:
    clock.tick(60) 
    
    for event in pygame.event.get():
        if event.type == pygame.QUIT:  
            sys.exit()

    ballrect = ballrect.move(speed)
    if ballrect.left < 0 or ballrect.right > width:
        speed[0] = -speed[0]
    if ballrect.top < 0 or ballrect.bottom > height:
        speed[1] = -speed[1]

    screen.fill(color)  
    screen.blit(ball, ballrect)  
    pygame.display.flip()  

pygame.quit()