淡入淡出显示图形的两个函数

"""
   淡入淡出显示图形的两个函数,
   注意,在显示的过程中没有进行事件检测
"""

import pygame
from time import sleep
from pygame.locals import * 

def fade_in_image(screen,image):
    """淡入显示图像"""
    
    for a in range(0,256):
        image.set_alpha(a)
        screen.fill((0,0,0))
        screen.blit(image,(0,0))
        pygame.display.update()
        sleep(0.01)
        
def fade_out_image(screen,image):
    """淡出显示图像"""

    for a in range(255,-1,-1):        
        image.set_alpha(a)
        screen.fill((0,0,0))
        screen.blit(image,(0,0))
        pygame.display.update()
        sleep(0.01)

if __name__ == "__main__":
        
    screen = pygame.display.set_mode((480,360))
    cover = pygame.image.load("封面.png").convert()
    fade_in_image(screen,cover)
    fade_out_image(screen,cover)