pygame经典sprite精灵类

import cStringIO, base64import pygamefrom pygame.locals import *class Ball(pygame.sprite.Sprite):    def __init__(self, color, initial_position):        pygame.sprite.Sprite.__init__(self)        ball_file = cStringIO.StringIO(base64.decodestring("""iVBORw0KGgoAAAANSUhEUgAAABkAAAAZCAYAAADE6YVjAAAAGXRFWHRTb2Z0d2FyZQBBZG9iZSBJbWFnZVJlYWR5ccllPAAABBJJREFUeNqsVj2PG1UUvfPp8XictXfHa+9mlyJCNEQRWiToqACJAgGCLqJNlQZR0IFEj8RPSJkGGooUpEWJkGhR0tAAElI2tsfjjxnPjIdz7oyDF2wSUK72yN43793z7rkfY8N2HFmbbVliGIYiyzIpy1Isy3oHeMswzLOyXJ2tVit9VhTFAxz5Cfge+A7IZIcZmySObQudwIE0veanraB1w/O8l5x6D9eXy6UkSaJYLBa6BvsNuAV8uY3sCQlvX4LANM0Xw/Dgdhj2Xm02m+K6LqPRPXmeS5qmMp/PZTabyXQ6lclkosS1/QJcB+5vkthrAkoAuc4uHx//0B8MvCAIxG/5jEg0kpIkmcwXicTxBIhlHWEURXoedgW4B3wIfHuBJM9yMQ3j5PTk5N7g6MjtdrrS3e9Ku90GUUvc2hkdMYJx5IvnNRC19UReRlRLR/sGeB34UUkMJBcJlcHg6K4SdDvS7/el1+tJp7MnQdCWRqMhDGWZLmWCCFog9rBmGBYc50rOKON4uqkSC+IQSC3moeX7N09PX/i4AwLkAoQDxeFhHziU8CCUzt6e+EFLc2QaJi4mFQHykQLZMpME+WJF1sabdYA7Nq4jQbv9OZPs+75cgkSMYH9/X6PhJ9dpTLjruFLkBRyjACBd1BoLzzY8T3O0IRntJvCZDXsTTnq262CzrzmgRHu4+QEIQhAxNzRWU1mTxfjOwvBIAOlIYNnWtja5bqM33mN/sBEdx9bNPOQ1PWlqZJdAFKoMrEI6R+9gj6t7cUl1zjKnjFvsfaybr1Uqlv94ypXSKCud+aefpezs7O3LL9s4c5U65gCrhGDDpUkqyWIuU1STweNlJRe7nAlmA+ZaVbnmiD4KFNEWC+3VqjB5YImDdMA+YKONx2OVgxefojRL8CzmCxkOhxLhWYy+mGIvz6RKmv096X91PErP4Byazapbs3vZB45bVQqTzBzQkjQBQSTnjx7JcDTCRSLkKNY9SbKACsttHKZdrIqHILnGCNhoDU0qG83U5mNUVTOKShRPYo3m8fAcnT/S/3mWFy2KrXKNOFbuI+Rr1FvLsB731Ho2m2pU7I1Sx8pSHTLaESIZjob6nfso2w77mSR3IMsNzh4mmLOIBAkO6fjAgESdV1MYiV4kiUZHRDjD3E0Qza580D+rjsUdAQEj4fRl8wUkqBttPeo5RlJIuB71jIASc8D+i4W8IoX8CviC5cuI+JlgpLsgcF1ng6RQyaoX1oWX1i67DTxe9w+9/EHW9VOrngCWZfNFpmvVWOfUzZ/mfG0HwHBz4ZV1kz8nvLuL+YPnRPDJ00J8A/j9fzrnW+sjeUbjbP8amDyj86z+tXL5PwzOC4njj4K3gavA8cazczYacLd+p/+6y8mfAgwAsRuLfp/zVLMAAAAASUVORK5CYII="""))        self.image = pygame.image.load(ball_file, 'file').convert_alpha()        self.rect = self.image.fill(color, None, BLEND_ADD)        self.rect.topleft = initial_positionpygame.init()# screen = pygame.display.set_mode([350, 350])# ball = Ball((255, 0, 0), (100, 100))# screen.blit(ball.image, ball.rect)# pygame.display.update()# while pygame.event.poll().type != KEYDOWN:#     pygame.time.delay(10)class MoveBall(Ball):    def __init__(self, color, initial_position, speed, border):        super(MoveBall, self).__init__(color, initial_position)        self.speed = speed        self.border = border        self.update_time = 0     def update(self, current_time):        if self.update_time < current_time:            if self.rect.left < 0 or self.rect.left > self.border[0] - self.rect.w:                self.speed[0] *= -1            if self.rect.top < 0 or self.rect.top > self.border[1] - self.rect.h:                self.speed[1] *= -1             self.rect.x, self.rect.y = self.rect.x + self.speed[0], self.rect.y + self.speed[1]            self.update_time = current_time + 10 pygame.init()screen = pygame.display.set_mode([350, 350]) balls = []for color, location, speed in [([255, 0, 0], [50, 50], [2,4]),                        ([0, 255, 0], [100, 100], [3,2]),                        ([0, 0, 255], [150, 150], [4,3])]:    balls.append(MoveBall(color, location, speed, (350, 350))) while True:    if pygame.event.poll().type == QUIT: break     screen.fill((0,0,0,))    current_time = pygame.time.get_ticks()    for b in balls:        b.update(current_time)        screen.blit(b.image, b.rect)    pygame.display.update()