pygame是用来写2D游戏的。

实现斜线运动，无非是在x和y两个方向上分运动的合成。x方向上的运动，当撞到边界的时候取相反速度就好了。

这里是用网球王子中的图片，以及一个网球实现，效果截图：

注意看，那个方块形状的网球是会动的，撞到边界就反弹，时刻匀速（这情况太理想了。。。）

代码：

# coding:utf-8bgimg = 'teni.jpg'spimg = 'ball.jpg'import pygamefrom pygame.locals import *from sys import exitpygame.init()screen = pygame.display.set_mode((640, 480), 0, 32)bg = pygame.image.load(bgimg).convert()sp = pygame.image.load(spimg).convert_alpha()clock = pygame.time.Clock()x, y =100., 100.speed_x, speed_y = 133., 170.while True:    for event in pygame.event.get():        if event.type == QUIT:            exit()    screen.blit(bg, (0, 0))    screen.blit(sp, (x, y))    time_passed = clock.tick(30)  # 设定最大FPS不超过30    # FPS：Frame per second    time_passed_seconds = time_passed / 1000.0    x += speed_x * time_passed_seconds    y += speed_y * time_passed_seconds    if x > 640 - sp.get_width():        speed_x = -speed_x        x = 640 - sp.get_width()    elif x < 0:        speed_x = - speed_x        x = 0.    if y > 480 - sp.get_height():        speed_y = -speed_y        y = 480 - sp.get_height()    elif y < 0:        speed_y = -speed_y        y = 0    pygame.display.update()