pygame学习之绘制移动的矩形

 import pygame
 from pygame.locals import *

 pygame.init()
 screen = pygame.display.set_mode((600, 500))
 pygame.display.set_caption("drawing a rectangle")
 pos_x = 300
 pos_y = 250
 vel_x = 2                            # 设置速度变量
 vel_y = 1
 while True:
     for event in pygame.event.get():
         if event.type in (QUIT, KEYDOWN):
             exit()
     screen.fill((0, 0, 200))
     pos_x += vel_x
     pos_y += vel_y

     if pos_x > 500 or pos_x < 0:
         vel_x = -vel_x                       # 让矩形在窗口范围内移动
     if pos_y > 400 or pos_y < 0:
         vel_y = -vel_y
     color = 255, 255, 0
     width = 0
     pos = pos_x, pos_y, 100, 100             # 矩形长和宽都为100
     pygame.draw.rect(screen, color, pos, width)
     pygame.display.update()