用Pygame绘制移动的矩形

#moving rectangle project

import pygame

from pygame.locals import *

pygame.init()

screen = pygame.display.set_mode((600,500))

pygame.display.set_caption("Drawing Rectangles")

pos_x = 300

pos_y = 250

vel_x = 2

vel_y = 1

while True:

    for event in pygame.event.get():

        if event.type in (QUIT,KEYDOWN):

            pygame.quit()

    screen.fill((0,0,200))

    # move the rectangle

    pos_x += vel_x

    pos_y += vel_y

    # keep rectangle on the screen

    if pos_x > 500 or pos_x < 0:

        vel_x = -vel_x

    if pos_y > 400 or pos_y < 0:

        vel_y = -vel_y

    # draw the rectangle

    color = 255,255,0

    width = 0 #solid fill

    pos = pos_x,pos_y,100,100

    pygame.draw.rect(screen,color,pos,width)

    pygame.display.update()