import  pygame
import  random
WIDTH =  800 
HEIGHT =  600 
WHITE =  ( 255 ,  255 ,  255 ) 
BLACK =  ( 0 ,  0 ,  0 ) 
RED =  ( 255 ,  0 ,  0 ) 
GREEN =  ( 0 ,  255 ,  0 ) 
BLUE =  ( 0 ,  0 ,  255 ) 
class  Ball : def  __init__ ( self) : self. radius =  10 self. speed =  [ random. randint( 2 ,  4 ) ,  random. randint( 2 ,  4 ) ] self. color =  REDself. rect =  pygame. Rect( 400 ,  300 ,  self. radius *  2 ,  self. radius *  2 ) def  move ( self) : self. rect. move_ip( self. speed[ 0 ] ,  self. speed[ 1 ] ) if  self. rect. left <=  0  or  self. rect. right >=  WIDTH: self. speed[ 0 ]  =  - self. speed[ 0 ] if  self. rect. top <=  0  or  self. rect. bottom >=  HEIGHT: self. speed[ 1 ]  =  - self. speed[ 1 ] def  draw ( self,  screen) : pygame. draw. circle( screen,  self. color,  self. rect. center,  self. radius) 
pygame. init( ) 
screen =  pygame. display. set_mode( ( WIDTH,  HEIGHT) ) 
pygame. display. set_caption( "壁球小游戏" ) 
ball =  Ball( ) 
running =  True 
clock =  pygame. time. Clock( ) while  running: for  event in  pygame. event. get( ) : if  event. type  ==  pygame. QUIT: running =  False ball. move( ) screen. fill( BLACK) ball. draw( screen) pygame. display. flip( ) clock. tick( 60 ) 
pygame. quit( )