python写的屏保程序

__author__ = 'ChenYan'

from random import randint
from tkinter import *

class Randball():
def __init__(self, canvas, scrnwidth, scrnheight):
#初始化画布
self.canvas = canvas
#初始化球的圆心坐标
self.x_pos = randint(80, int(scrnwidth))
self.y_pos = randint(80, int(scrnheight))
#球移动的距离
self.x_move = 10
self.y_move = 10
#整个屏幕的宽和高
self.scrnwidth = scrnwidth
self.scrnheight = scrnheight
#初始化球的半径
self.radius = randint(40, 70)
#随机产生球的颜色
rc = lambda :randint(0,255)
self.color = '#%02x%02x%02x' % (rc(), rc(), rc())

def create_ball(self):
#计算得到用于创建球的四个坐标
x1 = self.x_pos - self.radius
y1 = self.x_pos - self.radius
x2 = self.x_pos + self.radius
y2 = self.x_pos + self.radius
#画球
self.item = self.canvas.create_oval(x1, y1, x2, y2, fill=self.color, outline=self.color)

def move_ball(self):
'''按指定的距离移动球，如果球碰到障碍向相反的方向移动'''
self.x_pos += self.x_move
self.y_pos += self.y_move

if self.x_pos >= self.scrnwidth - self.radius:
self.x_move = -self.x_move
if self.y_pos >= self.scrnheight - self.radius:
self.y_move = -self.y_move
if self.x_pos < self.radius:
self.x_move = abs(self.x_move)
if self.y_pos < self.radius:
self.y_move = abs(self.y_move)
self.canvas.move(self.item, self.x_move, self.y_move)

class Screensaver():
balls = []
def __init__(self, ball_nums):
self.win = Tk()
self.width = self.win.winfo_screenwidth()
self.height = self.win.winfo_screenheight()
self.win.overrideredirect(True)
self.win.attributes('-alpha', 0.3)
#绑定事件，有任何动作退出屏保
self.win.bind('<Any-Button>', self.exit_screensaver)
self.win.bind('<Motion>', self.exit_screensaver)
self.canvas = Canvas(self.win, width=self.width, height=self.height, bg='#00FFFF')
self.canvas.pack()

for i in range(0,ball_nums):
ball = Randball(self.canvas, scrnwidth=self.width, scrnheight=self.height)
ball.create_ball()
self.balls.append(ball)
self.run_screensaver()
self.win.mainloop()

def run_screensaver(self):
for ball in self.balls:
ball.move_ball()
self.canvas.after(20, self.run_screensaver)

def exit_screensaver(self, event):
self.win.destroy()

def main():
Screensaver(15)

if __name__=='__main__':
main()