__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()