python海龟画图继承与ondrag练习

"""python海龟画图继承与ondrag练习.py
本程序新建Durtle类，生成的拖动角色会换一个造型，松开它会隐藏
能读懂以下代码说明你的python海龟画图上了一个大台阶了。

"""
from turtle import *

class Durtle(Turtle):
    def __init__(self,images):
        Turtle.__init__(self,visible=False)
        self.begin_drag = 0                  # 拖的标志
        self.penup()
        self.images = images                 # 造型列表
        self.index = 0                       # 初始造型索引
        self.amounts = len(images)           # 造型数量

        "设定初始造型"
        self.image = self.images[self.index] # 当前造型
        self.shape(self.image)               # 设定造型
        self.st()                            # 显示
            
        self.ondrag(self.act1)  
        self.onrelease(self.act2)
        
    def alt_costume(self):
        "切换到下一个造型"
        if self.begin_drag == 0:
            self.index = self.index + 1
            self.index = self.index % self.amounts
            self.image = self.images[self.index]
            self.shape(self.image)
        self.begin_drag += 1        
                
    def act1(self,x,y):
        """切换到下一个造型，定位到鼠标指针坐标"""
        self.alt_costume()
        self.goto(x,y)  
        
    def act2(self,x,y):
        self.ht()
        self.goto(10000,10000)         # 走你,扔到远远的一个地方去眼不见为净
        self.begin_drag = 0
        #print("松开")        
          
if __name__ == "__main__":

    images = "dog2-a.gif","dog2-b.gif","dog2-c.gif"

    width,height = 480,360
    screen = Screen()
    screen.setup(width,height)
    screen.delay(0)
    [screen.addshape(image) for image in images]

    d = Durtle(images) 

    screen.mainloop()