使用事件处理创建一个简单的绘图实例程序 python

import Tkinter
class mybutton:#定义按钮类
def __init__(self,root,canvas1,label1,type):#类初始化canvas1，label1是MyCanvals，mylabel的实例，因此可以使用类中的方法
self.root=root#保存引用值
self.canvas1=canvas1
self.label1=label1
if type==0:#根据类型创建按钮
button=Tkinter.Button(root,text='huaxian',command=self.DrawLine)
elif type==1:
button=Tkinter.Button(root,text='huashanxing',command=self.DrawArc)
elif type==2:
button=Tkinter.Button(root,text='huajuxing',command=self.DrawRec)
else:
button=Tkinter.Button(root,text='huatuoyuan',command=self.DrawOval)
button.pack(side='left')
def DrawLine(self):#DrawLine按钮事件处理函数
self.label1.text.set('Draw Line')
self.canvas1.SetStatus(0)#把status赋值，便于根据status的值进行画图
def DrawArc(self):
self.label1.text.set('Draw Arc')
self.canvas1.SetStatus(1)
def DrawRec(self):
self.label1.text.set('Draw Rectangle')
self.canvas1.SetStatus(2)
def DrawOval(self):
self.label1.text.set('Draw Oval')
self.canvas1.SetStatus(3)
class MyCanvals:
def __init__(self,root):
self.status=0
self.draw=0
self.root=root
self.canvas=Tkinter.Canvas(root,bg='red',width=600,height=480)#生成canvas组件
self.canvas.pack()
self.canvas.bind('<ButtonRelease-1>',self.Draw)#绑定事件到左键
self.canvas.bind('<Button-2>',self.Exit)#绑定事件到中键
self.canvas.bind('<Button-3>',self.Del)#绑定事件到右键
self.canvas.bind_all('<Delete>',self.Del)#绑定事件到delete键
self.canvas.bind_all('<KeyPress-d>',self.Del)#绑定事件到d键
self.canvas.bind_all('<KeyPress-e>',self.Exit)#绑定事件到e键
def Draw(self,event):#绘图事件处理函数
if self.draw==0:#判断是否绘图，先记录起始位置
self.x=event.x
self.y=event.y
self.draw=1
else:#根据self.status绘制不同的图形
if self.status==0:
self.canvas.create_line(self.x,self.y,event.x,event.y)
self.draw=0
elif self.status==1:
self.canvas.create_arc(self.x,self.y,event.x,event.y)
self.draw=0
elif self.status==2:
self.canvas.create_rectangle(self.x,self.y,event.x,event.y)
self.draw=0
else:
self.canvas.create_oval(self.x,self.y,event.x,event.y)
self.draw=0
def Del(self,event):#按下右键或者d键删除图形
items=self.canvas.find_all()
for i in items:
self.canvas.delete(i)
def Exit(self,event):#按下中键或者e键退出
self.root.quit()
def SetStatus(self,status):#设置绘制的图形
self.status=status
class mylabel:#定义标签类
def __init__(self,root):
self.root=root
self.canvas1=canvas1
self.text=Tkinter.StringVar()#生成标签引用变量
self.text.set('Draw Line')
self.label=Tkinter.Label(root,textvariable=self.text,fg='blue',width=50)#生成标签
self.label.pack(side='left')
root=Tkinter.Tk()#生成主窗口
canvas1=MyCanvals(root)#生成实例
label1=mylabel(root)#生成实例
mybutton(root,canvas1,label1,0)
mybutton(root,canvas1,label1,1)
mybutton(root,canvas1,label1,2)
mybutton(root,canvas1,label1,3)
root.mainloop()#进入消息循环