编辑代码

# coding:utf-8
#JSRUN引擎2.0，支持多达30种语言在线运行，全仿真在线交互输入输出。 
from tkinter import *
from tkinter.filedialog import *
from tkinter.colorchooser import *

win_width=900
win_heigth=450

class Application(Frame):
    def __init__(self,master=None):
        super().__init__(master)
        self.pack()
        self.master = master
        self.createWidget()
        self.bgcolor= '#000000'
        self.fgcolor = '#ff0000'
        self.x = 0
        self.y=0
        self.lastDraw = 0
        self.Flag = False

    def createWidget(self):
        #画布
        self.canvas = Canvas(self,width=win_width,height=win_heigth*0.9,bg='black')
        self.canvas.pack()
        #按钮
        btn_pen = Button(root,text="画笔",name="pen")
        btn_pen.pack(side="left",padx="10")
        btn_rect = Button(root,text="矩形",name="rect")
        btn_rect.pack(side="left",padx="10")
        btn_clear = Button(root,text="清屏",name="clear")
        btn_clear.pack(side="left",padx="10")
        btn_erasor = Button(root,text="橡皮擦",name="erasor")
        btn_erasor.pack(side="left",padx="10")
        btn_line = Button(root,text="直线",name="line")
        btn_line.pack(side="left",padx="10")
        btn_lineArrow = Button(root,text="箭头",name="lineArrow")
        btn_lineArrow.pack(side="left",padx="10")
        self.btn_color = Button(root,text="颜色",name="color")
        self.btn_color.pack(side="left",padx="10")

        #将所有按钮都和eventManager绑定
        btn_line.bind_class('Button','<Button-1>',self.eventManager)
        self.canvas.bind('<ButtonRelease-1>',self.stopDraw)

        #问：为什么不用Button中的command 答：因为按了按钮之后不是马上操作，而是在画布上进行操作，所以应该按了按钮之后将画布与相应的操作进行绑定
        #画布事件绑定
    def eventManager(self,event):
        #获取是哪一个事件发生，也就是哪一个按钮被点击
        event_name = event.widget.winfo_name()
        print(event_name)
        if event_name == 'line':
            self.canvas.bind('<B1-Motion>',self.myLine)

    def stopDraw(self,event):
        self.Flag=False
        self.lastDraw = 0


    def myLine(self,event):
        self.canvas.delete(self.lastDraw)
        if str(self.Flag)=='False':
            self.Flag=True

        self.lastDraw = self.canvas.create_line(self.x,self.y,event.x,event.y,fill=self.fgcolor)
        



if __name__ == '__main__':
    root = Tk()
    root.title('画图')
    root.geometry(str(win_width)+"x"+str(win_heigth)+"+200+300")
    app = Application(master=root)
    root.mainloop()