“Dibujar caja con mouse en la imagen en Canvas Tkinter” Código de respuesta

Dibujar caja con mouse en la imagen en Canvas Tkinter

import PIL.Image
import Image
import ImageTk
from Tkinter import *    


class ExampleApp(Frame):
    def __init__(self,master):
        Frame.__init__(self,master=None)
        self.x = self.y = 0
        self.canvas = Canvas(self,  cursor="cross")

        self.sbarv=Scrollbar(self,orient=VERTICAL)
        self.sbarh=Scrollbar(self,orient=HORIZONTAL)
        self.sbarv.config(command=self.canvas.yview)
        self.sbarh.config(command=self.canvas.xview)

        self.canvas.config(yscrollcommand=self.sbarv.set)
        self.canvas.config(xscrollcommand=self.sbarh.set)

        self.canvas.grid(row=0,column=0,sticky=N+S+E+W)
        self.sbarv.grid(row=0,column=1,stick=N+S)
        self.sbarh.grid(row=1,column=0,sticky=E+W)

        self.canvas.bind("<ButtonPress-1>", self.on_button_press)
        self.canvas.bind("<B1-Motion>", self.on_move_press)
        self.canvas.bind("<ButtonRelease-1>", self.on_button_release)

        self.rect = None

        self.start_x = None
        self.start_y = None

        self.im = PIL.Image.open("logo.png")
        self.wazil,self.lard=self.im.size
        self.canvas.config(scrollregion=(0,0,self.wazil,self.lard))
        self.tk_im = ImageTk.PhotoImage(self.im)
        self.canvas.create_image(0,0,anchor="nw",image=self.tk_im)   


    def on_button_press(self, event):
        # save mouse drag start position
        self.start_x = self.canvas.canvasx(event.x)
        self.start_y = self.canvas.canvasy(event.y)

        # create rectangle if not yet exist
        if not self.rect:
            self.rect = self.canvas.create_rectangle(self.x, self.y, 1, 1, outline='red')

    def on_move_press(self, event):
        curX = self.canvas.canvasx(event.x)
        curY = self.canvas.canvasy(event.y)

        w, h = self.canvas.winfo_width(), self.canvas.winfo_height()
        if event.x > 0.9*w:
            self.canvas.xview_scroll(1, 'units') 
        elif event.x < 0.1*w:
            self.canvas.xview_scroll(-1, 'units')
        if event.y > 0.9*h:
            self.canvas.yview_scroll(1, 'units') 
        elif event.y < 0.1*h:
            self.canvas.yview_scroll(-1, 'units')

        # expand rectangle as you drag the mouse
        self.canvas.coords(self.rect, self.start_x, self.start_y, curX, curY)    

    def on_button_release(self, event):
        pass    

if __name__ == "__main__":
    root=Tk()
    app = ExampleApp(root)
    app.pack()
    root.mainloop()