Delete an instance of a class

Question

I've already asked a similar question here and I received quite a helpful reply. But since then I've modified my code, now it is more optimized I guess, it is supposed to be more flexible, but the same problem persists. I can not delete an instance of the class.

What I'm trying to do is to create a circle (on a left-click) and then I expect the program to delete the circle (on a right-click).

My code:

from tkinter import *

class Application:
    def __init__(self):
        self.fen = Tk()
        self.fen.title('Rom-rom-roooooom')
        self.butt1 = Button(self.fen, text = ' Quit ', command = self.fen.quit)
        self.can1 = Canvas(self.fen, width = 300, height = 300, bg = 'ivory')
        self.can1.grid(row = 1)
        self.butt1.grid(row = 2)
        self.fen.bind("<Button-1>", self.create_obj)
        self.fen.bind("<Button-3>", self.delete_obj)
        self.fen.mainloop()
    def create_obj(self, event):
        self.d = Oval()
        self.can1.create_oval(self.d.x1, self.d.y1, self.d.x2, self.d.y2, fill='red', width = 2)
    def delete_obj(self, event):
        self.can1.delete(self.d)


class Oval:

    def __init__(self):
        self.x1 = 50
        self.y1 = 50
        self.x2 = 70
        self.y2 = 70



appp = Application()

so, once again, the problem is that here I can not delete the object:

def delete_obj(self, event):
        self.can1.delete(self.d)

One more question. Given the fact that I'm just a begginer I don't know if I chose the right approach as far as class organisation is concerned. Does it look like a well-organized code or should I change anything at this stage already?

Answer 1

These two lines:

self.d = Oval()
self.can1.create_oval(self.d.x1, self.d.y1, self.d.x2, self.d.y2, fill='red', width = 2)

create a new Oval object, assign that object to the name self.d, then create an oval on self.can1 that is completely unrelated (aside from having the same dimensional attributes) from the Oval object assigned to self.d. Instead, I think you want:

o = Oval()
self.d = self.can1.create_oval(o.x1, o.y1, o.x2, o.y2, fill='red', width = 2)

This retains a reference to the object on the Canvas, so you will be able to delete it. Note that Oval is more-or-less-completely pointless, as all it does is provide the dimensions.