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Tracking Mouse Actions for Many Canvas Objects

April 15, 1998 | Fredrik Lundh

Instead of binding event handlers to each and every item, you can use a single event handler and then use find_withtag(CURRENT) to get the target item. An example:

from Tkinter import *
from random import randint

root = Tk()

canvas = Canvas(root, width=200, height=200)
canvas.pack()

def click(event):
    if canvas.find_withtag(CURRENT):
	canvas.itemconfig(CURRENT, fill="blue")
	canvas.update_idletasks()
	canvas.after(200)
	canvas.itemconfig(CURRENT, fill="red")

for i in range(100):
    x, y = randint(0, 200-1), randint(0, 200-1)
    canvas.create_oval(x-5, y-5, x+5, y+5, fill="red")

canvas.bind("<Button-1>", click)

root.mainloop()