title: Is there a way to check for changes in Python Tk windows?
body: <p>I have a program that changes the location of objects on a tkinter canvas, depending on the size of the window. This works, but it is run every loop and slows down the program dramatically when there are lots of objects, as it deletes and re-draws them.</p>
  
  <p>Is there a way to check for changes in the size of a window, so that it only has to be run once, when it needs to be?</p>