Model.py - Patch67/Graphics GitHub Wiki

Model holds a reference to Controller so it can tell the controller when the data has changed.

Model also has a dirty property with a setter and getter which indicates if the data has changed.

Controller.title depends upon Model.dirty to tell it when the data has changed and there fore a save is required.

Model holds a single Graph.Group class which is a group containing all graphics objects of all types.

Model can never talk directly to View model never initiates communications with Controller. It is simply told by Controllerwhat to change something or is told to fetch some data.