The Scene-View-Item architecture

As it was mentioned in the introduction, the Graphics View Framework in Qt (or simply Qt from now on) divides possible graphics-related objects that you need to deal with into three major categories, which are Scene, View, and Items. Qt includes classes with quite noticeable names to handle each part of this architecture. Even though in theory it's easy to separate them from each other, in practice, they are very much intertwined. This means we cannot really dig deep into one of them without mentioning the others. Clear out one part of the architecture and you'll have no graphics at all. Also, taking another look at the architecture, we can see the model-view design pattern where the model (in this case, the scene) is totally unaware of how, or which part of it is displayed. As it's called in Qt, this is an Item-based approach to...