Attributes, id and root

In Chapter 1, GUI Basics – Building an Interface, we distinguished between four main components for our Comic Creator: toolbox, drawing space, general options, and status bar. In this chapter these components will start to interact with each other and, therefore, we need to add some attributes to the classes of the project we created in the previous chapters. These attributes will reference different parts of the interface so they can interact. For example, the Toolbox class needs to have a reference to the DrawingSpace instance, so the ToolButton instances can draw their respective figures inside of it. The following diagram shows all the relationships that are created in the comiccreator.kv file:

Internal References of the Comic Creator

We also learned in Chapter 1, GUI Basics – Building an Interface that id lets us reference other widgets in the Kivy language.

Note

However, ids by themselves are not intended to be used outside of the Kivy language: that is the Python...