Cocoa® Programming

The Text System Architecture

Many classes are used to implement the complete text system. The classes are organized using the Model-View-Controller (MVC) design introduced in the “Model-View-Controller” section of Chapter 6, “Cocoa Design Patterns.” The text to be displayed and the attributes that affect that display are stored in the model. The visual representation of text and handing user input are the responsibility of the view layer. The logic that links the model and view is implemented in the controller layer. Figure 11.1 shows the classes used by the text system, and their role in the Model-View-Controller design:

Figure 11.1. Many classes interact to implement Cocoa’s text system.

This Model-View-Controller design reduces dependencies ...