VisClass: 2 The Visible Class Tree

As stated earlier, the visible class tree consists of four classes.

VisClass: This is the parent class of the visible tree. It contains the basic functionality common to every visible object and is the subject of this chapter.
VisCompClass: A subclass of VisClass , this class has the added ability to have and arrange children in the visible tree. It has sophisticated geometry management functions built in and can be used as an organizational object.
VisContentClass: A subclass of VisCompClass , this class is used only as the content of a GenView. The VisContent has default handlers for many messages sent out by the view, and it interacts with the view window to display the visible object tree. Every visible object tree, to be displayed in a GenView, must have a VisContent as its root object.
VisTextClass: This class, not discussed in this chapter, is a visible version of the GenTextClass . It provides a nearly full-featured word processing object that can be put in the visible tree.

The first three of these classes are used extensively by many applications.