Layers are storage places for graphic objects in a manager.
Each layer, with its graphic objects, is unique to a single
manager and can only be controlled by this manager.
When you store graphic objects in layers, you indicate
their placement throughout multiple layers. When you display graphic
objects stored in multiple layers, you present layer contents in a
series of one or several views, with each view controlled by and specific
to the same manager.
Various methods let you manipulate layers or the objects
that they own. When redrawing takes place, a layer with the number
N is placed in front of layers with numbers from N-1 to zero.
Inherent to the notion of layers is the concept of visual
hierarchy among graphic objects stored in layers and displayed in
views. In general, graphic objects of a more static nature, such as
objects that might serve as shading or background for your Rogue Wave JViews programs, should be put in a lower
layer of the manager. Those graphic objects of a dynamic nature, such
as objects with which users interact, should typically be put in a
higher layer so that they are not hidden.