[udig-devel] Overlay utility classes

[Jody Garnett <jgarnett@xxxxxxxxxxxxxxx>]

I have added a couple of utility classes to net.refractions.udig.ui:
- DecoratorOverlayIcon
- OverlayCache

This is a working implemenation of the the idea of image decorators. The 
superclass
CompositeImageDescriptor is public but any eclipse implementaiton is 
part of an
internal package (and thus not API).

These two classes can be used when writing your own ILabelProvider or 
ILabelDecorator
to instrument a Icon with existing markup to communicate state, status, 
edited etc ...

Cheers,
Jody