The Graphical Editing Framework (GEF) provides a foundation for building rich, interactive user interfaces which are not easily built using native widgets found in the base Eclipse platform.
This guide provides an architectural overview of the Graphical Editing Framework. The reader should have working knowledge of the Eclipse platform.
The GEF component is separated into three plug-ins:
Draw2d (org.eclipse.draw2d) - the lightweight toolkit for 
	painting and layout on an SWT Canvas
GEF (org.eclipse.gef) - an interactive MVC framework built 
	on top of Draw2d
Zest (org.eclipse.zest) - a visualization toolkit built 
	on top of Draw2d
Notice that "GEF" can refer to the entire component (2 plug-ins), or just to the plug-in org.eclipse.gef.