The Eclipse Graphical Modeling Project (GMP) provides a set of generative components and runtime infrastructures for developing graphical editors based on EMF and GEF.
It consists in
GMF Notation: a model to store diagrams
GMF Runtime: a runtime API that is used to manage graphical diagram in using the MVC pattern.
GMF Tooling: some tools to generate diagrams by editing some configurable model files
Graphiti: an alternative to the GMF stack to handle diagrams.