The Sketch project was created to support a more flexible modeling activity in Eclipse, enriching user's interaction with graphical editors by taking advantage from the capabilities provided by touch/tablet devices using free-hand sketching recognition.
This project was just provisioned. You can see the proposal here
Sketch is able to recognize user's input and create elements on graphical editors built with GMF and GEF
It's possible to add sketching capabilities to GMF/GEF editors by just extending Sketch's tool -- the API listen to user's input and returns the recognition results.
The sample editor shipped with Sketch has form recognition and annotation capabilities -- you may use them as is on your own editor.
It's possible to represent any element in infinite ways
Sketch is currently under code review and refactoring. You may access it's Git repository