The diva.sketch demo
The sketch demo demonstrates a sketch-based user interface with embedded gesture recogntion. In the default setup, two types of gestures are supported, check and scribble. The user can draw a check on a figure to select it. When a figure is selected, a set of grab handles appear around it which can be used to rescale the figure. The user can also click on the figure and drag it around. To delete a figure, simply scribble over it. Undo and redo of symbols are supported and can be accessed from the edit menu. The resulting sketch can be saved in a file with ".sk" extension.
The following picture shows the selection and deletion gestures. The recognizer for the deletion gesture is direction independent, so the gesture can be drawn in any fashion. The recognition for the selection gesture is direction dependent, therefore the gesture has to be drawn in the same way as it is trained.
The gesture recognition in the demo currently support single-stroke gestures, which means that in order for a gesture to be recognized it has to be completed in one stroke (a path formed from pen down to pen up). The lack of multi-stroke gestures is not a shortcoming of the recognition archicture, but rather this particular recognizer implementation. See the package documentation for details.