SimpleGesture

A simple, easy to use GWT and Vaadin component for gesture recognition.

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SimpleGesture is a Vaadin (and plain GWT) component for mouse gesture recognition. It uses a simple, but accurate, algorithm for gesture recognition, which represents the gesture as a human (well, programmer) readable string.

The gesture is encoded with numbers representing directions (left-right would be "40", see screenshot), and matching is done using the Levenshtein distance algorithm, which also tells you how closely the gesture was matched.

SimpleGesture also supports recording and detection of similar gestures.

See links for more details, and a demo.

Sample code

        // Set up some initial gestures
        SimpleGesture sg.addGesture("5443", "Counter clockwise"); // nw, w, w, sw
        sg.addGesture("7001", "Clockwise"); // ne, e, e, se
        sg.addGesture("321076543", "Circle"); // etc
        sg.addGesture("43210134", "Squiggle");

        // The listener that reacts to gestures - we'll just show the gesture
        // name as a notification.
        sg.addListener(new SimpleGesture.GestureListener() {
            public void gesture(GestureEvent event) {
                if (sg.isRecordMode()) {
                    sg.setRecordMode(false);
                    record.setCaption("Record gesture");
                    getMainWindow().addComponent(
                            new AddGesture(event.getMoved()));
                } else {
                    getMainWindow()
                            .showNotification(event.getData().toString());
                }
            }
        });
        // The component is invisible but needs to be in the layout anyway.
        mainWindow.addComponent(sg);

Links

• Project on Google Code
• Vaadin forum thread
• Blogpost with details
• Live demo

Compatibility