Control modules for incorporating interaction in prefuse Displays. Examples include clicking a node to make it the new focus, dragging nodes to change their position, and performing pan and zoom operations. To add one of these controls to a visualization, create a new instance of the desired control and register it using the {@link prefuse.Display#addControlListener(Control)} method of the {@link prefuse.Display} class. Custom Controls can easily be constructed by implementing the {@link prefuse.controls.Control} interface, or, more conveniently, by subclassing the {@link prefuse.controls.ControlAdapter} class.