/**
* Called when an action event occurs, in this case the 'Invert Terrain' button is the only
* component which generates an action event
*
* @param e The action event generated
*/
public void actionPerformed(ActionEvent e) {
if (e.getSource().equals(btnApply)) {
parent.amendLog("Applying filter: " + toString());
parent.setHeightMap(apply(false));
}
}
