/*
* CentralPointFilter.java
*
* Copyright (c) 2010, Ralf Biedert, DFKI. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301 USA
*
*/
package de.dfki.km.text20.util.filter.centralpoint;
import java.awt.Point;
import java.util.ArrayList;
import java.util.List;
import de.dfki.km.text20.services.trackingdevices.eyes.EyeTrackingEvent;
import de.dfki.km.text20.services.trackingdevices.eyes.util.wrapper.TrackingEventWrapper;
import de.dfki.km.text20.util.filter.AbstractFilter;
/**
* Collects functions all centralPoint filters use.
*
* @author rb
*
*/
public abstract class CentralPointFilter extends AbstractFilter {
/** Size of the backlog */
protected int backlogSize;
/** All points used to smooth */
final protected List<Point> lastPoints = new ArrayList<Point>();
/**
* Creates the filter with a given backlog size
*
* @param backlogSize
*/
public CentralPointFilter(final int backlogSize) {
this.backlogSize = backlogSize;
}
/* (non-Javadoc)
* @see de.dfki.km.augmentedtext.util.filter.AbstractFilter#filterEvent(de.dfki.km.augmentedtext.services.trackingdevices.TrackingEvent)
*/
@Override
public final EyeTrackingEvent filterEvent(final EyeTrackingEvent event) {
// Cap size
if (this.lastPoints.size() == this.backlogSize) {
this.lastPoints.remove(0);
}
this.lastPoints.add(event.getGazeCenter());
// Get point to return
final Point rval = getPoint();
// If nothing returned, return the event itself
if (rval == null) return event;
return new TrackingEventWrapper(event) {
@Override
public Point getGazeCenter() {
return (Point) rval.clone();
}
};
}
/**
* Return the central point to use.
*
* @return
*/
abstract Point getPoint();
/**
*
* @param newSize
*/
public void resize(int newSize) {
this.backlogSize = newSize;
}
}