001 /* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2009, by Object Refinery Limited and Contributors.
006 *
007 * Project Info: http://www.jfree.org/jfreechart/index.html
008 *
009 * This library is free software; you can redistribute it and/or modify it
010 * under the terms of the GNU Lesser General Public License as published by
011 * the Free Software Foundation; either version 2.1 of the License, or
012 * (at your option) any later version.
013 *
014 * This library is distributed in the hope that it will be useful, but
015 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
016 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
017 * License for more details.
018 *
019 * You should have received a copy of the GNU Lesser General Public
020 * License along with this library; if not, write to the Free Software
021 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
022 * USA.
023 *
024 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
025 * in the United States and other countries.]
026 *
027 * ------------
028 * Overlay.java
029 * ------------
030 * (C) Copyright 2009, by Object Refinery Limited.
031 *
032 * Original Author: David Gilbert (for Object Refinery Limited);
033 * Contributor(s): -;
034 *
035 * Changes:
036 * --------
037 * 09-Apr-2009 : Version 1 (DG);
038 *
039 */
040 package org.jfree.chart.panel;
041
042 import java.awt.Graphics2D;
043 import org.jfree.chart.ChartPanel;
044 import org.jfree.chart.event.OverlayChangeListener;
045
046 /**
047 * Defines the interface for an overlay that can be added to a
048 * {@link ChartPanel}.
049 *
050 * @since 1.0.13
051 */
052 public interface Overlay {
053
054 /**
055 * Paints the crosshairs in the layer.
056 *
057 * @param g2 the graphics target.
058 * @param chartPanel the chart panel.
059 */
060 public void paintOverlay(Graphics2D g2, ChartPanel chartPanel);
061
062 /**
063 * Registers a change listener with the overlay.
064 *
065 * @param listener the listener.
066 */
067 public void addChangeListener(OverlayChangeListener listener);
068
069 /**
070 * Deregisters a listener from the overlay.
071 *
072 * @param listener the listener.
073 */
074 public void removeChangeListener(OverlayChangeListener listener);
075
076 }