001/* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2013, 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 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. 
025 * Other names may be trademarks of their respective owners.]
026 *
027 * --------------
028 * DialLayer.java
029 * --------------
030 * (C) Copyright 2006-2008, by Object Refinery Limited.
031 *
032 * Original Author:  David Gilbert (for Object Refinery Limited);
033 * Contributor(s):   -;
034 *
035 * Changes
036 * -------
037 * 03-Nov-2006 : Version 1 (DG);
038 *
039 */
040
041package org.jfree.chart.plot.dial;
042
043import java.awt.Graphics2D;
044import java.awt.geom.Rectangle2D;
045import java.io.Serializable;
046import java.util.EventListener;
047
048/**
049 * A dial layer draws itself within a reference frame.  The view frame is a
050 * subset of the reference frame, and defines the area that is actually
051 * visible.
052 * <br><br>
053 * Classes that implement this interface should be {@link Serializable},
054 * otherwise chart serialization may fail.
055 *
056 * @since 1.0.7
057 */
058public interface DialLayer {
059
060    /**
061     * Returns a flag that indicates whether or not the layer is visible.
062     *
063     * @return A boolean.
064     */
065    public boolean isVisible();
066
067    /**
068     * Registers a listener with this layer, so that it receives notification
069     * of changes to this layer.
070     *
071     * @param listener  the listener.
072     */
073    public void addChangeListener(DialLayerChangeListener listener);
074
075    /**
076     * Deregisters a listener, so that it no longer receives notification of
077     * changes to this layer.
078     *
079     * @param listener  the listener.
080     */
081    public void removeChangeListener(DialLayerChangeListener listener);
082
083    /**
084     * Returns <code>true</code> if the specified listener is currently
085     * registered with the this layer.
086     *
087     * @param listener  the listener.
088     *
089     * @return A boolean.
090     */
091    public boolean hasListener(EventListener listener);
092
093    /**
094     * Returns <code>true</code> if the drawing should be clipped to the
095     * dial window (which is defined by the {@link DialFrame}), and
096     * <code>false</code> otherwise.
097     *
098     * @return A boolean.
099     */
100    public boolean isClippedToWindow();
101
102    /**
103     * Draws the content of this layer.
104     *
105     * @param g2  the graphics target (<code>null</code> not permitted).
106     * @param plot  the plot (typically this should not be <code>null</code>,
107     *     but for a layer that doesn't need to reference the plot, it may
108     *     be permitted).
109     * @param frame  the reference frame for the dial's geometry
110     *     (<code>null</code> not permitted).  This is typically larger than
111     *     the visible area of the dial (see the next parameter).
112     * @param view  the visible area for the dial (<code>null</code> not
113     *     permitted).
114     */
115    public void draw(Graphics2D g2, DialPlot plot, Rectangle2D frame,
116            Rectangle2D view);
117
118}