    001/* ===========================================================
    002 * JFreeChart : a free chart library for the Java(tm) platform
    003 * ===========================================================
    004 *
    005 * (C) Copyright 2000-2011, 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}