001/* ===========================================================
002 * JFreeChart : a free chart library for the Java(tm) platform
003 * ===========================================================
004 *
005 * (C) Copyright 2000-2007, 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 * DialScale.java
029 * --------------
030 * (C) Copyright 2006-2007, 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 * 17-Oct-2007 : Made this an extension of the DialLayer interface (DG);
039 * 
040 */
041
042package org.jfree.chart.plot.dial;
043
044/**
045 * A dial scale is a specialised layer that has the ability to convert data 
046 * values into angles.
047 */
048public interface DialScale extends DialLayer {
049    
050    /**
051     * Converts a data value to an angle (in degrees, using the same 
052     * specification as Java's Arc2D class).
053     *
054     * @param value  the data value.
055     *
056     * @return The angle in degrees.
057     * 
058     * @see #angleToValue(double)
059     */
060    public double valueToAngle(double value);
061    
062    /**
063     * Converts an angle (in degrees) to a data value.
064     *
065     * @param angle  the angle (in degrees).
066     *
067     * @return The data value.
068     * 
069     * @see #valueToAngle(double)
070     */
071    public double angleToValue(double angle);
072    
073}