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     * ShadowGenerator.java
029     * --------------------
030     * (C) Copyright 2009, 2011, by Object Refinery Limited and Contributors.
031     *
032     * Original Author:  David Gilbert (for Object Refinery Limited);
033     * Contributor(s):   -;
034     *
035     * Changes:
036     * --------
037     * 10-Jul-2009 : Version 1 (DG);
038     *
039     */
040    
041    package org.jfree.chart.util;
042    
043    import java.awt.image.BufferedImage;
044    
045    /**
046     * An interface that defines the API for a shadow generator.  Some plot
047     * classes use this to create drop shadows.
048     *
049     * @since 1.0.14
050     */
051    public interface ShadowGenerator {
052    
053        /**
054         * Creates and returns an image containing the drop shadow for the
055         * specified source image.
056         *
057         * @param source  the source image.
058         *
059         * @return A new image containing the shadow.
060         */
061        public BufferedImage createDropShadow(BufferedImage source);
062    
063        /**
064         * Calculates the x-offset for drawing the shadow image relative to the
065         * source.
066         *
067         * @return The x-offset.
068         */
069        public int calculateOffsetX();
070    
071        /**
072         * Calculates the y-offset for drawing the shadow image relative to the
073         * source.
074         *
075         * @return The y-offset.
076         */
077        public int calculateOffsetY();
078    
079    }