001/* ===========================================================
002 * Orson Charts : a 3D chart library for the Java(tm) platform
003 * ===========================================================
004 * 
005 * (C)opyright 2013-2022, by David Gilbert.  All rights reserved.
006 * 
007 * https://github.com/jfree/orson-charts
008 * 
009 * This program is free software: you can redistribute it and/or modify
010 * it under the terms of the GNU General Public License as published by
011 * the Free Software Foundation, either version 3 of the License, or
012 * (at your option) any later version.
013 *
014 * This program is distributed in the hope that it will be useful,
015 * but WITHOUT ANY WARRANTY; without even the implied warranty of
016 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
017 * GNU General Public License for more details.
018 *
019 * You should have received a copy of the GNU General Public License
020 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
021 * 
022 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. 
023 * Other names may be trademarks of their respective owners.]
024 * 
025 * If you do not wish to be bound by the terms of the GPL, an alternative
026 * commercial license can be purchased.  For details, please see visit the
027 * Orson Charts home page:
028 * 
029 * http://www.object-refinery.com/orsoncharts/index.html
030 * 
031 */
032
033package org.jfree.chart3d.legend;
034
035import org.jfree.chart3d.Chart3D;
036import org.jfree.chart3d.Orientation;
037import org.jfree.chart3d.graphics2d.Anchor2D;
038import org.jfree.chart3d.plot.Plot3D;
039import org.jfree.chart3d.style.ChartStyle;
040import org.jfree.chart3d.table.TableElement;
041
042/**
043 * A legend builder is responsible for creating a legend for a chart.  The API
044 * has been kept to a minimum intentionally, so as not to overly constrain 
045 * developers that want to implement a custom legend builder.  The 
046 * {@code get/setItemFont()} methods have been added for convenience
047 * because changing the font of the legend item text is a very common 
048 * operation.
049 * <p>
050 * Classes that implement this interface should also implement 
051 * {@code java.io.Serializable} if you intend to serialize and deserialize 
052 * chart objects.
053 * 
054 * @see Chart3D#setLegendBuilder(LegendBuilder) 
055 */
056public interface LegendBuilder {
057
058    /**
059     * Creates a legend for the specified plot.  If this method returns 
060     * {@code null}, no legend will be displayed.
061     * 
062     * @param plot  the plot ({@code null} not permitted).
063     * @param anchor  the anchor ({@code null} not permitted).
064     * @param orientation  the legend orientation ({@code null} not 
065     *         permitted).
066     * @param style  the style ({@code null} not permitted).
067     * 
068     * @return A legend (possibly {@code null}).
069     * 
070     * @since 1.2
071     */
072    TableElement createLegend(Plot3D plot, Anchor2D anchor, 
073            Orientation orientation, ChartStyle style);
074
075}