001/* ================================================
002 * JFreeChart-FX : JavaFX extensions for JFreeChart
003 * ================================================
004 *
005 * (C) Copyright 2017, by Object Refinery Limited and Contributors.
006 *
007 * Project Info:  https://github.com/jfree/jfreechart-fx
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 * TooltipHandlerFX.java
029 * ---------------------
030 * (C) Copyright 2014, by Object Refinery Limited and Contributors.
031 *
032 * Original Author:  David Gilbert (for Object Refinery Limited);
033 * Contributor(s):   -;
034 *
035 */
036
037package org.jfree.chart.fx.interaction;
038
039import javafx.scene.input.MouseEvent;
040import org.jfree.chart.ChartRenderingInfo;
041import org.jfree.chart.entity.ChartEntity;
042import org.jfree.chart.entity.EntityCollection;
043import org.jfree.chart.fx.ChartCanvas;
044
045/**
046 * Handles the updating of tooltips on a {@link ChartCanvas}.
047 */
048public class TooltipHandlerFX extends AbstractMouseHandlerFX 
049        implements MouseHandlerFX {
050    
051    /**
052     * Creates a new instance with the specified ID.
053     * 
054     * @param id  the handler id ({@code null} not permitted).
055     */
056    public TooltipHandlerFX(String id) {
057        super(id, false, false, false, false);
058    }
059
060    /**
061     * Handles a mouse moved event by updating the tooltip.
062     * 
063     * @param canvas  the chart canvas ({@code null} not permitted).
064     * @param e  the mouse event.
065     */
066    @Override
067    public void handleMouseMoved(ChartCanvas canvas, MouseEvent e) {
068        if (!canvas.isTooltipEnabled()) {
069            return;
070        }
071        String text = getTooltipText(canvas, e.getX(), e.getY());
072        canvas.setTooltip(text, e.getScreenX(), e.getScreenY());
073    }
074    
075    /**
076     * Returns the tooltip text.
077     * 
078     * @param canvas  the canvas that is displaying the chart.
079     * @param x  the x-coordinate of the mouse pointer.
080     * @param y  the y-coordinate of the mouse pointer.
081     * 
082     * @return String The tooltip text (possibly {@code null}).
083      */
084    private String getTooltipText(ChartCanvas canvas, double x, double y) {
085        ChartRenderingInfo info = canvas.getRenderingInfo();
086        if (info == null) {
087            return null;
088        }
089        EntityCollection entities = info.getEntityCollection();
090        if (entities == null) {
091            return null;
092        }
093        ChartEntity entity = entities.getEntity(x, y);
094        if (entity == null) {
095            return null;
096        }
097        return entity.getToolTipText();
098    }
099    
100}