001/* ================================================
002 * JFreeChart-FX : JavaFX extensions for JFreeChart
003 * ================================================
004 *
005 * (C) Copyright 2017-2021, 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 * ScrollHandlerFX.java
029 * --------------------
030 * (C) Copyright 2014-2021, 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 java.awt.geom.Point2D;
040import javafx.scene.input.ScrollEvent;
041import org.jfree.chart.ChartRenderingInfo;
042import org.jfree.chart.JFreeChart;
043import org.jfree.chart.fx.ChartCanvas;
044import org.jfree.chart.plot.PiePlot;
045import org.jfree.chart.plot.Plot;
046import org.jfree.chart.plot.PlotRenderingInfo;
047import org.jfree.chart.plot.Zoomable;
048
049/**
050 * Handles scroll events (mouse wheel etc) on a {@link ChartCanvas}.
051 */
052public class ScrollHandlerFX extends AbstractMouseHandlerFX 
053        implements MouseHandlerFX {
054
055    /** The zoom factor. */
056    private double zoomFactor = 0.1;
057    
058    /**
059     * Creates a new instance with the specified ID.
060     * 
061     * @param id  the handler ID ({@code null} not permitted).
062     */
063    public ScrollHandlerFX(String id) {
064        super(id, false, false, false, false);
065        this.zoomFactor = 0.1;
066    };
067
068    /**
069     * Returns the zoom factor.  The default value is 0.10 (ten percent).
070     * 
071     * @return The zoom factor. 
072     */
073    public double getZoomFactor() {
074        return this.zoomFactor;
075    }
076
077    /**
078     * Sets the zoom factor (a percentage amount by which the mouse wheel 
079     * movement will change the chart size).
080     * 
081     * @param zoomFactor  the zoom factor.
082     */
083    public void setZoomFactor(double zoomFactor) {
084        this.zoomFactor = zoomFactor;
085    }
086    
087    @Override
088    public void handleScroll(ChartCanvas canvas, ScrollEvent e) {
089        JFreeChart chart = canvas.getChart();
090        if (chart == null) {
091            return;
092        }
093        Plot plot = chart.getPlot();
094        if (plot instanceof Zoomable) {
095            Zoomable zoomable = (Zoomable) plot;
096            handleZoomable(canvas, zoomable, e);
097        }
098        else if (plot instanceof PiePlot) {
099            PiePlot pp = (PiePlot) plot;
100            pp.handleMouseWheelRotation((int) e.getDeltaY());
101        }
102    }
103    
104    /**
105     * Handle the case where a plot implements the {@link Zoomable} interface.
106     *
107     * @param canvas  the chart canvas.
108     * @param zoomable  the zoomable plot.
109     * @param e  the mouse wheel event.
110     */
111    private void handleZoomable(ChartCanvas canvas, Zoomable zoomable, 
112            ScrollEvent e) {
113        if (canvas.getChart() == null) {
114            return;
115        }
116        // don't zoom unless the mouse pointer is in the plot's data area
117        ChartRenderingInfo info = canvas.getRenderingInfo();
118        PlotRenderingInfo pinfo = info.getPlotInfo();
119        Point2D p = new Point2D.Double(e.getX(), e.getY());
120        if (pinfo.getDataArea().contains(p)) {
121            Plot plot = (Plot) zoomable;
122            // do not notify while zooming each axis
123            boolean notifyState = plot.isNotify();
124            plot.setNotify(false);
125            int clicks = (int) e.getDeltaY();
126            double zf = 1.0 + this.zoomFactor;
127            if (clicks < 0) {
128                zf = 1.0 / zf;
129            }
130            if (canvas.isDomainZoomable()) {
131                zoomable.zoomDomainAxes(zf, pinfo, p, true);
132            }
133            if (canvas.isRangeZoomable()) {
134                zoomable.zoomRangeAxes(zf, pinfo, p, true);
135            }
136            plot.setNotify(notifyState);  // this generates the change event too
137        } 
138    }
139
140}