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 * AnchorHandlerFX.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.MouseEvent;
041import org.jfree.chart.fx.ChartCanvas;
042
043/**
044 * Handles mouse clicks on the {@link ChartCanvas} by updating the anchor and 
045 * redrawing the chart.
046 */
047public class AnchorHandlerFX extends AbstractMouseHandlerFX {
048    
049    /** Records the mouse down location. */
050    private Point2D mousePressedPoint;
051    
052    /**
053     * Creates a new instance.
054     * 
055     * @param id  the id ({@code null} not permitted).
056     */
057    public AnchorHandlerFX(String id) {
058        super(id, false, false, false, false);
059    }
060    
061    /**
062     * Handles a mouse pressed event by recording the location of the mouse
063     * pointer (so that later we can check that the click isn't part of a
064     * drag).
065     * 
066     * @param canvas  the chart canvas.
067     * @param e  the mouse event.
068     */
069    @Override
070    public void handleMousePressed(ChartCanvas canvas, MouseEvent e) {
071        this.mousePressedPoint = new Point2D.Double(e.getX(), e.getY());
072    }
073
074    /**
075     * Handles a mouse clicked event by setting the anchor point for the
076     * canvas and redrawing the chart (the anchor point is a reference point
077     * used by the chart to determine crosshair lines).
078     * 
079     * @param canvas  the chart canvas ({@code null} not permitted).
080     * @param e  the mouse event ({@code null} not permitted).
081     */
082    @Override
083    public void handleMouseClicked(ChartCanvas canvas, MouseEvent e) {
084        if (this.mousePressedPoint == null) {
085            return;
086        }
087        Point2D currPt = new Point2D.Double(e.getX(), e.getY());
088        if (this.mousePressedPoint.distance(currPt) < 2) {
089            canvas.setAnchor(currPt);
090        }
091        this.mousePressedPoint = null;
092    }
093    
094}
095