
jfreechart example source code file (CrosshairState.java)
The jfreechart CrosshairState.java source code/* =========================================================== * JFreeChart : a free chart library for the Java(tm) platform * =========================================================== * * (C) Copyright 20002008, by Object Refinery Limited and Contributors. * * Project Info: http://www.jfree.org/jfreechart/index.html * * This library is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation; either version 2.1 of the License, or * (at your option) any later version. * * This library is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public * License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 021101301, * USA. * * [Java is a trademark or registered trademark of Sun Microsystems, Inc. * in the United States and other countries.] * *  * CrosshairState.java *  * (C) Copyright 20022008, by Object Refinery Limited. * * Original Author: David Gilbert (for Object Refinery Limited); * Contributor(s): ; * * Changes *  * 24Jan2002 : Version 1 (DG); * 05Mar2002 : Added Javadoc comments (DG); * 26Sep2002 : Fixed errors reported by Checkstyle (DG); * 19Sep2003 : Modified crosshair distance calculation (DG); * 04Dec2003 : Crosshair anchor point now stored outside chart since it is * dependent on the display target (DG); * 25Feb2004 : Replaced CrosshairInfo > CrosshairState (DG); *  JFREECHART 1.0.x  * 13Oct2006 : Fixed initialisation of CrosshairState  see bug report * 1565168 (DG); * 06Feb2007 : Added new fields and methods to fix bug 1086307 (DG); * 26Jun2008 : Now tracks dataset index (DG); * */ package org.jfree.chart.plot; import java.awt.geom.Point2D; /** * Maintains state information about crosshairs on a plot between successive * calls to the renderer's draw method. This class is used internally by * JFreeChart  it is not intended for external use. */ public class CrosshairState { /** * A flag that controls whether the distance is calculated in data space * or Java2D space. */ private boolean calculateDistanceInDataSpace = false; /** The xvalue (in data space) for the anchor point. */ private double anchorX; /** The yvalue (in data space) for the anchor point. */ private double anchorY; /** The anchor point in Java2D space  if null, don't update crosshair. */ private Point2D anchor; /** The xvalue for the current crosshair point. */ private double crosshairX; /** The yvalue for the current crosshair point. */ private double crosshairY; /** * The dataset index that the crosshair point relates to (this determines * the axes that the crosshairs will be plotted against). * * @since 1.0.11 */ private int datasetIndex; /** * The index of the domain axis that the crosshair xvalue is measured * against. * * @since 1.0.4 */ private int domainAxisIndex; /** * The index of the range axis that the crosshair yvalue is measured * against. * * @since 1.0.4 */ private int rangeAxisIndex; /** * The smallest distance (so far) between the anchor point and a data * point. */ private double distance; /** * Creates a new <code>CrosshairState instance that calculates * distance in Java2D space. */ public CrosshairState() { this(false); } /** * Creates a new <code>CrosshairState instance. * * @param calculateDistanceInDataSpace a flag that controls whether the * distance is calculated in data * space or Java2D space. */ public CrosshairState(boolean calculateDistanceInDataSpace) { this.calculateDistanceInDataSpace = calculateDistanceInDataSpace; } /** * Returns the distance between the anchor point and the current crosshair * point. * * @return The distance. * * @see #setCrosshairDistance(double) * @since 1.0.3 */ public double getCrosshairDistance() { return this.distance; } /** * Sets the distance between the anchor point and the current crosshair * point. As each data point is processed, its distance to the anchor * point is compared with this value and, if it is closer, the data point * becomes the new crosshair point. * * @param distance the distance. * * @see #getCrosshairDistance() */ public void setCrosshairDistance(double distance) { this.distance = distance; } /** * Evaluates a data point and if it is the closest to the anchor point it * becomes the new crosshair point. * <P> * To understand this method, you need to know the context in which it will * be called. An instance of this class is passed to an * {@link org.jfree.chart.renderer.xy.XYItemRenderer} as * each data point is plotted. As the point is plotted, it is passed to * this method to see if it should be the new crosshair point. * * @param x x coordinate (measured against the domain axis). * @param y y coordinate (measured against the range axis). * @param transX x translated into Java2D space. * @param transY y translated into Java2D space. * @param orientation the plot orientation. * * @deprecated Use {@link #updateCrosshairPoint(double, double, int, int, * double, double, PlotOrientation)}. See bug report 1086307. */ public void updateCrosshairPoint(double x, double y, double transX, double transY, PlotOrientation orientation) { updateCrosshairPoint(x, y, 0, 0, transX, transY, orientation); } /** * Evaluates a data point and if it is the closest to the anchor point it * becomes the new crosshair point. * <P> * To understand this method, you need to know the context in which it will * be called. An instance of this class is passed to an * {@link org.jfree.chart.renderer.xy.XYItemRenderer} as * each data point is plotted. As the point is plotted, it is passed to * this method to see if it should be the new crosshair point. * * @param x x coordinate (measured against the domain axis). * @param y y coordinate (measured against the range axis). * @param domainAxisIndex the index of the domain axis for this point. * @param rangeAxisIndex the index of the range axis for this point. * @param transX x translated into Java2D space. * @param transY y translated into Java2D space. * @param orientation the plot orientation. * * @since 1.0.4 */ public void updateCrosshairPoint(double x, double y, int domainAxisIndex, int rangeAxisIndex, double transX, double transY, PlotOrientation orientation) { if (this.anchor != null) { double d = 0.0; if (this.calculateDistanceInDataSpace) { d = (x  this.anchorX) * (x  this.anchorX) + (y  this.anchorY) * (y  this.anchorY); } else { double xx = this.anchor.getX(); double yy = this.anchor.getY(); if (orientation == PlotOrientation.HORIZONTAL) { double temp = yy; yy = xx; xx = temp; } d = (transX  xx) * (transX  xx) + (transY  yy) * (transY  yy); } if (d < this.distance) { this.crosshairX = x; this.crosshairY = y; this.domainAxisIndex = domainAxisIndex; this.rangeAxisIndex = rangeAxisIndex; this.distance = d; } } } /** * Evaluates an xvalue and if it is the closest to the anchor xvalue it * becomes the new crosshair value. * <P> * Used in cases where only the xaxis is numerical. * * @param candidateX x position of the candidate for the new crosshair * point. * * @deprecated Use {@link #updateCrosshairX(double, int)}. See bug report * 1086307. */ public void updateCrosshairX(double candidateX) { updateCrosshairX(candidateX, 0); } /** * Evaluates an xvalue and if it is the closest to the anchor xvalue it * becomes the new crosshair value. * <P> * Used in cases where only the xaxis is numerical. * * @param candidateX x position of the candidate for the new crosshair * point. * @param domainAxisIndex the index of the domain axis for this xvalue. * * @since 1.0.4 */ public void updateCrosshairX(double candidateX, int domainAxisIndex) { double d = Math.abs(candidateX  this.anchorX); if (d < this.distance) { this.crosshairX = candidateX; this.domainAxisIndex = domainAxisIndex; this.distance = d; } } /** * Evaluates a yvalue and if it is the closest to the anchor yvalue it * becomes the new crosshair value. * <P> * Used in cases where only the yaxis is numerical. * * @param candidateY y position of the candidate for the new crosshair * point. * * @deprecated Use {@link #updateCrosshairY(double, int)}. See bug report * 1086307. */ public void updateCrosshairY(double candidateY) { updateCrosshairY(candidateY, 0); } /** * Evaluates a yvalue and if it is the closest to the anchor yvalue it * becomes the new crosshair value. * <P> * Used in cases where only the yaxis is numerical. * * @param candidateY y position of the candidate for the new crosshair * point. * @param rangeAxisIndex the index of the range axis for this yvalue. * * @since 1.0.4 */ public void updateCrosshairY(double candidateY, int rangeAxisIndex) { double d = Math.abs(candidateY  this.anchorY); if (d < this.distance) { this.crosshairY = candidateY; this.rangeAxisIndex = rangeAxisIndex; this.distance = d; } } /** * Returns the anchor point. * * @return The anchor point. * * @see #setAnchor(Point2D) * * @since 1.0.3 */ public Point2D getAnchor() { return this.anchor; } /** * Sets the anchor point. This is usually the mouse click point in a chart * panel, and the crosshair point will often be the data item that is * closest to the anchor point. * <br> Other jfreechart examples (source code examples)Here is a short list of links related to this jfreechart CrosshairState.java source code file: 
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