CrosshairState.java
/* ===========================================================
* JFreeChart : a free chart library for the Java(tm) platform
* ===========================================================
*
* (C) Copyright 2000-2022, by David Gilbert 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 02110-1301,
* USA.
*
* [Oracle and Java are registered trademarks of Oracle and/or its affiliates.
* Other names may be trademarks of their respective owners.]
*
* -------------------
* CrosshairState.java
* -------------------
* (C) Copyright 2002-2022, by David Gilbert.
*
* Original Author: David Gilbert;
* Contributor(s): -;
*
*/
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 x-value (in data space) for the anchor point. */
private double anchorX;
/** The y-value (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 x-value for the current crosshair point. */
private double crosshairX;
/** The y-value 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).
*/
private int datasetIndex;
/**
* 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. Determination of the
* data point nearest the anchor point can be calculated in either
* dataspace or Java2D space. The former should only be used for charts
* with a single set of axes.
*
* @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)
*/
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;
}
/**
* Updates the crosshair point.
*
* @param x the x-value.
* @param y the y-value.
* @param datasetIndex the dataset index.
* @param transX the x-value in Java2D space.
* @param transY the y-value in Java2D space.
* @param orientation the plot orientation ({@code null} not permitted).
*/
public void updateCrosshairPoint(double x, double y, int datasetIndex,
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 {
// anchor point is in Java2D coordinates
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.datasetIndex = datasetIndex;
this.distance = d;
}
}
}
/**
* Checks to see if the specified data point is the closest to the
* anchor point and, if yes, updates the current state.
*
* @param x the x-value.
* @param transX the x-value in Java2D space.
* @param datasetIndex the dataset index.
*/
public void updateCrosshairX(double x, double transX, int datasetIndex) {
if (this.anchor == null) {
return;
}
double d = Math.abs(transX - this.anchor.getX());
if (d < this.distance) {
this.crosshairX = x;
this.datasetIndex = datasetIndex;
this.distance = d;
}
}
/**
* Evaluates a y-value and if it is the closest to the anchor y-value it
* becomes the new crosshair value.
* <P>
* Used in cases where only the y-axis is numerical.
*
* @param candidateY y position of the candidate for the new crosshair
* point.
* @param transY the y-value in Java2D space.
* @param datasetIndex the index of the range axis for this y-value.
*/
public void updateCrosshairY(double candidateY, double transY, int datasetIndex) {
if (this.anchor == null) {
return;
}
double d = Math.abs(transY - this.anchor.getY());
if (d < this.distance) {
this.crosshairY = candidateY;
this.datasetIndex = datasetIndex;
this.distance = d;
}
}
/**
* Returns the anchor point.
*
* @return The anchor point.
*
* @see #setAnchor(Point2D)
*/
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><br>
* Note that the x and y coordinates (in data space) are not updated by
* this method - the caller is responsible for ensuring that this happens
* in sync.
*
* @param anchor the anchor point ({@code null} permitted).
*
* @see #getAnchor()
*/
public void setAnchor(Point2D anchor) {
this.anchor = anchor;
}
/**
* Returns the x-coordinate (in data space) for the anchor point.
*
* @return The x-coordinate of the anchor point.
*/
public double getAnchorX() {
return this.anchorX;
}
/**
* Sets the x-coordinate (in data space) for the anchor point. Note that
* this does NOT update the anchor itself - the caller is responsible for
* ensuring this is done in sync.
*
* @param x the x-coordinate.
*/
public void setAnchorX(double x) {
this.anchorX = x;
}
/**
* Returns the y-coordinate (in data space) for the anchor point.
*
* @return The y-coordinate of teh anchor point.
*/
public double getAnchorY() {
return this.anchorY;
}
/**
* Sets the y-coordinate (in data space) for the anchor point. Note that
* this does NOT update the anchor itself - the caller is responsible for
* ensuring this is done in sync.
*
* @param y the y-coordinate.
*/
public void setAnchorY(double y) {
this.anchorY = y;
}
/**
* Get the x-value for the crosshair point.
*
* @return The x position of the crosshair point.
*
* @see #setCrosshairX(double)
*/
public double getCrosshairX() {
return this.crosshairX;
}
/**
* Sets the x coordinate for the crosshair. This is the coordinate in data
* space measured against the domain axis.
*
* @param x the coordinate.
*
* @see #getCrosshairX()
* @see #setCrosshairY(double)
* @see #updateCrosshairPoint(double, double, int, double, double,
* PlotOrientation)
*/
public void setCrosshairX(double x) {
this.crosshairX = x;
}
/**
* Get the y-value for the crosshair point. This is the coordinate in data
* space measured against the range axis.
*
* @return The y position of the crosshair point.
*
* @see #setCrosshairY(double)
*/
public double getCrosshairY() {
return this.crosshairY;
}
/**
* Sets the y coordinate for the crosshair.
*
* @param y the y coordinate.
*
* @see #getCrosshairY()
* @see #setCrosshairX(double)
* @see #updateCrosshairPoint(double, double, int, double, double,
* PlotOrientation)
*/
public void setCrosshairY(double y) {
this.crosshairY = y;
}
/**
* Returns the dataset index that the crosshair values relate to. The
* dataset is mapped to specific axes, and this is how the crosshairs are
* mapped also.
*
* @return The dataset index.
*
* @see #setDatasetIndex(int)
*/
public int getDatasetIndex() {
return this.datasetIndex;
}
/**
* Sets the dataset index that the current crosshair values relate to.
*
* @param index the dataset index.
*
* @see #getDatasetIndex()
*/
public void setDatasetIndex(int index) {
this.datasetIndex = index;
}
}