jfreechart example source code file (ModuloAxis.java)

This example jfreechart source code file (ModuloAxis.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - jfreechart tags/keywords

awt, axischangeevent, geometry, moduloaxis, moduloaxis, numberaxis, range, range, rectangle2d, rectangle2d, rectangleedge, rectangleedge

The jfreechart ModuloAxis.java source code

/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2008, 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  02110-1301,
 * USA.
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
 * in the United States and other countries.]
 *
 * ---------------
 * ModuloAxis.java
 * ---------------
 * (C) Copyright 2004-2008, by Object Refinery Limited.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   -;
 *
 * Changes
 * -------
 * 13-Aug-2004 : Version 1 (DG);
 * 13-Nov-2007 : Implemented equals() (DG);
 *
 */

package org.jfree.chart.axis;

import java.awt.geom.Rectangle2D;

import org.jfree.chart.event.AxisChangeEvent;
import org.jfree.data.Range;
import org.jfree.ui.RectangleEdge;

/**
 * An axis that displays numerical values within a fixed range using a modulo
 * calculation.
 */
public class ModuloAxis extends NumberAxis {

    /**
     * The fixed range for the axis - all data values will be mapped to this
     * range using a modulo calculation.
     */
    private Range fixedRange;

    /**
     * The display start value (this will sometimes be > displayEnd, in which
     * case the axis wraps around at some point in the middle of the axis).
     */
    private double displayStart;

    /**
     * The display end value.
     */
    private double displayEnd;

    /**
     * Creates a new axis.
     *
     * @param label  the axis label (<code>null permitted).
     * @param fixedRange  the fixed range (<code>null not permitted).
     */
    public ModuloAxis(String label, Range fixedRange) {
        super(label);
        this.fixedRange = fixedRange;
        this.displayStart = 270.0;
        this.displayEnd = 90.0;
    }

    /**
     * Returns the display start value.
     *
     * @return The display start value.
     */
    public double getDisplayStart() {
        return this.displayStart;
    }

    /**
     * Returns the display end value.
     *
     * @return The display end value.
     */
    public double getDisplayEnd() {
        return this.displayEnd;
    }

    /**
     * Sets the display range.  The values will be mapped to the fixed range if
     * necessary.
     *
     * @param start  the start value.
     * @param end  the end value.
     */
    public void setDisplayRange(double start, double end) {
        this.displayStart = mapValueToFixedRange(start);
        this.displayEnd = mapValueToFixedRange(end);
        if (this.displayStart < this.displayEnd) {
            setRange(this.displayStart, this.displayEnd);
        }
        else {
            setRange(this.displayStart, this.fixedRange.getUpperBound()
                  + (this.displayEnd - this.fixedRange.getLowerBound()));
        }
        notifyListeners(new AxisChangeEvent(this));
    }

    /**
     * This method should calculate a range that will show all the data values.
     * For now, it just sets the axis range to the fixedRange.
     */
    protected void autoAdjustRange() {
        setRange(this.fixedRange, false, false);
    }

    /**
     * Translates a data value to a Java2D coordinate.
     *
     * @param value  the value.
     * @param area  the area.
     * @param edge  the edge.
     *
     * @return A Java2D coordinate.
     */
    public double valueToJava2D(double value, Rectangle2D area,
                                RectangleEdge edge) {
        double result = 0.0;
        double v = mapValueToFixedRange(value);
        if (this.displayStart < this.displayEnd) {  // regular number axis
            result = trans(v, area, edge);
        }
        else {  // displayStart > displayEnd, need to handle split
            double cutoff = (this.displayStart + this.displayEnd) / 2.0;
            double length1 = this.fixedRange.getUpperBound()
                             - this.displayStart;
            double length2 = this.displayEnd - this.fixedRange.getLowerBound();
            if (v > cutoff) {
                result = transStart(v, area, edge, length1, length2);
            }
            else {
                result = transEnd(v, area, edge, length1, length2);
            }
        }
        return result;
    }

    /**
     * A regular translation from a data value to a Java2D value.
     *
     * @param value  the value.
     * @param area  the data area.
     * @param edge  the edge along which the axis lies.
     *
     * @return The Java2D coordinate.
     */
    private double trans(double value, Rectangle2D area, RectangleEdge edge) {
        double min = 0.0;
        double max = 0.0;
        if (RectangleEdge.isTopOrBottom(edge)) {
            min = area.getX();
            max = area.getX() + area.getWidth();
        }
        else if (RectangleEdge.isLeftOrRight(edge)) {
            min = area.getMaxY();
            max = area.getMaxY() - area.getHeight();
        }
        if (isInverted()) {
            return max - ((value - this.displayStart)
                   / (this.displayEnd - this.displayStart)) * (max - min);
        }
        else {
            return min + ((value - this.displayStart)
                   / (this.displayEnd - this.displayStart)) * (max - min);
        }

    }

    /**
     * Translates a data value to a Java2D value for the first section of the
     * axis.
     *
     * @param value  the value.
     * @param area  the data area.
     * @param edge  the edge along which the axis lies.
     * @param length1  the length of the first section.
     * @param length2  the length of the second section.
     *
     * @return The Java2D coordinate.
     */
    private double transStart(double value, Rectangle2D area,
                              RectangleEdge edge,
                              double length1, double length2) {
        double min = 0.0;
        double max = 0.0;
        if (RectangleEdge.isTopOrBottom(edge)) {
            min = area.getX();
            max = area.getX() + area.getWidth() * length1 / (length1 + length2);
        }
        else if (RectangleEdge.isLeftOrRight(edge)) {
            min = area.getMaxY();
            max = area.getMaxY() - area.getHeight() * length1
                  / (length1 + length2);
        }
        if (isInverted()) {
            return max - ((value - this.displayStart)
                / (this.fixedRange.getUpperBound() - this.displayStart))
                * (max - min);
        }
        else {
            return min + ((value - this.displayStart)
                / (this.fixedRange.getUpperBound() - this.displayStart))
                * (max - min);
        }

    }

    /**
     * Translates a data value to a Java2D value for the second section of the
     * axis.
     *
     * @param value  the value.
     * @param area  the data area.
     * @param edge  the edge along which the axis lies.
     * @param length1  the length of the first section.
     * @param length2  the length of the second section.
     *
     * @return The Java2D coordinate.
     */
    private double transEnd(double value, Rectangle2D area, RectangleEdge edge,
                            double length1, double length2) {
        double min = 0.0;
        double max = 0.0;
        if (RectangleEdge.isTopOrBottom(edge)) {
            max = area.getMaxX();
            min = area.getMaxX() - area.getWidth() * length2
                  / (length1 + length2);
        }
        else if (RectangleEdge.isLeftOrRight(edge)) {
            max = area.getMinY();
            min = area.getMinY() + area.getHeight() * length2
                  / (length1 + length2);
        }
        if (isInverted()) {
            return max - ((value - this.fixedRange.getLowerBound())
                    / (this.displayEnd - this.fixedRange.getLowerBound()))
                    * (max - min);
        }
        else {
            return min + ((value - this.fixedRange.getLowerBound())
                    / (this.displayEnd - this.fixedRange.getLowerBound()))
                    * (max - min);
        }

    }

    /**
     * Maps a data value into the fixed range.
     *
     * @param value  the value.
     *
     * @return The mapped value.
     */
    private double mapValueToFixedRange(double value) {
        double lower = this.fixedRange.getLowerBound();
        double length = this.fixedRange.getLength();
        if (value < lower) {
            return lower + length + ((value - lower) % length);
        }
        else {
            return lower + ((value - lower) % length);
        }
    }

    /**
     * Translates a Java2D coordinate into a data value.
     *
     * @param java2DValue  the Java2D coordinate.
     * @param area  the area.
     * @param edge  the edge.
     *
     * @return The Java2D coordinate.
     */
    public double java2DToValue(double java2DValue, Rectangle2D area,
                                RectangleEdge edge) {
        double result = 0.0;
        if (this.displayStart < this.displayEnd) {  // regular number axis
            result = super.java2DToValue(java2DValue, area, edge);
        }
        else {  // displayStart > displayEnd, need to handle split

        }
        return result;
    }

    /**
     * Returns the display length for the axis.
     *
     * @return The display length.
     */
    private double getDisplayLength() {
        if (this.displayStart < this.displayEnd) {
            return (this.displayEnd - this.displayStart);
        }
        else {
            return (this.fixedRange.getUpperBound() - this.displayStart)
                + (this.displayEnd - this.fixedRange.getLowerBound());
        }
    }

    /**
     * Returns the central value of the current display range.
     *
     * @return The central value.
     */
    private double getDisplayCentralValue() {
        return mapValueToFixedRange(
            this.displayStart + (getDisplayLength() / 2)
        );
    }

    /**
     * Increases or decreases the axis range by the specified percentage about
     * the central value and sends an {@link AxisChangeEvent} to all registered
     * listeners.
     * <P>
     * To double the length of the axis range, use 200% (2.0).
     * To halve the length of the axis range, use 50% (0.5).
     *
     * @param percent  the resize factor.
     */
    public void resizeRange(double percent) {
        resizeRange(percent, getDisplayCentralValue());
    }

    /**
     * Increases or decreases the axis range by the specified percentage about
     * the specified anchor value and sends an {@link AxisChangeEvent} to all
     * registered listeners.
     * <P>
     * To double the length of the axis range, use 200% (2.0).
     * To halve the length of the axis range, use 50% (0.5).
     *
     * @param percent  the resize factor.
     * @param anchorValue  the new central value after the resize.
     */
    public void resizeRange(double percent, double anchorValue) {

        if (percent > 0.0) {
            double halfLength = getDisplayLength() * percent / 2;
            setDisplayRange(anchorValue - halfLength, anchorValue + halfLength);
        }
        else {
            setAutoRange(true);
        }

    }

    /**
     * Converts a length in data coordinates into the corresponding length in
     * Java2D coordinates.
     *
     * @param length  the length.
     * @param area  the plot area.
     * @param edge  the edge along which the axis lies.
     *
     * @return The length in Java2D coordinates.
     */
    public double lengthToJava2D(double length, Rectangle2D area,
                                 RectangleEdge edge) {
        double axisLength = 0.0;
        if (this.displayEnd > this.displayStart) {
            axisLength = this.displayEnd - this.displayStart;
        }
        else {
            axisLength = (this.fixedRange.getUpperBound() - this.displayStart)
                + (this.displayEnd - this.fixedRange.getLowerBound());
        }
        double areaLength = 0.0;
        if (RectangleEdge.isLeftOrRight(edge)) {
            areaLength = area.getHeight();
        }
        else {
            areaLength = area.getWidth();
        }
        return (length / axisLength) * areaLength;
    }

    /**
     * Tests this axis for equality with an arbitrary object.
     *
     * @param obj  the object (<code>null permitted).
     *
     * @return A boolean.
     */
    public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        }
        if (!(obj instanceof ModuloAxis)) {
            return false;
        }
        ModuloAxis that = (ModuloAxis) obj;
        if (this.displayStart != that.displayStart) {
            return false;
        }
        if (this.displayEnd != that.displayEnd) {
            return false;
        }
        if (!this.fixedRange.equals(that.fixedRange)) {
            return false;
        }
        return super.equals(obj);
    }

}