arrowneedle.java

JfreeChart 常用图表例子

/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2005, 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
 * in the United States and other countries.]
 *
 * ----------------
 * ArrowNeedle.java
 * ----------------
 * (C) Copyright 2002-2005, by the Australian Antarctic Division and 
 *                          Contributors.
 *
 * Original Author:  Bryan Scott (for the Australian Antarctic Division);
 * Contributor(s):   David Gilbert (for Object Refinery Limited);
 *
 * $Id: ArrowNeedle.java,v 1.3 2005/05/19 15:42:54 mungady Exp $
 *
 * Changes:
 * --------
 * 25-Sep-2002 : Version 1, contributed by Bryan Scott (DG);
 * 27-Mar-2003 : Implemented Serializable (DG);
 * 09-Sep-2003 : Added equals() method (DG);
 *
 */

package org.jfree.chart.needle;

import java.awt.Graphics2D;
import java.awt.Shape;
import java.awt.geom.GeneralPath;
import java.awt.geom.Line2D;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import java.io.Serializable;

/**
 * A needle in the shape of an arrow.
 *
 * @author Bryan Scott
 */
public class ArrowNeedle extends MeterNeedle implements Serializable {

    /** For serialization. */
    private static final long serialVersionUID = -5334056511213782357L;
    
    /** 
     * A flag controlling whether or not there is an arrow at the top of the 
     * needle. 
     */
    private boolean isArrowAtTop = true;

    /**
     * Constructs a new arrow needle.
     *
     * @param isArrowAtTop  a flag that controls whether or not there is an 
     *                      arrow at the top of the needle.
     */
    public ArrowNeedle(boolean isArrowAtTop) {
        this.isArrowAtTop = isArrowAtTop;
    }

    /**
     * Draws the needle.
     *
     * @param g2  the graphics device.
     * @param plotArea  the plot area.
     * @param rotate  the rotation point.
     * @param angle  the angle.
     */
    protected void drawNeedle(Graphics2D g2, Rectangle2D plotArea, 
                              Point2D rotate, double angle) {

        Line2D shape = new Line2D.Float();
        Shape d = null;

        float x = (float) (plotArea.getMinX() +  (plotArea.getWidth() / 2));
        float minY = (float) plotArea.getMinY();
        float maxY = (float) plotArea.getMaxY();
        shape.setLine(x, minY, x, maxY);

        GeneralPath shape1 = new GeneralPath();
        if (this.isArrowAtTop) {
            shape1.moveTo(x, minY);
            minY += 4 * getSize();
        }
        else {
            shape1.moveTo(x, maxY);
            minY = maxY - 4 * getSize();
        }
        shape1.lineTo(x + getSize(), minY);
        shape1.lineTo(x - getSize(), minY);
        shape1.closePath();

        if ((rotate != null) && (angle != 0)) {
            getTransform().setToRotation(angle, rotate.getX(), rotate.getY());
            d = getTransform().createTransformedShape(shape);
        }
        else {
            d = shape;
        }
        defaultDisplay(g2, d);

        if ((rotate != null) && (angle != 0)) {
            d = getTransform().createTransformedShape(shape1);
        }
        else {
            d = shape1;
        }
        defaultDisplay(g2, d);

    }

    /**
     * Tests another object for equality with this object.
     * 
     * @param object  the object to test.
     * 
     * @return A boolean.
     */
    public boolean equals(Object object) {
        if (object == null) {
            return false;
        }
        if (object == this) {
            return true;
        }
        if (super.equals(object) && object instanceof ArrowNeedle) {
            ArrowNeedle an = (ArrowNeedle) object;
            return this.isArrowAtTop == an.isArrowAtTop;
        }
        return false;
    }
    
}