shapeutilities.java

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/* ========================================================================
 * JCommon : a free general purpose class library for the Java(tm) platform
 * ========================================================================
 *
 * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
 * 
 * Project Info:  http://www.jfree.org/jcommon/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.]
 * 
 * -------------------
 * ShapeUtilities.java
 * -------------------
 * (C)opyright 2003-2005, by Object Refinery Limited and Contributors.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   -;
 *
 * $Id: ShapeUtilities.java,v 1.15 2005/06/01 14:12:31 taqua Exp $
 *
 * Changes
 * -------
 * 13-Aug-2003 : Version 1 (DG);
 * 16-Mar-2004 : Moved rotateShape() from RefineryUtilities.java to here (DG);
 * 13-May-2004 : Added new shape creation methods (DG);
 * 30-Sep-2004 : Added createLineRegion() method (DG);
 *               Moved drawRotatedShape() method from RefineryUtilities class 
 *               to this class (DG);
 * 04-Oct-2004 : Renamed ShapeUtils --> ShapeUtilities (DG);
 * 26-Oct-2004 : Added a method to test the equality of two Line2D 
 *               instances (DG);
 * 10-Nov-2004 : Added new translateShape() and equal(Ellipse2D, Ellipse2D)
 *               methods (DG);
 * 11-Nov-2004 : Renamed translateShape() --> createTranslatedShape() (DG);
 * 07-Jan-2005 : Minor Javadoc fix (DG);
 * 11-Jan-2005 : Removed deprecated code in preparation for 1.0.0 release (DG);
 * 21-Jan-2005 : Modified return type of RectangleAnchor.coordinates() 
 *               method (DG);
 * 22-Feb-2005 : Added equality tests for Arc2D and GeneralPath (DG);
 * 16-Mar-2005 : Fixed bug where equal(Shape, Shape) fails for two Polygon
 *               instances (DG);
 *
 */

package org.jfree.util;

import java.awt.Graphics2D;
import java.awt.Polygon;
import java.awt.Shape;
import java.awt.geom.AffineTransform;
import java.awt.geom.Arc2D;
import java.awt.geom.Ellipse2D;
import java.awt.geom.GeneralPath;
import java.awt.geom.Line2D;
import java.awt.geom.PathIterator;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import java.util.Arrays;

import org.jfree.ui.RectangleAnchor;

/**
 * Utility methods for {@link Shape} objects.
 *
 * @author David Gilbert
 */
public class ShapeUtilities {

    /**
     * Prevents instantiation.
     */
    private ShapeUtilities() {
    }

    /**
     * Returns a clone of the specified shape, or <code>null</code>.  At the 
     * current time, this method supports cloning for instances of 
     * <code>Line2D</code>, <code>RectangularShape</code>, <code>Area</code> 
     * and <code>GeneralPath</code>.
     * <p>
     * <code>RectangularShape</code> includes <code>Arc2D</code>, 
     * <code>Ellipse2D</code>, <code>Rectangle2D</code>, 
     * <code>RoundRectangle2D</code>.
     * 
     * @param shape  the shape to clone (<code>null</code> permitted, 
     *               returns <code>null</code>).
     * 
     * @return A clone or <code>null</code>.
     */
    public static Shape clone(final Shape shape) {

        if (shape instanceof Cloneable) {
            try {
                return (Shape) ObjectUtilities.clone(shape);
            }
            catch(CloneNotSupportedException cnse) {
            }
        }
        final Shape result = null;
        return result;
    }
    
    /**
     * Tests two shapes for equality.  If both shapes are <code>null</code>, 
     * this method will return <code>true</code>. 
     * <p>
     * In the current implementation, the following shapes are supported: 
     * <code>Ellipse2D</code>, <code>Line2D</code> and <code>Rectangle2D</code> 
     * (implicit).
     * 
     * @param s1  the first shape (<code>null</code> permitted).
     * @param s2  the second shape (<code>null</code> permitted).
     * 
     * @return A boolean.
     */
    public static boolean equal(final Shape s1, final Shape s2) {
        if (s1 instanceof Line2D && s2 instanceof Line2D) {
            return equal((Line2D) s1, (Line2D) s2);
        }
        else if (s1 instanceof Ellipse2D && s2 instanceof Ellipse2D) {
            return equal((Ellipse2D) s1, (Ellipse2D) s2);
        }
        else if (s1 instanceof Arc2D && s2 instanceof Arc2D) {
            return equal((Arc2D) s1, (Arc2D) s2);   
        }
        else if (s1 instanceof Polygon && s2 instanceof Polygon) {
            return equal((Polygon) s1, (Polygon) s2);   
        }
        else if (s1 instanceof GeneralPath && s2 instanceof GeneralPath) {
            return equal((GeneralPath) s1, (GeneralPath) s2);   
        }
        else {
            // this will handle Rectangle2D...
            return ObjectUtilities.equal(s1, s2);
        }
    }

    /**
     * Compares two lines are returns <code>true</code> if they are equal or 
     * both <code>null</code>.
     * 
     * @param l1  the first line (<code>null</code> permitted).
     * @param l2  the second line (<code>null</code> permitted).
     * 
     * @return A boolean.
     */
    public static boolean equal(final Line2D l1, final Line2D l2) {
        if (l1 == null) {
            return (l2 == null);
        }
        if (l2 == null) {
            return false;
        }
        if (!l1.getP1().equals(l2.getP1())) {
            return false;
        }
        if (!l1.getP2().equals(l2.getP2())) {
            return false;
        }
        return true;
    }
    
    /**
     * Compares two ellipses and returns <code>true</code> if they are equal or 
     * both <code>null</code>.
     * 
     * @param e1  the first ellipse (<code>null</code> permitted).
     * @param e2  the second ellipse (<code>null</code> permitted).
     * 
     * @return A boolean.
     */
    public static boolean equal(final Ellipse2D e1, final Ellipse2D e2) {
        if (e1 == null) {
            return (e2 == null);
        }
        if (e2 == null) {
            return false;
        }
        if (!e1.getFrame().equals(e2.getFrame())) {
            return false;
        }
        return true;
    }
    
    /**
     * Compares two arcs and returns <code>true</code> if they are equal or 
     * both <code>null</code>.
     * 
     * @param a1  the first arc (<code>null</code> permitted).
     * @param a2  the second arc (<code>null</code> permitted).
     * 
     * @return A boolean.
     */
    public static boolean equal(final Arc2D a1, final Arc2D a2) {
        if (a1 == null) {
            return (a2 == null);
        }
        if (a2 == null) {
            return false;
        }
        if (!a1.getFrame().equals(a2.getFrame())) {
            return false;
        }
        if (a1.getAngleStart() != a2.getAngleStart()) {
            return false;   
        }
        if (a1.getAngleExtent() != a2.getAngleExtent()) {
            return false;   
        }
        if (a1.getArcType() != a2.getArcType()) {
            return false;   
        }
        return true;
    }
    
    /**
     * Tests two polygons for equality.  If both are <code>null</code> this 
     * method returns <code>true</code>.
     * 
     * @param p1  polygon 1 (<code>null</code> permitted).
     * @param p2  polygon 2 (<code>null</code> permitted).
     * 
     * @return A boolean.
     */    
    public static boolean equal(final Polygon p1, final Polygon p2) {
        if (p1 == null) {
            return (p2 == null);
        }
        if (p2 == null) {
            return false;
        }
        if (p1.npoints != p2.npoints) {
            return false;
        }
        if (!Arrays.equals(p1.xpoints, p2.xpoints)) {
            return false;
        }
        if (!Arrays.equals(p1.ypoints, p2.ypoints)) {
            return false;
        }
        return true;
    }
    
    /**
     * Tests two polygons for equality.  If both are <code>null</code> this 
     * method returns <code>true</code>.
     * 
     * @param p1  path 1 (<code>null</code> permitted).
     * @param p2  path 2 (<code>null</code> permitted).
     * 
     * @return A boolean.
     */    
    public static boolean equal(final GeneralPath p1, final GeneralPath p2) {
        if (p1 == null) {
            return (p2 == null);
        }
        if (p2 == null) {
            return false;
        }
        if (p1.getWindingRule() != p2.getWindingRule()) {
            return false;
        }
        PathIterator iterator1 = p1.getPathIterator(null);
        PathIterator iterator2 = p1.getPathIterator(null);
        double[] d1 = new double[6];
        double[] d2 = new double[6];
        boolean done = iterator1.isDone() && iterator2.isDone();
        while (!done) {
            if (iterator1.isDone() != iterator2.isDone()) {
                return false;   
            }
            int seg1 = iterator1.currentSegment(d1);
            int seg2 = iterator2.currentSegment(d2);
            if (seg1 != seg2) {
                return false;   
            }
            if (!Arrays.equals(d1, d2)) {
                return false;   
            }
            iterator1.next();
            iterator2.next();
            done = iterator1.isDone() && iterator2.isDone();
        }
        return true;
    }
    
    /**
     * Creates and returns a translated shape.
     * 
     * @param shape  the shape (<code>null</code> not permitted).
     * @param transX  the x translation (in Java2D space).
     * @param transY  the y translation (in Java2D space).