Java tutorial
/* * JCommon : a free general purpose class library for the Java(tm) platform * * * (C) Copyright 2000-2008, 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., 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.] * * ------------------- * ShapeUtilities.java * ------------------- * (C)opyright 2003-2008, by Object Refinery Limited and Contributors. * * Original Author: David Gilbert (for Object Refinery Limited); * Contributor(s): -; * * $Id: ShapeUtilities.java,v 1.18 2008/06/02 06:58:28 mungady 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); * 01-Jun-2008 : Fixed bug in equal(GeneralPath, GeneralPath) method (DG); * */ import java.awt.Shape; import java.awt.geom.GeneralPath; import java.awt.geom.Line2D; /** * Utility methods for {@link Shape} objects. * * @author David Gilbert */ public class Main { /** * Creates a region surrounding a line segment by 'widening' the line * segment. A typical use for this method is the creation of a * 'clickable' region for a line that is displayed on-screen. * * @param line the line (<code>null</code> not permitted). * @param width the width of the region. * * @return A region that surrounds the line. */ public static Shape createLineRegion(final Line2D line, final float width) { final GeneralPath result = new GeneralPath(); final float x1 = (float) line.getX1(); final float x2 = (float) line.getX2(); final float y1 = (float) line.getY1(); final float y2 = (float) line.getY2(); if ((x2 - x1) != 0.0) { final double theta = Math.atan((y2 - y1) / (x2 - x1)); final float dx = (float) Math.sin(theta) * width; final float dy = (float) Math.cos(theta) * width; result.moveTo(x1 - dx, y1 + dy); result.lineTo(x1 + dx, y1 - dy); result.lineTo(x2 + dx, y2 - dy); result.lineTo(x2 - dx, y2 + dy); result.closePath(); } else { // special case, vertical line result.moveTo(x1 - width / 2.0f, y1); result.lineTo(x1 + width / 2.0f, y1); result.lineTo(x2 + width / 2.0f, y2); result.lineTo(x2 - width / 2.0f, y2); result.closePath(); } return result; } }