Creates a region surrounding a line segment by 'widening' the line segment. - Java 2D Graphics

Java examples for 2D Graphics:Line

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Description

Creates a region surrounding a line segment by 'widening' the line segment.

Demo 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.//from  w  w w. j  a v a  2s .  com
 *
 * 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):   -;
 *
 * 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);
 * 20-Jun-2007 : Copied from JCommon (DG);
 * 02-Jun-2008 : Fixed bug in equal(GeneralPath, GeneralPath) (DG);
 * 05-Nov-2008 : Added clipLine() method (DG);
 *
 */
//package com.java2s;

import java.awt.Shape;

import java.awt.geom.GeneralPath;
import java.awt.geom.Line2D;

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(Line2D line, float width) {
        GeneralPath result = new GeneralPath();
        float x1 = (float) line.getX1();
        float x2 = (float) line.getX2();
        float y1 = (float) line.getY1();
        float y2 = (float) line.getY2();
        if ((x2 - x1) != 0.0) {
            double theta = Math.atan((y2 - y1) / (x2 - x1));
            float dx = (float) Math.sin(theta) * width;
            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;
    }
}

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