get Angle from two Point2D - Java 2D Graphics

Java examples for 2D Graphics:Point

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Description

get Angle from two Point2D

Demo Code

/* ------------------------------------------------------------------------
 * PlantUML : a free UML diagram generator
 * ------------------------------------------------------------------------
 *
 * (C) Copyright 2009, Arnaud Roques/*from   w w  w  . jav  a  2  s  .c om*/
 *
 * Project Info:  http://plantuml.sourceforge.net
 * 
 * This file is part of PlantUML.
 *
 * PlantUML is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * PlantUML 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 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.]
 *
 * Original Author:  Arnaud Roques
 *
 * Revision $Revision: 4236 $
 * 
 */
//package com.java2s;

import java.awt.geom.Point2D;

public class Main {
    static double getAngle(Point2D p1, Point2D p2) {
        if (p1.equals(p2)) {
            throw new IllegalArgumentException();
        }
        double a = -Math
                .atan2(p2.getY() - p1.getY(), p2.getX() - p1.getX());
        a = a * 180.0 / Math.PI;
        a -= 90;
        if (a >= 360.0) {
            a -= 360.0;
        }
        if (a < 0.0) {
            a += 360.0;
        }
        return a;
    }
}

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