Calculates twice the area of a triangle for points specified in counter-clockwise order (if the points are specified in clockwise order the result will be negative). - Java 2D Graphics

Java examples for 2D Graphics:Angle

  1. HOME
  2. Java
  3. 2D Graphics
  4. Angle

Description

Calculates twice the area of a triangle for points specified in counter-clockwise order (if the points are specified in clockwise order the result will be negative).

Demo Code

/* --------------------------------------------------------===
 * Orson Charts : a 3D chart library for the Java(tm) platform
 * --------------------------------------------------------===
 * /*  w  ww.  j a  v  a2  s. c o m*/
 * (C)opyright 2013-2016, by Object Refinery Limited.  All rights reserved.
 * 
 * http://www.object-refinery.com/orsoncharts/index.html
 * 
 * This program 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.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 * 
 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. 
 * Other names may be trademarks of their respective owners.]
 * 
 * If you do not wish to be bound by the terms of the GPL, an alternative
 * commercial license can be purchased.  For details, please see visit the
 * Orson Charts home page:
 * 
 * http://www.object-refinery.com/orsoncharts/index.html
 * 
 */
//package com.java2s;

import java.awt.geom.Point2D;

public class Main {
    /**
     * Calculates twice the area of a triangle for points specified in 
     * counter-clockwise order (if the points are specified in clockwise order
     * the result will be negative).
     * 
     * @param a  the first point ({@code null} not permitted).
     * @param b  the second point ({@code null} not permitted).
     * @param c  the third point ({@code null} not permitted).
     * 
     * @return The area x 2.
     */
    public static double area2(Point2D a, Point2D b, Point2D c) {
        double ax = a.getX();
        double ay = a.getY();
        double bx = b.getX();
        double by = b.getY();
        double cx = c.getX();
        double cy = c.getY();
        return (ax - cx) * (by - cy) - (ay - cy) * (bx - cx);
    }
}

Related Tutorials