Application: gvSIG desktop

/* gvSIG. Geographic Information System of the Valencian Government

 *

 * Copyright (C) 2007-2008 Infrastructures and Transports Department

 * of the Valencian Government (CIT)

 *

 * 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 2

 * 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, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,

 * MA  02110-1301, USA.

 *

 */

package org.gvsig.fmap.geom.operation.perpendicular;

import java.awt.geom.Point2D;

import org.gvsig.fmap.geom.Geometry;

import org.gvsig.fmap.geom.Geometry.SUBTYPES;

import org.gvsig.fmap.geom.GeometryLocator;

import org.gvsig.fmap.geom.GeometryManager;

import org.gvsig.fmap.geom.exception.CreateGeometryException;

import org.gvsig.fmap.geom.operation.GeometryOperation;

import org.gvsig.fmap.geom.operation.GeometryOperationContext;

import org.gvsig.fmap.geom.operation.GeometryOperationException;

import org.gvsig.fmap.geom.primitive.Point;

/**

 * Returns an unit vector from two points.

 * 

 * @author gvSIG Team

 * @version $Id$

 *

 */

public class UnitVector extends GeometryOperation{

    public static final String NAME = "unitvector";

    private static GeometryManager geomManager = GeometryLocator.getGeometryManager();

    public static final int CODE = geomManager.getGeometryOperationCode(NAME);

    public Object invoke(Geometry geom, GeometryOperationContext ctx)

        throws GeometryOperationException {

        Point point1 = (Point)geom;

        Point point2 = (Point)ctx.getAttribute(PerpendicularOperationContext.SECOND_POINT);

        Point2D paux = new Point2D.Double(point2.getX() - point1.getX(),

            point2.getY() - point1.getY());

        double v = Math.sqrt(Math.pow(paux.getX(), 2d) +

            Math.pow(paux.getY(), 2d));

        paux = new Point2D.Double(paux.getX() / v, paux.getY() / v);

        try{

            return  geomManager.createPoint(paux.getX() / v, paux.getY() / v, SUBTYPES.GEOM2D);

        } catch (CreateGeometryException e) {

            throw new GeometryOperationException(e);

        }

    }

    public int getOperationIndex() {      

        return CODE;

    }    

}