Application: gvSIG desktop

/* gvSIG. Sistema de Informaci?n Geogr?fica de la Generalitat Valenciana

 *

 * Copyright (C) 2005 IVER T.I. and Generalitat Valenciana.

 *

 * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307,USA.

 */

package org.gvsig.rastertools.vectorizacion.fmap;

import java.awt.geom.Point2D;

import com.iver.cit.gvsig.fmap.core.GeneralPathX;

/**

 * Reimplementacion del GeneralPathX para que acepte curvas de Bezier

 * 

 * @version 28/08/2008

 * @author BorSanZa - Borja S?nchez Zamorano (borja.sanchez@iver.es)

 */

public class BezierPathX extends GeneralPathX {

        private static final long serialVersionUID = -77239133302246295L;

        private Point2D lastPoint      = new Point2D.Double(0, 0);

        private int     numberOfPoints = 1;

        /**

         * Crea un GeneralPathX definiendo cuantos cortes tendr? en las curvas de

         * Bezier. Cuanto mayor sea el numero de puntos, mejor definido estar?

         * @param numberOfPoints

         */

        public BezierPathX(int numberOfPoints) {

                this.numberOfPoints = numberOfPoints;

        }

        /**

         * Devuelve el punto de la curva de Bezier para el intervalo t

         * @param cp

         * @param t

         * @return

         */

        private Point2D pointOnCubicBezier(Point2D[] cp, double t) {

                double ax, bx, cx;

                double ay, by, cy;

                double tSquared, tCubed;

                Point2D result = new Point2D.Double();

                /* c?lculo de los coeficientes polinomiales */

                cx = 3.0 * (cp[1].getX() - cp[0].getX());

                bx = 3.0 * (cp[2].getX() - cp[1].getX()) - cx;

                ax = cp[3].getX() - cp[0].getX() - cx - bx;

                cy = 3.0 * (cp[1].getY() - cp[0].getY());

                by = 3.0 * (cp[2].getY() - cp[1].getY()) - cy;

                ay = cp[3].getY() - cp[0].getY() - cy - by;

                /* calculate the curve point at parameter value t */

                tSquared = t * t;

                tCubed = tSquared * t;

                result.setLocation((ax * tCubed) + (bx * tSquared) + (cx * t) + cp[0].getX(), (ay * tCubed) + (by * tSquared) + (cy * t) + cp[0].getY());

                return result;

        }

        /*

         * (non-Javadoc)

         * @see com.iver.cit.gvsig.fmap.core.GeneralPathX#curveTo(double, double, double, double, double, double)

         */

        public synchronized void curveTo(double x1, double y1, double x2, double y2, double x3, double y3) {

                Point2D points[] = new Point2D[4];

                points[0] = new Point2D.Double(lastPoint.getX(), lastPoint.getY());

                points[1] = new Point2D.Double(x1, y1);

                points[2] = new Point2D.Double(x2, y2);

                points[3] = new Point2D.Double(x3, y3);

                double dt = 1.0 / (numberOfPoints - 1);

                Point2D aux;

                for (int i = 0; i < numberOfPoints; i++) {

                        aux = pointOnCubicBezier(points, i * dt);

                        lineTo(aux.getX(), aux.getY());

                }

        }

        /*

         * (non-Javadoc)

         * @see com.iver.cit.gvsig.fmap.core.GeneralPathX#lineTo(double, double)

         */

        public synchronized void lineTo(double x, double y) {

                super.lineTo(x, y);

                lastPoint.setLocation(x, y);

        }

        /*

         * (non-Javadoc)

         * @see com.iver.cit.gvsig.fmap.core.GeneralPathX#moveTo(double, double)

         */

        public synchronized void moveTo(double x, double y) {

                super.moveTo(x, y);

                lastPoint.setLocation(x, y);

        }

}