| gvSIG desktop 1

/*

 * Created on 10-feb-2005

 *

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

 * 

 * Copyright (C) 2004 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.

 *  

 * For more information, contact:

 *

 *  Generalitat Valenciana

 *   Conselleria d'Infraestructures i Transport

 *   Av. Blasco Ib??ez, 50

 *   46010 VALENCIA

 *   SPAIN

 *

 *      +34 963862235

 *   gvsig@gva.es

 *      www.gvsig.gva.es

 * 

 *    or

 * 

 *   IVER T.I. S.A

 *   Salamanca 50

 *   46005 Valencia

 *   Spain

 * 

 *   +34 963163400

 *   dac@iver.es

 */

package com.iver.cit.gvsig.fmap.edition;

import java.awt.Color;

import java.awt.Graphics;

import java.awt.Graphics2D;

import java.awt.geom.Arc2D;

import java.awt.geom.Line2D;

import java.awt.geom.Point2D;

import java.awt.geom.Rectangle2D;

/**

 * @author FJP

 *

 * TODO To change the template for this generated type comment go to

 * Window - Preferences - Java - Code Generation - Code and Comments

 */

public class UtilFunctions {

    static public Arc2D createCircle(Point2D p1, Point2D p2, Point2D p3) //, Graphics g)

    {

        double xC, yC, w, h;

        // Calculamos 2 secantes, tiramos perpendiculares por sus puntos

        // medios y obtenemos el centro. Luego calculamos el radio.

        // Puntos medios de los segmentos.

        double xm1, ym1, xm2, ym2;

        xm1 = (p1.getX() + p2.getX())/ 2.0;

        ym1 = (p1.getY() + p2.getY())/ 2.0;

        xm2 = (p2.getX() + p3.getX())/ 2.0;        

        ym2 = (p2.getY() + p3.getY())/ 2.0;

        /* g.setColor(Color.GRAY);

        g.draw3DRect((int)xm1, (int) ym1, 1, 1, true);

        g.draw3DRect((int)xm2, (int) ym2, 1, 1, true); */

        // Pendientes de las perpendiculares y constantes       

        double mP1=0, mP2=0, A1, A2;

        boolean bPerp1 = false, bPerp2 = false;

        if (p2.getY() - p1.getY() == 0)

        {

            A1 = ym1;

            bPerp1 = true;

        }

        else

        {

            mP1 = (p2.getX() - p1.getX()) /(p1.getY() - p2.getY());

            A1 = ym1 - xm1 * mP1;

        }

        if (p2.getY() - p3.getY() == 0)

        {

            A2 = ym2;

            bPerp2 = true;

        }

        else

        {

            mP2 = (p3.getX() - p2.getX()) /(p2.getY() - p3.getY());

            A2 = ym2 - xm2 * mP2;            

        }

        if (mP2 == mP1)

        {

            return null; // Error, 3 puntos alineados. No puede pasar un arco

        }

        else

        {

            xC = (A2 - A1)/(mP1-mP2);

            if (!bPerp1)

                yC = xC * mP1 + A1;

            else 

                yC = xC * mP2 + A2;

        }

        double Radio = p1.distance(xC, yC);

        double xR = xC - Radio ;

        double yR = yC - Radio ;

        w = 2.0* Radio;

        h = w;

        Rectangle2D.Double rBounds = new Rectangle2D.Double(xR,yR, w,h);

        Arc2D.Double resul = new Arc2D.Double(rBounds, 0.0, 360.0, Arc2D.OPEN);

		/* g.setColor(Color.RED);

		((Graphics2D) g).draw(resul);

		g.setColor(Color.BLUE);

		((Graphics2D) g).draw(rBounds);

		g.draw3DRect((int)p1.getX(), (int) p1.getY(), 1, 1, true);

		g.draw3DRect((int)p2.getX(), (int) p2.getY(), 2, 2, true);

		g.draw3DRect((int)p3.getX(), (int) p3.getY(), 1, 1, true);

		g.drawString("1", (int) p1.getX(), (int) p1.getY());

		g.drawString("2", (int) p2.getX(), (int) p2.getY());

		g.drawString("3", (int) p3.getX(), (int) p3.getY());

		g.drawString("C", (int) xC, (int) yC);

		g.draw3DRect((int)xC, (int) yC, 2, 2, true); */

        return resul;

    }

}