Application: gvSIG desktop » gvSIG tools: ToolBox

/*********************************************************

 * Code adapted from Tim Lambert's Java Classes

 * http://www.cse.unsw.edu.au/~lambert/

 *********************************************************/

package es.unex.sextante.vectorTools.smoothLines;

import java.awt.Point;

import java.util.ArrayList;

import com.vividsolutions.jts.geom.Coordinate;

import com.vividsolutions.jts.geom.Geometry;

import com.vividsolutions.jts.geom.GeometryFactory;

import com.vividsolutions.jts.geom.LineString;

public class Bezier

         extends

            ControlCurve {

   public Bezier(final Geometry geom) {

      super(geom);

   }

   // the basis function for a Bezier spline

   static float b(final int i,

                  final float t) {

      switch (i) {

         case 0:

            return (1 - t) * (1 - t) * (1 - t);

         case 1:

            return 3 * t * (1 - t) * (1 - t);

         case 2:

            return 3 * t * t * (1 - t);

         case 3:

            return t * t * t;

      }

      return 0; //we only get here if an invalid i is specified

   }

   //evaluate a point on the B spline

   Point p(final int i,

           final float t) {

      float px = 0;

      float py = 0;

      for (int j = 0; j <= 3; j++) {

         px += b(j, t) * m_X[i + j];

         py += b(j, t) * m_Y[i + j];

      }

      return new Point((int) Math.round(px), (int) Math.round(py));

   }

   @Override

   public LineString getSmoothedLine(final int iSteps) {

      final ArrayList<Coordinate> coords = new ArrayList<Coordinate>();

      Point q = p(0, 0);

      coords.add(new Coordinate(q.x, q.y));

      for (int i = 0; i < m_X.length - 3; i += 3) {

         for (int j = 1; j <= iSteps; j++) {

            q = p(i, j / (float) iSteps);

            coords.add(new Coordinate(q.x, q.y));

         }

      }

      return new GeometryFactory().createLineString((Coordinate[]) coords.toArray(new Coordinate[0]));

   }

}