Application: gvSIG desktop » gvSIG tools: Vector editing

package org.gvsig.vectorediting.lib.prov.smoothline;

import org.gvsig.fmap.geom.GeometryLocator;

import org.gvsig.fmap.geom.GeometryManager;

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

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

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

public class Bezier extends ControlCurve {

    public Bezier(final Line line) {

        super(line);

    }

    // 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, int subtype) throws CreateGeometryException {

        GeometryManager geomManager = GeometryLocator.getGeometryManager();

        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 geomManager.createPoint((int) Math.round(px), (int) Math.round(py),subtype);

    }

    @Override

    public Line getSmoothedLine(final int iSteps, int subtype) throws CreateGeometryException {

        GeometryManager geomManager = GeometryLocator.getGeometryManager();

        Line line = geomManager.createLine(subtype);

        Point q = p(0, 0, subtype);

        line.addVertex(q);

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

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

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

                line.addVertex(q);

            }

        }

        return line;

    }

}