/* Copyright (C) 2005-2011 Fabio Riccardi */
package com.lightcrafts.ui.region.curves;
import java.util.ArrayList;
import java.awt.geom.GeneralPath;
import java.awt.geom.Point2D;
import java.awt.*;
/** An AbstractCurve whose updateShape() generates a closed quadratic
* B-spline.
*/
public class QuadraticBasisSpline extends AbstractCurve {
static ArrayList Bases = new ArrayList();
static void ensureBases(int count) {
while (Bases.size() < count) {
int i = Bases.size();
BasisFunction basis = new QuadraticBasisFunction(i);
Bases.add(basis);
}
}
// Update "shape" and "segments" from the current value of "points":
void updateShape() {
if (points.size() < 2) {
shape = null;
segments.clear();
return;
}
// Pad out the control point list using wraparound,
// to make a closed spline:
ArrayList extraPoints = new ArrayList(points);
extraPoints.add(0, points.get(points.size() - 1));
extraPoints.add(points.get(0));
GeneralPath path = new GeneralPath();
int m = extraPoints.size();
ensureBases(m);
segments.clear();
// Iterate over segments:
for (int i=2; i<m; i++) {
Polynomial xPoly = new Polynomial(0);
Polynomial yPoly = new Polynomial(0);
// Iterate over control points:
for (int j=0; j<m; j++) {
Point2D p = (Point2D) extraPoints.get(j);
BasisFunction basis = (BasisFunction) Bases.get(j);
double px = p.getX();
double py = p.getY();
Polynomial xSeg = basis.getSegment(i).multiply(px);
Polynomial ySeg = basis.getSegment(i).multiply(py);
xPoly = xPoly.add(xSeg);
yPoly = yPoly.add(ySeg);
}
xPoly = xPoly.translate(i);
yPoly = yPoly.translate(i);
Shape curve = Polynomial.createShape(xPoly, yPoly);
segments.add(curve);
path.append(curve, true);
}
path.closePath();
shape = path;
}
}