// Copyright 2001 FreeHEP.
package org.freehep.graphicsio;
import com.google.code.appengine.awt.geom.Point2D;
import java.io.IOException;
import java.util.Stack;
/**
* Implements cubics by approximating them using a polyline. Useful class for
* output formats that do NOT implement bezier curves at all, or if you need
* only straight lines.
*
* @author Mark Donszelmann
* @version $Id: CubicToLinePathConstructor.java 8584 2006-08-10 23:06:37Z duns $
*/
public abstract class CubicToLinePathConstructor extends
QuadToCubicPathConstructor {
private double resolution;
protected CubicToLinePathConstructor() {
this(0.025);
}
protected CubicToLinePathConstructor(double resolution) {
this.resolution = Math.abs(resolution);
}
public void cubic(double x1, double y1, double x2, double y2, double x3,
double y3) throws IOException {
// ControlSets are written at the end
Stack/*<ControlSet>*/ controls = new Stack/*<ControlSet>*/();
// System.out.println("Cubic "+x1+" "+y1+" "+x2+" "+y2+" "+x3+" "+y3);
Point2D p0 = new Point2D.Double(currentX, currentY);
Point2D p1 = new Point2D.Double(x1, y1);
Point2D p2 = new Point2D.Double(x2, y2);
Point2D p3 = new Point2D.Double(x3, y3);
// ControlSets to create the controls
Stack/*<ControlSet>*/ temps = new Stack/*<ControlSet>*/();
temps.push(new ControlSet(p0, p1, p2, p3));
while (!temps.empty()) {
ControlSet control = (ControlSet) temps.pop();
if (control.breadth() > resolution) {
temps.push(control);
temps.push(control.bisect());
} else {
controls.push(control);
}
}
/*tempSet[l++] = new ControlSet(p0, p1, p2, p3);
while (l > 0) {
ControlSet control1 = tempSet[--l];
double b = control1.breadth();
if (b > resolution) {
ControlSet control3 = control1.bisect();
tempSet[l++] = control1;
tempSet[l++] = control3;
} else {
controls.push(control1);
}
}*/
// write out control sets
// System.out.println(k);
while (!controls.empty()) {
Point2D p = ((ControlSet)controls.pop()).getPoint();
line(p.getX(), p.getY());
// System.out.println(control2.getPoint());
}
// store currentX and currentY
super.cubic(x1, y1, x2, y2, x3, y3);
}
class ControlSet {
private Point2D point0;
private Point2D point1;
private Point2D point2;
private Point2D point3;
public ControlSet(Point2D p0, Point2D p1, Point2D p2, Point2D p3) {
point0 = p0;
point1 = p1;
point2 = p2;
point3 = p3;
}
public double breadth() {
double f0 = point0.getX();
double f4 = point0.getY();
double f1 = point1.getX();
double f5 = point1.getY();
double f2 = point2.getX();
double f6 = point2.getY();
double f3 = point3.getX();
double f7 = point3.getY();
if ((Math.abs(f0 - f3) < resolution)
&& (Math.abs(f4 - f7) < resolution)) {
double f8 = Math.abs(f1 - f0) + Math.abs(f5 - f4);
double f10 = Math.abs(f2 - f0) + Math.abs(f6 - f4);
return Math.max(f10, f8);
} else {
double d0 = f4 - f7;
double d1 = f3 - f0;
double f12 = Math.sqrt(d0 * d0 + d1 * d1);
double d2 = f3 * f4 - f0 * f7;
double f9 = Math.abs((d0 * f2 + d1 * f6) - d2) / f12;
double f11 = Math.abs((d0 * f1 + d1 * f5) - d2) / f12;
return Math.max(f9, f11);
}
}
public ControlSet bisect() {
Point2D p0 = average(point0, point1);
Point2D p1 = average(point1, point2);
Point2D p2 = average(point2, point3);
Point2D p3 = average(p0, p1);
Point2D p4 = average(p1, p2);
Point2D p5 = average(p3, p4);
ControlSet controlset = new ControlSet(p5, p4, p2, point3);
point1 = p0;
point2 = p3;
point3 = p5;
return controlset;
}
public Point2D average(Point2D p1, Point2D p2) {
return new Point2D.Double((p1.getX() + p2.getX()) / 2.0,
(p1.getY() + p2.getY()) / 2.0);
}
public Point2D getPoint() {
return point3;
}
}
}