/*
* (non-Javadoc)
*
* @see math.geom2d.Curve2D#position(math.geom2d.Point2D)
*/
public double position(Point2D point) {
double angle = Angle2D.horizontalAngle(ellipse.center(), point);
if (this.containsAngle(angle))
if (angleExtent > 0) return Angle2D.formatAngle(angle - startAngle);
else return Angle2D.formatAngle(startAngle - angle);
// If the point is not contained in the arc, return NaN.
return Double.NaN;
}
/** Returns a new CircleArc2D. t0 and t1 are position on circle. */
public CircleArc2D subCurve(double t0, double t1) {
double startAngle, extent;
if (this.direct) {
startAngle = t0;
extent = Angle2D.formatAngle(t1 - t0);
} else {
extent = -Angle2D.formatAngle(t1 - t0);
startAngle = Angle2D.formatAngle(-t0);
}
return new CircleArc2D(this, startAngle, extent);
}
/** Returns a new EllipseArc2D. */
public EllipseArc2D subCurve(double t0, double t1) {
// convert position to angle
t0 = Angle2D.formatAngle(startAngle + t0);
t1 = Angle2D.formatAngle(startAngle + t1);
// check bounds of angles
if (!Angle2D.containsAngle(startAngle, startAngle + angleExtent, t0, angleExtent > 0))
t0 = startAngle;
if (!Angle2D.containsAngle(startAngle, startAngle + angleExtent, t1, angleExtent > 0))
t1 = angleExtent;
// create new arc
return new EllipseArc2D(ellipse, t0, t1, angleExtent > 0);
}
public double project(Point2D point) {
double angle = ellipse.project(point);
// Case of an angle contained in the ellipse arc
if (this.containsAngle(angle)) {
if (angleExtent > 0) return Angle2D.formatAngle(angle - startAngle);
else return Angle2D.formatAngle(startAngle - angle);
}
// return either 0 or T1, depending on which extremity is closer.
double d1 = this.firstPoint().distance(point);
double d2 = this.lastPoint().distance(point);
return d1 < d2 ? 0 : abs(angleExtent);
}
/** Specify parameters of supporting ellipse, bounding angles and flag for direct ellipse. */
public EllipseArc2D(
double xc,
double yc,
double a,
double b,
double theta,
double start,
double end,
boolean direct) {
this.ellipse = new Ellipse2D(xc, yc, a, b, theta);
this.startAngle = start;
this.angleExtent = Angle2D.formatAngle(end - start);
if (!direct) this.angleExtent = this.angleExtent - PI * 2;
}
public double position(Point2D point) {
double angle = Angle2D.horizontalAngle(xc, yc, point.x(), point.y());
if (direct) return Angle2D.formatAngle(angle - theta);
else return Angle2D.formatAngle(theta - angle);
}
/**
* Returns the ellipse arc which refers to the reversed parent ellipse, with same start angle, and
* with opposite angle extent.
*/
public EllipseArc2D reverse() {
double newStart = Angle2D.formatAngle(startAngle + angleExtent);
return new EllipseArc2D(ellipse, newStart, -angleExtent);
}
/** Returns the angle associated with the given position */
public double getAngle(double position) {
if (position < 0) position = 0;
if (position > abs(angleExtent)) position = abs(angleExtent);
if (angleExtent < 0) position = -position;
return Angle2D.formatAngle(startAngle + position);
}