/**
* Clip out a section of the arm, using internal parameter values
*
* @param c0 : start of section to clip out
* @param c1 : end of section to clip out; if < c0, c0 & c1 are swapped
*/
private void clip0(double c0, double c1) {
final boolean db = false;
if (c0 > c1) {
double t = c0;
c0 = c1;
c1 = t;
}
// array to store new clip elements in
DArray nc = new DArray();
if (db) {
System.out.println("clip " + Tools.f(c0) + "..." + Tools.f(c1));
}
for (int i = 0; i < visSeg.size(); i += 2) {
double t0 = visSeg.getDouble(i), t1 = visSeg.getDouble(i + 1);
if (db) {
System.out.println(" seg " + i + " " + Tools.f(t0) + "..." + Tools.f(t1));
}
// if this seg is outside clip region, leave intact (add it)
if (t0 >= c1 || t1 <= c0) {
nc.addDouble(t0);
nc.addDouble(t1);
continue;
}
if (t0 >= c0 && t1 <= c1) {
if (db) {
System.out.println(" clipping entire segment");
}
// remove entire segment, by skipping it
continue;
}
// add unclipped portion
if (t0 < c0) {
nc.addDouble(t0);
nc.addDouble(c0);
}
if (t1 > c1) {
nc.addDouble(c1);
nc.addDouble(t1);
}
}
visSeg = nc;
if (db) {
System.out.println(" after clipping:" + visSeg);
}
}
/**
* Determine closest point on hyperbolic arm to a point pt
*
* @param pt : point
* @return t value for closest point; not necessarily within clipped range
*/
public double closestPointTo(FPoint2 pt) {
final boolean db = false;
pt = toCurveSpace(pt, null);
double U = B + 1;
double V = -pt.y;
double W = B * pt.x;
Polyn p =
new Polyn( //
B * U * U, //
2 * B * U * V, //
B * V * V + A * U * U - W * W, //
2 * A * U * V, //
A * V * V //
);
if (db) Streams.out.println("closestPointTo, pt=" + pt + "\n" + p);
double ret = 0;
try {
DArray r = new DArray();
if (Math.abs(p.c(0)) < 1e-5) r.addDouble(0);
else p.solve(r);
if (r.isEmpty()) {
throw new FPError("can't find closest point, poly=\n" + p);
}
double bestDist = 0;
for (int i = 0; i < r.size(); i++) {
double t = r.getDouble(i);
FPoint2 apt = calcPoint(t);
double dist = apt.distance(pt);
if (i == 0 || dist < bestDist) {
bestDist = dist;
ret = t;
}
}
} catch (FPError e) {
Tools.warn("caught FPError");
// Streams.out.println("caught:\n" + e);
ret = (this.minParameter() + this.maxParameter()) * .5;
}
return ret;
}