/// <summary>
/// Creates an arc by tree points P,Q and R.
/// </summary>
/// <param name="P">First point</param>
/// <param name="Q">Second point</param>
/// <param name="R">Third point</param>
public Arc(xy P, xy Q, xy R)
{
LineType2d L1 = new LineType2d((P + Q) * 0.5, (Q - P).normal());
LineType2d L2 = new LineType2d((Q + R) * 0.5, (R - Q).normal());
double Lam, Mue;
if (L1.Cross(L2, out Lam, out Mue))
{
Center = L1.Value(Lam);
aRadius = bRadius = Center.dist(P);
Alfa = getAngle(P);
Beta = getAngle(R);
ClockWise = ((R - Q) & (P - Q)) < 0;
}
}
/// <summary>
/// Overrides the <see cref="Curve.setAtang"/>-method
/// </summary>
/// <param name="value">starttangent</param>
protected override void setAtang(xy value)
{
_At = value;
atangSetted = true;
if (btangSetted)
{
double lam, mue;
LineType2d l1 = new LineType2d(A, value);
LineType2d l2 = new LineType2d(B, _Bt);
if (l1.Cross(l2, out lam, out mue))
{
ControlPoint = l1.Value(lam);
}
Dirty = true;
}
}
/// <summary>
/// Overrides the <see cref="Curve.Slice"/>-method.
/// </summary>
/// <param name="from"></param>
/// <param name="to"></param>
public override void Slice(double from, double to)
{
xy T1 = Derivation(from).normalize();
xy T2 = Derivation(to).normalize();
xy _A = Value(from);
xy _B = Value(to);
if ((System.Math.Abs(T1 & T2) < 0.001)
||
(System.Math.Abs(from - to) < 0.001))
{
ControlPoint = (_A + _B) * 0.5;
A = _A;
B = _B;
Dirty = true;
return;
}
LineType2d L1 = new LineType2d(_A, Derivation(from));
LineType2d L2 = new LineType2d(_B, Derivation(to));
double Lam = -1;
double Mue = -1;
L1.Cross(L2, out Lam, out Mue);
xy Halbierung = (_A + _B) * 0.5;
xy P1 = Value((from + to) * 0.5);
xy _ControlPoint = L1.Value(Lam);
double a = (P1 - Halbierung).length();
double b = (_ControlPoint - Halbierung).length();
Weight = a / (b - a);
if (Weight < 0)
{
}
A = _A;
B = _B;
ControlPoint = _ControlPoint;
Dirty = true;
}