/// <summary>
/// vypocita uhly definovane obloukem, uhly jsou v radianech
/// </summary>
/// <param name="start">pocatecni uhel oblouku</param>
/// <param name="angle">uhel sevreny pocatecnim a koncovym bodem oblouky, zaporny uhel - oblouk je ve smeru hodinovych rucicek</param>
/// <returns>pokud je objekt empty vrati false</returns>
public Circle2D?GetAngles(out double start, out double angle)
{
Circle2D c = Circle2D;
start = angle = 0;
if (c.IsEmpty)
{
return(null);
}
Vector b = Begin.Minus(c.Center);
double ab = Vector.AngleBetween(new Vector(1, 0), b);
double a = Vector.AngleBetween(b, End.Minus(c.Center));
if (ab < 0)
{
ab = 360 + ab;
}
if (a < 0)
{
a = 360 + a;
}
if (Clockwise)
{
a -= 360;
}
start = Funcs2D.Radian(ab);
angle = Funcs2D.Radian(a);
return(c);
}
/// <summary>
/// vrati tri body na oblouku
/// </summary>
/// <param name="k2">relativni delkova souradnice druheho bodu</param>
/// <returns>vrati pole bodu ret[0] = zacatek, ret[1] = bod na oblouku podle k2, ret[2] = konec</returns>
public Point[] ThreePoints(double k2 = 0.5)
{
if (IsEmpty)
{
return(null);
}
var ret = new Point[3];
ret[0] = Begin;
Circle2D c = Circle2D;
Vector b = Begin.Minus(c.Center);
double ab = Vector.AngleBetween(new Vector(1, 0), b);
double a = Vector.AngleBetween(b, End.Minus(c.Center));
if (ab < 0)
{
ab = 360 + ab;
}
if (a < 0)
{
a = 360 + a;
}
if (Clockwise)
{
a -= 360;
}
a = ab + (a * k2);
ret[1] = c.PointOn(Funcs2D.Radian(a));
ret[2] = End;
return(ret);
}
/// <summary>
/// oblouk zadany stredem , pocatecnim bodem a vektorem ne kterem lezi kocovy bod
/// </summary>
/// <param name="center">stred</param>
/// <param name="pt">pocatecni bod</param>
/// <param name="vector">vektor na kterem lezi koncovy bod</param>
/// <param name="shortangle">true = kratky oblouk (mezi nulou az 180 stupni), false = dlouhy oblouk (doplnek do 360 stupnu)</param>
public Arc2D(Point center, Point pt, Vector vector, bool shortangle = true)
{
Radius = Funcs2D.Distance(center, pt);
Begin = pt;
double a = Funcs2D.Radian(Vector.AngleBetween(new Vector(1, 0), vector));
End = Circle2D.PointOn(center, Radius, a);
if (!shortangle)
{
Radius *= -1;
}
a = Vector.AngleBetween(pt.Minus(center), vector);
Clockwise = !(a > 0 && shortangle || a < 0 && !shortangle);
}
/// <summary>
/// oblouk zadany stredem , pocatecnim bodem a uhlem
/// </summary>
/// <param name="center">stred</param>
/// <param name="pt">pocatecni bod</param>
/// <param name="angle">uhel v radianech , smer podle znamenka ( - = clockwise)</param>
public Arc2D(Point center, Point pt, double angle)
{
Radius = Funcs2D.Distance(center, pt);
Begin = pt;
if (Math.Abs(angle) > Math.PI * 2)
{
angle = angle % (Math.PI * 2);
}
Clockwise = angle < 0;
double a = Funcs2D.Radian(Vector.AngleBetween(new Vector(1, 0), pt.Minus(center)));
a += angle;
End = Circle2D.PointOn(center, Radius, a);
if (Math.Abs(angle) > Math.PI)
{
Radius *= -1;
}
}