/// <summary>
/// vytvori oblouk zadany pocatecnim bodem, vektorem ve kterm je koncovy bod a zdvihem v poloine usecky
/// </summary>
/// <param name="pt1">pocatecni bod oblouku</param>
/// <param name="v">vektor udavajici koncovy bod oblouky</param>
/// <param name="elevation">zdvih oblouku v polovine usecky [pt1,v]</param>
/// <returns></returns>
public static Arc2D Arc2DElevation(Point pt1, Vector v, double elevation)
{
Point pt2, pt3 = pt1.Plus(v);
pt2 = Funcs2D.PointOnLineLen(Funcs2D.PointOnLine(pt1, v, 0.5), Funcs2D.VectorNormal(v), elevation);
return(new Arc2D(pt1, pt2, pt3));
}
/// <summary>
/// oblouk tvoreny dvema po sobe jdoucimi useckami a polomerem
/// takzvane zaobleni rohu
/// pokud je polomer zaporny vytvori se tzv. vykousnuti se stredem ve spolecnem bode
/// objekt se nastavi na empty pokud jsou usecky rovnobezne nebo jedna z nich ma nulovou delku
/// </summary>
/// <param name="pt1">pocatecni bod prvni ridici usecky</param>
/// <param name="pt2">spolecny bod ridicich usecek</param>
/// <param name="pt3">konecny bod druhe ridici usecky</param>
/// <param name="radius">polomer zaobleni, zaporny polomer provede vykousnuti</param>
/// <param name="testPt">pokud se pocatecni nebo koncovy bod vypocita mimo usecku, objekt se nastavi na Empty</param>
public Arc2D(Point pt1, Point pt2, Point pt3, double radius, bool testPt = false)
{
// zjistim smer offsetu
double a = Vector.AngleBetween(pt2.Minus(pt1), pt3.Minus(pt2));
if (a > 0)
{
a = -Math.Abs(radius);
Clockwise = false;
}
else
{
a = Math.Abs(radius);
Clockwise = true;
}
// vypocitam prusecik offsetovanych primek
Point[] p1 = Funcs2D.LineOffset(pt1, pt2, a);
Point[] p2 = Funcs2D.LineOffset(pt2, pt3, a);
if (p1 == null || p2 == null || !TwoLine2D.CrossRel(p1[0], p1[1], p2[0], p2[1], out Point rr))
{
// tri body na jedne primce
Begin = pt1; End = pt3;
Radius = 0;
return;
}
if (radius > 0)
{
if (testPt)
{
if (!TwoLine2D.TestRelOnLine(TwoLine2D.CrossStatus.And, rr.X) || !TwoLine2D.TestRelOnLine(TwoLine2D.CrossStatus.And, rr.Y))
{
// body jsou mimo usecky
Begin = pt1; End = pt3;
Radius = 0;
return;
}
}
// koeficienty prenesu do puvodnich usecek a spocitam body
Begin = Funcs2D.PointOnLine(pt1, pt2, rr.X);
End = Funcs2D.PointOnLine(pt2, pt3, rr.Y);
Radius = radius;
}
else
{
Radius = -radius;
if (testPt)
{
if (Funcs2D.Distance(pt1, pt2) < Radius || Funcs2D.Distance(pt2, pt3) < Radius)
{
// body jsou mimo usecky
Begin = pt1; End = pt3;
Radius = 0;
return;
}
}
// bod na prvni primce ve vzdalenosti abs(radius) od spolecneho bodu
Begin = Funcs2D.PointOnLineLen(pt2, pt1, Radius);
// bod na druhe primce
End = Funcs2D.PointOnLineLen(pt2, pt3, Radius);
Clockwise = !Clockwise;
}
}
