CalculateRoundsArc

procedure CalculateRoundsArc(

  const p1: tFixedPoint;

  const p2: tFixedPoint;

  const p3: tFixedPoint;

  const xR: GR32.tFixed;

  out p21: tFixedPoint;

  out p22: tFixedPoint;

  out yC: tFixedPoint;

  out yStartAngle: Double;

  out yEndAngle: Double

);