Angle

function Angle(

  const px1: single;

  const py1: single;

  const px2: single;

  const py2: single

):single; overload;

function Angle(

  srcRadian: single;

  destRadian: single

):single; overload;

function Angle(

  const v1: TVector2f;

  const v2: TVector2f

):single; overload;