旋转一个点

按指定角度旋转一个点

const

 PIDiv180 = 0.017453292519943295769236907684886;

procedure Rotate(RotAng: Double; x, y: Double; var Nx, Ny: Double);

var

 SinVal: Double;

 CosVal: Double;

begin

 RotAng := RotAng * PIDiv180;

 SinVal := Sin(RotAng);

 CosVal := Cos(RotAng);

 Nx := x * CosVal - y * SinVal;

 Ny := y * CosVal + x * SinVal;

end;

(* End Of Rotate Cartesian Point*)