How to draw a rotated Ellipse?

I wrote a procedure "CentralRotatedEllipse" to rotate an ellipse. It works exactly enougth for simple graphics. The Ellipse is maked with two connected beziercurves. Rotatingpoint of the Ellipse is its centralpoint. The Parameter canvas for the Destinationcanvas, coordinates  like "common" Ellipse and in alpha the rotatingangle. The function "Rotate2DPoint" you have to put in your code too, its called by the CentralRotatedEllipse-Procedure.
And dont forget uses Math!

enjoy it


  function Rotate2DPoint(P,Fix :TPoint; alpha:double): TPoint;
  var
    sinus, cosinus : Extended;
  begin
    SinCos(alpha, sinus, cosinus);
    P.x := P.x - Fix.x;
    P.y := P.y - Fix.y;
    result.x := Round(p.x*cosinus + p.y*sinus)  +  fix.x ;
    result.y := Round(-p.x*sinus + p.y*cosinus) +  Fix.y;
  end;

  procedure CentralRotatedEllipse(Canvas : TCanvas; x1, y1, x2, y2:Integer; alpha : Extended);
  var PointList: array[0..6] of TPoint;  f : TPoint;  dk : Integer;
  begin
    dk := Round(0.654 * Abs(y2-y1));
    f.x := x1 + (x2-x1) div 2;
    f.y := (y1 + (y2-y1) div 2) -1;
    PointList[0] := Rotate2DPoint(Point(x1, f.y), f, Alpha) ;  // Startpoint
    PointList[1] := Rotate2DPoint(Point(x1,  f.y - dk), f, Alpha);  
    //Controlpoint of Startpoint first part
    PointList[2] := Rotate2DPoint(Point(x2- 1,  f.y - dk), f, Alpha);  
    //Controlpoint of secondpoint first part
    PointList[3] := Rotate2DPoint(Point(x2 -1 , f.y), f, Alpha);
    // Firstpoint of secondpart
    PointList[4] := Rotate2DPoint(Point(x2-1 , f.y + dk), f, Alpha);  
    // Controllpoint of secondpart firstpoint
    PointList[5] := Rotate2DPoint(Point(x1, f.y +  dk), f, Alpha);  
    // Conrollpoint of secondpart endpoint
    PointList[6] := PointList[0];   // Endpoint of
     // Back to the startpoint
    PolyBezier(canvas.handle, Pointlist[0], 7);
  end;