如何使字体旋转?

procedure TextOutAngle(x,y,aAngle,aSize: integer; txt: string);
var hFont, Fontold: integer;
    DC: hdc;
    Fontname: string;
begin
  if length(txt)= 0 then
    EXIT;
  DC:= Screen.ActiveForm.Canvas.handle;
  SetBkMode(DC, transparent);
  Fontname:= Screen.ActiveForm.Canvas.Font.Name;
  hFont:= CreateFont(-aSize,0, aAngle*10,0, fw_normal,0, 0,
                     0,1,4,$10,2,4,PChar(Fontname));
  Fontold:= SelectObject(DC, hFont);
  TextOut(DC,x,y,PChar(txt), length(txt));
  SelectObject(DC, Fontold);
  DeleteObject(hFont);
end;