procedure TForm1.Button1Click(Sender: TObject);
var vl: TChartShape;
begin
         vl := TChartShape.Create(self);
         vl.ParentChart := Chart1;
         vl.Style := chasVertLine;
         vl.X1:= 100;
         vl.Y1:=  40;
         vl.X0:= 100;
         vl.Y0:=  90;
         vl.Title:='test title';
         vl.Font.Name := 'Comic Sans MS';
         vl.AfterDrawValues := VertLineTitle;
end;

// на событие после отрисовки прописываю:

procedure TForm1.VertLineTitle(Sender: TObject);
begin
    DrawText(0,10);
end;

// сам поворачиватель:

procedure TForm1.DrawText(aSeries, off: Integer);
var
  pcount, x1, y1, x2, y2: integer;
  l, x, y, a: double;
  logfont: TLogFont;
  font: Thandle;
begin
  pcount := Chart1.Series[aSeries].Count; //points in series

  x1 := Chart1.Series[aSeries].CalcXPos(pcount - 2);
  y1 := Chart1.Series[aSeries].CalcYPos(pcount - 2);

  x2 := Chart1.Series[aSeries].CalcXPos(pcount - 1);
  y2 := Chart1.Series[aSeries].CalcYPos(pcount - 1);
  x := x2 - x1;
  y := y2 - y1;
  l := Sqrt(x*x + y*y);
  If l=0 then l:=1;
  x := x/l;
  y := y/l;

  GetObject(Chart1.Canvas.Font.Handle, SizeOf(TLogFont), @LogFont);
  Chart1.Canvas.Font.Name := 'Comic Sans MS';

  LogFont.lfheight := 13;
  Logfont.lfwidth := 4;
  LogFont.lfEscapement := Round(900);
  LogFont.lfOrientation := LogFont.lfEscapement;

  Chart1.Canvas.Font.Handle := CreateFontIndirect(LogFont);
  Chart1.Canvas.TextOut(Round(x2-x*off+y*12),Round(y2-y*off-x*15),Chart1.Series[aSeries].Title);
  DeleteObject(font);
end;