[Lazarus] TStringGrid Orientation

[Jürgen Hestermann]

I am struggling with a 90 degree text output in a TStringGrid cell.
So far I have got it working with the following OnPrepareCanvas event procedure:

-------------------------------------------------
procedure TForm1.GridPrepareCanvas(Sender : TObject; aCol,aRow : Integer; aState : TGridDrawState);
begin // TForm1.GridPrepareCanvas
if (aCol=0) and ((aRow mod 5)=0) then
    begin
    with StringGrid1, Canvas, Font do
       begin
       Orientation := 900;
       Brush.Color := clGray;
       Color       := clYellow;
       end;
    end;
end; // TForm1.GridPrepareCanvas
-------------------------------------------------

but there is lots of (unnecessary) white space before and after the text as shown in
http://image-upload.de/image/es9ThD/cf9fc08cfd.png

Any ideas how to avoid this?