Afficher du texte en transparent sur une Timage

procedure TForm1.Button1Click(Sender: TObject);
var
OldBkMode : integer;
begin
With Image1.Picture.Bitmap do
begin
Canvas.Font.Color := clBlue;
OldBkMode := SetBkMode(Canvas.Handle,Ord(TRANSPARENT));
Canvas.Font.Size := 13;
Canvas.TextOut(10, 10, 'Transparent Text!!');
SetBkMode(Canvas.Handle,OldBkMode);
end;
end;