Is it not possible to fill the Printer.Canvas with the method floodfill of
TCanvas?

procedure TForm1.Button1Click(Sender: TObject);
begin
  with Printer do
  with Canvas do
    begin
    BeginDoc;
    Brush.Color:=clSilver;
    FloodFill(200,300,clBlack,fsBorder);
    EndDoc;
  end;
end;

This won't work...