procedure TForm1.selfshape;
{var
  ABitmap: TBitmap;
  I0, I1: integer;
begin
  ABitmap := TBitmap.Create;
  ABitmap.PixelFormat := pf1bit;
  ABitmap.Width := self.Width;
  ABitmap.Height := self.Height;
  //alles transparent machen:
  ABitmap.Canvas.Brush.Color := clBlack;
  ABitmap.Canvas.FillRect(0, 0, ABitmap.Width, ABitmap.Height);
  // auf gewünschte Form zuschneiden
  //brush.Color := clwhite;
  //Ellipse(0, 0, ABitmap.Width, ABitmap.Height);
  //Brush.Color := clWhite;
  ABitmap.Canvas.Brush.Color := clWhite;
  ABitmap.Canvas.;
  for I0 := 0 to Width-1 do
  begin
    for I1 := 0 to Height-1 do
    begin
      if Canvas.Pixels[I0, I1] <> clWhite then
      begin
        ABitmap.Canvas.Pixels[I0, I1] := clBlack;
      end;
    end;
  end;
  //rectangle(Button1.Left, Button1.Top, Button1.left + Button1.Width, button1.Top - 15);
  SetShape(ABitmap);
  ABitmap.Free;}