Form design

her er et eksempel på en femkantet form

type
  TForm1 = class(TForm)
    procedure FormCreate(Sender: TObject);
  private
    FRegion: THandle;
    procedure FreeRegion;
  public
    procedure CreateParams(var Params: TCreateParams); override;
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.CreateParams(var Params: TCreateParams);
begin
  inherited CreateParams(Params);
  Params.Style := WS_POPUP or WS_BORDER and not WS_MINIMIZE;
end;

procedure TForm1.FreeRegion;
begin
  if FRegion <> 0 then
  begin
    SetWindowRgn(Handle, 0, True);
    DeleteObject(FRegion);
    FRegion := 0;
  end;
end;

procedure TForm1.FormCreate(Sender: TObject);
type
  TPointsArray = array[0..4] of TPoint;

var
  pa: TPointsArray;
begin
  FreeRegion;

  with ClientRect do
  begin
    pa[0] := Point(Left + 50, Bottom);
    pa[1] := Point(Left + 1, Top + Bottom div 2);
    pa[2] := Point(Left + Right div 2, Top);
    pa[3] := Point(Right, Top + Bottom div 2);
    pa[4] := Point(Right - 50, Bottom);

    FRegion := CreatePolygonRgn(pa, 5, ALTERNATE);
  end;

  if FRegion <> 0 then
    SetWindowRgn(Handle, FRegion, True);
end;

end.