[nik1967]

Ivan_009,

пример

Код:

[Setup]
AppName=My Application
AppVersion=1.5
DefaultDirName={pf}\My Application

[Languages]
Name: rus; MessagesFile: compiler:Languages\Russian.isl

[ Code]
const
  Radius = 55; // Тут сами экспериментируйте

function CreateRoundRectRgn(p1, p2, p3, p4, p5, p6: Integer): THandle; external 'CreateRoundRectRgn@gdi32 stdcall';
function SetWindowRgn(hWnd: HWND; hRgn: THandle; bRedraw: Boolean): Integer; external 'SetWindowRgn@user32 stdcall';

procedure ShapeForm(aForm: TForm; edgeSize: integer);
var
  FormRegion:LongWord;
begin
  FormRegion:=CreateRoundRectRgn(0,0,aForm.Width,aForm.Height,edgeSize,edgeSize);
  SetWindowRgn(aForm.Handle,FormRegion,True);
end;

procedure InitializeWizard();
begin
  ShapeForm(WizardForm, radius);
end;

Только пропадает прозрачность.