Une forme ronde ou oval ou ...

 

 

Private Declare Function CreateEllipticRgn Lib "gdi32" (ByVal X1 As Long, ByVal Y1 As Long, ByVal X2 As Long, ByVal Y2 As Long) As Long
Private Declare Function SetWindowRgn Lib "user32" (ByVal hWnd As Long, ByVal hRgn As Long, ByVal bRedraw As Boolean) As Long


Private Sub Form_Load()

Show 'The form!
SetWindowRgn hWnd,   CreateEllipticRgn(0, 0, 300, 200),   True

End Sub