J'aurais voulu savoir s'il était possible de modifier la fenetre principale et toutes les autres d'ailleurs sous VB 6 ???
Si oui comment ???

Voici mon code perso :
 
'dans un .BAS  
 
'Pour les regions
Private Const RGN_DIFF = 4
Type POINTAPI
        X As Long
        Y As Long
End Type
'utile pour les régions
Type Coord
  X As Long
  Y As Long
End Type
 
'Window Region declaration
Public Declare Function GetPixel Lib "gdi32" (ByVal hdc As Long, ByVal X As Long, ByVal Y As Long) As Long
Public Declare Function SetWindowRgn Lib "user32" (ByVal hwnd As Long, ByVal hRgn As Long, ByVal bRedraw As Boolean) As Long
Public Declare Function CreateRectRgn Lib "gdi32" (ByVal X1 As Long, ByVal Y1 As Long, ByVal X2 As Long, ByVal Y2 As Long) As Long
Public Declare Function CombineRgn Lib "gdi32" (ByVal hDestRgn As Long, ByVal hSrcRgn1 As Long, ByVal hSrcRgn2 As Long, ByVal nCombineMode As Long) As Long
Public Declare Function DeleteObject Lib "gdi32" (ByVal hObject As Long) As Long
Public Declare Function CreatePolygonRgn Lib "gdi32" (lpPoint As Coord, ByVal nCount As Long, ByVal nPolyFillMode As Long) As Long
Public Declare Function CreatePolyPolygonRgn Lib "gdi32" (lpPoint As Coord, lpPolyCounts As Long, ByVal nCount As Long, ByVal nPolyFillMode As Long) As Long
Dim CurRgn, TempRgn As Long  ' Region variables
 
Public Function AutoFormShape(bg As Form, transColor)
Dim X, Y As Integer
Dim success As Long
 
CurRgn = CreateRectRgn(0, 0, bg.ScaleWidth, bg.ScaleHeight)
While Y <= bg.ScaleHeight
    While X <= bg.ScaleWidth
        If GetPixel(bg.hdc, X, Y) = transColor Then
            TempRgn = CreateRectRgn(X, Y, X + 1, Y + 1)
            success = CombineRgn(CurRgn, CurRgn, TempRgn, RGN_DIFF)
            DeleteObject (TempRgn)
        End If
        X = X + 1
    Wend
        Y = Y + 1
        X = 0
Wend
success = SetWindowRgn(bg.hwnd, CurRgn, True)
DeleteObject (CurRgn)
 
End Function
 
'Dans le form
' il suffit de charger une image pour sa forme (propriété picture 'ou avec loadpicture) et ensuite (ici le fond est violet), seule 'la couleur en parametre est supprimée.
Private Sub Form_Load()
AutoFormShape Me, RGB(255, 0, 255)
End sub