VB6 - Making a form transparent

December 2016

A program in VB6 or Visual Basic 6 can be used to make a form transparent in VB6. Some knowledge of programming concepts and languages like Visual Basic is required, to write programs in VB6. Basic knowledge of subroutines, if-else loops and Visual Basic functions are necessary to write programs in VB6. A program to make a form transparent in VB6 can be written by using VB6 functions like the SetLayeredWindowAttributes function and bit operations, in a user-defined subroutine. This user-defined subroutine will be called a form event, depending when the form loads.




Getting started

Here is a brief example of how to make a form transparent in Visual Basic.

Note: A color palette must be included for this to work.

In a module

Private Declare Function GetWindowLong Lib "user32" Alias "GetWindowLongA" (ByVal hWnd As Long, ByVal nIndex As Long) As Long     
Private Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" (ByVal hWnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
Private Declare Function SetLayeredWindowAttributes Lib "user32" (ByVal hWnd As Long, ByVal crKey As Long, ByVal bDefaut As Byte, ByVal dwFlags As Long) As Long

Private Const GWL_EXSTYLE As Long = (-20)
Private Const LWA_COLORKEY As Long = &H1
Private Const LWA_Defaut As Long = &H2
Private Const WS_EX_LAYERED As Long = &H80000

'
Public Function Transparency(ByVal hWnd As Long, Optional ByVal Col As Long = vbBlack, _
Optional ByVal PcTransp As Byte = 255, Optional ByVal TrMode As Boolean = True) As Boolean
' Return : True if there is no error.
' hWnd : hWnd of the window to make transparent
' Col : Color to make transparent if TrMode=False
' PcTransp : 0 Ã 255 >> 0 = transparent -:- 255 = Opaque
Dim DisplayStyle As Long
On Error GoTo Exit
VoirStyle = GetWindowLong(hWnd, GWL_EXSTYLE)
If DisplayStyle<> (DisplayStyle Or WS_EX_LAYERED) Then
DisplayStyle = (DisplayStyle Or WS_EX_LAYERED)
Call SetWindowLong(hWnd, GWL_EXSTYLE, DisplayStyle)
End If
Transparency = (SetLayeredWindowAttributes(hWnd, Col, PcTransp, IIf(TrMode, LWA_COLORKEY Or LWA_Defaut, LWA_COLORKEY)) <> 0)

Exit:
If Not Err.Number = 0 Then Err.Clear
End Function

Public Sub ActiveTransparency(M As Form, d As Boolean, F As Boolean, _
T_Transparency As Integer, Optional Color As Long)
Dim B As Boolean
If d And F Then
'Makes color (here the background color of the shape) transparent
'upon value of T_Transparency
B = Transparency(M.hWnd, Color, T_Transparency, False)
ElseIf d Then
'Makes form, including all components, transparent
'upon value of T_Transparency
B = Transparency(M.hWnd, 0, T_Transparency, True)
Else
'Restores the form opaque.
B = Transparency(M.hWnd,, 255, True)
End If
End Sub

As used in a form

Private Sub Form_Load()     
Dim i As Integer
'Ex: all transparent at ratio 140/255
'ActiveTransparency Me, True, False, 140, Me.BackColor
'Ex: Form transparent, visible component at ratio 140/255
'ActiveTransparency Me, True, True, 140, Me.BackColor

'Example display the form transparency degradation
ActiveTransparency Me, True, False, 0
Me.Show
For i = 0 To 255 Step 3
ActiveTransparency Me, True, False, i
Me.Refresh
Next i
End Sub

Related :

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