Comments

1. Claes Engelin
   02 Feb 2008 at 16:17

   As you will see, if you change the window style in the form load event, then the bitblting becomes very choppy.  If you wait and change the window style in the form unload event, just before the fade out effect, then you will see an ugly flicker.

   ==================================================================== 

   The only solution I find is capture the image of the window to the clipboard, and load a wide form with BorderStyle = 0 and put the image of the main form, unload the main form, and do the effect of transparency with this form, the capturewindow image code is how this:

    Option Explicit
   
   Public Type RECT_Type
   
      left As Long
      top As Long
      right As Long
      bottom As Long
   
   End Type
   
   'The following Public Declare statements are case sensitive.
   
   Public Declare Function GetActiveWindow Lib "User32" () As Long
   Public Declare Function GetDesktopWindow Lib "User32" () As Long
   Public Declare Sub GetWindowRect Lib "User32" (ByVal Hwnd As Long, _
                                       lpRect As RECT_Type)
   Public Declare Function GetDC Lib "User32" (ByVal Hwnd As Long) As Long
   Public Declare Function CreateCompatibleDC Lib "Gdi32" (ByVal hdc As Long) _
                                       As Long
   Public Declare Function CreateCompatibleBitmap Lib "Gdi32" (ByVal hdc _
                                       As Long, ByVal nWidth As Long, _
                                       ByVal nHeight As Long) As Long
   Public Declare Function SelectObject Lib "Gdi32" (ByVal hdc As Long, _
                                       ByVal hObject As Long) As Long
   Public Declare Function BitBlt Lib "Gdi32" (ByVal hDestDC As Long, _
                                       ByVal X As Long, ByVal Y _
                                       As Long, ByVal nWidth As Long, _
                                       ByVal nHeight As Long, _
                                       ByVal hSrcDC As Long, _
                                       ByVal XSrc As Long, _
                                       ByVal YSrc As Long, _
                                       ByVal dwRop As Long) As Long
   Public Declare Function OpenClipboard Lib "User32" (ByVal Hwnd As Long) As Long
   Public Declare Function EmptyClipboard Lib "User32" () As Long
   Public Declare Function SetClipboardData Lib "User32" (ByVal wFormat As Long, _
                                       ByVal hMem As Long) As Long
   Public Declare Function CloseClipboard Lib "User32" () As Long
   Public Declare Function ReleaseDC Lib "User32" (ByVal Hwnd As Long, _
                                       ByVal hdc As Long) As Long
   Public Declare Function DeleteDC Lib "Gdi32" (ByVal hdc As Long) As Long
   
   Global Const SRCCOPY = &HCC0020
   Global Const CF_BITMAP = 2
   
   Public Function CaptureWindowArea(AccessHwnd As Long)
      Dim DeskHwnd As Long
      Dim hdc As Long
      Dim hdcMem As Long
      Dim rect As RECT_Type
      Dim junk As Long
      Dim fwidth As Long, fheight As Long
      Dim hBitmap As Long
   
      'DoCmd.Hourglass True
   
      '---------------------------------------------------
      ' Get window handle to Windows and Microsoft Access
      '---------------------------------------------------
      DeskHwnd = GetDesktopWindow()
      AccessHwnd = GetActiveWindow()
   
      '---------------------------------------------------
      ' Get screen coordinates of Microsoft Access
      '---------------------------------------------------
      Call GetWindowRect(AccessHwnd, rect)
      fwidth = rect.right - rect.left
      fheight = rect.bottom - rect.top
   
      '---------------------------------------------------
      ' Get the device context of Desktop and allocate memory
      '---------------------------------------------------
      hdc = GetDC(DeskHwnd)
      hdcMem = CreateCompatibleDC(hdc)
      hBitmap = CreateCompatibleBitmap(hdc, fwidth, fheight)
   
      If hBitmap <> 0 Then
         junk = SelectObject(hdcMem, hBitmap)
   
         '---------------------------------------------
         ' Copy the Desktop bitmap to memory location
         ' based on Microsoft Access coordinates.
         '---------------------------------------------
         junk = BitBlt(hdcMem, 0, 0, fwidth, fheight, hdc, rect.left, _
                       rect.top, SRCCOPY)
   
         '---------------------------------------------
         ' Set up the Clipboard and copy bitmap
         '---------------------------------------------
         junk = OpenClipboard(DeskHwnd)
         junk = EmptyClipboard()
         junk = SetClipboardData(CF_BITMAP, hBitmap)
         junk = CloseClipboard()
      End If
   
      '---------------------------------------------
      ' Clean up handles
      '---------------------------------------------
      junk = DeleteDC(hdcMem)
      junk = ReleaseDC(DeskHwnd, hdc)
   
      'DoCmd.Hourglass False
   
   End Function
   
   
         
    

2. jc_23
   07 Mar 2007 at 10:26
   Im a computer student and I have a case study which is i will connect my databased to Media Player anyone can elp me please?..
3. Mitchell Howlett
   12 Aug 2005 at 02:59

   Thanks for the code. Works a treat, but the form is not entirely transparent - just semi-transparent

4. Joe C
   02 Aug 2004 at 08:39

   Yes, thanks for the help.  The following code is an example of the problem:
   

   
   Option Explicit
   

   
   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.dll" (ByVal _
   hwnd As Long, ByValcrKey As Long, ByVal bAlpha As Byte, ByVal dwFlags As Long) As Boolean
   

   
   Private Declare Function GetWindowLong Lib "user32" Alias "GetWindowLongA" _
   (ByVal hwnd As Long, ByVal nIndex As Long) As Long
   

   
   Private Declare Function BitBlt Lib "gdi32" (ByVal hDestDC As Long, ByVal X _
   As Long, ByVal Y As Long, ByVal nWidth As Long, ByVal nHeight As Long, ByVal _
   hSrcDC As Long, ByVal xSrc As Long, ByVal ySrc As Long, ByVal dwRop As Long) As Long
   

   
   Private Const SRCCOPY = &HCC0020
   Private Const LWAALPHA = 2
   Private Const GWLEXSTYLE = (-20)
   Private Const WSEXLAYERED = &H80000
   

   
   Dim iLeft As Integer
   

   
   Private Sub FormLoad()
      'Change window style to layered
      'Comment out the code for smooth scrolling (disables fade effect)
      SetWindowLong Form1.hwnd, GWLEXSTYLE, GetWindowLong(Form1.hwnd, _
      GWLEXSTYLE) Or WSEXLAYERED
      SetLayeredWindowAttributes Form1.hwnd, 0, 255, LWAALPHA
   End Sub
   

   
   Private Sub FormUnload(Cancel As Integer)
      'Can't change the window style here, because it creates flicker
      'Cut and paste the FormLoad code here to see    
   

   
      'Fade effect
      Timer1.Enabled = False
      Dim i As Integer
      For i = 255 To 0 Step -5
          SetLayeredWindowAttributes Me.hwnd, 0, i, LWA_ALPHA
          DoEvents
      Next
   End Sub
   

   
   Private Sub Timer1_Timer()
      'BitBLT scrolling
      iLeft = iLeft + 1
      If iLeft = ((Form1.Width + Picture1.Width) / Screen.TwipsPerPixelX) Then _
      iLeft = 0
      BitBlt Picture1.hDC, 0, 0, Picture1.Width, Picture1.Height, Form1.hDC, _
      iLeft, 0, SRCCOPY
   End Sub
   

   
   To use the code, add a small picture box to your form and add a timer (enable it, and set the interval to 1).  Then load a large picture into the form (the form1.picture property)
   

   
   As you will see, if you change the window style in the form load event, then the bitblting becomes very choppy.  If you wait and change the window style in the form unload event, just before the fade out effect, then you will see an ugly flicker.  
   

   
   I would like to change the window style to layered, only when i need it at form unload, but would like to avoid the flicker problem.
   

   
   Thanks for the help,
   -Joe

5. Yew Chin Sing
   30 Jul 2004 at 18:54

   if possible, can u send the code to me? maybe i wil help u to solve the problem
   

   
   again, when u use the code, it wil slow ur application down.

6. Joe C
   30 Jul 2004 at 13:49

   The problem with the putting the code in the form_load event is that the form will be significantly slowed down.  Since my application uses many bitblt's to the form, setting the form to a layered, but 255 opacity, destroyed the bitblting effects entirely.
   

   
   So now, i change the form to a layered in the form unload event, but I still have the associated flicker of changing the window style outside of the form_load event.
   

   
   Any ideas?

7. johnkarl
   02 Jul 2004 at 23:16

   I really want to thank you for sharing your code for making a form true transparent. your the best.
   

   
   thank you

8. Yew Chin Sing
   20 Feb 2004 at 22:22
   thx for the opinion....
9. Apodemus
   20 Feb 2004 at 11:07
   for better result i had to do like follows (on my pc the form was flickering while moving until i resize it)
   put the code in Form_Load event
    SetWindowLong Me.hwnd, GWL_EXSTYLE, GetWindowLong(Me.hwnd, GWL_EXSTYLE) Or WS_EX_LAYERED
    SetLayeredWindowAttributes Me.hwnd, 0, 255, LWA_ALPHA   'make it not transparent
   and no need to resize it
   and set the transparency when you want in the code
   for instance at the unload
   Private Sub Form_Unload(Cancel As Integer)
   Dim i As Integer
    For i = 255 To 0 Step -20
      SetLayeredWindowAttributes Me.hwnd, 0, i, LWA_ALPHA
      DoEvents
    Next
   End Sub
   flicker  free
   
   
   
10. Developer Fusion Bot
    01 Jan 1999 at 00:00

    This thread is for discussions of Making Windows Transparent.