Альфа - наложение - полупрозрачность

Private Const GWL_EXSTYLE = (-20)
Private Const WS_EX_LAYERED As Long = &H80000
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 l1 As Long, ByVal l2 As Long, ByVal l3 As Long) As Long
 
 
Private Sub Command1_Click()
    Const Alpha = 450
    If Command1.Caption = "Включить" Then
        Command1.Caption = "Отключить"
        SetWindowLong hwnd, GWL_EXSTYLE, GetWindowLong(hwnd, GWL_EXSTYLE) Or WS_EX_LAYERED
        SetLayeredWindowAttributes hwnd, 0, Alpha, 2
    Else
        SetWindowLong hwnd, GWL_EXSTYLE, 0
        Command1.Caption = "Включить"
    End If
End Sub
 
Private Sub Form_Load()
    Command1.Caption = "Включить"
End Sub

' Простой регион
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 Long) As Long
Private Declare Function CombineRgn Lib "gdi32" (ByVal hDestRgn As Long, ByVal hSrcRgn1 As Long, ByVal hSrcRgn2 As Long, ByVal nCombineMode As Long) As Long
Private Declare Function DeleteObject Lib "gdi32" (ByVal hObject As Long) As Long
 
Private Const RGN_AND = 1
Private Const RGN_COPY = 5
Private Const RGN_DIFF = 4
Private Const RGN_OR = 2
Private Const RGN_XOR = 3
 
Private Sub Form_Load()
    Dim hEx As Long, hIn As Long
    Me.ScaleMode = vbPixels
    hEx = CreateEllipticRgn(0, 0, Me.ScaleWidth, Me.ScaleHeight)   ' Создаем внешний круг
    hIn = CreateEllipticRgn(100, 100, Me.ScaleWidth - 100, Me.ScaleHeight - 100) ' Создаем внутренний круг
    CombineRgn hEx, hEx, hIn, RGN_DIFF                             ' Вырезаем из внешнего внутренний
    DeleteObject hIn
    SetWindowRgn Me.hWnd, hEx, 0
End Sub

' Ïðîçðà÷íîñòü ColorKey
 
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 bAlpha As Byte, ByVal dwFlags As Long) As Long
 
Const LWA_COLORKEY = &H1
Const GWL_EXSTYLE = (-20)
Const WS_EX_LAYERED = &H80000
 
Private Sub Form_Load()
   Dim Style As Long
   Style = GetWindowLong(Me.hwnd, GWL_EXSTYLE) Or WS_EX_LAYERED
   SetWindowLong Me.hwnd, GWL_EXSTYLE, Style
   SetLayeredWindowAttributes Me.hwnd, vbWhite, 0, LWA_COLORKEY ' Белый цвет на форме делаем прозрачным
End Sub

    Me.Refresh
    DoEvents

    Me.Hide
    Me.Show
    DoEvents