Attribute VB_Name = "GlassForm"
Option Explicit

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 SetWindowRgn Lib "user32" (ByVal hwnd As Long, ByVal hRgn As Long, ByVal bRedraw As Long) As Long

Public Function GlassifyForm(frm As Form)
Const RGN_DIFF = 4
Const RGN_OR = 2

Dim outer_rgn As Long
Dim inner_rgn As Long
Dim wid As Single
Dim hgt As Single
Dim border_width As Single
Dim title_height As Single
Dim ctl_left As Single
Dim ctl_top As Single
Dim ctl_right As Single
Dim ctl_bottom As Single
Dim control_rgn As Long
Dim combined_rgn As Long
Dim ctl As Control

    If frm.WindowState = vbMinimized Then Exit Function

    ' Create the main form region.
    wid = frm.ScaleX(frm.Width, vbTwips, vbPixels)
    hgt = frm.ScaleY(frm.Height, vbTwips, vbPixels)
    outer_rgn = CreateRectRgn(0, 0, wid, hgt)

    border_width = (wid - frm.ScaleWidth) / 2
    title_height = hgt - border_width - frm.ScaleHeight
    inner_rgn = CreateRectRgn( _
        border_width, _
        title_height, _
        wid - border_width, _
        hgt - border_width)

    ' Subtract the inner region from the outer.
    combined_rgn = CreateRectRgn(0, 0, 0, 0)
    CombineRgn combined_rgn, outer_rgn, _
        inner_rgn, RGN_DIFF
On Error Resume Next
    ' Create the control regions.
    For Each ctl In frm.Controls
        If ctl.Container Is frm Then
            ctl_left = frm.ScaleX(ctl.Left, frm.ScaleMode, vbPixels) _
                + border_width
            ctl_top = frm.ScaleX(ctl.Top, frm.ScaleMode, vbPixels) _
                + title_height
            ctl_right = frm.ScaleX(ctl.Width, frm.ScaleMode, vbPixels) _
                + ctl_left
            ctl_bottom = frm.ScaleX(ctl.Height, frm.ScaleMode, vbPixels) _
                + ctl_top
            control_rgn = CreateRectRgn( _
                ctl_left, ctl_top, _
                ctl_right, ctl_bottom)
            CombineRgn combined_rgn, combined_rgn, _
                control_rgn, RGN_OR
        End If
    Next ctl

    ' Restrict the window to the region.
    SetWindowRgn frm.hwnd, combined_rgn, True
End Function


'Gebruik:
'GlassifyForm [Form]
'LET OP!

'de instellingen van het formulier moeten er zo uit zien:
'PaletteMode = 1
'Left = 0 (of 1 voor een verschuivend effect)
'ScaleLeft = 0
'ScaleMode = 3 (Pixel)
'ScaleTop = 0
'Top moet ingevuld zijn