SetBkMode

VB.Net

---

Imports System.Runtime.InteropServices

Module SetBKMode
    Const GDI32_DLL As String = "gdi32.dll"

    <DllImport(GDI32_DLL, EntryPoint:="SetBkMode")>
    Private Function setbkmode(hdc As IntPtr, bgmode As Integer) As Integer
    End Function

    Private Declare Function CreateCompatibleDC Lib "gdi32" (ByVal hdc As Integer) As Integer

    <DllImport("user32.dll", EntryPoint:="GetDC")>
    Public Function GetDC(ByVal ptr As IntPtr) As IntPtr
    End Function

    <DllImport("user32.dll")>
    Private Function ReleaseDC(ByVal hWnd As IntPtr, ByVal hDC As IntPtr) As  Boolean
    End Function

    Sub SetBKMode_Main()

        ' Create a device context (DC)
        ''Dim hdc As IntPtr = CreateCompatibleDC(IntPtr.Zero)
        ' Set the background mode to transparent
        ''setbkmode(hdc, 1) ' 1 = TRANSPARENT
        ' ...

        Dim srcBmp As New Bitmap(Image.FromFile("asciipad.png"))
        Dim hbm As IntPtr = srcBmp.GetHbitmap()
        Dim sdc As IntPtr = GetDC(IntPtr.Zero)
        Dim hdc As IntPtr = CreateCompatibleDC(sdc)
        ReleaseDC(IntPtr.Zero, sdc)

    End Sub
End Module