#include <GDIPlus.au3>
#include <GUIConstantsEx.au3>
#include <ScreenCapture.au3>
#include <WinAPIHObj.au3>

Example()

Func Example()
        _GDIPlus_Startup() ;initialize GDI+
        Local Const $iWidth = 150, $iHeight = 150
        Local $iColor = 0
        Local $hHBmp = _ScreenCapture_Capture("", 0, @DesktopHeight - $iHeight, $iWidth, @DesktopHeight) ;create a GDI bitmap by capturing an area on desktop
        Local $hBitmap = _GDIPlus_BitmapCreateFromHBITMAP($hHBmp) ;convert GDI to GDI+ bitmap
        _WinAPI_DeleteObject($hHBmp) ;release GDI bitmap resource because not needed anymore
        Local $iR, $iG, $iB, $iGrey
        For $iY = 0 To $iHeight - 1
                For $iX = 0 To $iWidth - 1
                        $iColor = _GDIPlus_BitmapGetPixel($hBitmap, $iX, $iY) ;get current pixel color
                        $iR = BitShift(BitAND($iColor, 0x00FF0000), 16) ;extract red color channel
                        $iG = BitShift(BitAND($iColor, 0x0000FF00), 8) ;extract green color channel
                        $iB = BitAND($iColor, 0x000000FF) ;;extract blue color channel
                        $iGrey = Hex(Int(($iR + $iG + $iB) / 3), 2) ;convert pixels to average greyscale color format
                        _GDIPlus_BitmapSetPixel($hBitmap, $iX, $iY, "0xFF" & $iGrey & $iGrey & $iGrey) ;set greyscaled pixel
                Next
        Next
        Local $hGUI = GUICreate("GDI+ Example (" & @ScriptName & ")", $iWidth, $iHeight) ;create a test GUI
        GUISetState(@SW_SHOW)

        Local $hGraphics = _GDIPlus_GraphicsCreateFromHWND($hGUI) ;create a graphics object from a window handle
        _GDIPlus_GraphicsDrawImage($hGraphics, $hBitmap, 0, 0) ;copy negative bitmap to graphics object (GUI)

        Do
        Until GUIGetMsg() = $GUI_EVENT_CLOSE

        ;cleanup GDI+ resources
        _GDIPlus_GraphicsDispose($hGraphics)
        _GDIPlus_Shutdown()
        GUIDelete($hGUI)
EndFunc   ;==>Example