Wie die Zeichnung zu speichern?

#include <GDIPlus.au3>
#include <misc.au3>
#include <GUIConstantsEx.au3>
#include <WindowsConstants.au3>


;
; Draw by mouse
;
Opt("GUIOnEventMode", 1)
Opt("MouseCoordMode", 2)
$hwnd = GUICreate("Sample", 400, 400, -1, -1, -1, $WS_EX_LAYERED)
$button1 = GUICtrlCreateButton("save",10,5)
GUICtrlSetOnEvent(-1, "save")
GUISetBkColor(0xABCDEF, $hwnd)
GUISetOnEvent(-3, "close")
GUISetState()
_GDIPlus_Startup()
$graphics = _GDIPlus_GraphicsCreateFromHWND($hwnd)
;_GDIPlus_GraphicsClear($graphics, 0xFFFFFFFF)
$pen = _GDIPlus_PenCreate(0xFF000000,3,0)
_WINAPI_SetLayeredWindowAttributes($hwnd, 0xABCDEF,255)


$dll = DllOpen("user32.dll")




Do
    If _IsPressed("01", $dll) And WinActive("Sample") Then
        $oldpos=MouseGetPos()
        _GDIPlus_GraphicsDrawRect($graphics,$oldpos[0],$oldpos[1],1,1,$pen)
        Do
            $pos = MouseGetPos()
            _GDIPlus_GraphicsDrawLine($graphics,$oldpos[0],$oldpos[1],$pos[0],$pos[1],$pen)
            $oldpos=$pos
        Until Not _IsPressed("01", $dll)
    EndIf
    Sleep(25)
Until False


Func save()
	$bitmap = _GDIPlus_BitmapCreateFromGraphics ( 400, 400, $graphics)
	$hCtxt = _GDIPlus_ImageGetGraphicsContext($bitmap)
	_GDIPlus_GraphicsSetSmoothingMode($hCtxt, 2)
	_GDIPlus_GraphicsDrawImage($graphics, $bitmap, 0, 0)
	_GDIPlus_ImageSaveToFile($bitmap, @DesktopDir & "\qqqqqqqqqqqq.png")
EndFunc;==>save


Func close()
    _GDIPlus_PenDispose($pen)
    _GDIPlus_GraphicsDispose($graphics)
    _GDIPlus_Shutdown()
    Exit
EndFunc  ;==>close