[GUI管理] 请问如何清除GDI创建的文字和图形呀

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


_Main()

Func _Main()
        Local $hGUI, $hGraphic, $hBrush, $hFormat, $hFamily, $hFont, $tLayout
        Local $sString = "Hello world", $aInfo

        ; 创建 GUI
        $hGUI = GUICreate("GDI+", 400, 300)
        GUISetState()

        ; 描绘字符串
        _GDIPlus_Startup()
        $hGraphic = _GDIPlus_GraphicsCreateFromHWND($hGUI)
        $hBrush = _GDIPlus_BrushCreateSolid(0xFF00007F)
        $hFormat = _GDIPlus_StringFormatCreate()
        $hFamily = _GDIPlus_FontFamilyCreate("Arial")
        $hFont = _GDIPlus_FontCreate($hFamily, 12, 2)
        $tLayout = _GDIPlus_RectFCreate(140, 110, 0, 0)
        $aInfo = _GDIPlus_GraphicsMeasureString($hGraphic, $sString, $hFont, $tLayout, $hFormat)
        _GDIPlus_GraphicsDrawStringEx($hGraphic, $sString, $hFont, $aInfo[0], $hFormat, $hBrush)

        ; 循环直到用户退出
        Do
        Until GUIGetMsg() = $GUI_EVENT_CLOSE
        $myWinPos = WinGetPos($hGUI)
        $tPoint = _WinAPI_CreateRect($myWinPos[0], $myWinPos[1], $myWinPos[0] + $myWinPos[2], $myWinPos[1] + $myWinPos[3])
        _WinAPI_RedrawWindow(_WinAPI_GetDesktopWindow(), $tPoint, 0, $RDW_INVALIDATE + $RDW_ALLCHILDREN)
        ; MsgBox(0,1,_GDIPlus_GraphicsClear($hGraphic))
        ; 清理资源
        _GDIPlus_FontDispose($hFont)
        _GDIPlus_FontFamilyDispose($hFamily)
        _GDIPlus_StringFormatDispose($hFormat)
        _GDIPlus_BrushDispose($hBrush)
        _GDIPlus_GraphicsDispose($hGraphic)
        _GDIPlus_Shutdown()

        Do
        Until GUIGetMsg() = $GUI_EVENT_CLOSE

EndFunc   ;==>_Main