能给我注释一下面函数吗,偶看不太懂

xkbin

Func SetBitmap($hGUI, $hImage, $iOpacity)
        Local $hScrDC, $hMemDC, $hBitmap, $hOld, $pSize, $tSize, $pSource, $tSource, $pBlend, $tBlend
        $hScrDC= _WinAPI_GetDC(0)
        $hMemDC= _WinAPI_CreateCompatibleDC($hScrDC)
        $hBitmap = _GDIPlus_BitmapCreateHBITMAPFromBitmap($hImage)
        $hOld= _WinAPI_SelectObject($hMemDC, $hBitmap)
        $tSize = DllStructCreate($tagSIZE)
        $pSize = DllStructGetPtr($tSize)
        DllStructSetData($tSize, "X", _GDIPlus_ImageGetWidth ($hImage))
        DllStructSetData($tSize, "Y", _GDIPlus_ImageGetHeight($hImage))
        $tSource = DllStructCreate($tagPOINT)
        $pSource = DllStructGetPtr($tSource)
        $tBlend= DllStructCreate($tagBLENDFUNCTION)
        $pBlend= DllStructGetPtr($tBlend)
        DllStructSetData($tBlend, "Alpha" , $iOpacity)
        DllStructSetData($tBlend, "Format", $AC_SRC_ALPHA)
        _WinAPI_UpdateLayeredWindow($hGUI, $hScrDC, 0, $pSize, $hMemDC, $pSource, 0, $pBlend, $ULW_ALPHA)
        _WinAPI_ReleaseDC (0, $hScrDC)
        _WinAPI_SelectObject($hMemDC, $hOld)
        _WinAPI_DeleteObject($hBitmap)
        _WinAPI_DeleteDC($hMemDC)
        _GDIPlus_ShutDown ()
EndFunc

asdf

获得当前的设备上下文，在上面绘制一个图像并设置alpha通道透明……
你不必看得懂，只要会用就行了。

xkbin

偶想活用它,当然得看明白是什么意思,要不然稀理糊涂了