使用_SCREEN.PICTURE定义窗口图片如何实现自行'变比填充'

Question

给你段代码，放到程序的开始：
_Screen.AddObject("My_Screen","Image")
_Screen.My_Screen.BackStyle=0
_Screen.My_Screen.Stretch=1 &&等比填充   2为变比填充
_Screen.My_screen.Top=_Screen.Top
_Screen.My_Screen.Left=_Screen.Left
_Screen.My_Screen.Height=_Screen.Height
_Screen.My_Screen.Width=_Screen.Width
_Screen.My_Screen.Picture="kkk.bmp"
_Screen.My_Screen.Visible=.t.
_Screen.Refresh