How to get the accurate position of ole in a richedit?

hi
 
Recently, I have a question.
 
i want to do something when i click a ole in a richedit,but i find that i can not get the accurate position of ole.
 
Now,one way to get the position like this.
 
the "rcLastUpdate" is the i am using.
 
sometimes,it is not accurate,when the ole is not visible.
 

	STDMETHOD(Draw)(DWORD dwDrawAspect, LONG lindex, void *pvAspect,	DVTARGETDEVICE *ptd, HDC hicTargetDev, HDC hdcDraw,
	LPCRECTL prcBounds, LPCRECTL prcWBounds,
	BOOL (__stdcall * /*pfnContinue*/)(DWORD_PTR dwContinue),DWORD_PTR /*dwContinue*/)
	{
		if (prcBounds != NULL)
		{
			m_rcLastUpdate.left = prcBounds->left + 1; 
			m_rcLastUpdate.top = prcBounds->top + 1; 
			m_rcLastUpdate.right = prcBounds->right - 1; 
			m_rcLastUpdate.bottom = prcBounds->bottom - 1; 
		}
		IViewObject_Draw(dwDrawAspect, lindex, pvAspect, ptd, hicTargetDev, hdcDraw,
			prcBounds, prcWBounds);
		return 0;
	}

 
another way is that use "posfromchar()".
 
POINT posLeftBottom={PosFromChar(CPN).x, PosFromChar(CPN1).y }
 
cpn: the index of the ole .
CPN1: a char in the next line.
 
then i can get the position of the ole.
 
i think there must be a better solution.
 
so i want to know, how can i get the accurate position of ole?
 

thanks, recently asked more questions。 hoho,have more i should to learn.