How to perform Zooming with CHtmlEditCtrl in MFC

Can anyone help me to perform zooming on CHtmlEditCtrl ?

I displayed my html docu开发者_如何学编程ment on CHtmlEditCtrl. Now I want my edit control to display same html document with different zooming level. I saw this feature in InternetExplorer8. Now I need to add this zooming feature to my MFC application.

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ExecWB(OLECMDID_ZOOM, 0, &vFontSize, NULL)

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Use OPTICAL_ZOOM as so;

VARIANT vaZoomFactor;
VariantInit (&vaZoomFactor);
V_VT(&vaZoomFactor) = VT_I4;
V_I4(&vaZoomFactor) = 50; //-- in this case, 50%
browserCtrl.ExecWB (OLECMDID_OPTICAL_ZOOM, OLECMDEXECOPT_DONTPROMPTUSER, &vaZoomFactor, NULL);