OLECMDID_OPTICAL_ZOOM is not updated when pinch-to-zoom is performed on Win 8.1 and IE 11

Question

I need to get the current zoom level of the browser control.  In most cases I can, however, OLECMDID_OPTICAL_ZOOM (nor OLECMDID_ZOOM) is not updated when pinch-to-zoom is performed.  In case it matters, the code to get optical zoom is below.  Note that, Ctrl +/- do the same thing (graphically), and optic zoom IS updated in that case.

int GetOpticZoom()
{
	VARIANT vOut;
	VariantInit(&vOut);
	ExecWB(OLECMDID_OPTICAL_ZOOM, OLECMDEXECOPT_DONTPROMPTUSER, NULL, &vOut);
	return (vOut.vt == VT_I4 ? vOut.lVal : 100);
}

Can anyone explain why optic zoom is not being updated on Win 8.1 (IE 11) when pinch-to-zoom is performed?

Answer 1

You could use an OLE commands through ExecWB on the ActiveX instance: OLECMDID_ZOOM for text size and OLECMDID_OPTICAL_ZOOM for optical zoom. For example,

object pvaIn = 200; // A VT_I4 percentage ranging from 10% to 1000%
var browserInst = ((SHDocVw.IWebBrowser2)(browserContol.ActiveXInstance));
browserInst.ExecWB(SHDocVw.OLECMDID.OLECMDID_OPTICAL_ZOOM,
                   SHDocVw.OLECMDEXECOPT.OLECMDEXECOPT_DONTPROMPTUSER,
                   ref pvaIn, IntPtr.Zero);

please check out the links for details:

http://msdn.microsoft.com/en-us/library/windows/desktop/ms691264(v=vs.85).aspx

How to zoom content of Webgadget -

WPF WebBrowser control zoom in/out support

Hope it helps you.

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Answer 2

The ExecWB function I have above does that, which is why I said it works in most cases.  One case where zoom is not updated is when a pinch-to-zoom is done by the user.  I don't know if it's a bug in the browser control where it is not updating the optical zoom value internally for access to the outside, or if something else is going on.

Answer 3

I just found out that you cannot reproduce this issue unless your app is added to the FEATURE_NINPUT_LEGACYMODE and set to 0.  We need to disable legacy mode for many reasons.