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RE: IE implementation of navigator.maxTouchPoints

From: Jacob Rossi <Jacob.Rossi@microsoft.com>
Date: Fri, 12 Sep 2014 21:38:57 +0000
To: Jacob Rossi <Jacob.Rossi@microsoft.com>, Sangwhan Moon <sangwhan@iki.fi>, Rick Byers <rbyers@chromium.org>
CC: Sangwhan Moon <smoon@opera.com>, "public-pointer-events@w3.org" <public-pointer-events@w3.org>, David Bokan <bokan@chromium.org>
Message-ID: <b87140c0dcfb4b58b050a9153a893eb2@BY2PR03MB457.namprd03.prod.outlook.com>
Upon further discussion with the Windows input team, it looks like it's actually a Win7 bug that SM_DIGITIZER is false in these cases and that it's definitely not the case that this represents the difference between a touchscreen and a touchpad.  They advised against this using this pattern.  

Unfortunately, there is not a way to differentiate rogue touchpad drivers from touchscreen.  In Windows 8+, we're encouraging touchpad manufacturers to use Precision Touchpad, which enables the same scenarios without virtual touch drivers.

http://msdn.microsoft.com/en-us/library/windows/hardware/dn467317(v=vs.85).aspx 

-Jacob

-----Original Message-----
From: Jacob Rossi [mailto:Jacob.Rossi@microsoft.com] 
Sent: Friday, September 12, 2014 10:49 AM
To: Sangwhan Moon; Rick Byers
Cc: Sangwhan Moon; public-pointer-events@w3.org; David Bokan
Subject: RE: IE implementation of navigator.maxTouchPoints

On Wed, Sep 10, 2014 at 6:46 PM, Rick Byers <rbyers@chromium.org> wrote:
>
> Thank you!  Indeed it looks like this is Windows 7 only, and unlike IE we do still want to support touchscreens on Windows 7 (a small but non-trivial fraction of our touchscreen users are still on Windows 7).  It looks like SM_DIGITIZER is false in these cases, so I think we can try looking at SM_MAXIMUMTOUCHES only when SM_DIGITIZER is true. Sound reasonable to you?

I'm not an expert with these APIs. I have a mail thread with the Windows team that builds these APIs asking for advice and any implications of the design you suggested. I'll let you know what I find out.

-Jacob
Received on Friday, 12 September 2014 21:39:27 UTC

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