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Re: IE implementation of navigator.maxTouchPoints

From: Rick Byers <rbyers@chromium.org>
Date: Thu, 11 Sep 2014 15:15:07 -0400
Message-ID: <CAFUtAY_Fb7VTFgt+o1DdY3vqruSh5kBso2kH=9j_GEBu_oDi7w@mail.gmail.com>
To: Nikolay Lebedev <nicklebedev37@gmail.com>
Cc: David Bokan <bokan@google.com>, "public-pointer-events@w3.org" <public-pointer-events@w3.org>
On Thu, Sep 11, 2014 at 2:55 PM, Nikolay Lebedev <nicklebedev37@gmail.com>
wrote:

> Hi guys,
>
> btw, mozilla firefox has likely the same issue as Chrome:
> http://mxr.mozilla.org/mozilla-central/source/widget/windows/nsWindow.cpp#3611
> :). But afaik it doesn't have touch events enabled yet on desktop/win7 and
> likely such issue doesn't break anything.
>
> Anyway i'll file a bug in firefox's bugzilla to track it.
>

Thanks Nick!  Do you have the maxTouchPoints API enabled even when
touch/pointer events aren't enabled?  The complaint of Chrome users was
ultimately due to (IMHO broken) sites that were changing their
layout/functionality because they thought the users had a touch screen (and
so MUST be a "tablet").  So touch events aren't actually involved at all.


> Thanks,
> Nick
>
> On Thu, Sep 11, 2014 at 10:36 PM, David Bokan <bokan@google.com> wrote:
>
>> Beat me to the punch: https://codereview.chromium.org/563853002
>>
>> On Thu, Sep 11, 2014 at 2:31 PM, Rick Byers <rbyers@chromium.org> wrote:
>>
>>> Essentially yes (although I don't think that compiles - you mean
>>> IsTouchDevicePresent, not IsTouchEnabledDevice?).  I believe bokan@
>>> plans to land something like this ASAP.
>>>
>>> Thanks,
>>>    Rick
>>>
>>>
>>> On Thu, Sep 11, 2014 at 1:29 AM, Sangwhan Moon <smoon@opera.com> wrote:
>>>
>>>> Makes sense, is was this what you had in mind?
>>>>
>>>> https://gist.github.com/cynthia/fe95daed5322109f567c
>>>>
>>>> (I didn't actually check if this compiles, my work environment is 100%
>>>> *nix. :-()
>>>>
>>>> Cheers,
>>>> Sangwhan
>>>>
>>>> On Thu, Sep 11, 2014 at 10:46 AM, 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?
>>>>>
>>>>> Thanks,
>>>>> Rick
>>>>>
>>>>>
>>>>> On Wed, Sep 10, 2014 at 7:44 PM, Jacob Rossi <
>>>>> Jacob.Rossi@microsoft.com> wrote:
>>>>>
>>>>>>  Definitely happy to help here. Our code is roughly:
>>>>>>
>>>>>>
>>>>>>
>>>>>> lMaxTouchPoints = 0;
>>>>>>
>>>>>> if (Win8+)
>>>>>>
>>>>>> {
>>>>>>
>>>>>>     lMaxTouchPoints = GetSystemMetrics(SM_MAXIMUMTOUCHES);
>>>>>>
>>>>>> }
>>>>>>
>>>>>> return lMaxTouchPoints;
>>>>>>
>>>>>>
>>>>>>
>>>>>> The OS check is there because we don’t support touch in the IE
>>>>>> platform on Windows 7 and usage of touchscreen devices on Win7 is extremely
>>>>>> low (most have moved to Win8+).
>>>>>>
>>>>>> Have you seen reports of this on Windows 8/8.1 or just Windows 7?
>>>>>>
>>>>>>
>>>>>>
>>>>>> There definitely are touchpad drivers that like to install a fake
>>>>>> touch driver in order to fake zoom gestures (e.g. pinch to zoom). I don’t
>>>>>> think there’s a way for the Windows input stack to tell the difference
>>>>>> between that and an actual touchscreen. But if you’d like, I can loop you
>>>>>> in with our Win32 input team.
>>>>>>
>>>>>>
>>>>>>
>>>>>> -Jacob
>>>>>>
>>>>>>
>>>>>>
>>>>>> *From:* rbyers@google.com [mailto:rbyers@google.com] *On Behalf Of *Rick
>>>>>> Byers
>>>>>> *Sent:* Wednesday, September 10, 2014 10:26 AM
>>>>>> *To:* Jacob Rossi
>>>>>> *Cc:* public-pointer-events@w3.org; David Bokan
>>>>>> *Subject:* IE implementation of navigator.maxTouchPoints
>>>>>>
>>>>>>
>>>>>>
>>>>>> Hey Jacob,
>>>>>>
>>>>>> We're getting reports of some complaints of navigator.maxTouchPoints
>>>>>> returning 1 on Chrome when there is in fact no touchscreen.  IE11 correctly
>>>>>> returns 0.  http://crbug.com/352942.  Scott (from MS OpenTech) wrote the
>>>>>> code
>>>>>> <https://code.google.com/p/chromium/codesearch#chromium/src/ui/base/touch/touch_device_win.cc&q=MAXTOUCHPOINTS&sq=package:chromium&type=cs&l=17>
>>>>>> for this for us, basically just:
>>>>>>
>>>>>>
>>>>>>
>>>>>> int MaxTouchPoints() {
>>>>>>
>>>>>>   return GetSystemMetrics(SM_MAXIMUMTOUCHES);
>>>>>>
>>>>>> }
>>>>>>
>>>>>>
>>>>>>
>>>>>> Apparently, despite what we'd expect fro the MSDN docs, this is
>>>>>> insufficient.  Users report that it returns 1 in scenarios with both an
>>>>>> internal and external mouse plugged in - although we haven't been able to
>>>>>> reproduce it (and they've confirmed they see those values from the API
>>>>>> directly, so it's not some bug in chrome).
>>>>>>
>>>>>>
>>>>>>
>>>>>> Any chance you can share the algorithm with us that IE uses to
>>>>>> compute maxTouchPoints on windows?  Ideally Chrome and IE would always
>>>>>> agree here, and there's obviously some special cases.
>>>>>>
>>>>>>
>>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>>    Rick
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> Sangwhan Moon [Opera Software ASA]
>>>> Software Engineer | Tokyo, Japan
>>>>
>>>
>>>
>>
>
Received on Thursday, 11 September 2014 19:15:57 UTC

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