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RE: Constructor question and mouseEvents compat

From: <Cathy.Chan@nokia.com>
Date: Wed, 10 Apr 2013 19:36:20 +0000
To: <mbrubeck@mozilla.com>, <Jacob.Rossi@microsoft.com>, <wjohnston@mozilla.com>, <public-pointer-events@w3.org>
Message-ID: <A46437648ECB3D4F852B077AFF9099F51C9A39A0@008-AM1MPN1-061.mgdnok.nokia.com>
For the change at 1.18 "a master pointer amongst the set of active pointers 
for each event type", should "for each event type" be "for each pointer type" 
instead?
- Cathy.


> -----Original Message-----
> From: ext Matt Brubeck [mailto:mbrubeck@mozilla.com]
> Sent: Tuesday, April 09, 2013 12:42 PM
> To: Jacob Rossi; Wesley Johnston; public-pointer-events@w3.org
> Subject: Re: Constructor question and mouseEvents compat
>
> On 4/8/2013 11:11 AM, Matt Brubeck wrote:
> > On 4/8/2013 10:49 AM, Jacob Rossi wrote:
> >> "The primary pointer is used to identify a master pointer amongst the
> >> set of active pointers for the pointer type.
> >
> > This part sounds good.
> >
> >>   This pointer will produce compatibility mouse events."
> >
> > This is still confusing, because with multiple primary pointers active
> > at once, one will generate mouse events and the others might not (or
> > will not?).  Maybe it should say "Only a primary pointer can generate
> > compatibility mouse events."
>
> Per our discussion on today's telcon, I made several minor changes to the
> spec to clarify that multiple primary pointers may be active at once:
> https://dvcs.w3.org/hg/pointerevents/rev/9e15214ee5c5
>
> > Then in section 8 we can expand on this with something like, "When
> > more than one primary pointer is active, the user agent MAY choose to
> > dispatch compatibility mouse events for only one of the primary
> > pointers." (Maybe that should be a "SHOULD" or "MUST"...)
> >
> > If my understanding is correct, we also need to update the mapping
> > algorithms in 8.1 and 8.2 to allow the user agent to terminate the
> > steps if it selects a different active pointer to generate mouse events.
>
> It seems my understanding was *not* correct here: User-agents are *not*
> expected to choose only one active pointer to generate mouse events.  If
> there is more than one primary pointer, they will all generate mouse events,
> effectively "fighting over" the mouse cursor.  This is not generally a 
> problem
> in practice, since users can just restrict themselves to a single input type 
> for
> applications that only handle mouse events.  Since the compatibility mapping
> is only intended for legacy compatibility, and the proposed additional steps
> do not provide a significant compatibility benefit, we will not add them.
>
> (User agents or platforms may perform "arbitration" on input before it
> reaches content, but that happens outside of the Pointer Events model and
> is out of scope for this working group. This would include things like "palm
> rejection" for touch+stylus input.)



Received on Wednesday, 10 April 2013 19:36:55 UTC

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