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Re: [IndieUI Events] added UIZoomRequestEvent

From: Rick Byers <rbyers@google.com>
Date: Wed, 14 Nov 2012 11:53:10 -0800
Message-ID: <CAFUtAY9JXvBpr2u7Y2DmWYk=_E6V7xqjL=mZ5dUzJmf_GywyNQ@mail.gmail.com>
To: James Craig <jcraig@apple.com>
Cc: "public-indie-ui@w3.org" <public-indie-ui@w3.org>
Thanks James.
Are you coupling adding 'scale' to adding 'start/change/end' because the
desired semantics would be 'scale change since start'?  If instead the
semantics of 'scale' were 'incremental scale change from last event' then
perhaps we can separate it from the question of start/change/end?

Whether or not we need start/change/end for scale and pan is also a great
question.  It's certainly strictly more powerful, but I'm not sure how much
value it adds in practice.  One disadvantage of splitting it out is that I
wouldn't be surprised to find apps have bugs in scenarios where they are
intermixed (eg. panstart, zoomstart, zoomchange, zoomend, panchange,
zoomstart, etc...).

One interesting case to consider for both these questions is how multiple
simultaneous input modalities should be handled.  But perhaps that's
unusual enough that we don't need to worry too much about it (eg. it seems
almost certainly overkill to have a mechanism to support multiple pending
pan/zoom operations - i.e. with some source identifier to correlate change
events with a specific start event).

Thanks,
   Rick



On Tue, Nov 13, 2012 at 4:21 PM, James Craig <jcraig@apple.com> wrote:

> As noted in the working group charter, gestures and discussion of what
> they represent are explicitly listed as out-of-scope. Please try to phrase
> your requests or suggestions in a way that can be inferred as independent
> from a particular modality or user interface paradigm.
>
> I think the core of your request for a scale value is legitimate, but I
> don't think that would work well with the current 'discrete' events
> architecture, which is why I added this editorial note:
>
> This may need to be split into zoomstartrequest, zoomchangerequest, and
> zoomendrequest events.
>
> I've just updated the note to mention the possible addition of a scale
> attribute:
>
> This may need to be split into zoomstartrequest, zoomchangerequest, and
> zoomendrequest events, with an optional scale attribute.
>
>
>
> On Nov 13, 2012, at 2:13 PM, Rick Byers <rbyers@google.com> wrote:
>
> Great!
> To be able to use UIZoomRequestEvent from touch screen pinch gestures,
> we'd need a floating-point 'scale' value (pinch is only useful if the app
> can match the expansion to the finger movement).
>
> Rick
>
>
>
>
> On Sun, Nov 11, 2012 at 10:43 PM, James Craig <jcraig@apple.com> wrote:
>
>> Added UIZoomRequestEvent
>>
>> changeset
>> https://dvcs.w3.org/hg/IndieUI/rev/d98997ee66c7
>>
>> Latest:
>>
>> https://dvcs.w3.org/hg/IndieUI/raw-file/tip/src/indie-ui-events.html#UIZoomRequestEvent
>>
>>
>>
>
>
Received on Wednesday, 14 November 2012 19:53:57 GMT

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