RE: Thoughts on Gestures & pointerList

On Sun, Apr 14, 2013 at 7:29 AM, Scott González <scott.gonzalez@gmail.com> wrote:
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> On Sat, Apr 13, 2013 at 6:34 AM, François REMY <francois.remy.dev@outlook.com> wrote:
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>> Hi,
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>> I saw mentioned at some point that it was considered for v2 that a 'pointerList' property could be added to pointer events.
>>  
>> My take on the question is that it is probably a bad idea and should be avoided if possible. The reason is that pointer events are really meant to work on a per-pointer basis, and if you need to access the state of multiple pointers when performing an action, using an abstraction seems the best way to me.
>>  
>> So, if some pointerList property had to be defined, I would prefer the property to be defined on the gesture objects instead (the positive point is that the position of pointers should only be kept in memory if they are actually part of a gesture, and it makes sure people use the good technique to handle gestures instead of manually fiddling with the per-pointer events).
>>  
>> However, I'm wondering if someone has a good reason why we would want pointerList to be accessible during all the single-pointer events.
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> I'd personally rather see a method not tied to any event for getting a list of all active pointers.

I completely agree with Scott.  The Consumer Preview of IE10 had a pointer list on the event, and it didn't work well for the reasons Francois points out (pointer events fire per pointer). But it is nice to be able to access a list in scenarios like requestAnimationFrame(). So something like document.pointerList would be useful. We'll have to define rules for iframes and such. But I think it's doable when we get to V2.

-Jacob

Received on Monday, 15 April 2013 17:43:27 UTC