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Re: [pointerevents] Add OS image dragging to non-normative reasons for pointercancel

From: Arthur Stolyar via GitHub <sysbot+gh@w3.org>
Date: Wed, 10 May 2017 20:43:51 +0000
To: public-pointer-events@w3.org
Message-ID: <issue_comment.created-300606717-1494449030-sysbot+gh@w3.org>
@NavidZ 
> I noted that your use case for counting how many fingers are down is also flawed. You cannot rely on the pairing of the events at all. You may receive a pointerup without receiving a pointerdown and vice versa.

That's weird. Why isn't that guaranteed? How someone should be able to implement multi-touch events if `pointerup` may not be called? I thought that the purpose of `pointercancel` -- if `pointerup` cannot be sent because finger/mouse/whatever is interrupted or out of surface then `pointercancel` is guaranteed to be called. Also many scripts indeed register `pointermove` on `pointerdown` and unregister on `pointerup`/`pointercancel`. This also brings question about `lostpointercapture` which is supposed to be called on `pointerup`/`pointerdown` (i.e. implicit capture loose).

IMO, if this is true when that's a bug in either browser or in the spec. And that also makes Touch Events more attractable since they always report touches count.

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Please view or discuss this issue at https://github.com/w3c/pointerevents/issues/205#issuecomment-300606717 using your GitHub account
Received on Wednesday, 10 May 2017 20:43:58 UTC

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