Add a note about the 300ms click delay

[RByers]

Talking about specific gestures is out of scope for the pointer events charter / specification. But hopefully we can at least have a note that describes the important impact touch-action has on the click delay? Here I attempt to do that without even using the word "zoom", WDYT?

See related twitter discussion: https://twitter.com/awfulben/status/642163198511026176

[RByers]

@jacobrossi WDYT?

[jacobrossi]

Good idea. Can you s/tap gesture/click event?

[RByers]

Thanks, how's this? (I'll squash all commits together before merging - don't need the intermediate history here).

[patrickhlauke]

From a reader's point of view, this version is a bit unsatisfactory as it doesn't make it clear why user agents must add the 300ms delay. perhaps after <code>click</code> event we could have to account for the possibility of a subsequent tap which may trigger further default behavior? still a very roundabout way of saying what could really be said in four simple words, though...

[RByers]

Seems like something like that could work. It could even be "subsequent touch action" - eg. Chrome has double-tap-drag (tap and then drag to zoom) which can have the same issue as double tap (though strangely doesn't today).

[patrickhlauke]

perhaps also change often must to typically

[jacobrossi]

Let me run this by some folks on my side to see how flexible we can be. :-)

[RByers]

perhaps also change often must to typically

done

I also added a bit more that should be uncontroversial: "(to resolve ambiguity around possible subsequent touches)".

Let me run this by some folks on my side to see how flexible we can be. :-)

Ok. Let me know if that's likely to take more than a couple days and we can land the uncontroversial wording for now, then hope to elaborate later :-)

[jacobrossi]

We can use Patrick's proposed suggestions (including calling double-tap / tap out specifically for clarity) since that would make this clearer. Perhaps we can add something like this just to make it clear what's out of scope?

Methods for determining a tap or double-tap gesture are out of scope for this specification.

[patrickhlauke]

[RByers]

Great, so like this then? (I squashed all the commits)

[RByers]

@patrickhlauke @jacobrossi let me know if either of you want to review the final text here before I merge it. Otherwise it sounds like it's safe to merge and tweak later as desired.

[patrickhlauke]

If I can be a right wordy pain in the neck... other behavior > other behaviors. Also, after mentioning the 300ms delay and auto, the note seems to just hang there and not follow through with the next part...that you can disable that delay. And although we're already in a note, that last sentence may need a bit of a lead-in. How's this:

<section class="note">Disabling some default touch behaviors may allow user agents to respond to other behaviors more quickly.  For example, with <code>auto</code> user agents typically add 300ms of delay before <code>click</code> to allow for double-tap gestures to be handled.  In these cases, explicitly setting <code>touch-action: none</code> or <code>touch-action: manipulation</code> will remove this delay. Note that the methods for determining a tap or double-tap gesture are out of scope for this specification.</section>

[RByers]

Thanks, I like that better (I was definitely getting sloppy) - using it verbatim. I think there's been enough discussion now that this can land, but happy to take more feedback in followup commits.