Minutes from Pointer Events WG call 27 May 2020

Dear all,

minutes from today's call are at 
https://www.w3.org/2020/05/27-pointerevents-minutes.html and also copied 
below:

Topics:
- should altitudeAngle default to 0 or pi/2 when not supported? 
https://github.com/w3c/pointerevents/issues/320
- It is not possible to generate one set of angle values from other set 
https://github.com/w3c/pointerevents/issues/321
- Translate between tiltX/tiltY and azimuth/altitude 
https://github.com/w3c/pointerevents/pull/322
- Virtual TPAC F2F

<scribe> Scribe: Patrick H. Lauke

- add altitudeAngle/azimuthAngle 
https://github.com/w3c/pointerevents/pull/316 - this has been merged, 
but led to some further questions

- should altitudeAngle default to 0 or pi/2 when not supported? 
https://github.com/w3c/pointerevents/issues/320

Patrick: giving overview of the discussion around Touch Events using 0, 
potential confusion if default in PE is pi/2

navid: mentions argument that we had around pressure, and how we decided 
to go for 0.5, to make PE "immediately usable" without having to special 
case stuff

so using pi/2 as default would make it immediately usable in the same way

using 0 as default would not be immediately usable

but pi/2 would be a more sensible fallback

other point about conversion: if we use pi/2 it makes it clearer for 
conversion

taking the newer approach - not having azimuthAngle/altitudeAngle 
properties, but only exposing tiltX/tiltY and the conversion functions, 
would make this moot

Patrick: so we have fundamental question of do we WANT to have 
azimuthAngle/altitudeAngle properties, OR sticking to original 
tiltX/tiltY only but offer functions for conversion only

how unusual is either approach? looking at other specs?

Navid: it seems unusual, but according what Domenic said the first 
approach is not allowed in WebIDL

<smaug> https://dom.spec.whatwg.org/#dom-mutationobserver-observe

Smaug: which part of WebIDL does this contravene?

Navid: the problem are the default values, we can't define that the 
defaults need to be backfilled/calculated
... maybe we shouldn't have any default values at all. But mouse etc do now

Smaug: looking at mutation event observer, it does define defaults and 
then (extra processing of how to do it...)

Navid: we should not have default values in dictionary, but in PE 
constructor

for previous solution, we should remove default values for the four 
properties

Smaug: and it can be defined in a backwards-compatible way

Navid: can stick to original plan, just remove default values. going to 
be a bit different from other event dictionaries

Smaug: think some events have *required* properties. in those cases they 
don't have default values

NAvid: 1) sticking to old solution. have to move stuff to constructor. 
domenic doesn't like this as it moves logic into the constructor. 2) 
other solution what liviu did with getter/setter functions / utility 
functions (though they feel perhaps odd/not related to PE directly)

Smaug: both are unusual, event APIs don't usually have this kind of logic

Navid: just remove default values of 
tiltX/tiltY/azimuthAngle/altitudeAngle (from dictionary)

Smaug: i think i'm ok with that. spec would need to say something 
similar to DOM spec for event observer

Navid: Patrick you ok with it?

Patrick: I'm ok with it...if somebody else does a PR, as it's beyond my 
understanding

Navid: Liviu you ok doing it?

Liviu: if we have the 4 attributes, if we convert tiltX/tiltY we don't 
lose anything (as they're long), but going from 
azimuthAngle/altitudeAngle to tilt we need some kind of grounding

Navid: wonder if we should change tilt, twist, etc to double

if it doesn't bite us now, it would surely do later

s/grounging/rounding

Navid: we need to do some form of rounding already anyway...is that bad?

Liviu: don't think it's a problem

Smaug: shouldn't be

Navid: we already do lose info, not a big problem then

first question from Patrick still on table.

if device has both values, populate all those values. if one or the 
other set is not reported by platform, convert the missing one. if none 
of them are reported/present, then fill in default values

Patrick: in principle i like using pi/2. it's more consistent/logical. 
if we do we need a big warning block in the spec. [some extra discussion 
about testing on iPad/Pencil and how apple's implementation for PE and 
stylus is actually spot on, testing with WebGL test]

Liviu: one aspect noticed during testing with Chromium - current authors 
can pass unrealistic values. are we ok with it?

Navid: do we want to do any clipping / clamping?

Smaug: what happens with conversion? i think it's fine, author 
responsibility

NAvid: what do we do if authors only pass on one value ... say just tiltX

Patrick: what happens with mouse events ?

Smaug: default value

Navid: so we need to define something in the spec that says if only one 
value in a pair (tiltX/tiltY, azimuthAngle/altitudeAngle) is sent, the 
other one is default value

Patrick: so on the default value for altitudeAngle when no value is 
passed on by platform, we're agreed that pi/2 makes more sense (and it 
needs a warning in spec that it's different from touch events)

Navid: yes

Smaug: yes

- It is not possible to generate one set of angle values from other set 
https://github.com/w3c/pointerevents/issues/321
Navid: this is what we said above. remove default values, and then put 
in extra logic

Patrick: and I think Liviu you said you were going to do it

Liviu: yes

- Translate between tiltX/tiltY and azimuth/altitude 
https://github.com/w3c/pointerevents/pull/322
Patrick: so as we're going tthe other way, we should close this one?

Navid: hopefully we won't hit any more issues around this, but for now yes

<NavidZ_> I agree. Let's close it

Patrick: one extra aspect I wanted to mention

Virtual TPAC F2F
Patrick: I completely missed the original deadline for responding about 
whether we wanted to have a specific time set aside for PEWG at virtual 
TPAC or not. Feel personally that, as most others are involved in far 
larger/more important groups that do benefit from structured virtual F2F 
time set aside compared to our small group, we're ok not to formally 
have a time set aside at the virtual TPAC

and carry on working on github and our semi-irregular calls to coordinate

Navid: I'm ok with not having a time at virtual TPAC, but would like to 
stick to TPAC timeline for roughly finishing up PEv3, and then maybe as 
discussed see if we want to morph into community group

Patrick: agree. also i think azimuth/altitude is the last big new 
feature we want. can't see any more big features we'd want to cram into 
a potential PEv4

How about you Olli, you ok with not having a formal meet at virtual TPAC 
and to aim for that time for finishing PEvĀ£?

Smaug: yes

Patrick: ok, think that's it for today. We'll meet again in 2 weeks or 4 
weeks, depending on progress on github issues here.

-- 
Patrick H. Lauke

https://www.splintered.co.uk/ | https://github.com/patrickhlauke
https://flickr.com/photos/redux/ | https://www.deviantart.com/redux
twitter: @patrick_h_lauke | skype: patrick_h_lauke

Received on Wednesday, 27 May 2020 15:53:53 UTC