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Draft Minutes: 25 January 2011 call

From: Arthur Barstow <art.barstow@nokia.com>
Date: Tue, 25 Jan 2011 12:09:07 -0500
Message-ID: <4D3F03B3.6080606@nokia.com>
To: "public-webevents@w3.org" <public-webevents@w3.org>
The draft minutes from the January 25 voice conference are available at 
the following and copied below:

   http://www.w3.org/2011/01/25-webevents-minutes.html

WG Members - if you have any comments, corrections, etc., please send 
them to the public-webevents mail list before February 1 (the next voice 
conference); otherwise these minutes will be considered Approved as is.

-Art Barstow

    [1]W3C

       [1] http://www.w3.org/

                                - DRAFT -

                 Web Events Working Group Teleconference

25 Jan 2011

    [2]Agenda

       [2] http://lists.w3.org/Archives/Public/public-webevents/2011JanMar/0009.html

    See also: [3]IRC log

       [3] http://www.w3.org/2011/01/25-webevents-irc

Attendees

    Present
           Art_Barstow, Doug_Schepers, Laszlo_Gombos, Matt_Brubeck,
           Josh_Soref, Sangwhan_Moon

    Regrets
           Dzung_Tran, Anders_Höckersten, Olli_Pettay

    Chair
           Art

    Scribe
           Art

Contents

      * [4]Topics
          1. [5]Tweak Agenda
          2. [6]Touch Events spec
          3. [7]Any Other Business
      * [8]Summary of Action Items
      _________________________________________________________

    <trackbot>  Date: 25 January 2011

    <scribe>  ScribeNick: ArtB

    <scribe>  Scribe: Art

    Date: 25 January 2011

    <scribe>  Meeting: Web Events WG Voice Conference

    egrets: Dzung_Tran, Anders_Höckersten, Olli_Pettay

    <shepazu>  trackbot, start telcon

    <trackbot>  Meeting: Web Events Working Group Teleconference

    <trackbot>  Date: 25 January 2011

    <shepazu>  code: 9231#

    <shepazu>
    [9]http://www.w3.org/Guide/1998/08/teleconference-calendar#s_4378

       [9] http://www.w3.org/Guide/1998/08/teleconference-calendar#s_4378

Tweak Agenda

    AB: a draft agenda was submitted yesterday (
    [10]http://lists.w3.org/Archives/Public/public-webevents/2011JanMar/
    0009.html ). Any change requests?

      [10] http://lists.w3.org/Archives/Public/public-webevents/2011JanMar/0009.html

    [ None ]

Touch Events spec

    AB: earlier today, Doug announced the availability of the "Touch
    Events Specification" Editor's Draft (
    [11]http://dvcs.w3.org/hg/webevents/raw-file/tip/touchevents.html ).
    ... thanks Doug!

      [11] http://dvcs.w3.org/hg/webevents/raw-file/tip/touchevents.html

    <timeless_w7ip>  doug: congrats on getting Hg up :)

    AB: this is indeed a fresh doc, so I don't expect everyone to have
    read it
    ... and we do have some regrets

    DS: I'd like to go through it
    ... I'll start with an introduction
    ... I struggled a bit and then each event is a set of lists
    ... and each list is a set of touch points
    ... and each touch point has several attributes one would associate
    with an event
    ... f.ex., for a click, get screen x+ why
    ... in webkit get lists and those lists have the events
    ... took this pretty much from Webkit impl as documented on various
    sources on the web

    <mbrubeck>  useful for comparison:
    [12]http://developer.apple.com/library/safari/#documentation/UserExp
    erience/Reference/TouchEventClassReference/TouchEvent/TouchEvent.htm
    l

      [12] http://developer.apple.com/library/safari/#documentation/UserExperience/Reference/TouchEventClassReference/TouchEvent/TouchEvent.html

    DS: I did add some stuff: cx and cy
    ... I mean rx and ry

    <timeless_w7ip>  oh, good. i was going to complain about that (cx v.
    rx), i'd rather "radiusX"/"radiusY"

    DS: they indicate radius of the x+why
    ... need an area rather than an exact point
    ... so why did I use this model rather than the Mozilla model?
    ... I think the WebKit model has broader deployment
    ... Josh asked about the names I choose and about identifiers rather
    than an ID
    ... the answer is: that's the way it is done in WebKit

    AB: add, as a first ED, the contents are all up for discussion
    ... i.e. the spec isn't frozen :-)

    <timeless_w7ip>  indeed, there was a promise that we weren't going to
    treat first editor's content as final

    MB: I've done some work on Gecko and WK but work for Mozilla
    ... I submitted my comments

    DS: with balls and wheels have some stair-stepping problems
    ... may need to do some mapping
    ... for the 1st draft, I thought it would be easier to use WK model
    ... if there are good reasons to change, we should discuss that

    MB: the two main diffs between ED and WK impls are
    ... 1) touch radius
    ... and 2) touch enter and leave?

    DS: yes, that's correct

    LG: WK has keyboard modifiers on touch events

    DS: oh, I forgot to add them

    <timeless_w7ip>  shepazu: (editorial) i think you should probably add
    references to the WK and Gecko docs to the References section :)

    MB: it enherit from UIEvent

    DS: OK; good to know; I'll change that
    ... In my local copy, I changed to UIEvent
    ... will also add the keyboard stuff; should be easy to do
    ... re kebd modifiers, you are talking about Meta/Alt keys?

    MB: correct

    DS: is that in the touch point or the touch interface?
    ... should be in same place as screenX and screenY, right?

    MB: yes

    DS: ok, control key, meta key, ...; I'll copy those from DOM 3
    Events spec

    <mbrubeck>  Sangwhan_Moon1: are you on the call?

    AB: I noticed Sangwhan has a question but I don't think he is on the
    call

    <lgombos>  WebKit latest TouchEevent -
    [13]http://trac.webkit.org/browser/trunk/Source/WebCore/dom/TouchEve
    nt.idl

      [13] http://trac.webkit.org/browser/trunk/Source/WebCore/dom/TouchEvent.idl

    LG: the URI entered is a reference for the modifiers and events for
    WK impl

    <timeless_w7ip>
    [14]http://www.w3.org/TR/DOM-Level-2-Events/events.html#Events-Mouse
    Event

      [14] http://www.w3.org/TR/DOM-Level-2-Events/events.html#Events-MouseEvent

    <mbrubeck>  Safari uses "long" for screen events:
    [15]http://developer.apple.com/library/safari/#documentation/UserExp
    erience/Reference/TouchEventClassReference/TouchEvent/TouchEvent.htm
    l

      [15] http://developer.apple.com/library/safari/#documentation/UserExperience/Reference/TouchEventClassReference/TouchEvent/TouchEvent.html

    <timeless_w7ip>  the datatype issue is that events attributes like
    clientX are integer-ish not float-ish

    AB: any other comments Matt you want to raise now?

    <Sangwhan_Moon1>  I believe long would be a better option than using
    floats

    MB: a few minor things e.g. rx and ry attrs
    ... the spec should talk about the coordinate system

    DS: I've updated the text to use pixels

    MB: but pixels are ambigous

    <Sangwhan_Moon1>  as it is very unlikely that a float screen
    coordinate is possible in the real world

    MB: in that they are device dependent
    ... and used differently e.g. in CSS pixels

    <timeless_w7ip>  it should be in "input coordinates" consistent with
    how the mouse pixels work

    <Sangwhan_Moon1>  DOM 2 mouse events also uses long for screen
    coordinates

    MB: If content authors will use this data, they need to relate it to
    a physical size

    <Sangwhan_Moon1>  so it would make more sense to have those in align
    in terms of datatypes

    MB: and that would mean using something like CSS pixels

    DS: I'm ok with that
    ... but they are already assuming the same number of pixels from
    pageX, pageY, etc.

    MB: but those use different size pixels with mobile safari

    DS: screenX and screenY should be the same

    MB: true but pageX and pageY do change
    ... not clear if rX and rY would change
    ... if content authors want to map rX and rY to physical lengths
    ... they need to know the density of the display
    ... assuming they are in hw pixels rather than CSS pixels

    <timeless_w7ip>  ... which can be done perhaps w/ CSS media queries,
    which is "awkward"

    DS: we do need to define what we are using
    ... and reference something, probably CSS

    AB: we can't leave it open in the spec, right?

    MB: correct; we don't need to solve it today on this call

    <Zakim>  timeless_w7ip, you wanted to ask for changing "r" for
    "radius"

    JS: would prefer "radiusX" to be consistent with screenX, ...

    DS: that's fine with me (I'm biased by SVG)
    ... are people ok with touch area being an ellipse?

    MB: not clear what an impl should do if it doesn't have info about
    the area

    DS:<digress>this is the first time I've used respec; anyone else
    used it?
    ... not clear how NoExceptions is used

    MB: so it does not throw an exception?

    DS: I need to clarify this
    ... it is zero if no other value is available

    JS: 1 may be better because people will try to divide by 0 and
    indeterminate things happen then

    DS: I'm fine with using "1"

    <timeless_w7ip>  (technically they are rather well defined, but
    propogation is distressing to real users)

    LG: what if someone is not using a finger but something else

    DS: don't think that would be distinguishable
    ... can't distinguish between finger or stylus

    <shepazu>  updated:
    [16]http://dvcs.w3.org/hg/webevents/raw-file/tip/touchevents.html

      [16] http://dvcs.w3.org/hg/webevents/raw-file/tip/touchevents.html

    JS: need to be careful to not discriminate based on capabilities of
    users

    <timeless_w7ip>   [17]http://www.section508.gov ]

      [17] http://www.section508.gov/

    DS: this is about distinguishing different device capabilities (not
    user capabilities)
    ... oh, just realized I need to add pressure

    <mbrubeck>  Sangwhan_Moon1: no, it hasn't

    <mbrubeck>  Sangwhan_Moon1: agenda -
    [18]http://developer.apple.com/library/safari/#documentation/UserExp
    erience/Reference/TouchEventClassReference/TouchEvent/TouchEvent.htm
    l

      [18] http://developer.apple.com/library/safari/#documentation/UserExperience/Reference/TouchEventClassReference/TouchEvent/TouchEvent.html

    <mbrubeck>  wrong link

    DS: and I have checked in a new version

    <mbrubeck>
    [19]http://lists.w3.org/Archives/Public/public-webevents/2011JanMar/
    0009.html

      [19] http://lists.w3.org/Archives/Public/public-webevents/2011JanMar/0009.html

    DS: want to be flexibile on input devices

    <timeless_w7ip>  i fully expect each web application to butcher and
    mishandle various input methods

    DS: to be more explicit, would need to expose device capabilities
    ... eg: does this device expose pressure sensitivity

    <timeless_w7ip>  whereas, providing encouragement for user agents to
    provide a way for users to express strokes/pressure/whatever

    DS: does it undertand stylus with rX and rY
    ... then it adatation could be done based on feature detection

    <timeless_w7ip>  if a query by an web application allows a user agent
    to offer emulation to the user, then that might be ok

    DS: and not sniffing

    <lgombos>  shepazu: on the latest draft "readonly attribute boolean
    metaKey" is still missing

    DS: I don't know how to specify that UA may specify these things
    ... I can add lang that some features may not be supported and UA
    may do customizations

    JS: think the spec should encourage good behaviours

    DS: I would like a concrete example, please

    JS: I don't have anything to offer now

    DS: I would appreciate it Josh, if you would take this to the list

    <mbrubeck>  When specifying capabilities like touch radius that are
    not available to all devices/agents, the spec could say that these
    attributes could represent other user-controlled inputs, at the UA's
    discrection.

    MB: I want to talk about capture
    ... eg. which elements receive touch events
    ... in WK browsers, element that receives touch event

    <scribe>  ... continues to receive events even if the input has moved

    <timeless_w7ip>  [ matt believes that touchdown targets effectively
    are able to manage drag events because they continue to get events ]

    DS: yes, I believe that is true

    MB: this affects touch enter and leave events
    ... if have two simultaneous touch events on different elements,
    then which one gets event first?

    DS: wouldn't you throw 2 events?

    MB: or have one event with a list

    DS: I would expect 2 diff events
    ... and each event to have both touch points
    ... target touches get one touch point
    ... but in this case there would be two events each with 2 touches
    items, 2 changedTouches items, and 1 targetTouches item

    MB: regarding capture, think we need to review some existing impls
    ... re touch/cancel event
    ... the ED defines 1 narrow case
    ... would prefer to make that more impl defined
    ... if tracking stops before end, should be able to cancel

    DS: I'd like to define as many as we can
    ... e.g. must fire when X happens and may fire an event at other
    times ...
    ... re simultaneous touches
    ... do you think it would be useful to add a timestamp to each touch
    point?
    ... or, would that be useless overhead?
    ... May want to go thru a list to see when different touches
    happened

    <timeless_w7ip>  i'm pretty sure some dom events typically do have
    timestamps

    <timeless_w7ip>  so yes, i think it's vaguely useful

    MB: can't they track that info by watching touch up and down events?

    DS: yes

    MB: so, that would just be for convenience?

    DS: yes

    MB: ok, so I have no opinion

    <timeless_w7ip>  oh. this is to the touch point as opposed to the
    touch event? if the event contains the other, then i guess it seems
    superfluous..

    SM: preventing default behaviour from the UA

    DS: I haven't gotten around to that yet
    ... will try to get something into the spec before next call
    ... another question - regarding pressure ....
    ... what units should we use?

    <timeless_w7ip>  pressure is sometimes from 0..1

    DS: a scale of 1 to 10
    ... an unbounded float
    ... should it be relative?

    SM: most analog devices use 0 to 1

    DS: could be boolean :)

    <timeless_w7ip>  x11 exposes pressure

    SM: so far I haven't seen a platform that propagates pressue down to
    the app

    <timeless_w7ip>  and Qt iirc exposes it

    <timeless_w7ip>  you can get pressure from one of the major windows
    touchpad vendors if you talk to it

    DS: some support exists; can do it with flash

    <timeless_w7ip>  (synaptics)

    <timeless_w7ip>
    [20]http://docs.huihoo.com/qt/4.3/widgets-tablet-tabletcanvas-cpp.ht
    ml is an example of a pressure aware Qt app fwiw

      [20] http://docs.huihoo.com/qt/4.3/widgets-tablet-tabletcanvas-cpp.html

    AB: any other urgent questions? We have about 5 mins left
    ... anything else Doug?

    DS: I will probably look at InkML spec for related stuff

Any Other Business

    <timeless_w7ip>
    [21]http://doc.trolltech.com/4.5/qtabletevent.html#pressure uses
    0..1 fwiw

      [21] http://doc.trolltech.com/4.5/qtabletevent.html#pressure

    AB: naturally, we want technical discussions to continue on the list
    ... what about a call next week?

    <shepazu>  [22]http://www.w3.org/TR/InkML/

      [22] http://www.w3.org/TR/InkML/

    DS: I do intend to update the spec

    <mbrubeck>  if there were any platforms that use unbounded floats for
    pressure, it would be easy for UAs to normalize that to a 0..1
    range.

    DS: and we had a bunch of people that couldn't make it today

    AB: tentatively have a call next week and that would be Feb 1
    ... and it will be canceled if it there is no clear need to have it

    <timeless_w7ip>   [23]http://forum.chumby.com/viewtopic.php?id=4107
    -- XSPRawTouchscreenEvent ]

      [23] http://forum.chumby.com/viewtopic.php?id=4107

    AB: thanks again Doug!
    ... meeting adjourned

    RSSAgent, make minutes

Summary of Action Items

    [End of minutes]
Received on Tuesday, 25 January 2011 17:09:39 GMT

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