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minutes, 18 August 2011 SVG WG telcon

From: Cameron McCormack <cam@mcc.id.au>
Date: Fri, 19 Aug 2011 09:34:23 +1200
Message-ID: <4E4D855F.8070003@mcc.id.au>
To: 'www-svg' <www-svg@w3.org>
Please find minutes from today's SVG WG telcon at 
http://www.w3.org/2011/08/18-svg-minutes.html and below as text.


    [1]W3C

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

                                - DRAFT -

                    SVG Working Group Teleconference

18 Aug 2011

    [2]Agenda

       [2] 
http://lists.w3.org/Archives/Public/public-svg-wg/2011JulSep/0111.html

    See also: [3]IRC log

       [3] http://www.w3.org/2011/08/18-svg-irc

Attendees

    Present
           heycam, Doug_Schepers, +1.317.506.aaaa, cyril, ed

    Regrets
    Chair
           Cameron

    Scribe
           Cyril Concolato, Cameron

Contents

      * [4]Topics
          1. [5]meeting plan around SVG Open and TPAC
          2. [6]Feature request list for SVG 2
          3. [7]radial gradients
          4. [8]propagation of events
          5. [9]text tracks and webvtt
      * [10]Summary of Action Items
      _________________________________________________________

    <trackbot> Date: 18 August 2011

    <cyril> thanks heycam

    <cyril> heycam, how do you generate the ToC on the group's wiki
    pages ?

    <heycam> cyril, you just use headings like "= Level 1 heading =" or
    "== blah blah Level 2 heading =="

    <cyril> thank you

    <cyril> I'll edit the SVG 1.2 Tiny page

    <cyril> it's easier to reference to a item by number

    <cyril> yes

    <cyril> scribe: Cyril Concolato

    <cyril> scribenick: cyril

meeting plan around SVG Open and TPAC

    CM: we decided not to have an SVG F2F WG meeting in SVG Open but Tav
    can only be there

    DS: having a day is reasonnable

    CM: it doesn't even have to be a whole day
    ... it depends on the topic
    ... it would be nice to have Tav because he's usually not able to
    travel
    ... we can have a meeting and review what was discussed later on in
    Santa Clara

    ED: what day ?

    CM: are you involved in the workshop day ? on the thursday ?
    ... Tav is not involved in the workshops
    ... I'm wondering about rooms
    ... it would be good to meet in the same place as the workshops

    CC: could we have a bridge to call in ?

    CM: someone should contact the organizer to check room and bridge

    ED: the 4th day should be fine

    <scribe> ACTION: heycam to contact Andreas Neumann about the room
    and bridge for a short 1 day F2F at SVG Open 2011 [recorded in
    [11]http://www.w3.org/2011/08/18-svg-minutes.html#action01]

    <trackbot> Created ACTION-3109 - Contact Andreas Neumann about the
    room and bridge for a short 1 day F2F at SVG Open 2011 [on Cameron
    McCormack - due 2011-08-25].

Feature request list for SVG 2

    CM: we have 3 lists on the wiki

    <heycam>
    [12]http://www.w3.org/Graphics/SVG/WG/wiki/SVG2_Planning_Page

      [12] http://www.w3.org/Graphics/SVG/WG/wiki/SVG2_Planning_Page

    CM: we should discuss how we decide on those lists
    ... especially before the F2F
    ... we should put comments on the wiki
    ... it would be good if people could put comments on each feature
    and put a yes/no

    ED: I have an action to go through minutes for resolutions
    ... I'm not sure about overlaps

    CC: we should have a single list

    DS: agree, we should also quantify
    ... putting a numerical value 1-5
    ... one for priority
    ... one for complexity

    <ed> ACTION-3095?

    <trackbot> ACTION-3095 -- Erik Dahlström to go through the last few
    f2f minutes to find resolutions for SVG2 items, and add them to the
    wiki page. -- due 2011-08-05 -- OPEN

    <trackbot> [13]http://www.w3.org/Graphics/SVG/WG/track/actions/3095

      [13] http://www.w3.org/Graphics/SVG/WG/track/actions/3095

    DS: one for usefulness
    ... those are the 3 key factors
    ... obviously complexity is for viewers, but it might be also for
    authors but we can work that out in the text

    CM: should one of us go through all and put initial numbers

    DS: we can each contribute and then we discuss where we will not
    agree

    CM: would like to put those assessment done before you put your
    comments ?

    DS: not necessarily
    ... we should start today to put assessments

    CM: I think my 2 lists should be free of duplicates
    ... Issues are vague, coming from the tracker

    range from bug to feature

    scribe: I did not include bugs or problems with existing features

    <heycam>
    [14]http://www.w3.org/Graphics/SVG/WG/wiki/SVG2_Requirements_Input_F
    rom_Tracker

      [14] 
http://www.w3.org/Graphics/SVG/WG/wiki/SVG2_Requirements_Input_From_Tracker

    scribe: it would be nice to have the issue in a single list

    CM: is it reasonnable to go through the list for next week ?

    <scribe> ACTION: heycam to merge the two features/issues lists
    [recorded in
    [15]http://www.w3.org/2011/08/18-svg-minutes.html#action02]

    <trackbot> Created ACTION-3110 - Merge the two features/issues lists
    [on Cameron McCormack - due 2011-08-25].

    <scribe> ACTION: cyril to merge the SVG Tiny 1.2 features into the
    results of ACTION-3110 [recorded in
    [16]http://www.w3.org/2011/08/18-svg-minutes.html#action03]

    <trackbot> Created ACTION-3111 - Merge the SVG Tiny 1.2 features
    into the results of ACTION-3110 [on Cyril Concolato - due
    2011-08-25].

    CM: I'll put a template also to enable people to comment
    ... what about "Feedback from Jonathan Watt:
    [17]https://wiki.mozilla.org/SVG:Language:Regrets"

      [17] https://wiki.mozilla.org/SVG:Language:Regrets

    ED: I wonder how many are already covered by issues ...

    CM: at least one of those is already there (xlink)

    <scribe> ACTION: heycam to go through jwatt's SVG regret page and
    add any feature from there to our requirements wiki page [recorded
    in [18]http://www.w3.org/2011/08/18-svg-minutes.html#action04]

    <trackbot> Created ACTION-3112 - Go through jwatt's SVG regret page
    and add any feature from there to our requirements wiki page [on
    Cameron McCormack - due 2011-08-25].

    <heycam>
    [19]http://www.w3.org/Graphics/SVG/WG/wiki/SVG2_Requirements_Mailing
    _List_Feedback

      [19] 
http://www.w3.org/Graphics/SVG/WG/wiki/SVG2_Requirements_Mailing_List_Feedback

    CM: it's probably hard to accept something without a concrete
    proposal

    CC: we shouldn't definitely reject features without concrete
    proposal
    ... we should give an idea if a proposal in a given area is
    acceptable to the group or not

    <heycam> ScribeNick: heycam

    <scribe> Scribe: Cameron

radial gradients

    CC: this is related to an action erik has

    ACTION-3097?

    <trackbot> ACTION-3097 -- Erik Dahlström to propose wording for the
    edge case where a radialGradient's focal point sits on the edge of
    the circle and the gradient repeats. the spec. should say that when
    the focal point is on the circle edge, with repeat, then the
    distance between the first and last stop for the repeating colors is
    0 and the paint should generate a color that is the average of all
    the gradient stops. -- due 2011-08-05 -- OPEN

    <trackbot> [20]http://www.w3.org/Graphics/SVG/WG/track/actions/3097

      [20] http://www.w3.org/Graphics/SVG/WG/track/actions/3097

    CC: In seattle we discussed content that has radial gradient
    noninteroperable behaviour
    ... I tried to check with the spec what the problem was
    ... if the spec was actually specifying something about the
    behaviour of the gradient outside of the circle, but there's no
    formula for how the gradient should be built
    ... I only found one in the canvas spec

    [21]http://lists.w3.org/Archives/Public/public-svg-wg/2011JulSep/009
    5.html

      [21] 
http://lists.w3.org/Archives/Public/public-svg-wg/2011JulSep/0095.html

    scribe: so in the canvas spec it clearly defines how to build the
    gradient
    ... but it doesn't say what to do when the centre of the circle is
    outside the main circle

    ED: canvas doesn't have reflect and repeat

    CC: I think as a basis we could adopt this definition for the inside
    of the circle
    ... it would clarify how we build the gradient
    ... then we should define how we fill the outside the circle
    ... in the email I have two examples

    <cyril>
    [22]http://perso.telecom-paristech.fr/~concolat/SVG/radial_gradient_
    construction_animation.svg

      [22] 
http://perso.telecom-paristech.fr/~concolat/SVG/radial_gradient_construction_animation.svg

    CC: that shows a radialGradient with a repeat
    ... it shows that if you continue the formula defined in the canvas
    spec, you don't have a problem, the gradient is well defined

    <cyril>
    [23]http://perso.telecom-paristech.fr/~concolat/SVG/radial_gradient_
    construction_animation_edge_case.svg

      [23] 
http://perso.telecom-paristech.fr/~concolat/SVG/radial_gradient_construction_animation_edge_case.svg

    CC: in this one the focal point is on the edge of the circle
    defining the gradient
    ... you can still follow the canvas spec formula, but it only fills
    half the plane
    ... as you animate the circle you'll never go beyond the normal to
    the focal point

    CM: so that'd be a straight vertical line

    <krit> Firefox and WebKit don't support setting focal point on the
    edge

    CM: for reflect we could just mirror the image around that line
    ... we could just define this not to work

    CC: or choose a solid colour to fill the rest of the plane with

    ED: I think IE does this

    CC: I'm just checking IE9, they don't use a solid colour

    CM: so I think it would be good for us to have a formula for
    computing gradient colors

    CC: the one in the canvas spec is the one that we want

    ED: the action I have is to make the half plane fill with a solid
    colour, average of all the stops in the gradient

    CC: I don't understand why though
    ... it's not even a colour that the author specified
    ... I could understand the colour at stop 0 or 1, but why the
    average?

    ED: probably because it's hard to pick any colour that matches

    CM: I think Tab was using average of stop colours in certain cases
    in css3 image values, but I don't remember which cases they were

    ED: if you have a line perpendicular to the radius of the circle,
    and keep very tiny steps between each straight line, you'll get
    something like an average
    ... tightly packed colours from the gradient

    CM: we could flip the well defined half of the image to the
    undefined part

    ED: it seems like new behaviour though

    CM: does it make sense as a "reflect" or "repeat"?

    ED: not so much repeat, reflect yes. it's different from the linear
    gradient though.

    CC: another point was talking about a new value, a smaller radius
    fr=""
    ... I think we can already do it by adding an initial stop colour
    ... same offset colour for 0 and fr/r
    ... then you get the same effect

    CM: unless you want to repeat/reflect into that smaller circle

    CC: the pdf spec has an fr

    <cyril> Figure L.11

    CC: they have some interesting examples

    <cyril>
    [24]http://wwwimages.adobe.com/www.adobe.com/content/dam/Adobe/en/de
    vnet/pdf/pdfs/PDF32000_2008.pdf

      [24] 
http://wwwimages.adobe.com/www.adobe.com/content/dam/Adobe/en/devnet/pdf/pdfs/PDF32000_2008.pdf

    CM: ok so they don't fill anything in the inner circle

    CC: let's see what erik proposes
    ... the adobe guys might have an opinion

    ED: the canvas one, does that support things outside the circle?

    CC: no

    ED: I will consider this when making the proposal

propagation of events

    [25]http://lists.w3.org/Archives/Public/public-svg-wg/2011JulSep/008
    5.html

      [25] 
http://lists.w3.org/Archives/Public/public-svg-wg/2011JulSep/0085.html

    CC: I don't know if you understood my problem
    ... I think this is applicable to 1.1
    ... when you have an SVG linked from another SVG, two separate
    documents
    ... this describes a single application
    ... you want some key events to be processed by the parent document,
    and some by the child document
    ... you want to design your documents so they don't know exactly
    what the other document is doing with the keys
    ... e.g. if the subdocument has the focus, and you press "a", if
    it's used by the subdocument it's fine, if not then it could go to
    the parent document
    ... a bit like mouse events -- when you click on the subdocument and
    there's nothing to be clicked on, transparent background, then the
    parent document will take that event

    CM: I think they're slightly different cases
    ... I'm thinking about iframes, events don't propagate across those

    CC: what do inner documents do with a key that's not been used?
    ... I'd like some text to describe that

    [discussion of animation vs image]

    ED: I would expect svg <image> to behave the same as html <img>

    CC: the question then is how should it work with an iframe
    ... I'll make some tests

    CM: if we wanted to allow propagation across windows, it's broader
    than just svg

    CC: yes it's more of platform thing than just svg

    CM: I think it is defined that it shouldn't propagate currently
    ... per dom events flow

text tracks and webvtt

    CC: I was arguing that you could do the same thing in SVG, with
    synchronised graphics
    ... I wanted to check whether there was any interest in having
    synchronised graphics in this context
    ... I found a page from Charles on how to do subtitling in SVG in
    Opera

    s/Chaals/Chaal/s

    <cyril> [26]http://dev.opera.com/forums/topic/370891

      [26] http://dev.opera.com/forums/topic/370891

    CC: This is a year and a half old example
    ... sylvia was saying that browsers will implement webvtt, and not
    svg as tracks

    ED: webvtt is probably a lot simpler to write

    CC: yes but it's more limited
    ... my guess, since it's how we implemented in gpac, is that once
    you have svg and video support, adding synchronised display of svg
    on top of video is not complex

    CM: does webvtt fire events?

    <krit> it does

    CC: ontrackcuechange

    CM: so maybe you could have svg animation triggered off those

    CC: all you need is to use the same time base as the video
    ... don't even need the events
    ... see the example from chaals
    ... you can structure your svg file in a way that is frame based,
    it's really equivalent to a vtt file
    ... one use case is having clickable shapes that come up
    ... with a link to a web page for an advertisement for example
    ... the media pipeline taskforce are only considering rectangular
    regions

    <cyril>
    [27]http://lists.w3.org/Archives/Public/public-web-and-tv/2011Aug/00
    23.html

      [27] 
http://lists.w3.org/Archives/Public/public-web-and-tv/2011Aug/0023.html

    CM: one question would be whether to use the time of the video to
    drive smil animations in an svg document, or just to use webvtt cue
    times to show/hide svg fragments

    <cyril>
    [28]http://www.w3.org/TR/html5/video.html#handler-texttrackcue-onent
    er

      [28] 
http://www.w3.org/TR/html5/video.html#handler-texttrackcue-onenter

    CC: that's the actual events for the cues

    DS: I agree with cyril that there should be non-rectangular regions

    CC: how about the timing?

    DS: no opinion

    CC: silvia was mentioning another option would be to embed svg
    content in the webvtt file, and retrieve the svg from the cue event,
    put that svg inside the html document by script
    ... that would work, but it's a bit complicated
    ... if there is any interest in this, we can discuss this
Received on Thursday, 18 August 2011 21:35:00 GMT

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