Minutes, 2 June 2016 SVG WG telcon

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Minutes, 2 June 2016 SVG WG telcon

Nikos Andronikos
Available at:

And as text,


      [1] http://www.w3.org/

                               - DRAFT -

                    SVG Working Group Teleconference

02 Jun 2016


      [2] https://lists.w3.org/Archives/Public/www-svg/2016Jun/0000.html

   See also: [3]IRC log

      [3] http://www.w3.org/2016/06/02-svg-irc


          nikos, AmeliaBR, shepazu, stakagi, Tav




     * [4]Topics
         1. [5]Switch and conditional processing issues
         2. [6]systemLanguage attribute
         3. [7]no title/desc in switch
         4. [8]Switch with non rendered (audio and visual )
         5. [9]removal of requiredFeatures
     * [10]Summary of Action Items
     * [11]Summary of Resolutions

   <stakagi> hello

   <scribe> scribe: Nikos

   <scribe> scribenick: nikos

Switch and conditional processing issues


     [12] https://github.com/w3c/svgwg/issues/138

   AmeliaBR: There's one issue as a summary, with lots of specific
   issues hanging off that

   <AmeliaBR> Summary: [13]https://github.com/w3c/svgwg/issues/139

     [13] https://github.com/w3c/svgwg/issues/139

   switch originally had three different attributes for
   controlling when you switch different features

   scribe: one is requiredExtensions, think the idea was that if
   somebody somewhere in some other spec or software defined an
   extension, then in svg we could define something that should
   only be rendered if that was supported
   ... it doesn't seem to be well used
   ... but some things would be useful to define
   ... like whether this svg ua can render html
   ... have a non standard extension in FireFox that takes the xml
   ... not defined in the standard anywhere, and not supported by
   other browsers
   ... think it would be useful to have some way of saying what
   type of documents this UA supports
   ... or suggest what type of image file can you embed?

   nikos: I think I'd like to defer this.
   ... can we put this in the integration spec?
   ... or another spec that's just a list of supported extensions?
   ... I'm supportive of capturing the extensions that are used by
   user agents so we can get interop

   shepazu: I thought integration spec too

   AmeliaBR: SVG 2 just defines the content as a url and doesn't
   have requirements beyond that

   RESOLUTION: SVG WG will list details of common extensions and
   supported values for the requiredExtensions attribute in the
   integration spec

   nikos: Would it be better to just support the picture element
   rather than image formats in switch?

   AmeliaBR: That's not as backwards compatible as switch
   ... right now, you could get an image if you used switch so you
   would get a sensible format

   shepazu: Is switch supported in illustrator or Inkscape?

   AmeliaBR: it's supported in rendering afaik but you can't
   generate it

   Tav: I'm not 100% sure, I know we parse it but not sure what we
   do with it
   ... think there are comments saying we should do something or
   other with it

   shepazu: When I think about SVG, there's a number of places, I
   think of authoring tools and browsers primarily
   ... there's other environments, but I don't expect they're
   using switch at all
   ... so when you say it's not supported, I think it would be
   trivial to do this in an svg + html context
   ... and since modern browsers support html5, I wonder what part
   of the ecosystem wouldn't support picture?

   AmeliaBR: it's not supported right now for svg

   Tav: not supported by Inkscape or Illustrator

   shepazu: I think if we are going to change behaviour, we should
   aim towards html rather than going alone

   AmeliaBR: it's also relevant to foreignObject, to define what
   time of content should be supported

   shepazu: my position is generally to not add new features or
   not extend less well supported features of SVG

   nikos: Agree

systemLanguage attribute

   <AmeliaBR> [14]https://github.com/w3c/svgwg/issues/136

     [14] https://github.com/w3c/svgwg/issues/136

   AmeliaBR: There's a bit of a limitation in how systemLanguage
   is defined
   ... assumes users only have one preferred language
   ... or that all options are equal
   ... this can be problematic if users have for example preferred
   languages, but will accept English if need be
   ... SMIL in later versions introduced an attribute that allows
   the user agent to be smarter
   ... hasn't been adopted into svg
   ... is supported in FireFox
   ... though there's HTML parsing issues because it's a mixed
   case attribute
   ... my pref is to spec so smart language matching is the
   ... and not worry about the attribute, because I don't see when
   you'd want the other behaviour

   nikos: I support this. Language choice is one of the more
   useful uses of switch
   ... it's defined already in another spec so we can just
   reference it
   ... are there any issues changing the default behaviour?

   AmeliaBR: are people leaning towards adding the reoder
   attribute? or define language matching?

   Tav: the latter

   AmeliaBR: In FireFox you have to specifically allow reorder,
   the default is the old behaviour

   shepazu: as long as we can get implementers, I like the second

   RESOLUTION: Language selection order for systemLanguage
   attribute will follow allowReorder=true by default

   <scribe> ACTION: shepazu to have a go at changing
   systemLanguage to allowReorder by default [recorded in

     [15] http://www.w3.org/2016/06/02-svg-minutes.html#action01]

   <trackbot> Created ACTION-3844 - Have a go at changing
   systemlanguage to allowreorder by default [on Doug Schepers -
   due 2016-06-09].

   shepazu: would be best to include inline rather than reference

no title/desc in switch

   AmeliaBR: think this is just editorial
   ... title and desc interfere with the selection of child
   elements so we resolved to remove them from the content model

Switch with non rendered (audio and visual ) content

   UNKNOWN_SPEAKER: There was a previous resolution that switch
   doesn't affect script and style
   ... we had an issue raised about how it interacts with audio
   and video
   ... my suggestion was that it should be treated as if audio and
   video are display:none
   ... which means the audio and video don't play

   nikos: I agree with that behaviour. Was trying to find where in
   HTML5 it says audio and video don't play on display none
   ... if anyone knows where that is, drop a link in the issue
   ... There was the question of whether resources should be
   loaded at all. But they probably have to, because they can be
   accessed through the DOM. It's like images that are

removal of requiredFeatures

   In SVG 1.1 we had requiredFeatures that had a defined list or
   category of features that svg would support

   scribe: that has been removed from SVG 2
   ... browsers implement it in a way where they didn't behave
   properly if you put in something that wasn't recognised
   ... I was wondering whether it might make sense to add back in
   as a deprecated feature
   ... so UA must support all SVG 11 strings

   nikos: was wondering if we should leave it in and define it as
   returning true

   AmeliaBR: that's the same as removing because of the behaviour
   defined in the spec.

   nikos: that's ok then, probably the reason why it was just
   removed. I say just leave it as is

   shepazu: I agree with that
   ... browser vendors in the past have always pushed back on
   conditional processing. Unless that has changed in the last
   couple of years, I don't see us getting momentum in the
   implementation so don't think we should put much effort in

   AmeliaBR: CSS conditional processing seems to be doing well,
   I'd love to build on that but not something we can do now

   shepazu: I tried to put something like this in dom3 events but
   was met with strong resistance
   ... they're not bad ideas, just need to focus on what we need
   to do to get SVG 2 done

   AmeliaBR: agree with new features, what do we do with existing
   features that are poorly implemented? How do we clean up the
   ... I have lots of ideas how to make switch cool with MQ and

   shepazu: If a feature was poorly implemented, it could be
   because it was poorly specced, it could be that it wasn't
   tested well, could be lack of browser interest
   ... we need to work out on a case by case basis which one it
   ... for switch, it never really passed the critical mass of
   implementers that it needed to succeed
   ... understand what you're saying about what do we do with
   what's left in the spec

   AmeliaBR: switch and requiredFeatures has two implementations
   unless it's been torn out in the last year
   ... problem is the feature strings aren't clearly defined
   ... testing for filter support for example didn't mean the
   feature was supported without bugs

   shepazu: that's why hasFeature fell by the wayside
   ... the fine grainedness was missing
   ... browsers don't want to implement that level of grain
   ... I say this as a person who strongly advocated for this in
   the past

   AmeliaBR: it might be useful to have a note in the conditional
   processing overview saying the requiredFeatures attribute has
   been removed

   <scribe> ACTION: Amelia to add a note regarding removal of
   requiredFeatures [recorded in

     [16] http://www.w3.org/2016/06/02-svg-minutes.html#action02]

   <trackbot> Created ACTION-3845 - Add a note regarding removal
   of requiredfeatures [on Amelia Bellamy-Royds - due 2016-06-09].

Summary of Action Items

   [NEW] ACTION: Amelia to add a note regarding removal of
   requiredFeatures [recorded in
   [NEW] ACTION: shepazu to have a go at changing systemLanguage
   to allowReorder by default [recorded in

     [17] http://www.w3.org/2016/06/02-svg-minutes.html#action02
     [18] http://www.w3.org/2016/06/02-svg-minutes.html#action01

Summary of Resolutions

    1. [19]SVG WG will list details of common extensions and
       supported values for the requiredExtensions attribute in
       the integration spec
    2. [20]Language selection order for systemLanguage attribute
       will follow allowReorder=true by default

   [End of minutes]

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