Linköping F2F day 4 -- 12 Jun 2015

<scribe> Scribe: Cameron

<scribe> ScribeNick: heycam

Whether writing-mode should have a presentation attribute

heycam: adding a presentation attribute would violate our rule of not adding any new presentation attributes

Tav: I think it should have one

krit: it shouldn't be a problem implementation wise

ed: I would prefer having it, for consistency

heycam: text-orientation is the third one that works together with direction and writing-mode

Tav: add that too then
... we treat everything as presentation attribtues anyway

krit: for us it's a white list so we would need to add these things to a list

heycam: a middle point would be to add presentation attributes for all properties that have an effect on SVG elements
... but we'd need to go through all properties to decide

Rossen: I would prefer not having presentation attribute for witing-mode
... if we have a white list of allowed presentation attributes, I'd like that to be defined in an automated way
... so that if CSS gains new properties we don't need to update the list of presentation attributes
... doing one off things seems random, but having all properties as presentation attributes seems like overkill

Tav: we need something in the spec now

heycam: yes I plan to add a list to the Styling chapter

<scribe> ACTION: Cameron to present a few different ways of defining the list of presentation attributes to support [recorded in http://www.w3.org/2015/06/12-svg-minutes.html#action01]

<trackbot> Created ACTION-3806 - Present a few different ways of defining the list of presentation attributes to support [on Cameron McCormack - due 2015-06-19].

shadow trees on text content elements and text positioning attributes

heycam: we had a bug filed with something putting x and y attributes on a text and a shadow tree on a tspan
... do the x and y attributes apply to the shadow tree contents?

ed: was there a test case?

heycam: can't find the test right now

ed: don't know how blink would deal with this
... you could also put the text positioning attributes on shadow tree contents

heycam: maybe that argues for assigning the x/y to the shadow tree characters

Tav: you do have take the shadow tree contents into account when say text-anchor:middle centering
... would there be a place where you replace the content?
... I guess we just have to define a default behaviour and let the user figure it out

heycam: OK I will make the x/y apply to characters in the shadow tree as I write up the text layout algorithm

<scribe> ACTION: Cameron to attempt to make text positioning attributes apply to shadow tree content [recorded in http://www.w3.org/2015/06/12-svg-minutes.html#action02]

<trackbot> Created ACTION-3807 - Attempt to make text positioning attributes apply to shadow tree content [on Cameron McCormack - due 2015-06-19].

how textPath works with path seg lists

ed: SVG 2 has added a d attribute to textPath
... previously you could only link to a path
... and I think the spec currently says that if you have both href and d that it picks the d
... it's implementing SVGAnimatedPathData now too, which is where the pathSegList accessors are
... the spec says that if you href to a path, it should be exposed through those APIs
... and I don't think that's a good idea
... if you really want the other path element that defines the textPath, you can just go grab that
... and use the same methods there
... instead of trying to make some magic here
... so I think textPath should only return the d attribute and nothing else

heycam: I agree

nikos: yep

Tav: sounds good

RESOLUTION: pathSegList on textPath should only reflect the d attribute, not the href'ed path

<ed> https://svgwg.org/svg2-draft/text.html#TextPathElementDAttribute

<scribe> ACTION: Erik to make pathSegList on textPath only reflect the d attribute, not the href'ed path [recorded in http://www.w3.org/2015/06/12-svg-minutes.html#action03]

<trackbot> Created ACTION-3808 - Make pathseglist on textpath only reflect the d attribute, not the href'ed path [on Erik Dahlström - due 2015-06-19].

adding pathLength to textPath

ed: if you link to a path, then that path can have pathLength
... not sure if we have other cases where we have d attributes and pathLength?

krit: is it really required to have pathLength on path?

ed: it's not required, just asking if we should have it
... if you want, you can link to a path element, and that works

krit: yes, if you want it, you can do that
... I wouldn't add it

Tav: if you want to align something exactly you can always reference a <path>

RESOLUTION: We won't add pathLength to <textPath>

Add x/y/dx/dy to textPath

Tav: if we're not adding the others, no reason to add this

ed: I thought it was already possible to do this?

heycam: you can put them on a parent tspan, and it has the expected effect, but you can't have them on the textPath

Tav: you can already do this effect on tspan parent, so just leave it at that

heycam: I agree. let's not try to improve these text positioning attributes any more.

RESOLUTION: We won't add text positioning attributes to textPath

transform-origin on SVG elements

https://lists.w3.org/Archives/Public/www-style/2015Jun/0109.html

heycam: that's my proposed spec wording to handle this -- using a UA style rule

krit: so for SVG elements you'll get a default value of 0 0

heycam: for non-outer-<svg> SVG elements

krit: WebKit and Blink already use UA style rules to do this
... our rules might not be fully correct
... the one that Cameron posted should be OK

Rossen: and leave the initial value as it is?

heycam: yes

Rossen: the other way to do this is auto
... which is the usual way the CSS WG handles this kind of thing

heycam: I don't mind auto either

Rossen: we'll discuss this in CSS

Impact of CSS Transforms Level 2 on SVG

ed: there's some implementation work going on in Blink for this

krit: the Transforms 2 spec just adds the rotate, translate, scale properties and defines how they interact with transform

ed: right now the spec says that percentages are resolved according to the containing block, is that what we want in SVG?

krit: border box in SVG is complicated
... we have the transform-box property which lets you switch between bounding box and viewport

ed: doesn't say anything about that here

krit: that's in Transforms 1

ed: whether or not these properties should be made presentation attributes, too
... rotate would clash with rotate on text

krit: transform and transform-origin are presentation attributes

heycam: I don't think we support transform-origin as a presentation attribute

krit: but in WebKit/Blink we do
... I do not expect any problems with SVG here
... it's a good question to ask whether to make these presentation attributes

Tav: if you have transform and rotate? ti's determined what happens?

krit: yes, the order is fixed
... rotate is always applied before transform

heycam: I would say don't add presentation attributes for these right now
... and otherwise I don't think any other SVG considerations apply

definitions in Transforms Level 1

heycam: I spoke with takagi-san yesterday about this
... he has prepared some diffs to the Transforms spec for the definitions needed for reference
... he has prepared some diffs to the Transforms spec for the definitions needed for reference from the non-scaling features of SVG
... he wanted to know whether they should go in Transforms Level 1 or 2

krit: it should be 2

heycam: I suggest then to email Tab with the definitions, and a reminder of the discussions we had in Sydney, and he can add them to that spec
... then we can reference them from SVG

http://svg2.mbsrv.net/devinfo/devstd/CSS_Transforms_Diff/

Tav: there's an issue with preserve-3d in there
... suppose you have a box, you rotate the box, the vector-effect would make each of those sides the same, you flatten it, you can't do anything after that

krit: there is a term in the spec for applying effects until the point that you flatten
... vector-effect is not intended for use with 3D transforms

SVGTransformList

<krit> file:///Users/dschulze/Documents/svgwg/build/publish/coords.html#InterfaceSVGAnimatedTransformList

krit: I added a bit of normative text to SVGAnimatedTransformList

<krit> https://svgwg.org/svg2-draft/coords.html#InterfaceSVGAnimatedTransformList

krit: we have the transform animVal and baseVal
... for the transfom attribute
... now that we have the transform property, the question is what do you get if you get/set baseVal
... what I wrote here is that the SVGTransformList always just reflects the attribute
... not the style value

heycam: we discussed this before and that's the behaviour we agreed on

-- fika --

Coordinates chapter

krit: in this chapter we have some definitions that need updates
... the first is "canvas", which says there's a physical space with a virtual infinite bounds that things can be drawn on
... and "SVG canvas" is an instance of "canvas"
... but that definition doesn't add any value
... the problem here is really "SVG viewport"

"The viewport within the SVG canvas which defines the rectangular region into which SVG content is rendered. See the discussion of the SVG viewport in the chapter on Coordinate Systems, Transformations and Units."

scribe: which implies the content is clipped to the bounds
... especially if you have overflow visible, that's not the case
... the question is how do we define "SVG viewport" and what does it do
... as in CSS, it's something like a containing block, that is a reference for sizing some content

Rossen: can't you define it as a rectangle for clipping if overflow is set appropriately

krit: there's also another definition "initial clip path"

Rossen: that's pretty much your viewport then

nikos: what about the rectangular region that maps to the view box

krit: vice versa

nikos: it's just defining that space

krit: the change to make across the spec is to only use "SVG viewport", not "viewport"
... if you define viewport as a boundary, that can be used for clipping if overflow:hidden, or gives the boundaries for overflow:scroll
... it's the rectangle viewBox is mapped to
... and it's the box that percentages are resolved against
... is that something we can agree on?

Rossen: does need to be rectangular?

krit: that's the current definition

Rossen: currently

krit: so currently it has to have width/height
... so I would define it as a rectangular boundary

Rossen: at some point we're going to have to deal with round displays

krit: right. that would still, even for round displays, have an a width/height extent

nikos: round with a different coordinate system?

krit: CSS WG is talking about that, with polar coordinates; just for positioning

nikos: so the polar coordinates just map to a position

krit: yes, still a cartesian coordinate system
... but positions are mapped from polar coordinates
... any objection to remove the term "canvas"?

nikos: there are a lot of areas in the spec where you want to say something that you're rendering on to

Tav: and to make it clear that it extends infinitely

krit: do we need this reference to physical media and computer memory?

nikos: make it more abstract than that

krit: the spec generally only references canvas and viewport, not SVG canvas and SVG viewport
... I think the idea here was to have ad istinction between host rendering and SVG rendering, but nowadays that doesn't matter

nikos: wasn't to distinguish from HTML <canvas>?

heycam: no that was before this text was written

Rossen: other specs doesn't reference SVG canvas

krit: the SVG viewport defines initial clipping for overflow property
... do I need to mention specific values of overflow?

Rossen: no

krit: then we have a definition of viewport coordinate system and user coordinate system
... and that viewport space = viewport coordinate system, and user space = user coordinate system
... we should just have single terms for these things
... the Transforms spec uses "local coordinate system", which I'd actually prefer

ed: is there a difference?

krit: no

ed: I'd prefer local too, then

Tav: the term "user units" is used a lot everywhere
... there's a history of using that term, even outside the spec

krit: would you suggest Erik replacing all user * things with local *?

ed: user sounds custom, local coordinate system sounds pretty clear

nikos: local is generally the term that's used, I think

krit: can we agree to change?

nikos: I agree in theory but we do have keywords like userSpaceOnUse

krit: CSS transforms already defines user coordinate system = local coordinate system
... there is some wording about establishing viewports and the "viewport coordinate system"
... for me, that's redundant, you map the coordinate system between parents and children

Tav: aren't percentages are in terms of viewport coordinate system?
... throughout the spec if you say percentages of the viewport, you don't need the term "viewport coordinate system"

krit: my guess is that it wants to distinguish between transforms that apply to content, and transforms that apply to the host document

Tav: is that term used anywhere else in the document?

krit: yes, introduction, painting, coords

nikos: in the vector-effects section, you could just say nested viewports couldn't you

krit: I'll work something out for that section and propose it
... next, the Initial coordinate system
... it says there is a viewport coordinate system and a user coordinate system and they are initially identical, and origin is at the top left
... not sure if this should be part of the rendering chapter, or to keep it here
... these definitions could do with some trimming

nikos: I think it makes sense to have it there

krit: I'd still like to reduce the text, it's a bit verbose
... and now, the "initial viewport"
... we have a few use cases of SVG, as a root document, or embedded, or inline, ...
... all these scenarios need to be specified somehow
... didn't find what viewport units means for a root document
... if width/height are auto, we don't have intrinsic size/ratio
... what's the size of the viewport then. usually it's the size of the window, right?
... which brings us to the initial of not defining what the initial containing block is
... vw and vh units need that to resolve against
... the containing block is usually the size of the window, when you test it
... how does CSS define the size of the ICB?

Rossen: it's defined as the first fragment, whether it's a page in a print media, or the size of the window, in a continuous media
... we can just refer to the same things as CSS
... I think it's section 9.5 or something
... the initial value of width/height properties are auto, which will resolve to 100% of the ICB

krit: when we have intrinsic ratio, and no sizing, that would also resolve against the ICB, yes?

Rossen: yes

krit: if you have intrinsic sizing, then the viewport would definted by the intrinsic sizing, which is not necessarily the same size as the ICB
... now, we come to the section about embedding SVG content
... the "establishing an ew SVG viewport" section, and "intrinsic sizing properties" section, which both try to define this but fail
... I would keep "establishing a new SVG viewport', which just says which elements do that
... "initial viewport" should reference an algorithm we define in the "intrinsic sizing properties" section
... plus of course everything for the root SVG, in case of not being hosted in a document

ed: because it's duplicated information?

krit: at the moment, embedded content is defined in multiple places
... I just want to put all the sizing information in the one place
... now, for embedding
... we had the presentation from David Vest in Leipzig
... which I won't go through now
... it's pretty simple generally
... you always have the containing block, which defines the sizing (or not) depending on the value of width/height on the root

[shows some examples]

krit: if you have an intrisic ratio, but no width/height, what should happen?
... it falls back to the replaced element algorithm?

Tav: can you work offline with Rossen on this?

krit: sure

pAR defer

http://mcc.id.au/temp/defer.svg

heycam: so in Edge, defer is not supported, in Firefox it is, in Blink the effect is basically "always defer"
... i.e. pAR on <image> is ignored when referencing an SVG image

krit: if you have an image with pAR on it, Blink and WebKit would follow it, but not the overriding one on the <image>

ed: I think defer is kind of useless

krit: I think the whole negotiation process is useless

ed: defer is ignored in all pARs other than on <image>

<ed> https://svgwg.org/svg2-draft/coords.html#PreserveAspectRatioAttribute

heycam: removing defer altogether, and making it a parse error, is probably safe

ed: I agree

krit: I don't care, removing it or not

ed: the bug fixes that would be needed are unrelated to defer

RESOLUTION: We will refer the defer keyword from pAR; encountering it would be a parse error.

<scribe> ACTION: Cameron to remove pAR's defer keyword. [recorded in http://www.w3.org/2015/06/12-svg-minutes.html#action04]

<trackbot> Created ACTION-3809 - Remove par's defer keyword. [on Cameron McCormack - due 2015-06-19].

blending with backdrop of multiple fill/stroke

krit: I looked at what photoshop, illustrator, and some other tools are doing
... they support multiple fills and strokes, they will be drawn on top of each other
... can also support a blend mode
... but they also blend with the backdrop
... where we said we would isolate them
... so I would suggest that we remove this isolation requirement

Tav: how does that work?
... render the second blended with the backdrop that already has the first fill blended into it?
... and if you isolate it?

nikos: then you only blend among the fills
... if you specify opacity on the shape at all, it will become isolated

krit: yes normal isolation requirements apply

nikos: is there a way to control the isolation within the fills?

krit: no

<krit> Rossen: http://dev.w3.org/fxtf/compositing-1/#csscompositingrules_CSS

RESOLUTION: Multiple fills and strokes are not isolated; they are all blended with the backdrop

<scribe> ACTION: Dirk to update the Painting chapter about multiple fills/strokes not isolating [recorded in http://www.w3.org/2015/06/12-svg-minutes.html#action05]

<trackbot> Created ACTION-3810 - Update the painting chapter about multiple fills/strokes not isolating [on Dirk Schulze - due 2015-06-19].

publishing another WD of SVG 2

heycam: let's publish another WD after this week of edits

all: ok

RESOLUTION: Publish a new WD of SVG 2 next week

<scribe> ACTION: Cameron to organise another SVG 2 WD publication [recorded in http://www.w3.org/2015/06/12-svg-minutes.html#action06]

<trackbot> Created ACTION-3811 - Organise another svg 2 wd publication [on Cameron McCormack - due 2015-06-19].

F2F planning

ed: Google are hosting CSS in Sydney
... they asked us whether we would like to meet there too

Rossen: there will most likely be a Houdini meeting next to it
... the feedback from the CSS WG that's worth pulling forward is that there were a number of members found travelling to Australia expensive
... especially those travelling on smaller (or their own) budget
... that was the one pushback
... Shane as one of the organizers put a number of hotels in the planning wiki
... it's worth looking and booking in advance, especially for hotels

nikos: we were thinking that if you were coming to Sydney, we'd (Canon) would offer too
... but Shane got in first
... I don't know how convenient that would be if people are already going to Google
... our office which is a 20 minutes train ride out of the city

Rossen: unless Google has a problem to host this for the extra couple of SVG days, I don't see why we'd change location
... it's very nice of you to offer
... but since they have offered, and we are already there

krit: are the dates fixed already?

Rossen: we at least resolved on the week

<Rossen> https://wiki.csswg.org/planning/sydney-2016

Feb 1-5

heycam: so SVG would be just before or after the weekend around that

Rossen: would prefer to meet on the weekend, to avoid extending the trip further

so either Jan 30-31, or Feb 6-7

depend on which end of the week houdini is meeting

Tav: would prefer a third SVG meeting day
... to make it worthwhile coming

RESOLUTION: Tentative resolution that we meet for 3 days either right before or right after the CSS/Houdini meetings in Sydney

Upcoming TPAC meeting

ed: unless I have some funding I probably won't come

Tav: I'm definitely not going
... as it'd only be a day and a half of SVG, based on prior experience, everyone's tired by the end of Friday

<shane> Houdini Jan 30-31 I think.

heycam: I probably can't come now

krit: I won't be there

Rossen: so without the chairs, and half of the regulars not there

ed: do we want to have a meeting somewhere/somewhen else?

Tav: another option could be Paris, after CSS

Rossen: for me that's a hard no
... I've got CSS, Houdini, then vacation
... which is already planned
... this time CSS is meeting Tue-Thu, not sure why that is, then Houdini is Fri/Sat

<Rossen> https://wiki.csswg.org/planning

Rossen: so Aug 25-27, followed by Houdini 28-29

krit: I will be at both of those
... I could attend an SVG meeting before then
... first, the Australians/Japanese, would you be able to attend?

stakagi_: for me no problem

ed: could also do Pittsburgh? though there would be more people in Paris.

nikos: I couldn't get there before 25th

krit: I couldn't go to Pittsburgh, as I have to fly to the US two weeks later

Rossen: we could organise something in Seattle?

krit: my trip might not be flexible
... so in Paris would be Aug 22-24?

ed: I'm booked that weekend

krit: we could just have a spec hacking session

heycam: so right after Houdini seems like the dates best for most people, except Rossen

Rossen: so that would be Aug 31 - Sep 2

RESOLUTION: We cancel the TPAC 2015 SVG meeting.
... We will tentatively try to meet in Paris after CSS/Houdini in Aug/Sep.

-- lunch --

RRSAgent: remind me in 4 hours to do something

<BogdanBrinza> To test IE11 on Mac/Linux go to http://dev.modern.ie/ and then Tools > RemoteIE

<krit> BogdanBrinza: it is just so much easier to ask you to check it :P

<krit> heycam: Does FF nightly use the UA style sheet rule for transform-origin currently?

<krit> found it

<krit> : svg.css:57;

<krit> : :not(svg)0px 0px 0px;

<shepazu> ACTION: Amelia to look at SVG spec for references to <use> element, to make sure there is no confusion about implementation/accessibility. [recorded in http://www.w3.org/2015/06/12-svg-minutes.html#action07]

<trackbot> Created ACTION-3812 - Look at svg spec for references to <use> element, to make sure there is no confusion about implementation/accessibility. [on Amelia Bellamy-Royds - due 2015-06-19].

<ed> https://github.com/w3c/svgwg/issues/18

<ed> https://github.com/w3c/svgwg/issues/20

<ed> ^ would like these two resolved

<ed> https://github.com/w3c/svgwg/graphs/commit-activity

<Rossen> https://www.w3.org/Graphics/SVG/WG/wiki/SVG2_Chapter_Assessment#Embedded_Content_.28Bogdan.29_.5Breadiness_4.5D

<Rossen> https://github.com/w3c/svgwg/graphs/commit-activity

<nikos> Trackbot, ACTION-3724?

<trackbot> ACTION-3724 -- Dirk Schulze to Do testing around currentscale, ctm, transform, viewport, etc. on 'svg' element -- due 2015-02-19 -- OPEN

<trackbot> http://www.w3.org/Graphics/SVG/WG/track/actions/3724

RRSAgent: make logs public

RRSAgent: make minutes

<scribe> Chair: Erik