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[CSSWG] Minutes Telecon 2016-03-16 [css-snappoints] [css-2015] [css-ui] [css-values]

From: Dael Jackson <daelcss@gmail.com>
Date: Wed, 16 Mar 2016 19:45:58 -0400
Message-ID: <CADhPm3v=PQGwF-OAZpPHYYw_zP9WEPD+6WHN=aa7LP191=sF3A@mail.gmail.com>
To: www-style@w3.org
=========================================
  These are the official CSSWG minutes.
  Unless you're correcting the minutes,
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Future F2Fs
-----------

  - There will be room for everyone on every day at the May F2F
      thanks to the efforts of Ojan and Shane.
  - The Houdini group needs to decide if and when they'll need room
      at TPAC.

CSS Snap Points
---------------

  - RESOLVED: Publish new WD of CSS Snap Points

Snap Size FPWD (short name TBD)
-------------------------------

  - Step-sizing received favor as a new name.
  - Several implementors hadn't had time to review the spec. Though
      they were interested in solving the problem space, they
      weren't prepared to affirm that this ED is the direction they
      believe the group should go to solve it.
      - Implementors were given another week to review the spec in
          hopes of being able to resolve.

We have an issue in the 2015 Snapshot for adding Will Change once it
    hits CR
---------------------------------------------------------------------

  - RESOLVED: Republish 2015 snap shot with Will Change added.

CSS UI Implementor feedback on allowing pseudo-elements on form
    controls when appearance:none
---------------------------------------------------------------------

  - TabAtkins will write up a proposal for checkbox and radio
      buttons for next week detailing his thoughts while everyone
      else reviews the e-mails.

CSS Values
----------

  - RESOLVED: Allow calc() to be nested.
  - RESOLVED: Drop calc() from nested calc() and serialize it as
              parentheses.
  - calc() simplification for serializing specified values will
      continue on the mailing list and be on next week's agenda if
      needed.

===== FULL MINUTES BELOW ======

Agenda: https://lists.w3.org/Archives/Public/www-style/2016Mar/0233.html

Present:
  Rossen Atanassov
  Tab Atkins
  Bert Bos
  David Baron
  Dave Cramer
  Elika Etemad
  Simon Fraser
  Daniel Glazman (IRC only)
  Tony Graham
  Koji Ishii
  Dael Jackson
  Brad Kemper
  Peter Linss
  Anton Prowse
  Matt Rakow (IRC only)
  François Remy
  Florian Rivoal
  Alan Stearns

Regrets:
  Tantek Çelik
  Greg Whitworth

Scribe: dael

Future F2Fs
===========

  Rossen: Let's get started
  Rossen: Are there any additional agenda items?
  Bert: Maybe a reminder that Houdini needs to decide if they are
        meeting at TPAC.
  Rossen: Thank you Bert. We did discuss and we want to meet. I'll
          send a mail to the Houdini list and if everyone is on
          board we'll reserve with you. Thank you for the reminder.

Snap Points
===========

  fantasai: Can we publish CSS snap points since there isn't hope of
            it getting more up to date?
  Rossen: Are all editors on the call?
  fantasai: I have no idea. Why don't you ask MaRakow if he wants to
            publish or not.
  Rossen: MaRakow are you on the call?
  <MaRakow> Irc only
  <fantasai> Question is just, should we publish what we have
  <fantasai> or rather, what MaRakow has so far
  <fantasai> so at least there's an update from the previous
             publication
  Rossen: IRC Only. Okay. We'll ask him or IRC and review this at
          the end with IRC responses.
  Rossen: Anything else that needs to be added?
  <MaRakow> It's fine to publish what's there currently, I requested
            this previously.

Future F2Fs
===========

  Rossen: Quick reminder on May F2F. We'll be hosted at Google.
          There will be enough room for everyone on all days,
          including Wednesday. Thank you again for pulling this
          together on short notice, especially Shane and Ojan.
  Rossen: If you haven't booked, I'd recommend doing so. I'm not
          sure if there's anything big, but when I was tying to book
          there weren't too many options.
  Florian: If anyone is interested in AirBnB it's time we coordinate.
           I'm interested.
  Rossen: Florian, if you could just start a thread on the private
          list it would be great.

Snap Points
===========

  fantasai: MaRakow says he thinks it's fine to publish. Can we
            resolve and someone action to publish?
  Rossen: Yes, let's vote. Objections to publishing CSS snap points
          as a new WD?

  Florian: One question, where are we?
  Florian: Along the merging process moving TabAtkins and fantasai
           items into MaRakow draft?
  * fantasai is guessing we are about 50% there
  Rossen: MaRakow is on IRC and is the one in the position to answer
          that.
  Rossen: As far as I know there's still outstanding merges, but the
          spec is in consumable version so there's no reason not to
          publish from that PoV.

  Rossen: Any objections or questions?
  Rossen: I'll take that silence as a no. Is there even interest?
  Florian: I'm more interested in where this is, but I'm excited to
           work on it.
  Rossen: I'm glad there's interest.
  <MaRakow> awesome :)
  fantasai: There HAS been interest!
  <fantasai> If there wasn't any interest in it, Tab and I wouldn't
             have dropped everything to work on it between the Paris
             and TPAC F2Fs, and there wouldn't be 3 implementations
             of varying bits of its functionality!!!!
  <Rossen> fantasai: let me reiterate again that what you and Tab
           did was great work. The editor of the draft also did a
           lot of work for the few years before that but the other
           implementers weren't implementing yet.

  RESOLVED: Publish new WD of CSS Snap Points

  <TabAtkins> I do question why there are any outstanding merges at
              this point, months after we were promised a complete
              draft and assured there's no need to add fantasai or I
              as editors to get it done.

Snap Size FPWD (short name TBD)
===============================

  <astearns> https://drafts.csswg.org/css-snap-size/
  <astearns> name suggestion: step-sizing
  <SteveZ> name suggestion: line-height-adjust
  koji: There was a discussion on property names. I think the best
        suggestion is step instead of snap.
  koji: The spec has the updated language.
  koji: The only thing I haven't changed is the short names because
        I wanted to get confirmation from the WG if these new names
        are okay and if we can publish.

  Florian: Last time we discussed there was a request from me for
           extra time and I need to apologize because I've been busy
           and have not. I do want to review and I haven't. I'm not
           sure if the others that wanted to review have had time.
           On my part I haven't. I'm really sorry.
  * fantasai hasn't had a chance to review, either
  astearns: I've reviewed and like the current state. I suggest we
            name it step-sizing.
  astearns: At the moment the title is CSS step size. We have CSS
            sizing in another draft so I was thinking step-sizing
            would work.
  koji: Can we go for that as both title and short name?
  astearns: Right.
  astearns: SteveZ mentioned line-height-adjust in IRC. This isn't
            just height and I'd hope this wasn't just line boxes, so
            I'd rather not restrict.
  koji: I'm good with that.

  Florian: Though I haven't had time to review, I know I shared
           concerns with astearns so that gives me some comfort. I'd
           still like to review.
  fantasai: I haven't had a chance to review either. My opinions
            aside, I'd like the WG to have consensus that this is a
            thing we want rather than some people saying it's an
            okay idea and others being eh. I think FPWD should be
            created when the WG has a positive, not a neutral opinion.
  fantasai: If there's only interest from koji and astearns and no
            other implementors that's not a good sign. If people
            think this is cool, then we should proceed. I want to
            hear from more people rather than have silence as a
            reason to publish.
  Florian: As an implementor I'm interested in the problem space,
           but I haven't reviewed the spec enough to meet that bar.
  Rossen: That's a fair point. Other implementors? Apple? Mozilla?
  Rossen: Can you talk in terms of interest?
  smfr: It's worth considering, but not high priority. It seems like
        a generally useful thing to implement long term.
  Florian: Are you interested in solving the problem, or solving it
           in this specific way?
  smfr: In the problem space. I'm not familiar enough with other
        solutions to be able to judge against those.
  dbaron: I'd like a chance to look at the spec. It's hard to
          comment now. Based on some discussions there was some
          interest, but hard to say amount.
  Rossen: For Edge I'll say along the same lines. It's an
          interesting problem to solve. The way Koji proposes to
          solve is interesting. In terms of priority it won't be
          high on the list for us for impl or spec work.
  <dbaron> What's the URL for this draft?
  <dbaron> (I don't see a URL in the agenda)
  <koji> dbaron: https://drafts.csswg.org/css-snap-size/

  Rossen: If I have to summarize as a chair, sounds like the
          interest is low to moderate.
  Rossen: Is it worth waiting a week or two for the rest of the
          people to review the spec?
  <astearns> the spec is relatively short - it should not take too
             much time to review
  fantasai: I would really appreciate having Florian and dbaron take
            a more detailed look. I'd like to do that myself. I
            don't feel we have a very strong sense of this is
            definitely the right way to solve this. We have this is
            an interesting possible solution. I'd like to get to
            where we had something that is how we believe we want to
            solve the problem and then go to publish.
  fantasai: We have the ED so we can see. Rather than have 5 modules
            of 5 proposals, I'd rather we explore as to if this is
            the right direction and do WD when we're confident it's
            going in the right direction

  <dbaron> How does this relate to line-grid proposals?
  astearns: In regards to it relating to line-grid proposals, this
            is a useful tool for when you are using a line-grid.
  astearns: The line-grid will cause things to move and snap into
            place depending on the line height and grid spacing
            relationship. This is a way to ensure that the ratio is
            such that they do not shift. So this is complementary,
            particularly when related to block.
  Florian: This is part of why I want to review. It would be good
           for them to be complementary. I want to see how they work
           in the inline direction too.
  Rossen: So we'll give it another week or two if someone asks for
          two on the ML. When enough people have reviewed we'll
          discuss.

CSSOM 4 Selectors Review
========================

  <Rossen> https://lists.w3.org/Archives/Public/www-style/2016Mar/0213.html
  astearns: This is mainly a reminder that we agreed to look at the
            CSSOM one section a month and thi sis this months'
            section.
  astearns: If people have comments to make now, great. If not take
            this as notice you should look at this short section and
            help us finish it up.
  <glazou> thinks that section is ok
  <glazou> has one extra comment though
  Rossen: We have glazou at least that thinks it's ok. Anyone else
          show is currently ready to comment? Or is this an action
          to start review?
  fantasai: We should all take it as an action.

  ACTION everyone review this section of CSSOM 4 by the end of the
         month

CSS UI Implementor feedback on allowing pseudo-elements on form
    controls when appearance:none
=====================================================================

  <Rossen> https://lists.w3.org/Archives/Public/www-style/2016Mar/0190.html
  Florian: This is TabAtkins with me replying.
  <TabAtkins> Be in in just a sec.
  Florian: Is TabAtkins there? If not let's delay a bit more
  Florian: Do we have a short topic?

We have an issue in the 2015 Snapshot for adding Will Change once
    it hits CR
=====================================================================

  <Rossen> https://www.w3.org/TR/css-2015/#issue-d34d1161
  Rossen: We have an issue for adding Will Change once it hits CR. I
          believe this is fantasai.
  fantasai: So should I create a new draft with that added and
            republish as the 2015 snapshot as intended?
  Florian: I think so, or is it 2016?
  fantasai: I think 2016 we can do later.
  Florian: Okay, I don't care strongly.
  <Bert> Let's publish a new snapshot, don't care if it is called
         2015 or 2016.
  Rossen: So objections to republishing 2015 snap show with Will
          Change added?

  RESOLVED: Republish 2015 snap shot with Will Change added.

  * TabAtkins is here now
  Rossen: fantasai please do the republishing and thank you.

CSS UI Implementor feedback on allowing pseudo-elements on form
    controls when appearance:none
=====================================================================

  TabAtkins: The issue is about standardizing the use of
             ::before/after on form controls. This is possible on
             webkit and blink today.
  TabAtkins: In general if you do ::before/after you'll get
             something useful. Typically you do appearance:none to
             wipe out the checkbox and use this to create cool
             styles. However these are not interoperable.
  TabAtkins: I know in general inputs are semi-replaced. I don't
             want to change that in general because figuring out
             what's in an input across platform is hard. We think we
             could handle just when there's appearance:none which
             makes it an empty <div>. We can say ::before/after work
             there. If we can spec this we can get interoperability.

  dbaron: In Chromium, does saying appearance:none on a check box
          makes it an inline block? Because I don't think that's
          Gecko, but we could do that.
  Florian: I think to the extend we can make appearance:none
           non-replaced I'm in favor. I'm not entirely sure we can
           make all types of things non-replaced. Do we go through
           every form element and decide if it can become a <div>?
  TabAtkins: This list isn't very long. I'm happy to go through what
             we can do. Checkboxes and radio are on the list. If we
             can figure out how to make appearance:none work in a
             way that matches what we do we should do that
  Rossen: Does making appearance:none take the check box out of the
          form control? Like that's not a check box?
  TabAtkins: It is still a checkbox for a11y purposes and whatnot.
             It removes the appearance.
  Rossen: So it's a checkbox but doesn't look like one.
  TabAtkins: Yeah.
  Florian: It's appearance not behavior.
  Florian: The way I specced it everything that only pertains to
           appearance has to be removed, but behavior must stay.
           That's fairly easy for checkbox because behavior is only
           DOM. Something like a dropdown calender still needs to
           look special when you interact. It can't be entirely
           flattened.
  Florian: Out of these, do some need to be replaced? If can say
           everything is flatted with appearance:none that's great,
           but if there's an exception we need to know.
  TabAtkins: I'm saying radio and checkbox now because they're
             simple. Look through the rest later.
  Rossen: On our end I'd need to take a bit more time to see what it
          means.
  ACTION Rossen review appearance:none and ::before/after email

  Florian: What you suggested sounds great. You wanting to start a
           new doc, I'm not sure why you'd need separate section.
  TabAtkins: Not a separate spec, just a doc to be able to drop in.

  TabAtkins: dbaron did you have implementation concerns?
  dbaron: If this is compatible with what Chromium does I'm okay.
          There may be some questions on appearance vs. webkit-
          appearance.
  TabAtkins: So how about I do a proposal for next week. In the mean
             time, Rossen explores the basic idea. Then we discuss
             next week.

  <bradk> How about ::before and ::after on images?
  * Bert is with bradk: wants them on images, too. (But realizes
         this will be a difficult to define...)
  smfr: bradk mentioned something on images. You can use the style
        not on broken images. We need a general review on
        ::before/after on replaced.
  TabAtkins: A broken image isn't quite defined if it's replaced or
             not.
  fantasai: It is defined in HTML spec and it's not replaced.
  TabAtkins: Form elements are never strictly defined to be replaced.
             We don't define what's inside of them in any meaningful
             way.
  <astearns> form elements are explicitly defined as non-replaced,
             in that they're in the non-replaced elements section in
             the html spec

  Florian: dbaron while you think on this you may want to ring Boris
           because I know he's mentioned this on WHATWG.
  TabAtkins: He suggested what I'm suggesting.
  Florian: In the discussion about appearance:none
  TabAtkins: We looked to see if we could remove our code, the usage
             is too high so we can't. He suggested appearance:none
             as the key to keep.
  <Florian> https://github.com/whatwg/compat/issues/6#issuecomment-188081087
  Florian: He suggested that with appearance:none some things will
           need to stay.
  Florian: Take that as a part of your homework.
  Rossen: So TabAtkins will write his explainer document for
          checkbox and radio and we'll see if we can generalize more
          to other elements.

CSS Values
==========

Nesting calc() and serialization
--------------------------------

  <Rossen> https://lists.w3.org/Archives/Public/www-style/2016Mar/0042.html
  TabAtkins: This set of topics are in CR so we need approval of
             changes.
  fantasai: The last one doesn't have clear conclusion.

  TabAtkins: This is calc() and nesting. It was always intended that
             calc() be nestable. Any items inside a calc(). We
             intended the addr function for example. This is
             required to make variables work more easily.
  TabAtkins: The way I defined calc() technically only allows
             literals inside itself. I fixed this up and made sure
             calc() was written in generic concepts not literal.
  fantasai: I want to double check the edits for unintended effects.
            We need the group to agree calc() can be nested and that
            the inner calc() serializes out as parentheses. Does
            that sound good, bad, need more time?
  TabAtkins: Nesting calc() is the same as putting parentheses
             around things.
  fremy: In 2012 I wrote tests in the values test suite on this.
         It's in the test suite so I'm in favor of supporting the
         change.

  <fantasai> ACTION: fantasai review wording changes for nesting
             calc() to avoid unintended changes.
  <trackbot> Created ACTION-760

  TabAtkins: Objections to making calc() nestable in the spec?
  Rossen: Does anyone allow nested calc()?
  <bradk> No objection from me.
  TabAtkins: I don't remember if we do, but the way implementations
             handle calc() is ad hoc. It wouldn't surprise me.
  Rossen: I think we don't allow nesting. So this will be at least a
          functional change.
  Rossen: I'm curious what that means for other implementors.
  TabAtkins: It's a functional change in so far as if you accept the
             format. It's not new behaviors, just syntax.
  Rossen: I'm just curious if someone supports this.
  TabAtkins: Don't know. I'm not pegging this on a compat bug.
  TabAtkins: You care about compat when it matters for page support,
             not for every single detail of an implementation.
  Rossen: In the context of calc() as long as it become equivalent
          of parentheses we should be fine. We don't support it now,
          certainly.
  TabAtkins: Do you object to the spec change?
  Rossen: No.
  <Bert> (I'm fine with nested calc, no opinion on how it
         serializes, other than that it does, somehow. :-))

  <dbaron> I don't think we should look at introducing new features
           as a compatibility issue unless there's an actual
           compatibility problem we know about.

  TabAtkins: If no one else objects we can resolve.
  fantasai: There's 2 points.
  TabAtkins: They're independent. Does anyone object to allowing
             calc() to be nested?
  Rossen: Are there restrictions to level of nesting?
  TabAtkins: No. They're just like parentheses.
  Rossen: Okay, any objections, time requests?

  RESOLVED: Allow calc() to be nested.

  Rossen: I'm assuming you'll make the change?
  TabAtkins: Yeah.

Clamping calc() values, serialization thereof
---------------------------------------------

  <Rossen> https://lists.w3.org/Archives/Public/www-style/2016Feb/0160.html
  TabAtkins: So do we need nested calc(), or treat them as
             parentheses and serialize as such. I don't care either
             way, but we need to decide. If the WG wants to keep the
             exact form we can go with that.
  Rossen: Feedback? Comments?

  Rossen: glazou is up.
  Rossen: We have to read IRC as he types.
  <glazou> the question is: will web authors understand they have
           nested calc() when there's only ()
  <glazou> in a serialization
  <glazou> and what's impact on OM
  TabAtkins: [reads first question] I don't understand.
  <glazou> calc(... ())
  Rossen: He's asking if you serialize back only parentheses when
          calc() was nested, would there be loss where people
          wouldn't know if this was calc() or parentheses and would
          that matter.
  <glazou> what Rossen said
  TabAtkins: Doesn't matter anyway because they're equivalent.
  <glazou> no that matters in OM
  Rossen: They're logically equivalent but for editors they may not
          be.
  <glazou> you have to know to be able to tweak it programmatically
           if you need
  fremy: I don't see why someone would write calc() inside calc().
         The only reason we allow this is to allow variables in a
         calc(). I don't expect impact on authors.
  Rossen: This would also impact tools. Tools can add nested calcs
          and they may expect it to be serialized back.
  <glazou> right
  <TabAtkins> Yeah, important case is "--foo: calc(1px + 2em); --
              bar: calc(var(--foo) + 10vw);"
  <TabAtkins> If calcs cant' be nested, you have to do some clumsy
              stuff instead.
  Florian: The general tooling argument about preserving more syntax
           is better because you get more author intent. In general
           I agree. In this case there isn't different author intent.
           The only case where you want calc() to nest is when
           variables do it for you. It's not something you'd want to
           preserve.
  * glazou agrees that computations have to be nestable
  TabAtkins: I don't see when you would have a compound expression
             where you'd put a calc() in purpose. You may have a
             compound made of a bunch of calcs and you would
             serialize that out.

  <glazou> would prefer a model where what's inside calc( and ) can
           be more complex than a single operation and still be a
           single calc()
  <glazou> but of course we had that discussion several times in the
           past
  <TabAtkins> glazou: Yes, that's already allowed. Again, nesting
              calc() offers *no new functionality whatsoever*.

  <smfr> do we need () for precedence? calc(A * (B + C))
  <TabAtkins> smfr: Yeah, parens already exist, for that purpose
              exactly.

  Rossen: I would suggest keeping the PoV where an editor has a
          button that adds a calc() button and you can do it as many
          times as you want. It's a valid test case.
  Florian: I think what we're saying is if you're nesting it's
           preferable to use parentheses. Writing extra code to
           support sub-optimal usage isn't good. If we can come up
           with a use case where you're gaining anything, that's
           fine. It's worth dropping information to avoid a noisy
           stylesheet.
  fantasai: This is about as significant as to if you used tab or
            spaces for indentation. At some level you'll care, but
            for the APIs in the CSSOM it doesn't matter any more.
  Florian: Since our OM doesn't fully preserve, we're not at that
           level.

  <Florian> sorry Daniel, I'm usually on the same side as you on
            these questions, but this time it feels the other way is
            better.
  <glazou> Florian np
  <Florian> but I can still see where you're coming from.
  <glazou> I am trying to help understanding better the request,
           that still seems obscure to me for potential harm for
           editors

  Rossen: It sounds like there's not a lot of push back on the call.
          The person trying to object is glazou. glazou will you
          need more time or are you okay resolving to drop calc() on
          parentheses.
  <glazou> no I am not objecting
  Rossen: And while we wait, should we postpone the next topic?
  TabAtkins: Next one maybe.
  fantasai: When you're serializing the computed value of calc, yeah.
  Rossen: So glazou doesn't object to dropping calc() from nested
          calc() and leaving it as parentheses. Anyone object?

  RESOLVED: Drop calc() from nested calc() and serialize it as
            parentheses.

calc() simplification for serializing specified values
------------------------------------------------------

  <Rossen> https://lists.w3.org/Archives/Public/www-style/2016Feb/0160.html
  fantasai: So it's if we perform clamping because serialization.
  <TabAtkins> calc(10px - 1em) <== positive? negative? can't tell at
              parse time.
  fantasai: So in the past if you have -5 in calc() we'd drop at
            parse. We can't do that. So if we're serializing, do we
            perform clamping and than serialize it out.
  TabAtkins: It's not if we should, it's I spec it and it needs to
             be checked for correct. We can't tell if calc() is +
             or -. If it resolves outside the range we clamp. But
             there's also a rule that we unwrap the calc() if it's a
             single value at certain stages. We have to clamp or it
             doesn't round trip. I wrote the rules, we need approval
             on those changes.
  <dbaron> I'd like more than 30 seconds to review this issue...

  Florian: And the rest was discussed years ago?
  TabAtkins: Yes, the existence of clamping was decided years ago
  fantasai: We spec it does, but not what stage.
  TabAtkins: And because the unwrapping we have to say how and when
             it happens. We clamp as soon as possible at computed
             value time. If you unwrap you pop out the clamped value.

  <fantasai> https://drafts.csswg.org/css-values-3/#calc-serialize
  fantasai: Here's the section. The two things to pay attention to
            are clamping and how do we manage the simplification of
            calc() for serializing.
  fantasai: Those are the issues, they're in the DoC.
  <fantasai> clamping issue
https://drafts.csswg.org/css-values-3/issues-cr-2015#issue-11
  <fantasai> simplification issue
https://drafts.csswg.org/css-values-3/issues-cr-2015#issue-17

  Rossen: In interest of time, let's go to the ML. If we can't
          resolve there we will do this next week.
  Rossen: Remember next week we'll still be one hour earlier.
  Rossen: Thanks and we'll chat next week.
Received on Wednesday, 16 March 2016 23:46:57 UTC

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