Re: agenda+ css-writing-modes-3 review

Thanks for the outline of the specific outstanding issues, Koji,

I will be on the call next week, and between now and then I will look into
the issues and test cases you and fantasai have brought up.

Quite frankly, existing implementations of the SVG vertical writing spec
are so inconsistent and/or incomplete, and the spec itself is so vague in
places, that I have no problem setting an interpretation based on
consistency with the new spec.  (Maybe implementers will disagree!)  But
either way, it's good to then have a clear list of which previously
undefined behaviors we are now defining, and where existing implementations
need to change.

Amelia


On 2 October 2015 at 04:20, Koji Ishii <[email protected]> wrote:

> Dirk and Doug,
>
> In addition to what Doug said, a bit more clarification is appreciated.
> The clarification is blocking the spec to go CR, and two implementers
> appreciate the clarification for their work doing right now; Jonathan is
> working on it right now for Gecko, and I plan to do it next week for Blink.
>
> fantasai might explain this better in the conf call, but here's a summary.
>
> 1. The spec defines "treat as" map[1] between CSS and SVG values. Does
> that mean values in this table are completely equivalent, or does some of
> them have different semantics and the map indicates super/subset
> relationships? If equivalent, it means that "lr" and "rl" for instance
> behaves exactly the same.
>
> 2. If equivalent, can we pick one of the equivalent values as the
> canonical value? This will affect CSS serialization, which is used by
> getComputedValue and a few other places; whenever you parse CSS but then
> later want to stringfy, serialization kicks in.
>
> 3. If not equivalent, which value is not equivalent, and how is it
> different?
>
> I can read from SVG specs that writing-mode lr/rl sets "the initial
> inline-progression-direction" and direction ltr/rtl sets "the base writing
> direction", but I couldn't find what "the initial
> inline-progression-direction" is from the spec.
>
> If these two terminologies actually are the same thing, and "writing-mode
> lr/rl sets the initial inline-progression-direction" is not a valid
> definition, these values can be equivalent. Blink does so, and from the
> tests, other browsers seem to be doing so too.
>
> Given that, Jonathan and I prefer these values are equivalent, and pick
> the current CSS values as canonical. We appreciate SVG WG thoughts and
> resolution on this.
>
> [1] https://drafts.csswg.org/css-writing-modes-3/#svg-writing-mode-css
>
> /koji
>
>
> On Fri, Oct 2, 2015 at 1:21 PM, Doug Schepers <[email protected]> wrote:
>
>> Hi, Dirk–
>>
>> Fantasai wrote up the results from the discussion and wants the SVG WG to
>> confirm that it matches what was agreed.
>>
>> Regards–
>> –Doug
>>
>>
>> On 10/2/15 12:14 AM, Dirk Schulze wrote:
>>
>>>
>>> On Oct 1, 2015, at 4:08 PM, Doug Schepers <[email protected]> wrote:
>>>>
>>>> Hi, Dirk, Amelia, Cameron–
>>>>
>>>> We decided that we need (at least some of) you on the telcon to
>>>> really deal with this issue and help move the CSS Writing Modes 3
>>>> spec to CR.
>>>>
>>>> Are you available to be on the telcon next week?
>>>>
>>>
>>> I wonder what the issue is. I thought we resolved the last open
>>> issues at the FX TF meeting in Paris a couple of weeks ago?  fantasai
>>> and Cameron were both it the meeting and overruled me :D. I myself
>>> will not be able to join.
>>>
>>> Greetings, Dirk
>>>
>>>
>>>> Tav is going to be reviewing the spec in depth, and you can
>>>> coordinate with him to provide feedback, if you can't be on the
>>>> telcon.
>>>>
>>>> Thanks– –Doug
>>>>
>>>> On 9/30/15 9:58 PM, Doug Schepers wrote:
>>>>
>>>>> Hi, Erik–
>>>>>
>>>>> Can we please add the CSS Writing Modes 3 spec review to the
>>>>> agenda? Fantasai says she needs our feedback on 2 issues (listed
>>>>> below), and she's available to attend the telcon tomorrow to
>>>>> explain the issue.
>>>>>
>>>>> (Fantasai, telcon details below in Erik's original agenda
>>>>> email.)
>>>>>
>>>>> [[ I'm blocked on the SVGWG here:
>>>>> https://drafts.csswg.org/css-writing-modes-3/issues-cr-2014
>>>>>
>>>>> Two issues require SVGWG review
>>>>>
>>>>> first one is
>>>>> https://lists.w3.org/Archives/Public/www-svg/2015Sep/0016.html
>>>>>
>>>>> That's the one that needs review of spec wording
>>>>>
>>>>> second issue is this
>>>>> https://lists.w3.org/Archives/Public/www-svg/2015Sep/0017.html
>>>>>
>>>>> The question on hand is whether we can fold 'writing-mode: rl'
>>>>> and 'writing-mode: lr' together
>>>>>
>>>>> From a CSS perspective, they're the same
>>>>>
>>>>> The different values don't affect anything in the CSS model
>>>>>
>>>>> They're both horizontal writing modes, and the rl vs. lr doesn't
>>>>> affect bidi
>>>>>
>>>>> But the SVG spec says they affect the "inline progression
>>>>> direction" and I can't figure out what that means or should have
>>>>> an effect on
>>>>>
>>>>> But it's quite clear that it doesn't affect reordering!
>>>>>
>>>>> There's a test file here
>>>>> https://lists.w3.org/Archives/Public/www-svg/2015Sep/att-0027/test.svg
>>>>>
>>>>>
>>>>>
>>>>> which does very interesting things in Presto
>>
>>>
>>>>> but otherwise renders the two values identically in Blink and
>>>>> InkScape
>>>>>
>>>>> So, yeah, have fun with that?
>>>>>
>>>>> maybe someone in the group knows what the SVG spec was trying to
>>>>> say, and whether or not it was important ]]
>>>>>
>>>>> Regards– –Doug
>>>>>
>>>>> On 9/30/15 4:46 PM, Erik Dahlström wrote:
>>>>>
>>>>>> Please find the agenda for this week’s telcon below.
>>>>>>
>>>>>> Time:
>>>>>>
>>>>>> http://www.timeanddate.com/worldclock/fixedtime.html?month=10&day=1&year=2015&hour=20&min=30&sec=0&p1=0
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> Phone: +1-617-324-0000 (access code: 649 040 824)
>>
>>> IRC for minutes/discussion: #svg on irc.w3.org, port 6665
>>>>>> Agenda requests: http://www.w3.org/Graphics/SVG/WG/wiki/Agenda
>>>>>> WebEx logistics: https://www.w3.org/Graphics/SVG/WG/wiki/WebEx
>>>>>>
>>>>>> Agenda:
>>>>>>
>>>>>> * Path stroking for paths that end with tight curves (Tav)
>>>>>> http://tavmjong.free.fr/blog/?p=1257
>>>>>>
>>>>>> * Declarative animation and conformance
>>>>>> https://github.com/w3c/svgwg/issues/23
>>>>>>
>>>>>> * SVG 2 chapter progress
>>>>>>
>>>>>>
>>>>>
>>>
>>
>