Re: [css-text-decor] Doesn't example 3 in text-underline-position break current UA behavior?

On Fri, Jul 3, 2015 at 2:12 AM, Myles C. Maxfield <mmaxfield@apple.com>
wrote:

> Clarification appreciated since your arguments could read in two ways; I
> understand you want "auto" to do proper positioning between Latin and
> under. Are you also suggesting, when just "auto" is specified, it should
> set "right" (almost 100% for JK) and "left" (almost 100% for C if emphasis
> purposes IIUC)?
>
>
> I'm proposing that "auto" should take any and all context into
> consideration, including things like which language the text seems to have
> come from, how many characters in a row seem to come from that language,
> where line breaks occur, etc. Given all this information, "auto" can decide
> whether to put the line on the left or the right, and it can make this
> decision on whatever granularity makes the most sense (character, phrase,
> line, element, etc.). I'm also proposing that this behavior be able to be
> overridden using "under", "left", or "right".
>
> "auto" would mean "Do whatever you think is best"
> "auto left" would mean "For vertical writing modes, put the underline on
> the left. Otherwise, it's up to you."
> "under left" would mean "For horizontal writing modes, use the 'under'
> underline. Otherwise, (for vertical writing modes), put the underline on
> the left"
> "under" would mean "For horizontal writing modes, use the 'under'
> underline. Otherwise, do whatever you think is best"
> "left" is the same as "auto left"
>
> What are your thoughts?
>

Thank you for the clarification. I agree with you, but the spec was written
under the different assumption, that is why I asked clarification. In the
WG conf call (minutes here[1]), we discussed your proposal based on my
understanding, and I'm glad that I read your proposal correctly.

Historically speaking, at one point the WG did not like "auto" doing
language dependent "do whatever you think is best" and this spec was
written by following the rule. However, the horizontal positioning already
breaks the rule due to compat reasons, and when we discussed text-justify,
the WG changed to prefer "do whatever you think is best".

So I support your proposal, allowing "auto" to make the position automatic
for both horizontal and vertical.

And probably we want to apply the same logic to the text-emphasis-position
property[2] too.

Note that in the minutes, fantasai said if we were allowing auto to change
the position in vertical flow, she wants to change the syntax a bit more.

fantasai, what do you think? If you're fine, can you explain how you want
to adjust the syntax further?

[1] https://lists.w3.org/Archives/Public/www-style/2015Jul/0032.html
[2]
http://dev.w3.org/csswg/css-text-decor-3/#text-emphasis-position-property

/koji