Discussion:
[css-text-decor] Emphasis marks and combining characters
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i***@w3.org
2015-11-23 09:45:49 UTC
Permalink
https://drafts.csswg.org/css-text-decor-3/#text-emphasis-style-property

says

"The marks are drawn once for each character. However, emphasis marks
are not drawn for characters that are:
Word separators or that belong to the Unicode separator classes
(Z*). (But note that emphasis marks are drawn for a space that combines
with any combining characters.)
Characters belonging to the Unicode classes for control codes and
unassigned characters (Cc, Cf, Cn)."


presumably these marks should not be displayed for combining characters
either?


thinking a bit further, i wonder what happens for syllables in complex
indic and SE Asian scripts. Grapheme clusters may account for some
associations, but not those where multiple grapheme clusters comprise a
single syllable. Perhaps these emphasis marks are not really intended
to be used with complex scripts - if that's the case, perhaps we should
add a note to that effect.


Note, btw, that there is a possible requirement for this kind of
emphasis in Tibetan (see
http://w3c.github.io/tlreq/#emphasis_and_highlighting), but the mark is
centered across the syllable rather than tied to a single character. Do
we have any thought of catering for that in future versions of the spec?

ri
Xidorn Quan
2015-12-15 00:26:54 UTC
Permalink
Post by i***@w3.org
https://drafts.csswg.org/css-text-decor-3/#text-emphasis-style-property
says
"The marks are drawn once for each character. However, emphasis marks are
Word separators or that belong to the Unicode separator classes (Z*).
(But note that emphasis marks are drawn for a space that combines with any
combining characters.)
Characters belonging to the Unicode classes for control codes and
unassigned characters (Cc, Cf, Cn)."
presumably these marks should not be displayed for combining characters
either?
Actually there was a related discussion raised recently in HTML5
Chinese IG as well. That discussion is about whether emphasis marks
should also be skipped for punctuations. JLReq explicitly says
emphasis marks are not used for several punctuations (see 3.3.9 note
2), but the spec doesn't have anything around this.

- Xidorn
fantasai
2016-12-27 15:09:17 UTC
Permalink
Post by Xidorn Quan
Actually there was a related discussion raised recently in HTML5
Chinese IG as well. That discussion is about whether emphasis marks
should also be skipped for punctuations. JLReq explicitly says
emphasis marks are not used for several punctuations (see 3.3.9 note
2), but the spec doesn't have anything around this.
It was considered [1], but IIRC JLTF wanted us to include all punctuation
and make the author do the skipping because "what if the author wants
to emphasize that punctuation mark for some reason". Imho this is an
uncomfortable default for the Web because it means most publications
need to do a lot of markup mangling to get this to work right... but we
ended up deferring to that opinion. Maybe Koji remembers more, I can't
seem to find records of the discussion.
See http://drafts.csswg.org/css-text-decor-4/#text-emphasis-skip for
what was our last set of thoughts on the issue.
I'm happy to re-open the discussion if there's more input to consider.
Found more info on the background for this:
view-source:https://drafts.csswg.org/css-text-decor-4/Overview.bs

~fantasai
fantasai
2018-03-08 09:04:54 UTC
Permalink
The CSSWG and i18n Working Groups discussed an issue raised by Xidorn Quan
about placing emphasis dots over punctuation characters:
https://github.com/w3c/csswg-drafts/issues/839

According to JLREQ
https://www.w3.org/TR/jlreq/#composition_of_emphasis_dots
punctuation such as full stops, commas, and brackets should not receive marks.

The CSSWG and i18nWG discussed the issue and past recommendations from JLTF,
along with best practices for Web standards, and concluded to require that
such punctuation be skipped (along with spaces, which are currently skipped).
This gives the correct behavior by default and prevents authors from needing
to twist their markup to exclude punctuation in order to get the correct
rendering.

The changes have been added to the Editor's Draft of CSS Text Decoration L3:
https://github.com/w3c/csswg-drafts/commit/0b64606440b70efa47bc98db07c2537c8168c0ac
and an be seen at the bottom of the Emphasis Marks section at
https://drafts.csswg.org/css-text-decor-3/#text-emphasis-style-property


The CSSWG is requesting review from i18n, especially JLTF and CLTF on the list
of characters affected. Skipped punctuation is specified as
(Pc, Pd, Ps, Pe, Pi, Pf) or (Po and Sentence_Break=ATerm,Close,Scontinue,STerm)
the full list can be seen here:

https://unicode.org/cldr/utility/list-unicodeset.jsp?a=%5B%3AGeneral_category%3DPo%3A%5D%26%5B%5B%3ASentence_Break%3DATerm%3A%5D%5B%3ASentence_Break%3DSTerm%3A%5D%5B%3ASentence_Break%3DSContinue%3A%5D%5B%3ASentence_Break%3DClose%3A%5D%5D&g=Sentence_Break&i=

Please send any comments in reply to this message or add them to the issue
in GitHub at https://github.com/w3c/csswg-drafts/issues/839

Thank you~
~fantasai

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