Re: [css-text-decor] Emphasis marks and combining characters

On 11/23/2015 01:15 PM, ishida@w3.org wrote:
> 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?

The spec actually links "character" here to the CSS3 Text notion of "grapheme cluster".
It needs to be updated to use the new term "typographic character unit".
(New being relative here; Text Decoration was last published in 2013...)

So, this issue is *technically* invalid since we already link across,
but will really be fixed once CSS3 Text is republished *and* the spec
is updated to match terminology. :)

~fantasai

Received on Thursday, 22 December 2016 20:53:36 UTC