Applicability of tts:rubyPosition and tts:rubyAlign.

[spoeschel]

The tts:rubyPosition attribute applies to "span only if the computed value of tts:ruby is container". IMO this does not really make sense, as the ruby container is just a general container for text with ruby annotations (it may work though in the simple ruby case).

The tt:span that is actually affected corresponds to the ruby text content or instead (if present) the ruby text container. So the attribute should instead apply to a tt:span only if the value of tts:ruby is text (only in case tt:span is not a child of a ruby text container - as all ruby text content of the same ruby text container shall have the same position) or textContainer.

The current wording also does not work if double-sided ruby is used, as when relevant on the ruby container only, it would not be possible to specify the (different) positions in case two text containers are present. The double-sided ruby example next to the definition of tts:ruby is a good example for this issue. It uses tts:rubyPosition on ruby text container level - where it cannot be applied according to the current wording.

[skynavga]

In reviewing this issue and comparing the current spec text with CSS Ruby Layout Module Level 1, I have concluded that ruby position semantically applies only to an explicit or implicit Ruby Text Container, however, syntactically speaking, we may have Ruby Text Content that is not enclosed in a syntactically explicit span with tts:ruby="textContainer", so we need to accommodate both scenarios as mentioned in this issue (above).

I have also reviewed ruby align semantics, and there are two options here: (1) to take the approach of the above cited CSS Ruby Module and state that alignment semantics applies (collectively) to Ruby Base Container, Ruby Base, Ruby Text Container, and Ruby Text; or, alternatively, (2) state that alignment semantics apply to Ruby Container as a whole, which includes alignment of its constituent areas. At present, we already do this (in the applies row of the syntax table), but we don't elaborate the meaning of this. Therefore, I will add a note that elaborates this point. [I would also note that by applying alignment to Ruby Container, that a Ruby Container has only one possible alignment, i.e., one would have to divide content among multiple Ruby Containers to obtain distinct alignments.]

[palemieux]

then an author can specify it on any descendant

ancestor, right?

[skynavga]

@palemieux I edited my comment, so that text is no longer present. See the just posted PR (#740).

[palemieux]

syntactically speaking, we may have Ruby Text Content that is not enclosed in a syntactically explicit span with tts:ruby="textContainer"

What is the use case for this? It significantly complicates processing.

I have also reviewed ruby align semantics, and there are two options here:

The two options yield identical results, right? In other words, applying tts:rubyAlign="center" to the container is identical to applying tts:rubyAlign="center" to each of its text, base, baseContainer and textContainer elements.