[ttml2] Applicability of `tts:rubyPosition`

spoeschel has just created a new issue for https://github.com/w3c/ttml2:

== Applicability of `tts:rubyPosition` ==
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`](https://w3c.github.io/ttml2/#style-attribute-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.

Please view or discuss this issue at https://github.com/w3c/ttml2/issues/717 using your GitHub account

Received on Wednesday, 25 April 2018 11:18:25 UTC