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w3c / ttml2

Timed Text Markup Language 2 (TTML2)
https://w3c.github.io/ttml2/
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Ruby constraints cannot be validated prior to ISD construction #1140

Closed palemieux closed 4 years ago

palemieux commented 5 years ago

Validation of ruby constraints can only happen after ISD construction since:

Is that the intent, or are should ruby style properties be specified solely using:

edit.: added impact of conditionalized styles

skynavga commented 5 years ago

At first order, I do not agree with this your statement that validation can only occur after ISD construction. If the initial value of tts:ruby is not changed by an initial element, then validation can occur before ISD construction. Notwithstanding this point, I do not know of a use case for changing the initial value of tts:ruby, so I would be happy to propose a PR that disallows such a change, i.e., by constraining the semantics of initial, or by specifying such constraint in the context of the definition of tts:ruby, which would be preferable (to preserve locality of reference).

palemieux commented 5 years ago

@skynavga What about the impact of using condition on a style element that specifies tts:ruby?

skynavga commented 5 years ago

Added to TPAC Agenda, https://www.w3.org/wiki/TimedText/tpac2019#Topics.

nigelmegitt commented 5 years ago

I see that #1146 has been opened before the TTWG has discussed this at length and worked out what we want to do with it. I will hold off any review of that pull request for the time being until we know what we need.

skynavga commented 5 years ago

@nigelmegitt are you suggesting there is something unusual about opening a PR before the WG has discussed an issue? it is my firm conviction that it is ALWAYS better to have a PR open by the editor before discussing an issue, and this has been typical for past practice as well; in fact, it is the duty of the editors to take the lead in proposing solutions to issues, which is what PRs are for; I sincerely hope you are not attempting to suggest there is an existing policy or propose a new policy that would require the WG to discuss an issue before an editor takes the initiative to draft a PR; further, I suggest we do not discuss this policy matter in this conversation, which is off topic;

nigelmegitt commented 5 years ago

@skynavga It's reasonable to have a concrete starting point for a discussion - I'm happy to treat this pull request as that.

css-meeting-bot commented 4 years ago

The Timed Text Working Group just discussed Ruby constraints cannot be validated prior to ISD construction #1140, and agreed to the following:

The full IRC log of that discussion <cyril> Topic: Ruby constraints cannot be validated prior to ISD construction #1140
<cyril> github: https://github.com/w3c/ttml2/issues/1140
<cyril> pal: the problem is that the constraints are expressed based on properties not elements
<cyril> ... so you cannot validate them until you are in an ISD
<cyril> ... we have spans that behave like elements
<cyril> ... there are 3 options: we can say validation is done after ISD; we can constrain the application of a style resolution such that you can validate before style resolution; or say it was a mistake and change it to elements
<cyril> glenn: I prefer option 1
<cyril> pal: condition has a problem that we don't have a model that says when it's executed
<cyril> nigel: there is no disagreement that has to be after ISD construction
<cyril> pal: this requires a huge change in IMSC.js
<cyril> nigel: there are 2 ways you can modify a property, but set/animate or by initials
<cyril> glenn: the PR makes them non animatable
<cyril> glenn: in TTT it validates after ISD construction
<cyril> pal: what I would like is them to be elements
<cyril> cyril: it's too late
<cyril> pal: the way it is specified today is terrible
<cyril> nigel: I don't see any advantage in making them not alterable by initial
<cyril> ... the conditional one has also some problems
<cyril> pal: yes, conditional has other problems
<cyril> nigel: the answer to the question in the issue, is yes that is the intent
<cyril> cyril: should we close the issue with no change?
<cyril> nigel: yes
<cyril> glenn: do we want to let the initial change the initial value from none to ruby?
<cyril> cyril: it's up to authors not to do crazy things
<cyril> glenn: I'm ok with that
<cyril> RESOLUTION: we close the issue with no action
<nigel> SUMMARY: Yes. we confirm that validation of ruby constraints can only happen after ISD construction.
skynavga commented 4 years ago

Per TPAC 2019 TTWG meeting, closing this PR without merging.