[ttml2] Prune elements whose condition evaluates to false

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

== Prune elements whose condition evaluates to false ==
Where are presentation elements pruned if their condition evaluates to false? I propose adding a pruning condition to [construct intermediate document]:

_they are a _presentation related element_ associated with a _condition_ that evaluates to false_

This needs to avoid pruning, say, `style` elements whose condition evaluates to false, because that would break referential styling (a style whose condition is false may reference a style whose condition is true).

To be sure that is the case, we need to modify the term definition of [presentation related element] to explicitly exclude styling elements. This appears to be a harmless change right now.

Please view or discuss this issue at https://github.com/w3c/ttml2/issues/583 using your GitHub account

Received on Friday, 19 January 2018 10:54:32 UTC