[ttml2] condition="forced" does not match the behavior of itts:forcedDisplay

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

== condition="forced" does not match the behavior of itts:forcedDisplay ==
TTML2 states:

> For the purpose of presentation processing, if an element specifies a condition attribute, and the its <condition> expression value evaluates to false, then the semantics of the element and its descendant elements must be ignored unless explicitly specified otherwise.

In contrast, IMSC1 states:

> a content element with a itts:forcedDisplay computed value of "false" shall not produce any visible rendering, but still affect layout, regardless of the computed value of tts:visibility.

It is therefore not possible to achieve the `itts:forcedDisplay` using `condition="forced"`.

Please view or discuss this issue at https://github.com/w3c/ttml2/issues/482 using your GitHub account

Received on Monday, 6 November 2017 22:42:03 UTC