Feature #textOrientation-sideways-LR listed twice

[spoeschel]

In §6, the feature #textOrientation-sideways-LR is listed twice - with different dispositions for the Text profile.

[nigelmegitt]

Thanks for this @spoeschel , this is a substantive issue.

[css-meeting-bot]

The Working Group just discussed Feature #textOrientation-sideways-L listed twice imsc#373, and agreed to the following resolutions:

• SUMMARY: This needs a bit of digging to find out what we meant and wanted. To do!

The full IRC log of that discussion

<nigel> Topic: Feature #textOrientation-sideways-L listed twice imsc#373
<nigel> github: https://github.com//issues/373
<nigel> Nigel: This is substantive - it isn't clear what the disposition for #textOrientation-sideways-LR is
<nigel> .. as Stefan spotted.
<nigel> Cyril: Given that #textOrientation itself is completely prohibited, maybe #textOrientation-sideways-LR
<nigel> .. is also prohibited, but maybe we need to dig into the history on this.
<nigel> Pierre: I have not had time to review that. I don't want to guess!
<nigel> .. It will get done.
<nigel> SUMMARY: This needs a bit of digging to find out what we meant and wanted. To do!

[nigelmegitt]

I've checked the definition of #textOrientation and it indeed appears that prohibiting #textOrientation prohibits all use of it, so permitting any subset of value makes no sense. Therefore there are two options:

1. Prohibit #textOrientation-sideways-LR in Text and Image profiles, and make no other change.
2. Make #textOrientation for Text profile partly permitted, and permit or prohibit #textOrientation-sideways-LR for Text Profile depending on what we actually need.

Permitting #textOrientation but prohibiting #textOrientation-sideways-LR means that the value for tts:textOrientation must be one of: "mixed" | "sideways" | "upright" and must not be one of: "sidewaysLeft" | "sidewaysRight". There are no other values for this property defined in TTML2.

[palemieux]

Prohibit #textOrientation-sideways-LR in Text and Image profiles, and make no other change.

I believe this was the intent since #textOrientation is not a requirement.