WebVTT Horizontal writing direction

Hi,

WebVTT lastest draft [1]
http://www.w3.org/TR/2014/WD-webvtt1-20141113/
specifies the WebVTT vertical text cue setting

A WebVTT vertical text cue setting configures the cue to use vertical 
text layout rather than horizontal text layout. Vertical text layout is 
sometimes used in Japanese, for example. The default is horizontal layout.

vertical values:
- vertical:rl  writing direction is right to left
- vertical:lr  writing direction is left to right


My issue is how can one set writing direction  "right to left" for 
horizontal text ? (example of arabic lang)
I couldn't find explicit mention in the spec.
like:
- horizontal:rl  writing direction is right to left
- horizontal:lr  writing direction is left to right


Thierry

  [1] http://www.w3.org/TR/2014/WD-webvtt1-20141113/

Received on Wednesday, 4 February 2015 16:40:08 UTC