Re: WebVTT Horizontal writing direction


Thank you for your clarification.

I had seen the possibilty to use escape ‎ and ‏

Without a equivalent to "vertical:rl" for horizontal text,
is it an issue when using "align:" setting ?

for vertical writting

    vertical:rl   vertical:lr
"align:start"  top    top
"align:middle"  centred vertically  centred vertically
"align:end"  bottom    bottom

for horizontal writting
           "RtL"   "LtR"
"align:start"  left     right
"align:middle"  centred horizontally   centred horizontally
"align:end" right     left

And same for "position:" cue setting

"position:start" is left for horizontal writting LtR
"position:start" is right for horizontal writting RtL

I am not a I18N expert, but I am unclear who to solve this,
for exemple see the TTML Example
Rendition – Unicode Bidirectionality

Another solution would be the use of a class with direction CSS properties:
.rtl {
     direction: rtl;
     unicode-bidi: bidi-override;

But these CSS properties aren't allowed to apply to the '::cue' 


On 05/02/2015 04:11, Philip Jägenstedt wrote:
> To get RTL you simply use a cue text which is RTL according to the
> BiDi algorithm, and you can use ‎ and ‏ to where necessary in
> mixed-directionality text.
> Note, however, that the equivalent to vertical:rl for horizontal text
> would be control over which direction additional lines of texts grow,
> up or down. We don't have explicit control over that, even though the
> cue placement algorithm does move whole cues up or down.
> Philip
> On Wed, Feb 4, 2015 at 11:39 PM, Thierry MICHEL <> wrote:
>> Hi,
>> WebVTT lastest draft [1]
>> 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]

Received on Thursday, 5 February 2015 13:26:38 UTC