Re: [webvtt] 3.1 Line wrapping for non-Latin scripts [I18N-ISSUE-434]

Registered in https://www.w3.org/Bugs/Public/show_bug.cgi?id=28267 for
feedback by TextTracks CG.

Regards,
Silvia.

On Sat, Mar 21, 2015 at 7:49 AM, Phillips, Addison <addison@lab126.com> wrote:
> I18N comment: https://www.w3.org/International/track/issues/434
>
> 3.1 Text track cues
> http://www.w3.org/TR/2014/WD-webvtt1-20141111/#text-track-cues
>
> Line wrapping should take into account the special rules needed for scripts such as the following:
>
> - Chinese, Japanese and Korean wrap after characters, but don't put certain characters at the start/end of a line
>
> - Thai and other SE Asian scripts wrap at word boundaries, but words are not delimited by spaces – spaces are instead used to separate phrases.
>
> - Tibetan wraps after the tsek character that follows a syllable – words are not separated by spaces.
>
> - Indic and other complex scripts break at orthographic syllable boundaries, which are often two or more grapheme clusters.
>
> See http://www.w3.org/TR/css3-text/#line-breaking for additional background. (http://r12a.github.io/scripts/tutorial/part5 provides additional examples, if needed.)
>
> 6.2.1 says that "Text runs must be wrapped according to the CSS line-wrapping rules", but that is a little vague (and, to be honest, the CSS information on script behaviour is also somewhat sparse). No mention is made of default settings for the line-break and word-break properties.
>
> It would be good, as a minimum, to remind implementers that script-specific wrapping algorithms need to be supported for WebVTT content.
>
> (6.2.2 says that "the 'word-wrap' property must be set to 'break-word'". Note that a alternative, and somewhat more descriptive name for this property is overflow-wrap.)
>
> In addition, we noticed in:
>
> http://www.w3.org/TR/webvtt1/#cues-with-multiple-lines
>
> In Section 1.1, there is discussion about line-wrapping and line-breaking. The examples are given in English. "Balancing" line wrapping might take different forms because of the presentational needs of various langauges.
>

Received on Sunday, 22 March 2015 00:20:41 UTC