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Right now, WebVTT specifies that text can be rendered vertically by using the "vertical" cue setting and a value of "rl" or "lr". This is mapped to the CSS specification of "writing-mode" with a value of "vertical-rl" or "vertical-lr". http://dev.w3.org/csswg/css3-writing-modes/ The CSS3 spec seems to default vertically rendered text's line orientation to the default one for that font, essentially leaving it to the browser whether to write text upright or sideways. My suggestion is therefore to require the CSS interpretation of "vertical" to also contain "text-orientation: upright" as the default. Then, we probably also need to introduce a cue setting for text-orientation to allow sideways rendering if needed.
Why are captions different than other text in Web pages here?
Hmm.. they are not. So, what I am missing is a way to specify whether vertically rendered text is rendered upright or sideways in WebVTT. We have no setting for that. It can only be changed with CSS, which is not sufficient. Can we add a cue setting of "text-orientation:upright/mixed/sideways-left/sideways-right" to be mapped to the appropriate text-orientation in CSS? http://dev.w3.org/csswg/css3-writing-modes/#text-orientation0
Why would you ever render it sideways? Isn't that just an esoteric presentational thing? I don't understand why CSS isn't enough here. HTML doesn't have a way to control this either.
(In reply to comment #3) > Why would you ever render it sideways? Isn't that just an esoteric > presentational thing? I'm not overly fussed about whether we add sideways, but I thought some of the examples at http://wiki.whatwg.org/wiki/Use_cases_for_timed_tracks_rendered_over_video_by_the_UA had sideways vertical fonts (I'm not good with chinese characters). Since it's up to the browser to pick whether a vertical font is rendered sideways or upright, I think we need to provide the Web Developer with the ability to choose. > I don't understand why CSS isn't enough here. HTML doesn't have a way to > control this either. HTML has CSS for this. WebVTT has to be usable without CSS.
HTML has to be usable without CSS too. And is. As is WebVTT. Rotating CJK ideographs makes about as much sense as rotating latin ones (which is to say: some, but it's esoteric), or changing the colour, or changing the font. I don't understand why HTML and WebVTT are different here. (If any browser implements the CSS 'text-orientation' property then please feel free to file a bug so that we add this to the list of allowed CSS properties.)