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Re: [css3-speech] :media-overlay-active

From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Thu, 9 Jun 2011 09:30:53 -0700
Message-ID: <BANLkTimkXmJDfUcMjYD87Q0przwiOxK53JAedyaCD58yotwDqw@mail.gmail.com>
To: fantasai <fantasai.lists@inkedblade.net>
Cc: "www-style@w3.org" <www-style@w3.org>
On Wed, Jun 8, 2011 at 10:12 PM, fantasai <fantasai.lists@inkedblade.net> wrote:
> The EPUB3 spec includes the definition for a pseudo-class to select elements
> that are active during speech playback:
>  http://epub-revision.googlecode.com/svn-history/trunk/build/30/spec/epub30-mediaoverlays.html#sec-docs-assoc-style
>
> There's some ongoing discussion in the EPUBWG about prefixing the
> pseudo-class
> name or using a reserved class name instead of a pseudo-class, etc.
>  http://groups.google.com/group/epub-working-group/browse_thread/thread/1eba33a3b544b6e2

If epub is supposed to play nicely with other web content, then
reserved class names are a no-no.  The entire *point* of pseudoclasses
is that they are reserved class names, so the class attribute remains
entirely in author's hands.  It doesn't make any sense to try and do a
reserved class name instead of a pseudoclass; it would be like trying
to make a "super-class" that was restricted to only a single element
and had higher specificity, instead of just using an ID.


> Their spec's a little underdefined, imo, but I thought such a pseudo-element
> would
> be something for the CSSWG to consider, particularly as an addition to CSS3
> Speech.
> The state should propagate up to ancestors, so that you can choose, for
> example,
>
>  p:media-overlay-active { outline: solid yellow; } /* ugly example for demo
> purposes */
>
> I'd suggest coming up with a less awkward name, though. :) (Maybe
> :playback-active?)

As Daniel suggests, this concept is vaguely similar to the cue format
used in WebVTT, though Daniel's objections to just reusing ::cue() are
correct: captions are linear in nature and thus have a sensical notion
of 'past' and 'future' that the DOM doesn't always have; and WebVTT
simply automatically shows the current cue and hides the inactive
ones, without giving the author an opportunity to style the inactive
cues in any way.

Still, though, we could potentially plumb it for names/concepts.
Perhaps :active-cue?

~TJ
Received on Thursday, 9 June 2011 16:31:40 GMT

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