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Re: Projection media type in fullscreen browser mode

From: Aryeh Gregor <Simetrical+w3c@gmail.com>
Date: Tue, 18 Aug 2009 10:11:28 -0400
Message-ID: <7c2a12e20908180711m67f22755ia01e0ae0b419f905@mail.gmail.com>
To: "Tab Atkins Jr." <jackalmage@gmail.com>
Cc: fantasai <fantasai.lists@inkedblade.net>, www-style@w3.org
On Mon, Aug 17, 2009 at 10:11 PM, Tab Atkins Jr.<jackalmage@gmail.com> wrote:
> Have you actually done any testing here?  Opera's fullscreen mode
> responds to *both* "screen" and "projection".  Anything you specify as
> applying to "screen" will still work just fine when Opera is
> fullscreened.  You can just *also* load special rules that only apply
> in fullscreen mode by wrapping them in a "@media projection" rule.

I did test.  I provided the test page in my first post.  Opera does
not respect screen stylesheets in full-screen mode -- at least in some
hard-to-control circumstances (see my response to Øyvind Stenhaug
below).

> If you're not using the projection media style, then it *does* do nothing.

"Using" meaning what, and "you" meaning who?  As an author, I've found
that Opera doesn't use screen stylesheets in some cases where I had no
intent to make my page projectable.  Googling "Opera projection" shows
that other authors have had the same experience.

> We had a discussion about a "page" value for "overflow" a while back.
> Nothing's come out of yet, but I definitely still think it's a great
> idea.  The only problem is dealing with the page-nav controls.  Are
> they auto-generated?  Where?  What do they look like?

I assume that just as the UA is responsible for creating scrollbars
for interactive continuous media, it's responsible for creating page
navigation controls for interactive paged media.

On Tue, Aug 18, 2009 at 5:17 AM, Øyvind Stenhaug<oyvinds@opera.com> wrote:
> To clarify, if the projection media type is used anywhere it will render to
> that media type and ignore "screen". If there is nothing projection-specific
> it will render to "screen" media.

Then Opera is deciding its media type partly based on the markup
provided by the author?  That's not how I expect media types to work
-- they're meant to query what sort of device is being used, not
return information about the current page's markup.

Pragmatically, for web applications that are meant to be distributed
to and used by third parties, this behavior is impossible to control.
I can't know if the administrator of the site has added a @media
projection rule somewhere in a custom stylesheet.  In MediaWiki, even
individual users can add custom stylesheets for themselves.  Plus
extensions, or even just different code paths I don't know about.  A
projection stylesheet might be added only on Tuesdays during the full
moon, for all I can be sure of.  But whether my stylesheet is loaded
in Opera full-screen mode depends on exactly that.

So the only way for MediaWiki to get correct behavior is to make sure
that *all* built-in stylesheets are served as screen,projection, to
make sure Opera uses them in full-screen mode no matter what.  Even
though we don't actually want them to be used for projection, and the
content is actually totally unsuitable for paged projection.  As soon
as anyone feels forced to label their stylesheets projection when they
don't actually intend to project, that means checking for the presence
of projection-specific rules isn't a very good heuristic anymore!

Now, in fact, if any MediaWiki extension/admin/etc. provides rules for
screen only, those rules will break, because we added projection
rules, because if we didn't then *our* rules might break . . .

I don't think this is good behavior, or that it follows the spec.
Received on Tuesday, 18 August 2009 14:12:09 GMT

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