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Re: Braille media def'n (Was Re: accessibility review...)

From: Daniel Dardailler <danield@w3.org>
Date: Tue, 16 Sep 1997 12:26:06 +0200
Message-Id: <199709161026.MAA28064@www47.inria.fr>
To: "Pawson, David" <DPawson@rnib.org.uk>
cc: WAI Working Group <w3c-wai-wg@w3.org>

> 
> Jason wrote:
> 
> Thus, we need to make a decision, prior to having
> worked out the details of Braille CSS, and taking into account other
> style
> systems such as DSSSL, whether we need the line length and page depth
> parameters as part of the media type.
> 
> They _should_ not be part of the media definition.
> 
> If I want printed braille output today, on my work embosser
> which is huge, and smaller tomorrow on my home embosser
> all I should have to change is the style sheet in use.
 

I'm not sure Jason and yourself (all of us in fact) are not in violent
agreement.

There is one HTML source.

There are potentially multiple style sheet sources.

Right now, CSS defines style sheet properties for screen, and in the
next release for print and aural output.
Later on, extensions will be made for braille specific properties.

In the "normal" situation, I would expect HTML documents to only
include a reference to screen style properties (BTW 'screen' is now
the default SS media type, not 'all', thanks to Jason for pointing
that out to the WAI group, and to Bert Bos to raise it to the CSS
working group over the summer).

Something like

<HTML>
<HEAD> <TITLE> foo </TITLE>
<LINK rel=stylesheet media=screen href=foo.css>
</HEAD>
<BODY>
 ...
</BODY>
</HTML>

If I use a braille device of some kind as my user agent, then I can
override the style with my local braille CSS setting. Since the media
type in the document is 'screen', my braille setting should take over
(in terms of cascading priority) with no problem (providing I use the
correct media type in my agent)

The author of the document might also (but I don't expect that to be
the norm) want to specify a braille SS for her document:


<HTML>
<HEAD> <TITLE> foo </TITLE>
<LINK rel=stylesheet media=screen href=foo.css>
<LINK rel=stylesheet media=braille href=foob.css>
</HEAD>
<BODY>
 ...
</BODY>
</HTML>

In which case my braille local setting would be mixed with these
author-provided braille setting.

The SS media type is therefore important in deciding what exactly is
used as far as which styling is applied. 
Received on Tuesday, 16 September 1997 06:27:27 UTC

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