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MEDIA discussion (-starter DRAFT)

From: Al Gilman <asgilman@access.digex.net>
Date: Thu, 16 Oct 1997 14:05:15 -0400 (EDT)
Message-Id: <199710161805.OAA28798@access2.digex.net>
To: w3c-wai-hc@w3.org (HC team)
Cc: jbrewer@w3.org
I got a special dispensation from Judy that this one could lag
a bit, as it got added to the list of prime topics at the eleventh
hour.  I will send this on to the IG this evening.  Please squawk
if you see any hairs out of place. 

-- Al


MEDIA     Classifying user display and control


It is possible to associate a stylesheet with the medium or media
that it is intended to be used with.  One of the key purposes of
the division of labor between HTML and CSS is so that core
content can be in one HTML document and multiple stylesheets can
split out stylistic details appropriate to one or another of
screen, audio, etc. media.

Today there is a simple list of media kinds and you pick one.
This is not enough information, as the HC group sees it, to keep
stylists happy.  More information is also desirable to guide the
selection among a range of stylesheets when different stylings
are designed for quantitatively different variants of on kind of

In graphical applications such as presentation graphics it is not
enough to know that the material is to be projected to make final
styling choices.  Stylists will want to know the precise size of
the display region in pixels, and the range of colors available.

The same it true for Braille applications where styling for
interactive use with a refreshable Braille display will want to
differ somewhat from that used to dump a document to hardcopy
with a Braille embosser.


The list of pre-defined media types in the HTML specification
should be expanded to include one, named "console" or "tty" or
something like that, to cover character-mode terminals which
includes ANSI and VT-100 terminals, the console mode in windowing
environments, and also terminals which operate in line-by-line
mode such as the TTD devices used by the deaf.

The list should also be made open-ended, so that usage can

Issues of how much to tell a server about the conditions at
the client end, and how to encode that in HTTP still merit
further study, as does the development of a richer capabilty
for indicating the display and control media in more detail
in information controlling the application of stylsheets.


There are various questions worth discussing in this area.  For

Is it better to use the disability-specific names such as Braille
and speech which will be clearly recognized as carrying a moral
obligation, or to use less catchy names such as tty and audio
which capture a larger pool of users and hence would have more
market pull to get them used?  (An one-row by twenty-cell
refreshable Braille display is a low-end tty device with roughly
the display capbility of a four-row by sixteen-cell liquid
crystal display on a personal digital assistant).

Similarly, is Braille embossing more like interactive Braille for
stylesheet purposes, or more like printing to a tty-like device?


Please discuss this issue by sending email to w3c-wai-ig@w3.org .
Include the symbol MEDIA in the subject heading of your
message, to help other subscribers organize the volume of mail we
hope this will generate.

----- End of forwarded message from Al Gilman -----
Received on Thursday, 16 October 1997 14:05:35 UTC

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