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Re: Braille media type

From: Al Gilman <asgilman@access.digex.net>
Date: Fri, 17 Oct 1997 22:26:33 -0400 (EDT)
Message-Id: <199710180226.WAA11522@access2.digex.net>
To: w3c-wai-ig@w3.org
to follow up on what Jason White said:

> 
> I hope that Al was not suggesting that the media type of BRAILLE be
> abandoned in favour of TTY.
> 

I think that there are pros and cons both ways.

In my mind it is a question of what are the major differences and
what are the minor differences.  If one considers that the
braille alphabets can be described by a character-set parameter
outside of the styling, then modulo character set a braille
display or embosser is only slightly different from its peers in
the character-grid group as opposed to widely different from
pixel-grid media whether screen or laser print.

To fully characterize a Braille device as a display medium I
believe you would have to indicate the size of the character
grid, the character set (braille alphabet) used, and whether it
is a dynamic refreshable display or a hardcopy write-once medium.
Thus I need charset and size parameters beyond a TTY base type,
and a "print" or "dynamic" modality.

Calling this a variant of a TTY media type is plausible.  And
possibly economically smart.

A stylesheet designed for a generic character-grid medium would
work reasonably well for Braille page formatting.  A stylesheet
designed for a laser printer probably would not.

You can still create another stylesheet that is even better for
Braille.  And it will be used at the right times if the
stylesheet selection algorithm knows to look beyond the base type
in the media indication before finally resolving what stylesheet
to use.

I am not assuming that authors will create only one stylesheet
per base type.  That is the point about presentation graphics.
One doesn't use the same button GIFs on a big (number of pixels)
projection device as one does on a small one.  The projection
medium, at least, will find people re-styling for parametric
differences in the medium.

If Braille is a base type in the media list, then you can still
borrow a TTY stylesheet when there is no Braille stylesheet.  You
just have to make your stylesheet picking process smart enough to
do that.  It probably just costs you a manual step.  When there
is no compatible stylesheet that goes with the document you want
to browse, the browser would ask you for what stylesheet you want
to use and you should get to choose either the author's TTY
stylesheet or your local Braille stylesheet.

Whether you call Braille a base type or you bury it in the
broader tty class, the available styles to the user are exactly
the same.

I don't want the Braille community to overlook existing
adaptation capabilities such as character set and language
parameters as they craft a complete Braille solution.  If we can
approach Braille as a class of variant sub-languages, we can
probably adapt for it more economically than if we think it is a
totally unique problem.  That is the important point.

If we can do that part right what you call it is not my primary
concern.

-- Al Gilman
Received on Friday, 17 October 1997 22:26:55 GMT

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