Edit comment LC-1574 for Device Independence Working Group

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Comment LC-1574
Commenter: Al Gilman <Alfred.S.Gilman@IEEE.org>

Resolution status:

I have to admit that discussions with CSS have shown that the 'em' unit is not
good for what we wanted to use it for: expressing the screen size in terms
of character count.

The suggestions from the CSS WG that we use a new constant that is defined
by the width of the zero character rather than the height of the
capital-em character
is supported by PFWG.


The discussion in CSS came from users of forms in mobile devices, not
from disability issues.

So the DI framework needs to be able to incorporate this degree of freedom to
make its market opportunity. We need to find a way to accelerate the
insertion of this new unit in profiles that are actually getting used, in CSS,
in CSS Media Queries, and in DISelect.

With the substitution of the zero-width for the reference length unit, in place
of the capital-em-height, I still believe that responding to this
metric of display
size is an accessability requirement and lacking it is a defect in
the functions library.

[for the record: do not accept disposition]


At 11:15 AM +0000 1/4/06, Roland Merrick wrote:
>Greetings Al, thanks for your comments on the content selection last
>call [1]. As part of this you include "The 'em' length unit".
>The DIWG assigned this comment the identifier Gilman-8
>This mail documents DIWG's response to your comments.
>DIWG Response
>DIWG agrees that access to metrics based on font size is desirable.
>However, the starter set functions merely replicate the capabilities
>of CSS Media Queries as currently defined. Since that is their
>declared purpose, it would be inconsistent to extend them.
>However, as is noted in the response to comment WAI-1, DIWG will
>expand the set of XPath functions to include more general mechanisms
>for access. Such functions would be capable of retrieving font-size
>based information if that is available in the delivery context.
>So, while DIWG declines to extend the starter set functions, we
>believe that other facilites will make this information available to
>authors if it is available within the delivery context.
>Regards, Roland
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