Re: Coments - last call draft

At 5:08 PM +1000 4/1/05, Charles McCathieNevile wrote:
>On Fri, 01 Apr 2005 00:54:41 +1000, Glenn A. Adams <gadams@xfsi.com> wrote:
>[...]
>>>7. Style, and user styling
>>>
>>>Quite a lot of work went into CSS. It is also considered pretty normal
>>>to style XML with CSS.
>>
>>Quite a lot of work went into XSL FO as well, which, in turn, is based
>>on many CSS style properties.
>>
>>The WG decided fairly early to adopt XSL FO as our basic
>>layout/formatting model, partly because it addresses I18N issues better
>>than CSS2, and we didn't want to be delayed waiting on the finalization
>>of CSS3 in which I18N issues have been addressed. We also wanted to make
>>use of a strict XML encoding of style information to enable
>>transformations (I personally view this as a major negative for CSS in
>>an XML world.)
>
>On the other hand accessibility issues are not addressed by FO. It 
>is not at all clear how a user should expect to provide styling 
>rules to meet their particular needs, as is trivial using CSS for 
>text styling.

On the one hand, XSL FO does address accessibility through the 
link-to-source provision.
http://www.w3.org/TR/xsl/slice7.html#common-accessibility-properties

If DXFP does not emulate this, it should be considered.

On the other hand, CSS already arogates to itself the ability to 
supercede presentation
properties asserted inline in the source being styled.

>>>For accessibility purposes it is helpful to have something like the
>>CSS2
>>>Cascade rules (which represented a change from CSS1 for enhanced
>>>accessibility). It turns out that text is about the only area where it
>>>is easy for user styles to make sense, so it seems a shame that there is
>>>no mechanism anticipated by the spec for using CSS and takng advantage of
>>>the cascading of rules that are important to the user, where appropriate.
>>
>>In general, the WG has tried assiduously to avoid defining UA behavior.

There have been at least a few, conspicuous cases where this proved 
to be a mistake.
Notable are html4:any.accesskey and whether html4:img.alt or 
html4:any.title should
take on the role of an onMouseOver annotation (a.k.a. tooltip).

This has led the current conventional wisdom in the WAI (driven by
the experience of the User Agent Working Group) to seek that format
specifications be more forthcoming about behavior defaults. Note this
is a leaning, not a fully worked set of guidelines. Personally, I
feel that behavior defaults should be explicitly conditioned on
assumed delivery context conditions.

Al

>In this case I think it is a mistake. There are some cases where it 
>makes sense to describe what User Agents MUST, SHOULD and MAY do, 
>and this case might be one of them (since otherwise it maynoteven 
>get onto the radar ofmany developers, leading to a serious lack of 
>accessibility in practice).
>
>>>8. Timed text and sign language
>>>
>>Conceptually, there is certainly a relation between a signed media
>>object and a caption/subtitle media object, both of which are
>>alternative representations of information typically encoded in an audio
>>media object for hearing users. The focus of the TT WG has been on
>>defining a TT media object. Perhaps the SVG WG might be interested in
>>evaluating a specialized usage of SVG that would support a sign language
>>media object.
>
>Hmmm. I am not sure if it would be an SVG object or a real video 
>more often. Anyway, it is possible to put this stuff in with SMIL 
>without too much hassle (although the mechanism involves switching 
>on languages and I am not sure how well that is handled in the 
>muliple language case).

If a SMIL integration of the whole presentation is available, with
all media options laid out, the User Agent should be apprised of this.
Lacking this there is an html:link.rel value for alternatives to the
current media object. We should look over the metadata provisions in
the DXFP for how this would fit in.

Al

>>>(In other words, this could be done with a brief note in the
>>introduction
>>>or somewhere).
>>
>>Good idea.
>
>OK.
>
>cheers
>
>Chaals
>
>--
>Charles McCathieNevile                      Fundacion Sidar
>charles@sidar.org   +61 409 134 136    http://www.sidar.org

Received on Friday, 1 April 2005 14:41:24 UTC