[html4all] Object element support

[Robert J Burns]

HI Jason,

I'm not sure you're saying anything that disagrees with what I'm  
proposing. Let me explain further.

On Aug 23, 2008, at 1:14 PM, Jason White wrote:

> On Sat, Aug 23, 2008 at 12:21:54PM +0300, Robert J Burns wrote:
>> That important difference is that one mechanism is for alt text —  
>> text
>> that is to be replaced and serve as a seamless replacement for the
>> embedded media — and the other mechanism is for descriptive text
>> equivalents — text that is a subject or visual description of the
>> embedded media not necessarily suitable to replacing the media in the
>> present document.
>
> An alternative approach, which I favour, is to collapse this  
> distinction by
> holding that there is only one alternative needed, namely, whatever  
> can serve
> as a seamless substitute for the embedded media. Either this  
> substitute is
> adequate to fulfill the purpose or convey the information served by  
> the media
> in the context of the content, or it is not.

I agree 100%. This is what I would refer to (following WCAG) as alt  
text. In other words I agree that "there is only one alternative  
needed", however, there is a need for authors to provide other text  
equivalents (not alt text) for users who want more.

> In the first case, any additional description would be superfluous.  
> In the
> second case, the alternative needs to be more explanatory or  
> descriptive, as
> appropriate, so as more adequately to serve as a substitute for the  
> embedded
> media.
>
> This is the premise on the basis of which WCAG 1.0 and 2.0  
> requirements are
> defined.
>
> I also disagree with the claim, introduced earlier in this thread,  
> that there
> are two categories of users, one of which would supposedly be served  
> by the
> seamless substitute, and the other of which would need, or benefit  
> from, the
> additional description.

I did not introduce a claim that there are two categories of users.  
Rather what I'm saying is that there are two categories of text  
equivalents: one being a descriptive equivalent (as opposed to alt  
text equivalent) that any given user might or might not want to access  
at their discretion. I further feel that by collapsing these two text  
equivalents into one we encourage authors to pollute the alt text with  
descriptive text equivalents that are a distraction for the users who  
don't want that. It may be that this also implies reveals two  
categories of users — those interested in descriptive equivalents and  
those who are not — but that's not the focus of my proposal here.

> To the contrary, there is one category of users,
> namely those whose delivery context precludes viewing or listening  
> to the
> embedded media, whether temporarily, as may be due to environmental or
> technological circumstances, or permanently, in the case of the  
> user's having
> a disability. However, the circumstances giving rise to the need  
> don't alter
> the nature of that need, namely for a seamless and adequate  
> substitute.

Again, I agree 100%. This refers to what I, according to my reading of  
WCAG, call alt text.

> While I appreciate the thinking that underlies Rob's distinction, I  
> don't find
> it compelling and I don't think it should serve to influence markup  
> language
> design. Moreover, WCAG does not draw such a distinction, and I would  
> argue
> that it should not.

I read WCAG as indeed drawing such a distinction (see 'Techniques for  
checkpoint 1.1'[1] and 'Long descriptions for images'[2] for example),  
though it is not stated as clearly as I think it should be to help  
authors compose adequate alt text.

> With apologies for entering the discussion purely to make a negative  
> point, I
> nonetheless hope this contrary view helps more than it hinders.
>
> To explain a little further, I think it is a matter of style on the  
> part of
> the author whether to provide a seamless substitute "in place", or  
> whether to
> provide part of that substitute - a label or a brief explanation -  
> in place,
> and then to include a link to additional details that give the missing
> explanatory or descriptive material.
>
> I earlier argued that if the substitute is adequate, then additional
> description is superfluous. It may be useful to provide such a  
> description,
> but it is not an accessibility requirement to do so - if it were,  
> then the
> supposed substitute would be inadequate as a genuine alternative to  
> the media.

I know this is your view on descriptive equivalent text. However, I  
think other users hold different opinions regarding descriptive  
equivalent text. Some users want access to more text equivalent than  
should be expected within strictly alt replacement text. So while  
there may be authoring styles (as opposed to the use of the term  
'style' with regard to presentation) that handle this issue  
differently, it would be far better for users and author for HTML to  
provide specific mechanisms and specific advice on how to separate  
these text equivalents.

Again, consider the earlier example I provided[3] where the alt text  
and the descriptive text are clearly separate. In that example, I  
failed to notice that the referenced image (as the sole contents of an  
anchor element) should have likely had its alt set to "fullsize image  
of coal power plant" (though similar guidance appears later in the  
figure caption). In any event the role of the photograph in this  
example is not quite decorative, but it also does not serve the same  
integral purpose to the meaning of the document as of a bar graph or  
other images where the alt text is crucial. It is perhaps best  
described as illustrative or even tangential to the thrust of the  
article. The alt text could be:

"a coal power plant silhouetted along a waterway with the dusk sunset  
(or dawn sunrise) in the background. The plant is spewing smoke and  
steam into the air and we can see the conveyor that delivers coal to  
the plant."

but I'm not sure that such a text equivalent is really appropriate in  
this particular case. It is a good descriptive text equivalent, but  
"fullsize image of coal power plant" might be more appropriate as the  
alt text for this anchor element image.

My sense is that if authors consistently used these two mechanisms  
they way I'm suggesting, a user like you (Jason) would typically avoid  
the descriptive text equivalent and rely only on the alt text  
equivalent, while other users I've discussed this with would prefer to  
query the UA for the descriptive text equivalent when further curious  
about the media. My feeling is that these distinctions exist whether  
we acknowledge them or not. And I am very concerned the attempt to  
gloss over these distinctions contributes to the continued difficulty  
authors have in composing sufficient alt text.

Take care,
Rob

[1]: <http://www.w3.org/TR/WAI-WEBCONTENT-TECHS/#tech-text-equivalent>
[2]: <http://www.w3.org/TR/WCAG10-HTML-TECHS/#long-descriptions>
[3]: my earlier email regarding the text equivalent distinctions <http://wilbur.bytowninternet.com/mailman/private/list_html4all.org/2008-August/000939.html 
 > regarding a random blog I ran across <http://interestingenergyfacts.blogspot.com/ 
 >