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Re: unifying alternate content across embedded content element types

From: <w3c@appxweb.com>
Date: Wed, 18 Jul 2007 14:57:37 +1000
Message-ID: <20070718145737.nh312s9lw0co4owk@203.145.41.23>
To: public-html@w3.org

Reading the discussion the word "context" keeps coming up, which does
not appear to be adequately addressed by any of the alternate content
mechanisims, alt or longdesc etc. My suggestion is that
for the alternative content mechanism to have a chance of conveying
the meaning of the embedded content,  the primary context  needs to be  
  incorporated first, maybe as part of the alt/longdesc attribute with
the secondary context included as part of the attribute text.  The  
primary context could then be displayed prior the alt text.

As an example  take the two cases of the the W3C Valid XHTML 1.0
Transitional image below.

Case 1
<img src="../images/valid-xhtml10-blue.gif" alt="Valid XHTML 1.0
Transitional" height="31" width="88"/>

Case 2
<a href="http://validator.w3.org/check?uri=referer"
style="float:right;"><img src="../images/valid-xhtml10-blue.gif"
alt="Valid XHTML 1.0 Transitional" height="31" width="88"/></a>

In the first case the image is used as a icon to demonstrate the  
webpage is valid  XHTML 1.0 and in the second it does this as well as  
providing a
mechanism to validate the page (by clicking the image link). The alt  
text  "Valid XHTML 1.0 Tansitional" does not adequately convey the  
meaning of both of these cases  because the primary context is lost.   
Trialling my suggestion you could have a  small list of alt types eg  
for the img element  alt_icon, alt_button,alt_image, alt_graphic,  
alt_figure, alt_photo, alt_screenshot, alt_banner, alt_masthead.   
Applying this to the W3C Valid XHTML 1.0  Transitional image you would  
have:

alt_icon="Valid XHTML 1.0  Transitional"  rendered as  "Icon:Valid XHTML 1..0"

and

alt_button="Valid XHTML 1.0  Transitional"  rendered as "Button:Valid  
XHTML 1.0"

I have tried to mimic this on my website, for instance
http://www.appxweb.com/getting_started/getting_started.html
and it seems to work.

---
Ian Hart
Appxweb




Quoting Sander Tekelenburg <st@isoc.nl>:

>
> At 01:00 -0500 UTC, on 2007-07-15, Robert Burns wrote:
>
>> On Jul 15, 2007, at 12:13 AM, Sander Tekelenburg wrote:
>>> As an author, you should look at the entire document, without the
>>> images
>>> being loaded, and for each image consider what text would make
>>> sense in its
>>> place; what text would make you not miss the image, because that
>>> text conveys the same as the image. [...]
>>
>> It might be helpful if you too could provide some examples of what
>> you're saying. For example, in Jon's Fluffy picture example, how
>> would you populate the @alt attribute? [...]
>
> I'll try, now that I understand Jon's original point :) I think the problem
> is in part with the caption. IMO it would, exactly because it is a context
> thing, be entirely appropriate to adjust the caption such that it makes sense
> with either equivalent. this might be reasonable:
>
> [context: A page describing my cat, Fluffy, containing one picture]
> <img src=cat.jpg alt="Fluffy">
> <p>Playing with a ball of yarn</p>
>
> (This is not dissimilar to "<a>click here</a>", which may 'work' in context,
> but is useless without context. I think all of us do adjust our text now and
> then so that we can provide better link text.)
>
> But as said, it's entirely a contextual thing. If the context is both your
> cats Fluffy and Miles, then the above probably won't work, because you may
> need to let your audience know which cat you're conveying information about.
> So in that case, this might be more appropriate:
>
> <img src=cat.jpg alt="">
> <p>Fluffy likes playing with a ball of yarn</p>
>
> After all, if (*if*)) the entire message is already conveyed through the
> caption, then that fact means the is image purely decorative.
>
> This is why I usually try to avoid providing examples of proper @alt text. It
> quickly gets very subtle. If there is the slightest bit of confusion about
> the context, what makes the alt text 'right' may be misunderstood and
> incorrectly applied to a different context. It's better to work with real
> life cases. (But a lot more work...)
>
> [...]
>
>> Also to push this question, I've been trying to get across, why not
>> just always put that equivalent content in a document fragment
>> targeted by the @longdesc attribute and leave @alt off completely.
>
> I suppose that might make sense, in certain contexts. Maybe like this:
>
> [context: About my cat, Fluffy]
> <img src=cat.jpg alt="" longdesc="#id">
> <p id="id">Long, richly marked up, description of how Fluffy likes playing
> with balls of yarn</p>
>
>> After all, the @longdesc could be short or long? It can be markup
>> rich or not. It can be on the same page or on another page. Through
>> some CSS and DOM wizardry it can be made available in ways that
>> current UAs do not make available for any other fallback (at least by
>> default).
>
> CSS cannot be relied upon to be available, so access to content should not be
> made reliant on it. Same for "DOM wizardry", assuming you're talking about
> javascript.
>
>
> --
> Sander Tekelenburg
> The Web Repair Initiative: <http://webrepair.org/>
>
>
Received on Wednesday, 18 July 2007 19:12:14 GMT

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