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Re: "image analysis heuristics" (ISSUE-66)

From: Maciej Stachowiak <mjs@apple.com>
Date: Sat, 06 Feb 2010 17:16:35 -0800
Cc: "public-html@w3.org" <public-html@w3.org>
Message-id: <D1175550-0F90-4E11-8DE8-0528CE5FB5F7@apple.com>
To: Lachlan Hunt <lachlan.hunt@lachy.id.au>

On Feb 6, 2010, at 2:52 AM, Lachlan Hunt wrote:

> I'm not concered about the specific wording used, I'm generally happy for editors to phrase things in their own way.  I think what might be most productive here is that, instead of us trying to lock down and agree on specific wording, we should come up with a list of objective criteria to evaluate the any text Hixie writes in the spec related to this issue.

Thanks for getting this down to concrete points that we can evaluate objectively. If we can all agree on even a subset of these points, then I think that would be really useful, even if there are remaining points of disagreement.

 - Maciej

> Since there appears to have been a general agreement about what I previously suggested, excluding the list of techniques, it seems useful to compare my suggestion with the current spec text.  For reference, here is what I suggested earlier, minus the list of techniques:
> ---
> When the user is unable to make direct use of the image, e.g. due to a
> visual disability or because they are using a text terminal with no
> graphics capabilities, user agents may also provide the user with the
> ability to obtain any other information about the image that may assist
> the user in understanding its content or purpose, utilising any
> available repair technique.
> For more information, refer to the User Agent Accessibility Guidelines
> techniques for repairing missing content ([UAAG10-TECHS], section 2.7).
> ---
> And here is the current spec text:
> ---
> User agents may also apply heuristics to help the user make use of the image when the user is unable to see it, e.g. due to a visual disability or because they are using a text terminal with no graphics capabilities. Such heuristics could include, for instance, optical character recognition (OCR) of text found within the image.
> Warning! While user agents are encouraged to repair cases of missing alt attributes, authors must not rely on such behaviour. Requirements for providing text to act as an alternative for images are described in detail below.
> ---
> I think the warning to authors about not relying on repair techniques is non-objectionable, and may be left as is.
> Based on the discussion, I've come up with the following proposed criteria:
> 1. Permits user agents to apply any repair technique
> 2. Does not list specific techniques.
> 3. Informatively references the techiques described in UAAG (either 1.0
>   or the 2.0 draft)
> 4. The text is located in a section dedicated to describing
>   implementation requirements and is clearly distinguished from
>   authoring requirements.
> 5. Does not imply the use of futuristic technologies.
> 6. Does not imply that any technique can reliably determine author
>   intent.
> 7. Indicates that it is about providing additional information about the
>   image, which may help the user to understand the image's content or
>   purpose.
> (If I've missed any, or included any that I shouldn't have, feel free to comment or make adjustments)
> To understand what exactly is wrong with the current spec text, it would be useful for people who are objecting to it, to clearly describe how it fails to meet any of these criteria.
> In my own view, the current text fails #2 by mentioning OCR, #3 by not referencing UAAG; partially fails #5 by mentioning "heuristics" without clearly describing what would or would not be classified as such, and also fails #7.
> I also believe the location of the text in the current spec is acceptable, as it is in the section describing implementation requirements for images.  This is consistent with where implementation requirements are placed for every other element in the spec and should not be treated any differently.  I strongly disagree with Matt about moving this text to the Web Browsers section, where it has no relevance to anything else in that section.
> -- 
> Lachlan Hunt - Opera Software
> http://lachy.id.au/
> http://www.opera.com/
Received on Sunday, 7 February 2010 01:17:09 UTC

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