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[Bug 8716] New: Replace img Guidance for Conformance Checkers with Suggested Text for Short Text Alternatives

From: <bugzilla@wiggum.w3.org>
Date: Mon, 11 Jan 2010 19:57:32 +0000
To: public-html-a11y@w3.org
Message-ID: <bug-8716-3290@http.www.w3.org/Bugs/Public/>
http://www.w3.org/Bugs/Public/show_bug.cgi?id=8716

           Summary: Replace img Guidance for Conformance Checkers with
                    Suggested Text for Short Text Alternatives
           Product: HTML WG
           Version: unspecified
          Platform: Macintosh
        OS/Version: All
            Status: NEW
          Keywords: a11y
          Severity: normal
          Priority: P2
         Component: HTML5 spec bugs
        AssignedTo: dave.null@w3.org
        ReportedBy: laura.lee.carlson@gmail.com
         QAContact: public-html-bugzilla@w3.org
                CC: ian@hixie.ch, mike@w3.org, public-html@w3.org, public-
                    html-a11y@w3.org


The current guidance for conformance checkers is unclear and does not implement
WAI CG's advice for short text alternatives.

For conformance checker guidance [1], please list out the required short text
alternative options that are required for images to be considered valid as
advised by WAI CG.

RATIONALE:

 * A succinct list would provide clarity of all valid options at a glance.
 * Since WAI CG condones a Flickr loophole, it should at least be included at
the element level, rather than the document level or it could be too easy for
authors just to tag the document and not bother with any alternative for
images.
 * Bug 8646 lists rationale for removing the email loophole.

DETAILS:

Replace the Current Text:

"A conformance checker must report the lack of an alt attribute as an error
unless either the conditions listed above for images whose contents are not
known apply, or the conformance checker has been configured to assume that the
document is an e-mail or document intended for a specific person who is known
to be able to view images, or the document has a meta element with a name
attribute whose value is an ASCII case-insensitive match for the string
'generator'."

With Suggested Text:

"A conformance checker MUST report the lack of a short text alternative as an
error. The img element is only valid when at least one of the following is
true:

 * alt is present (empty or non-empty) OR
 * @aria-labelledby is present (non-empty only) OR
 * the <img> is located within a <figure> that has a non-empty <legend> OR
 * @role="presentation"  OR
 * <img> has  an attribute other than alt whose value is an ASCII
case-insensitive match for the string 'generator'."

IMPACT:

 1. Would list validity options, to improve clarity.
 2. Would remove the email loophole. Please see bug 8646 for rationale [2].
 3. Would change the "generator" option from document level to element level,
to allow checking individual images.
 4. Would implement advice provided from the WAI CG [3]

CONFORMANCE CLASS CHANGES:

Create an attribute that allows a "generator" string per WAI CG advice, which
states:

<quote>
Recommendations regarding auto-generated alternative text

We have reached the following consensus concerning "automatically generated"
alternative text: In order to address both the validity and human generation
concerns, we do not oppose the creation of 'autogenerated' and 'missing'
attributes where either one of these could be used to make an image that does
not have any human-generated text alternatives valid. (Note: It is important
that this marker is not included in the alternative text string itself.)"
<unquote>

References

[1]
http://dev.w3.org/html5/spec/text-level-semantics.html#guidance-for-conformance-checkers
[2] http://www.w3.org/Bugs/Public/show_bug.cgi?id=8646
[3] http://www.w3.org/2009/06/Text-Alternatives-in-HTML5


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Received on Monday, 11 January 2010 19:57:35 GMT

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