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Bug 9217 - Remove the Paragraph-Section-Heading loophole for not providing a text alternative.
Summary: Remove the Paragraph-Section-Heading loophole for not providing a text altern...
Status: CLOSED FIXED
Alias: None
Product: HTML WG
Classification: Unclassified
Component: pre-LC1 HTML5 spec (editor: Ian Hickson) (show other bugs)
Version: unspecified
Hardware: PC All
: P1 normal
Target Milestone: ---
Assignee: Ian 'Hixie' Hickson
QA Contact: HTML WG Bugzilla archive list
URL: http://dev.w3.org/html5/spec/text-lev...
Whiteboard:
Keywords: a11y, a11y_text-alt
Depends on: 8171
Blocks: 8716
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Reported: 2010-03-08 16:43 UTC by Laura Carlson
Modified: 2010-12-07 16:27 UTC (History)
7 users (show)

See Also:


Attachments

Description Laura Carlson 2010-03-08 16:43:35 UTC
SPEC SECTION:

Images whose contents are not known [1] 

BUG DESCRIPTION:

The third bullet: "The img element is part of the only paragraph directly in its section, and is the only img element without an alt attribute in its section, and its section has an associated heading" seems to be an unnecessary loophole for not providing a text alternative as well as unnecessarily complex for tools and authors.

Is there any rationale for this loophole?

Please remove this exception. 

REFERENCES:

http://dev.w3.org/html5/spec/text-level-semantics.html#unknown-images [1]

HTML5 ISSUE AND CHANGE PROPOSAL:

This is associated with HTML TRACKER ISSUE-31 
http://www.w3.org/html/wg/tracker/issues/31

Change Proposal: Replace img Guidance for Conformance Checkers:
http://www.w3.org/html/wg/wiki/ChangeProposals/ImgElement20090126
Comment 1 Maciej Stachowiak 2010-03-23 06:20:43 UTC
Requesting expedited processing of this bug on behalf of the HTML WG.
Comment 2 Ian 'Hixie' Hickson 2010-03-23 09:38:48 UTC
The idea here is that this should be conforming (if generated by a photo album site):

   <section>
    <h1>My ducks</h1>
    <img src="photo001.jpeg">
   </section>

...in the same way that this is:

   <figure>
    <figcaption>My ducks</figcaption>
    <img src="photo001.jpeg">
   </figure>

...or this is:

   <img src="photo001.jpeg" title="My ducks">

...because they all essentially have the same semantics: an image with a label.

Why would this be bad?
Comment 3 Maciej Stachowiak 2010-03-23 09:42:00 UTC
(In reply to comment #2)
> The idea here is that this should be conforming (if generated by a photo album
> site):
> 
>    <section>
>     <h1>My ducks</h1>
>     <img src="photo001.jpeg">
>    </section>
> 
> ...in the same way that this is:
> 
>    <figure>
>     <figcaption>My ducks</figcaption>
>     <img src="photo001.jpeg">
>    </figure>
> 
> ...or this is:
> 
>    <img src="photo001.jpeg" title="My ducks">
> 
> ...because they all essentially have the same semantics: an image with a label.
> 
> Why would this be bad?

Why the allowance for "is part of the only paragraph" instead of "is the sole content of the only paragraph"?

Comment 4 Ian 'Hixie' Hickson 2010-03-23 09:47:04 UTC
Well in none of the above examples is it the only thing in the paragraph, for example. They all have whitespace. But I could make it have to be the only non-whitespace content in the paragraph if that would satisfy the concern here.
Comment 5 Maciej Stachowiak 2010-03-23 09:53:01 UTC
(In reply to comment #4)
> Well in none of the above examples is it the only thing in the paragraph, for
> example. They all have whitespace. But I could make it have to be the only
> non-whitespace content in the paragraph if that would satisfy the concern here.

I don't know if it would satisfy Laura's concern fully, but I am curious what the use case for that is, if any. It seems like a bad feature to allow non-whitespace content in the paragraph, since that way you could have a single-paragraph section with an embedded image (perhaps floated), and then the validator would not catch the error that you forgot to omit alt. It is likely that in such a case, the section heading would not be a good text alternative for the image.
Comment 6 Maciej Stachowiak 2010-03-23 09:56:15 UTC
(In reply to comment #5)
> (In reply to comment #4)
>
> I don't know if it would satisfy Laura's concern fully, but I am curious what
> the use case for that is, if any. It seems like a bad feature to allow
> non-whitespace content in the paragraph, since that way you could have a
> single-paragraph section with an embedded image (perhaps floated), and then the
> validator would not catch the error that you forgot to omit alt. It is likely
> that in such a case, the section heading would not be a good text alternative
> for the image.

Er, I meant to say "forgot to include alt" rather than "forgot to omit".
Comment 7 Ian 'Hixie' Hickson 2010-03-25 01:07:37 UTC
Laura, please clarify if the suggestion above would satisfy your request. Thanks!
Comment 8 Ian 'Hixie' Hickson 2010-04-02 01:38:50 UTC
Laura?
Comment 9 Maciej Stachowiak 2010-04-11 11:16:54 UTC
I discussed this some with Mike Smith, from the perspective of implementing this rule in validator.nu, and also the perspective of implementing the corresponding accessibility code in WebKit to associate this kind of caption with. Our conclusions:

1) It's pretty hard to implement the rule (either the original version or the modified "only non-whitespace content in the only paragraph" variant) in a validator - it is quite complicated and unlike anything else the validator does. You pretty much have to implement the full HTML5 outline algorithm rule to handle this one exemption to the alt requirements.

2) For similar reasons, it would be hard to implement the corresponding code in a browser engine's accessibility mappings. WebKit currently has no foreseeable reason to implement the outline algorithm, but would need to do so solely to determine what is "the sole paragraph in a section".

3) Even if this really tricky code was written in validators and browser engines, it would likely be buggy because the rule is complicated to handle correctly.

4) The use case for this exception is adequately handled by <figure>.

Therefore, I think it would be best to remove this case from the set of conditions where omitting alt is allowed.
Comment 10 Ian 'Hixie' Hickson 2010-04-13 08:33:24 UTC
EDITOR'S RESPONSE: This is an Editor's Response to your comment. If you are satisfied with this response, please change the state of this bug to CLOSED. If you have additional information and would like the editor to reconsider, please reopen this bug. If you would like to escalate the issue to the full HTML Working Group, please add the TrackerRequest keyword to this bug, and suggest title and text for the tracker issue; or you may create a tracker issue yourself, if you are able to do so. For more details, see this document:
   http://dev.w3.org/html5/decision-policy/decision-policy.html

Status: Accepted
Change Description: see diff given below
Rationale: The complexity argument is a fair one.
Comment 11 contributor 2010-04-13 08:34:32 UTC
Checked in as WHATWG revision r5026.
Check-in comment: Remove the rule that says you can use the heading of a secton as the caption of an image that otherwise lacks alternative text.
http://html5.org/tools/web-apps-tracker?from=5025&to=5026
Comment 12 Laura Carlson 2010-08-18 13:08:35 UTC
Thanks for removing this exception.
Comment 13 Martin Kliehm 2010-12-07 16:27:52 UTC
Since this bug is verified closed, the bug-triage sub-team doesn't think it's accessibility task force priority any longer.