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Re: Techniques for WCAG 2.0 H45 longdesc: Missing on-page description example ( LC-2791)

From: <akirkpat@adobe.com>
Date: Sun, 22 Sep 2013 14:46:17 +0000
Message-Id: <E1VNkvR-0002MY-Cy@jessica.w3.org>
To: Laura Carlson <laura.lee.carlson@gmail.com>
Cc: public-comments-wcag20@w3.org,Charles McCathieNevile <w3b@chaals.com>
 Dear  Laura Carlson ,

The Web Content Accessibility Guidelines Working Group has reviewed the
comments you sent [1] on the Last Call Working Draft [2] of the Techniques
for WCAG 2.0 published on 11 Jul 2013. Thank you for having taken the time
to review the document and to send us comments!

The Working Group's response to your comment is included below.

Please review it carefully and let us know by email at
public-comments-wcag20@w3.org if you agree with it or not before 2 Oct
2013. In case of disagreement, you are requested to provide a specific
solution for or a path to a consensus with the Working Group. If such a
consensus cannot be achieved, you will be given the opportunity to raise a
formal objection which will then be reviewed by the Director during the
transition of this document to the next stage in the W3C Recommendation
Track.

Thanks,

For the Web Content Accessibility Guidelines Working Group,
Michael Cooper
W3C Staff Contact

 1.
http://www.w3.org/mid/CAOavpvf05d2iRAvPi9i13MmCW_MxXv7C9HkhvBga8H3iSAtL-A@mail.gmail.com
 2. http://www.w3.org/WAI/GL/2013/WD-WCAG20-TECHS-20130711/


=====

Your comment on H45: Using longdesc:
> 1. Title of the document
> 
> H45: Using longdesc
> 
> 2. Location within the document
> 
> "Examples"
>
http://www.w3.org/WAI/GL/2013/WD-WCAG20-TECHS-20130711/H45.html#H45-examples
> 
> 3. Concern
> 
> H45 is missing example longdesc syntax for an on-page description. If
> the long text alternative of an image is useful to all users, keeping
> it in plain view in the same document and using longdesc for screen
> reader users to programmatically obtain it is a good option. That way
> everyone can read it.
> 
> 4. Suggested change
> 
> Add something like:
> 
> If the long text alternative of an image is useful to all users,
> keeping it in plain view in the same document and using longdesc for
> screen reader users to programmatically obtain it is a good option.
> That way everyone can read it. By using a fragment identifier,
> longdesc may be used to link to a description within the same
> document. The syntax is:
> 
> <img
>  longdesc="#desc"
>  alt="Line graph of the number of subscribers"
>  src="http://www.company/images/graph.png">
> <div id="desc">
>  <!-- Full Description of Graph -->
> <div>
> 
> 4. Additional rationale for the comment
> 
> This technique is specified in the HTML5 Image Description Extension
> (longdesc).
> 
> Use Case:
> "Linking to a description included within a page
> If an image already has a description included within a page, making
> the linkage explicit can provide further clarity for a user who is not
> able to interpret the default layout. For example this happens when
> users force a re-layout of the page elements because they have
> magnified the content, or because they do not see the default visual
> relationship between the element and its description.
> This practice also enables description to be provided for all users.
> By keeping the association clear the content maintainer can more
> easily check that the description and link are actually correct."
>
http://dvcs.w3.org/hg/html-proposals/raw-file/default/longdesc1/longdesc.htm#use-cases
> 
> Example:
>
http://dvcs.w3.org/hg/html-proposals/raw-file/default/longdesc1/longdesc.html#intro
> 
> Please add an explanation and example to Techniques for WCAG 2.0
> document H45.
> 
> Thank you.


Working Group Resolution (LC-2791):
Thank you for your comment.  

The WG agrees that an example detailing this method may help people
understand how this works and what limitations exist. We will add an
additional paragraph to the description and example 2 will be added as
follows:
[DONE] description new second paragraph:
Authors can provide a description for an image by including text in a
separate resource or within the text of the page containing the image.  An
advantage of providing the description within the same page as the image is
that all users can access the description.  A limitation of this method, as
well as in providing multiple descriptions on a single separate page, is
that current implementations supporting longdesc read all text on the page
that follows the start of the long description. As a result, an end user
may hear the long description and all content on the page following it,
without knowing where the long description is intended to end unless
authors provide text to help users identify the end-point of the
description.

[DONE] Example 1: Using longdesc to refer to a long description contained
on a separate resource. (title of example changed to clarify)

[DONE] Example 2: Using longdesc to refer to a long description within the
same page.

<img longdesc="thispage.html#desc" alt="Line graph of the number of
subscribers" src="http://www.company/images/graph.png">
<div id="desc">
 <!-- Full Description of Graph -->
<div>

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Received on Sunday, 22 September 2013 14:46:18 UTC

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