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

From: Laura Carlson <laura.lee.carlson@gmail.com>
Date: Mon, 30 Sep 2013 12:53:08 -0500
Message-ID: <CAOavpvftVNKiX0KpBOKeHZrh99tkjsXh5QXQQEi_cUNVBnkOdA@mail.gmail.com>
To: public-comments-wcag20@w3.org, Charles McCathieNevile <w3b@chaals.com>
Cc: Andrew Kirkpatrick <akirkpat@adobe.com>, Joshue O Connor <joshue.oconnor@cfit.ie>, John Foliot <john@foliot.ca>
Dear WCAG WG,

Thank you very much for agreeing to provide on-page longdesc syntax in
order to help people understand how it works and what limitations
exist. I agree with the direction you are taking but suggest helping
authors to overcome any limitations by incorporating a end-point
solution into H45's verbiage and example as well as pointing out the
advantages of using a separate resource by changing:

QUOTE [1] [2]

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.

[On-page Example]

<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>

UNQUOTE

To:

QUOTE

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 using a separate resource for the description is that
it is easily reusable for multiple instances of the same image, it
does not add on-page visual clutter to the original document, and the
description's end-point is self evident. An advantage of providing the
description within the same page as the image is that all users can
access the description. A limitation of the on-page  method, as well
as in providing multiple descriptions on a single separate page, is
that current implementations supporting longdesc do not identify the
long description's end-point. Authors can solve this by providing a
well-formed description, which identifies the where the description
ends.

[On-page Example]

<img longdesc="thispage.html#desc"
 alt="Line graph of the number of subscribers"
 src="http://www.company/images/graph.png">
<div id="desc">
 <h3>Long Description: Line graph of the number of subscribers</h3>
 <!-- Full Description of Graph -->
 <p>Long description ends.</p>
</div>

UNQUOTE

Related Resources:

Description Available in a Separate Document Provides Efficiency
http://www.d.umn.edu/~lcarlson/research/constriants/separate-doc.html

Forced Visual Encumbrance Adds Visual Clutter
http://www.d.umn.edu/~lcarlson/research/constriants/visual-encumbrance.html

In addition WCAG WG may want to consider demonstrating to authors how
to provide an actual long description by replacing the comment: <!--
Full Description of Graph --> with markup.

For example:
http://www.d.umn.edu/itss/training/online/moodle_downloads/accessibility_104/examples/pages/graph2.html#desc

More longdesc Examples:

http://www.d.umn.edu/itss/training/online/moodle_downloads/accessibility_104/examples/long.html

http://www.d.umn.edu/itss/training/online/moodle_downloads/accessibility_104/104ex1_fixed.html#browsers_stats

http://www.d.umn.edu/itss/training/online/moodle_downloads/accessibility_104/104ex1_fixed.html#painting

Thank you.

Best Regards,
Laura

[1] http://www.w3.org/TR/2013/NOTE-WCAG20-TECHS-20130905/H45.html#H45-description
[2] http://www.w3.org/TR/2013/NOTE-WCAG20-TECHS-20130905/H45.html#H45-ex2


On 9/22/13, akirkpat@adobe.com <akirkpat@adobe.com> wrote:

>  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.
>



-- 
Laura L. Carlson
Received on Monday, 30 September 2013 17:55:16 UTC

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