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Change Proposal text for HTML WG ISSUE-122 (HTML5 section 4.8.1.1.7)

From: Gregory J. Rosmaita <oedipus@hicom.net>
Date: Thu, 11 Nov 2010 17:29:32 +0000
To: public-html-a11y@w3.org
Message-Id: <20101111172815.M32246@hicom.net>
aloha!

as documented in:

http://www.w3.org/html/wg/wiki/ChangeProposals/purely_decorative_images

in fulfillment of HTML WG Action 195, assigned to me at TPAC 2010:

http://www.w3.org/html/wg/tracker/actions/195

which seeks to close HTML WG Issue 122:

http://www.w3.org/html/wg/tracker/issues/122

here is the change proposal providing replacement text for section 
4.8.1.1.7 of HTML5

--- BEGIN CHANGE PROPOSAL ---

Text Describing Purely Decorative Images in HTML5


Summary

This change proposal addresses ISSUE-122 Lady of Shallott as example of 
purely decorative image.

This change proposal was composed in fulfillment of HTML WG ACTION-195: 
propose replacement example for lady of shallot example of purely 
decorative use of image with code example of one of the use cases 
provided in prose introducing the example

Rationale

Advice about providing alt text for "purely decorative images, and the 
definition thereof, should be contained in the HTML5: Techniques for 
providing useful text alternatives and the Web Content Accessibility 
Guidelines, version 2.0 (WCAG 2.0).

Details

Currently, HTML5 section 4.8.1.1.7 states:

    4.8.1.1.7 A purely decorative image that doesn't add any information

    ISSUE-31 (alt-conformance-requirements) blocks progress to Last Call

    In general, if an image is decorative but isn't especially 
    page-specific, for example an image that forms part of a site-wide 
    design scheme, the image should be specified in the site's CSS, not 
    in the markup of the document.

    However, a decorative image that isn't discussed by the surrounding 
    text but still has some relevance can be included in a page using 
    the img element. Such images are decorative, but still form part of 
    the content. In these cases, the alt attribute must be present but 
    its value must be the empty string.

    Examples where the image is purely decorative despite being relevant 
    would include things like a photo of the Black Rock City landscape 
    in a blog post about an event at Burning Man, or an image of a 
    painting inspired by a poem, on a page reciting that poem. The 
    following snippet shows an example of the latter case (only the first 
    verse is included in this snippet):

    <h1>The Lady of Shalott</h1>
    <p><img src="shalott.jpeg" alt=""></p>
    <p>On either side the river lie<br>
    Long fields of barley and of rye,<br>
    That clothe the wold and meet the sky;<br>
    And through the field the road run by<br>
    To many-tower'd Camelot;<br>
    And up and down the people go,<br>
    Gazing where the lilies blow<br>
    Round an island there below,<br>
    The island of Shalott.</p>


Replace With

4.8.1.1.7 A purely decorative image that doesn't add any information

If an image is decorative but isn't especially page-specific -- for 
example, an image that forms part of a site-wide design scheme -- the 
image should be specified in the site's or document's CSS, not in the 
markup of the document.

Exceptions to this rule, in cases where CSS cannot be used to display 
an entirely decorative image, are covered by the HTML5: Techniques for 
providing useful text alternatives. [HTML ALT TECHS] Authors are also 
encouraged to consult the Web Content Accessibility Guidelines 2.0 for 
more detailed information and acceptable techniques. [WCAG 2.0]


Impact

Positive Effects

    * Provides a single reference for "A purely decorative image that 
      doesn't add any information" by providing the correct usage guide 
      for "purely decorative images": define them using CSS;

    * Keeps such information in a single reference for developers and 
      authors; 

Negative Effects

    * none, since advice and guidance on providing appropriate alt text 
      is already contained in HTML5: Techniques for providing useful 
      text alternatives [HTML ALT TECHS]; 


Conformance Classes Changes

none


Risks

none


References

    * HTML5: Techniques for providing useful text alternatives
      http://dev.w3.org/html5/alt-techniques/

    * Web Content Accessibility Guidelines, version 2.0 (WCAG 2.0) 
      http://www.w3.org/TR/wcag20

--- END CHANGE PROPOSAL ---

OPEN QUESTIONS:

1. should the first paragraph of the replacement text contain a warning 
that it is not possible to annotate background images when using CSS?

2. [your question(s) here]

gregory.
--------------------------------------------------------------
You cannot depend on your eyes when your imagination is out of
focus.                                           -- Mark Twain
--------------------------------------------------------------
Gregory J. Rosmaita: oedipus@hicom.net
   Camera Obscura: http://www.hicom.net/~oedipus/
          Oedipus' Online Complex: http://my.opera.com/oedipus
--------------------------------------------------------------
Received on Thursday, 11 November 2010 17:30:01 GMT

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