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Re: RE: Agenda + [2.4] CORRECT version of 2.4 proposal

From: John M Slatin <john_slatin@austin.utexas.edu>
Date: Thu, 5 May 2005 11:09:39 -0500
Message-ID: <6EED8F7006A883459D4818686BCE3B3B0124836D@MAIL01.austin.utexas.edu>
To: <w3c-wai-gl@w3.org>

Alex expressed concern that moving the SC about reading order to GL 2.4 L1 SC2 (as proposed by Yvette) would put to much burden on the content author to define a sequence.  He also wanted examples of situations where sequence could affect meaning.  Loretta responded:

It is true that there isn't always a single correct total order. If there are 3 articles on a page, they can probably
be read in any order, but I want the information within each article to be ordered correctly.


GL 2.4 Example  6 is meant to describe such the kind of situation the SC is trying to address:

* Example 6: an online newsletter.
The main content area of an online newsletter uses a layout that features two columns of text. [...] There is a "pullquote" in the center of the screen - that
is, a phrase taken from the article and displayed in a larger font to emphasize an important idea. The pullquote is shown over a shaded background and
there is a border around it. Visually, the pullquote overlaps portions of both columns in the text. The page also includes a sidebar with a list of phone
numbers. The visual layout does not require that the content be read in a certain order. However, it is important that people who use screen readers or
text-only displays be able to read the content in a sequence that makes sense. Thus the pullquote and the sidebar should be clearly distinguished from
the text in the left and right columns so that user agents can render the content separately.

[Editorial nit: The word "should" in that last sentence shouldn't be there-- it *should* be changed to *are* for consistency with the  fiction that the example creates.]

To sum up:

1. As Loretta points out, it doesn't really matter whether User X reads the articles in the order in which they appear visually.  

2. But it *does* matter that the user agent is able to distinguish the content of each article from other content in the *perceivable* unit and present that content as a coherent whole. 

3. I think this SC is actually about what happens in the perceivable unit rather than the delivery unit-- each article could well be a separate delivery unit that gets aggregated into what the user sees or hears.

Thinking of it this way might also help with the testability issue Alex raised. And maybe we need to bring in the idea of an "authored unit," too.  Our glossary entry for "authored units" is taken from the Device Independence glossary, and reads as follows:

Some set of material created as a single entity by an author. Examples include a collection of markup, a style sheet, and a media
such as an image or audio clip.

If each article in the newsletter example is an authored unit ("collection of markup"), then maybe the point is that the integrity or structure of the authored unit must remain intact whenever a collection of authored units is assembled into a delivery unit and whenever a delivery unit is transformed into a perceivable unit.

Different aspects of the problem come under the jurisdiction of different guidelines:

As a matter of structural integrity for the authored unit, it comes under GL 1.3.

As a matter of maintaining orientation within the content, it comes under GL 2.4 (... Help users find content, orient themselves within it...).
As a matter of comprehension, it falls under 3.1.

Would the following work as a success criterion under 2.4 L1 SC2 (replacing the one proposed by Yvette/currently at 2.4 L3 SC1)?

The integrity or structure of each authored unit remains intact whenever a collection of authored units is assembled into a delivery unit and whenever a delivery unit is transformed into a perceivable unit.

-- or is this trivial/beside the point? Would there be times when an authored unit did *not* remain intact when aggregated into a delivery unit or when the delivery unit is transformed into a perceivable unit?


"Good design is accessible design." 
John Slatin, Ph.D.
Director, Accessibility Institute
University of Texas at Austin
FAC 248C
1 University Station G9600
Austin, TX 78712
ph 512-495-4288, f 512-495-4524
email jslatin@mail.utexas.edu
web http://www.utexas.edu/research/accessibility/


Received on Thursday, 5 May 2005 16:10:02 UTC

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