RE: SC 1.3.5: meaning-critical sequences

I think that we need 2 properties to be true, and I'm still wrestling
with how to express them.

 

1. We need to be able to programmatically determine when it is safe to
change the order of parts of the content, so that alternate
presentations don't change the meaning.

 

This is what will need technology-specific techniques. 

 

2. When the sequence of the content affects the meaning, the sequence of
<what?> must be meaningful in the first place.

 

I haven't been able to figure out how to phrase the second condition.
This is what says that the words in a paragraph must be in a meaningful
order. This is what breaks down, for instance, when we try to represent
two column text in a simple text document. Is this the source order of
the content? What if the technology uses a different order in its source
from the order used in rendering? Is it the default render order that
needs to have this property?

Loretta Guarino Reid 
lguarino@adobe.com 
Adobe Systems, Acrobat Engineering 

________________________________

From: John M Slatin [mailto:john_slatin@austin.utexas.edu] 
Sent: Tuesday, January 24, 2006 1:19 PM
To: Loretta Guarino Reid; public-wcag-teamb@w3.org
Subject: RE: SC 1.3.5: meaning-critical sequences

 

Loretta, thanks for walking through this SC so carefully. I think the
analysis makes sense.

 

Based on what you've said, I think we need a general technique plus a
list of techniques that can be used to make reading order
programmatically determined. As you've noted, there are different
techniques for different kinds of content (e.g., ordered lists, etc.).

 

YOu've also pointed out that some people find the phrase
"meaning-critical sequence" hard to understand. So here's a title for
the general technique:

 

<proposedTitle>

Defining a programmatically determined reading order when content must
be presented in a specific sequence

</proposedTitle>

 

In How to Meet SC 1.3.5, this might look like the following:

Defining a programmatically determined reading order when content must
be presented in a specific sequence

 

AND

 

one or more of the technology-specific techniques listed below.

 

HTML Techniques

Using the ol element to present list items in a specific sequence

Etc.

 

Thoughts?

 

John


"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/
<http://www.utexas.edu/research/accessibility/> 

 

 

	 

	
________________________________


	From: public-wcag-teamb-request@w3.org
[mailto:public-wcag-teamb-request@w3.org] On Behalf Of Loretta Guarino
Reid
	Sent: Thursday, January 19, 2006 2:48 pm
	To: public-wcag-teamb@w3.org
	Subject: SC 1.3.5: meaning-critical sequences

	The concept that this phrase is trying to communicate is that
there is some content for which the order of the content is critical to
correctly understanding its meaning. For other content, it is not
critical. This is true at different levels of granularity, so that the
order within some portion of the content is critical, but the larger
units of content can be reordered without affecting meaning.

	For example, you should be able to change the order of items in
an unordered list without affecting its meaning. But not of an ordered
list. So an ordered list marks a meaning-critical sequence, but an
unordered list does not. 

	Text in a container (paragraph, list item, table cell, etc) is
always a meaning-critical sequence. Tables are meaning-critical
sequences. The paragraphs in an article are a meaning-critical sequence.
The ordering of a navigation bar and a search tool, however, is not
meaning-critical.

	If contents contain images, is there location meaning critical?
There are usually (but not always) a number of different places the
image could occur in the content without affecting the meaning.

	For those of you who are more knowledgeable about html and css,
how do you know when it is safe to relocate an element in css, and when
it is not?

	(In describing this, I realize that "meaning-critical sequences"
is not a good phrase to be using. It makes it sounds as if some
sequences or sections of content are critical to meaning, and other
sequences or sections of content are not.)

	In order to understand the content, especially when preparing
alternate presentations, 

	1.      We need to be able to programmatically determine when
the alternate presentation can safely change the order of the content.
(I believe the default for most content in most technologies is that the
order cannot be changed.)

	2.      Where the programmatically determined order of the
content can't be changed, we need it to be a meaningful order.

	The second requirement can really only be checked manually, much
like checking whether an alternate description is equivalent to its
image.

	Does this explanation make sense? Does anyone have ideas of
alternate wordings for the techniques and/or success criterion that
would make it less confusing?

	Loretta Guarino Reid

	lguarino@adobe.com

	Adobe Systems, Acrobat Engineering