Re: definition Re: RE Checkpoint 3.4 again

Hi folks,

The UAWG has spent a lot of time on these definitions (even though
this is more of a content issue). Please check out our definitions 
in the 31 July draft [1]:

Text:

  In this document, the term "text" used by itself refers to a sequence 
  of characters from a markup language's document character set. Refer
  to the "Character Model for the World Wide Web " [CHARMOD] for more 
  information about text and characters. Note: This document makes use
  of other terms that include the word "text" that have highly
specialized 
  meanings: collated text transcript, non-text content, text content, 
  non-text element, text element, text equivalent, and text transcript. 

Then:

  As used in this document a "text element" adds text
  characters to either content or the user interface.
  Both in the Web Content Accessibility Guidelines 1.0 [WCAG10] 
  and in this document, text elements are presumed to produce
  text that can be understood when rendered visually, as 
  synthesized speech, or as Braille. 

Then:

  A text element may consist of both text and non-text data.
  For instance, a text element may contain markup for style
  (e.g., font size or color), structure (e.g., heading levels), 
  and other semantics.

  "Text content" is content that is composed of one or more 
  text elements. 

  A "non-text element" is an element (in content or the user 
  interface) that does not have the qualities of a text
  element. "Non-text content" is composed of one or more 
  non-text elements.

Then:

 Note that the terms "text element" and "non-text element" are 
 defined by the characteristics of their output (e.g., rendering) 
 rather than those of their input (e.g., information sources)
 or their internals (e.g., format). Both text elements and
 non-text elements should be understood as "pre-rendering" 
 content in contrast to the "post-rendering" content that 
 they produce.

There's even more, but the above paragraphs are the key ones.

Why do we go to such lengths?

 - We need the term "text" to mean character sequence for some
   functionalities like text search. Our requirements are limited
   to characters (e.g., no requirement to search for pictures
   of characters in images).

 - The term "non-text element" in WCAG 1.0 checkpoint 1.1
   includes things like ascii art, which is composed of 
   characters. Therefore, we wanted to define "text element" 
   and "non-text element" to be consistent with the intention of
   the checkpoint. It makes sense to say that a text element
   "adds characters" that "can be understood" when rendered.
   Non-text elements do not have this property.


 - Ian

[1] http://www.w3.org/WAI/UA/WD-UAAG10-20010731/glossary#terms


Kynn Bartlett wrote:
> 
> At 8:11 PM -0400 2001/8/01, Charles McCathieNevile wrote:
> >So here is an attempt:
> >
> >non-text (an adjective, as in "non-text element")
> >Something that doesn't rely on writing to communicate its content.
> >Normally, a picture, some sound, a movie, and so on. Note that this usualyl
> >referes to writing as characters output by the computer.
> >A picture of some writing, that is intended to be read, is both a non-text
> >element (in that it does not produce letters or words that the computer
> >renders) so it needs a text equivalent for many users, and a text element in
> >that it relies on written words rather than communicating graphically.
> 
> Please don't allow something to be both "x" and "non-x" at the same
> time.  The logical inconsistency is just too much to simply bury in
> the glossary.
> 
> Here's a straw man definition:
> 
> "Text is any content encoded in Unicode-style letters and/or glyphs.
> Non-text is anything else.
> 
> Someone who is more up on RFCs and the like can fill in a more
> technically precise term for "letters".  If this were 1983 I'd be
> saying "ASCII characters."
> 
> --Kynn
> 
> --
> Kynn Bartlett <kynn@reef.com>
> Technical Developer Liaison
> Reef North America
> Accessibility - W3C - Integrator Network
> Tel +1 949-567-7006
> ________________________________________
> BUSINESS IS DYNAMIC. TAKE CONTROL.
> ________________________________________
> http://www.reef.com

-- 
Ian Jacobs (ij@w3.org)   http://www.w3.org/People/Jacobs
Cell:                    +1 917 450-8783

Received on Thursday, 2 August 2001 10:33:05 UTC