WCAG 2.0 references to and definitions of Unicode and text
Notes for writing a proposal for Issue 673
- We are working with Internationalization (I18N) on including references and
improved wording related to the WCAG 2.0 definitions for "text" and
"character encoding".
Proposals
- text - A sequence of characters included in the Unicode character set.
Refer to Characters in
Extensible Markup Language (XML) 1.0 (Third Edition) for more specific
information about the accepted character range.
- Unicode - In this document, we use "Unicode" to refer to the Unicode
character set and not the character encoding (the Unicode character set
may be encoded in ASCII, UTF-8, UTF-16, etc. characters in the Unicode
set can be created with numeric character references - so there is a
clear separation between the character encoding and those characters
defined in the Unicode character set that we consider "text"- @@provide
reference to I18N list?)
- non-text content - Non-text content is content that can not be
represented by a Unicode character or sequence of Unicode characters.
Non-text content includes but is not limited to
- images and graphics,
- sound clips, movies, and animations,
- ASCII art (which may use several unicode characters to create an
image)
Providing text alternatives for non-text content is addressed in
Guideline 1.2, providing captions and audio descriptions of multimedia is
addressed in guideline 1.2, and interacting with non-text content via
scripts, applets, and programmatic objects is addressed in guideline 4.2
.
How is "text" used in the 30 July 2004 WCAG 2.0 Working Draft?
- Guideline 1.1 - text alternative, non-text content, text document,
reading text, text presentation, text in braille, text equivalent, text
transcript
- Guideline 1.2 - text transcript, ongoing text report, equivalent
presentation (audio, visual, or text), text descriptions, text label and
description
- Guideline 1.3 - text coding, braille (text), mentions in text,
available in text
- Guideline 1.4 - text presented over a background, the text to be
distinguished, Text that meets guideline 1.1 should satisfy this
criterion, the resource provides a mechanism to allow the text, text is
easily readable, separate text from background images, A background image
and text are arranged
- Guideline 2.2 - written text, blinking or scrolling text, contains
minimal text
- Guideline 2.4 - visual vs. text orientation, part of the running
text
- Guideline 2.5 - provided to the user in text, to enter text directly,
when text entry is required, writing text in forms, text input
- Guideline 3.1 - foreign words in text, link text, text-only, can voice
text, the language of the text of the site, described in the text
- Guideline 4.1 - non-visual or text-only users
- Guideline 4.2 - renders visual text
- Glossary
- ASCII art - spatial arrangement of text characters, text
display
- captions - captions are text equivalents
- controlled languages - The purpose is to make texts easier to
- keyboard interface - the purpose of generating text or an internal
method for generating text
- non-text content: non-text content includes but is not limited to
images, text in raster images, image map regions, animations (e.g.,
animated GIFs), ASCII art , images used as list bullets, spacers,
graphical buttons, sounds (played with or without user interaction),
stand-alone audio files, audio tracks of video, and video. It also
includes any text that can not be translated into Unicode.
Note: Scripts, applets, and programmatic objects are not covered
in this definition and are addressed in guideline 4.2 .
- text - Editorial Note : We are currently working with
Internationalization (I18N) on including references and improved
wording related to the WCAG 2.0 definitions for "text" and "character
encoding".
- text description: Editorial Note : We need to include a definition
of text description here.
- text label: Editorial Note : We need to include a definition of
text label here.
- text-alternative: A text alternative
- serves the same function as the non-text content was intended
to serve.
- communicates the same information as the non-text content was
intended to convey.
- may contain structured content or metadata.
Note: Text-alternatives should be easily convertible to braille or
speech, displayed in a larger font or different colors, fed to
language translators or abstracting software, etc.
Uses of non-text content
- Guideline 1.1 Provide text alternatives for all non-text content.
- Text-alternatives are explicitly associated with non-text content
and one of the following is true:
- For non-text content that is functional, such as graphical
links or buttons, text alternatives identify the purpose or
function of the non-text content; or,
- For non-text content that is used to convey information, text
alternatives convey the same information; or,
- For non-text content that is intended to create a specific
sensory experience, such as music or visual art, text
alternatives identify and describe the non-text content; or,
- Multimedia alternatives are provided according to guideline 1.2
; or,
- Non-text content that does not provide information or
functionality is marked such that it can be ignored by assistive
technology
- Guideline 3.1
- Adding non-text content to the site for key pages or sections
specifically to make the site more understandable by users who cannot
understand the text only version of the site.
- Including non-text content to supplement text for key pages or
sections of the site.
- Glossary
- non-text content: non-text content includes but is not limited to
images, text in raster images, image map regions, animations (e.g.,
animated GIFs), ASCII art , images used as list bullets, spacers,
graphical buttons, sounds (played with or without user interaction),
stand-alone audio files, audio tracks of video, and video. It also
includes any text that can not be translated into Unicode.
Note: Scripts, applets, and programmatic objects are not covered
in this definition and are addressed in guideline 4.2 .
- text-alternative: A text alternative
- serves the same function as the non-text content was intended
to serve.
- communicates the same information as the non-text content was
intended to convey.
- may contain structured content or metadata.
Note: Text-alternatives should be easily convertible to braille or
speech, displayed in a larger font or different colors, fed to
language translators or abstracting software, etc.
Notes from previous discussions
From Martin
Characters are the result of some input operation (which could be typing
on a keyboard, using a mouse to select a character in a point-and-click
fashion from a pannel, using voice input,...). I think what you want to say
is that operations (which includes character input, but also other things
such as navigation) can be achieved with means other than pointing
devices.
As an example, pressing the TAB key inserts a TAB control character
(	 in XML notation) into the text in the context e.g. of text input
in a plain text editor. It definitely causes other actions (e.g. jumping to
the next link or form in a browser,...) in other contexts. In these cases,
this has nothing to do with the TAB character, only with the TAB key on the
keyboard. Some other keys on a keyboard don't have a corresponding
character at all, and some have a character in Unicode solely for the
purpose of printing that symbol in manuals.
From Richard
My guess is that the intent was to say something along the lines of
"represented in the Unicode *character set*". Unicode/ISO 10646 is the
document character set for HTML 4.0 and XML, meaning that although any
encoding can be used, characters used must be found in Unicode to fit the
reference processing model. (See
http://www.w3.org/International/questions/qa-doc-charset.html )
From Gregg with Richard and Martin at lunch on 2 March)
Inside of PDF they may use a different code -- or some docs may be in
compressed form that is decompressed in player -- but not change into
Unicode until a 'copy' or export operation is done on the text.
Other references
$Date: 2004/09/08 23:48:49 $ Wendy Chisholm