- From: Wendy Chisholm <wendy@w3.org>
- Date: Tue, 26 Apr 2005 22:35:27 -0400
- To: wai-gl <w3c-wai-gl@w3.org>
- Message-ID: <426EFA6F.5000705@w3.org>
Attached is an html file with the issue summary for Guideline 1.1 as
well as proposed text for the guideline and related definitions.
The proposal for the first criterion is really rough. Ideas welcome.
"@@s" indicate questions. Comments related to issues and changes
enclosed in {}
Best,
--wendy
===
Summary of issues
* Issue 1486, issue 1487, issue 1488 - rewording proposals from the
report on the impact of not setting a baseline.
* Issue 1368 - GL 1.1, SC L1 - division of content isn't clear -
propose that we handle this in the Guide. If that's not acceptable,
perhaps add a paragraph to Guideline 1.1 that explains the differences
between the criterion.
* Issue 1369 - Commentor feels that example 4 was inadequate. See
proposed wording below.
* Issue 1433 - Commentor feels that context should determine the
appropriate text alternatives for non-text content. Specifically cited
example 4. Fixed example 4, but the issue is not addressed. perhaps this
will be clarified in the guide?
* Issue 1434 - Broken link. Overcome by events.
* Issue 1075 - Text alternatives that are not explicitly associates
are sometimes okay. I added a long note to this criterion. Not sure if
it solves the issue.
* Issue 791 - Clarification needed about the benefit of text
alternatives for people who have difficulty reading text. Created a
separate benefit to explain.
* Issue 1439 - Guideline 1.1, Level 1, point 6 is needed. Deleted
the editorial note that noted the similarities between criterion.
* Issue 895 - To grossly oversimplify the issue, "is a noscript
required for every script." Include scripted content in proposed
definition of non-text content, text, and functional and slightly
modified what is required for functional non-text content.
* Issue 587 - Definitions needed for text alternative, text,
unicode, non-text content, and ASCII art. Should also close issue 673.
Proposal for Guideline 1.1 Provide text alternatives for all non-text
content.
Level 1 Success Criteria for Guideline 1.1
1. For all non-text content that is functional text alternatives
identify the non-text content in such a way that the label serves the
same purpose as the non-text content. If the non-text content is a
collection of functional non-text content, each function and collection
of functions within is identified. [I] {Issue 1486 - Deleted the phrase:
", such as graphical links or buttons" tried rewording to include web
apps and widgets within web apps. This is probably not technically
correct and could use a plain language rewrite.}
How to provide text alternatives for content that is functional.
(Informative)
2. For all non-text content that is used to convey information, text
alternatives convey the same information. [I]
Note: for multimedia, this means that two alternatives are
provided:
1. a transcript
2. a text alternative that identifies the purpose or function
of the multimedia
How to provide text alternatives for content that conveys
information. (Informative)
3. 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. [I]
How to provide text alternatives for content that creates a
specific sensory experience. (Informative)
4. Non-text content that does not convey information, functionality,
or create a specific sensory experience is implemented such that it can
be ignored by assistive technology. [I] {Editorial: replaced "provide
information" with "convey information" and added "create a specific" to
"sensory experience" for consistency. Issue 1487 - replaced "marked"
with "implemented.}
How to provide text alternatives that can be ignored by assistive
technology. (Informative)
5. Any text alternatives are explicitly associated with the non-text
content. [I]
Note: At a minimum, a text alternative that serves the same
purpose as the non-text content must be explicitly associated with the
non-text content (per the first success criterion). However, if an
additional text alternative is needed to understand the non-text
content, it must be easy to find either because:
* the additional text alternative appears immediately before
or immediately after the non-text content [in reading order? in object
model?] or
* the additional text alternative is referred to in the
explicitly associated text alternative or
* the additional text alternative is itself explicitly
associated. {Issue 1075 - Added the note in an attempt to clarify how
and when text alternatives may not be explicitly associated with
non-text content.}
How to explicitly associate text alternatives with non-text
content. (Informative)
6. For live audio-only or live video-only content, such as internet
radio or Web cameras, text alternatives describe the purpose of the
presentation or a link is provided to alternative real-time content,
such as traffic reports for a traffic Web camera
Note: real-time content does not imply real-time captions. {Issue
1439 - deleted editorial note, "Editorial Note: This is similar to #1
above, yet it seems we need to specifically address audio-only and
video-only content to avoid confusion.}
Level 2 Success Criteria for Guideline 1.1
1. No level 2 success criteria for this guideline.
Level 3 Success Criteria for Guideline 1.1
1. For multimedia content, a combined transcript of audio
descriptions of video and captions is available. [I] {Issue 1488 -
replaced "provided" with "available."}
How to provide descriptions of all important visual information
for multimedia. (Informative)
Who Benefits from Guideline 1.1 (Informative)
* People who are blind, have low vision, or have cognitive
disabilities can have text alternatives read aloud to them by assistive
technology.
* People who have trouble reading text may use tools that both read
text aloud and highlight the words as they are read. In some cases, it
may be difficult for someone to recognize visual information and the
text alternative may help him or her understand the purpose of the
non-text content. {Issue 791 - separated the 1st benefit into 2 to
clarify how text alternatives may benefit people who have difficulty
reading text.}
* People who are deaf, are hard of hearing, or who are having
trouble understanding audio information for any reason can read the text
presentation or have it translated and presented as sign language by
assistive technology.
* People who are deaf-blind can read the text in braille.
* Additionally, text alternatives support the ability to search for
non-text content and to repurpose content in a variety of ways.
Examples of Guideline 1.1 (Informative)
* Example 1: an image used as a button.
A magnifying glass icon is used to link to the search page of a
Web site. A screen reader identifies the button as a link and speaks the
text alternative, "Search."
* Example 2: a data chart.
A bar chart compares how many widgets were sold in June, July, and
August. The short label says, "Figure one - Sales in June, July and
August." The longer description identifies the type of chart, provides a
high-level summary of the data comparable to that available from the
chart, and provides the data in a table.
* Example 3: an audio recording of a speech (no video).
The link to an audio clip says, "Chairman's speech to the
assembly." A link to a text transcript is provided immediately after the
link to the audio clip.
* Example 4: a recording of a symphony.
The Mars Philharmonic Orchestra's "Upcoming performances" page has
a link to a 3 minute clip of the orchestra's rendition of Beethoven's
5th Symphony. The purpose is to encourage readers to buy tickets to a
live performance. The link to the audio clip says, "Beethoven's 5th
Symphony performed by the Mars Philharmonic Orchestra." On the same page
is information about Beethoven and the 5th Symphony. Elsewhere on the
Mars Philharmonic Orchestra's Web site is an educational area. There is
a link to the same 3 minute clip of the orchestra performing Beethoven's
5th Symphony. The link is the same, "Beethoven's 5th Symphony performed
by the Mars Philharmonic Orchestra." However, the page describes how
this clip relates to the drama that Beethoven creates in his 5th
symphony and describes a specific rhythm captured in this clip. It goes
on to explain how this symphony "crystallized Beethoven's mature
compositional innovations." (from Symphonies of Beethoven) {Issue 1369 -
to clarify that in different situations a description may be provided
and may be very different. Previously, there was no description, only an
audio clip.}
* Example 5: an animation that illustrates how a car engine works.
An animation shows how a car engine works. There is no audio and
the animation is part of a tutorial that describes how an engine works.
All that is needed is a description of the image. From "How car engines
work: Internal combustion"
* Example 6: a pair of images used to create a visual effect.
Two images are used to create curved edges on a "tab" interface.
The images do not provide information, functionality, or a sensory
experience and are marked such that they can be ignored by an assistive
technology.
* Example 7: an internet radio station.
A radio station broadcasts over the internet. The station's Web
site describes the type of music played, a schedule of the shows, and
the "current song" is updated each time the DJ starts a new track.
Interviews are recorded and published in the archives. Transcripts of
the archived interviews are provided per Guideline 1.2 Provide
synchronized alternatives for multimedia.
Editorial Note: Does the above example help to clarify level 1
success criterion 6 or does it need additional clarification?
* Example 8: a traffic Web camera.
A Web site allows end-users to select from a variety of Web
cameras positioned throughout a major city. After a camera is selected,
the image updates every 2 minutes. A short text alternative identifies
the Web camera as, "TraffiCam." The site also provides a table of travel
times for each of the routes covered by the Web cameras. The table is
also updated every 2 minutes.
Proposals for definitions
Related to issue 587 (defn of text equiv/alternative) and issue 895
(when to provide text alternatives for application-like non-text
content, e.g., defn of non-text content)
ASCII art
Proposed definition: An arrangement of characters intended to
convey information. See non-text content. {Propose new definition to
clarify that ASCII art is not text and is intended to "convey
information"}
Current definition: Graphic representations that are created by
a spatial arrangement of text characters. Although it can be
rendered on a text display, it is not text.
content
Proposed definition: Information that forms Web sites and Web
applications: the code and markup that define the structure,
presentation, and interaction, as well as text, images, and sounds
that convey information to the end-user. In this specification, the
noun "content" is used in three ways:
1. It is used to mean the delivery unit as a whole or in
parts - the information that the author provides such that the user
agent can generate an accessible perceivable unit(s).
2. It is used to mean the perceivable unit(s) as a whole or
in parts.
3. It is used in the term non-text content.
Current definition: none.
delivery unit
Proposed definition: The information that the user agent
receives and renders into a perceivable unit. {Editorial: Thought we
might need a plain language version. Propose that if we use a plain
language version, also include the more technically correct
definition from the DI Glossary}
Current definition: A set of material transfered between two
cooperating web programs as the response to a single HTTP request.
The transfer might, for example, be between an origin server and a
user agent. [From Device Independence Glossary]
explicitly associated
Proposed definition: Implemented in such a way that
relationships can be programmatically determined. {Issue 1075 - new
definition proposed to help clarify criterion}
Current definition: none.
functionality
Proposed definition: Performing or able to perform an action in
response to user input.
Current definition: Functionality is the purpose or intended
effect of the content. This may include presentation of information
, data collection, securing a response from the user, providing user
experience, linking to other content, testing, confirmation,
purchasing, etc.
non-text content
Proposed definition: Content that is not represented by a
Unicode character or sequence of Unicode characters
* functional non-text content - content that is capable of
performing an action in response to user input and is not text.
* non-text content used to convey information - content that
communicates an idea or data and is not text.
* non-text content that is intended to create a specific
sensory experience - arrangements of sounds, colors, forms,
movements, or other elements in a manner that cause a reaction in
the viewer or listener.
Current definition:
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.
perceivable unit
Proposed definition: The result of a user agent rendering the
contents of a delivery unit. User agents may or may not render all
information in a delivery unit. In some cases, a single delivery
unit may be rendered as multiple perceivable units. For example, a
single html file that is rendered as a set of presentation slides.
Most perceivable units contain presentation and the means for
interaction. However, for some devices such as printers, a
perceivable unit may only contain presentation. {An attempt at a
plain language definition. Similar concern as to delivery unit.}
Current definition: A set of material which, when rendered by a
user agent, may be perceived by a user and with which interaction
may be possible.
User agents may choose to render some or all of the material
they receive in a delivery unit as a single perceivable unit or as
multiple perceivable units.
Most perceivable units provide both presentation and the means
for interaction. However, on some types of device, such as printers,
perceivable units might contain only presentation. [From the Device
Independence Glossary]
text
Proposed definition: A sequence of characters. Characters are
those included in the Unicode / ISO/IEC 106464 repertoire. Refer to
Characters (in Extensible Markup Language (XML) 1.1) for more
information about the accepted character range.
[@@what about functional text content? e.g., links?] [@@refer to
XML 1.0 or 1.1 - Christophe felt 1.0 is safer, but yet it's dated
and not as "internationalized" - ala Richard's talk at the Technical
Plenary]
Current definition: none
text alternative
Proposed definition: Text that is used in place of or in
addition to non-text content. {Issue 587 - new definition for text
alternative}
Current definition:
* 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.
unicode
Proposed definition: Unicode is a universal character set that
defines all the characters needed for writing the majority of living
languages in use on computers. For more information refer to the
Unicode Consortium or to Tutorial: Character sets & encodings in
XHTML, HTML and CSS produced by the W3C Internationalization
Activity. [Additional optional clarification: This does not mean
that all documents should be encoded in Unicode. It means that
documents should only contain characters defined by Unicode. Any
encoding may be used for your document as long as it is properly
declared and is a subset of the Unicode repertoire. ]
Current definition: none.
--
wendy a chisholm
world wide web consortium
web accessibility initiative
http://www.w3.org/WAI/
/--
Attachments
- text/html attachment: text-equiv-proposal.html
Received on Wednesday, 27 April 2005 02:35:53 UTC