- From: Ian B. Jacobs <ij@w3.org>
- Date: Fri, 10 May 2002 12:06:34 -0400
- To: w3c-wai-ua@w3.org
- CC: robla@real.com
Dear UAWG,
I received an action item at the 4 April 2002 teleconference [1]
to propose some text for the chapter on conformance about
"conformance profiles" for other specifications (issue 520 [2]).
- Ian
[1]
http://lists.w3.org/Archives/Public/w3c-wai-ua/2002AprJun/0027
[2] http://www.w3.org/WAI/UA/issues/issues-linear-cr2#520
<PROPOSAL>
3.11 Including UAAG 1.0 requirements in other specifications
Authors of technical specifications (such as W3C Recommendations)
should incorporate the requirements of UAAG 1.0 as part of
conformance to their specifications. This may be done by direct
inclusion, or by reference using a conformance profile. Direct
inclusion promotes the integration of accessibility requirements;
inclusion by reference is easier to do.
3.11.1 General tips
1) Identify accessibility features of the specification where
they are defined (see checkpoint 8.1). Optionally, create an
appendix of these accessibility features as well.
2) Remember to include user interface requirements as part of
conformance to the specification. Authors of technical
specifications tend to focus more on rendering or other
content-related behavior and less on user interface
requirements. UAAG 1.0 makes a number of user interface
requirements that authors will need to consider (such as those
in Guideline 5 pertaining to viewport behavior).
3) Include a general reference to UAAG 1.0 and Techniques for
UAAG 1.0 (see the section "How to refer to UAAG 1.0").
For more information on designing specifications that promote
accessibility, refer to WAI's "XML Accessibility Guidelines"
[XAG10].
3.11.2 Direct inclusion of requirements
1) Rather than include the generic UAAG 1.0 requirements, tailor
them to the specification. Be specific in the requirement, and
include (in context) a reference to the original UAAG 1.0
checkpoint. The following examples illustrate what is
meant by direct inclusion:
- In an HTML specification, where the SCRIPT, APPLET, and
OBJECT elements are defined, include a statement such as "Per
checkpoint 3.4 of UAAG 1.0, a conforming user agent must allow
configuration not to execute scripts, applets, or other
executable content."
- In a CSS specification, where the 'text-decoration' property
is defined, include a statement such as "A conforming user
agent must either:
a) allow configuration to override the 'blink' value
with the 'none' value, or
b) ignore the 'blink' value.
This is required by checkpoint 3.3 of UAAG 1.0 [UAAG10]."
Note how these examples refer to the specific elements,
attributes, properties, etc. of the specifications.
2) Including some UAAG 1.0 requirements in a specification is
better than including no requirements. However, since UAAG 1.0
requirements are designed to complement one another, arbitrary
selection of requirements may result in accessibility gaps.
Authors are encouraged to select requirements in groups defined
by the conditional content mechanisms of content, selection,
and input modality labels.
3.11.3 Conformance profiles
Section G.5 of the SVG 1.0 Recommendation states:
"Additionally, an authoring tool which is a Conforming SVG
Generator conforms to all of the Priority 1 accessibility
guidelines from the document "Authoring Tool Accessibility
Guidelines 1.0" [ATAG] that are relevant to generators of SVG
content."
This statement requires conformance to the Authoring Tool
Accessibility Guidelines as part of conformance to SVG 1.0 (for
certain classes of tools). This type of "conformance requirement
by reference" is also possible for UAAG 1.0. However, since
conditional conformance (section 3.2) to UAAG 1.0 can vary beyond
three conformance levels, it is important for references to state
precisely what is required. This is called a conformance profile.
This section explains how to create a valid conformance profile
to UAAG 1.0. UAAG 1.0 does not define any (named) conformance
profiles, just the mechanism for creating them.
A valid conformance profile must include the following
information:
1) The guidelines title/version
2) The conformance level required: "A", "Double-A", or
"Triple-A".
3) Content type labels: The profile must include at
least one content type label (whose requirements
must be satisfied).
4) Selection label: The profile must indicate whether
a conforming user agent is required to implement
a selection mechanism.
A valid conformance profile should include the following
information:
1) Applicability: Which checkpoints (or portions of checkpoints)
do not apply for this specification. For instance, if a
specification does not define "tables", the conformance profile
should indicate that checkpoint 10.1 does not
apply. Specification authors should include rationale in their
profiles that explains why a checkpoint does not apply.
A valid conformance profile may include the following
information:
1) Input modality labels: If conformance for pointer or voice
input is required in addition to keyboard input.
Note that the following are always required and therefore need
not appear in a conformance profile:
1) Keyboard input requirements
2) Content focus requirements (only when the content includes
enabled elements; see checkpoint 9.1).
The following is an example of a valid conformance profile:
<EXAMPLE>
"As part of conformance to MyFormat 1.0, a user agent must
satisfy the following conformance profile of the
"User Agent Accessibility Guidelines 1.0" [UAAG10]:
a) Conformance Level A
b) Content type labels: VisualText, ColorText, Image,
Animation, and Video. This means that a conforming
MyFormat user agent must satisfy the requirements
associated with those labels; refer to UAAG 1.0
section 3.5 for details.
c) Selection: A conforming MyFormat user agent must
implement a text selection mechanism, and therefore
satisfy the requirements associated with the UAAG 1.0
selection label; refer to UAAG 1.0 section 3.7
for details. A conforming MyFormat user agent is
only required to allow users to select text content.
d) Applicability: The following UAAG 1.0 checkpoints
do not apply to MyFormat and therefore do not need
to be satisfied for conformance to this specification:
- 1.2, 3.4, 9.5, 9.6: MyFormat does not allow inclusion
of scripts. Thus, there are
no author-supplied event handlers.
- 2.4, 2.6: MyFormat does not involve synchronization.
- 2.5, 4.6: MyFormat does not define captions.
- 10.1: MyFormat does not define tables.
[And so on]
</EXAMPLE>
Then, in the references section, include the URI of the UAAG
1.0 specification.
</PROPOSAL>
Notes on the proposal:
- I don't think it's necessary to say anything special about
mixing formats (e.g., XHTML + MathML + SVG), but I haven't
thought about it much.
--
Ian Jacobs (ij@w3.org) http://www.w3.org/People/Jacobs
Tel: +1 718 260-9447
Received on Friday, 10 May 2002 12:40:05 UTC