Charles McCathieNevile - 7 august 2002
Extreme Markup 2002
Slides: http://www.w3.org/2002/Talks/0807-xm-xag
What?
Related work
Executive summary
- Ensure that authors can associate multiple media objects as
alternatives
- Create semantically-rich languages
- Design an accessible user interface
- Document and export semantics
1 - alternative media objects
- Equivalent to "equivalent alternatives" in *AG
- Explicit association required
- Unconstrained to type
- allow rich text, video, sign languages, audio, etc.
- Use existing "accessible" techniques (e.g. include SVG)
XAG 1 and Extreme
- 1.1: Provide a mechanism to explicitly associate alternatives for
content or content fragments
- Pass? for images ( by allowing
graphic
in figure
).
- must include a pointer to the thing illustrated by figure
- 1.2: Define flexible associations, where a given kind of relationship
can link to or from objects of varying types without constraint
- Pass?
xref
anywhere,
but what exactly is linked?
- 1.3: Reuse existing accessibility modules to indicate
alternative-equivalent associations
- Fail? Known
issue: Unclear what. Markup or modelling level
- so: Use SVG for images? SMIL test attributes?
XAG 1: other examples
2 - semantically rich languages
- Allow tools to decompose information
- Classify, identify, summarise and structure
- Use existing XML standards
- Seperate style and content, allow for metadata
XAG 2 and Extreme...
- 2.1 Ensure all semantics are captured in markup in a repurposeable
form
- Fail? Text works.... but not
content in
graphic
- 2.2 Separate presentation properties using stylesheet
technology/styling mechanisms
- A clear pass. As one would expect
here ;-)
- 2.3 Use the standard XML linking and pointing mechanisms (XLink and
XPointer)
- Not applicable.
(issue: does Hlink pass?)
- 2.4 Define element types that allow classification and grouping
(header, etc)
- Pass:
front
,
body
, section
, with title
XAG 2 ... continued ...
- 2.5 Provide for a full containment model with chunks of reasonable
size
- Pass.
section
,
subsec1
, and other structure are good.
- 2.6 Define element types that identify important text content
- Pass. abbreviations, references,
etc.
- (Issues: how do you decide what is important? Image
parts?)
- 2.7: Provide a mechanism for identifying summary / abstract / title
- Pass.
Beautiful
- 2.8 Don't overload the semantics of elements
- Pass. (is this about style or
accessibility?)
XAG 2 ...and continued
- 2.9 Reuse accessible modules from schema as originally specified /
intended
- Pass? Nothing "re-used". (See
also 1.3)
- 2.10 Allow association of metadata with distinct elements and groups of
elements
- Fail? (Issue:
you can for metadata that can point...)
- 2.11 Specific checkpoint for Final-form dialects.
- Not Applicable.
(Issue: What really is final form?)
XAG 2: other examples
- VoiceXML - alternative for audio (2.1)
- Using CSS or specifying presentation seperation (2.2)
- SVG: g, title (2.5, 2.7)
- HTML - code, sample, var, kbd, q, blockquote (2.6)
- SVG switch, animate (2.9), metadata (2.10), Xlink (2.3)
- XSL-FO - "where did this come from?" (2.11)
3 - design for accessible UI
(or, Remember there are users)
- Provide default styles and navigation for different media
- Allow for device-independent interaction
- Allow for user control or override of timing
XAG 3 and Extreme
- 3.1 Provide default style sheets for multiple output modalities where
possible
- Pass: XSLT to HTML gives us
various media
- 3.2 Define navigable structures that allow discrete, sequential,
structured, and search navigation functionalities
- Pass: Good structure can be
used
- 3.3 Use CSS or XSLT to describe a basic outline view
- Fail: But this
is 10 minutes CSS or XSLT
- 3.4 Use a device-independent interaction and events model / module
- Not applicable
- 3.5 Allow for user control of interaction timing - rate of change,
external events triggering document changes, etc.
- Not applicable
XAG 3: other examples
- CSS 2 style for HTML 4 (3.1)
- Daisy: navigation structure (3.2)
- A header-based outline for XHTML (3.3)
- SVG: onactivate, onfocus (3.4)
- Spec: User Agents can allow timing override (3.5)
4 - document the semantics
XAG 4 and Extreme
- 4.1 Ensure human-readable documentation conforms to WCAG double A
- Fail - DTD is too complex for
many people. DTD + CSS/XSLT?
- 4.2 Provide a machine-understandable means/mechanism to get from a
document instance to the schema
- Pass: Doctype declaration
- 4.3 Provide explicit human readable definitions for markup
semantics
- Pass - the DTD does say this
- 4.4 Use a schema language that can support explicit human-readable
documentation or annotation of semantics
- Fail. DTD doesn't point to the
semantics on a per-element basis
XAG 4 and Extreme - more
- 4.5 Provide semantic relationships to other schemata where appropriate
and possible
- Pass with XSLT to HTML
- 4.9 Do not assume that element or attribute names provide any
information about element semantics
- Pass. (Issue:
relationship with 4.3?)
- 4.10 Document navigable structures. Describe how discrete, sequential,
structured, and search navigation mechanisms should work
- "Fail". But this is 5 minutes
work.
XAG 4 and Extreme - the rest
Fail all of:
- 4.6 Document accessibility features of the application
- 4.7 Include accessibility requirements in conformance requirements
- 4.8 Document techniques for WCAG, ATAG, and UAAG with respect to the
XML application
XAG 4: other examples
- W3C Specs are getting better at WCAG (4.1)
- Language or Schema mapping (4.5)
- SVG or HTML Accessibility work (4.6, 4.7, 4.8)
Known Issues
- Ordering / grouping / redundancy (this is a draft)
- Relationship to "good style", i18n, etc. guidelines
- How to deal with "final form" languages like XSL-FO
- Applicability to languages like SOAP, RDF
- Reliance on tools providing XML accessibility
- Need review, editing, testing, review
Questions?
Feedback welcome anytime: wai-xtech@w3.org
Latest editor draft: http://www.w3.org/WAI/PF/XML