New Standards and New Initiatives From Open A11y: Draft 1
- New Standards and New Initiatives From Open A11y
First chartered in 2004 as the Linux Foundation Accessibility Workgroup
(LFA), the Open Accessibility (A11y) Group functions today within the Linux
Foundation to establish free and open standards that enable comprehensive
universal access to various computing platforms, applications, and services.
Open A11y exists to make it easier for developers, ISVs, and distributions to support assistive technologies (AT). Assistive technologies enable individuals to make full use of computer-based technology despite variability in physical or sensory abilities due to illness, aging or disability.
Our standards and works in progress can be found on line at: http://a11y.org.
New standards from Open A11y completed and adopted during the past year include:
- 1) AT-SPI For Linux & Unix
- Originally developed for GNOME2, the Assistive Technology Service Provider
Interface (AT-SPI) is the industry consensus, toolkit-neutral interface between
applications and assistive technologies. It enables assistive technology
tools, e.g. screen readers, magnifiers, and even scripting interfaces to query
and interact with graphical user interface (GUI) controls. As such it
facilitates access for individuals who cannot use the standard GUI. It enables developers (or a third party) to build applications that are, or can be made accessible.
- For GNOME2 applications AT-SPI is implemented through libatk. Open A11y is also developing a test suite which will enable developers and distributions to validate end to end accessibility for libatk based applications with a reasonable level of confidence.
- 2) Keyboard Accessibility On Linux & Unix
- Persons unable to use a keyboard and mouse sometimes use alternative
devices. However, many users can be accommodated programatically through
software that causes a standard keyboard to behave differently. Among the most mature of accessibility accommodations commonly available on computing platforms, many of these features and behaviors have long been available in the XKB specification, available at:
- Open A11y has standardized on a subset of the XKB specification in order to provide standard keyboard features and behaviors required by persons with mobility impairments in Linux and Unix distributions through two standards specification documents:
- Individuals with mobility impairments will benefit by having such features
built-in and available through standard activation strategies, such as tapping
the Shift key five times to activate Sticky Keys. The routines provided by the
API will also benefit assistive technologies such as on screen keyboard and
screen reader applications.
- 3) IAccessible2 For Microsoft Windows
- IAccessible2 complements and extends, the capabilities of Microsoft's MSAA
(Microsoft Active Accessibility) API to address gaps on Windows computers that
have been addressed by later generation accessibility APIs. IAccessible2 was
modeled after the OpenOffice accessibility API called the UNO Accessibility
API aka UAAPI. The OpenOffice UAAPI and GNOME ATK/AT-SPI are, in turn, both
modeled on the Java Accessibility API which IBM and Sun jointly defined.
- There was a pointed effort within IBM to harmonize the IAccessible2 API with
the ATK/AT-SPI API. This harmonization is proving to be very helpful as
advanced accessibility features are added to Firefox 3 which will provide
accessibility on both the Linux and Windows platforms. This newest Open A11y accessibility standard will further help developers create cross-platform applications by reducing the need for platform specific customization.
- New and continuing initiatives at Open A11y include:
- A) Expert Handlers
- Generalized content markup (such as HTML) is complimented by markup specifications that facilitate more semantically precise content markup.
Examples include MathML and MusicXML. Assistive technology (AT) typically
handles generalized content markup, but does not know about specialized
markup. Because of this, users of AT are unable to access or navigate specialized markup effectively.
- The Open A11y Expert Handlers group is exploring a standardized plug-in mechanism for AT software to allow the expert software to provide enhanced, semantically rich access to specialized markup