Assistive Technology Service Provider Interface: Difference between revisions

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{{Short description|Computer accessibility framework}}

'''Assistive Technology Service Provider Interface''' ('''AT-SPI''') is a [[toolkit]]-neutral way of providing [[accessibility]] facilities in [[application software|applications]]. It was developed by the [[GNOME]] project. AT-SPI toolkits provide a logical representation of the content of the application. Helpful assistants like [[screen reader]]s or [[screen magnifier|magnifier]]s can then allow disabled persons to browse and interact with the applications.

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| title = AT-SPI

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| license = [[GNU LGPL]] (version 2)<ref name=license>{{cite web | url = https://git.gnome.org/browse/at-spi2-core/tree/COPYING | title = AT-SPI git source code repository, COPYING file | accessdate = 2014-04-10 }}</ref>

| website = {{URL|https://wiki.gnome.org/Accessibility}}

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'''Assistive Technology Service Provider Interface''' ('''AT-SPI''') is a platform-neutral framework for providing bi-directional communication between [[assistive technologies]] (AT) and applications.<ref>{{cite web| url = http://www.linuxfoundation.org/collaborate/workgroups/accessibility/atk/at-spi/overview| title = ATK/AT-SPI SIG Overview| accessdate = 2014-04-10| archive-date = 2014-04-13| archive-url = https://web.archive.org/web/20140413132602/http://www.linuxfoundation.org/collaborate/workgroups/accessibility/atk/at-spi/overview| url-status = dead}}</ref> It is the ''de facto'' standard for providing accessibility to free and open desktops, like [[Linux]] or [[OpenBSD]], led by the [[GNOME project|GNOME Project]].

AT-SPI can also be used for automated testing of user interfaces, with tools such as [[Linux Desktop Testing Project]] and [[Dogtail]].

One common nomenclature to explain an accessibility framework is a usual client-server architecture. In that way, [[Assistive technology#Computer accessibility|Assistive Technologies]] (ATs), such as [[screen readers]], would be the clients of that framework, and computer applications would be the server. In this architecture, client and server need to communicate with each other, usually using the [[Inter-process communication|IPC]] technology of the platform. Ideally the accessibility framework exposes this to the client and server in a transparent way.

It is currently supported by [[GTK+]] 2, [[Java (programming language)|Java]]/[[Swing (Java)|Swing]], the [[Mozilla]] suite, [[StarOffice]]/[[OpenOffice.org]] and [[Qt (framework)|Qt 4]]<ref>[http://doc.qt.nokia.com/4.0/qt4-accessibility.html Cross-Platform Accessibility Support in Qt 4], by [[Trolltech]]</ref> (the framework used by [[KDE]]).

Usually the API for both client-side and server-side applications are the same, and the accessibility framework provides a client-side and a server-side implementation of that API. In the case of GNOME, there are two different APIs, one for the client-side (AT-SPI) and a different one for the server-side ([[Accessibility Toolkit]] (ATK)) due to historical reasons related to the underlying technologies.<ref name=webkitgtk>{{cite web|last=Sánchez Prada|first=Mario|title=Accessibility in [WebKit]GTK+|url=http://mariospr.org/2013/02/03/accessibility-in-webkitgtk/|date=February 3, 2013|accessdate=2014-04-10}}</ref>

The [[Free Standards Group]] is considering AT-SPI for adoption as a standard.<ref>Free Standards Group, [http://accessibility.freestandards.org/a11yweb/forms/soi.php Statement On Desktop Accessibility Development] (2005-09-25). Accessed 2007-02-06.</ref>

==Implementations==

== External links ==

* [http://directory.fsf.org/project/at-spi/ at-spi], at the [[Free Software Directory]]

AT-SPI was originally designed for using [[Common Object Request Broker Architecture]], an object-based [[Inter-process communication|IPC]]/[[Remote procedure call|RPC]] technology, for its transport protocol. The AT-SPI specification itself was tied to CORBA as it was defined in CORBA [[Interface description language|IDL]]. AT-SPI used the GNOME project's own fast and lightweight CORBA implementation, ORBit, and its own framework for creating CORBA components, [[Bonobo (component model)|Bonobo]].<ref>{{cite web|title=Orca Documentation Series|url=https://www.mit.edu/~rjc/orca-docs.html|accessdate=2014-04-10|archive-date=2014-04-13|archive-url=https://web.archive.org/web/20140413132918/http://www.mit.edu/~rjc/orca-docs.html|url-status=dead}}</ref>

* [http://projects.gnome.org/accessibility/ GNOME Accessibility Project homepage]

The GNOME project decided that the 3.0 release would be free of ORBit and Bonobo, meaning that a [[D-Bus]] AT-SPI solution was required.<ref>{{cite web|title=Planning for GNOME 3.0|url=https://wiki.gnome.org/ThreePointZero/Plan|accessdate=2014-04-10}}</ref><ref>{{cite web|title=GNOME 3 Porting Guide|url=https://wiki.gnome.org/DevGnomeOrg/Gnome3PortingGuide|accessdate=2014-04-10}}</ref> In an effort to move AT-SPI forward, a D-Bus project was started in November 2006. This took the form of a performance and design review available on the GNOME wiki. Work began on the implementation in May 2007.<ref>{{cite web|title=Accessibility/ATK/AT-SPI/AT-SPI on D-Bus|url=https://wiki.linuxfoundation.org/en/AT-SPI_on_D-Bus#Background|accessdate=2014-04-10}}</ref> The D-Bus version of AT-SPI, AT-SPI version 2, was released along with GNOME 3.0 in April 2011.<ref>{{cite web|title=GNOME 3.0 released: better for users, developers|url=http://www.gnome.org/press/2011/04/gnome-3-0-released-better-for-users-developers-3/|accessdate=2014-04-10}}</ref><ref>{{cite web|title=Git source code released with GNOME 3.0|url=https://git.gnome.org/browse/at-spi2-atk/log/?h=gnome-3-0|accessdate=2014-04-10}}</ref>

==Support==

AT-SPI provides an ATK bridge, so all the widget systems or applications that implement ATK will automatically communicate all their events to AT-SPI. The GNOME widget system, [[GTK+]], or [[Mozilla]] applications like [[Firefox]] and [[Mozilla Thunderbird|Thunderbird]] for Linux implement ATK, so they communicate out-of-box with AT-SPI. However, it is completely possible to use AT-SPI without implementing ATK. The [[D-Bus]] migration made possible that [[Qt (software)|Qt]] added AT-SPI support. Qt implemented its own bridge to AT-SPI that was released in alpha status in August 2011 for testing purposes<ref>{{cite web|title=Accessibility on Linux|url=http://blog.qt.digia.com/blog/2011/08/23/accessibility-on-linux/|accessdate=2014-04-10|archive-url=https://web.archive.org/web/20140707193743/http://blog.qt.digia.com/blog/2011/08/23/accessibility-on-linux/|archive-date=2014-07-07|url-status=dead}}</ref> and it was integrated into Qt for general use a year later.<ref>{{cite web|title=Qt accessibility APIs|url=http://blog.qt.digia.com/blog/2012/06/18/qt-5-accessibility-apis/|accessdate=2014-04-10|archive-url=https://web.archive.org/web/20140707201604/http://blog.qt.digia.com/blog/2012/06/18/qt-5-accessibility-apis/|archive-date=2014-07-07|url-status=dead}}</ref>

== Development ==

AT/SPI is part of the GNOME Accessibility Framework that was released in 2001. The main development force behind ATK was the Accessibility Program Office (APO) of Sun Microsystems, Inc. (now Oracle) with contributions from many community members. When Oracle acquired Sun in 2010 they cut developer jobs of full-time developers working on GNOME accessibility components like the Accessibility Toolkit ATK and the Orca screen reader. Since then, it is mainly maintained by the GNOME community.

== Maintainers ==

ATK development has been led by their maintainers with the help of its community. The maintainers so far are:<ref>{{cite web | url = https://git.gnome.org/browse/at-spi2-core/tree/MAINTAINERS | title = AT-SPI's Maintainers file | accessdate = 2014-03-30 }}</ref>

Current:

* Mike Gorse

Previous:

* Mark Doffman

* Li Yuan

== Other uses ==

AT-SPI can also be used for automated testing of user interfaces, with tools such as [[Linux Desktop Testing Project]] and [[Dogtail]].<ref>{{cite web | url = https://wiki.linuxfoundation.org/accessibility/atk/at-spi/start | title = ATK/AT-SPI Special Interest Group | accessdate = 2020-11-26 }}</ref>

==Licensing==

AT-SPI is released under the [[GNU Library General Public License]] (LGPL) version 2.<ref name=license />

==See also==

* [[Category:Accessibility APIToolkit]] (ATK)

* [[Microsoft Active Accessibility]] (MSAA)

* [[Microsoft UI Automation]] (UIA)

* [[IAccessible2]]

==See also==

* {{slink|GNOME|Accessibility}}

== References ==

<references/>

== External links ==

[[Category:Accessibility API]]

* [http[freesoft://directory.fsf.org/project/atAt-spi/ |at-spi]], at the [[Free Software Directory]]

[[Category:GNOME]]

* [httphttps://projectswiki.gnome.org/accessibility/Accessibility GNOME Accessibility Project homepage]

* [https://web.archive.org/web/20140607010125/https://wiki.linuxfoundation.org/en/Accessibility/News/2010/02/08/AT-SPI2_release_0.1.6 ATSPI2] at the [[Linux Foundation]]

[[Category:Accessibility API]]

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[[Category:GNOME Accessibility]]

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