Accessibility Toolkit

ATK

Stable release	2.18 / September 21, 2015; 16 months ago (2015-09-21)
Development status	active
License	GNU LGPL (version 2)
Website

In computing, Accessibility Toolkit (ATK) refers in particular to the GNOME ATK, an application programming interface (API) for developing free/open source accessible applications for platforms such as Linux or OpenBSD.

One common nomenclature to explain an accessibility framework is a usual client-server architecture. In that way, assistive technologies (ATs) such as screen readers, would be the clients of that framework, and computer applications would be the server. In this architecture the client and server need to communicate with each other, usually using the IPC technology of the platform. Ideally the accessibility framework expose this to the client and server in a transparent way.

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 (Assistive Technology Service Provider Interface (AT-SPI)) and a different one for the server-side (ATK) due to historical reasons related to the underlying technologies.

The ATK abstract headers files are freely available to help developers who want to make their GUI toolkit accessible. Developers who use stock widgets of GUI toolkits that implements the ATK headers don't have to worry too much for making their applications accessible. However, if they develop their own widgets, they will have to ensure that they are exposing all the accessible information.

GAIL (GNOME Accessibility Implementation Library) was the name of the accessibility interfaces implementation defined by ATK for GTK+, the widget library of GNOME. Initially, GAIL was an independent module mapped to GTK+ but since GNOME 3.2, GAIL was merged into GTK+, so the ATK implementation is integrated into GTK+ and GAIL is deprecated.