<page xmlns="http://projectmallard.org/1.0/" xmlns:its="http://www.w3.org/2005/11/its" type="topic" id="tech-atk" xml:lang="ru">

  <info>

    <link type="guide" xref="tech" group="atk"/>

    <revision pkgversion="3.0" date="2011-04-05" status="candidate"/>

    <credit type="author copyright">

      <name>Shaun McCance</name>

      <email its:translate="no">shaunm@gnome.org</email>

      <years>2011–2012</years>

    </credit>

    <include xmlns="http://www.w3.org/2001/XInclude" href="cc-by-sa-3-0.xml"/>

    <desc>Accessibility toolkit to implement support for screen readers and

    other tools</desc>

  </info>

<title>ATK</title>

Accessibility is the process of ensuring your application can be

used by people with various disabilities.  Disabilities come in many forms:

visual impairments, movement impairments, hearing impairments, cognitive

and language impairments, and seizure disorders.  Many people have some

sort of disability, and making your application accessible will allow

more people to use it effectively, even if they are not disabled.

GNOME provides support for accessibility devices using the ATK framework,

which stands for Accessibility Tool Kit.  This framework defines a set of

interfaces to which graphical interface components adhere.  This allows, for

instance, screen readers to read the text of an interface and interact with its

controls.  ATK support is built into GTK+ and the rest of the GNOME platform,

so any application using GTK+ will have reasonable accessibility support for

free.

ATK solves the problem of plugging many different kinds of widgets (text

entries, text areas, buttons, menus) with many different types of accessibility

technologies (screen readers, braille displays, sip-and-puff control devices).

Instead of writing NxM interfaces, from each widget to each accessibility

device, one just has to expose a widget through ATK's interfaces.

Accessibility devices will in turn use these interfaces to query accessible

widgets.  For example, an aural screen reader and a braille display will both

use a standard "get the text contents" interface in ATK for all widgets with

textual information.

Nonetheless, you should be aware of accessibility issues when

when developing your applications.  Although GTK+ interfaces provide

reasonable accessibility by default, you can often improve how well

your program behaves with accessibility tools by providing additional

information to ATK.  If you develop custom widgets, you should ensure

that they expose their properties to ATK.  You should also avoid using

sound, graphics, or color as the sole means of conveying information

to the user; have redundant ways of providing this information instead of

relying on the user being able to perceive a particular medium.

The GNOME desktop ships with a number of accessibility tools which enable

users with disabilities to take full advantage of their desktop and

applications.  Applications that fully implement ATK will be able to work with

the accessibility tools.  These include a screen reader, a screen magnifier, an

on-screen keyboard, and <app>Dasher</app>, an innovative predictive text entry

tool.

<list style="compact">

  <item>
<link href="http://developer.gnome.org/accessibility-devel-guide/">GNOME Accessibility for Developers</link>
</item>

  <item>
<link href="https://developer.gnome.org/atk/stable/">ATK Reference</link>
</item>

</list>

</page>