Differences between revisions 1 and 8 (spanning 7 versions)
Revision 1 as of 2011-02-20 18:22:55
Size: 106
Comment:
Revision 8 as of 2011-02-21 00:01:54
Size: 4875
Comment:
Deletions are marked like this. Additions are marked like this.
Line 1: Line 1:
This page will document accessibility for users. For developers, please look at [[accessibility-devel]]. This page describes the accessibility stack of Debian and provides configuration hints for users. For development details, please look at [[accessibility-devel]].


== Links ==

 * [[http://www.debian.org/devel/debian-accessibility|Debian Accessibility team webpage]] provides official information. Only a few developers can modify it.
 * #debian-a11y on the oftc IRC network, come and chat with us!
 * [[http://delysid.org/gnome.html|Gnome for the Blind]] provides some information about gnome accessibility support
 * [[http://live.gnome.org/Orca|GNOME's screen reader and screen magnification software]]: [[Orca]]
 * [[http://blends.alioth.debian.org/accessibility/|Accessibility blend]], provide automatically-generated information on accessibility, like list statistics, and package descriptions and bugs.
 * [[http://blends.alioth.debian.org/accessibility/tasks/|Accessibility blend tasks]], provides an insight in the set of packages that Debian ships for various needs (braille, speech, OCR, ...)

== Debian installer accessibility ==

The Debian installer has braille, speech, and contrast accessibility features which are documented in [[http://www.debian.org/releases/stable/i386/ch05s02.html|the installation manual]] .

== Braille support ==

Braille device support is handled by [[http://packages.debian.org/stable/brltty|brltty]], which is started as a background daemon. It also provides screen reading support for the Linux text console. Screen reading support for the gnome desktop is provided by [[http://packages.debian.org/stable/gnome-orca|Orca]] . It does not drive braille devices itself, it "connects" to brltty via BrlAPI to do so. If Orca does not manage to output braille, make sure that

 * /etc/brlapi.key exists and contains something (the actual content doesn't matter, as long as it is not empty).
 * you have read permission on /etc/brlapi.key
 * brltty is up and running.

Some braille devices have an integrated braille keyboard. Brltty supports simulating keypresses on the text console. For proper simulation on Xorg (handle non-qwerty layouts, in particular), the [[http://packages.debian.org/stable/brltty-x11|brltty-x11]] package should be installed. It provides xbrlapi, which should be started at Xorg session startup, '''before''' starting orca.

Brltty also has very basic graphical screen reading support, which is limited to text fields, e.g. edit's main widget, or gnome-terminal's terminal. This is shipped in the [[http://packages.debian.org/stable/brltty-x11|brltty-x11]] package, and can be started by running

{{{brltty -b ba -x as}}}

at Xorg session startup. {{{-b ba}}} tells it to connect via BrlAPI to the already-running brltty that drives the actuall braille device. {{{-x as}}} selects the At-Spi driver, which performs graphical screen reading.

== Speech support ==

Debian provides a lot of speech syntheses, a list can be found in [[http://blends.alioth.debian.org/accessibility/tasks/speechsynthesis|the speechsynthesis blend task]]. Screen readers can often directly use some of the speech syntheses, or use generic interfaces, such as gnomespeech, or speech-dispatcher. Gnome-speech is mostly just a thin common layer. speech-dispatcher is more evolved: it runs as a daemon, which screen readers can connect to in order to emit speech. speech-dispatcher then has several modules to support various speech syntheses.

== gdm accessibility ==

The gdm graphical greeter supports accessibility, orca just needs to be enabled.

 * It is enabled automatically when accessibility features where enabled to access the Debian Installer
 * It can be enabled by clicking on the "accessibility" icon which brings a configuration panel.
 * It can be enabled by hand by running:

{{{su -s /bin/sh -c "gconftool-2 --type bool --set /desktop/gnome/applications/at/screen_reader_enabled true" Debian-gdm}}}

== Xorg issues ==

Xorg may not want to start if no actual physical screen is attached to
the video board. One can however use the dummy driver, which will not
make use of any graphical card, and still let the gnome desktop start
etc. Install the {{{xserver-xorg-video-dummy}}} package, and add the
following lines to /etc/X11/xorg.conf (create one if you don't have
any):

{{{
Section "Device"
    Identifier "noscreendevice"
    Driver "dummy"
EndSection
}}}

== Tips & tricks ==

Orca can be enabled to start automatically in the user session by hand by running

{{{
gconftool-2 --type bool --set /desktop/gnome/interface/accessibility true
gconftool-2 --type bool --set /desktop/gnome/applications/at/visual/startup true
}}}

It can also be useful to run

{{{gconftool-2 --type bool --set /desktop/gnome/sound/event_sounds true}}}

to enable desktop sound effects.

More tips are available on [[http://brl.thefreecat.org/wiki/]]

This page describes the accessibility stack of Debian and provides configuration hints for users. For development details, please look at accessibility-devel.

Debian installer accessibility

The Debian installer has braille, speech, and contrast accessibility features which are documented in the installation manual .

Braille support

Braille device support is handled by brltty, which is started as a background daemon. It also provides screen reading support for the Linux text console. Screen reading support for the gnome desktop is provided by Orca . It does not drive braille devices itself, it "connects" to brltty via BrlAPI to do so. If Orca does not manage to output braille, make sure that

  • /etc/brlapi.key exists and contains something (the actual content doesn't matter, as long as it is not empty).
  • you have read permission on /etc/brlapi.key
  • brltty is up and running.

Some braille devices have an integrated braille keyboard. Brltty supports simulating keypresses on the text console. For proper simulation on Xorg (handle non-qwerty layouts, in particular), the brltty-x11 package should be installed. It provides xbrlapi, which should be started at Xorg session startup, before starting orca.

Brltty also has very basic graphical screen reading support, which is limited to text fields, e.g. edit's main widget, or gnome-terminal's terminal. This is shipped in the brltty-x11 package, and can be started by running

brltty -b ba -x as

at Xorg session startup. -b ba tells it to connect via BrlAPI to the already-running brltty that drives the actuall braille device. -x as selects the At-Spi driver, which performs graphical screen reading.

Speech support

Debian provides a lot of speech syntheses, a list can be found in the speechsynthesis blend task. Screen readers can often directly use some of the speech syntheses, or use generic interfaces, such as gnomespeech, or speech-dispatcher. Gnome-speech is mostly just a thin common layer. speech-dispatcher is more evolved: it runs as a daemon, which screen readers can connect to in order to emit speech. speech-dispatcher then has several modules to support various speech syntheses.

gdm accessibility

The gdm graphical greeter supports accessibility, orca just needs to be enabled.

  • It is enabled automatically when accessibility features where enabled to access the Debian Installer
  • It can be enabled by clicking on the "accessibility" icon which brings a configuration panel.
  • It can be enabled by hand by running:

su -s /bin/sh -c "gconftool-2 --type bool --set /desktop/gnome/applications/at/screen_reader_enabled true" Debian-gdm

Xorg issues

Xorg may not want to start if no actual physical screen is attached to the video board. One can however use the dummy driver, which will not make use of any graphical card, and still let the gnome desktop start etc. Install the xserver-xorg-video-dummy package, and add the following lines to /etc/X11/xorg.conf (create one if you don't have any):

Section "Device"
    Identifier "noscreendevice"
    Driver     "dummy"
EndSection

Tips & tricks

Orca can be enabled to start automatically in the user session by hand by running

gconftool-2 --type bool --set /desktop/gnome/interface/accessibility true
gconftool-2 --type bool --set /desktop/gnome/applications/at/visual/startup true

It can also be useful to run

gconftool-2 --type bool --set /desktop/gnome/sound/event_sounds true

to enable desktop sound effects.

More tips are available on http://brl.thefreecat.org/wiki/