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TODO: magnification tools.
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|== GNOME color schemes ==||== Graphical User Interface ==
Currently, you can access the GNOME desktop with Orca. Please see the article [[Orca]] for more details.
=== Color Themes for accessibility ===
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|== gdm accessibility ==||=== gdm accessibility ===|
This page describes the accessibility stack of Debian and provides configuration hints for users. For development details, please look at accessibility-devel.
TODO: magnification tools.
Debian installer accessibility
The Debian installer has braille, speech, and contrast accessibility features which are documented in the installation manual .
Software speech is not yet supported in the standard installer, but an experimental image can be downloaded from http://people.debian.org/~sthibault/espeakup/
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.
The PC keyboard can also be used as a braille keyboard. In /etc/brltty.conf, uncomment key-table keypad, and restart brltty. One can then switch to braille by pressing insert+asterisk on the numpad, and switch back to normal by pressing insert+slash on the numpad. The default is to use the asdfjkl, keys as braille keys, but /etc/brltty/kbd-braille.kti can be modified to use other keys.
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.
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.
The Linux text console font can be tuned to get better accessibility: in /etc/default/console-setup, one can set FONTFACE to Terminus, in order to be able to select bigger fonts such as even FONTSIZE=32x16. That will of course reduce the amount of text displayed on the screen too. To fine-tune the exact amount of text displayed on the screen, SCREEN_WIDTH and SCREEN_HEIGHT can be set.
Graphical User Interface
Currently, you can access the GNOME desktop with Orca. Please see the article Orca for more details.
Color Themes for accessibility
The GNOME magnifier supports inverting colors. However, some people prefer other colors for the graphical environment or prefer to have only high contrast without all colors inverted. For this there is a package called gnome-accessibility-themes, where different themes are included. You can install it with
aptitude install gnome-accessibility-themes
These can then be selected in the preferences menu of GNOME.
The gdm graphical greeter supports accessibility, orca just needs to be enabled.
- It is enabled automatically when accessibility features were 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 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
Some users use the ibmtts or viavoice speech-synthetiser with orca, and they think that it is not convinient. According to them, the speech synthetiser is slow, its reactivity is slow, and it often crashes. The problem is that no alternative seems to exist, as gnome-speech is no longer supported by ibmtts' vendors.
However, the package who connects ibmtts to gnome-speech is under the LGPL. So, it was packaged and its name in Debian is gnome-speech-ibmtts.
How can you install it? Firstly, install ibmtts or viavoice speech synthetiser. Then, run (as root user):
apt-get install gnome-speech-ibmtts
NOTE: if you install ibmtts after the Debian package, you have to do:
otherwise, the viavoice config file will not be generated and orca will not see viavoice at the starting of the preferences menu.
NOTE: you likely will need to do, before the first reboot of orca, a backup of your ~/.local/share/orca, then delete the contents of its contents. Do this with:
cp -Rp ~/.local/share/orca ~/.local/share/orcabackup rm -r ~/.local/share/orca/*
You will need to recreate all your preferences (shortcuts, etc.).
This process allows users who do not want to use speech-dispatcher immediately to find a solution. Anyway, this solution is not ideal for the long-time future, as gnome-speech, or at-spi, will be deprecated with Gnome-3. It can however be a good transition. But it does not work for amd64 architectures. Only i386 is supported.
Note that you do not experience this issue if you migrate from lenny (5.0) to squeeze (6.0), as the migration maintains the necessary configuration so that ibmtts can be accessed via gnome-speech.
Tips and 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/
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!
Gnome for the Blind provides some information about gnome accessibility support
Accessibility blend, provide automatically-generated information on accessibility, like list statistics, and package descriptions and bugs.
Accessibility blend tasks, provides an insight in the set of packages that Debian ships for various needs (braille, speech, OCR, ...)