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

Contents

  1. Please help us help you
  2. Debian installer accessibility
  3. LiveCD accessibility
  4. Braille Support
  5. Speech Support
    1. Text Console
      1. BRLTTY
      2. Speakup
    2. Speech-Dispatcher
      1. Testing Speech-Dispatcher
    3. Audio Level
  6. Braille Embossers
    1. Generic Text Printers
    2. Using the Printer
    3. Known Issues
  7. Accessible boot
    1. Audible beeps
    2. Keyboard Shortcuts
    3. Complete Accessibility
    4. Grub magnification
  8. Console fonts
  9. Graphical User Interface
    1. Color Themes for accessibility
    2. Color Blindness
    3. Making cursor bigger
    4. Full Screen magnification support
      1. Option 1: Compiz
      2. Option 2: Resolution
      3. Option 3: Panning
      4. Option 4: Changing DPI
      5. Option 5: Desktop Environment
    5. Magnifying Glass
      1. Option 1: Kmag
      2. Option 2: Virtual Magnifying Glass
    6. Controlling the mouse from the keyboard
    7. gdm accessibility
    8. lightdm accessibility
    9. libreoffice accessibility
    10. 32bit applications accessibility
    11. Java accessibility
    12. Flatpak Accessibility
    13. Upgrading the Assistive Technology At Spi
  10. Virtualization
    1. Xen
    2. QEMU/KVM
  11. Troubleshooting
    1. No Speech After Login In GNOME
    2. No Sound
    3. BRLTTY/braille stops after boot
    4. Inaccessible GNOME 3 session / no fallback mode
    5. Xorg issues
    6. Run Pulseaudio as root
    7. Disable Pulseaudio
  12. Tips and tricks
    1. speakup and package configuration questions
    2. Accessibility in chroots
    3. Screen off
      1. Prevent Automatic Monitor Reactivation
    4. Sound effects On The GNOME Desktop
    5. faster speaking eSpeak
    6. More Tips
  13. Related links

Please help us help you

It would be very helpful for disabled users to provide test scenarios, so that non-disabled developers can know how to test accessibility packages, and thus help the accessibility team. Please see <20131008210138.GA9212@type.youpi.perso.aquilenet.fr> for details.

Debian installer accessibility

The Debian installer has braille, speech, and contrast accessibility features which are documented in the installation manual for the stable release, as well as the current draft for next upload (also on https://salsa.debian.org/installer-team/installation-guide/tree/master/en/boot-installer). Specifically, here is the support status for various releases:

Braille USB devices are detected automatically; serial devices need configuration at boot.

All accessibility support is available on all images except the non-gtk netboot mini.iso image, which does not have speech support. For instance, one can use the CD-1 image from https://cdimage.debian.org/debian-cd/current/amd64/iso-cd/ or the DVD-1 image from https://cdimage.debian.org/debian-cd/current/amd64/iso-dvd/.

Software speech is supported since Debian Wheezy (Debian 7): when you get to the boot menu (a beep should be emitted to indicate this), simply press 's' and enter, as of Debian 12 that is the default action taken from the menu after 30 seconds if no keyboard input has been received. It can also be triggered from the win32-loader by choosing the expert installer, the graphical mode installation, and by appending speakup.synth=soft to the kernel command line. Note, however, that the windows boot menu is not accessible; one has to press down and enter while it is showing up at boot (for 30s, by default).

Starting from Debian Stretch (Debian 9), expert installation, rescue mode, and automatic installation are also available with accessibility support. The procedure slightly differs for UEFI and BIOS systems: BIOS systems require pressing return after each command, UEFI systems don't. Please use the instructions below as appropriate. After the boot has completed, a beep should be emitted on BIOS systems, while UEFI systems will beep twice. To access these advanced functionalities, one has to first enter the "advanced" submenu from the boot menu by typing 'a' (on BIOS systems this has to be followed by return; on UEFI systems that must not be done). To enable speech, pressing 's' (again, followed by return on BIOS systems but not on UEFI systems) will enable speech support. Now various shortcuts are available: 'x' for expert installation, 'r' for rescue mode, or 'a' for automated installation. Again, these need to be followed by return when using a BIOS system. Also, all of this is with a qwerty keyboard layout.

Starting from Debian Buster (Debian 10), 'd' can be used in the boot menu to enable the high-contrast (dark) theme.

Some recent Intel sound cards need non-free firmware, so you may need to use the unofficial image that includes them (from https://cdimage.debian.org/cdimage/unofficial/non-free/cd-including-firmware/current/amd64/).

If the speech volume level is too low, you can type ?CapsLock-2 to make it higher (and ?CapsLock-1 to make it lower). If you prefer a faster speech rate, you can type ?CapsLock-6 (or ?CapsLock-5, to make it slower).

When installation is done via braille or speech, the same braille and speech parameters will get enabled on the installed system. Orca will also be enabled for the user account that is created at installation.

Speech synthesis should come up within the installer. If it does not, please provide enough information to let us find out where the bug is.

First and foremost, we need the exact URL you used to download the installer image; otherwise, we won't ever manage to find a bug which could only exist on the image you have used (and which has to be fixed too!).

Inside the installer, press alt-f2 to switch to a shell console, press enter to start the shell, and type

amixer -c 0 scontrols

amixer -c 1 scontrols

cat /proc/asound/cards

echo /sys/class/sound/card*/id

cat /sys/class/sound/card*/id

lsmod

dmesg | grep firmware

cat /var/run/espeakup.card

amixer -c 0 contents

amixer -c 1 contents

(for these, the important sections to report are the Master, Headphone, Speaker, and PCM)

Then, post the output to debian-accessibility@lists.debian.org, so we can know whether a sound card was detected and what the volume level names are. If only an error message shows up, or if you do not have resources to be able to read the shell console, please try to run a live CD, make sound work with it, and post the output of the same commands above to debian-accessibility@lists.debian.org so we can know what sound driver is missing.

If speech synthesis does not come up at reboot into the installed system, we also need information to find out where the bug is. Please post to debian-accessibility@lists.debian.org the results of the same command above, plus

cat /etc/default/espeakup

To pre-record some boot options and thus avoid typing them blindly, one can remaster an image by using the script below:

https://people.debian.org/~sthibault/remaster-append.sh

Testing accessibility in the Debian installer is documented on the Debian installer accessibility page.

LiveCD accessibility

The GNOME LiveCD images from https://www.debian.org/CD/live/ have screen reader support. At the boot menu, a beep should be emitted to indicate that one has to press enter. The desktop then launches (TODO: add beep) and one can press super-alt-s (aka windows-alt-s) to start Orca.

Braille Support

Braille device support is handled by brltty, which is started as a background daemon. Most displays work under brltty, connected via either a serial port, USB, or Bluetooth. Details on supported braille devices can be found on the brltty website (https://brltty.app/). Brltty also provides screen reading support for the Linux text console.

Screen reading support for GNOME and other desktop environments is provided by Orca. It does not control braille devices itself; it connects to brltty via BrlAPI to do so. If Orca does not manage to output braille, make sure that:

Some braille devices have an integrated braille keyboard. Brltty supports simulating keypresses on the text console. For proper simulation on Xorg (handling 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 numeric keypad. Switch back to normal by pressing insert+slash on the keypad. The default is to use the asdfjkl, keys as braille keys, but /etc/brltty/kbd-braille.kti can be modified to use other keys.

One can also type Unicode braille patterns (not letters, pure braille, shown as such on the screen) thanks to the console-braille package, which includes keyboard layouts and the setbrlkeys program to load them easily.

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 a2

at Xorg session startup. The -b ba option tells it to connect via BrlAPI to the already-running brltty that drives the actuall braille device. The -x a2 option selects the At-Spi driver, which performs graphical screen reading.

Speech Support

Debian provides a lot of software speech synthesizers. A list can be found in the speechsynthesis blend task. Screen readers can often directly use some of the speech synthesizers, or use generic interfaces such as speech-dispatcher. speech-dispatcher runs as a daemon. Screen readers can connect to this in order to emit speech. speech-dispatcher then has several modules to support various speech syntheses.

Some of them are free both as in free speech and free beer:

Some of them are free as in free beer but not free speech

Others are non-free:

Speech synthesizers are known to have issues with pulseaudio (especially on the command line). It is recommended to run pulseaudio as root or disable/remove pulseaudio, as described in #Run_Pulseaudio_as_root or #Disable_Pulseaudio.

Text Console

Software speech synthesizers are supported on the text console. There are three screen readers within Debian which can make use of them: speakup, brltty, and fenrir.

BRLTTY

BRLTTY offers mature screen reading support for the console, including speech. You have the choice of using espeak directly or via speech-dispatcher. These can be installed with the brltty-espeak or the brltty-speechd package, respectively.

It is necessary to activate the speech driver in the configuration of BRLTTY. Open /etc/brltty.conf and edit it:

1. When using brltty-espeak, uncomment or insert the following line:

speech-driver es

2. When using brltty-speechd, uncomment or insert the following line:

speech-driver sd

Afterwards, reload BRLTTY with sudo service brltty restart.

Speakup

Speakup is an in-kernel screen reader for the Linux text console. See the Speakup User's Guide for details.

The simplest way to use Speakup is by means of the espeakup package. This plugs the espeak software synthesizer directly into the in-kernel screen reader. You need to add speakup_soft to /etc/modules in order to get the kernel part loaded so that espeakup can work. The configuration file (/etc/default/espeakup) can be used to set both the voice and card to be used.

Another way is use Speakup is by installing speech-dispatcher and speechd-up. Speech-dispatcher needs to be started in system-wide mode: /etc/default/speech-dispatcher needs to contain RUN=yes.

Please see the section about speech-dispatcher for more details.

Hardware speech synthesizers are also supported on the text console through the speakup drivers. Before Debian Buster (10), however, this required disabling of the the 8250 serial port driver, by setting this variable in /etc/default/grub:

GRUB_CMDLINE_LINUX="8250.nr_uarts=0"

One can then, for instance, add this line in /etc/modules to get a speakup module loaded:

speakup_dectlk

Speech-Dispatcher

ToDo: needs to be written. Document:

Also, if you do not have pulseaudio installed, you need to make speech-dispatcher revert to Alsa: in /etc/speech-dispatcher/speechd.conf, uncomment the line AudioOutputMethod and set it this way:

AudioOutputMethod "alsa"

Testing Speech-Dispatcher

You can test whether speech-dispatcher works by running

spd-say "some text"

Or, if you want to test a specific module such as espeak:

spd-say -o espeak "some text"

If these do not produce sound, check out the log files in $XDG_RUNTIME_DIR/speech-dispatcher/log, which can possibly be one of /run/user/1000/speech-dispatcher/log, ~/.cache/speech-dispatcher/log, or /tmp/runtime-$USER/speech-dispatcher/log. Note that $USER needs to be replaced by the actual user name.

Audio Level

Starting from Stretch (Debian 9), the audio levels are reset to a default value at bootup. If you want to change that default value, set the audio levels to the desired value (e.g. using alsamixer from the alsa-utils package) and save the settings by running alsactl store as root.

Braille Embossers

Embossers are supported by CUPS (Common Unix Printing System) drivers, available in the cups-filters package. For supported embossers, a dedicated driver is shipped with cups-filters, and other printers can use the text-mode embossing functionality. Please read the cups-filters README before proceeding. It can be found at /usr/share/doc/cups-filters/README.gz. In it, search for "braille".

Embossers are added like normal printers. Use either your desktop environment's method or go in a browser to http://localhost:631.

Generic Text Printers

You can add an text-only embosser just like a printer.

During the driver selection, choose the "Generic" maker and choose the "Generic Braille embosser" model. This will provide several options to set formatting, page numbering, etc.

If your embosser doesn't do so automatically, you may need to reformat your text to the width of the paper by using the fmt command. For example, to set a width of 32 columns (A4), use: 

fmt -w 32 < test.txt > test2.txt

Using the Printer

It is advised to print from the command-line, as the graphical printer facilities use PDF as intermediate format and hence destroy the braille formatting. To print from the command-line, use:

lp test2.txt

or

lp mydoc.odt

Known Issues

If something doesn't work as expected, have a look at /var/log/cups/error.log which usually contains useful hints on what might be wrong. The following issues are known:

Accessible boot

Audible beeps

GRUB can be made to beep when it is ready to take keyboard presses. In /etc/default/grub, uncomment or add the following line: 

GRUB_INIT_TUNE="480 440 1"

and run update-grub.

Keyboard Shortcuts

It is possible to assign keyboard shortcuts to boot menu entries.

For instance, to make the letter 'a' a shortcut for an entry, add --hotkey=a just after the menuentry word of that entry: 

menuentry --hotkey=a 'Linux' {
   ...
}

However, this does not work for the auto-generated boot entries (from update-grub). As a workaround, you can create manual entries in /etc/grub.d/40_custom and assign shortcuts there. If you are unsure of the format, you can look for menuentry in /boot/grub/grub.cfg and copy this as a template.

Complete Accessibility

An option to get a completely accessible bootloader is to use petitboot. The principle is to make the normal bootloader (e.g. Grub) boot Linux normally, but making it start petitboot and brltty. Petitboot provides the list of kernels to boot, and permits parameters to be appended. It then uses kexec to boot the desired kernel with the desired options.

However, this does not support booting Windows, only Linux.

First, install the petitboot package, create a /boot/petitboot.sh file containing for instance: 

   1 #!/bin/sh
   2 /bin/mount none /var -t tmpfs
   3 /bin/mount none /tmp -t tmpfs
   4 /etc/init.d/udev start
   5 /usr/sbin/pb-discover &
   6 /sbin/brltty
   7 /usr/sbin/petitboot-nc -l /tmp/log

And make it executable:

chmod +x /boot/petitboot.sh

Then, create a boot entry for petitboot. For instance, copy/paste from /boot/grub/grub.cfg a Linux entry (which is known to boot fine) to the end of /etc/grub.d/40_custom , append at the end of the linux line (that specifies the vmlinux file) init=/boot/petitboot.sh , and name the menu entry petitboot. You can also choose a hotkey for the entry. So for instance it should look like: 

menuentry 'petitboot' --hotkey=p --class debian --class gnu-linux --class gnu --class os {
    ...
    echo 'Loading Linux <version> ...'
    linux /boot/vmlinuz-<version> root=blabla ro init=/boot/petitboot.sh
    echo 'Loading initial ramdisk ...'
    initrd /boot/initrd.img-<version>
}

You may want to keep a backup of the known-to-boot kernel in a safe place, and use that path instead of the Debian-provided file whose upgrades might break.

Eventually, run update-grub to update /boot/grub/grub.cfg.

That way, at boot when you get the grub beep, you have the option to press the "End" key then "Enter", or press the hotkey "p", and that will boot linux, brltty, and petitboot.

If after good testing you really feel safe enough, you can make it the default in grub: in /etc/default/grub, set

GRUB_DEFAULT="petitboot"

and re-run update-grub . You still have the option, when grub beeps, to press "Begin" then "Enter" to boot without petitboot.

Grub magnification

Grub does not include magnification, but the font size can be increased easily by generating a font file: 

grub-mkfont -s 60 -o /boot/grubfont.pf2 /usr/share/fonts/truetype/dejavu/DejaVuSansMono.ttf

Size 60 can be changed to better fit your needs.

And adding to /etc/default/grub the lines 

GRUB_FONT="/boot/grubfont.pf2"

to actually use the font.

Note that this can only work in the graphical output, so make sure you do *not* have this line uncommented: 

GRUB_TERMINAL=console

update-grub needs to be rerun after modifying /etc/default/grub. It does not need to be re-run if you re-run grub-mkfont to set a different font size.

Console fonts

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.

The console-braille package provides braille fonts, which you can use to type unicode braille patterns, and show braille on the physical screen. This is incompatible with using FONTFACE, as you will need to specify both the normal font and the braille font in the FONT variable, see example in /etc/default/console-setup .

Another possibility is to use fbterm, which has a -s option to generate big font sizes:

fbterm -s 40

Fbterm is however not compatible with brltty and speakup.

Graphical User Interface

Currently, you can access the GNOME, MATE, XFCE, LXDE, LXQt desktops with Orca. Please see the article Orca, the GNOME Orca documentation and the accessibility section of GNOME Help for more details. For GNOME 3, it is useful to read the GNOME shell shortcut guide

As a first start, one thing you need to know is that the application menu can be opened with the alt-f1 shortcut.

The simplest way to install these graphical user environments is to install the corresponding tasks, for instance: 

apt install task-gnome-desktop

Another, lighter, way is to install Xorg and the environment meta-package by hand, but you will probably miss quite a few things. For instance: 

apt-get install xorg xserver-xorg-video-all xserver-xorg-input-all desktop-base menu gnome-core

And also make sure to have orca installed to access it: 

apt-get install orca

Each desktop has a way to enable accessibility. You can also do it by hand, see among the tips&tricks below.

For KDE qt4 applications accessibility such as vlc player, the qt-at-spi package needs to be installed, and the QT_ACCESSIBILITY environment variable has to be set to 1: 

export QT_ACCESSIBILITY=1

(this should already be done by /etc/X11/Xsession.d/90qt-a11y)

Note: not every application written using the gtk or qt toolkits is accessible, even when accessibility is enabled. For example, spotify remains not accessible.

Note: the default configuration of speech-dispatcher uses pulseaudio, which will refuse to run as root. This means that when logging in as root, the graphical session will not get speech output. A way to circumvent this is to configure speech-dispatcher to use the ALSA output: in /etc/speech-dispatcher/speechd.conf, set the following line: 

AudioOutputMethod= "alsa"

Color Themes for accessibility

To enable high contrast or to invert colours, a package called gnome-accessibility-themesexists , 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.

Colors can be inverted using xcalib too, i.e.: 

xcalib -i -a

will just invert the whole desktop.

Colors can be tuned in the apt/debconf configuration interface, by adding this line to /root/.bashrc for instance: 

export NEWT_COLORS='root=,black roottext=white,black window=,black textbox=white,black border=white,black button=white,black checkbox=white,black listbox=white,black'

Color Blindness

For colorblindness, the KDE magnifier program includes options to alter the color of just a region (not the whole screen). It has settings for protanopia, deuteranopia, titranopia, and achromatopsia.

Making cursor bigger

Installing the big-cursor package should be making the cursor bigger in various cases.

On the MATE desktop, one can use the following to set a bigger cursor: 

gsettings set org.mate.peripherals-mouse cursor-size 48

(or values even bigger than 48)

Both a black and a white cursor can be configured:

Full Screen magnification support

There are several options for full screen magnification. Pick the one that works best for you.

Option 1: Compiz

Enhanced magnification support is provided by the ezoom plugin of Compiz

Option 2: Resolution

The simplest way is to lower the screen resolution: xrandr -s 800x600

To reset the screen resolution, use: xrandr -s 0

Option 3: Panning

It is possible to zoom in without changing the screen resolution. Only a portion of the screen will be visible, so move the mouse to the screen edges to pan around.

To enable panning: xrandr --output VGA1 --mode 640x480 --fb 1280x1024 --panning 1280x1024

To turn off panning: xrandr -s 0

Option 4: Changing DPI

A method which works for some toolkits is to tell the Xserver that it had a higher resolution display than it really has:

To change DPI: xrandr --dpi 200

which will make everything basically two times bigger (200 dpi instead of the standard 96dpi or even 75dpi). That will notably work in Qt.

For gtk2, one can put the following in ~/.gtkrc-2.0: 

gtk-font-name = "DejaVu Sans 20"
gtk-cursor-theme-size = 64
gtk-icon-sizes = "gtk-menu=48,48 : gtk-button=48,48 : gtk-dialog = 128,128"

style "default"
{
        GtkRange::slider_width = 56
        GtkRange::stepper_size = 56
        GtkPaned::handle-size = 20
        GtkCheckMenuItem::indicator-size = 48
        GtkCheckButton::indicator-size = 48
        GtkOptionMenu::indicator-size = 48
        GtkTreeView::indicator-size = 48
        GtkTreeView::expander-size = 40
}

class "GtkWidget" style "default"

For gtk3, one can set this environment variable:

export GDK_SCALE=2

Other toolkits may need other configuration. Ideally they'd just pick up the DPI...

Option 5: Desktop Environment

The previous solutions work for any Debian system. However, depending upon which desktop environment you have installed, you may also have a simple graphical way to enable zooming. For example, Gnome-Shell and Cinnamon both include a Universal Access icon universalaccess.svg on their dock with a menu option to enable full screen zoom & pan. The Cinnamon magnifier however does not support focus tracking, the gnome-shell one does.

Magnifying Glass

Some people prefer using a virtual magnifying glass instead of magnifying the entire screen. The screen resolution is not changed, instead a small window is added which shows a magnified version of a portion of the screen. Usually you can choose where to be magnify by dragging inside the window or by having the program always magnify the region around the mouse. There are again different possibilities, you are free to choose from the following:

Option 1: Kmag

The KDE screen magnifier can be installed with apt-get install kmag.

Kmag is simple to use. It will take up more disk space (>200MiB) if you don't already have KDE installed. Although designed for KDE, Kmag works with any desktop environment, including Gnome and Cinnamon.

Option 2: Virtual Magnifying Glass

If you have trouble reading only occasional words, you may prefer Virtual Magnifying Glass (VMG). Its advantage is that it is usually not visible, unlike programs such as kmag which create a window that always covers part of your screen. Clicking on the VMG icon in the tray shows a zoomed lens around your mouse pointer. Moving the mouse, moves the lens. Clicking anywhere closes the program. (Tip: To change the zoom level, roll the mouse-wheel.)

VMG is available from Stretch (Debian 9) and later. It can be installed fine on Jessie systems too, the .deb can be obtained on https://packages.debian.org/sid/vmg , and installed with 

dpkg -i vmg_3.7.1-1_amd64.deb
apt-get -f install

Controlling the mouse from the keyboard

One can use the keypad to move the mouse. One needs to enable the xkb option keypad:pointerkeys for that. This can be temporarily achieved by: 

setxkbmap -option keypad:pointerkeys

And permanently, by adding the line 

Option "XkbOptions" "keypad:pointerkeys"

to /etc/X11/xorg.conf.d/00-keyboard.conf

To actually enable it, one has to type shift-numlock. The numpad keys then move the mouse and keypad 5 simulates the mouse click. '/', '*' and '-' can be used to switch between left, middle, and right button. '0' and 'del' hold and release the button. Type shift-numlock to get a normal numpad again.

gdm accessibility

The gdm graphical greeter supports accessibility, orca just needs to be enabled. But in Lenny the default installed gdm doesn't support this feature. So for Lenny you need, firstly, to remove gdm, and install gdm3 instead. Squeeze (Debian 6) and later already use gdm3 by default.

Then, you can enable orca with either of four ways: 

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

or for Wheezy (Debian 7) and later: 

su -s /bin/sh -c 'eval $(dbus-launch) ; export DBUS_SESSION_BUS_ADDRESS DBUS_SESSION_BUS_PID ; GSETTINGS_BACKEND=dconf gsettings set org.gnome.desktop.a11y.applications screen-reader-enabled true' Debian-gdm || true

lightdm accessibility

The lightdm graphical greeter supports accessibility, orca just needs to be enabled. Create the directory /etc/xdg/lightdm/lightdm.conf.d, then create the file /etc/xdg/lightdm/lightdm.conf.d/80_orca-dm-wrapper.conf and write the following in it: 

[SeatDefaults]
greeter-wrapper=/usr/bin/orca-dm-wrapper

Since Debian 11, orca can also be started on the fly with the F4 keyboard shortcut.

libreoffice accessibility

To make libreoffice accessible, one has to install libreoffice-gtk3.

32bit applications accessibility

If you are running a 64bit system, and use some 32bit applications, having libatk-adaptor installed will not be enough for making 32bit applications accessible: you need to also install the 32bit version of the package. If you have not done it already, enable i386 package installation, as documented in great details on Multiarch/HOWTO: 

dpkg --add-architecture i386

Then update the APT database: 

apt-get update

and you can now install the 32bit version of the GTK bridge: 

apt-get install libatk-adaptor:i386 libgail-common:i386

and of the Qt bridge: 

apt-get install qt-at-spi:i386

Java accessibility

To access Java applications, one needs to install the libatk-wrapper-java package. Unfortunately, in Debian versions 11 and 12, OpenJDK has disabled accessibility by default. It has to be reenabled by hand. The path varies slightly by your used version number, just look in /etc for a directory starting with java. If found, adapt the following path and open it in a text editor: /etc/java-17-openjdk/accessibility.properties and uncomment the following line (the # in front needs to be removed): 

assistive_technologies=org.GNOME.Accessibility.AtkWrapper

Also, only the GTK look and feel has accessibility support, so in the file /etc/java-6-openjdk/swing.properties for Debian 7 (Wheezy) or /etc/java-7-openjdk/swing.properties for Debian 8 (Jessie) the following line must be uncommented (the # in front needs to be removed): 

swing.defaultlaf=com.sun.java.swing.plaf.gtk.GTKLookAndFeel

Flatpak Accessibility

A flatpak allows to install third-party software from package sources other than Debian. Installed applications are isolated via so called containers, which means that the required accessibility infrastructure is not available by default to Flatpak applications. This is for security reasons, as there seems to be no fine-grained way to pass-through accessibility information. If the Flatpak source is trusted, accessibility can be "activated" by enabling the usage of the session bus:

1. Find your application ID with the command

flatpak list

2. In the second column, an identifier such as "org.foo.baz" is shown, copy it.

3. Execute

flatpak run --socket=session-bus THEAPPIDENTIFIER

replacing THEAPPIDENTIFIER with the copied identifier.

Upgrading the Assistive Technology At Spi

The assistive technology At Spi is the base for graphical interface accessibility, including Orca. To benefit from the latest advances in it, it is often useful to try a more recent version. Debian does not update to newer upstream versions of software, once released. An exception is the backports service that provides selected packages in more recent versions for a stable system.

For a Debian 12 ‘Bookworm’ system, add this to your /etc/apt/sources.list : 

deb http://ftp.debian.org/debian bookworm-backports main

or use extrepo: 

sudo apt install extrepo
sudo extrepo enable debian_backports

and run 

apt-get update
apt-get install at-spi2-core/bookworm-backports gir1.2-atspi-2.0/bookworm-backports gir1.2-atk-1.0/bookworm-backports libatk-adaptor/bookworm-backports python3-pyatspi/bookworm-backports orca/bookworm-backports libatk-wrapper-java-jni/bookworm-backports libatk-wrapper-java/bookworm-backports

If you need the development packages (e.g. to build Orca), you can run 

apt-get install libatspi2.0-dev/bookworm-backports libatk-bridge2.0-dev/bookworm-backports

For a Debian 11 ‘Bullseye’ system, add this to your /etc/apt/sources.list : 

deb http://ftp.debian.org/debian bullseye-backports main

or use extrepo: 

sudo apt install extrepo
sudo extrepo enable debian_backports

and run 

apt-get update
apt-get install at-spi2-core/bullseye-backports gir1.2-atspi-2.0/bullseye-backports gir1.2-atk-1.0/bullseye-backports libatk-adaptor/bullseye-backports python3-pyatspi/bullseye-backports orca/bullseye-backports libatk-wrapper-java-jni/bullseye-backports libatk-wrapper-java/bullseye-backports

If you need the development packages (e.g. to build Orca), you can run 

apt-get install libatspi2.0-dev/bullseye-backports libatk-bridge2.0-dev/bullseye-backports

For a Debian 10 ‘Buster’ system, add this to your /etc/apt/sources.list : 

deb http://ftp.debian.org/debian buster-backports main

and run 

apt-get update
apt-get install at-spi2-core/buster-backports gir1.2-atspi-2.0/buster-backports gir1.2-atk-1.0/buster-backports libatk-adaptor/buster-backports python3-pyatspi/buster-backports orca/buster-backports libatk-wrapper-java-jni/buster-backports libatk-wrapper-java/buster-backports

If you need the development packages (e.g. to build Orca), you can run 

apt-get install libatspi2.0-dev/buster-backports libatk-bridge2.0-dev/buster-backports

For a Debian 9 ‘Stretch’ system, add this to your /etc/apt/sources.list : 

deb http://ftp.debian.org/debian stretch-backports-sloppy main

and run 

apt-get update
apt-get install at-spi2-core/stretch-backports-sloppy gir1.2-atspi-2.0/stretch-backports-sloppy gir1.2-atk-1.0/stretch-backports-sloppy libatk-adaptor/stretch-backports-sloppy python3-pyatspi/stretch-backports-sloppy orca/stretch-backports-sloppy libatk-wrapper-java-jni/stretch-backports-sloppy libatk-wrapper-java/stretch-backports-sloppy

If you need the development packages (e.g. to build Orca), you can run 

apt-get install libatspi2.0-dev/stretch-backports-sloppy libatk-bridge2.0-dev/stretch-backports-sloppy

Eventually, restart your graphical session to get the new software running or reboot your system.

Virtualization

Virtualizations tools are more or less accessible

Xen

Xen uses a command-line interface, so is of course accessible. Setting up a Xen environment is however not so easy. See the Debian Xen wiki pages.

QEMU/KVM

QEMU/KVM can be run in text-mode, by using the -display curses option. Of course, when the guest is in graphical mode, the text interface will not show anything useful, and a screen reader will still be needed inside the guest.

To let that screen reader emit speech, the -device ac97 option can be used to provide the guest with a virtual sound board (-soundhw ac97 for older QEMU/KVM versions)

To let the screen reader emit braille, the -usbdevice braille option can be used to provide the guest with a virtual Baum braille device. The braille rendering will be done through the host brltty daemon.

Another way for braille is to pass-through a USB braille device. For instance, if on the host lsusb reports the braille device as: 

Bus 001 Device 002: ID 0403:fe72 Baum

Giving the -usbdevice host:0403:fe72 option will give the USB device to the guest, i.e. you must first make sure that nothing like brltty in the host uses it, then run qemu/kvm, and then a brltty daemon inside the guest can access the physical device, as if it was connected to the virtual machine.

Of course, if one has two USB braille devices, one can be used by a brltty running on the host, and the other by a brltty running in the guest.

Troubleshooting

No Speech After Login In GNOME

If Orca only says "Welcome to Orca" and seems to be silent then, you are actually on an empty desktop. To get the focus, press Alt+F1 for the menu or Alt+F2 for the run-dialog.

No Sound

In rare cases, the system might boot with the volume being too low or with a muted sound card. The following commands might solve this: 

amixer set Master 50%+
amixer set PCM 50%+
amixer set Master unmute

Note: the 50% is an example value. You can use any other value that suits you.

BRLTTY/braille stops after boot

In Wheezy (Debian 7) there has been added a program called modemmanager which scans serial (and possibly usb2serial) devices to detect it as a modem. Unfortunately this destroys the communication with braille displays connected via those ports. Just 

apt-get remove modemmanager

to repair this issue.

Inaccessible GNOME 3 session / no fallback mode

It can happen that you end up in a inadequately accessible GNOME 3 session. For instance, if you press alt+f1 for the menu, nothing is spoken. This has to do with the not-yet well accessible GNOME shell. Please see below how to resolve this problem.

Debian Jessie (GNOME >= 3.8)

In Debian Jessie with GNOME version >= 3.8, there is a mode called GNOME classic. This one uses the GNOME shell directly to achieve GNOME 2 alike user experience. When using startx, you can set up your .xinitrc as follows to use this mode: 

if [ -d /etc/X11/xinit/xinitrc.d ]; then
  for f in /etc/X11/xinit/xinitrc.d/*; do
    [ -x "$f" ] && . "$f"
  done
  unset f
fi

exec gnome-session --session=gnome-classic

Xorg issues

Xorg may not want to start if no actual physical screen is attached to the video board. This should be reported to the video driver being used, you can cite this mail for the rationale behind fixing it.

In the meanwhile, one can 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

The support is however broken since Squeeze (debian 6), see 696965, the following patch can be applied to Xorg to fix it: 

diff --git a/src/dummy_driver.c b/src/dummy_driver.c
index 6062c39..566a006 100644
--- a/src/dummy_driver.c
+++ b/src/dummy_driver.c
@@ -813,7 +813,7 @@ dummyDriverFunc(ScrnInfoPtr pScrn, xorgDriverFuncOp op, poin
     switch (op) {
        case GET_REQUIRED_HW_INTERFACES:
            flag = (CARD32*)ptr;
-           (*flag) = HW_SKIP_CONSOLE;
+           (*flag) = 0;
            return TRUE;
        default:
            return FALSE;

Run Pulseaudio as root

To be able to run speech both at the text console and in graphical sessions, one can run pulseaudio as root. This is not recommended by upstream pulseaudio so one has to tinker a bit:

put this into /root/.config/pulse/client.conf : 

default-server = unix:/tmp/pulse.sock
autospawn = no

and put this into $HOME/.config/pulse/default.pa 

.include /etc/pulse/default.pa
load-module module-native-protocol-unix auth-anonymous=1 socket=/tmp/pulse.sock

Disable Pulseaudio

Pulseaudio can cause problems when running a console screen reader as root that is using ALSA, as for instance Speakup or BRLTTY. Apart from running Pulseaudio as root, it can be disabled as well.

There are two options available. The first one works for MATE or an even more light-weight desktop environment by removing the package: 

sudo apt remove pulseaudio

For other desktop environments like GNOME it is impossible to remove Pulseaudio. Disabling works as follows:

1. Execute the command 

dpkg-divert --add --rename /usr/share/alsa/pulse-alsa.conf

2. Instruct pulseaudio not to spawn itself automatically. Edit /etc/pulse/client.conf and search for a line like: 

; autospawn = yes

and change it into 

autospawn = no

Hint: you should reconfigure Speech-Dispatcher to use a different audio output method. Edit /etc/speech-dispatcher/speechd.conf and change the line 

# AudioOutputMethod "pulse"

to 

AudioOutputMethod "libao"

You need to restart Speech-Dispatcher: 

killall speech-dispatcher; speech-dispatcher

If you configured Speech-Dispatcher to run system-wide, the command to restart it is: 

systemctl restart speech-dispatcher

and you should add root to the audio group using sudo adduser root audio.

Tips and tricks

speakup and package configuration questions

When using the speakup screen reader, the default frontend for package configuration is not convenient. One can switch to the Readline frontend by default by running 

dpkg-reconfigure debconf

and choose Readline. One can also choose the frontend for just a session by running 

export DEBIAN_FRONTEND=readline

Accessibility in chroots

In order for applications to be accessible from within chroots, they need to have access to the at-spi bus. This bus lives in both /tmp and $HOME, so the following is needed, in addition to the usual at-spi configuration inside the chroot: 

mount /tmp /where/the/chroot/is/tmp -o bind
mount /home /where/the/chroot/is/home -o bind

And as usual, the DISPLAY and XAUTHORITY environment variable should set to the value they have outside the chroot, in order to access the X display.

Screen off

To save battery or to get some privacy, it may be desirable to turn off the monitor. There are three approaches, but not all of them work with every computer. The first and second approach require administrator privileges and the third one is a bit more involved.

  1. Install brightnessctl and use these commands:

    • To switch the monitor off: brightnessctl s 0%

    • To switch the monitor on: brightnessctl s 100%

    • Also see the section on automatic monitor deactivation.

  2. Install the package vbetool and use these commands:

    • To switch the monitor off: sudo vbetool dpms off

    • To switch the monitor on: sudo vbetool dpms on

    • It is also a good idea (but not required) to add a setting to your sudoers file to allow this command to be executed without password prompt. Add in

      /etc/sudoers:

      user   ALL=(root) NOPASSWD: /usr/sbin/vbetool
      (where "user" must be replaced with the user name.)

    • Also see the section on automatic monitor deactivation.
  3. This approach differs for the console and X.
    • Console:

      • To switch the monitor off: setterm -blank force

      • To switch the monitor on: setterm -blank poke

      • The commands need to be run directly on the Linux console. When using screen or tmux, the output must be directed to the used TTY, e.g. for tty1:
        sudo sh -c 'setterm -blank force > /dev/tty1'<br />

        If this fails with "setterm: cannot force blank: Inappropriate ioctl for device", you need to detach from your terminal multiplexer, clear the screen, e.g. with clear, run the above command, and attach again.

    • Graphical X11 interface:
      The following script allows to toggle the display off and on again: 

         1   #!/bin/sh
   2   output=$(xrandr | grep ' connected ' | awk '{print $1}' | head -1)
   3   screenSize=$(xrandr | awk 'BEGIN {foundOutput=0}
   4     / '$output' / {foundOutput=1}
   5     /\*\+/ {print $1}
   6     /^[^ ]/ {if(foundOutput) exit 0}')
   7    if [ "$screenSize" != "" ]; then
   8      xrandr --output $output --fb $screenSize --off
   9      espeak -v es "Monitor apagado"
  10    else
  11      xrandr --output $output --auto
  12      espeak -v es "Monitor encendido"
  13    fi

Prevent Automatic Monitor Reactivation

After some time of inactivity or also when switching from the Linux console to an X session, the monitor will be activated again after a key press. To automatically switch off the monitor again, you could create a script. For this, open a text file with any text editor and insert the following: 

while [ 1 ]; do
  sudo vbetool dpms off
  sleep 20
done

Instead of sudo vbetool dpms off, any of the commands from the described variants can be used.
Afterwards, save the file and make it executable using

chmod u+x YOUR_SCRIPT_NAME

(with the actual file name) and run it in the background using

./YOUR_SCRIPT_NAME &

Sound effects On The GNOME Desktop

If you would like to have sound effects to help you navigating on the GNOME desktop, run 

sudo aptitude install freedesktop-sound-theme
gconftool-2 --type bool --set /desktop/gnome/sound/event_sounds true
eval $(dbus-launch); export DBUS_SESSION_BUS_ADDRESS DBUS_SESSION_BUS_PID
GSETTINGS_BACKEND=dconf gsettings set org.gnome.desktop.sound event-sounds true

faster speaking eSpeak

The eSpeak speech synthesis can speak faster by adding a configuration option to the appropriate voices file. Those voices files can be found under /usr/lib/i386-linux-gnu/espeak-data/voices/. Pick there your language file (e. g. en-us or de). Open the appropriate file as administrator in a text editor and insert the following line: 

speed 150

This will make eSpeak speak 50 % faster.

More Tips

More tips are available on https://web.archive.org/web/20220516221547/http://brl.thefreecat.org/wiki/