Orca v48.alpha

[TOC]

Attention Application Developers

If you are an application developer trying to make your application work with Orca, please see the README for application developers.

Introduction

Orca is a free, open source, flexible, and extensible screen reader that provides access to the graphical desktop via user-customizable combinations of speech and/or braille.

Orca works with applications and toolkits that support the assistive technology service provider interface (AT-SPI), which is the primary assistive technology infrastructure for the Solaris and Linux operating environments. Applications and toolkits supporting the AT-SPI include the GNOME GTK+ toolkit, the Java platform's Swing toolkit, OpenOffice/LibreOffice, Gecko, and WebKitGtk. AT-SPI support for the KDE Qt toolkit is currently being pursued.

See also https://orca.gnome.org for detailed information on Orca, including how to run Orca, how to communicate with the Orca user community, and where to log bugs and feature requests.

Dependencies

Orca v48.x is supported on GNOME 48.x only. We highly suggest you use the latest releases of GNOME because they contain accessibility infrastructure and application bug fixes that help Orca work better.

Orca also has the following dependencies:

• meson - The build system used by Orca
• Python 3 - Python platform
• pygobject-3.0 - Python bindings for the GObject library
• gtk+-3.0 - GTK+ toolkit
• python-speechd - Python bindings for Speech Dispatcher (optional)
• BrlTTY - BrlTTY (https://mielke.cc/brltty/) support for braille (optional)
• BrlAPI - BrlAPI support for braille (optional)
• liblouis - Liblouis (https://liblouis.io/) support for contracted braille (optional)
• py-setproctitle - Python library to set the process title (optional)
• gstreamer-1.0 - GStreamer - Streaming media framework (optional)
• python3-psutil - Process and system utilities (optional)
• libwnck3 - Used for mouse review (optional)

You are strongly encouraged to also have the latest stable versions of AT-SPI2 and ATK for the GNOME 48.x release.

Note for Braille Users

Orca depends upon the Python bindings for BrlAPI available in BrlTTY v4.5 or better. You can determine if the Python bindings for BrlAPI are installed by running the following command:

python -c "import brlapi"

If you get an error, the Python bindings for BrlAPI are not installed.

Building and Installing Orca

If you want to build Orca in a directory called _build and install Orca using your distro's default location (e.g /usr/local):

meson setup _build
meson compile -C _build
meson install -C _build

The installer will prompt you for sudo permission if needed.

To specify an alternative install location, use -D prefix= during setup (e.g. meson setup -D prefix=$HOME/orca-test _build).

To rebuild, either remove the build directory you created before (e.g. _build) or add the --reconfigure flag to the end of your existing meson setup command.

To uninstall, cd into the build directory you created and use ninja uninstall, or sudo ninja uninstall if you had installed Orca with sudo permission. Note that this will not remove the bytecode files in __pycache__. See this meson issue.

Running Orca

If you wish to modify your Orca preferences, you can press "Insert+space" while Orca is running.

To get help while running Orca, press "Insert+H". This will enable "learn mode", which provides a spoken and brailled description of what various keyboard and braille input device actions will do. To exit learn mode, press "Escape." Finally, the preferences dialog contains a "Key Bindings" tab that lists the keyboard binding for Orca.

For more information, see the Orca documentation which is available within Orca as well as at https://gnome.pages.gitlab.gnome.org/orca/help.

Orca's Scripts and Features

Orca's scripts provide access to applications and toolkits by responding to accessible events. For instance, when focus changes in an application, that application will emit an accessible event, object:state-changed:focused, which is then handled by the script associated with the application or toolkit.

If you have an application or toolkit that is accessible, but poorly supported by Orca, writing a custom script for that application might be the correct solution. (The correct solution might instead be to fix a bug in Orca and/or the application.) To see examples of scripts, look in src/orca/scripts of the source tree.

Scripts can also import features, but the features themselves should not live inside the script. Some examples of features imported by scripts include:

• src/orca/system_information_presenter.py
• src/orca/flat_review_presenter.py
• src/orca/notification-presenter.py
• src/orca/object_navigator.py

Please note: Historically features were implemented directly inside the scripts. Moving features outside of scripts is still a work in progress. Thus if you're wondering why some features are inside src/orca/scripts/default.py and others are not, the answer is that we haven't yet gotten around to migrating the features outside of default.py.

Experimental Features

By default, Orca uses speech-dispatcher for its TTS support. In addition, there is basic support for Spiel which allows choosing voices from multiple synthesizers, currently including eSpeak and Piper.

To test Spiel, configure Orca to build from the latest source. Once compiled, meson devenv will be used to run Orca.

meson setup --force-fallback-for=spiel -Dspiel=true _build
meson compile -C _build
meson install -C _build

If you have existing build directory, don't forget to use --reconfigure. If you have problems after an update, you may need to re-build and re-install:

meson subprojects purge --confirm
meson setup --reconfigure --force-fallback-for=spiel -Dspiel=true _build 
meson compile --clean -C _build
meson install -C _build

# Ensure any old Spiel providers get restarted
flatpak kill ai.piper.Speech.Provider
flatpak kill org.espeak.Speech.Provider

Then install the Flatpak for one or more speech providers (i.e. piper or speak) by running the commands in the Spiel documentation

To switch from Speech Dispatcher to Spiel, use orca --replace --speech-system=spiel. Using this flag is highly recommended while Orca's Spiel support is experimental. If you would like to use Spiel by default, you can select it in Orca's Preferences dialog. To then switch back to Speech Dispatcher, use orca --replace --speech-system=speechdispatcherfactory.

# Enter the development environment
meson devenv -C _build

# Run Orca
orca --replace --speech-system=spiel

# Exit the development environment
exit

Building Spiel from Source

For advanced users, Spiel and providers may be built from source. If you are unsure, consider using the available Flatpaks and consult the documentation for your distribution before proceeding.

1. Build and install Orca with Spiel

   Be sure to build Orca as described above, so the correct libspeechprovider version is available when building a provider in the next step. If you previously built Orca, follow the steps to update and re-build before continuing.

2. Next build and install a provider

   # Clone the repository, then select a provider in the "providers/" directory
   git clone https://github.com/eeejay/spiel-demos.git
   cd spiel-demos/providers/espeak
   
   # Build and install
   meson setup _build
   meson compile -C _build
   meson install -C _build

Now start Orca following the instructions above and the Spiel providers you installed will start automatically.