81 lines
3.0 KiB
Markdown
81 lines
3.0 KiB
Markdown
# Cthulhu
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## Introduction
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Cthulhu is a free, open source, flexible, and extensible screen reader
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that provides access to the graphical desktop via user-customizable
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combinations of speech and/or braille.
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Cthulhu works with applications and toolkits that support the assistive
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technology service provider interface (AT-SPI), which is the primary
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assistive technology infrastructure for the Solaris and Linux
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operating environments. Applications and toolkits supporting the
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AT-SPI include the GNOME GTK+ toolkit, the Java platform's Swing
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toolkit, OpenOffice/LibreOffice, Gecko, WebKitGtk, and KDE Qt toolkit.
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## Dependencies
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Cthulhu has the following dependencies:
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* Python 3 - Python platform
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* pygobject-3.0 - Python bindings for the GObject library
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* libpeas - GObject based Plugin engine
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* gtk+-3.0 - GTK+ toolkit
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* json-py - a JSON (<https://json.org/>) reader and writer in Python
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* python-speechd - Python bindings for Speech Dispatcher (optional)
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* BrlTTY - BrlTTY (<https://mielke.cc/brltty/>) support for braille (optional)
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* BrlAPI - BrlAPI support for braille (optional)
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* liblouis - Liblouis (<http://liblouis.org/>) support for contracted braille (optional)
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* py-setproctitle - Python library to set the process title (optional)
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* gstreamer-1.0 - GStreamer - Streaming media framework (optional)
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You are strongly encouraged to also have the latest stable versions
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of AT-SPI2 and ATK.
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## Braille
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Cthulhu depends upon the Python bindings for BrlAPI available in BrlTTY v4.5
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or better. You can determine if the Python bindings for BrlAPI are
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installed by running the following command:
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```sh
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python -c "import brlapi"
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```
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If you get an error, the Python bindings for BrlAPI are not installed.
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## Running Cthulhu
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If you wish to modify your Cthulhu preferences, you can press "Insert+space"
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while Cthulhu is running.
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To get help while running Cthulhu, press "Insert+H". This will enable
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"learn mode", which provides a spoken and brailled description of what
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various keyboard and braille input device actions will do. To exit
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learn mode, press "Escape." Finally, the preferences dialog contains
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a "Key Bindings" tab that lists the keyboard binding for Cthulhu.
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For more information, see the Cthulhu documentation which is available
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within Cthulhu.
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## Scripting Cthulhu
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So, you want to write a script for Cthulhu? The best thing to do is
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start by looking at other scripts under the src/cthulhu/scripts/ hierarchy
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of the source tree. Cthulhu also has an excellent plugin system, more documentation and examples coming soon.
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## Self-voicing
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Cthulhu offers a mechanism through which messages may be spoken directly by the screen reader. Usage is as follows:
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```bash
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# Speak hello world.
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echo "Hello world." | socat - UNIX-CLIENT:/tmp/cthulhu.sock
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# Speak Hello world without interrupting the previous speech.
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echo "<!#APPEND#!>Hello world." | socat - UNIX-CLIENT:/tmp/cthulhu.sock
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# Make hello world persistant in Braille.
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echo "Hello world.<#APPEND#>" | socat - UNIX-CLIENT:/tmp/cthulhu.sock
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```
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