prismatoid 0.9.0

The Platform-Agnostic Reader Interface for Speech and Messages

PRISM

Prism is the Platform-agnostic Reader Interface for Speech and Messages. Since that's a hell of a mouthful, we just call it Prism for short. The name comes from prisms in optics, which are transparent optical components with flat surfaces that refract light into many beams. Thus, the metaphor: refract your TTS strings to send them to many different backends, potentially simultaneously.

Prism aims to unify the various screen reader abstraction libraries like SpeechCore, UniversalSpeech, SRAL, Tolk, etc., into a single unified system with a single unified API. Of course, we also support traditional TTS engines. I have tried to develop Prism in such a way that compilation is trivial and requires no external dependencies. To that end, the CMake builder will download all needed dependencies. However, since it uses cpm.cmake, vendoring of dependencies is very possible.

Building

To build Prism, all you need do is create a build directory and run cmake as you ordinarily would. The following build options are available:

Option	Description
PRISM_ENABLE_TESTS	Build the test suite (currently reserved).
PRISM_ENABLE_DEMOS	Enable building of demo apps to demonstrate Prism either generally or being used in a specific language.
PRISM_ENABLE_LINTING	Enable linting of source code with clang-tidy and other static analysis tools.
PRISM_ENABLE_VCPKG_SPECIFIC_OPTIONS	DO NOT USE. Enables options primarily used by the vcpkg package manager.

Prism is also in vcpkg. To install it:

vcpkg install ethindp-prism

The following features are available:

Feature	Description
speech-dispatcher	Enables linking to speech dispatcher and, by extension, enables the respective back-end module. If not defined, speech dispatcher will NOT be a supported backend.
orca	Enables use of glib and gdbus to communicate directly with the Orca screen reader. If not defined, Orca will NOT be available as a supported backend.

Documentation

Documentation uses mdbook. To view it offline, install mdbook and then run mdbook serve from the doc directory.

API

The API is fully documented in the documentation above. If the documentation and header do not align in guarantees or expectations, this is a bug and should be reported.

Bindings

Currently bindings are an in-progress effort. The following Bindings exist:

Language	Package/add-on/etc.
.NET	prismatoid
Python	Prismatoid

We welcome future bindings. If you write bindings and want them added here, please submit a PR!

License

This project is licensed under the Mozilla Public License version 2.0. Full details are available in the LICENSE file.

This project uses code from other projects. Specifically:

• The SAPI bridge is credited to the NVGT project, as well as the functions range_convert and range_convert_midpoint in utils.h and utils.cpp. Similar attribution goes to NVGT for the Android screen reader backend.
• The simdutf library is licensed under the Apache-2.0 license.
• On Windows, Prism includes NVDA controller client RPC definitions originally under LGPL-2.1 (and generated RPC stubs from those inputs). The Prism project has received permission to license the IDL files (and there generated outputs) under the MPL-2.0 regardless of the original license. Thus, you may assume that they are licensed under the MPL-2.0. The LGPL headers remain for providing attribution.

Contributing

Contributions are welcome. This includes, but is not limited to, documentation enhancements, new backends, bindings, build system improvements, etc. The project uses C++23 so please ensure that your compiler supports that standard.