If you would like to contribute to its development, you can clone the repository from Github, install the package in 'editable' mode and modify the source code in place. We recommend creating a virtual environment, using [`virtualenv`](https://virtualenv.pypa.io) or Python 3 [`venv`](https://docs.python.org/3/library/venv.html) module.
Once installed you can use the `ttx` command to convert binary font files (`.otf`, `.ttf`, etc) to the TTX xml format, edit them, and convert them back to binary format.
The TTX application works can be used in two ways, depending on what platform you run it on:
* As a command line tool (Windows/DOS, Unix, MacOSX)
* By dropping files onto the application (Windows, MacOS)
TTX detects what kind of files it is fed: it will output a `.ttx` file when it sees a `.ttf` or `.otf`, and it will compile a `.ttf` or `.otf` when the input file is a `.ttx` file.
By default, the output file is created in the same folder as the input file, and will have the same name as the input file but with a different extension.
TTX will _never_ overwrite existing files, but if necessary will append a unique number to the output filename (before the extension) such as `Arial#1.ttf`
When using TTX from the command line there are a bunch of extra options, these are explained in the help text, as displayed when typing `ttx -h` at the command prompt.
These additional options include:
* specifying the folder where the output files are created
* specifying which tables to dump or which tables to exclude
* merging partial `.ttx` files with existing `.ttf` or `.otf` files
Note that when you run `tox` without arguments, the tests are executed for all the environments listed in tox.ini's `envlist`. In our case, this includes Python 2.7, 3.5 and 3.6, so for this to work the `python2.7`, `python3.5` and `python3.6` executables must be available in your `PATH`.
You can specify an alternative environment list via the `-e` option, or the `TOXENV` environment variable:
TTX/FontTools development is ongoing in an active community of developers, that includes professional developers employed at major software corporations and type foundries as well as hobbyists.
The best place for discussions about TTX from an end-user perspective as well as TTX/FontTools development is the <https://groups.google.com/d/forum/fonttools> mailing list.
The fontTools project was started by Just van Rossum in 1999, and was maintained as an open source project at <http://sourceforge.net/projects/fonttools/>.
In 2008, Paul Wise (pabs3) began helping Just with stability maintenance.
In 2013 Behdad Esfahbod began a friendly fork, thoroughly reviewing the codebase and making changes at <https://github.com/behdad/fonttools> to add new features and support for new font formats.