Contributions are welcome, and they are greatly appreciated! Every little bit helps, and credit will always be given.

You can contribute in many ways:

Types of Contributions

Report Bugs

Report bugs at

If you are reporting a bug, please include:

  • Your operating system name and version.
  • Any details about your local setup that might be helpful in troubleshooting.
  • Detailed steps to reproduce the bug.

Fix Bugs

Look through the GitHub issues for bugs. Anything tagged with “bug” and “help wanted” is open to whoever wants to implement it.

Implement Features

Look through the GitHub issues for features. Anything tagged with “enhancement” and “help wanted” is open to whoever wants to implement it.

Write Documentation

pixell could always use more documentation, whether as part of the official pixell docs, in docstrings, or even on the web in blog posts, articles, and such.

Submit Feedback

The best way to send feedback is to file an issue at

If you are proposing a feature:

  • Explain in detail how it would work.
  • Keep the scope as narrow as possible, to make it easier to implement.
  • Remember that this is a volunteer-driven project, and that contributions are welcome :)

Get Started!

Ready to contribute? Here’s how to set up pixell for local development.

  1. Fork the pixell repo on GitHub.

  2. Clone your fork locally:

    $ git clone
  3. Install your local copy for development:

    $ cd pixell/
    $ python build_ext -i

and add the cloned directory to your Python path so that changes you make in any python file are immediately reflected. e.g., in your .bashrc file:

export PYTHONPATH=$PYTHONPATH:/path/to/cloned/pixell/directory
  1. Create a branch for local development:

    $ git checkout -b name-of-your-bugfix-or-feature

    Now you can make your changes locally.

  2. When you’re done making changes, check that your changes pass flake8 and the tests:

    $ flake8 pixell tests
    $ py.test

    To get flake8, just pip install it into your virtualenv.

  3. Commit your changes and push your branch to GitHub:

    $ git add .
    $ git commit -m "Your detailed description of your changes."
    $ git push origin name-of-your-bugfix-or-feature
  4. Submit a pull request through the GitHub website.

Pull Request Guidelines

Before you submit a pull request, check that it meets these guidelines:

  1. The pull request should include tests.
  2. If the pull request adds functionality, the docs should be updated. Put your new functionality into a function with a docstring, and add the feature to the list in README.rst.
  3. The pull request should work for Python 3.6, 3.7 and 3.8. Check and make sure that the tests pass for all supported Python versions.


Only maintainers, who have access to the master branch, are able to deploy the package. This is accomplished by associating a tag, of the form vX.y.z, to the relevant commit in the master branch. We use bumpversion for this, in a way that is compatible with versioneer. Before initiating the release, be sure to update HISTORY.rst with the differences since last version (not required while we’re still in 0.y.z) and commit the changes. Then run:

$ bumpversion patch # possible: major / minor / patch
$ git push
$ git push --tags

Github Actions will then deploy to PyPI if tests pass.

The role of versioneer is to automatically embed version information in the distributed source code or installed package, based on the github tags. The role of bumpversion (in our configuration) is to generate sequential version numbers and create github corresponding git tags. The bumpversion and versioneer configurations are in setup.cfg.