Source code

Revision control

Copy as Markdown

Other Tools

# Contributing to libjxl
## Contributing with bug reports
For security-related issues please see [](
We welcome suggestions, feature requests and bug reports. Before opening a new
issue please take a look if there is already an existing one in the following
## Contributing with patches and Pull Requests
We'd love to accept your contributions to the JPEG XL Project. Please read
through this section before sending a Pull Request.
### Contributor License Agreements
Our project is open source under the terms outlined in the [LICENSE](LICENSE)
and [PATENTS](PATENTS) files. Before we can accept your contributions, even for
small changes, there are just a few small guidelines you need to follow:
Please fill out either the individual or corporate Contributor License Agreement
(CLA) with Google. JPEG XL Project is an an effort by multiple individuals and
companies, including the initial contributors Cloudinary and Google, but Google
is the legal entity in charge of receiving these CLA and relicensing this
* If you are an individual writing original source code and you're sure you
own the intellectual property, then you'll need to sign an [individual
* If you work for a company that wants to allow you to contribute your work,
then you'll need to sign a [corporate
Follow either of the two links above to access the appropriate CLA and
instructions for how to sign and return it. Once we receive it, we'll be able
to accept your pull requests.
***NOTE***: Only original source code from you and other people that have signed
the CLA can be accepted into the main repository.
### License
Contributions are licensed under the project's [LICENSE](LICENSE). Each new
file must include the following header when possible, with comment style adapted
to the language as needed:
// Copyright (c) the JPEG XL Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
### Code Reviews
All submissions, including submissions by project members, require review. We
use GitHub pull requests for this purpose. Consult
information on using pull requests.
### Contribution philosophy
* Prefer small changes, even if they don't implement a complete feature. Small
changes are easier to review and can be submitted faster. Think about what's
the smallest unit you can send that makes sense to review and submit in
isolation. For example, new modules that are not yet used by the tools but
have their own unittests are ok. If you have unrelated changes that
you discovered while working on something else, please send them in a
different Pull Request. If your are refactoring code and changing
functionality try to send the refactor first without any change in
functionality. Reviewers may ask you to split a Pull Request and it is
easier to create a smaller change from the beginning.
* Describe your commits. Add a meaningful description to your commit message,
explain what you are changing if it is not trivially obvious, but more
importantly explain *why* you are making those changes. For example "Fix
build" is not a good commit message, describe what build and if it makes sense
why is this fixing it or why was it failing without this. It is very likely
that people far in the future without any context you have right now will be
looking at your commit trying to figure out why was the change introduced. If
related to an issue in this or another repository include a link to it.
* Code Style: We follow the [Google C++ Coding
[clang-format]( configuration
file is available to automatically format your code, you can invoke it with
the `./ lint` helper tool.
* Testing: Test your change and explain in the commit message *how* your
commit was tested. For example adding unittests or in some cases just testing
with the existing ones is enough. In any case, mention what testing was
performed so reviewers can evaluate whether that's enough testing. In many
cases, testing that the Continuous Integration workflow passes is enough.
* Make one commit per Pull Request / review, unless there's a good reason not
to. If you have multiple changes send multiple Pull Requests and each one can
have its own review.
* When addressing comments from reviewers prefer to squash or fixup your
edits and force-push your commit. When merging changes into the repository we
don't want to include the history of code review back and forth changes or
typos. Reviewers can click on the "force-pushed" automatic comment on a Pull
Request to see the changes between versions. We use "Rebase and merge" policy
to keep a linear git history which is easier to reason about.
* Your change must pass the build and test workflows. There's a `` script
to help building and testing these configurations. See [building and
testing](doc/ for more details.
### Contributing checklist.
* Sign the CLA (only needed once per user, see above).
* AUTHORS: You can add your name to the [AUTHORS](AUTHORS) file.
* Style guide. Check `./ lint`.
* Meaningful commit description: What and *why*, links to issues, testing
* Squashed multiple edits into a single commit.
* Upload your changes to your fork and [create a Pull
# Community Guidelines
This project follows [Google's Open Source Community