Contributing

Introduction

Join LVGL's community and leave your footprint in the library!

There are a lot of ways to contribute to LVGL even if you are new to the library or even new to programming.

It might be scary to make the first step but you have nothing to be afraid of. A friendly and helpful community is waiting for you. Get to know like-minded people and make something great together.

So let's find which contribution option fits you the best and help you join the development of LVGL!

Ways to contribute

  • Spread the Word: Share your LVGL experience with friends or on social media to boost its visibility.

  • Star the LVGL `repository <https://github.com/lvgl/lvgl>`__ Give us a star on GitHub! It helps a lot to LVGL more appealing for newcomers.

  • Report a bug: Open a GitHub Issue if something is not working.

  • Join our `Forum <https://forum.lvgl.io/>`__: Meet fellow developers and discuss questions

  • Tell your ideas: If you miss something from LVGL we would love to hear about it in a GitHub Issue

  • Develop features: Develop a pitch! Learn more below.

Feature development workflow

Terminology

  • Shaping: Convert raw ideas into something that can be developed. It includes examining opportunities, finding similar feature requests, roughly planning how it shall be implemented, tested, and taught through docs and examples.

  • Pitch: A document that is the result of shaping.

Schedule

We are working in 8-week cycles, each cycle starting at the beginning of odd months (e.g, a cycle could be from March to April).

  • Weeks 1-2: Cool Down (A relaxed period to step back, plan, fix bugs, and make a release): - Close the previous development phase: Feature stop, bug fixes, release, discuss anything that can be improved. - Prepare for the next development phase: Ideas, shaping, pitch creation.

  • Weeks 3-8: Develop Work on the planned pitches.

Feature Development Issue

For each raw idea, there is a dedicated issue where it's being "shaped". Anyone can open an idea/feature request issue and anyone can help the shaping process with comments.

We area using GitHub Labels to show the state of the issue:

  • shaping: Still discussing how to approach it.

  • pitched: We have come to a conclusion and created a pitch.

  • request-change(<user-name>): Each core member has a dedicated label, and when they request a change, they add their label.

  • under development: It's being developed by someone (can be developed only if no change is requested by the end of the cool-down phase).

  • ready: The pitch is developed and merged into master.

  • stale: Inactive, can be warmed up.

  • rejected: Not interested in this feature for some reason.

Pitch Files

There is a pitches branch in the LVGL repository which contains the already finished and the planned pitch Markdown files.

See the Template Pitch file to see how a pitch looks like.

Workflow

  1. Someone opens a new issue with an idea.

  2. Others jump in to comment on it. Core members play an important role in really understanding the problem and possible solutions, and request changes if needed. This is the shaping phase.

  3. It might take any length of time to shape an idea, but finally, it will be either converted to a pitch (created by a core member or a community member) or will become stale and closed.

  4. Pitches are typically created during the cool-down phase. Once we have a pitch, the development of the pitch can be undertaken by anyone (original author of the idea, other community member, core member). If someone applies for the development of the pitch, he/she will be marked as Responsible in the issue.

  5. Create a new branch for the developed pitch and continuously merge there via PRs.

  6. A pitch is ready if tests, docs, and examples are added.

  7. Finally, a PR is created against the master branch, which needs to be approved by the core members.

  8. Anything merged to the master branch by the end of the Development phase will be part of the release. Anything not ready can be continued; however, if it takes too long, it should be reviewed and shaped again.

  9. If a pitch is not taken by anyone in the next cool-down phase, it will be closed as stale.

Pull request

Merging new code into the lvgl, documentation, blog, examples, and other repositories happen via Pull requests (PR for short). A PR is a notification like "Hey, I made some updates to your project. Here are the changes, you can add them if you want." To do this you need a copy (called fork) of the original project under your account, make some changes there, and notify the original repository about your updates. You can see what it looks like on GitHub for LVGL here: https://github.com/lvgl/lvgl/pulls.

To add your changes you can edit files online on GitHub and send a new Pull request from there (recommended for small changes) or add the updates in your favorite editor/IDE and use git to publish the changes (recommended for more complex updates).

From GitHub

  1. Navigate to the file you want to edit.

  2. Click the Edit button in the top right-hand corner.

  3. Add your changes to the file.

  4. Add a commit message on the bottom of the page.

  5. Click the Propose changes button.

From command line

The instructions describe the main lvgl repository but it works the same way for the other repositories.

  1. Fork the lvgl repository. To do this click the "Fork" button in the top right corner. It will "copy" the lvgl repository to your GitHub account (https://github.com/<YOUR_NAME>?tab=repositories)

  2. Clone your forked repository.

  3. Add your changes. You can create a feature branch from master for the updates: git checkout -b <the-new-feature-branch-name>

  4. Commit and push your changes to the forked lvgl repository.

  5. Create a PR on GitHub from the page of your lvgl repository (https://github.com/<YOUR_NAME>/lvgl) by clicking the "New pull request" button. Don't forget to select the branch where you added your changes.

  6. Set the base branch. It means where you want to merge your update. In the lvgl repo both the fixes and new features go to master branch.

  7. Describe what is in the update. An example code is welcome if applicable.

  8. If you need to make more changes, just update your forked lvgl repo with new commits. They will automatically appear in the PR.

Commit message format

The commit messages format is inspired by Angular Commit Format.

The following structure should be used:

<type>(<scope>): <subject>
<BLANK LINE>
<body>
<BLANK LINE>
<footer>

Possible <type>s:

  • fix bugfix in the source code.

  • feat new feature

  • arch architectural changes

  • perf changes that affect the performance

  • example anything related to examples (even fixes and new examples)

  • docs anything related to the documentation (even fixes, formatting, and new pages)

  • test anything related to tests (new and updated tests or CI actions)

  • chore any minor formatting or style changes that would make the changelog noisy

<scope> is the module, file, or sub-system that is affected by the commit. It's usually one word and can be chosen freely. For example img, layout, txt, anim. The scope can be omitted.

<subject> contains a short description of the change:

  • use the imperative, present tense: "change" not "changed" nor "changes"

  • don't capitalize the first letter

  • no dot (.) at the end

  • max 90 characters

<body> optional and can be used to describe the details of this change.

<footer> shall contain

  • the words "BREAKING CHANGE" if the changes break the API

  • reference to the GitHub issue or Pull Request if applicable.

Some examples:

  • fix(img): update size if a new source is set

  • fix(bar): fix memory leak The animations weren't deleted in the destructor.

    Fixes: #1234

  • feat: add span widget

    The span widget allows mixing different font sizes, colors and styles. It's similar to HTML <span>

  • docs(porting): fix typo

Developer Certification of Origin (DCO)

Overview

To ensure all licensing criteria are met for every repository of the LVGL project, we apply a process called DCO (Developer's Certificate of Origin).

The text of DCO can be read here: https://developercertificate.org/.

By contributing to any repositories of the LVGL project you agree that your contribution complies with the DCO.

If your contribution fulfills the requirements of the DCO no further action is needed. If you are unsure feel free to ask us in a comment.