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.github/CONTRIBUTING.md

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-We appreciate all contributions to improve MMRotate. Please refer to [CONTRIBUTING.md](https://github.com/open-mmlab/mmcv/blob/master/CONTRIBUTING.md) in MMCV for more details about the contributing guideline.
+# Contributing to MMRotate
+
+All kinds of contributions are welcome, including but not limited to the following.
+
+- Fixes (typo, bugs)
+- New features and components
+
+## Workflow
+
+1. Fork and pull the latest mmrotate
+1. Checkout a new branch with a meaningful name (do not use master branch for PRs)
+1. Commit your changes
+1. Create a PR
+
+```{note}
+- If you plan to add some new features that involve large changes, it is encouraged to open an issue for discussion first.
+- If you are the author of some papers and would like to include your method to mmrotate, please contact us. We will much appreciate your contribution.
+```
+
+## Code style
+
+### Python
+
+We adopt [PEP8](https://www.python.org/dev/peps/pep-0008/) as the preferred code style.
+
+We use the following tools for linting and formatting:
+
+- [flake8](http://flake8.pycqa.org/en/latest/): linter
+- [yapf](https://github.com/google/yapf): formatter
+- [isort](https://github.com/timothycrosley/isort): sort imports
+
+Style configurations of yapf and isort can be found in [setup.cfg](../setup.cfg).
+
+We use [pre-commit hook](https://pre-commit.com/) that checks and formats for `flake8`, `yapf`, `isort`, `trailing whitespaces`,
+fixes `end-of-files`, sorts `requirments.txt` automatically on every commit.
+The config for a pre-commit hook is stored in [.pre-commit-config](../.pre-commit-config.yaml).
+
+After you clone the repository, you will need to install initialize pre-commit hook.
+
+```
+pip install -U pre-commit
+```
+
+From the repository folder
+
+```
+pre-commit install
+```
+
+If you are facing an issue when installing markdown lint, you may install ruby for markdown lint by
+referring to [this repo](https://github.com/innerlee/setup) by following the usage and taking [`zzruby.sh`](https://github.com/innerlee/setup/blob/master/zzruby.sh)
+
+ or by the following steps
+
+ ```shell
+# install rvm
+curl -L https://get.rvm.io | bash -s -- --autolibs=read-fail
+rvm autolibs disable
+ # install ruby
+rvm install 2.7.1
+```
+
+After this on every commit check code linters and formatter will be enforced.
+
+> Before you create a PR, make sure that your code lints and is formatted by yapf.
+
+### C++ and CUDA
+
+We follow the [Google C++ Style Guide](https://google.github.io/styleguide/cppguide.html).