# Tutorial for developing plugin with napari

Largely inspired from the [tutorial](https://napari.org/stable/plugins/first_plugin.html) on the official [napari] website

## Pre-requisites

1. Python
1. Environment manager ([conda], preferably __*not*__ Anaconda!!)
1. Some knowledge in Python
1. Some knowledge in [napari]

__Everything should be ran in a local environement to avoid breaking everything!__

## Setting-up the environment

### Creating and activating the environment

conda create -n napari-tuto -c conda-forge
conda activate napari-tuto

### Installing [napari]

conda install "napari[all]"

Once installed, you should be able to run the command `napari` from anywhere in a terminal and it should start [napari]

### Installing [cookiecutter]

conda install cookiecutter

Cookiecutter allows you to create the folders and file layout that will be the basis for your plugin.

### Setting up your first plugin layout

cookiecutter https://github.com/napari/cookiecutter-napari-plugin

It will ask few questions:

full_name [Napari Developer]: Leo
email [[e-mail]]: [e-mail]
github_username_or_organization [githubuser]: leo
plugin_name [napari-foobar]: napari-first
Select github_repository_url:
1 - https://github.com/leo/napari-first
2 - provide later
Choose from 1, 2 [1]: 2
module_name [napari_first]:
display_name [FooBar Segmentation]: My First Napari Plugin
short_description [A simple plugin to use FooBar segmentation within napari]: A simple first plugin
include_reader_plugin [y]: n
include_writer_plugin [y]: n
include_sample_data_plugin [y]: n
include_widget_plugin [y]:
use_git_tags_for_versioning [n]:
install_precommit [n]:

Using the previous parameters it will create a folder `napari-first` with the following layout:

napari-first
├── .github
│   └── workflows
│   └── test_and_deploy.yml
├── .gitignore
├── .napari-hub
│   ├── DESCRIPTION.md
│   └── config.yml
├── .pre-commit-config.yaml
├── LICENSE
├── MANIFEST.in
├── README.md
├── pyproject.toml
├── setup.cfg
├── src
│   └── napari_first
│   ├── __init__.py
│   ├── _tests
│   │   ├── __init__.py
│   │   └── test_widget.py
│   ├── _widget.py
│   └── napari.yaml
└── tox.ini

### Installing your plugin

Now, to install the plugin you can run the following command from the `napari-first` folder:

pip install -e .

Note the `-e` option for the `pip install` command it allows to install the plugin "in place" meaning that if you modify the code it will be directly integrated without having to re-install it.

Here is a small description of the files we will be looking at during this introduction:

| File name | Description |
|---|---|
|`README.md` | a file containing the instruction for your plugin|
|`setup.cfg` | the file that allows the installation of your plugin and its dependencies|
|`napari.yaml` | the file that tells [napari] where to find your plugin code and how to load it|
|`__init__.py` | the file that tells how to load the code|
|`_widget.py` | the file that contains the core of your plugin.|

If we have time we will look at the following files (likely in that order):
| File name | Description |
|---|---|
| `test_and_deploy.yml` | a file containing the information for testing when pushing on GitHub
| `_tests` | a folder containing the test files
|`pyproject.toml` | a file containing some parameters for your coding preferences|

[conda]: https://docs.conda.io/en/latest/
[napari]: https://napari.org/stable/
[cookiecutter]: https://github.com/cookiecutter/cookiecutter