# Development documentation

## Install dependencies and run tests

```bash
npm ci
# Necessary to setup skia-canvas.
npm run allow-scipts
npm test
```

## Writing unit tests

### Tests that compare with OpenCV

[OpenCV](https://opencv.org/) is a popular image processing library for C++ and Python.
We use it as a reference for some of the functions implemented in ImageJS.

All images used for comparison with OpenCV are generated by the Python script [`test/img/opencv/generate.py`](./test/img/opencv/generate.py).

To add a new test reference file:

- Update [`generate.py`](./test/img/opencv/generate.py) with the OpenCV code that creates the file.
- Run `generate.py` (see following paragraph).
- Add the new filename to the [`TestImagePath`](./test/TestImagePath.ts) type (alphabetical order).

To run the generation script, use the following steps:

- Install Python 3.x
- Run `python3 -m venv .venv` to create a virtual environment for the project
- Activate the venv or run the local `pip` and `python` commands.
  - `source .venv/bin/activate` (UNIX)
  - `.venv/Scripts/Activate.ps1` (Windows)
- Run `pip install opencv-python`
- Run `python test/img/opencv/generate.py`