# Eunoia
- **Package:** Eunoia
- **Language:** Julia
- **Version:** 1.0.1
- **License:** [View license]()
- **Authors:** Johan Larsson \ and contributors
- [Source repository]()
- [License]()
Area-proportional **Euler and Venn diagrams** for Julia.
Eunoia fits and draws diagrams in which the areas of overlapping shapes (circles, ellipses, squares, rectangles, or rotated rectangles) are made to match a set of input quantities as closely as possible. It is the Julia binding for [eunoia](), a Rust library, and a sister package to the R ([eulerr]()) and Python ([eunoia-py]()) bindings.
The fitting engine ships as a native library reached through a small C ABI; its binaries are delivered as a lazily-downloaded Julia artifact, so installing the package needs no Rust toolchain.
## Installation
Eunoia is registered in the General registry, so install it with the Julia package manager:
```julia
using Pkg
Pkg.add("Eunoia")
```
## Quick start
```julia
using Eunoia
# Euler diagram from exclusive areas
fit = euler(Dict("A" => 5, "B" => 3, "A&B" => 1.5))
# Canonical Venn diagram with ellipses
venn(["A", "B", "C"]; shape = "ellipse")
```
`euler` returns an `EulerFit` and `venn` a `VennFit`, both carrying the fitted shapes, original/fitted values, per-region residuals and `region_error`, the overall `loss`, and (for complement fits) a `container`. See the [API Reference]() for the full surface.
## Plotting
Rendering lives in a [Makie]() package extension that loads automatically once a backend is imported:
```julia
using Eunoia, CairoMakie
fit = euler(Dict("A" => 5, "B" => 3, "A&B" => 1.5))
eunoiaplot(fit; quantities = true, legend = true)
```
See the [gallery]() for a tour of the plotting options.
## Citation
If you use Eunoia.jl in your research, please cite the paper:
> Larsson, J., & Lee, N. M. (2026). *Eunoia: Area-Proportional Euler and Venn Diagrams in Rust, Julia, Python, R, and JavaScript* (arXiv:2611.02198). arXiv. [https://doi.org/10.48550/arXiv.2611.02198]()
```bibtex
@misc{larsson2026f,
title = {Eunoia: {{Area}}-Proportional {{Euler}} and {{Venn}} Diagrams in {{Rust}}, {{Julia}}, {{Python}}, {{R}}, and {{JavaScript}}},
shorttitle = {Eunoia},
author = {Larsson, Johan and Lee, Nicole M.},
year = {2026},
month = nov,
number = {arXiv:2611.02198},
eprint = {2611.02198},
primaryclass = {stat.CO},
publisher = {arXiv},
doi = {10.48550/arXiv.2611.02198},
archiveprefix = {arXiv}
}
```
BibLaTeX
```bibtex
@online{larsson2026f,
title = {Eunoia: {{Area}}-Proportional {{Euler}} and {{Venn}} Diagrams in {{Rust}}, {{Julia}}, {{Python}}, {{R}}, and {{JavaScript}}},
shorttitle = {Eunoia},
author = {Larsson, Johan and Lee, Nicole M.},
date = {2026-11-01},
eprint = {2611.02198},
eprinttype = {arXiv},
eprintclass = {stat.CO},
doi = {10.48550/arXiv.2611.02198},
pubstate = {prepublished}
}
```
[CITATION.cff]() contains the software metadata and preferred paper citation. The [Eunoia citation page](/docs/cite/) renders the paper in APA, BibTeX, BibLaTeX, and other formats.