ᛞ hugin

Plotting for OCaml

Hugin creates publication-quality plots from Nx arrays using a declarative, pipeline-oriented API.

What Hugin Does

Hugin turns immutable plot specifications into rendered output. You build a specification from mark constructors (line, point, bar, hist), decorate it with title, xlabel, and axis controls via the |> pipeline, and render with render_png, render_svg, or show.

Internally, rendering proceeds in three stages: the user-facing spec is compiled to a prepared tree (histograms binned, data bounds computed, marks auto-colored), then resolved to device-pixel coordinates, then drawn by a backend. Data compilation happens once; layout resolution is cheap and repeatable at different sizes.

System Requirements

Hugin needs Cairo and SDL2 for rendering:

# macOS
brew install cairo sdl2

# Ubuntu/Debian
apt install libcairo2-dev libsdl2-dev

Quick Start

open Hugin

let () =
  let x = Nx.linspace Nx.float32 0. (2. *. Float.pi) 100 in
  let y = Nx.sin x in
  line ~x ~y () |> title "Sine wave" |> render_png "sine.png"

Two marks on shared axes:

open Hugin

let () =
  let x = Nx.linspace Nx.float32 0. (2. *. Float.pi) 100 in
  layers [
    line ~x ~y:(Nx.sin x) ~label:"sin" ();
    line ~x ~y:(Nx.cos x) ~label:"cos" ~line_style:`Dashed ();
  ]
  |> legend |> render_png "trig.png"

Next Steps