dagre-rs

A complete Rust port of dagre.js -- hierarchical directed graph layout using the Sugiyama method.

Features

• Full 27-step layout pipeline matching dagre.js behavior
• All four rank directions: TB (top-to-bottom), BT, LR, RL
• Compound (nested) graph support with subgraph boundaries
• Edge label placement and self-loop routing
• Network simplex rank assignment
• Barycenter-based crossing minimization
• Brandes-Koepf coordinate assignment (4-direction sweep + median balance)
• Graph data structure with directed/undirected, multigraph, and compound modes
• Graph algorithms: topological sort, Dijkstra, Bellman-Ford, Floyd-Warshall, Tarjan SCC, Prim MST, and more
• JSON serialization via serde
• Zero runtime dependencies (only log and optional serde)

Compatibility

This crate tracks @dagrejs/dagre v3.0.1-pre (commit 4713b59). The reference data in cross-validate/reference_data.json is generated against this exact commit; see cross-validate/SETUP.md for how to reproduce.

Cross-validated against dagre.js on 20 reference graphs covering single nodes, chains, diamonds, cycles, fan-outs, disconnected components, edge labels, self-loops, compound subgraphs, all four rank directions, custom separators, margins, parallel edges, and varying node sizes. All produce identical coordinates, ranks, orders, and graph dimensions.

Downstream using dagre-d3-es or dagre.js v0.8.5 (mermaid, Go d2)

@dagrejs/dagre changed its NetworkSimplex tie-breaking behavior between v0.8.5 and the current 3.x line: when two crossing-reduction sweeps tie on crossing count, the new behavior keeps the last tied layering, while v0.8.5 (still used by dagre-d3-es and Go d2) keeps the first. Set LayoutOptions { tie_keep_first: true, .. } to opt into the v0.8.5 behavior — required for byte-identical layouts when interoperating with those downstreams.

Usage

use dagre::graph::{Graph, GraphOptions};
use dagre::{layout, LayoutOptions, NodeLabel, EdgeLabel};

// Create a directed graph
let mut g = Graph::with_options(GraphOptions {
    directed: true,
    multigraph: true,
    compound: true,
});

// Add nodes with dimensions
let mut a = NodeLabel::default();
a.width = 50.0;
a.height = 50.0;
g.set_node("a".into(), Some(a));

let mut b = NodeLabel::default();
b.width = 50.0;
b.height = 50.0;
g.set_node("b".into(), Some(b));

// Add an edge
g.set_edge("a", "b", Some(EdgeLabel::default()), None);

// Run layout
layout(&mut g, None);

// Read results
let node_a = g.node("a").unwrap();
println!("a: x={}, y={}", node_a.x.unwrap(), node_a.y.unwrap());

Configuration

use dagre::{LayoutOptions, RankDir, Ranker};

let opts = LayoutOptions {
    rankdir: RankDir::LR,     // left-to-right layout
    nodesep: 60.0,            // horizontal separation between nodes
    ranksep: 80.0,            // vertical separation between ranks
    edgesep: 20.0,            // separation between edges
    marginx: 10.0,            // horizontal margin
    marginy: 10.0,            // vertical margin
    ranker: Ranker::NetworkSimplex,
    ..Default::default()
};

layout(&mut g, Some(opts));

Project stats

CI runs cargo fmt --check, cargo clippy --all-targets --all-features -- -D warnings, and cargo test --all-features on every push and pull request — see .github/workflows/ci.yml.

License

Apache-2.0