vowl-wasm

An ontology visualisation engine in Rust, compiled to WebAssembly.

It turns an OWL ontology into something a browser can draw: parse the ontology, build a typed graph from it, settle that graph with a force-directed layout, and hand the result to JavaScript — either as structured data, or as a pointer into WASM linear memory that a rendering worker reads without copying.

Attribution

This is a clean-room Rust reimplementation of the VOWL visual notation defined by VisualDataWeb/WebVOWL (MIT, © 2014–2019 Vincent Link, Steffen Lohmann, Eduard Marbach, Stefan Negru, Vitalis Wiens). WebVOWL is the origin of the visual notation and of the ontology JSON shape this crate reads; none of its JavaScript, fixtures, or assets are vendored here. Both licence notices are carried in LICENSE.

This crate is not affiliated with or endorsed by the WebVOWL project or TIB.

Install

[dependencies]
vowl-wasm = "0.1"

From JavaScript, via the published bundle:

npm install @dreamlab-ai/vowl-wasm

Rust usage

use vowl_wasm::bindings::WebVowl;

let mut vowl = WebVowl::new();

vowl.load_ontology(r#"{
    "class": [
        { "id": "c1", "label": "Person",       "type": "owl:Class" },
        { "id": "c2", "label": "Organisation", "type": "owl:Class" }
    ],
    "property": [
        { "id": "p1", "label": "worksFor", "type": "owl:ObjectProperty",
          "domain": "c1", "range": "c2" }
    ]
}"#).expect("valid ontology");

vowl.init_simulation().expect("graph is loaded");
vowl.run_simulation(120).expect("graph is loaded");

assert_eq!(vowl.get_node_count(), 2);

JavaScript usage

import init, { WebVowl } from '@dreamlab-ai/vowl-wasm';

await init();

const vowl = new WebVowl();
vowl.loadOntology(ontologyJson);
vowl.initSimulation();
vowl.runSimulation(300);

console.log(vowl.getNodeCount(), vowl.getStatistics(), vowl.getMetadata());

For a rendering worker, NggExplorer avoids per-frame serialisation entirely:

import init, { NggExplorer } from '@dreamlab-ai/vowl-wasm';

const wasm = await init();
const explorer = new NggExplorer();
explorer.loadCsr(tierBytes);

// A zero-copy view over the live position buffer.
const positions = new Float32Array(
  wasm.memory.buffer, explorer.positionsPtr(), explorer.positionsLen()
);

while (!explorer.isFinished()) {
  explorer.tick();
  draw(positions); // no copy, no JSON
}

The view is invalidated by the next loadCsr and by any WASM memory growth — re-read positionsPtr() after either.

Public API

This is the frozen 0.1.0 surface. Names and signatures will not change without a major version bump.

WebVowl — always available

Filtering, folding and pinning are also always available: filterByDegree, filterHierarchy, toggleDatatypes, toggleSetOperators, resetVisibility, getNodeDegree, pinNode, unpinNode, isPinned, resetPins, getPinnedCount.

Feature-gated

Features

Every optional feature is off by default. The general-purpose engine — OWL/JSON parsing, the graph model, force layout (Barnes-Hut quadtree and the CSR simulation), OWL2 validation, pinning and statistics — is always compiled.

Each feature compiles standalone, and the combinations are checked in CI.

The published npm bundle is built with --features ngg1,markdown-ontology,interaction, because that is what the DreamLab corpus explorer needs. parallel, simd and debug-serde stay off in the published bundle; build from source to enable them.

Building

cargo test --all-features
cargo clippy --all-targets --all-features -- -D warnings

# The published bundle
wasm-pack build --target web --release --scope dreamlab-ai \
  --features ngg1,markdown-ontology,interaction

pkg/ is a build artefact and is not committed. CI uploads it as a workflow artifact, and tagged releases attach it as vowl-wasm-<version>-pkg.tgz.

MSRV: 1.85.

Migrating from webvowl-wasm / @dreamlab-ai/webvowl-wasm

This crate replaces three divergent in-tree copies of webvowl-wasm. Migrating:

1. Package name. webvowl-wasm → @dreamlab-ai/vowl-wasm. Replace any file: path dependency with a real semver pin.

2. Generated file names change, because the crate's lib name changed from webvowl_wasm to vowl_wasm:

   Before	After
   webvowl_wasm.js	vowl_wasm.js
   webvowl_wasm.d.ts	vowl_wasm.d.ts
   webvowl_wasm_bg.wasm	vowl_wasm_bg.wasm

   Anything that references those files by path — a bundler optimizeDeps entry, a hand-written init(url) call, a CDN URL, a CSP hash — needs updating. Importing the package by name is unaffected.

3. Version resets to 0.1.0. Neither of the old copies (1.0.0 and 0.3.4) described this API, so the numbering starts over. There is no implied compatibility with either.

4. Feature gates. NggExplorer, the markdown parser and checkNodeClick were unconditional before and are now behind ngg1, markdown-ontology and interaction. The published bundle enables all three, so a consumer of the npm package sees no change; a consumer building from source must ask for them.

5. Layout defaults changed. LayoutConfig::default() now carries general-purpose force constants rather than values tuned for one 1,155-node ontology. The old numbers are available as LayoutConfig::large_graph(). This affects WebVowl only — NggExplorer and CsrSimulation have their own parameters and are unchanged.

Licence

MIT. See LICENSE, which carries both this project's notice and the upstream WebVOWL notice.