CDT.js

A JavaScript library for Constrained Delaunay Triangulation powered by WebAssembly.

Installation

npm install cdt-js

Usage

ES Modules

import CDTModule, { Point, Edge } from 'cdt-js';

CDTModule().then((CDT) => {
  const triangulation = new CDT.Triangulation();
  const vertices: Point[] = [
    { x:   0, y:   0 },
    { x: 100, y:   0 },
    { x: 100, y: 100 },
    { x:   0, y: 100 },
    { x:  50, y:  50 }
  ];
  const edges: Edge[] = [
    { from: 0, to: 1 },
    { from: 1, to: 2 },
    { from: 2, to: 3 },
    { from: 3, to: 0 },
  ];
  triangulation.insertVertices(vertices);
  triangulation.insertEdges(edges);
  triangulation.eraseOuterTrianglesAndHoles();
  const vertices = triangulation.getVertices();
  const triangles = triangulation.getTriangles();
  const fixedEdges = triangulation.getFixedEdges();
  const extractedEdges = CDT.extractEdgesFromTriangles(triangles);
  console.log(vertices);
  console.log(triangles);
  console.log(fixedEdges);
  console.log(extractedEdges);
});

API

Triangulation

Main class for triangulation operations.

Constructor

new Triangulation(
  vertexInsertionOrder?: VertexInsertionOrder,
  intersectingConstraintEdges?: IntersectingConstraintEdges,
  minDistToConstraintEdge?: number
);

• vertexInsertionOrder: Strategy specifying order in which a range of vertices is inserted (default: Auto)
• intersectingConstraintEdges: Strategy for treating intersecting constraint edges (default: NotAllowed)
• minDistToConstraintEdge: Distance within which a point is considered to be lying on a constraint edge (default: 0)

Methods

• insertVertices(vertices): Add an array of points
• insertEdges(edges): Add an array of constraint edges
• triangulate(): Perform triangulation
• getVertices(): Get array of vertices
• getEdges(): Get array of edges
• getTriangles(): Get array of triangles as vertex indices

Enums

VertexInsertionOrder

• Auto: Automatic insertion order optimized for better performance (default)
• AsProvided: Insert vertices in same order they are provided

IntersectingConstraintEdges

• NotAllowed: Constraint edge intersections are not allowed (default)
• TryResolve: Attempt to resolve constraint edge intersections
• DontCheck: No checks, slightly faster but less safe, user must provide a valid input without intersecting constraints

Examples

See the examples folder for complete examples.

Development

Prerequisites

• Emscripten SDK
• Node.js and npm

Building

npm run build

License

MIT