Offsets

Rings and paths are flat [x, y, z, ...] lists or a Float64Array. y is ignored.

offsetRingVariable

static offsetRingVariable(ring, distances, holes?: readonly OffsetHole[]): CurvedRegion2D[] Insets a closed ring by one distance per edge. Each hole grows by its own distances. Inside corners are exact arcs. An outer ring that crosses itself, such as a bowtie, throws InvalidTopology.

offsetCurvedRingVariable

static offsetCurvedRingVariable(region: CurvedRegion2D, distances, holeDistances?: (number[] | Float64Array)[]): CurvedRegion2D[]

Insets one region of lines and arcs by one distance per edge, with one list per hole ring.

Each distance is finite and not negative. A distance of 0 keeps its edge.
An arc stays on its centre: a convex arc moves to r − d, a concave arc or a hole’s arc to r + d.
A distance larger than an arc’s radius, a wrong count, or a negative or non-finite distance throws InvalidParameter.
A collapsed result is an empty list.

offsetPolylineRegions

static offsetPolylineRegions(path, width: number, closed: boolean, miterLimit?: number): CurvedRegion2D[] Strokes a path into regions of the given width. Corners are mitred up to miterLimit, default 4, and bevelled past it. A width that is not finite throws InvalidParameter.

offsetPolyline

static offsetPolyline(path, distance: number, options?: OffsetPolylineOptions): OffsetPath2D Offsets a path to one side.

import { OpenGeometry, type OffsetPath2D, type OffsetPolylineOptions } from 'opengeometry';

await OpenGeometry.create(
  { wasmURL: '/opengeometry_bg.wasm' },
  { workerURL: '/tessellation-worker.js' },
);

const options: OffsetPolylineOptions = { acuteThresholdDegrees: 35, bevel: true };
const kerb: OffsetPath2D = OpenGeometry.offsetPolyline([0, 0, 0, 10, 0, 0, 10, 0, 6], 0.5, options);
console.log(kerb.edges.length, kerb.bevelled, kerb.closed);

Types

OffsetHole

{ ring: number[] | Float64Array; distances: number[] | Float64Array }

OffsetPolylineOptions

Field	Default	Meaning
`acuteThresholdDegrees`	`35`	Corners sharper than this are bevelled
`bevel`	`true`	Bevel acute corners
`closed`	`true` when the ends meet	Treat the path as closed

OffsetPath2D

Field	Type	Meaning
`edges`	`CurvedRegionEdge[]`	The offset edges
`bevelled`	`number[]`	The indices of the bevelled corners
`closed`	`boolean`	Whether the result is closed

See Regions and offsets.

API Reference

Runtime

Bodies

History

Export

2D

Errors and constants

offsetRingVariable

offsetCurvedRingVariable

offsetPolylineRegions

offsetPolyline

Types

OffsetHole

OffsetPolylineOptions

OffsetPath2D

​offsetRingVariable

​offsetCurvedRingVariable

​offsetPolylineRegions

​offsetPolyline

​Types

​OffsetHole

​OffsetPolylineOptions

​OffsetPath2D

offsetRingVariable

offsetCurvedRingVariable

offsetPolylineRegions

offsetPolyline

Types

OffsetHole

OffsetPolylineOptions

OffsetPath2D