Curve Interpolator

A lib for interpolating values over a cubic Cardinal/Catmull-Rom spline curve of n-dimenesions.

Installation

1npm install --save curve-interpolator

Basic usage

Reference the CurveInterpolator class:

1// commonjs
2const CurveInterpolator = require('curve-interpolator').CurveInterpolator;
3
4// es6
5import { CurveInterpolator } from 'curve-interpolator';
6

Define controlpoints you want the curve to pass through and pass it to the constructor of the CurveInterpolator to create an instance:

1const points = [
2  [0, 4],
3  [1, 2],
4  [3, 6.5],
5  [4, 8],
6  [5.5, 4],
7  [7, 3],
8  [8, 0],
9  ...
10];
11
12const interp = new CurveInterpolator(points, { tension: 0.2, alpha: 0.5 });
13
14// get single point
15const position = 0.3 // [0 - 1]
16const pt = interp.getPointAt(position)
17
18// get points evently distributed along the curve
19const segments = 1000;
20const pts = interp.getPoints(segments);
21
22// lookup values along x and y axises
23const axis = 1;
24const yintersects = interp.getIntersects(7, axis);
25
26/*
27max number of solutions (0 = all (default), 1 = first, -1 = last)
28A negative max value counts solutions from end of curve
29*/
30const axis = 0;
31const max = -1;
32const xintersects = interp.getIntersects(3.2, axis, max);
33
34// get bounding box
35const bbox = interp.getBoundingBox();

Online example on ObservableHQ:

• https://observablehq.com/@kjerandp/curve-interpolator-demo

Docs

Docs are generated using typedoc in ./docs. To create:

1npm run docs

Online: https://kjerandp.github.io/curve-interpolator/

License

MIT