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e5afd5c38b
* Simplify nx config (no point separately caching es and js builds - they both need to be done for any code changes). Fix some no-op type definitions i.e. X extends any, and enforce templated property types as having to extend GeoJsonProperties throughout. * Upgrade typescript. Had to update topojson-* type defs to avoid the P = GeoJsonProperties problem in geojson-rbush. Also fix a couple of floating point precision related issues that eslint now apparently catches! * Retire tslint. * Upgrade eslint and prettier. Add minimal prettier config (defaults have changed) to avoid widespread, minor formatting changes (trailing commas mostly).
74 lines
2.1 KiB
TypeScript
74 lines
2.1 KiB
TypeScript
import { Feature, LineString, GeoJsonProperties } from "geojson";
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import { lineString } from "@turf/helpers";
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import { getGeom } from "@turf/invariant";
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import Spline from "./lib/spline";
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/**
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* Takes a {@link LineString|line} and returns a curved version
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* by applying a [Bezier spline](http://en.wikipedia.org/wiki/B%C3%A9zier_spline)
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* algorithm.
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*
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* The bezier spline implementation is by [Leszek Rybicki](http://leszek.rybicki.cc/).
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*
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* @name bezierSpline
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* @param {Feature<LineString>} line input LineString
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* @param {Object} [options={}] Optional parameters
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* @param {Object} [options.properties={}] Translate properties to output
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* @param {number} [options.resolution=10000] time in milliseconds between points
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* @param {number} [options.sharpness=0.85] a measure of how curvy the path should be between splines
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* @returns {Feature<LineString>} curved line
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* @example
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* var line = turf.lineString([
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* [-76.091308, 18.427501],
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* [-76.695556, 18.729501],
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* [-76.552734, 19.40443],
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* [-74.61914, 19.134789],
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* [-73.652343, 20.07657],
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* [-73.157958, 20.210656]
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* ]);
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*
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* var curved = turf.bezierSpline(line);
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*
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* //addToMap
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* var addToMap = [line, curved]
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* curved.properties = { stroke: '#0F0' };
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*/
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function bezier<P extends GeoJsonProperties = GeoJsonProperties>(
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line: Feature<LineString> | LineString,
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options: {
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properties?: P;
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resolution?: number;
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sharpness?: number;
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} = {}
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): Feature<LineString, P> {
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// Optional params
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const resolution = options.resolution || 10000;
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const sharpness = options.sharpness || 0.85;
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const coords: [number, number][] = [];
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const points = getGeom(line).coordinates.map((pt) => {
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return { x: pt[0], y: pt[1] };
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});
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const spline = new Spline({
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duration: resolution,
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points,
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sharpness,
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});
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const pushCoord = (time: number) => {
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var pos = spline.pos(time);
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if (Math.floor(time / 100) % 2 === 0) {
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coords.push([pos.x, pos.y]);
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}
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};
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for (var i = 0; i < spline.duration; i += 10) {
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pushCoord(i);
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}
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pushCoord(spline.duration);
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return lineString(coords, options.properties);
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}
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export default bezier;
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