search

elfalem / Leaflet.curve

A Leaflet plugin for drawing Bézier curves and other complex shapes.
Other
218 stars 52 forks source link
bezier-curve complex-shapes curve leaflet

readme

Leaflet.curve

A Leaflet plugin for drawing Bézier curves and other complex shapes. (DEMO)

Usage

If using directly, include the plugin after Leaflet:

<script src="https://github.com/elfalem/Leaflet.curve/raw/gh-pages/leaflet.js"></script>
<script src="https://github.com/elfalem/Leaflet.curve/raw/gh-pages/leaflet.curve.js"></script>

(If rendering using canvas AND using animations, include tween.js as well.)

If using Node.js, install and import:

yarn add @elfalem/leaflet-curve
import L from 'leaflet'  // import { curve, Curve } from 'leaflet'; // for TypeScript
import '@elfalem/leaflet-curve'

Add a path that includes a Bézier curve and straight lines:

var path = L.curve(['M',[50.54136296522163,28.520507812500004],
                    'C',[52.214338608258224,28.564453125000004],
                        [48.45835188280866,33.57421875000001],
                        [50.680797145321655,33.83789062500001],
                    'V',[48.40003249610685],
                    'L',[47.45839225859763,31.201171875],
                        [48.40003249610685,28.564453125000004],'Z'],
                    {color:'red',fill:true}).addTo(map);

Notes

API

The first argument to L.curve() is an array of path data. This is composed of commands and coordinates. The commands are a subset of the SVG path specification.

Command Parameters Description
M [lat,lng]+ move to [lat,lng]
L [lat,lng]+ line to [lat,lng]
H [lng]+ horizontal line to [lng]
V [lat]+ vertical line to [lat]
C ([lat1,lng1],[lat2,lng2],[lat,lng])+ cubic Bézier curve to [lat,lng] with control points at [lat1,lng1] and [lat2,lng2]
S ([lat2,lng2],[lat,lng])+ cubic bézier curve to [lat,lng] with control points at reflection of second control point of previous curve [lat1,lng1] and [lat2,lng2]
Q ([lat1,lng1],[lat,lng])+ quadratic Bézier curve to [lat,lng] with control point at [lat1,lng1]
T ([lat,lng])+ quadratic Bézier curve to [lat,lng] with control point at reflection of control point of previous curve [lat1,lng1]
Z close path (line to M)

Note that only absolute commands (uppercase) are implemented. It's possible to approximate elliptical arcs (command 'A') with Bézier curves (the elliptical-arc branch implements this command if you're interested).

The L.Curve class extends L.Path so options, events, and methods inherited from L.Path are available. The following new option and methods are introduced by L.Curve.

Options

Option Type Default Description
animate Integer or animate options object undefined Animates the curve. It takes a parameter which is the same one provided to the options parameter of Element.animate() method. Note: Web Animations API support varies across browsers.

Methods

Method Returns Description
setPath(pathData[]) this Replaces the current path with the given array of commands and coordinates.
getPath() pathData[] Returns array of the commands and coordinates in the path.
setLatLngs(pathData[]) this Alias to method this.setPath(pathData[]) using the naming convention of L.Polyline and other Leaflet components.
getLatLngs() pathData[] Alias to method this.getPath() using the naming convention of L.Polyline and other Leaflet components.
trace(samplingDistance[]) latLng[] Returns array of points that lie on the curve at the given distances. Sampling distance is a decimal value between 0 and 1 inclusive and is applied to each segment (i.e. command) of the curve. See DEMO for example.

License

MIT

Contributions