leaflet/src/layer/vector/Circle.js

JavaScript library for mobile-friendly interactive maps

/*
 * L.Circle is a circle overlay (with a certain radius in meters).
 */

L.Circle = L.Path.extend({
	initialize: function (latlng, radius, options) {
		L.Path.prototype.initialize.call(this, options);

		this._latlng = L.latLng(latlng);
		this._mRadius = radius;
	},

	options: {
		fill: true
	},

	setLatLng: function (latlng) {
		this._latlng = L.latLng(latlng);
		return this.redraw();
	},

	setRadius: function (radius) {
		this._mRadius = radius;
		return this.redraw();
	},

	projectLatlngs: function () {
		var lngRadius = this._getLngRadius(),
		    latlng = this._latlng,
		    pointLeft = this._map.latLngToLayerPoint([latlng.lat, latlng.lng - lngRadius]);

		this._point = this._map.latLngToLayerPoint(latlng);
		this._radius = Math.max(this._point.x - pointLeft.x, 1);
	},

	getBounds: function () {
		var lngRadius = this._getLngRadius(),
		    latRadius = (this._mRadius / 40075017) * 360,
		    latlng = this._latlng;

		return new L.LatLngBounds(
		        [latlng.lat - latRadius, latlng.lng - lngRadius],
		        [latlng.lat + latRadius, latlng.lng + lngRadius]);
	},

	getLatLng: function () {
		return this._latlng;
	},

	getPathString: function () {
		var p = this._point,
		    r = this._radius;

		if (this._checkIfEmpty()) {
			return '';
		}

		if (L.Browser.svg) {
			return 'M' + p.x + ',' + (p.y - r) +
			       'A' + r + ',' + r + ',0,1,1,' +
			       (p.x - 0.1) + ',' + (p.y - r) + ' z';
		} else {
			p._round();
			r = Math.round(r);
			return 'AL ' + p.x + ',' + p.y + ' ' + r + ',' + r + ' 0,' + (65535 * 360);
		}
	},

	getRadius: function () {
		return this._mRadius;
	},

	// TODO Earth hardcoded, move into projection code!

	_getLatRadius: function () {
		return (this._mRadius / 40075017) * 360;
	},

	_getLngRadius: function () {
		return this._getLatRadius() / Math.cos(L.LatLng.DEG_TO_RAD * this._latlng.lat);
	},

	_checkIfEmpty: function () {
		if (!this._map) {
			return false;
		}
		var vp = this._map._pathViewport,
		    r = this._radius,
		    p = this._point;

		return p.x - r > vp.max.x || p.y - r > vp.max.y ||
		       p.x + r < vp.min.x || p.y + r < vp.min.y;
	}
});

L.circle = function (latlng, radius, options) {
	return new L.Circle(latlng, radius, options);
};