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node_modules/leaflet/src/geo/crs/CRS.js

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+
+import {Bounds} from '../../geometry/Bounds';
+import {LatLng} from '../LatLng';
+import {LatLngBounds} from '../LatLngBounds';
+import * as Util from '../../core/Util';
+
+/*
+ * @namespace CRS
+ * @crs L.CRS.Base
+ * Object that defines coordinate reference systems for projecting
+ * geographical points into pixel (screen) coordinates and back (and to
+ * coordinates in other units for [WMS](https://en.wikipedia.org/wiki/Web_Map_Service) services). See
+ * [spatial reference system](https://en.wikipedia.org/wiki/Spatial_reference_system).
+ *
+ * Leaflet defines the most usual CRSs by default. If you want to use a
+ * CRS not defined by default, take a look at the
+ * [Proj4Leaflet](https://github.com/kartena/Proj4Leaflet) plugin.
+ *
+ * Note that the CRS instances do not inherit from Leaflet's `Class` object,
+ * and can't be instantiated. Also, new classes can't inherit from them,
+ * and methods can't be added to them with the `include` function.
+ */
+
+export var CRS = {
+	// @method latLngToPoint(latlng: LatLng, zoom: Number): Point
+	// Projects geographical coordinates into pixel coordinates for a given zoom.
+	latLngToPoint: function (latlng, zoom) {
+		var projectedPoint = this.projection.project(latlng),
+		    scale = this.scale(zoom);
+
+		return this.transformation._transform(projectedPoint, scale);
+	},
+
+	// @method pointToLatLng(point: Point, zoom: Number): LatLng
+	// The inverse of `latLngToPoint`. Projects pixel coordinates on a given
+	// zoom into geographical coordinates.
+	pointToLatLng: function (point, zoom) {
+		var scale = this.scale(zoom),
+		    untransformedPoint = this.transformation.untransform(point, scale);
+
+		return this.projection.unproject(untransformedPoint);
+	},
+
+	// @method project(latlng: LatLng): Point
+	// Projects geographical coordinates into coordinates in units accepted for
+	// this CRS (e.g. meters for EPSG:3857, for passing it to WMS services).
+	project: function (latlng) {
+		return this.projection.project(latlng);
+	},
+
+	// @method unproject(point: Point): LatLng
+	// Given a projected coordinate returns the corresponding LatLng.
+	// The inverse of `project`.
+	unproject: function (point) {
+		return this.projection.unproject(point);
+	},
+
+	// @method scale(zoom: Number): Number
+	// Returns the scale used when transforming projected coordinates into
+	// pixel coordinates for a particular zoom. For example, it returns
+	// `256 * 2^zoom` for Mercator-based CRS.
+	scale: function (zoom) {
+		return 256 * Math.pow(2, zoom);
+	},
+
+	// @method zoom(scale: Number): Number
+	// Inverse of `scale()`, returns the zoom level corresponding to a scale
+	// factor of `scale`.
+	zoom: function (scale) {
+		return Math.log(scale / 256) / Math.LN2;
+	},
+
+	// @method getProjectedBounds(zoom: Number): Bounds
+	// Returns the projection's bounds scaled and transformed for the provided `zoom`.
+	getProjectedBounds: function (zoom) {
+		if (this.infinite) { return null; }
+
+		var b = this.projection.bounds,
+		    s = this.scale(zoom),
+		    min = this.transformation.transform(b.min, s),
+		    max = this.transformation.transform(b.max, s);
+
+		return new Bounds(min, max);
+	},
+
+	// @method distance(latlng1: LatLng, latlng2: LatLng): Number
+	// Returns the distance between two geographical coordinates.
+
+	// @property code: String
+	// Standard code name of the CRS passed into WMS services (e.g. `'EPSG:3857'`)
+	//
+	// @property wrapLng: Number[]
+	// An array of two numbers defining whether the longitude (horizontal) coordinate
+	// axis wraps around a given range and how. Defaults to `[-180, 180]` in most
+	// geographical CRSs. If `undefined`, the longitude axis does not wrap around.
+	//
+	// @property wrapLat: Number[]
+	// Like `wrapLng`, but for the latitude (vertical) axis.
+
+	// wrapLng: [min, max],
+	// wrapLat: [min, max],
+
+	// @property infinite: Boolean
+	// If true, the coordinate space will be unbounded (infinite in both axes)
+	infinite: false,
+
+	// @method wrapLatLng(latlng: LatLng): LatLng
+	// Returns a `LatLng` where lat and lng has been wrapped according to the
+	// CRS's `wrapLat` and `wrapLng` properties, if they are outside the CRS's bounds.
+	wrapLatLng: function (latlng) {
+		var lng = this.wrapLng ? Util.wrapNum(latlng.lng, this.wrapLng, true) : latlng.lng,
+		    lat = this.wrapLat ? Util.wrapNum(latlng.lat, this.wrapLat, true) : latlng.lat,
+		    alt = latlng.alt;
+
+		return new LatLng(lat, lng, alt);
+	},
+
+	// @method wrapLatLngBounds(bounds: LatLngBounds): LatLngBounds
+	// Returns a `LatLngBounds` with the same size as the given one, ensuring
+	// that its center is within the CRS's bounds.
+	// Only accepts actual `L.LatLngBounds` instances, not arrays.
+	wrapLatLngBounds: function (bounds) {
+		var center = bounds.getCenter(),
+		    newCenter = this.wrapLatLng(center),
+		    latShift = center.lat - newCenter.lat,
+		    lngShift = center.lng - newCenter.lng;
+
+		if (latShift === 0 && lngShift === 0) {
+			return bounds;
+		}
+
+		var sw = bounds.getSouthWest(),
+		    ne = bounds.getNorthEast(),
+		    newSw = new LatLng(sw.lat - latShift, sw.lng - lngShift),
+		    newNe = new LatLng(ne.lat - latShift, ne.lng - lngShift);
+
+		return new LatLngBounds(newSw, newNe);
+	}
+};