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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](http://en.wikipedia.org/wiki/Coordinate_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 Leafet'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);
}
};
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