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329 lines
9.0 KiB
329 lines
9.0 KiB
/**
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* @module ol/source/Cluster
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*/
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import EventType from '../events/EventType.js';
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import Feature from '../Feature.js';
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import Point from '../geom/Point.js';
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import VectorSource from './Vector.js';
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import {add as addCoordinate, scale as scaleCoordinate} from '../coordinate.js';
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import {assert} from '../asserts.js';
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import {
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buffer,
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createEmpty,
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createOrUpdateFromCoordinate,
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getCenter,
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} from '../extent.js';
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import {getUid} from '../util.js';
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/**
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* @typedef {Object} Options
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* @property {import("./Source.js").AttributionLike} [attributions] Attributions.
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* @property {number} [distance=20] Distance in pixels within which features will
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* be clustered together.
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* @property {number} [minDistance=0] Minimum distance in pixels between clusters.
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* Will be capped at the configured distance.
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* By default no minimum distance is guaranteed. This config can be used to avoid
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* overlapping icons. As a tradoff, the cluster feature's position will no longer be
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* the center of all its features.
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* @property {function(Feature):Point} [geometryFunction]
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* Function that takes an {@link module:ol/Feature~Feature} as argument and returns an
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* {@link module:ol/geom/Point~Point} as cluster calculation point for the feature. When a
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* feature should not be considered for clustering, the function should return
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* `null`. The default, which works when the underlying source contains point
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* features only, is
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* ```js
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* function(feature) {
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* return feature.getGeometry();
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* }
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* ```
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* See {@link module:ol/geom/Polygon~Polygon#getInteriorPoint} for a way to get a cluster
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* calculation point for polygons.
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* @property {function(Point, Array<Feature>):Feature} [createCluster]
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* Function that takes the cluster's center {@link module:ol/geom/Point~Point} and an array
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* of {@link module:ol/Feature~Feature} included in this cluster. Must return a
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* {@link module:ol/Feature~Feature} that will be used to render. Default implementation is:
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* ```js
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* function(point, features) {
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* return new Feature({
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* geometry: point,
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* features: features
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* });
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* }
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* ```
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* @property {VectorSource} [source=null] Source.
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* @property {boolean} [wrapX=true] Whether to wrap the world horizontally.
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*/
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/**
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* @classdesc
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* Layer source to cluster vector data. Works out of the box with point
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* geometries. For other geometry types, or if not all geometries should be
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* considered for clustering, a custom `geometryFunction` can be defined.
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*
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* If the instance is disposed without also disposing the underlying
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* source `setSource(null)` has to be called to remove the listener reference
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* from the wrapped source.
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* @api
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*/
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class Cluster extends VectorSource {
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/**
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* @param {Options} options Cluster options.
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*/
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constructor(options) {
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super({
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attributions: options.attributions,
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wrapX: options.wrapX,
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});
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/**
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* @type {number|undefined}
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* @protected
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*/
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this.resolution = undefined;
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/**
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* @type {number}
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* @protected
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*/
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this.distance = options.distance !== undefined ? options.distance : 20;
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/**
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* @type {number}
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* @protected
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*/
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this.minDistance = options.minDistance || 0;
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/**
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* @type {number}
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* @protected
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*/
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this.interpolationRatio = 0;
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/**
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* @type {Array<Feature>}
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* @protected
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*/
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this.features = [];
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/**
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* @param {Feature} feature Feature.
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* @return {Point} Cluster calculation point.
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* @protected
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*/
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this.geometryFunction =
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options.geometryFunction ||
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function (feature) {
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const geometry = /** @type {Point} */ (feature.getGeometry());
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assert(geometry.getType() == 'Point', 10); // The default `geometryFunction` can only handle `Point` geometries
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return geometry;
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};
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/**
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* @type {function(Point, Array<Feature>):Feature}
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* @private
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*/
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this.createCustomCluster_ = options.createCluster;
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/**
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* @type {VectorSource|null}
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* @protected
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*/
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this.source = null;
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/**
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* @private
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*/
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this.boundRefresh_ = this.refresh.bind(this);
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this.updateDistance(this.distance, this.minDistance);
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this.setSource(options.source || null);
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}
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/**
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* Remove all features from the source.
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* @param {boolean} [fast] Skip dispatching of {@link module:ol/source/VectorEventType~VectorEventType#removefeature} events.
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* @api
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*/
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clear(fast) {
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this.features.length = 0;
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super.clear(fast);
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}
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/**
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* Get the distance in pixels between clusters.
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* @return {number} Distance.
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* @api
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*/
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getDistance() {
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return this.distance;
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}
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/**
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* Get a reference to the wrapped source.
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* @return {VectorSource|null} Source.
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* @api
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*/
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getSource() {
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return this.source;
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}
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/**
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* @param {import("../extent.js").Extent} extent Extent.
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* @param {number} resolution Resolution.
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* @param {import("../proj/Projection.js").default} projection Projection.
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*/
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loadFeatures(extent, resolution, projection) {
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this.source.loadFeatures(extent, resolution, projection);
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if (resolution !== this.resolution) {
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this.resolution = resolution;
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this.refresh();
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}
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}
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/**
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* Set the distance within which features will be clusterd together.
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* @param {number} distance The distance in pixels.
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* @api
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*/
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setDistance(distance) {
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this.updateDistance(distance, this.minDistance);
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}
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/**
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* Set the minimum distance between clusters. Will be capped at the
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* configured distance.
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* @param {number} minDistance The minimum distance in pixels.
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* @api
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*/
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setMinDistance(minDistance) {
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this.updateDistance(this.distance, minDistance);
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}
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/**
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* The configured minimum distance between clusters.
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* @return {number} The minimum distance in pixels.
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* @api
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*/
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getMinDistance() {
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return this.minDistance;
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}
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/**
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* Replace the wrapped source.
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* @param {VectorSource|null} source The new source for this instance.
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* @api
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*/
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setSource(source) {
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if (this.source) {
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this.source.removeEventListener(EventType.CHANGE, this.boundRefresh_);
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}
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this.source = source;
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if (source) {
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source.addEventListener(EventType.CHANGE, this.boundRefresh_);
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}
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this.refresh();
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}
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/**
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* Handle the source changing.
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*/
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refresh() {
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this.clear();
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this.cluster();
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this.addFeatures(this.features);
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}
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/**
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* Update the distances and refresh the source if necessary.
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* @param {number} distance The new distance.
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* @param {number} minDistance The new minimum distance.
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*/
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updateDistance(distance, minDistance) {
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const ratio =
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distance === 0 ? 0 : Math.min(minDistance, distance) / distance;
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const changed =
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distance !== this.distance || this.interpolationRatio !== ratio;
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this.distance = distance;
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this.minDistance = minDistance;
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this.interpolationRatio = ratio;
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if (changed) {
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this.refresh();
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}
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}
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/**
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* @protected
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*/
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cluster() {
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if (this.resolution === undefined || !this.source) {
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return;
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}
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const extent = createEmpty();
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const mapDistance = this.distance * this.resolution;
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const features = this.source.getFeatures();
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/** @type {Object<string, true>} */
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const clustered = {};
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for (let i = 0, ii = features.length; i < ii; i++) {
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const feature = features[i];
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if (!(getUid(feature) in clustered)) {
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const geometry = this.geometryFunction(feature);
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if (geometry) {
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const coordinates = geometry.getCoordinates();
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createOrUpdateFromCoordinate(coordinates, extent);
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buffer(extent, mapDistance, extent);
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const neighbors = this.source
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.getFeaturesInExtent(extent)
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.filter(function (neighbor) {
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const uid = getUid(neighbor);
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if (uid in clustered) {
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return false;
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}
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clustered[uid] = true;
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return true;
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});
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this.features.push(this.createCluster(neighbors, extent));
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}
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}
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}
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}
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/**
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* @param {Array<Feature>} features Features
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* @param {import("../extent.js").Extent} extent The searched extent for these features.
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* @return {Feature} The cluster feature.
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* @protected
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*/
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createCluster(features, extent) {
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const centroid = [0, 0];
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for (let i = features.length - 1; i >= 0; --i) {
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const geometry = this.geometryFunction(features[i]);
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if (geometry) {
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addCoordinate(centroid, geometry.getCoordinates());
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} else {
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features.splice(i, 1);
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}
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}
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scaleCoordinate(centroid, 1 / features.length);
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const searchCenter = getCenter(extent);
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const ratio = this.interpolationRatio;
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const geometry = new Point([
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centroid[0] * (1 - ratio) + searchCenter[0] * ratio,
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centroid[1] * (1 - ratio) + searchCenter[1] * ratio,
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]);
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if (this.createCustomCluster_) {
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return this.createCustomCluster_(geometry, features);
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} else {
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return new Feature({
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geometry,
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features,
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});
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}
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}
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}
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export default Cluster;
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