Files
openlayers/src/ol/Feature.js

314 lines
8.9 KiB
JavaScript

/**
* @module ol/Feature
*/
import {assert} from './asserts.js';
import {listen, unlisten, unlistenByKey} from './events.js';
import EventType from './events/EventType.js';
import {inherits} from './util.js';
import BaseObject, {getChangeEventType} from './Object.js';
import Geometry from './geom/Geometry.js';
import Style from './style/Style.js';
/**
* @classdesc
* A vector object for geographic features with a geometry and other
* attribute properties, similar to the features in vector file formats like
* GeoJSON.
*
* Features can be styled individually with `setStyle`; otherwise they use the
* style of their vector layer.
*
* Note that attribute properties are set as {@link module:ol/Object} properties on
* the feature object, so they are observable, and have get/set accessors.
*
* Typically, a feature has a single geometry property. You can set the
* geometry using the `setGeometry` method and get it with `getGeometry`.
* It is possible to store more than one geometry on a feature using attribute
* properties. By default, the geometry used for rendering is identified by
* the property name `geometry`. If you want to use another geometry property
* for rendering, use the `setGeometryName` method to change the attribute
* property associated with the geometry for the feature. For example:
*
* ```js
*
* import Feature from 'ol/Feature';
* import Polygon from 'ol/geom/Polygon';
* import Point from 'ol/geom/Point';
*
* var feature = new Feature({
* geometry: new Polygon(polyCoords),
* labelPoint: new Point(labelCoords),
* name: 'My Polygon'
* });
*
* // get the polygon geometry
* var poly = feature.getGeometry();
*
* // Render the feature as a point using the coordinates from labelPoint
* feature.setGeometryName('labelPoint');
*
* // get the point geometry
* var point = feature.getGeometry();
* ```
*
* @constructor
* @extends {module:ol/Object}
* @param {module:ol/geom/Geometry|Object.<string, *>=} opt_geometryOrProperties
* You may pass a Geometry object directly, or an object literal containing
* properties. If you pass an object literal, you may include a Geometry
* associated with a `geometry` key.
* @api
*/
const Feature = function(opt_geometryOrProperties) {
BaseObject.call(this);
/**
* @private
* @type {number|string|undefined}
*/
this.id_ = undefined;
/**
* @type {string}
* @private
*/
this.geometryName_ = 'geometry';
/**
* User provided style.
* @private
* @type {module:ol/style/Style|Array.<module:ol/style/Style>|module:ol/style/Style~StyleFunction}
*/
this.style_ = null;
/**
* @private
* @type {module:ol/style/Style~StyleFunction|undefined}
*/
this.styleFunction_ = undefined;
/**
* @private
* @type {?module:ol/events~EventsKey}
*/
this.geometryChangeKey_ = null;
listen(
this, getChangeEventType(this.geometryName_),
this.handleGeometryChanged_, this);
if (opt_geometryOrProperties !== undefined) {
if (opt_geometryOrProperties instanceof Geometry ||
!opt_geometryOrProperties) {
const geometry = opt_geometryOrProperties;
this.setGeometry(geometry);
} else {
/** @type {Object.<string, *>} */
const properties = opt_geometryOrProperties;
this.setProperties(properties);
}
}
};
inherits(Feature, BaseObject);
/**
* Clone this feature. If the original feature has a geometry it
* is also cloned. The feature id is not set in the clone.
* @return {module:ol/Feature} The clone.
* @api
*/
Feature.prototype.clone = function() {
const clone = new Feature(this.getProperties());
clone.setGeometryName(this.getGeometryName());
const geometry = this.getGeometry();
if (geometry) {
clone.setGeometry(geometry.clone());
}
const style = this.getStyle();
if (style) {
clone.setStyle(style);
}
return clone;
};
/**
* Get the feature's default geometry. A feature may have any number of named
* geometries. The "default" geometry (the one that is rendered by default) is
* set when calling {@link module:ol/Feature~Feature#setGeometry}.
* @return {module:ol/geom/Geometry|undefined} The default geometry for the feature.
* @api
* @observable
*/
Feature.prototype.getGeometry = function() {
return (
/** @type {module:ol/geom/Geometry|undefined} */ (this.get(this.geometryName_))
);
};
/**
* Get the feature identifier. This is a stable identifier for the feature and
* is either set when reading data from a remote source or set explicitly by
* calling {@link module:ol/Feature~Feature#setId}.
* @return {number|string|undefined} Id.
* @api
*/
Feature.prototype.getId = function() {
return this.id_;
};
/**
* Get the name of the feature's default geometry. By default, the default
* geometry is named `geometry`.
* @return {string} Get the property name associated with the default geometry
* for this feature.
* @api
*/
Feature.prototype.getGeometryName = function() {
return this.geometryName_;
};
/**
* Get the feature's style. Will return what was provided to the
* {@link module:ol/Feature~Feature#setStyle} method.
* @return {module:ol/style/Style|Array.<module:ol/style/Style>|module:ol/style/Style~StyleFunction} The feature style.
* @api
*/
Feature.prototype.getStyle = function() {
return this.style_;
};
/**
* Get the feature's style function.
* @return {module:ol/style/Style~StyleFunction|undefined} Return a function
* representing the current style of this feature.
* @api
*/
Feature.prototype.getStyleFunction = function() {
return this.styleFunction_;
};
/**
* @private
*/
Feature.prototype.handleGeometryChange_ = function() {
this.changed();
};
/**
* @private
*/
Feature.prototype.handleGeometryChanged_ = function() {
if (this.geometryChangeKey_) {
unlistenByKey(this.geometryChangeKey_);
this.geometryChangeKey_ = null;
}
const geometry = this.getGeometry();
if (geometry) {
this.geometryChangeKey_ = listen(geometry,
EventType.CHANGE, this.handleGeometryChange_, this);
}
this.changed();
};
/**
* Set the default geometry for the feature. This will update the property
* with the name returned by {@link module:ol/Feature~Feature#getGeometryName}.
* @param {module:ol/geom/Geometry|undefined} geometry The new geometry.
* @api
* @observable
*/
Feature.prototype.setGeometry = function(geometry) {
this.set(this.geometryName_, geometry);
};
/**
* Set the style for the feature. This can be a single style object, an array
* of styles, or a function that takes a resolution and returns an array of
* styles. If it is `null` the feature has no style (a `null` style).
* @param {module:ol/style/Style|Array.<module:ol/style/Style>|module:ol/style/Style~StyleFunction} style Style for this feature.
* @api
* @fires module:ol/events/Event~Event#event:change
*/
Feature.prototype.setStyle = function(style) {
this.style_ = style;
this.styleFunction_ = !style ? undefined : createStyleFunction(style);
this.changed();
};
/**
* Set the feature id. The feature id is considered stable and may be used when
* requesting features or comparing identifiers returned from a remote source.
* The feature id can be used with the
* {@link module:ol/source/Vector~VectorSource#getFeatureById} method.
* @param {number|string|undefined} id The feature id.
* @api
* @fires module:ol/events/Event~Event#event:change
*/
Feature.prototype.setId = function(id) {
this.id_ = id;
this.changed();
};
/**
* Set the property name to be used when getting the feature's default geometry.
* When calling {@link module:ol/Feature~Feature#getGeometry}, the value of the property with
* this name will be returned.
* @param {string} name The property name of the default geometry.
* @api
*/
Feature.prototype.setGeometryName = function(name) {
unlisten(
this, getChangeEventType(this.geometryName_),
this.handleGeometryChanged_, this);
this.geometryName_ = name;
listen(
this, getChangeEventType(this.geometryName_),
this.handleGeometryChanged_, this);
this.handleGeometryChanged_();
};
/**
* Convert the provided object into a feature style function. Functions passed
* through unchanged. Arrays of module:ol/style/Style or single style objects wrapped
* in a new feature style function.
* @param {module:ol/style/Style~StyleFunction|!Array.<module:ol/style/Style>|!module:ol/style/Style} obj
* A feature style function, a single style, or an array of styles.
* @return {module:ol/style/Style~StyleFunction} A style function.
*/
export function createStyleFunction(obj) {
if (typeof obj === 'function') {
return obj;
} else {
/**
* @type {Array.<module:ol/style/Style>}
*/
let styles;
if (Array.isArray(obj)) {
styles = obj;
} else {
assert(obj instanceof Style,
41); // Expected an `module:ol/style/Style~Style` or an array of `module:ol/style/Style~Style`
styles = [obj];
}
return function() {
return styles;
};
}
}
export default Feature;