LayerBaseVectorGeoJson.ts

/**
 * Created by gavorhes on 11/2/2015.
 */

import {LayerBaseVector, LayerBaseVectorOptions} from './LayerBaseVector';
import provide from '../util/provide';
import ol = require('custom-ol');
import $ = require('jquery');
import {MapMoveCls} from "../olHelpers/mapMoveCls";
import * as proj from '../olHelpers/projections';
import {proj3857} from "../olHelpers/projections";

let nm = provide('layers');

export interface crsTransform {
    dataProjection?: ol.proj.Projection;
    featureProjection?: ol.proj.Projection;
}


export interface LayerBaseVectorGeoJsonOptions extends LayerBaseVectorOptions {
    transform?: crsTransform;
    mapMoveObj?: MapMoveCls;
}

/**
 * The Vector GeoJson Layer
 * @augments LayerBaseVector
 */
export class LayerBaseVectorGeoJson extends LayerBaseVector {
    _geoJsonFormat: ol.format.GeoJSON;
    _transform: crsTransform;

    /**
     * @param {string|null} url - resource url, set to '' to make blank layer
     * @param {object} options - config
     * @param {string} [options.id] - layer id
     * @param {string} [options.name=Unnamed Layer] - layer name
     * @param {number} [options.opacity=1] - opacity
     * @param {boolean} [options.visible=true] - default visible
     * @param {number} [options.minZoom=undefined] - min zoom level, 0 - 28
     * @param {number} [options.maxZoom=undefined] - max zoom level, 0 - 28
     * @param {object} [options.params={}] the get parameters to include to retrieve the layer
     * @param {number} [options.zIndex=0] the z index for the layer
     * @param {function} [options.loadCallback] function to call on load, context this is the layer object
     * @param {boolean} [options.legendCollapse=false] if the legend item should be initially collapsed
     * @param {boolean} [options.legendCheckbox=true] if the legend item should have a checkbox for visibility
     * @param {boolean} [options.legendContent] additional content to add to the legend
     *
     * @param {boolean} [options.autoLoad=false] if the layer should auto load if not visible
     * @param {object} [options.style=undefined] the layer style, use openlayers default style if not defined
     * @param {boolean} [options.onDemand=false] if the layer should be loaded by extent on map move
     * @param {number} [options.onDemandDelay=300] delay before the map move callback should be called
     *
     * @param {object} [options.transform={}] SR transform, set as false for no transform
     * @param {string} options.transform.dataProjection=EPSG:4326 the data CRS
     * @param {string} options.transform.featureProjection=EPSG:3857 the feature/map CRS
     * @param {mapMoveMakeGetParams} [options.mapMoveMakeGetParams=function(lyr, extent, zoomLevel){}] function to create additional map move params
     * @param {MapMoveCls} [options.mapMoveObj=mapMove] alternate map move object for use with multi map pages
     */
    constructor(url?: string, options: LayerBaseVectorGeoJsonOptions = {}) {
        url = typeof url == 'string' ? url : '';
        super(url, options);

        this._geoJsonFormat = new ol.format.GeoJSON();

        this._transform = options.transform || {};
        this._transform.dataProjection = this._transform.dataProjection || proj.proj4326;
        this._transform.featureProjection = this._transform.featureProjection || proj3857;

        if (this.autoLoad || this.visible) {
            this._load();
        }
    }

    /**
     * add feature collection
     * @param {object} featureCollection - as geojson object
     */
    addFeatures(featureCollection: any) {
        this.source.addFeatures(
            this._geoJsonFormat.readFeatures(featureCollection,
                {dataProjection: this._transform.dataProjection,
                    featureProjection: this._transform.featureProjection}
                )
        );
    }


    /**
     * trigger load features
     * @protected
     * @returns {boolean} if already loaded
     */
    _load() {

        if (super._load()) {
            return true;
        }

        $.get(this._url,
            this._params,
            (d) => {
                this.addFeatures(d);
                this.loadCallback(this);
            }, 'json').fail(
            function () {
                this._loaded = false;
            }
        );

        return false;
    }

    /**
     * callback function on map move
     * @param {object} d the json response
     * @override
     */
    mapMoveCallback(d: Object) {
        super.mapMoveCallback(d);
        this._source.addFeatures(this._geoJsonFormat.readFeatures(d,
            {featureProjection: this._transform.featureProjection, dataProjection: this._transform.dataProjection}));
    }
}

nm.LayerBaseVectorGeoJson = LayerBaseVectorGeoJson;
export default LayerBaseVectorGeoJson;