iTowns / itowns / 10635241580

import Source from 'Source/Source';

import URLBuilder from 'Provider/URLBuilder';

import Extent, { globalExtentTMS } from 'Core/Geographic/Extent';

import CRS from 'Core/Geographic/Crs';

const extent = new Extent(CRS.tms_4326, 0, 0, 0);

/**

 * @classdesc

 * An object defining the source of resources to get from a [TMS]{@link

 * https://wiki.osgeo.org/wiki/Tile_Map_Service_Specification} server. It

 * inherits from {@link Source}.

 *

 * @extends Source

 *

 * @property {boolean} isTMSSource - Used to checkout whether this source is a

 * TMSSource. Default is true. You should not change this, as it is used

 * internally for optimisation.

 * @property {boolean} isInverted - The isInverted property is to be set to the

 * correct value, true or false (default being false) if the computation of the

 * coordinates needs to be inverted to match the same scheme as OSM, Google Maps

 * or other system. See [this link]{@link

 * https://alastaira.wordpress.com/2011/07/06/converting-tms-tile-coordinates-to-googlebingosm-tile-coordinates/}

 * for more information.

 * @property {Object} tileMatrixSetLimits - it describes the available tile for this layer

 * @property {Object} extentSetlimits - these are the extents of the set of identical zoom tiles.

 * @property {Object} zoom - Object containing the minimum and maximum values of

 * the level, to zoom in the source.

 * @property {number} zoom.min - The minimum level of the source. Default value

 * is 0.

 * @property {number} zoom.max - The maximum level of the source. Default value

 * is 20.

 * @property {function} tileMatrixCallback - a method that create a TileMatrix

 * identifier from the zoom level. For example, if set to `(zoomLevel) => 'EPSG:4326:' + zoomLevel`,

 * the TileMatrix that will be fetched at zoom level 5 will be the one with identifier `EPSG:4326:5`.

 * By default, the method returns the input zoom level.

 *

 * @example <caption><b>Source from OpenStreetMap server :</b></caption>

 * // Create the source

 * const tmsSource = new itowns.TMSSource({

 *     format: 'image/png',

 *     url: 'http://osm.io/styles/${z}/${x}/${y}.png',

 *     attribution: {

 *         name: 'OpenStreetMap',

 *         url: 'http://www.openstreetmap.org/',

 *     },

 *     crs: 'EPSG:3857',

 * });

 *

 * // Create the layer

 * const colorLayer = new itowns.ColorLayer('OPENSM', {

 *     source: tmsSource,

 * });

 *

 * // Add the layer

 * view.addLayer(colorLayer);

 *

 * @example <caption><b>Source from Mapbox server :</b></caption>

 * // Create the source

 * const orthoSource = new itowns.TMSSource({

 *     url: 'https://api.mapbox.com/v4/mapbox.satellite/${z}/${x}/${y}.jpg?access_token=' + accessToken,

 *     crs: 'EPSG:3857',

 * };

 *

 * // Create the layer

 * const imageryLayer = new itowns.ColorLayer("Ortho", {

 *     source: orthoSource,

 * };

 *

 * // Add the layer to the view

 * view.addLayer(imageryLayer);

 */

class TMSSource extends Source {

    /**

     * @param {Object} source - An object that can contain all properties of a

     * TMSSource and {@link Source}. Only `url` is mandatory.

     *

     * @constructor

     */

    constructor(source) {

        source.format = source.format || 'image/png';

        super(source);

        this.isTMSSource = true;

        if (!source.extent) {

            // default to the global extent

            this.extent = globalExtentTMS.get(source.crs);

        }

        this.zoom = source.zoom;

        this.isInverted = source.isInverted || false;

        this.crs = CRS.formatToTms(source.crs);

        this.tileMatrixSetLimits = source.tileMatrixSetLimits;

        this.extentSetlimits = {};

        this.tileMatrixCallback = source.tileMatrixCallback || (zoomLevel => zoomLevel);

        if (!this.zoom) {

            if (this.tileMatrixSetLimits) {

                const arrayLimits = Object.keys(this.tileMatrixSetLimits);

                const size = arrayLimits.length;

                const maxZoom = Number(arrayLimits[size - 1]);

                const minZoom = maxZoom - size + 1;

                this.zoom = {

                    min: minZoom,

                    max: maxZoom,

                };

            } else {

                this.zoom = { min: 0, max: Infinity };

            }

        }

    }

    urlFromExtent(extent) {

        return URLBuilder.xyz(extent, this);

    }

    onLayerAdded(options) {

        super.onLayerAdded(options);

        // Build extents of the set of identical zoom tiles.

        const parent = options.out.parent;

        // The extents crs is chosen to facilitate in raster tile process.

        const crs = parent ? parent.extent.crs : options.out.crs;

        if (this.tileMatrixSetLimits && !this.extentSetlimits[crs]) {

            this.extentSetlimits[crs] = {};

            extent.crs = this.crs;

            for (let i = this.zoom.max; i >= this.zoom.min; i--) {

                const tmsl = this.tileMatrixSetLimits[i];

                const { west, north } = extent.set(i, tmsl.minTileRow, tmsl.minTileCol).as(crs);

                const { east, south } = extent.set(i, tmsl.maxTileRow, tmsl.maxTileCol).as(crs);

                this.extentSetlimits[crs][i] = new Extent(crs, west, east, south, north);

            }

        }

    }

    extentInsideLimit(extent, zoom) {

        // This layer provides data starting at level = layer.source.zoom.min

        // (the zoom.max property is used when building the url to make

        //  sure we don't use invalid levels)

        return zoom >= this.zoom.min && zoom <= this.zoom.max &&

                (this.extentSetlimits[extent.crs] == undefined || this.extentSetlimits[extent.crs][zoom].intersectsExtent(extent));

    }

}

export default TMSSource;