cesium/packages/engine/Source/Scene/IonImageryProvider.js

import Check from "../Core/Check.js";
import Frozen from "../Core/Frozen.js";
import defined from "../Core/defined.js";
import Event from "../Core/Event.js";
import IonResource from "../Core/IonResource.js";
import RuntimeError from "../Core/RuntimeError.js";
import ArcGisMapServerImageryProvider from "./ArcGisMapServerImageryProvider.js";
import BingMapsImageryProvider from "./BingMapsImageryProvider.js";
import TileMapServiceImageryProvider from "./TileMapServiceImageryProvider.js";
import GoogleEarthEnterpriseMapsProvider from "./GoogleEarthEnterpriseMapsProvider.js";
import MapboxImageryProvider from "./MapboxImageryProvider.js";
import SingleTileImageryProvider from "./SingleTileImageryProvider.js";
import UrlTemplateImageryProvider from "./UrlTemplateImageryProvider.js";
import WebMapServiceImageryProvider from "./WebMapServiceImageryProvider.js";
import WebMapTileServiceImageryProvider from "./WebMapTileServiceImageryProvider.js";
import Google2DImageryProvider from "./Google2DImageryProvider.js";
import Azure2DImageryProvider from "./Azure2DImageryProvider.js";

// These values are the list of supported external imagery
// assets in the Cesium ion beta. They are subject to change.
const ImageryProviderAsyncMapping = {
  ARCGIS_MAPSERVER: ArcGisMapServerImageryProvider.fromUrl,
  BING: async (url, options) => {
    return BingMapsImageryProvider.fromUrl(url, options);
  },
  GOOGLE_EARTH: async (url, options) => {
    const channel = options.channel;
    delete options.channel;
    return GoogleEarthEnterpriseMapsProvider.fromUrl(url, channel, options);
  },
  MAPBOX: (url, options) => {
    return new MapboxImageryProvider({
      url: url,
      ...options,
    });
  },
  SINGLE_TILE: SingleTileImageryProvider.fromUrl,
  TMS: TileMapServiceImageryProvider.fromUrl,
  URL_TEMPLATE: (url, options) => {
    return new UrlTemplateImageryProvider({
      url: url,
      ...options,
    });
  },
  WMS: (url, options) => {
    return new WebMapServiceImageryProvider({
      url: url,
      ...options,
    });
  },
  WMTS: (url, options) => {
    return new WebMapTileServiceImageryProvider({
      url: url,
      ...options,
    });
  },
  GOOGLE_2D_MAPS: (ionResource, options) => {
    return new Google2DImageryProvider({
      ...options,
      url: ionResource,
    });
  },
  AZURE_MAPS: (ionResource, options) => {
    return new Azure2DImageryProvider({
      ...options,
      url: ionResource,
    });
  },
};

/**
 * @typedef {object} IonImageryProvider.ConstructorOptions
 *
 * Initialization options for the TileMapServiceImageryProvider constructor
 *
 * @property {string} [accessToken=Ion.defaultAccessToken] The access token to use.
 * @property {string|Resource} [server=Ion.defaultServer] The resource to the Cesium ion API server.
 */

/**
 * <div class="notice">
 * To construct a IonImageryProvider, call {@link IonImageryProvider.fromAssetId}. Do not call the constructor directly.
 * </div>
 *
 * Provides tiled imagery using the Cesium ion REST API.
 *
 * @alias IonImageryProvider
 * @constructor
 *
 * @param {IonImageryProvider.ConstructorOptions} [options] Object describing initialization options
 *
 * @example
 * const imageryLayer = Cesium.ImageryLayer.fromProviderAsync(Cesium.IonImageryProvider.fromAssetId(3812));
 * viewer.imageryLayers.add(imageryLayer);
 *
 * @see IonImageryProvider.fromAssetId
 */
function IonImageryProvider(options) {
  options = options ?? Frozen.EMPTY_OBJECT;

  this._defaultAlpha = undefined;
  this._defaultNightAlpha = undefined;
  this._defaultDayAlpha = undefined;
  this._defaultBrightness = undefined;
  this._defaultContrast = undefined;
  this._defaultHue = undefined;
  this._defaultSaturation = undefined;
  this._defaultGamma = undefined;
  this._defaultMinificationFilter = undefined;
  this._defaultMagnificationFilter = undefined;

  this._tileCredits = undefined;
  this._errorEvent = new Event();
}

Object.defineProperties(IonImageryProvider.prototype, {
  /**
   * Gets the rectangle, in radians, of the imagery provided by the instance.
   * @memberof IonImageryProvider.prototype
   * @type {Rectangle}
   * @readonly
   */
  rectangle: {
    get: function () {
      return this._imageryProvider.rectangle;
    },
  },

  /**
   * Gets the width of each tile, in pixels.
   * @memberof IonImageryProvider.prototype
   * @type {number}
   * @readonly
   */
  tileWidth: {
    get: function () {
      return this._imageryProvider.tileWidth;
    },
  },

  /**
   * Gets the height of each tile, in pixels.
   * @memberof IonImageryProvider.prototype
   * @type {number}
   * @readonly
   */
  tileHeight: {
    get: function () {
      return this._imageryProvider.tileHeight;
    },
  },

  /**
   * Gets the maximum level-of-detail that can be requested.
   * @memberof IonImageryProvider.prototype
   * @type {number|undefined}
   * @readonly
   */
  maximumLevel: {
    get: function () {
      return this._imageryProvider.maximumLevel;
    },
  },

  /**
   * Gets the minimum level-of-detail that can be requested. Generally,
   * a minimum level should only be used when the rectangle of the imagery is small
   * enough that the number of tiles at the minimum level is small.  An imagery
   * provider with more than a few tiles at the minimum level will lead to
   * rendering problems.
   * @memberof IonImageryProvider.prototype
   * @type {number}
   * @readonly
   */
  minimumLevel: {
    get: function () {
      return this._imageryProvider.minimumLevel;
    },
  },

  /**
   * Gets the tiling scheme used by the provider.
   * @memberof IonImageryProvider.prototype
   * @type {TilingScheme}
   * @readonly
   */
  tilingScheme: {
    get: function () {
      return this._imageryProvider.tilingScheme;
    },
  },

  /**
   * Gets the tile discard policy.  If not undefined, the discard policy is responsible
   * for filtering out "missing" tiles via its shouldDiscardImage function.  If this function
   * returns undefined, no tiles are filtered.
   * @memberof IonImageryProvider.prototype
   * @type {TileDiscardPolicy}
   * @readonly
   */
  tileDiscardPolicy: {
    get: function () {
      return this._imageryProvider.tileDiscardPolicy;
    },
  },

  /**
   * Gets an event that is raised when the imagery provider encounters an asynchronous error.  By subscribing
   * to the event, you will be notified of the error and can potentially recover from it.  Event listeners
   * are passed an instance of {@link TileProviderError}.
   * @memberof IonImageryProvider.prototype
   * @type {Event}
   * @readonly
   */
  errorEvent: {
    get: function () {
      return this._errorEvent;
    },
  },

  /**
   * Gets the credit to display when this imagery provider is active.  Typically this is used to credit
   * the source of the imagery.
   * @memberof IonImageryProvider.prototype
   * @type {Credit}
   * @readonly
   */
  credit: {
    get: function () {
      return this._imageryProvider.credit;
    },
  },

  /**
   * Gets a value indicating whether or not the images provided by this imagery provider
   * include an alpha channel.  If this property is false, an alpha channel, if present, will
   * be ignored.  If this property is true, any images without an alpha channel will be treated
   * as if their alpha is 1.0 everywhere.  When this property is false, memory usage
   * and texture upload time are reduced.
   * @memberof IonImageryProvider.prototype
   * @type {boolean}
   * @readonly
   */
  hasAlphaChannel: {
    get: function () {
      return this._imageryProvider.hasAlphaChannel;
    },
  },

  /**
   * Gets the proxy used by this provider.
   * @memberof IonImageryProvider.prototype
   * @type {Proxy}
   * @readonly
   * @default undefined
   */
  proxy: {
    get: function () {
      return undefined;
    },
  },
});

/**
 * Creates a provider for tiled imagery using the Cesium ion REST API.
 *
 * @param {Number} assetId  An ion imagery asset ID.
 * @param {IonImageryProvider.ConstructorOptions} [options] Object describing initialization options.
 * @returns {Promise<IonImageryProvider>} A promise which resolves to the created IonImageryProvider.
 *
 * @example
 * const imageryLayer = Cesium.ImageryLayer.fromProviderAsync(Cesium.IonImageryProvider.fromAssetId(3812));
 * viewer.imageryLayers.add(imageryLayer);
 *
 * @exception {RuntimeError} Cesium ion assetId is not an imagery asset
 * @exception {RuntimeError} Unrecognized Cesium ion imagery type
 */
IonImageryProvider.fromAssetId = async function (assetId, options) {
  //>>includeStart('debug', pragmas.debug);
  Check.typeOf.number("assetId", assetId);
  //>>includeEnd('debug');

  options = options ?? Frozen.EMPTY_OBJECT;
  const endpointResource = IonResource._createEndpointResource(
    assetId,
    options,
  );

  // A simple cache to avoid making repeated requests to ion for endpoints we've
  // already retrieved. This exists mainly to support Bing caching to reduce
  // world imagery sessions, but provides a small boost of performance in general
  // if constantly reloading assets
  const cacheKey = assetId.toString() + options.accessToken + options.server;
  let promise = IonImageryProvider._endpointCache[cacheKey];
  if (!defined(promise)) {
    promise = endpointResource.fetchJson();
    IonImageryProvider._endpointCache[cacheKey] = promise;
  }

  const endpoint = await promise;
  if (endpoint.type !== "IMAGERY") {
    throw new RuntimeError(
      `Cesium ion asset ${assetId} is not an imagery asset.`,
    );
  }

  let imageryProvider;
  const externalType = endpoint.externalType;
  if (!defined(externalType)) {
    imageryProvider = await TileMapServiceImageryProvider.fromUrl(
      new IonResource(endpoint, endpointResource),
    );
  } else {
    const factory = ImageryProviderAsyncMapping[externalType];

    if (!defined(factory)) {
      throw new RuntimeError(
        `Unrecognized Cesium ion imagery type: ${externalType}`,
      );
    }
    // Make a copy before editing since this object reference is cached;
    const options = { ...endpoint.options };
    const url = options.url;
    delete options.url;
    if (["GOOGLE_2D_MAPS", "AZURE_MAPS"].includes(endpoint.externalType)) {
      imageryProvider = await factory(
        new IonResource(endpoint, endpointResource),
        options,
      );
    } else {
      imageryProvider = await factory(url, options);
    }
  }

  const provider = new IonImageryProvider(options);

  imageryProvider.errorEvent.addEventListener(function (tileProviderError) {
    //Propagate the errorEvent but set the provider to this instance instead
    //of the inner instance.
    tileProviderError.provider = provider;
    provider._errorEvent.raiseEvent(tileProviderError);
  });

  provider._tileCredits = IonResource.getCreditsFromEndpoint(
    endpoint,
    endpointResource,
  );

  provider._imageryProvider = imageryProvider;

  return provider;
};

/**
 * Gets the credits to be displayed when a given tile is displayed.
 * @function
 *
 * @param {number} x The tile X coordinate.
 * @param {number} y The tile Y coordinate.
 * @param {number} level The tile level;
 * @returns {Credit[]} The credits to be displayed when the tile is displayed.
 */
IonImageryProvider.prototype.getTileCredits = function (x, y, level) {
  const innerCredits = this._imageryProvider.getTileCredits(x, y, level);
  if (!defined(innerCredits)) {
    return this._tileCredits;
  }

  return this._tileCredits.concat(innerCredits);
};

/**
 * Requests the image for a given tile.
 * @function
 *
 * @param {number} x The tile X coordinate.
 * @param {number} y The tile Y coordinate.
 * @param {number} level The tile level.
 * @param {Request} [request] The request object. Intended for internal use only.
 * @returns {Promise<ImageryTypes>|undefined} A promise for the image that will resolve when the image is available, or
 *          undefined if there are too many active requests to the server, and the request should be retried later.
 */
IonImageryProvider.prototype.requestImage = function (x, y, level, request) {
  return this._imageryProvider.requestImage(x, y, level, request);
};

/**
 * Asynchronously determines what features, if any, are located at a given longitude and latitude within
 * a tile. This function is optional, so it may not exist on all ImageryProviders.
 *
 * @function
 *
 * @param {number} x The tile X coordinate.
 * @param {number} y The tile Y coordinate.
 * @param {number} level The tile level.
 * @param {number} longitude The longitude at which to pick features.
 * @param {number} latitude  The latitude at which to pick features.
 * @return {Promise<ImageryLayerFeatureInfo[]>|undefined} A promise for the picked features that will resolve when the asynchronous
 *                   picking completes.  The resolved value is an array of {@link ImageryLayerFeatureInfo}
 *                   instances.  The array may be empty if no features are found at the given location.
 *                   It may also be undefined if picking is not supported.
 */
IonImageryProvider.prototype.pickFeatures = function (
  x,
  y,
  level,
  longitude,
  latitude,
) {
  return this._imageryProvider.pickFeatures(x, y, level, longitude, latitude);
};

//exposed for testing
IonImageryProvider._endpointCache = {};
export default IonImageryProvider;