268 lines
8.6 KiB
JavaScript
268 lines
8.6 KiB
JavaScript
import Check from "../Core/Check.js";
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import defined from "../Core/defined.js";
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import DeveloperError from "../Core/DeveloperError.js";
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import loadKTX2 from "../Core/loadKTX2.js";
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import Resource from "../Core/Resource.js";
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/**
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* @typedef {HTMLImageElement|HTMLCanvasElement|ImageBitmap} ImageryTypes
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*
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* The format in which {@link ImageryProvider} methods return an image may
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* vary by provider, configuration, or server settings. Most common are
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* <code>HTMLImageElement</code>, <code>HTMLCanvasElement</code>, or on supported
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* browsers, <code>ImageBitmap</code>.
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*
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* See the documentation for each ImageryProvider class for more information about how they return images.
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*/
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/**
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* Provides imagery to be displayed on the surface of an ellipsoid. This type describes an
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* interface and is not intended to be instantiated directly.
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*
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* @alias ImageryProvider
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* @constructor
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* @abstract
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*
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* @see ArcGisMapServerImageryProvider
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* @see BingMapsImageryProvider
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* @see OpenStreetMapImageryProvider
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* @see TileMapServiceImageryProvider
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* @see GoogleEarthEnterpriseImageryProvider
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* @see GoogleEarthEnterpriseMapsProvider
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* @see GridImageryProvider
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* @see IonImageryProvider
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* @see MapboxImageryProvider
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* @see MapboxStyleImageryProvider
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* @see SingleTileImageryProvider
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* @see TileCoordinatesImageryProvider
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* @see UrlTemplateImageryProvider
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* @see WebMapServiceImageryProvider
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* @see WebMapTileServiceImageryProvider
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*
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* @demo {@link https://sandcastle.cesium.com/index.html?src=Imagery%20Layers.html|Cesium Sandcastle Imagery Layers Demo}
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* @demo {@link https://sandcastle.cesium.com/index.html?src=Imagery%20Layers%20Manipulation.html|Cesium Sandcastle Imagery Manipulation Demo}
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*/
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function ImageryProvider() {
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DeveloperError.throwInstantiationError();
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}
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Object.defineProperties(ImageryProvider.prototype, {
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/**
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* Gets the rectangle, in radians, of the imagery provided by the instance.
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* @memberof ImageryProvider.prototype
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* @type {Rectangle}
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* @readonly
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*/
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rectangle: {
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get: DeveloperError.throwInstantiationError,
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},
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/**
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* Gets the width of each tile, in pixels.
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* @memberof ImageryProvider.prototype
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* @type {number}
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* @readonly
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*/
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tileWidth: {
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get: DeveloperError.throwInstantiationError,
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},
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/**
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* Gets the height of each tile, in pixels.
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* @memberof ImageryProvider.prototype
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* @type {number}
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* @readonly
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*/
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tileHeight: {
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get: DeveloperError.throwInstantiationError,
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},
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/**
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* Gets the maximum level-of-detail that can be requested.
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* @memberof ImageryProvider.prototype
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* @type {number|undefined}
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* @readonly
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*/
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maximumLevel: {
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get: DeveloperError.throwInstantiationError,
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},
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/**
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* Gets the minimum level-of-detail that can be requested. Generally,
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* a minimum level should only be used when the rectangle of the imagery is small
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* enough that the number of tiles at the minimum level is small. An imagery
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* provider with more than a few tiles at the minimum level will lead to
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* rendering problems.
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* @memberof ImageryProvider.prototype
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* @type {number}
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* @readonly
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*/
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minimumLevel: {
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get: DeveloperError.throwInstantiationError,
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},
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/**
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* Gets the tiling scheme used by the provider.
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* @memberof ImageryProvider.prototype
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* @type {TilingScheme}
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* @readonly
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*/
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tilingScheme: {
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get: DeveloperError.throwInstantiationError,
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},
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/**
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* Gets the tile discard policy. If not undefined, the discard policy is responsible
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* for filtering out "missing" tiles via its shouldDiscardImage function. If this function
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* returns undefined, no tiles are filtered.
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* @memberof ImageryProvider.prototype
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* @type {TileDiscardPolicy}
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* @readonly
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*/
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tileDiscardPolicy: {
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get: DeveloperError.throwInstantiationError,
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},
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/**
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* Gets an event that is raised when the imagery provider encounters an asynchronous error. By subscribing
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* to the event, you will be notified of the error and can potentially recover from it. Event listeners
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* are passed an instance of {@link TileProviderError}.
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* @memberof ImageryProvider.prototype
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* @type {Event}
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* @readonly
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*/
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errorEvent: {
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get: DeveloperError.throwInstantiationError,
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},
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/**
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* Gets the credit to display when this imagery provider is active. Typically this is used to credit
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* the source of the imagery.
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* @memberof ImageryProvider.prototype
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* @type {Credit}
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* @readonly
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*/
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credit: {
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get: DeveloperError.throwInstantiationError,
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},
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/**
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* Gets the proxy used by this provider.
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* @memberof ImageryProvider.prototype
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* @type {Proxy}
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* @readonly
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*/
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proxy: {
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get: DeveloperError.throwInstantiationError,
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},
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/**
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* Gets a value indicating whether or not the images provided by this imagery provider
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* include an alpha channel. If this property is false, an alpha channel, if present, will
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* be ignored. If this property is true, any images without an alpha channel will be treated
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* as if their alpha is 1.0 everywhere. When this property is false, memory usage
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* and texture upload time are reduced.
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* @memberof ImageryProvider.prototype
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* @type {boolean}
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* @readonly
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*/
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hasAlphaChannel: {
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get: DeveloperError.throwInstantiationError,
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},
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});
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/**
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* Gets the credits to be displayed when a given tile is displayed.
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*
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* @param {number} x The tile X coordinate.
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* @param {number} y The tile Y coordinate.
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* @param {number} level The tile level;
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* @returns {Credit[]} The credits to be displayed when the tile is displayed.
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*/
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ImageryProvider.prototype.getTileCredits = function (x, y, level) {
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DeveloperError.throwInstantiationError();
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};
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/**
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* Requests the image for a given tile.
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*
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* @param {number} x The tile X coordinate.
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* @param {number} y The tile Y coordinate.
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* @param {number} level The tile level.
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* @param {Request} [request] The request object. Intended for internal use only.
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* @returns {Promise<ImageryTypes>|undefined} Returns a promise for the image that will resolve when the image is available, or
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* undefined if there are too many active requests to the server, and the request should be retried later.
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*/
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ImageryProvider.prototype.requestImage = function (x, y, level, request) {
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DeveloperError.throwInstantiationError();
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};
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/**
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* Asynchronously determines what features, if any, are located at a given longitude and latitude within
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* a tile.
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* This function is optional, so it may not exist on all ImageryProviders.
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*
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* @function
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*
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* @param {number} x The tile X coordinate.
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* @param {number} y The tile Y coordinate.
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* @param {number} level The tile level.
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* @param {number} longitude The longitude at which to pick features.
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* @param {number} latitude The latitude at which to pick features.
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* @return {Promise<ImageryLayerFeatureInfo[]>|undefined} A promise for the picked features that will resolve when the asynchronous
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* picking completes. The resolved value is an array of {@link ImageryLayerFeatureInfo}
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* instances. The array may be empty if no features are found at the given location.
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* It may also be undefined if picking is not supported.
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*
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*/
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ImageryProvider.prototype.pickFeatures = function (
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x,
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y,
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level,
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longitude,
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latitude
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) {
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DeveloperError.throwInstantiationError();
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};
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const ktx2Regex = /\.ktx2$/i;
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/**
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* Loads an image from a given URL. If the server referenced by the URL already has
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* too many requests pending, this function will instead return undefined, indicating
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* that the request should be retried later.
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*
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* @param {ImageryProvider} imageryProvider The imagery provider for the URL.
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* @param {Resource|string} url The URL of the image.
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* @returns {Promise<ImageryTypes|CompressedTextureBuffer>|undefined} A promise for the image that will resolve when the image is available, or
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* undefined if there are too many active requests to the server, and the request should be retried later.
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*/
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ImageryProvider.loadImage = function (imageryProvider, url) {
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//>>includeStart('debug', pragmas.debug);
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Check.defined("url", url);
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//>>includeEnd('debug');
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const resource = Resource.createIfNeeded(url);
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if (ktx2Regex.test(resource.url)) {
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// Resolves with `CompressedTextureBuffer`
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return loadKTX2(resource);
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} else if (
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defined(imageryProvider) &&
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defined(imageryProvider.tileDiscardPolicy)
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) {
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// Resolves with `HTMLImageElement` or `ImageBitmap`
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return resource.fetchImage({
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preferBlob: true,
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preferImageBitmap: true,
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flipY: true,
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});
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}
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return resource.fetchImage({
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preferImageBitmap: true,
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flipY: true,
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});
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};
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export default ImageryProvider;
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