ImageryProvider
查阅Mars3D API

abstract new Cesium.ImageryProvider()
engine/Source/Scene/ImageryProvider.js 45

Provides imagery to be displayed on the surface of an ellipsoid. This type describes an interface and is not intended to be instantiated directly.
Demo:
参考:

成员(属性)

readonly credit : Credit
engine/Source/Scene/ImageryProvider.js 145

Gets the credit to display when this imagery provider is active. Typically this is used to credit the source of the imagery.

readonly errorEvent : Event
engine/Source/Scene/ImageryProvider.js 134

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 TileProviderError.

readonly hasAlphaChannel : boolean
engine/Source/Scene/ImageryProvider.js 169

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.

readonly maximumLevel : number|undefined
engine/Source/Scene/ImageryProvider.js 86

Gets the maximum level-of-detail that can be requested.

readonly minimumLevel : number
engine/Source/Scene/ImageryProvider.js 100

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.

readonly proxy : Proxy
engine/Source/Scene/ImageryProvider.js 155

Gets the proxy used by this provider.

readonly rectangle : Rectangle
engine/Source/Scene/ImageryProvider.js 56

Gets the rectangle, in radians, of the imagery provided by the instance.

readonly tileDiscardPolicy : TileDiscardPolicy
engine/Source/Scene/ImageryProvider.js 122

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.

readonly tileHeight : number
engine/Source/Scene/ImageryProvider.js 76

Gets the height of each tile, in pixels.

readonly tileWidth : number
engine/Source/Scene/ImageryProvider.js 66

Gets the width of each tile, in pixels.

readonly tilingScheme : TilingScheme
engine/Source/Scene/ImageryProvider.js 110

Gets the tiling scheme used by the provider.

方法

static Cesium.ImageryProvider.loadImage(imageryProvider, url) → Promise.<(ImageryTypes|CompressedTextureBuffer)>|undefined
engine/Source/Scene/ImageryProvider.js 240

Loads an image from a given URL. If the server referenced by the URL already has too many requests pending, this function will instead return undefined, indicating that the request should be retried later.
参数名称 类型 描述信息
imageryProvider ImageryProvider The imagery provider for the URL.
url Resource | string The URL of the image.
返回值:
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.

getTileCredits(x, y, level) → Array.<Credit>
engine/Source/Scene/ImageryProvider.js 182

Gets the credits to be displayed when a given tile is displayed.
参数名称 类型 描述信息
x number The tile X coordinate.
y number The tile Y coordinate.
level number The tile level;
返回值:
The credits to be displayed when the tile is displayed.

pickFeatures(x, y, level, longitude, latitude) → Promise.<Array.<ImageryLayerFeatureInfo>>|undefined
engine/Source/Scene/ImageryProvider.js 218

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.
参数名称 类型 描述信息
x number The tile X coordinate.
y number The tile Y coordinate.
level number The tile level.
longitude number The longitude at which to pick features.
latitude number The latitude at which to pick features.
返回值:
A promise for the picked features that will resolve when the asynchronous picking completes. The resolved value is an array of 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.

requestImage(x, y, level, request) → Promise.<ImageryTypes>|undefined
engine/Source/Scene/ImageryProvider.js 196

Requests the image for a given tile.
参数名称 类型 描述信息
x number The tile X coordinate.
y number The tile Y coordinate.
level number The tile level.
request Request 可选 The request object. Intended for internal use only.
返回值:
Returns 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.
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