ImageryProvider

Members

credit :Credit

Gets the credit to display when this imagery provider is active. Typically this is used to credit the source of the imagery. This function should not be called before ImageryProvider#ready returns true.

defaultAlpha :Number

The default alpha blending value of this provider, usually from 0.0 to 1.0. This can either be a simple number or a function with the signature function(frameState, layer, x, y, level). The function is passed the current FrameState, the layer, and the x, y, and level coordinates of the imagery tile for which the alpha is required, and it is expected to return the alpha value to use for the tile. The function is executed for every frame and for every tile, so it must be fast.

Default Value:

• undefined

defaultBrightness :Number

The default brightness of this provider. 1.0 uses the unmodified imagery color. Less than 1.0 makes the imagery darker while greater than 1.0 makes it brighter. This can either be a simple number or a function with the signature function(frameState, layer, x, y, level). The function is passed the current FrameState, the layer, and the x, y, and level coordinates of the imagery tile for which the brightness is required, and it is expected to return the brightness value to use for the tile. The function is executed for every frame and for every tile, so it must be fast.

Default Value:

• undefined

defaultContrast :Number

The default contrast of this provider. 1.0 uses the unmodified imagery color. Less than 1.0 reduces the contrast while greater than 1.0 increases it. This can either be a simple number or a function with the signature function(frameState, layer, x, y, level). The function is passed the current FrameState, the layer, and the x, y, and level coordinates of the imagery tile for which the contrast is required, and it is expected to return the contrast value to use for the tile. The function is executed for every frame and for every tile, so it must be fast.

Default Value:

• undefined

defaultGamma :Number

The default gamma correction to apply to this provider. 1.0 uses the unmodified imagery color. This can either be a simple number or a function with the signature function(frameState, layer, x, y, level). The function is passed the current FrameState, the layer, and the x, y, and level coordinates of the imagery tile for which the gamma is required, and it is expected to return the gamma value to use for the tile. The function is executed for every frame and for every tile, so it must be fast.

Default Value:

• undefined

defaultHue :Number

The default hue of this provider in radians. 0.0 uses the unmodified imagery color. This can either be a simple number or a function with the signature function(frameState, layer, x, y, level). The function is passed the current FrameState, the layer, and the x, y, and level coordinates of the imagery tile for which the hue is required, and it is expected to return the hue value to use for the tile. The function is executed for every frame and for every tile, so it must be fast.

Default Value:

• undefined

defaultSaturation :Number

The default saturation of this provider. 1.0 uses the unmodified imagery color. Less than 1.0 reduces the saturation while greater than 1.0 increases it. This can either be a simple number or a function with the signature function(frameState, layer, x, y, level). The function is passed the current FrameState, the layer, and the x, y, and level coordinates of the imagery tile for which the saturation is required, and it is expected to return the saturation value to use for the tile. The function is executed for every frame and for every tile, so it must be fast.

Default Value:

• undefined

errorEvent :Event

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.

extent :Extent

Gets the extent, in radians, of the imagery provided by the instance. This function should not be called before ImageryProvider#ready returns true.

maximumLevel :Number

Gets the maximum level-of-detail that can be requested. This function should not be called before ImageryProvider#ready returns true.

minimumLevel :Number

Gets the minimum level-of-detail that can be requested. This function should not be called before ImageryProvider#ready returns true. Generally, a minimum level should only be used when the extent 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.

proxy :Proxy

Gets the proxy used by this provider.

ready :Boolean

Gets a value indicating whether or not the provider is ready for use.

tileDiscardPolicy :TileDiscardPolicy

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. This function should not be called before ImageryProvider#ready returns true.

tileHeight :Number

Gets the height of each tile, in pixels. This function should not be called before ImageryProvider#ready returns true.

tileWidth :Number

Gets the width of each tile, in pixels. This function should not be called before ImageryProvider#ready returns true.

tilingScheme :TilingScheme

Gets the tiling scheme used by the provider. This function should not be called before ImageryProvider#ready returns true.

Methods

getTileCredits

Gets the credits to be displayed when a given tile is displayed.

Parameters:

Name	Type	Description
x	Number	The tile X coordinate.
y	Number	The tile Y coordinate.
level	Number	The tile level;

Throws:

DeveloperError : getTileCredits must not be called before the imagery provider is ready.

Returns:

Credit[] The credits to be displayed when the tile is displayed.

requestImage

Requests the image for a given tile. This function should not be called before ImageryProvider#isReady returns true.

Parameters:

Name	Type	Description
x	Number	The tile X coordinate.
y	Number	The tile Y coordinate.
level	Number	The tile level.

Throws:

DeveloperError : requestImage must not be called before the imagery provider is ready.

Returns:

Promise 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. The resolved image may be either an Image or a Canvas DOM object.

<static> loadImage

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.

Parameters:

Name	Type	Description
url		{String} The URL of the image.

Returns:

Promise 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. The resolved image may be either an Image or a Canvas DOM object.