VectorPmTilesAsyncLayer¶
Namespace: ThinkGeo.Core
Renders vector PMTiles content by reading tiles from a local archive and applying a Mapbox style definition.
public class VectorPmTilesAsyncLayer : MvtTilesAsyncLayer, IHttpRequestService, IFeatureLayer
Inheritance object → LayerBase → AsyncLayer → XyzTilesAsyncLayer → MvtTilesAsyncLayer → VectorPmTilesAsyncLayer
Implements IHttpRequestService, IFeatureLayer
Properties¶
FilePath¶
Gets or sets the path to the PMTiles archive that supplies vector tile data.
public string FilePath { get; set; }
Property Value¶
MaxZoomOfData¶
Gets the deepest zoom level the archive holds tiles for, read from its header when the layer opens; deeper zooms draw the tiles of this one, magnified.
public int MaxZoomOfData { get; private set; }
Property Value¶
Header¶
Gets the header of the opened PMTiles archive, or null before the layer is opened.
public PmTilesHeader Header { get; }
Property Value¶
MetadataJson¶
Gets the raw JSON metadata embedded in the PMTiles archive.
public string MetadataJson { get; }
Property Value¶
HttpClient¶
Gets or sets the MvtTilesAsyncLayer.HttpClient instance that will be used to download remote tiles.
public HttpClient HttpClient { get; set; }
Property Value¶
WebProxy¶
Gets or sets the web proxy that should be applied when issuing HTTP requests.
public IWebProxy WebProxy { get; set; }
Property Value¶
TimeoutInSeconds¶
Gets or sets the request timeout, in seconds, used for outbound HTTP calls.
public int TimeoutInSeconds { get; set; }
Property Value¶
Credentials¶
Gets or sets the credentials that are supplied when authenticating against secured tile services.
public ICredentials Credentials { get; set; }
Property Value¶
UserAgent¶
Gets or sets the custom user-agent string that is attached to outbound HTTP requests.
public string UserAgent { get; set; }
Property Value¶
LabelDisplayMode¶
Gets or sets how labels should be drawn for the styles in this layer.
public LabelDisplayMode LabelDisplayMode { get; set; }
Property Value¶
StyleJsonUri¶
Gets or sets the URI of the Mapbox style JSON that describes the visual appearance of the tiles.
public string StyleJsonUri { get; set; }
Property Value¶
VectorTileCache¶
Gets or sets the cache that stores vector tiles retrieved from remote sources.
public FileTileCache VectorTileCache { get; set; }
Property Value¶
ScaleFactor¶
Gets or sets the factor that scales sprite icons defined in the style JSON.
public float ScaleFactor { get; set; }
Property Value¶
ProjectionConverter¶
Gets or sets the projection converter used to transform coordinates during rendering.
public ProjectionConverter ProjectionConverter { get; set; }
Property Value¶
TileMatrixSet¶
Gets or sets the tile matrix set describing the XYZ grid.
public TileMatrixSet TileMatrixSet { get; set; }
Property Value¶
TileWidth¶
Gets or sets the TileWidth.
public int TileWidth { get; set; }
Property Value¶
TileHeight¶
Gets or sets the TileHeight.
public int TileHeight { get; set; }
Property Value¶
MaxExtent¶
This is the full extent of the matrix griding the xyz tiles. It's NOT the bounding box of the data itself.
public RectangleShape MaxExtent { get; set; }
Property Value¶
MapUnit¶
Gets or sets the MapUnit.
public GeographyUnit MapUnit { get; set; }
Property Value¶
HasBoundingBox¶
Gets or sets the HasBoundingBox.
public bool HasBoundingBox { get; }
Property Value¶
MaxConcurrentTileLoads¶
Maximum number of tiles whose load operation can be in flight at the same time during a single draw pass. Default is 4.
public int MaxConcurrentTileLoads { get; set; }
Property Value¶
Remarks:
A "load" here covers either a cache lookup, a local file read (e.g. MBTiles SQLite), or, on miss / for remote sources, an outbound HTTP request — the cap applies regardless of source.
Lower the value (down to 1, which restores the pre-14.5 sequential behavior) when the source service or your egress network rate-limits aggressive bursts — common signals are server-only "no images appear" symptoms while local development works, or HTTP 429 / empty responses surfacing in LayerBase.DrawingExceptionMode captures. Raise it for high-throughput tile servers you control or for cache-only scenarios where every load is a local read.
Name¶
Gets or sets the display name for the layer.
public string Name { get; set; }
Property Value¶
string
The name used to identify the layer within UI components such as legends.
Remarks:
The name is user defined. Assign a descriptive value so tooling such as legends and layer lists can surface a meaningful label to end users.
IsOpen¶
Gets a value indicating whether the layer is currently open.
public bool IsOpen { get; }
Property Value¶
bool
true if the layer has completed its open routine; otherwise, false.
Remarks:
This method is the concrete wrapper for the abstract method IsOpenCore. Various methods on the Layer require that it be in an open state. If one of those methods is called when the state is not open, then the method will throw an exception. To enter the open state, you must call the Layer Open method. The method will raise an exception if the current Layer is already open.
As this is a concrete public method that wraps a Core method, we reserve the right to add events and other logic to pre- or post-process data returned by the Core version of the method. In this way, we leave our framework open on our end, but also allow you the developer to extend our logic to suit your needs. If you have questions about this, please contact our support team as we would be happy to work with you on extending our framework.
IsVisible¶
Gets or sets a value indicating whether the layer is visible.
public bool IsVisible { get; set; }
Property Value¶
bool
true to draw the layer; otherwise, false.
Remarks:
If this property is set to false, the layer will not draw. We ensure this in the Draw method. This is useful for legends and other controls that control the visibility of layers.
Projection¶
Gets the projection of the layer.
public Projection Projection { get; set; }
Property Value¶
DrawingExceptionMode¶
Gets or sets how drawing exceptions are handled when the layer renders.
public DrawingExceptionMode DrawingExceptionMode { get; set; }
Property Value¶
Background¶
Gets or sets the background color used when rendering the layer.
public GeoColor Background { get; set; }
Property Value¶
GeoColor
The fill applied to areas not covered by layer content.
Transparency¶
Gets or sets the amount of transparency applied to the rendered image.
public float Transparency { get; set; }
Property Value¶
float
A value between 0 (fully transparent) and 255 (fully opaque).
Opacity¶
Gets or sets the opacity applied to the rendered image.
public float Opacity { get; set; }
Property Value¶
float
A value between 0.0 (fully transparent) and 1.0 (fully opaque).
BlueTranslation¶
Gets or sets the intensity adjustment applied to the blue channel.
public float BlueTranslation { get; set; }
Property Value¶
float
A value between -255 and 255 representing the blue channel translation.
RedTranslation¶
Gets or sets the intensity adjustment applied to the red channel.
public float RedTranslation { get; set; }
Property Value¶
float
A value between -255 and 255 representing the red channel translation.
GreenTranslation¶
Gets or sets the intensity adjustment applied to the green channel.
public float GreenTranslation { get; set; }
Property Value¶
float
A value between -255 and 255 representing the green channel translation.
KeyColors¶
Gets the collection of key colors that should be rendered as transparent.
public Collection<GeoColor> KeyColors { get; }
Property Value¶
Remarks:
Attempting to access this collection when the associated GeoCanvas does not support key colors (see GeoCanvas.SupportKeyColor) results in an exception. Add colors to this collection to ensure they render as transparent.
IsNegative¶
Gets or sets a value indicating whether the image should be rendered with inverted colors.
public bool IsNegative { get; set; }
Property Value¶
bool
true to invert the color channels; otherwise, false.
IsGrayscale¶
Gets or sets a value indicating whether the image should be converted to grayscale prior to rendering.
public bool IsGrayscale { get; set; }
Property Value¶
bool
true to apply a grayscale filter; otherwise, false.
ConcurrentAccess¶
Gets or sets how this layer behaves when more than one thread wants to draw it at once, and what a caller who wants concurrency should therefore do with it.
public ConcurrentAccess ConcurrentAccess { get; set; }
Property Value¶
ConcurrentAccess
unless the layer says otherwise: callers take turns on the one instance, which is what the screen renderer has done with a layer that did not say otherwise since this question was first asked.
Remarks:
A FeatureLayer that is not given a value of its own answers with its FeatureLayer.FeatureSource's, so a layer and the source it reads through cannot disagree about this.
ThreadSafe¶
Gets or sets the threading guarantees provided by the layer implementation.
public ThreadSafetyLevel ThreadSafe { get; set; }
Property Value¶
ThreadSafetyLevel
The level of thread safety that callers can expect when interacting with the layer.
Remarks:
Replaced by LayerBase.ConcurrentAccess and kept only so that code written against it is told, by name, what to use instead. It does not compile, so there is never a question of which of the two a caller meant: there is one value, and it is the other one. That matters because the translation was lossy in one direction - writing ThreadSafetyLevel.Unsafe could only pick ConcurrentAccess.UnsafeLock, and would silently undo a layer or source that had said ConcurrentAccess.UnsafeClone.
ColorMappings¶
Gets the color translation map that will be applied when rendering the layer.
public Dictionary<GeoColor, GeoColor> ColorMappings { get; }
Property Value¶
Dictionary<GeoColor, GeoColor>
WrappingMode¶
Gets or sets how the layer wraps when the map extent crosses world boundaries.
public WrappingMode WrappingMode { get; set; }
Property Value¶
WrappingExtent¶
Gets or sets the geographic extent to use when wrapping is enabled.
public RectangleShape WrappingExtent { get; set; }
Property Value¶
Constructors¶
VectorPmTilesAsyncLayer()¶
Initializes a new instance of the VectorPmTilesAsyncLayer class.
public VectorPmTilesAsyncLayer()
VectorPmTilesAsyncLayer(string)¶
Initializes a new instance of the VectorPmTilesAsyncLayer class for the specified PMTiles file.
public VectorPmTilesAsyncLayer(string filePath)
Parameters¶
filePath string
The vector PMTiles file to open.
VectorPmTilesAsyncLayer(string, string)¶
Initializes a new instance of the VectorPmTilesAsyncLayer class for the given PMTiles file and style JSON.
public VectorPmTilesAsyncLayer(string filePath, string styleJsonFilePath)
Parameters¶
filePath string
The vector PMTiles file to open.
styleJsonFilePath string
The Mapbox style JSON that describes how the tiles should draw.
Methods¶
A(string, Int32&)¶
internal bool A(string , Int32& )
Parameters¶
`` string
`` Int32&
Returns¶
OpenAsyncCore(CancellationToken)¶
Opens the layer, initializes the PMTiles archive, and loads metadata.
protected Task OpenAsyncCore(CancellationToken cancellationToken)
Parameters¶
cancellationToken CancellationToken
The token that can be used to cancel the operation.
Returns¶
GetBoundingBoxCore()¶
Gets the bounding box for the PMTiles dataset.
protected RectangleShape GetBoundingBoxCore()
Returns¶
RectangleShape
The bounding box either in the dataset projection or converted to the external projection.
GetTileAsyncCore(string, int, int, int, CancellationToken)¶
Reads the requested tile bytes directly from the PMTiles archive.
protected Task<Tile> GetTileAsyncCore(string requestTemplate, int zoom, int x, int y, CancellationToken cancellationToken)
Parameters¶
requestTemplate string
zoom int
x int
y int
cancellationToken CancellationToken
Returns¶
GetFeaturesInsideBoundingBoxAsync(string, RectangleShape, double, int, CancellationToken)¶
Gets the features for the specified extent while honoring the maximum zoom level advertised by the PMTiles header.
protected Task<Dictionary<string, Collection<Feature>>> GetFeaturesInsideBoundingBoxAsync(string requestTemplate, RectangleShape extent, double scale, int maxZoomOfData, CancellationToken cancellationToken)
Parameters¶
requestTemplate string
extent RectangleShape
scale double
maxZoomOfData int
cancellationToken CancellationToken
Returns¶
Task<Dictionary<string, Collection<Feature>>>
CloseAsyncCore(CancellationToken)¶
Closes the PMTiles archive and releases resources.
protected Task CloseAsyncCore(CancellationToken cancellationToken)
Parameters¶
cancellationToken CancellationToken
Returns¶
Events¶
SendingHttpRequest¶
Occurs immediately before an HTTP request for a vector tile is sent.
public event EventHandler<SendingHttpRequestMessageEventArgs> SendingHttpRequest;
ReceivedHttpResponse¶
Occurs after an HTTP response is received for a previously issued tile request.
public event EventHandler<ReceivedHttpResponseMessageEventArgs> ReceivedHttpResponse;
DrawingException¶
Occurs when the DrawingException event is raised.
public event EventHandler<DrawingExceptionLayerEventArgs> DrawingException;
DrawnException¶
Occurs when the DrawnException event is raised.
public event EventHandler<DrawnExceptionLayerEventArgs> DrawnException;