Class HeadlessTileRenderer

Namespace

EncDotNet.S100.Datasets.Pipelines

Assembly

EncDotNet.S100.Datasets.Pipelines.dll

Renders a prepared HeadlessCompositeScene as XYZ Web-Mercator raster tiles (see XyzTileGrid).

public sealed class HeadlessTileRenderer

Inheritance

object

HeadlessTileRenderer

Inherited Members

object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.ReferenceEquals(object, object)

object.ToString()

Remarks

Prepare the scene with HonorScaleVisibility on, so each zoom level shows only what is visible at its scale, and EnableSeamWrap off, because this renderer draws the data on either side of the antimeridian itself, and KeepAreaSymbolsInView off, so a surface across several tiles keeps one symbol rather than one per tile.

Tiles are rendered in blocks (TileBlock) and cut apart. The renderer maps world to pixels with one continuous transform and does not clip geometry to the viewport, and it keeps point symbols and text whose anchor lies up to PointCullMarginPx pixels outside it. So a feature crossing a tile edge draws identically on both sides, whether the two tiles share a block or not.

Each zoom level is evaluated at one scale denominator, measured at ReferenceLatitude, rather than at each tile's own latitude. Measuring per tile would switch SCAMIN at row boundaries and cut features off along tile edges.

The renderer is immutable; Render(TileBlock) may be called concurrently.

Constructors

HeadlessTileRenderer(HeadlessCompositeScene, HeadlessTileOptions?)

Creates a tile renderer over a prepared scene.

public HeadlessTileRenderer(HeadlessCompositeScene scene, HeadlessTileOptions? options = null)

Parameters

scene HeadlessCompositeScene

The prepared scene.

options HeadlessTileOptions

Tile options; defaults when null.

Properties

TilePixelSize

The edge length of each tile image, in pixels.

public int TilePixelSize { get; }

Property Value

int

Methods

PlanBlocks(int, IReadOnlyList<int>, int, int, int)

Splits the tiles of one zoom level into blocks of at most blockSize × blockSize tiles, aligned to multiples of blockSize so neighbouring runs share block boundaries.

public static IReadOnlyList<TileBlock> PlanBlocks(int zoom, IReadOnlyList<int> columns, int firstRow, int lastRow, int blockSize)

Parameters

zoom int

The zoom level.

columns IReadOnlyList<int>

The tile columns to cover, ascending (see Columns(int, double, double)).

firstRow int

The first tile row to cover.

lastRow int

The last tile row to cover.

blockSize int

The block edge length, in tiles.

Returns

IReadOnlyList<TileBlock>

The blocks, row-major.

Render(TileBlock)

Renders a block of tiles and cuts it into one image per tile.

public IReadOnlyList<HeadlessTile> Render(TileBlock block)

Parameters

block TileBlock

The block to render. It must lie inside the grid.

Returns

IReadOnlyList<HeadlessTile>

The tiles, row-major. The caller disposes them.

ScaleDenominator(int)

The scale denominator zoom is rendered at: ScaleDenominator(int, double) at the reference latitude.

public double ScaleDenominator(int zoom)

Parameters

zoom int

The zoom level.

Returns

double