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SharedTileset2D (Experimental)

_SharedTileset2D is the experimental shared tile-content cache used by _SharedTile2DLayer. It owns tile headers, tile payloads, request scheduling, cache eviction, loaders.gl TileSource metadata, live stats, and lifecycle subscriptions. Per-viewport selection and visibility are intentionally owned by the layer's internal views instead of the tileset.

import {
  _SharedTileset2D as SharedTileset2D,
  sharedTile2DDeckAdapter
} from '@deck.gl/geo-layers';
import type {SharedTileset2DProps} from '@deck.gl/geo-layers';

const props: SharedTileset2DProps<ImageBitmap> = {
  adapter: sharedTile2DDeckAdapter,
  getTileData: async ({index, signal}) => {
    const {x, y, z} = index;
    const response = await fetch(`https://tile.openstreetmap.org/${z}/${x}/${y}.png`, {signal});
    return createImageBitmap(await response.blob());
  }
};

const tileset = new SharedTileset2D(props);

Construction

import {_SharedTileset2D as SharedTileset2D} from '@deck.gl/geo-layers';
import type {
  SharedRefinementStrategy,
  SharedTileset2DAdapter,
  SharedTileset2DBaseProps,
  SharedTileset2DProps,
  SharedTileset2DTileContext,
  SharedTileset2DTraversalContext
} from '@deck.gl/geo-layers';

new SharedTileset2D<TileDataT, ViewStateT>(props: SharedTileset2DProps<TileDataT, ViewStateT>);
SharedTileset2D.fromTileSource<TileDataT>(tileSource, props);

Provide either getTileData or tileSource. A shared tileset also needs an adapter before traversal is used. _SharedTile2DLayer installs sharedTile2DDeckAdapter automatically for deck.gl viewport traversal; applications constructing the tileset directly should usually pass that adapter themselves.

TileSource metadata

When created from a loaders.gl TileSource, _SharedTileset2D calls getMetadata() asynchronously and adopts supported minZoom, maxZoom, and boundingBox metadata. Explicit tileset options win over metadata. Replacing the tileSource ignores late metadata from the previous source.

Ownership

An external _SharedTileset2D can be passed to one or more _SharedTile2DLayer instances. Those layers do not finalize the external tileset. The owner should call tileset.finalize() when the shared cache is no longer needed.

Runtime API

  • tiles, selectedTiles, visibleTiles, loadingTiles, and cacheByteSize expose current shared cache state.
  • stats is a @probe.gl/stats Stats object with tile cache, visibility, loading, eviction, and consumer counters.
  • setOptions() updates effective tileset options. Pass {replace: true} as the second argument to replace prior caller options instead of merging them.
  • reloadAll() marks selected tiles stale and drops unselected cached tiles.
  • subscribe() listens for tile load, tile error, tile unload, metadata/config update, metadata error, and stats change events.
  • finalize() aborts in-flight requests and clears the shared cache.

Refinement

SharedRefinementStrategy supports 'best-available', 'no-overlap', and 'never'. Unlike TileLayer, _SharedTileset2D does not accept a custom refinement callback because one tile header may be selected or visible in one viewport and hidden in another.