import type { TileSource } from "./tile-source";
/**
 * Async tile fetcher with in-flight dedup and abort-on-zoom-change.
 *
 * Runs inside the renderer worker (the chart's host process). `fetch`
 * and `createImageBitmap` are both available in workers, and the
 * resulting `ImageBitmap` can be uploaded straight to a WebGL2 texture
 * via `gl.texImage2D(..., ImageBitmap)` — no main-thread bounce.
 *
 * The loader does not own GPU resources. Upload to texture happens in
 * the tile layer once an `ImageBitmap` resolves; the layer then drops
 * the bitmap (calling `close()` to free the decoded pixels).
 */
export declare class TileLoader {
    private _inFlight;
    private _onLoad;
    /**
     * Register the "tile arrived" callback. The layer wires this to
     * `chart.requestRender(glManager)` so a newly-loaded tile triggers
     * exactly one extra frame.
     */
    setOnLoad(cb: () => void): void;
    /**
     * Kick off a fetch (or return the in-flight one). The same
     * (source.id, z, x, y) tuple only ever has one outstanding
     * fetch; multiple callers share the result. Rejected fetches
     * (network error, abort) resolve to `null` so callers can skip
     * the tile without try/catch noise on every miss.
     */
    load(source: TileSource, z: number, x: number, y: number): Promise<ImageBitmap | null>;
    /**
     * Abort every in-flight fetch. Called on view teardown / chart
     * destroy. Fetches whose `Response` has already arrived but
     * haven't yet decoded will still complete the decode and resolve
     * to `null` (because `_onLoad` is replaced or the cache is gone)
     * — harmless, no resource leak.
     */
    cancelAll(): void;
    /**
     * Abort just the fetches whose key isn't in the supplied set.
     * The layer calls this on every render with the currently-visible
     * tile set so old-zoom requests don't keep arriving and triggering
     * spurious re-renders after the user has moved on.
     */
    cancelExcept(liveKeys: Set<string>): void;
    private _fetchAndDecode;
}
/**
 * Stable cache key for a tile under a given source. Embedded source id
 * so swapping sources (light/dark) doesn't surface stale tiles.
 */
export declare function tileKey(sourceId: string, z: number, x: number, y: number): string;