import type { GlyphMetrics } from './textTexture.js';
/** Placement of one rasterized label inside the atlas, in device pixels. */
export interface GlyphSlot extends GlyphMetrics {
    x: number;
    y: number;
}
/**
 * Packs the labels of a frame into one canvas and uploads them in a single
 * copy. `copyExternalImageToTexture` costs about 1.2 ms whenever its source
 * canvas changed since the last copy, regardless of the region size, so a
 * texture per label made a rotating radial tree spend 250 ms a frame in the
 * driver.
 *
 * Slots survive across frames. Growing or clearing mints a new texture, and the
 * one it replaces stays alive until the frame is submitted, so only the batch
 * currently being packed (which shares one bind group) has to be protected.
 */
export declare class TextAtlas {
    private readonly _device;
    private readonly _release;
    private readonly _max;
    private readonly _canvas;
    private readonly _c2d;
    private readonly _slots;
    private _texture;
    private _size;
    private _shelfY;
    private _shelfHeight;
    private _cursorX;
    private _dirty;
    private _spilled;
    private _batchArea;
    private _lastBatchArea;
    /** `release` takes a texture the atlas replaced, which a queued draw may still hold. */
    constructor(_device: GPUDevice, _release: (texture: GPUTexture) => void);
    get context(): CanvasRenderingContext2D;
    get texture(): GPUTexture;
    get size(): number;
    /**
     * Starts a batch of lookups that will share one bind group, growing or
     * clearing the atlas first if the last batch of this size would not fit in
     * what is left. Nothing else replaces the texture, so a batch always packs
     * into the one it read.
     */
    begin(): void;
    /** Slot for a label already packed. */
    find(key: string): GlyphSlot | undefined;
    /**
     * Reserves space for a label. Returns null when it does not fit, and the
     * caller falls back to a texture of its own.
     */
    alloc(key: string, metrics: GlyphMetrics): GlyphSlot | null;
    /** Uploads whatever was drawn since the last flush. */
    flush(): void;
    private _place;
    private _reset;
    private _markDirty;
}