import type { RenderWindow } from '../../plugin.types';
import type { RowNode } from '../../../types/row.types';
import type { SlotAxis } from '../time/slot-axis';
import type { EventIndex } from '../data/event-index';
import { type LaneInput } from './lane-layout';
/** Placement of one event bar, in the layer's coordinate space. */
export interface BarPlacement {
    /** Stable key for DOM recycling: `resourceId \0 eventId`. */
    readonly key: string;
    /** Pool handle, for resolving the event. */
    readonly handle: number;
    readonly resourceId: string;
    /** Absolute content-space x. The layer's own translate handles panning. */
    readonly left: number;
    /** Rebased y — see {@link RenderWindow.rowOriginY}. */
    readonly top: number;
    readonly width: number;
    readonly height: number;
    readonly lane: number;
    readonly laneCount: number;
}
/** Tuning for {@link computeBarLayout}. */
export interface BarLayoutOptions {
    /** Vertical inset at the top and bottom of a row. @default 2 */
    readonly rowPaddingY?: number;
    /** Gap between stacked lanes. @default 2 */
    readonly laneGap?: number;
    /**
     * Floor on rendered bar width.
     *
     * Without it a one-minute event in a year view computes to a fraction of a
     * pixel and disappears — worse than being slightly wrong, because the user
     * has no way to find or fix data they cannot see.
     * @default 3
     */
    readonly minWidth?: number;
    /**
     * Ceiling on bars produced in one frame.
     *
     * Past this the bars are narrower than their own text and the view is not
     * communicating anything; the renderer is expected to fall back to a per-row
     * summary. A hard cap also stops one pathological resource from stalling a
     * frame.
     * @default 800
     */
    readonly maxBars?: number;
}
/** Reusable scratch, so a steady-state frame allocates nothing. */
export interface BarLayoutScratch {
    handles: number[];
    lanes: LaneInput[];
}
/** Creates the scratch buffers {@link computeBarLayout} reuses across frames. */
export declare function createBarLayoutScratch(): BarLayoutScratch;
/** Result of one layout pass. */
export interface BarLayoutResult {
    readonly bars: BarPlacement[];
    /** `true` when {@link BarLayoutOptions.maxBars} clipped the output. */
    readonly truncated: boolean;
}
/**
 * Computes every event bar for one frame.
 *
 * **Pure**: it reads no DOM and measures nothing, which is what makes the whole
 * positioning story unit-testable in the `node` environment — the package has no
 * jsdom, and its DOM stub returns zeros from `getBoundingClientRect`. The
 * renderer that consumes this is a thin loop that writes `transform`.
 *
 * ## The rebasing contract
 *
 * `RowNode.top` is absolute content-space, but the grid writes
 * `top - rowOriginY` into its row stylesheet and translates the panels by
 * `--pg-row-offset-y`. Bars must live in that same rebased space or they drift
 * from their resource rows on every scrolled frame. Hence `top` here is always
 * `row.top - window.rowOriginY`, and a layer mounted with `followRowOrigin`
 * needs no vertical repositioning on scroll at all.
 *
 * Horizontally the mirror image: `left` is absolute content-space and a layer
 * mounted with `followScrollX` tracks panning through its own transform. So in
 * the steady state a pure scroll changes **no** bar's geometry — the layout is
 * recomputed but produces identical numbers, and the renderer's diff writes
 * nothing.
 *
 * @param window - The grid's render window for this frame.
 * @param axis - Time-to-pixel projection.
 * @param index - Event index to query.
 * @param resourceIdOf - Maps a grid row to a resource id; return `null` for
 *   rows that are not resources (group headers, detail rows, summaries).
 * @param scratch - Reused buffers from {@link createBarLayoutScratch}.
 */
export declare function computeBarLayout(window: RenderWindow, axis: SlotAxis, index: EventIndex, resourceIdOf: (row: RowNode) => string | null, scratch: BarLayoutScratch, options?: BarLayoutOptions): BarLayoutResult;
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