/** Attribute the author adds to each element that should get a dot. */
export declare const SLIDE_ATTR = "data-blossom-slide";
/**
 * Returns the marker targets for a scroller. Mirrors `::scroll-marker`
 * authoring: targets are explicitly opted-in via the `data-blossom-slide`
 * attribute and collected depth-agnostically (at any nesting level), in tree
 * order. There is no implicit detection from `scroll-snap-align` or direct
 * children; if nothing is marked, there are no markers.
 */
export declare function getMarkerTargets(scroller: HTMLElement): HTMLElement[];
/**
 * The redistributed activation position of each target, in tree order (parallel
 * to `getMarkerTargets`). Positions are logical scroll offsets (see
 * `logicalScrollLeft`), so they hold in both LTR and RTL. Scroll-invariant: it
 * depends only on layout, never on the scroll offset, so the host can compute
 * it once on init/resize/mutation and cache it. {@link selectActiveIndex} then
 * maps the live logical scroll offset onto it each frame without touching
 * layout.
 *
 * This is a single-axis (inline) implementation of the geometry behind the CSS
 * Overflow Level 5 "Calculating the Active Scroll Marker" algorithm (§3.1.8,
 * https://drafts.csswg.org/css-overflow-5/#active-scroll-markers-calculation):
 * each target's unclamped scroll-into-view position (respecting its own
 * `scroll-snap-align`), with the leading/trailing unreachable targets
 * redistributed across the `min(scrollport / 8, scrollRange / 2)` edge bands so
 * each gets a distinct activation point.
 */
export declare function getMarkerPositions(scroller: HTMLElement, targets: HTMLElement[]): number[];
/**
 * Maps the current logical scroll offset onto precomputed marker `positions`
 * and returns the tree-order index of the active target. Pure and layout-free,
 * so it can run on every scroll frame; pass the cached `sorted` copy to keep it
 * allocation-free too.
 *
 * The selected position is the largest target position at or before the current
 * position, or — to surface section-header style markers early — one whose
 * nearest smaller target position sits more than half a scrollport behind and
 * which itself sits less than half a scrollport ahead. Ties resolve to the
 * earliest target in tree order.
 */
export declare function selectActiveIndex(positions: number[], position: number, scrollportSize: number, sorted?: number[]): number;
/**
 * The scroll-invariant geometry needed to resolve the active marker index on
 * the scroll hot loop without layout reads, style reads, or allocations.
 * Subset of the host-maintained `SnapCache`.
 */
export interface ActiveIndexGeometry {
    /** Redistributed activation position per marker, in tree order. */
    activePositions: number[];
    /** `activePositions` sorted ascending. */
    sortedActivePositions: number[];
    /** Whether the scroller's inline axis is right-to-left. */
    rtl: boolean;
}
/**
 * Returns the tree-order index of the active marker target along the inline
 * axis, or -1 when there are none.
 *
 * Convenience wrapper that composes {@link getMarkerPositions} and
 * {@link selectActiveIndex} for live (uncached) use. Pass `cached` geometry
 * from a host-maintained cache to skip the per-call style/layout reads and
 * the sort on the scroll path.
 */
export declare function getActiveMarkerIndex(scroller: HTMLElement, targets: HTMLElement[], cached?: ActiveIndexGeometry): number;