/**
 * This Source Code is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 *
 * Copyright (c) Infonomic Company Limited
 */
export interface StripMeasurements {
    /**
     * Intrinsic content width of the tablist row.
     *
     * The row is laid out at `max-content`, so this is the width the tabs want
     * regardless of how much room the viewport currently gives them. A row that
     * shrank to its container would report the container's width back and the
     * strip could never detect overflow at all.
     */
    rowWidth: number;
    /**
     * Usable width of the strip container.
     *
     * Independent of whether the trigger is rendered — the container is sized by
     * the layout above it, not by its own children.
     */
    containerWidth: number;
    /** Width the overflow trigger occupies when it is rendered. */
    triggerWidth: number;
    /** Gap between the viewport and the trigger. */
    triggerGap: number;
    /** Current horizontal scroll offset of the viewport. */
    scrollLeft: number;
}
export interface StripState {
    /** Whether the row needs the scrolling viewport and the overflow trigger. */
    overflowing: boolean;
    /** Width available to the scrolling viewport. */
    viewportWidth: number;
    /** Whether the viewport is scrolled fully left (hides the leading fade). */
    atStart: boolean;
    /** Whether the viewport is scrolled fully right (hides the trailing fade). */
    atEnd: boolean;
}
export interface RevealMeasurements {
    viewportWidth: number;
    scrollLeft: number;
    /** The tab's offset from the start of the row. */
    tabOffsetLeft: number;
    tabWidth: number;
    rowWidth: number;
    padding?: number;
}
/**
 * Resolve whether the strip overflows, and where it sits within its scroll
 * range.
 *
 * Overflow is decided against the bare container, and deliberately takes no
 * account of the trigger: a row that fits the container fits, and reserving
 * the trigger's width first would summon a menu for tabs that were never cut
 * off. The trigger is subtracted only afterwards, to size the viewport it now
 * shares the container with.
 *
 * That ordering is also what keeps the result stable. The trigger's presence
 * changes the viewport but never `containerWidth` — which the layout above
 * sets — and never `rowWidth`, which the row holds at `max-content`. So the
 * overflow answer cannot feed back into its own inputs.
 */
export declare function computeStripState({ rowWidth, containerWidth, triggerWidth, triggerGap, scrollLeft, }: StripMeasurements): StripState;
/**
 * The scroll offset that brings one tab into view, or `null` when the tab is
 * already visible and the viewport should be left untouched.
 *
 * Returning `null` rather than the current offset is the point: this runs on
 * selection and on focus, and writing `scrollLeft` unconditionally would
 * cancel a scroll the reader is in the middle of.
 */
export declare function computeRevealScroll({ viewportWidth, scrollLeft, tabOffsetLeft, tabWidth, rowWidth, padding, }: RevealMeasurements): number | null;