/**
 * Tab stops in body text (#622).
 *
 * A tab (`:tab`, or a tab character in a paragraph whose style sets stops)
 * is a `space` token of the rich line breaker whose width depends on where
 * its line has got to, so it is resolved while the line is filled
 * ({@link placeTab}), never once per paragraph. A paragraph that holds a
 * tab is set line by line (Knuth–Plass sums its items' widths per candidate
 * line, which a width that depends on the line's start would break), as
 * word processors and InDesign set tabbed text.
 *
 * - A tab goes to the first stop past the text before it, among the stops
 *   after the one the line's previous tab took. `'start'`: the text after
 *   the tab starts at the stop; `'end'`: the text up to the next tab (or the
 *   paragraph's end) ends there; `'center'`: it is centred on it;
 *   `'decimal'`: its first decimal separator stands on it (a run with none
 *   ends there).
 * - Past the last stop, `tabInterval` sets default stops every interval
 *   from the start of the measure; without one, a tab past the last stop is
 *   a word space.
 * - Overrun: when the text before a tab has passed every remaining stop of
 *   its line, an `'end'`, `'center'` or `'decimal'` stop takes the last word
 *   before the tab to the next line with it (the text before the stop sets
 *   narrower, as a contents row narrows its title for its page number), and
 *   a `'start'` stop breaks the line before the tab, so the text after it
 *   starts the next line at its stop. A tab that opens its line and still
 *   finds no stop for the text after it takes no room.
 * - A leader fills the room before the text at the stop, flush with its
 *   end (see `measure/leader.ts`), `gapPx` clear of the text on each side.
 */
import type { TabStopAlign } from '../types.js';
/** A tab stop with its lengths in px (see `TabStop`). `at` is px from the
 *  start edge of the measure, `'end'` that line's end edge, or a share of
 *  the measure. */
export interface TabStopPx {
    at: number | 'end' | {
        percent: number;
    };
    align: TabStopAlign;
    /** The leader's text, or `'rule'`; absent: none. */
    leader?: string;
    /** Room between the text and the leader, and the leader and the stop's
     *  text (px). */
    gapPx: number;
    decimalChar: string;
}
/** The tab stops of a paragraph (`MeasureBlockOptions.tabs`). */
export interface TabSettings {
    stops: readonly TabStopPx[];
    /** Default stops every this many px past the last of {@link stops}. */
    intervalPx?: number;
}
/** The text a tab sends to its stop: from after the tab to the next tab or
 *  the paragraph's end, its width and the width before its first decimal
 *  separator (`undefined` when it holds none). */
export interface TabRun {
    width: number;
    decimalWidth: (char: string) => number | undefined;
}
/** The line a tab is placed on: where its text starts (the line's indent)
 *  and ends (its measure), from the start edge of the measure; the
 *  paragraph's measure (for `%` stops); and the stop the line's previous
 *  tab took (`-Infinity` for none). */
export interface TabLine {
    start: number;
    end: number;
    measure: number;
    usedPos: number;
}
/** A leader set before a stop: its text (empty for a rule) and width, and
 *  where it ends from the tab's start. */
export interface TabLeaderPlacement {
    text: string;
    width: number;
    rule?: true;
    end: number;
}
export type TabPlacement = {
    kind: 'stop';
    width: number;
    pos: number;
    align: TabStopAlign;
    leader?: TabLeaderPlacement;
} | {
    kind: 'space';
} | {
    kind: 'overrun';
    align: TabStopAlign;
};
/** Where a stop stands on a line. */
export declare function tabStopPos(stop: TabStopPx, line: Pick<TabLine, 'end' | 'measure'>): number;
/**
 * Place a tab whose line has got to `x` (see the module comment): the
 * tab's width and leader, a word space, or an overrun the breaker resolves.
 * `oneOff`: the stop of `:tab{at=…}`, the only one such a tab goes to.
 * `leaderWidth` measures a run of leader text as it is painted.
 */
export declare function placeTab(x: number, run: TabRun, line: TabLine, settings: TabSettings | undefined, oneOff: TabStopPx | undefined, leaderWidth: (text: string) => number): TabPlacement;
/** The decimal separator of numbers in `locale` (Western digits): `.` in
 *  English, Chinese, Japanese and Arabic text, `,` in Spanish, Catalan,
 *  Portuguese, French, German… */
export declare function defaultDecimalChar(locale: string | undefined): string;
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