/**
 * Whether a line may end after the em or en dash `dash`, set closed between
 * `prev` and `next` (the characters around it; undefined at the edge of the
 * text, or where a space stands): "say—that’s", "riddles.—I", "Hamburg–Berlin".
 * `beforePrev` is the character before `prev`, read the same way.
 * The dash is the Unicode line-breaking class B2 (em) or BA (en), both of
 * which allow a break after them. Never after a dash that opens an aside or a
 * line of dialogue: a space before it ("—dijo"), or a space and a quotation
 * mark (`said "—Hola`, German `sagte »—Ich`). A straight quote, `»`, `”` or
 * `’` before the dash may open a quote as well as close one, so it counts as
 * closing only after a letter, a digit or closing punctuation ("\"no\"—and",
 * "boys'—and", "«no»—y"), and `»` also after a no-break space (French
 * "« non »—et"). `“` and `«`, which German and Danish close with, count as
 * closing only after a letter, a digit, `.`, `!`, `?` or `…` ("„nein“—und",
 * "»nej«—og"). Never before punctuation ("él—,"), a quotation mark
 * or a bracket ("thinking—\" and", "says—“no”", "says—(no)"), inside a run of
 * dashes ("——"), or inside a range of numbers set with an en dash
 * ("1914–1918"). A quote after a dash may close the speech as well as open
 * one, and UAX #14 allows no break before it; pretext, which sets plain text
 * line by line, keeps a dash with the quote or bracket after it, so both
 * breakers agree.
 */
export declare function breaksAfterDash(prev: string | undefined, dash: string, next: string | undefined, beforePrev?: string): boolean;
/** Whether `ch` is an em or an en dash. */
export declare function isDash(ch: string | undefined): boolean;
/** Whether `text` holds a compound (see {@link COMPOUND_RE}). A soft hyphen
 *  next to the hyphen hides it, as it hides it from the breakers. */
export declare function hasCompound(text: string): boolean;
/**
 * Whether a line may end after a hyphen the text carries, between `prev`
 * and `next` (the characters around it): between two letters only
 * ("meta-analyses", "UNE-EN"), never in "-5", "1-2" or "pre-(war)". The
 * line then ends on that hyphen and nothing is added.
 */
export declare function breaksAfterHardHyphen(prev: string | undefined, next: string | undefined): boolean;
/**
 * How far a ragged line may fall short of its measure at the cost a
 * justified line pays at its word-spacing limit, in ems of the text: the
 * right-hand "glue" of a ragged setting in Knuth and Plass's model (TeX's
 * `\rightskip` of `0pt plus 3em`). A shorter line costs less, a line short by
 * more than this is priced like one stretched past the limit.
 */
export declare const RAGGED_STRETCH_EM = 3;
/** The size of a CSS font string, in px (the `16px` of `italic 16px Serif`);
 *  16 when it names none. */
export declare function fontSizePxOf(font: string): number;
/** The stretch a ragged line of `font` gets in the Knuth–Plass model (see
 *  {@link RAGGED_STRETCH_EM}). */
export declare function raggedStretchPx(font: string): number;
/** The zero-width space U+200B: a break opportunity the author typed,
 *  with no width and nothing added at the line end. */
export declare const ZERO_WIDTH_SPACE = "\u200B";
/** See {@link getSlashBreaks}. */
export declare function setSlashBreaks(on: boolean): void;
/** Whether a line may end after a slash between two words (see
 *  {@link slashBreakIndices}); also whether a word wider than its line is
 *  divided after a slash first. */
export declare function getSlashBreaks(): boolean;
/**
 * Where a line may end after a slash inside a word (#1164), as offsets into
 * `text` (the position after the slash): "entrada/" | "salida",
 * "ACC/" | "AHA/" | "AAPA". The slash stands between two runs of at least
 * three letters or digits, and not between two digits. A unit keeps its
 * slash ("km/h", "m/s", "kg/m³", "km/min", "mg/dL"), and so do a short
 * pair ("and/or", "y/o", "c/Mayor"), a fraction and a date ("1/2",
 * "10/03/2026", "2020/2021"). Nothing is added at the line end, and the
 * next line opens with the word after the slash. A web address is broken
 * at its own joints instead (`urlBreakIndices`). None while
 * {@link getSlashBreaks} is off.
 */
export declare function slashBreakIndices(text: string): number[];
/**
 * `text` with its zero-width spaces taken out, and where each one stood as
 * offsets into the text left (#1164): the rich breaker may end a line
 * there, adds nothing, and the character never reaches the line text (the
 * plain breaker drops it too). Offsets at either end of the text are no
 * break. A text that is only zero-width spaces is left as it is.
 */
export declare function withoutZeroWidthSpaces(text: string): {
    text: string;
    breaks: number[];
};
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