/**
 * Pre-computed layout of a single content line.
 *
 * - Grapheme clusters and ANSI codes are separated so row emission never
 *   splits a sequence or miscounts a width.
 * - Row boundaries and per-row active styles are computed once per line and
 *   screen width, then reused on every render.
 */
export interface LineLayout {
    /** Grapheme clusters, excluding ANSI codes. */
    chars: string[];
    /** Visual width of each cluster. */
    widths: number[];
    /** prefix[i] - total visual width of chars[0..i-1]. */
    prefix: number[];
    /** Cluster index each ANSI code is anchored before. */
    codeIdx: number[];
    /** ANSI codes in order of appearance. */
    codes: string[];
    /** Cluster index starting each wrapped row. */
    rowStart: number[];
    /** Active ANSI style prefix at each wrapped row start. */
    rowStyle: string[];
}
/** Bumped whenever the cached layouts stop applying. */
export declare const layoutGeneration: () => number;
/**
 * Returns the cached layout for a line, building it on first access.
 *
 * - The cache is invalidated when the screen width changes.
 *
 * @param line - The raw content line.
 * @returns The line's layout for the current screen width.
 */
export declare function getLayout(line: string): LineLayout;
/**
 * Whether any style is still open at the end of a string.
 *
 * A full reset is not the only way a style closes: ESC[27m ends the
 * inverse ESC[7m opened before it, and SGR_CLOSERS above knows every
 * such pairing. withReset used to look for a reset code alone, so a
 * line that closed its inverse properly looked unterminated and got a
 * second, redundant reset appended -- which less does not emit.
 *
 * @param text - The text to scan.
 */
export declare function stylesOpen(text: string): boolean;
/**
 * Where the screen row that begins at `from` ends - one step of
 * buildRowStarts, taken from an arbitrary character rather than from a
 * boundary.
 *
 * less's forw_line reads from wherever table[TOP] points and stops when
 * the line no longer fits, so a row's extent depends on where it
 * STARTS. Under a plain width that is just from + width, but
 * --wordwrap breaks at spaces, so the answer cannot be translated from
 * the boundary grid - it has to be walked.
 */
export declare function rowEndFrom(layout: LineLayout, from: number): number;
/**
 * The index into the raw line string that a display-CHARACTER offset
 * names.
 *
 * The two spaces differ on every styled line - the layout keeps its
 * escape codes in a separate list, so a character index is not a
 * string index - and on every line with clusters or wide characters.
 * Anything holding a position (the screen table, the view's top) works
 * in character space; anything scanning the text itself needs this.
 */
export declare function stringIndexAt(layout: LineLayout, at: number): number;
/**
 * The display-CHARACTER offset naming a raw string index - the
 * inverse of stringIndexAt, for coming back from a position measured
 * in the line's own bytes.
 */
export declare function charIndexAt(layout: LineLayout, at: number): number;
/**
 * The drawn text of the characters in [from, to), with the style in
 * force at `from` reopened so the row stands alone like less's (less
 * re-emits attributes per row through at_switch).
 *
 * A space run --wordwrap swallowed at the break is inside the range
 * but past the screen edge, so the width guard still drops it.
 */
export declare function emitRange(layout: LineLayout, from: number, to: number): string;