import type { FormatContentModelContext, ReadonlyContentModelDocument, ShallowMutableContentModelParagraph } from 'roosterjs-content-model-types';
/**
 * @internal
 */
export declare type HorizontalLineTriggerCharacter = '-' | '=' | '_' | '*' | '~' | '#';
/**
 * @internal exported only for unit test
 *
 * Create a horizontal line and insert it into the model
 *
 * @param model the model to insert horizontal line into
 * @param context the formatting context
 */
export declare function insertHorizontalLineIntoModel(model: ReadonlyContentModelDocument, context: FormatContentModelContext, triggerChar: HorizontalLineTriggerCharacter): void;
/**
 * @internal
 *
 * Check if the current line should be formatted as horizontal line, and insert horizontal line if needed
 *
 * @param editor The editor to check and insert horizontal line
 * @param event The keydown event
 * @returns True if horizontal line is inserted, otherwise false
 */
export declare const checkAndInsertHorizontalLine: (model: ReadonlyContentModelDocument, paragraph: ShallowMutableContentModelParagraph, context: FormatContentModelContext) => boolean;