import type { LocaleTag } from '../types.js';
import { type HyphenationRules } from '../hyphenate.js';
import type { MeasurementCache } from './types.js';
/**
 * Build a CSS font shorthand string for canvas / pretext.
 * Example: "75px EB Garamond"
 */
export declare function buildFontString(fontFamily: string, fontSizePx: number, weight?: string, style?: string): string;
/** Whether a `fontFamily` value is a CSS font stack (`'EB Garamond',
 *  Georgia, serif`) rather than one family: it has a comma outside quotes. */
export declare function isFontStack(fontFamily: string): boolean;
/**
 * The one family a `fontFamily` value sets text in. A `fontFamily` names a
 * single family: canvas, HTML and PDF must measure and paint the same face,
 * and the PDF embeds a font per family, with no fallback chain. A CSS font
 * stack is therefore cut to its first family (`'EB Garamond', serif` →
 * `EB Garamond`) instead of being read as one family whose name has a
 * comma in it — which matched no face and measured with a fallback font.
 * Any other value comes back unchanged (a comma inside quotes is part of
 * the name).
 */
export declare function primaryFontFamily(fontFamily: string): string;
/**
 * A family name the CSS font shorthand would not take bare — a word that
 * starts with a digit ("Optima 105", "DIN Pro 120"), a character outside
 * letters, digits, spaces, hyphens and underscores — goes in double quotes;
 * canvas silently ignores the whole shorthand otherwise. Plain names stay
 * bare (the existing font-string cache keys), and a name already quoted is
 * left alone. A font stack sets in its first family (see
 * {@link primaryFontFamily}).
 */
export declare function quoteFamily(fontFamily: string): string;
/**
 * Initializes the hyphenator for a given locale (any BCP 47 tag; see
 * `matchHyphenationLocale`). Must be called before measureBlock is used with
 * hyphenation.
 */
export declare function initHyphenator(locale: LocaleTag, rules?: HyphenationRules): void;
/**
 * Clear pretext's internal measurement caches and the engine's own
 * text-width cache. Call this after fonts finish loading (or are removed)
 * to ensure accurate measurements.
 */
export declare function clearMeasurementCache(): void;
/**
 * Drop what was measured in `families` (#629): the engine's widths of
 * those families and, at the next lookup, the blocks of every
 * `MeasurementCache` that set text in them. Pretext's own cache holds no
 * family index and is cleared whole. Called when faces of these families
 * arrive or leave; {@link clearMeasurementCache} drops every family.
 */
export declare function evictFontFamilies(families: Iterable<string>): void;
export declare function createMeasurementCache(): MeasurementCache;
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