/**
 * Common system fonts that are NOT on Google Fonts but render fine everywhere,
 * mapped onto the PDF base-14 standard fonts. Resolving these locally means:
 *   - pdf-export embeds nothing — it just names the base-14 font, which pdfkit
 *     has built-in AFM metrics for (accurate Latin advance widths for free).
 *   - psd-import gets accurate aggregate metrics without a network fetch.
 *   - svg-import / the browser canvas use the native family name directly.
 *
 * This is what lets strict mode not fail on Arial/Times/Courier, and matches
 * core's canonical fallback to Arial (Helvetica is the metric-equivalent
 * base-14 stand-in).
 *
 * Coverage is Latin-1 (base-14 limitation, accepted tradeoff). Non-Latin text
 * in a system font falls through to the normal fallback path.
 */
export interface SystemFontMetrics {
    /** Ascender as a fraction of em (1000 upm AFM values / 1000). */
    ascent: number;
    descent: number;
    capHeight: number;
    /** Rough average glyph advance as a fraction of em, for coarse layout. */
    avgAdvance: number;
}
export interface SystemFontResolution {
    /** Full base-14 pdfkit font name for the requested variant. */
    pdfFont: string;
    /** Family name usable directly in CSS / the browser canvas. */
    cssFamily: string;
    metrics: SystemFontMetrics;
}
/**
 * Normalize a raw fontFamily to a lookup key: lowercase, trimmed, quotes
 * stripped, and reduced to the first family in a CSS stack ("Arial, sans-serif"
 * → "arial").
 */
export declare function normalizeFamily(family: string): string;
/**
 * Resolve a system font, or `null` if the family isn't a known system font
 * (callers then try registered URLs / Google / fallback).
 */
export declare function resolveSystemFont(family: string, bold?: boolean, italic?: boolean): SystemFontResolution | null;
/** Whether a raw family name maps to a known system font. */
export declare function isSystemFont(family: string): boolean;