export interface SfntNaturalLineMetrics {
    unitsPerEm: number;
    lineHeightUnits: number;
    lineHeightMultiplier: number;
    source: 'os2-typo' | 'legacy-win-hhea';
}
/**
 * Read a static SFNT face's design-unit baseline pitch without consulting browser font state.
 * Variable fonts fail closed until their MVAR/axis instance can be applied to these metrics.
 */
export declare function parseSfntNaturalLineMetrics(bytes: ArrayBuffer | ArrayBufferView): SfntNaturalLineMetrics | null;