export declare class MeasureTextMetricsError extends Error {
    readonly name: string;
}
export declare class MeasureTextMetricsFontLoadingError extends MeasureTextMetricsError {
    readonly name: string;
}
export declare class MeasureTextMetricsCanvasError extends MeasureTextMetricsError {
    readonly name: string;
}
/**
 * Measure the text metrics of a given font.
 * The function also ensures that the font is loaded before measuring the text.
 * @param font the font string {@link https://developer.mozilla.org/en-US/docs/Web/CSS/font}
 */
export declare function measureTextMetrics(font: string, document: Document): Promise<TextMetrics>;