import { IndicatorSeries } from '../../base/Indicator.js';
import type { HilbertCycleState } from './HilbertTransform.js';
type HTTrendlineState = HilbertCycleState & {
    barsTotal: number;
    cycleAverages: number[];
    prices: number[];
    smoothPeriod: number;
};
export declare class HTTrendline extends IndicatorSeries<number, HTTrendlineState> {
    protected state: HTTrendlineState;
    getRequiredInputs(): number;
    update(price: number, replace: boolean): number | null;
}
export {};