import { MonoTypeOperatorFunction, Observable } from 'rxjs';
/**
 * Sets the maximum expected FPS baseline. Call this once during application
 * bootstrap so the frame-rate tracker can normalise its score correctly.
 *
 * @param fps - The maximum FPS the display is expected to produce (default 60).
 */
export declare function setMaxFpsOnBootstrap(fps?: number): void;
/** A point-in-time summary of the browser's rendering frame rate. */
export interface FrameRateSnapshot {
    /** Current average FPS over the sliding window. */
    fps: number;
    /** Highest FPS observed during this session (at least `maxFps` from bootstrap). */
    maxFps: number;
    /** Normalised performance score (0 = stalled, 100 = full frame rate). */
    score: number;
}
/**
 * Observable that emits periodic snapshots of the current frame rate,
 * the observed maximum FPS, and a normalised performance score (0-100).
 *
 * Only emits while the document is visible to avoid skewed measurements
 * during background tabs.
 */
export declare const frameRateTracker$: Observable<FrameRateSnapshot>;
/**
 * RxJS operator that throttles emissions to the browser's current frame rate.
 * Trailing values are emitted so the latest state is never lost.
 *
 * @example
 * ```ts
 * source$.pipe(throttleByFrameRate()).subscribe(render);
 * ```
 */
export declare function throttleByFrameRate<T>(): MonoTypeOperatorFunction<T>;
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