import { Observable } from '../../observable';
import { Animation } from '../animation';
import { Keyframe } from '../keyframe';
/**
 * Abstract base class for animation tracks.
 * Tracks are responsible for managing animated properties and responding to time-based updates.
 *
 * @param anim The associated Animation instance.
 * @param id Optional unique identifier for the track.
 */
export declare abstract class Track {
    readonly id?: string | undefined;
    /** @internal */
    influencedPathsDirty: Observable<boolean, never>;
    constructor(anim: Animation, id?: string | undefined);
    /**
     * Abstract getter for the list of paths influenced by the track.
     * Must be implemented by subclasses to return the relevant paths.
     *
     * @returns An array of strings representing the influenced paths.
     */
    abstract get influencedPaths(): string[];
    /**
     * Abstract method to compute the property value for a given path at a specific time.
     * Must be implemented by subclasses to provide the property computation logic.
     *
     * @param t The time at which to compute the property.
     * @param p The path of the property to compute.
     * @param valueBefore The initial value of the property before computation.
     * @param parentWeight Optional weight from the parent track.
     * @returns The computed property value.
     */
    abstract computePathProperty(t: number, p: string, valueBefore: any, parentWeight?: number): any;
    /**
     * Determines if the track is stalled. Default implementation returns false.
     *
     * @returns A boolean indicating if the track is stalled.
     */
    isStalled(): boolean;
}
/**
 * Resolves the interpolated value between two keyframes at a given time.
 *
 * @param t The current time.
 * @param before The keyframe before the current time.
 * @param after The keyframe after the current time, if any.
 * @returns The interpolated value.
 */
export declare function resolveKeyframeValue(t: number, before: Keyframe, after: Keyframe | undefined): any;
/**
 * Finds the keyframes before and after a given time.
 *
 * @param keyframes An array of keyframes.
 * @param t The time for which to find the keyframes.
 * @returns A tuple containing the keyframes before and after the given time.
 */
export declare function resolveKeyframes(keyframes: Keyframe[], t: number): [before: Keyframe | undefined, after: Keyframe | undefined];
/**
 * Resolves the clip time and loop number for a given time within a clip.
 *
 * @param t The current time.
 * @param t0 The start time of the clip.
 * @param s0 The initial state time of the clip.
 * @param rate The rate of playback.
 * @param length The length of the clip.
 * @param timeBackwards A boolean indicating if time is moving backwards.
 * @param t1 Optional end time of the clip.
 * @returns A tuple containing the resolved clip time and loop number.
 */
export declare function resolveClipTimeLoops(t: number, t0: number, s0: number, rate: number, length: number, timeBackwards: boolean, t1?: number): [ct: number, loop: number];