import { Observable } from '../observable';
import { Animation } from './animation';
import { AnimationState } from './animationstate';
import { Easing } from './bezier';
import { LayerClip, LayerClipPlayOptions } from './layerclip';
/**
 * Defines the parameters for a fade effect.
 *
 * @interface
 * @property time - The duration of the fade effect in seconds.
 * @property pin - Optional. This value (between 0 and 1) indicates if this fade takes place at the beginning (0), middle (0.5) or end (1) of the transition.
 * @property easing - Optional. The easing function to be used for the fade effect.
 * @property reverse - Optional. A boolean indicating if the fade effect should be reversed.
 */
export interface FadeParameters {
    time: number;
    pin?: number;
    easing?: Easing;
    reverse?: boolean;
}
/**
 * Represents a layer within an animation. Manages a collection of LayerClips and their playback within the layer.
 * Supports queuing of clips, computation of path properties, and handling fade parameters.
 */
export declare class Layer {
    readonly animation: Animation;
    readonly scriptName?: string | undefined;
    readonly id?: string | undefined;
    /**
     * Collection of LayerClips indexed by ID.
     */
    clips: {
        [id: string]: LayerClip;
    };
    /**
     *  Optional default fade parameters for the layer.
     */
    defaultFadeParameters?: FadeParameters;
    /**
     * Observable indicating if the influenced paths are dirty.
     */
    influencedPathsDirty: Observable<boolean, never>;
    private _influencedPaths;
    private _active;
    private _queue;
    private _layerClips;
    /**
     * Creates an instance of Layer.
     * @param animation - The animation that the layer belongs to.
     * @param scriptName - Optional. The name of the script that the layer belongs to.
     * @param id - Optional. The ID of the layer.
     */
    constructor(animation: Animation, scriptName?: string | undefined, id?: string | undefined);
    /**
     * Computes the property value for a given path at a specified time.
     * Applies fade parameters and clip-specific computations.
     *
     * @param t The current time.
     * @param p The path of the property to compute.
     * @param valueBefore The initial value of the property before computation.
     * @returns The computed property value.
     */
    computePathProperty(t: number, p: string, valueBefore: any): any;
    /** @internal */
    tick(t: number, touchedPaths: string[]): void;
    /**
     * Pauses the currently active LayerClip, if any.
     */
    pause(): void;
    /** @internal */
    _registerLayerClip(layerClip: LayerClip): void;
    /**
     * Queues a LayerClip for playback with optional play options.
     *
     * @param layerClip The LayerClip to queue.
     * @param playOptions Optional play options for the clip.
     * @returns The created QueueEntry.
     */
    queue(layerClip: LayerClip | null, playOptions?: LayerClipPlayOptions): QueueEntry;
    /**
     * Gets the currently active LayerClip.
     *
     * @returns The active LayerClip, if any.
     */
    get active(): LayerClip | null | undefined;
    /**
     * Sets the active LayerClip for the layer.
     *
     * @param layerClip The LayerClip to set as active.
     */
    set active(layerClip: LayerClip | null | undefined);
    /**
     * Sets the active LayerClip with optional play options.
     *
     * @param layerClip The LayerClip to set as active.
     * @param playOptions Optional play options for the clip.
     */
    setActive(layerClip: LayerClip | null, playOptions?: LayerClipPlayOptions): void;
    /** @internal */
    _activateLayerClip(layerClip: LayerClip | null | undefined, playOptions?: LayerClipPlayOptions): void;
    /** @internal */
    _evaulate(): void;
    private _getTime;
    /** @internal */
    _serialize(state: AnimationState): void;
    /** @internal */
    _restore(state: AnimationState): void;
    /**
     * Gets the set of paths influenced by the layer.
     *
     * @returns A set of strings representing the influenced paths.
     */
    get influencedPaths(): Set<string>;
}
/**
 * Represents an entry in the queue of a Layer, containing a LayerClip and related playback options.
 * @internal
 */
export interface QueueEntry {
    layerClip: LayerClip | null;
    playOptions?: LayerClipPlayOptions;
    fadeByPath: {
        [id: string]: Partial<FadeParameters>;
    };
    fadeTime: number;
    startTime?: number;
}