import type { ChapterCameraKeyframe, ChapterCameraTrack } from '../core/types/story';
import type { ViewBox } from '../core/types/viewer';
export type CameraTrackSample = Pick<ChapterCameraKeyframe, 'viewBox' | 'model' | 'layerOpacities'>;
export declare const retimeCameraKeyframes: (keyframes: ChapterCameraKeyframe[], durationMs: number) => ChapterCameraKeyframe[];
export declare const catmullRom: (p0: number, p1: number, p2: number, p3: number, t: number) => number;
export declare const generateCameraPreset: (preset: NonNullable<ChapterCameraTrack["preset"]>, viewBox: ViewBox, durationMs?: number, initialDwellMs?: number) => ChapterCameraTrack;
/**
 * How long a track actually animates for, which is what a chapter's length
 * should be measured against.
 *
 * A track needs two keyframes to move between — the motion editor says as much
 * before it enables its controls. Opening the motion tools and setting a
 * duration without placing points leaves a track that animates nothing, and
 * counting its duration held chapters on screen long after their narration had
 * finished, with no camera movement to show for it.
 */
export declare const animatableCameraDurationMs: (track: ChapterCameraTrack | undefined) => number;
export declare const configureCameraTrackPreset: (track: ChapterCameraTrack | undefined, preset: NonNullable<ChapterCameraTrack["preset"]>, currentView: ViewBox, durationMs?: number, options?: {
    preservePoints?: boolean;
}) => ChapterCameraTrack;
/**
 * Returns authored points on the exact clock playback will use. Dwell is
 * added before movement and every movement leg receives an equal share of the
 * duration, so deleting, replacing, or moving a point cannot unpredictably
 * reshuffle all of the other timestamps.
 */
export declare const balanceCameraTrackKeyframes: (track: ChapterCameraTrack) => ChapterCameraKeyframe[];
/**
 * Deterministically samples an in-chapter camera path at a presentation time.
 *
 * Motion-point timing is automatic in the authoring UI. Playback adds all
 * dwell time before movement, then divides the movement duration equally
 * between legs. This keeps the timeline predictable and ensures a hold can
 * never overlap a later point's displayed arrival time.
 */
export declare const sampleCameraTrack: (track: ChapterCameraTrack, timeMs: number) => CameraTrackSample | null;