import type { AnimStyle } from './animation.js';
import { type MediaClip, type TextClipStyle, type TimelineAspectRatio, type TimelineClip, type TimelineProject, type TimelineTrack } from '../types/timeline.js';
/** Inline-style object with camelCase CSS property names — usable as a React
 * `style` prop, with `Object.assign(el.style, …)`, or via `toCssText`. */
export type CssProperties = Record<string, string | number>;
/** Project length in frames: the end of the last clip (0 when empty). */
export declare function projectDurationF(project: TimelineProject): number;
/** Whether the clip is on screen/audible at `t` seconds: `[start, end)`. */
export declare function isClipActive(clip: TimelineClip, t: number, fps: number): boolean;
/** Position inside the clip's SOURCE media (seconds) for timeline time `t`. */
export declare function clipSourceSec(clip: MediaClip, t: number, fps: number): number;
/** All clips on visible tracks, bottom → top. Track array order is z-order
 * (index 0 = bottom); `zIndex` is that track index. Hidden tracks are skipped. */
export declare function layeredClips(project: TimelineProject): {
    clip: TimelineClip;
    zIndex: number;
}[];
/** The clips visible at `t` seconds, bottom → top. */
export declare function visibleClipsAt(project: TimelineProject, t: number): {
    clip: TimelineClip;
    zIndex: number;
}[];
/** Width / height, e.g. `'16:9'` → 1.777… */
export declare function aspectRatioValue(aspectRatio: TimelineAspectRatio): number;
/** Largest stage that fits `containerWidth × containerHeight` at the aspect ratio. */
export declare function fitStage(aspectRatio: TimelineAspectRatio, containerWidth: number, containerHeight: number): {
    width: number;
    height: number;
};
/** Output pixel size whose SHORT side is `shortSide` (16:9 → 1920×1080 by default). */
export declare function compositionSize(aspectRatio: TimelineAspectRatio, shortSide?: number): {
    width: number;
    height: number;
};
/** Track audibility: any solo → only soloed tracks play; mute always silences
 * its own track, even when soloed. */
export declare function trackAudible(project: TimelineProject, track: TimelineTrack | undefined): boolean;
/** Whether the clip should be heard at all (track mute/solo, detached audio,
 * zero volume). Timing is separate — see `isClipActive`. */
export declare function clipAudible(project: TimelineProject, clip: TimelineClip): boolean;
/** Output gain in [0,1] at `t` seconds: clip volume × linear fade-in/out ramps
 * relative to the clip edges. Does not apply mute/solo — see `clipAudible`. */
export declare function clipGain(clip: MediaClip, t: number, fps: number): number;
/** `#rrggbb` + opacity → `rgba(r, g, b, a)`. */
export declare function hexToRgba(hex: string, opacity: number): string;
/** Full-bleed media layer (video/image): covers the stage, plus the clip's
 * enter/exit animation when `anim` is given. */
export declare function mediaClipCss(anim?: AnimStyle): CssProperties;
/**
 * A text clip's box, positioned inside a stage of `stageHeight` px (the stage
 * itself must be `position: relative`). All sizes are % of stage height, so the
 * result scales to any output resolution. Pass the clip's `clipAnimStyle` as
 * `anim` to include its enter/exit animation.
 */
export declare function textClipCss(style: TextClipStyle, stageHeight: number, anim?: AnimStyle): CssProperties;
/** Serialize a `CssProperties` object to an inline `style` string. */
export declare function toCssText(css: CssProperties): string;