import type { ElementRect } from "../rect.js";
import type { Effect, EffectContext, EffectDims, EffectRenderTarget } from "../types.js";
import type { TransitionEase, TransitionEffect, TransitionProgress, TransitionRun } from "./types.js";
export type TransitionStartOpts = {
    /** Seconds. Above 0. */
    duration: number;
    /** Defaults to `"smoothstep"`. */
    ease?: TransitionEase;
    /** Called once when this run finishes or is replaced. */
    onEnd?(): void;
};
/** What the transition effects of a run see. Null while idle. */
export type TransitionFrame = {
    from: EffectRenderTarget;
    progress: TransitionProgress;
    /** True while the old content is held, before the animation. */
    holding: boolean;
};
/**
 * First effect of every transition chain. States:
 * - idle: disabled, the chain passes the capture through.
 * - hold: shows the snapshot of the old content while the new one is captured.
 * - playing: disabled, so the live capture goes to the transition effects; it only keeps time.
 */
export declare class TransitionStage implements Effect {
    #private;
    enabled: boolean;
    /** Copy the current capture into `from` on the next frame and hold it on screen. */
    snapshot(): Promise<void>;
    /** Resolves when the transition ends or another one replaces it. */
    start(spec: TransitionStartOpts): Promise<void>;
    /** Stop any transition, drop a pending snapshot and pass the capture through. */
    cancel(): void;
    get frame(): TransitionFrame | null;
    /** End the playing run now; the live capture shows from this frame on. */
    cut(): void;
    update(ctx: EffectContext): void;
    render(ctx: EffectContext): void;
    dispose(): void;
}
export type TransitionFrameSource = {
    readonly frame: TransitionFrame | null;
    cut(): void;
};
/**
 * Puts a `TransitionEffect` in the chain.
 * Skipped outside a run; during one it passes the run state on the context.
 */
export declare class TransitionSlot implements Effect {
    #private;
    readonly effect: TransitionEffect;
    constructor(effect: TransitionEffect, source: TransitionFrameSource);
    get enabled(): boolean;
    start(run: TransitionRun): void;
    end(): void;
    init(ctx: EffectContext): void | Promise<void>;
    update(ctx: EffectContext): void;
    render(ctx: EffectContext): void;
    outputRect(dims: EffectDims): ElementRect | undefined;
    dispose(): void;
}