/**
 * Pure toast motion math — slide in from top-center, hold, slide out.
 * Terminal UIs animate by discrete row steps; ease curves keep it smooth-ish.
 */
/**
 * Minimum toast chip height (pad + one body line + pad).
 * Multi-line wraps use a taller box; pass `boxHeight` into toastAnimAt.
 */
export declare const TOAST_BOX_HEIGHT = 3;
/** Resting top row when fully visible (1 = just under terminal top edge). */
export declare const TOAST_REST_TOP = 1;
/** Off-screen top when fully hidden above the viewport (min height). */
export declare const TOAST_HIDDEN_TOP: number;
export type ToastAnimPhase = "enter" | "hold" | "exit" | "gone";
export interface ToastAnimState {
    readonly phase: ToastAnimPhase;
    /** Absolute top row for absolute positioning. */
    readonly top: number;
    /**
     * 0..1 visibility for optional dimming (1 = fully shown).
     * Terminal cannot fade alpha; host may map low values to DIM.
     */
    readonly visibility: number;
}
/**
 * Compute motion for a toast at `ageMs` since createdAt.
 * @param holdMs time at rest (item.durationMs)
 * @param boxHeight rendered height (pad + wrapped body lines); default min chip
 */
export declare function toastAnimAt(ageMs: number, holdMs: number, boxHeight?: number): ToastAnimState;