import type { PrototypeEasing } from './prototype.js';
import type { PrototypeMotionSample, PrototypeSpringParameters } from './prototypeMotionContracts.js';
export interface PrototypeSpringPlan {
    readonly from: number;
    readonly to: number;
    /** Absolute progress units per second, including when to < from. */
    readonly initialVelocity: number;
    readonly parameters: Readonly<PrototypeSpringParameters>;
    readonly maxDurationMs: number;
    readonly durationMs: number;
    readonly reason: 'settled' | 'duration-cap';
}
export interface CreatePrototypeSpringPlanOptions {
    parameters: PrototypeSpringParameters;
    from?: number;
    to?: number;
    initialVelocity?: number;
    /** Maximum physical time, bounded to ten seconds; never a trajectory scaling factor. */
    durationMs: number;
}
export declare function resolvePrototypeSpringParameters(easing: Extract<PrototypeEasing, {
    type: 'spring';
}>): PrototypeSpringParameters;
export declare function createPrototypeSpringPlan(input: CreatePrototypeSpringPlanOptions): PrototypeSpringPlan;
export declare function samplePrototypeSpring(plan: PrototypeSpringPlan, elapsedMs: number): PrototypeMotionSample;
/** Bounded piecewise-linear CSS approximation of physical samples, including overshoot and truncated endpoints.
 * The last value is never forced to one. Equal endpoints with nonzero velocity need actual sampled keyframes. */
export declare function prototypeSpringEasingCss(plan: PrototypeSpringPlan, sampleCount?: number): string;