/**
 * Dependency-free contract for image optimization engines.
 *
 * Core owns filesystem access, publication, request/result validation, and
 * resource limits. Extensions own decoding, resizing, and encoding.
 *
 * @module extensions/image/image-optimization-engine
 */
/** Registry name used for the image optimization extension contract. */
export declare const ImageOptimizationEngineName: "ImageOptimizationEngine";
/** Maximum stable implementation identity accepted across the boundary. */
export declare const MAX_IMAGE_OPTIMIZATION_ENGINE_IDENTITY_CHARACTERS: 256;
/** Formats core can request from an image optimization engine. */
export type ImageOptimizationFormat = "webp" | "avif" | "jpeg" | "png";
/** Immutable byte-oriented request supplied by core. */
export interface ImageOptimizationRequest {
    readonly input: Uint8Array;
    /**
     * Configured target widths. The engine returns each distinct width that does
     * not exceed the decoded source width, plus the source width itself.
     */
    readonly targetWidths: readonly number[];
    /** Every format to produce for each resulting width. */
    readonly formats: readonly ImageOptimizationFormat[];
    /** Encoding quality applied consistently across requested formats. */
    readonly quality: number;
    /** Aborted when the caller cancels or the core operation deadline expires. */
    readonly signal: AbortSignal;
}
/** One encoded output returned by an image optimization engine. */
export interface ImageOptimizationVariantResult {
    readonly format: ImageOptimizationFormat;
    readonly width: number;
    readonly height: number;
    readonly data: Uint8Array;
}
/** Portable result returned by an image optimization engine. */
export interface ImageOptimizationResult {
    readonly sourceWidth: number;
    readonly sourceHeight: number;
    readonly variants: readonly ImageOptimizationVariantResult[];
}
/**
 * Image decoder, resizer, and encoder implemented by an explicit extension.
 *
 * Implementations are long-lived, concurrency-safe services. They must not
 * require caller-managed lifecycle cleanup and must release operation-scoped
 * resources when the Promise returned by `optimize()` settles. Core may stop
 * awaiting an operation after aborting its signal, so a late result must not
 * rely on caller publication or cleanup behavior.
 */
export interface ImageOptimizationEngine {
    /**
     * Includes every implementation/version input capable of changing output.
     * Represented state must remain immutable for the captured engine lifetime.
     */
    readonly cacheIdentity: string;
    optimize(request: ImageOptimizationRequest): Promise<ImageOptimizationResult>;
}
/** Validate an implementation received through the dynamic contract registry. */
export declare function assertImageOptimizationEngine(value: unknown): asserts value is ImageOptimizationEngine;
/** Capture dynamic properties once so one run cannot split across mutations. */
export declare function captureImageOptimizationEngine(value: unknown): ImageOptimizationEngine;
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