/// <reference types="node" />
export interface DiffPassingResult {
    matches: true;
}
export interface DiffFailingResult {
    matches: false;
    /**
     * A PNG MIME encoded buffer of the diff image.
     */
    diff: Buffer;
    /**
     * The difference in percentage points (0-100).
     */
    percentage: number;
}
/**
 * A discriminated union of a passing result and a failing result.
 *
 * Check the `matches` property before attempting to access the `diff`.
 */
export declare type DiffResult = DiffPassingResult | DiffFailingResult;
/**
 * Compare two screenshots and produce a diff image if necessary.
 */
export interface PNGDiffer {
    /**
     * @param expected PNG encoded buffer.
     * @param actual PNG encoded buffer.
     */
    compare: (expected: Buffer, actual: Buffer) => Promise<DiffResult>;
}