/**
 * QA360 Visual Comparison Module
 *
 * P0 Features: Pixel diff for visual regression testing
 * - Pixel-by-pixel comparison
 * - Perceptual diff with anti-aliasing tolerance
 * - Configurable thresholds
 * - Diff image generation
 */
/**
 * Pixel comparison result
 */
export interface PixelDiffResult {
    /** Whether images are considered identical */
    identical: boolean;
    /** Number of differing pixels */
    diffPixels: number;
    /** Total pixels compared */
    totalPixels: number;
    /** Percentage of difference (0-100) */
    diffPercentage: number;
    /** Path to generated diff image */
    diffImagePath?: string;
}
/**
 * Pixel comparison options
 */
export interface PixelDiffOptions {
    /** Maximum allowed difference percentage (0-100) */
    threshold?: number;
    /** Pixel color difference threshold (0-255) */
    pixelThreshold?: number;
    /** Whether to generate a diff image */
    generateDiffImage?: boolean;
    /** Output directory for diff images */
    outputDir?: string;
    /** Antialiasing tolerance (ignore minor color differences) */
    antialiasing?: boolean;
}
/**
 * Pixel Diff Comparator
 */
export declare class PixelDiff {
    /**
     * Compare two images pixel by pixel
     *
     * @param image1Path - Path to baseline image
     * @param image2Path - Path to current image
     * @param options - Comparison options
     * @returns Comparison result
     */
    static compare(image1Path: string, image2Path: string, options?: PixelDiffOptions): Promise<PixelDiffResult>;
    /**
     * Compare two image buffers directly
     *
     * @param buffer1 - First image buffer (PNG)
     * @param buffer2 - Second image buffer (PNG)
     * @param options - Comparison options
     * @returns Comparison result
     */
    static compareBuffers(buffer1: Buffer, buffer2: Buffer, options?: PixelDiffOptions): Promise<PixelDiffResult>;
    /**
     * Calculate perceptual color difference
     * Uses Euclidean distance in RGB space
     */
    private static colorDifference;
    /**
     * Load image from file path
     */
    private static loadImage;
    /**
     * Decode PNG buffer to image data
     */
    private static decodeBuffer;
    /**
     * Save diff image to file
     */
    private static saveDiffImage;
}
/**
 * Convenience function to compare two images
 */
export declare function compareImages(image1Path: string, image2Path: string, options?: PixelDiffOptions): Promise<PixelDiffResult>;
/**
 * Convenience function to compare two image buffers
 */
export declare function compareImageBuffers(buffer1: Buffer, buffer2: Buffer, options?: PixelDiffOptions): Promise<PixelDiffResult>;