import { ImageDataLike, KernelSize, OutputFormat } from './types.js';
/**
 * Converts ImageData to grayscale, applies Sobel kernels, returns new ImageData
 *
 * This class performs edge detection using the Sobel operator.
 * It processes a given ImageData object to extract horizontal and vertical gradients,
 * then outputs a new ImageData with edge intensities encoded as grayscale values.
 *
 * This is a TypeScript implementation with enhancements including:
 * - Variable kernel sizes (3x3, 5x5)
 * - Multiple output formats (magnitude, x, y, direction)
 *
 * Current Maintainer/Developer: @catorch
 *
 * This work builds upon the original JavaScript version by Miguel Mota
 * (https://github.com/miguelmota/sobel, MIT License).
 *
 */
export declare class Sobel {
    private imageData;
    private width;
    private height;
    private grayscaleData;
    private static imageDataFactory;
    private kernelSize;
    private static kernelX3;
    private static kernelY3;
    private static kernelX5;
    private static kernelY5;
    /**
     * Constructor stores image dimensions, kernel size, and computes grayscale version
     * @param imageData - original image data (browser ImageData or Node.js buffer)
     * @param kernelSize - size of the Sobel kernel (3 or 5, defaults to 3)
     */
    constructor(imageData: ImageDataLike, kernelSize?: KernelSize);
    /**
     * Safely retrieves the value of a specific pixel channel in an image array
     * @param data - image pixel array
     * @param x - horizontal coordinate
     * @param y - vertical coordinate
     * @param channel - 0=R, 1=G, 2=B, 3=A (default 0)
     * @returns pixel channel value (0 if out of bounds)
     */
    private pixelAt;
    /**
     * Converts RGBA input to grayscale (preserves alpha as 255)
     * @param imageData - original image data
     * @returns new Uint8ClampedArray of grayscale RGBA pixels
     */
    private convertToGrayscale;
    /**
     * Applies Sobel filter using the specified kernel size and output format
     * @param format - Output format ('magnitude', 'x', 'y', or 'direction')
     * @returns ImageData with edge intensities
     */
    apply(format?: OutputFormat): ImageDataLike;
}