/**
 * Bitmap blur filters - Gaussian and Box blur
 */
import { type Bitmap } from "./types.ts";
/**
 * Generate 1D Gaussian kernel
 * Uses Gaussian function: exp(-x²/(2σ²))
 *
 * @param radius Blur radius (sigma value)
 * @returns Normalized Gaussian kernel weights
 */
export declare function createGaussianKernel(radius: number): Float32Array;
/**
 * Gaussian blur implementation using separable 2-pass algorithm
 * Modifies bitmap in-place and returns it
 *
 * @param bitmap Bitmap to blur (modified in-place)
 * @param radius Blur radius in pixels
 * @returns The same bitmap after blur is applied
 */
export declare function gaussianBlur(bitmap: Bitmap, radius: number): Bitmap;
/**
 * Box blur using running sum for O(1) per pixel
 * Modifies bitmap in-place and returns it
 *
 * @param bitmap Bitmap to blur (modified in-place)
 * @param radius Blur radius in pixels
 * @returns The same bitmap after blur is applied
 */
export declare function boxBlur(bitmap: Bitmap, radius: number): Bitmap;
/**
 * Apply blur filter to a bitmap in-place
 * @param bitmap - Bitmap to blur (modified in-place)
 * @param radius - Blur radius in pixels (can be fractional)
 * @param type - Blur type: 'gaussian' (default) or 'box'
 * @returns The modified bitmap
 */
export declare function blurBitmap(bitmap: Bitmap, radius: number, type?: "gaussian" | "box"): Bitmap;