/// <reference types="node" />
import png = require("./index");
import ChunkStream = require("./chunk-stream");
export = Filter;
declare class Filter extends ChunkStream {
    private _width;
    private _height;
    private _bpp;
    private _data;
    private _option;
    private _line;
    private _filterTypes;
    private _filters;
    constructor(width: number, height: number, bpp: number, data: Buffer, option: png.IImageOptions);
    filter(): Buffer;
    private _reverseFilterLine;
    private _filterNone;
    private _filterSub;
    private _filterUp;
    private _filterAvg;
    private _filterPaeth;
}
