"use strict"; let util = require("util"); let Stream = require("stream"); let constants = require("./constants"); let Packer = require("./packer"); let PackerAsync = (module.exports = function (opt) { Stream.call(this); let options = opt || {}; this._packer = new Packer(options); this._deflate = this._packer.createDeflate(); this.readable = true; }); util.inherits(PackerAsync, Stream); PackerAsync.prototype.pack = function (data, width, height, gamma) { // Signature this.emit("data", Buffer.from(constants.PNG_SIGNATURE)); this.emit("data", this._packer.packIHDR(width, height)); if (gamma) { this.emit("data", this._packer.packGAMA(gamma)); } let filteredData = this._packer.filterData(data, width, height); // compress it this._deflate.on("error", this.emit.bind(this, "error")); this._deflate.on( "data", function (compressedData) { this.emit("data", this._packer.packIDAT(compressedData)); }.bind(this) ); this._deflate.on( "end", function () { this.emit("data", this._packer.packIEND()); this.emit("end"); }.bind(this) ); this._deflate.end(filteredData); };