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