46 lines
1.1 KiB
JavaScript
46 lines
1.1 KiB
JavaScript
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'use strict';
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var util = require('util');
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var Stream = require('stream');
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var constants = require('./constants');
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var Packer = require('./packer');
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var PackerAsync = module.exports = function(opt) {
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Stream.call(this);
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var 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', new Buffer(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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var 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('data', function(compressedData) {
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this.emit('data', this._packer.packIDAT(compressedData));
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}.bind(this));
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this._deflate.on('end', 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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this._deflate.end(filteredData);
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};
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