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46 lines
1.1 KiB
46 lines
1.1 KiB
4 years ago
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'use strict';
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/*!
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* Canvas - JPEGStream
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* Copyright (c) 2010 LearnBoost <tj@learnboost.com>
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* MIT Licensed
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*/
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var Readable = require('stream').Readable;
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var util = require('util');
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var JPEGStream = module.exports = function JPEGStream(canvas, options) {
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if (!(this instanceof JPEGStream)) {
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throw new TypeError("Class constructors cannot be invoked without 'new'");
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}
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if (canvas.streamJPEGSync === undefined) {
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throw new Error("node-canvas was built without JPEG support.");
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}
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Readable.call(this);
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this.options = options;
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this.canvas = canvas;
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};
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util.inherits(JPEGStream, Readable);
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function noop() {}
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JPEGStream.prototype._read = function _read() {
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// For now we're not controlling the c++ code's data emission, so we only
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// call canvas.streamJPEGSync once and let it emit data at will.
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this._read = noop;
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var self = this;
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self.canvas.streamJPEGSync(this.options, function(err, chunk){
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if (err) {
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self.emit('error', err);
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} else if (chunk) {
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self.push(chunk);
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} else {
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self.push(null);
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}
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});
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};
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