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62 lines
1.3 KiB
62 lines
1.3 KiB
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/*!
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* Canvas - PNGStream
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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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/**
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* Module dependencies.
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*/
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var EventEmitter = require('events').EventEmitter;
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/**
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* Initialize a `PNGStream` with the given `canvas`.
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*
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* "data" events are emitted with `Buffer` chunks, once complete the
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* "end" event is emitted. The following example will stream to a file
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* named "./my.png".
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*
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* var out = fs.createWriteStream(__dirname + '/my.png')
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* , stream = canvas.createPNGStream();
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*
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* stream.on('data', function(chunk){
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* out.write(chunk);
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* });
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*
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* stream.on('end', function(){
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* out.end();
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* });
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*
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* @param {Canvas} canvas
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* @param {Boolean} sync
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* @api public
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*/
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var PNGStream = module.exports = function PNGStream(canvas, sync) {
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var self = this
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, method = sync
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? 'streamPNGSync'
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: 'streamPNG';
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this.sync = sync;
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this.canvas = canvas;
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if ('streamPNG' == method) throw new Error('async png streaming not yet implemented');
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process.nextTick(function(){
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canvas[method](function(err, chunk, len){
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if (err) {
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self.emit('error', err);
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} else if (len) {
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self.emit('data', chunk, len);
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} else {
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self.emit('end');
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}
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});
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});
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};
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/**
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* Inherit from `EventEmitter`.
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*/
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PNGStream.prototype.__proto__ = EventEmitter.prototype;
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