42 lines
874 B
JavaScript
42 lines
874 B
JavaScript
|
'use strict'
|
||
|
|
|
||
|
|
/*!
|
||
|
|
* Canvas - JPEGStream
|
||
|
|
* Copyright (c) 2010 LearnBoost <tj@learnboost.com>
|
||
|
|
* MIT Licensed
|
||
|
|
*/
|
||
|
|
|
||
|
|
const { Readable } = require('stream')
|
||
|
|
function noop () {}
|
||
|
|
|
||
|
|
class JPEGStream extends Readable {
|
||
|
|
constructor (canvas, options) {
|
||
|
|
super()
|
||
|
|
|
||
|
|
if (canvas.streamJPEGSync === undefined) {
|
||
|
|
throw new Error('node-canvas was built without JPEG support.')
|
||
|
|
}
|
||
|
|
|
||
|
|
this.options = options
|
||
|
|
this.canvas = canvas
|
||
|
|
}
|
||
|
|
|
||
|
|
_read () {
|
||
|
|
// For now we're not controlling the c++ code's data emission, so we only
|
||
|
|
// call canvas.streamJPEGSync once and let it emit data at will.
|
||
|
|
this._read = noop
|
||
|
|
|
||
|
|
this.canvas.streamJPEGSync(this.options, (err, chunk) => {
|
||
|
|
if (err) {
|
||
|
|
this.emit('error', err)
|
||
|
|
} else if (chunk) {
|
||
|
|
this.push(chunk)
|
||
|
|
} else {
|
||
|
|
this.push(null)
|
||
|
|
}
|
||
|
|
})
|
||
|
|
}
|
||
|
|
};
|
||
|
|
|
||
|
|
module.exports = JPEGStream
|