electron/docs/api/desktop-capturer.md
Kevin Sawicki 4f99cb19bd 🔥 ;
2017-05-15 13:38:57 -07:00

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# desktopCapturer
> Access information about media sources that can be used to capture audio and
> video from the desktop using the [`navigator.mediaDevices.getUserMedia`] API.
Process: [Renderer](../glossary.md#renderer-process)
The following example shows how to capture video from a desktop window whose
title is `Electron`:
```javascript
// In the renderer process.
const {desktopCapturer} = require('electron')
desktopCapturer.getSources({types: ['window', 'screen']}, (error, sources) => {
if (error) throw error
for (let i = 0; i < sources.length; ++i) {
if (sources[i].name === 'Electron') {
navigator.mediaDevices.getUserMedia({
audio: false,
video: {
mandatory: {
chromeMediaSource: 'desktop',
chromeMediaSourceId: sources[i].id,
minWidth: 1280,
maxWidth: 1280,
minHeight: 720,
maxHeight: 720
}
}
}, handleStream, handleError)
return
}
}
})
function handleStream (stream) {
document.querySelector('video').src = URL.createObjectURL(stream)
}
function handleError (e) {
console.log(e)
}
```
To capture video from a source provided by `desktopCapturer` the constraints
passed to [`navigator.mediaDevices.getUserMedia`] must include
`chromeMediaSource: 'desktop'`, and `audio: false`.
To capture both audio and video from the entire desktop the constraints passed
to [`navigator.mediaDevices.getUserMedia`] must include `chromeMediaSource: 'desktop'`,
for both `audio` and `video`, but should not include a `chromeMediaSourceId` constraint.
```javascript
const constraints = {
audio: {
mandatory: {
chromeMediaSource: 'desktop'
}
},
video: {
mandatory: {
chromeMediaSource: 'desktop'
}
}
}
```
## Methods
The `desktopCapturer` module has the following methods:
### `desktopCapturer.getSources(options, callback)`
* `options` Object
* `types` String[] - An array of Strings that lists the types of desktop sources
to be captured, available types are `screen` and `window`.
* `thumbnailSize` [Size](structures/size.md) (optional) - The size that the media source thumbnail
should be scaled to. Default is `150` x `150`.
* `callback` Function
* `error` Error
* `sources` [DesktopCapturerSource[]](structures/desktop-capturer-source.md)
Starts gathering information about all available desktop media sources,
and calls `callback(error, sources)` when finished.
`sources` is an array of [`DesktopCapturerSource`](structures/desktop-capturer-source.md)
objects, each `DesktopCapturerSource` represents a screen or an individual window that can be
captured.
[`navigator.mediaDevices.getUserMedia`]: https://developer.mozilla.org/en/docs/Web/API/MediaDevices/getUserMedia