desktopCapturer

访问关于使用navigator.mediaDevices.getUserMedia API 获取的可以用来从桌面捕获音频和视频的媒体源的信息。

Process: Main

下面的示例演示如何从标题为 Electron 的桌面窗口捕获视频:

// main.js
const { app, BrowserWindow, desktopCapturer, session } = require('electron')

app.whenReady().then(() => {
  const mainWindow = new BrowserWindow()

  session.defaultSession.setDisplayMediaRequestHandler((request, callback) => {
    desktopCapturer.getSources({ types: ['screen'] }).then((sources) => {
      // Grant access to the first screen found.
      callback({ video: sources[0], audio: 'loopback' })
    })
    // If true, use the system picker if available.
    // Note: this is currently experimental. If the system picker
    // is available, it will be used and the media request handler
    // will not be invoked.
  }, { useSystemPicker: true })

  mainWindow.loadFile('index.html')
})

// renderer.js
const startButton = document.getElementById('startButton')
const stopButton = document.getElementById('stopButton')
const video = document.querySelector('video')

startButton.addEventListener('click', () => {
  navigator.mediaDevices.getDisplayMedia({
    audio: true,
    video: {
      width: 320,
      height: 240,
      frameRate: 30
    }
  }).then(stream => {
    video.srcObject = stream
    video.onloadedmetadata = (e) => video.play()
  }).catch(e => console.log(e))
})

stopButton.addEventListener('click', () => {
  video.pause()
})

<!-- index.html -->
<html>
<meta http-equiv="content-security-policy" content="script-src 'self' 'unsafe-inline'" />
  <body>
    <button id="startButton" class="button">Start</button>
    <button id="stopButton" class="button">Stop</button>
    <video width="320" height="240" autoplay></video>
    <script src="renderer.js"></script>
  </body>
</html>

See navigator.mediaDevices.getDisplayMedia for more information.

Note: navigator.mediaDevices.getDisplayMedia does not permit the use of deviceId for selection of a source - see specification.

方法

desktopCapturer 模块有以下方法:

`desktopCapturer.getSources(options)`

选项 对象
- types string[] - An array of strings that lists the types of desktop sources to be captured, available types can be screen and window.
- thumbnailSize Size (optional) - The size that the media source thumbnail should be scaled to. 默认是 150 x 150。当您不需要缩略图时，设置宽度或高度为0。这将节省用于获取每个窗口和屏幕内容时的处理时间。
- fetchWindowIcons boolean (可选) - 设置为 true 以启用提取窗口图标。默认值为false。当值为false时，源的appIcon属性返回null。如果一个源是屏幕类型也是如此。

Returns Promise<DesktopCapturerSource[]> - Resolves with an array of DesktopCapturerSource objects, each DesktopCapturerSource represents a screen or an individual window that can be captured.

Note Capturing the screen contents requires user consent on macOS 10.15 Catalina or higher, which can detected by systemPreferences.getMediaAccessStatus.

注意事项

由于存在基本限制，因此navigator.mediaDevices.getUserMedia 无法在macOS上进行音频捕获，因此要访问系统音频的应用程序需要一个签名内核拓展. Chromium以及Electron扩展不提供这个。

通过使用另一个MacOS应用程序（如Soundflower）捕获系统音频并将其通过虚拟音频输入设备来规避此限制是可能的。然后可以用 navigator.mediaDevices.getUserMedia查询该虚拟设备。

方法​

desktopCapturer.getSources(options)​

注意事项​

方法

`desktopCapturer.getSources(options)`

注意事项