85 lines
3 KiB
Markdown
85 lines
3 KiB
Markdown
# desktopCapturer
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> Access information about media sources that can be used to capture audio and
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> video from the desktop using the [`navigator.webkitGetUserMedia`] API.
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The following example shows how to capture video from a desktop window whose
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title is `Electron`:
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```javascript
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// In the renderer process.
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const {desktopCapturer} = require('electron')
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desktopCapturer.getSources({types: ['window', 'screen']}, (error, sources) => {
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if (error) throw error
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for (let i = 0; i < sources.length; ++i) {
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if (sources[i].name === 'Electron') {
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navigator.webkitGetUserMedia({
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audio: false,
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video: {
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mandatory: {
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chromeMediaSource: 'desktop',
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chromeMediaSourceId: sources[i].id,
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minWidth: 1280,
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maxWidth: 1280,
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minHeight: 720,
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maxHeight: 720
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}
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}
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}, handleStream, handleError)
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return
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}
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}
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})
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function handleStream (stream) {
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document.querySelector('video').src = URL.createObjectURL(stream)
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}
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function handleError (e) {
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console.log(e)
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}
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```
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To capture video from a source provided by `desktopCapturer` the constraints
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passed to [`navigator.webkitGetUserMedia`] must include
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`chromeMediaSource: 'desktop'`, and `audio: false`.
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To capture both audio and video from the entire desktop the constraints passed
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to [`navigator.webkitGetUserMedia`] must include `chromeMediaSource: 'screen'`,
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and `audio: true`, but should not include a `chromeMediaSourceId` constraint.
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## Methods
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The `desktopCapturer` module has the following methods:
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### `desktopCapturer.getSources(options, callback)`
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* `options` Object
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* `types` String[] - An array of Strings that lists the types of desktop sources
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to be captured, available types are `screen` and `window`.
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* `thumbnailSize` Object (optional) - The suggested size that the media source
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thumbnail should be scaled to, defaults to `{width: 150, height: 150}`.
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* `callback` Function
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Starts gathering information about all available desktop media sources,
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and calls `callback(error, sources)` when finished.
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`sources` is an array of `Source` objects, each `Source` represents a
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screen or an individual window that can be captured, and has the following
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properties:
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* `id` String - The identifier of a window or screen that can be used as a
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`chromeMediaSourceId` constraint when calling
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[`navigator.webkitGetUserMedia`]. The format of the identifier will be
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`window:XX` or `screen:XX`, where `XX` is a random generated number.
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* `name` String - A screen source will be named either `Entire Screen` or
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`Screen <index>`, while the name of a window source will match the window
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title.
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* `thumbnail` [NativeImage](native-image.md) - A thumbnail image. **Note:**
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There is no guarantee that the size of the thumbnail is the same as the
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`thumnbailSize` specified in the `options` passed to
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`desktopCapturer.getSources`. The actual size depends on the scale of the
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screen or window.
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[`navigator.webkitGetUserMedia`]: https://developer.mozilla.org/en/docs/Web/API/Navigator/getUserMedia
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