MediaTrackConstraints.displaySurface

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句法
用法注意事项
范例
规范
浏览器兼容性
另请参阅
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MediaTrackConstraints dictionary's displaySurface 特性为 ConstrainDOMString describing the requested or mandatory constraints placed upon the value of the displaySurface constrainable property. This is used to specify the type or types of display surfaces which getDisplayMedia() will let the user select among for sharing purposes.

If needed, you can determine whether or not this constraint is supported by checking the value of MediaTrackSupportedConstraints.displaySurface as returned by a call to MediaDevices.getSupportedConstraints() . However, typically this is unnecessary since browsers will simply ignore any constraints they're unfamiliar with.

句法

var constraintsObject = { displaySurface: constraint };
constraintsObject.displaySurface = constraint;

值

A ConstrainDOMString which specifies the type of display surface that's being captured. This value does not affect the list of display sources in the browser's user interface.

见 How constraints are defined in Capabilities, constraints, and settings for an explanation of how to define constraints.

用法注意事项

You can check the setting selected by the user agent after the display media has been created by getDisplayMedia() 通过调用 getSettings() on the display media's video MediaStreamTrack , then checking the value of the returned MediaTrackSettings 对象的 displaySurface 对象。

For example, if your app needs to know that the surface being shared is a monitor or application—meaning that there's possibly a non-content backdrop—it can use code similar to this:

let mayHaveBackdropFlag = false;
let displaySurface = displayStream.getVideoTracks()[0].getSettings().displaySurface;
if (displaySurface === "monitor" || displaySurface ==="application") {
  mayHaveBackdropFlag = true;
}

Following this code, mayHaveBackdrop is true if the display surface contained in the stream is of type monitor or application ; either of these may have non-content backdrop areas. Later code can use this flag to determine whether or not to perform special processing, such as to remove or replace the backdrop, or to "cut" the individual display areas out of the received frames of video.

范例

Here are some example constraints objects for getDisplayMedia() that make use of the displaySurface property. In addition, see Example: Constraint exerciser in Capabilities, constraints, and settings for a complete example showing how constraints are used.

TBD

规范

规范	状态	注释
Screen Capture The definition of 'MediaTrackConstraints.displaySurface' in that specification.	未知	最初的规范。

浏览器兼容性

The compatibility table on this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request. 更新 GitHub 上的兼容性数据

	桌面						移动
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`displaySurface`	Chrome No	Edge No	Firefox No	IE No	Opera Yes	Safari ?	WebView Android No	Chrome Android No	Firefox Android No	Opera Android ?	Safari iOS ?	Samsung Internet Android No

图例

完整支持
不支持
兼容性未知 ?

另请参阅

元数据

最后修改： 2020 年 1 月 22 日

Media Streams API
MediaTrackConstraints
特性
1. aspectRatio
2. autoGainControl
3. channelCount
4. cursor
5. deviceId
6. displaySurface
7. echoCancellation
8. facingMode
9. frameRate
10. groupId
11. height
12. latency
13. logicalSurface
14. noiseSuppression
15. sampleRate
16. sampleSize
17. volume
18. width
Related pages for Media Capture and Streams

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句法

值

用法注意事项

范例

规范

浏览器兼容性

图例

另请参阅

相关话题