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• 句法
• 用法注意事项
• 规范
• 浏览器兼容性
• 另请参阅
• 相关话题

MediaTrackConstraints dictionary's logicalSurface 特性为 ConstrainDOMString describing the requested or mandatory constraints placed upon the value of the logicalSurface constrainable property. This is used to specify whether or not getDisplayMedia() should allow the user to choose display surfaces which are not necessarily fully visible on the screen, such as occluded windows or the complete content of windows which are large enough to require scrolling to see their entire contents.

If needed, you can determine whether or not this constraint is supported by checking the value of MediaTrackSupportedConstraints.logicalSurface 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 = { logicalSurface: constraint };
constraintsObject.logicalSurface = constraint;
					

值

A ConstrainBoolean which is true if logical surfaces should be permitted among the selections available to the user.

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 logicalSurface 对象。

For example, if your app needs to know if the selected display surface is a logical one:

let isLogicalSurface = displayStream.getVideoTracks()[0].getSettings().logicalSurface;
					

Following this code, isLogicalSurface is true if the display surface contained in the stream is a logical surface; that is, one which may not be entirely onscreen, or may even be entirely offscreen.

规范

规范	状态	注释
Screen Capture The definition of 'MediaTrackConstraints.logicalSurface' in that specification.	工作草案	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
logicalSurface	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

完整支持

不支持

不支持

兼容性未知 ?

兼容性未知

另请参阅

• Screen Capture API
• Using the Screen Capture API
• Capabilities, constraints, and settings
• MediaTrackConstraints
• MediaDevices.getSupportedConstraints()
• MediaTrackSupportedConstraints

元数据

• 最后修改： Dec 23, 2019

相关话题

1. Media Streams API
2. MediaTrackConstraints
3. 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
4. Related pages for Media Capture and Streams

   1. AudioStreamTrack
   2. BlobEvent
   3. CanvasCaptureMediaStream
   4. ConstrainBoolean
   5. ConstrainDOMString
   6. ConstrainDouble
   7. ConstrainLong
   8. DoubleRange
   9. HTMLCanvasElement.captureStream()
   10. LongRange
   11. MediaDevices
   12. MediaStream
   13. MediaStreamTrack
   14. MediaStreamTrackEvent
   15. MediaTrackCapabilities
   16. MediaTrackSettings
   17. MediaTrackSupportedConstraints
   18. Navigator.mediaDevices
   19. NavigatorUserMedia
   20. NavigatorUserMediaError
   21. VideoStreamTrack
   22. navigator.mediaDevices.getUserMedia()