MediaTrackSupportedConstraints.logicalSurface - Web APIs 编辑

The MediaTrackSupportedConstraints dictionary's logicalSurface property indicates whether or not the logicalSurface constraint is supported by the user agent and the device on which the content is being used.

The supported constraints list is obtained by calling navigator.mediaDevices.getSupportedConstraints().

Syntax

isLogicalSurfaceSupported = supportedConstraints.logicalSurface;

Value

A Boolean value which is true if the logicalSurface constraint is supported by the device and user agent.

Example

This method sets up the constraints object specifying the options for the call to getDisplayMedia(). It adds the logicalSurface constraint (requesting that only logical display surfaces—those which may not be entirely visible onscreen—be included among the options available to the user) only if it is known to be supported by the browser. Capturing is then started by calling getDisplayMedia() and attaching the returned stream to the video element referenced by the variable videoElem.

async function capture() {
  let supportedConstraints = navigator.mediaDevices.getSupportedConstraints();
  let displayMediaOptions = {
    video: {
    },
    audio: false;
  };

  if (supportedConstraints.logicalSurface) {
    displayMediaOptions.video.logicalSurface = "monitor";
  }

  try {
    videoElem.srcObject = await navigator.mediaDevices.getDisplayMedia(displayMediaOptions);
  } catch(err) {
    /* handle the error */
  }
}

Specifications

Browser compatibility

BCD tables only load in the browser

See also

• Screen Capture API
• Using the screen capture API
• Capabilities, constraints, and settings
• MediaDevices.getDisplayMedia()
• MediaStreamTrack.getConstraints()
• MediaStreamTrack.applyConstraints()
• MediaStreamTrack.getSettings()