MediaTrackConstraints.cursor
The MediaTrackConstraints
dictionary's
cursor
property is a ConstrainDOMString
describing the requested or mandatory constraints placed upon the value of the
cursor
constrainable property, which is used
to specify whether or not the cursor should be included in the captured video.
If needed, you can determine whether or not this constraint is supported by checking
the value of MediaTrackSupportedConstraints.cursor
as returned by a call
to MediaDevices.getSupportedConstraints()
. However, typically this is
unnecessary since browsers will ignore any constraints they're unfamiliar with.
Value
A ConstrainDOMString
which specifies whether or not the mouse cursor
should be rendered into the video track in the MediaStream
returned by
the call to getDisplayMedia()
. See
How constraints
are defined in Capabilities, constraints, and settings for an explanation of how to define constraints.
Usage notes
You can check the setting selected by the user agent after the display media has been
created by getDisplayMedia()
by calling
getSettings()
on the display media's
video MediaStreamTrack
, then checking the value of the returned
MediaTrackSettings
object's cursor
object.
For example, if your app needs to alter the stream by inserting a representation of the cursor position if the stream doesn't include the rendered cursor, you can determine the need to do so by using code like this:
let insertFakeCursorFlag = false;
if (displayStream.getVideoTracks()[0].getSettings().cursor === "never") {
insertFakeCursorFlag = true;
}
Following this code, insertFakeCursorFlag
is true
if there's
no cursor rendered into the stream already. Later code can detect this flag's value and
if it's true
, can manually look at some metadata that might be provided and
insert a fake representation of the cursor at the correct position.
Examples
Here are some example constraints objects for getDisplayMedia()
that make
use of the cursor
property. In addition, see
Example:
Constraint exerciser in Capabilities, constraints, and settings for a complete example showing how constraints are used.
Example: Cursor always visible
This example sets up the constraints to request that the cursor always be visible.
let displayMediaOptions = {
cursor: "always"
};
Example: Cursor visible during motion with fallback
In this example, the cursor
property is configured to request that the
cursor be visible when in motion, falling back to always being visible if the user agent
doesn't support in-motion only cursor rendering.
let displayMediaOptions = {
cursor: ["motion", "always"]
};
Example: Require that the cursor not be visible
This constraints object explicitly requires that the cursor not be rendered into the video track.
let displayMediaOptions = {
cursor: {
exact: "none"
}
};
Specifications
Specification |
---|
Screen Capture # dom-mediatrackconstraintset-cursor |
Browser compatibility
BCD tables only load in the browser