# GestureRecognizerLiveStreamDelegate

    protocol GestureRecognizerLiveStreamDelegate: NSObjectProtocol

This protocol defines an interface for the delegates of `GestureRecognizer` object to receive results of performing asynchronous gesture recognition on images (i.e, when `runningMode` = `.liveStream`).

The delegate of `GestureRecognizer` must adopt `GestureRecognizerLiveStreamDelegate` protocol. The methods in this protocol are optional.
- `
  ### [gestureRecognizer(_:didFinishGestureRecognition:timestampInMilliseconds:error:)](https://developers.google.com/edge/api/mediapipe/swift/vision/Protocols/GestureRecognizerLiveStreamDelegate.md.txt#/c:objc(pl)MPPGestureRecognizerLiveStreamDelegate(im)gestureRecognizer:didFinishRecognitionWithResult:timestampInMilliseconds:error:)

  ` This method notifies a delegate that the results of asynchronous gesture recognition of an image submitted to the `GestureRecognizer` is available.

  This method is called on a private serial dispatch queue created by the `GestureRecognizer` for performing the asynchronous delegates calls.

  #### Declaration

  Swift

      optional func gestureRecognizer(_ gestureRecognizer: GestureRecognizer, didFinishGestureRecognition result: GestureRecognizerResult?, timestampInMilliseconds: Int, error: (any Error)?)

  #### Parameters

  |---|---|
  | `gestureRecognizer` | The gesture recognizer which performed the gesture recognition. This is useful to test equality when there are multiple instances of `GestureRecognizer`. |
  | `result` | The `GestureRecognizerResult` object that contains a list of detections, each detection has a bounding box that is expressed in the unrotated input frame of reference coordinates system, i.e. in `[0,image_width) x [0,image_height)`, which are the dimensions of the underlying image data. |
  | `timestampInMilliseconds` | The timestamp (in milliseconds) which indicates when the input image was sent to the gesture recognizer. |
  | `error` | An optional error parameter populated when there is an error in performing gesture recognition on the input live stream image data. |