/// <summary>
/// Shut down gaze watcher and stop listening for events.
/// </summary>
private void StopGazeDeviceWatcher()
{
if (gazeDeviceWatcher != null)
{
gazeDeviceWatcher.Stop();
gazeDeviceWatcher.Added -= this.DeviceAdded;
gazeDeviceWatcher.Updated -= this.DeviceUpdated;
gazeDeviceWatcher = null;
}
}
/// <summary>
/// Start gaze watcher and declare watcher event handlers.
/// </summary>
private void StartGazeDeviceWatcher()
{
if (gazeDeviceWatcher == null)
{
gazeDeviceWatcher = GazeInputSourcePreview.CreateWatcher();
gazeDeviceWatcher.Added += this.DeviceAdded;
gazeDeviceWatcher.Updated += this.DeviceUpdated;
gazeDeviceWatcher.Start();
}
}
private void OnDeviceAdded(GazeDeviceWatcherPreview sender, GazeDeviceWatcherAddedPreviewEventArgs args)
{
_devices.Add(args.Device);
if (_devices.Count == 1)
{
IsDeviceAvailableChanged?.Invoke(null, null);
InitializeGazeInputSource();
}
}
/// <summary>
/// Eye-tracking device connected (added, or available when watcher is initialized).
/// </summary>
/// <param name="sender">Source of the device added event</param>
/// <param name="e">Event args for the device added event</param>
private void DeviceAdded(GazeDeviceWatcherPreview source,
GazeDeviceWatcherAddedPreviewEventArgs args)
{
if (IsSupportedDevice(args.Device))
{
deviceCounter++;
TrackerCounter.Text = deviceCounter.ToString();
}
// Set up gaze tracking.
TryEnableGazeTrackingAsync(args.Device);
}
private void StopGazeDeviceWatcher()
{
if (_gazeDeviceWatcher == null)
{
return;
}
_gazeDeviceWatcher.Stop();
_gazeDeviceWatcher.Added -= DeviceAdded;
_gazeDeviceWatcher.Updated -= DeviceUpdated;
_gazeDeviceWatcher.Removed -= DeviceRemoved;
_gazeDeviceWatcher = null;
}
private void OnDeviceAdded(GazeDeviceWatcherPreview sender, GazeDeviceWatcherAddedPreviewEventArgs args)
{
_deviceCount++;
Log($"Device added, count={_deviceCount}", args.Device);
if (!_isSourceHoooked)
{
_source.GazeEntered += OnGazeEntered;
_source.GazeMoved += OnGazeMoved;
_source.GazeExited += OnGazeExited;
_isSourceHoooked = true;
}
}
private void DeviceRemoved(GazeDeviceWatcherPreview source,
GazeDeviceWatcherRemovedPreviewEventArgs args)
{
// Decrement gaze device counter and remove event handlers
if (IsSupportedDevice(args.Device))
{
_deviceCounter--;
if (_deviceCounter == 0)
{
_gazeInputSource.GazeEntered -= GazeEntered;
_gazeInputSource.GazeMoved -= GazeTrackerMoved;
_gazeInputSource.GazeExited -= GazeExited;
}
}
}
/// <summary>
/// Handles disconnection of eye-tracking devices.
/// </summary>
/// <param name="sender">Source of the device removed event</param>
/// <param name="e">Event args for the device removed event</param>
private void DeviceRemoved(GazeDeviceWatcherPreview source,
GazeDeviceWatcherRemovedPreviewEventArgs args)
{
// Decrement gaze device counter and remove event handlers.
if (IsSupportedDevice(args.Device))
{
deviceCounter--;
TrackerCounter.Text = deviceCounter.ToString();
if (deviceCounter == 0)
{
gazeInputSource.GazeEntered -= this.GazeEntered;
gazeInputSource.GazeMoved -= this.GazeMoved;
gazeInputSource.GazeExited -= this.GazeExited;
}
}
}
private void OnDeviceRemoved(GazeDeviceWatcherPreview sender, GazeDeviceWatcherRemovedPreviewEventArgs args)
{
var index = 0;
while (index < _devices.Count && _devices.ElementAt(index).Id != args.Device.Id)
{
index++;
}
if (index < _devices.Count)
{
_devices.RemoveAt(index);
}
else
{
_devices.RemoveAt(0);
}
if (_devices.Count == 0)
{
IsDeviceAvailableChanged?.Invoke(null, null);
}
}
/// <summary>
/// Initial device state might be uncalibrated,
/// but device was subsequently calibrated.
/// </summary>
/// <param name="sender">Source of the device updated event</param>
/// <param name="e">Event args for the device updated event</param>
private void DeviceUpdated(GazeDeviceWatcherPreview source,
GazeDeviceWatcherUpdatedPreviewEventArgs args)
{
// Set up gaze tracking.
TryEnableGazeTrackingAsync(args.Device);
}
private void OnDeviceEnumerationCompleted(GazeDeviceWatcherPreview sender, object args)
{
Log($"Device enumeration complete, count={_deviceCount}");
}
private void OnDeviceUpdated(GazeDeviceWatcherPreview sender, GazeDeviceWatcherUpdatedPreviewEventArgs args)
{
Log("Device updated", args.Device);
}
private void OnDeviceRemoved(GazeDeviceWatcherPreview sender, GazeDeviceWatcherRemovedPreviewEventArgs args)
{
_deviceCount--;
Log($"Device removed, count={_deviceCount}", args.Device);
}
