/// <summary>
/// Cleans up the camera resources (after stopping any video recording and/or preview if necessary) and unregisters from MediaCapture events
/// </summary>
/// <returns></returns>
private async Task CleanupCameraAsync()
{
Debug.WriteLine("CleanupCameraAsync");
if (_isInitialized)
{
// If a recording is in progress during cleanup, stop it to save the recording
if (_isPreviewing)
{
// The call to stop the preview is included here for completeness, but can be
// safely removed if a call to MediaCapture.Dispose() is being made later,
// as the preview will be automatically stopped at that point
await StopPreviewAsync();
}
_isInitialized = false;
}
if (_mediaCapture != null)
{
_mediaCapture.Failed -= MediaCapture_Failed;
_mediaCapture.Dispose();
_mediaCapture = null;
}
if (_rotationHelper != null)
{
_rotationHelper.OrientationChanged -= RotationHelper_OrientationChanged;
_rotationHelper = null;
}
}
/// <summary>
/// Uses the current device orientation in space and page orientation on the screen to calculate the rotation
/// transformation to apply to the controls
/// </summary>
private void UpdateButtonOrientation()
{
// Rotate the buttons in the UI to match the rotation of the device
var angle = CameraRotationHelper.ConvertSimpleOrientationToClockwiseDegrees(_rotationHelper.GetUIOrientation());
var transform = new RotateTransform {
Angle = angle
};
// The RenderTransform is safe to use (i.e. it won't cause layout issues) in this case, because these buttons have a 1:1 aspect ratio
PhotoButton.RenderTransform = transform;
}
/// <summary>
/// Gets the current orientation of the UI in relation to the device (when AutoRotationPreferences cannot be honored) and applies a corrective rotation to the preview
/// </summary>
private async Task SetPreviewRotationAsync()
{
// Only need to update the orientation if the camera is mounted on the device
if (_externalCamera)
{
return;
}
// Add rotation metadata to the preview stream to make sure the aspect ratio / dimensions match when rendering and getting preview frames
var rotation = _rotationHelper.GetCameraPreviewOrientation();
var props = _mediaCapture.VideoDeviceController.GetMediaStreamProperties(MediaStreamType.VideoPreview);
props.Properties.Add(RotationKey, CameraRotationHelper.ConvertSimpleOrientationToClockwiseDegrees(rotation));
await _mediaCapture.SetEncodingPropertiesAsync(MediaStreamType.VideoPreview, props, null);
}
/// <summary>
/// Initializes the MediaCapture, registers events, gets camera device information for mirroring and rotating, starts preview and unlocks the UI
/// </summary>
/// <returns></returns>
private async Task InitializeCameraAsync()
{
Debug.WriteLine("InitializeCameraAsync");
if (_mediaCapture == null)
{
// Attempt to get the back camera if one is available, but use any camera device if not
var cameraDevice = await FindCameraDeviceByPanelAsync(Windows.Devices.Enumeration.Panel.Back);
if (cameraDevice == null)
{
Debug.WriteLine("No camera device found!");
return;
}
// Create MediaCapture and its settings
_mediaCapture = new MediaCapture();
// Register for a notification when video recording has reached the maximum time and when something goes wrong
_mediaCapture.Failed += MediaCapture_Failed;
var settings = new MediaCaptureInitializationSettings {
VideoDeviceId = cameraDevice.Id
};
// Initialize MediaCapture
try
{
await _mediaCapture.InitializeAsync(settings);
_isInitialized = true;
}
catch (UnauthorizedAccessException)
{
Debug.WriteLine("The app was denied access to the camera");
}
// If initialization succeeded, start the preview
if (_isInitialized)
{
// Figure out where the camera is located
if (cameraDevice.EnclosureLocation == null || cameraDevice.EnclosureLocation.Panel == Windows.Devices.Enumeration.Panel.Unknown)
{
// No information on the location of the camera, assume it's an external camera, not integrated on the device
_externalCamera = true;
}
else
{
// Camera is fixed on the device
_externalCamera = false;
// Only mirror the preview if the camera is on the front panel
_mirroringPreview = (cameraDevice.EnclosureLocation.Panel == Windows.Devices.Enumeration.Panel.Front);
}
// Initialize rotationHelper
_rotationHelper = new CameraRotationHelper(cameraDevice.EnclosureLocation);
_rotationHelper.OrientationChanged += RotationHelper_OrientationChanged;
await StartPreviewAsync();
UpdateCaptureControls();
}
}
}
