FaceDetectionController class

Controller that manages camera initialization, face detection, and optional face verification.

// Basic usage — any face unlocks
final controller = FaceDetectionController()..initializeCamera();

// With verification — only enrolled faces unlock
final controller = FaceDetectionController(
  verificationProvider: LocalFaceVerificationProvider(),
)..initializeCamera();
Inheritance

Constructors

FaceDetectionController({void onFaceSnapshot(List<Face>)?, CameraController? cameraController, CameraLensDirection camDirection = CameraLensDirection.front, ResolutionPreset resolution = ResolutionPreset.low, Duration initTimeout = const Duration(seconds: 10), Duration detectionInterval = const Duration(milliseconds: 300), Duration lockDelay = const Duration(milliseconds: 500), Duration unlockDelay = Duration.zero, double minFaceSize = 0.15, FaceVerificationProvider? verificationProvider, bool enableLiveness = true, int? maxFaces, MultiFacePolicy multiFacePolicy = MultiFacePolicy.lockIfMultiple, bool batteryAwareMode = false, int batteryThreshold = 20, Duration lowBatteryDetectionInterval = const Duration(milliseconds: 1000), Battery? battery})

Properties

batteryAwareMode → bool
Whether to reduce detection frequency when battery is low. Defaults to false (opt-in).
final
batteryThreshold → int
Battery level (0–100) below which low-battery detection interval applies. Only used when batteryAwareMode is true. Defaults to 20.
final
camDirection → CameraLensDirection
Camera lens direction. Defaults to front camera.
final
cameraController → CameraController?
Use an existing camera controller for fine-grained camera control.
final
detectionInterval → Duration
Minimum interval between detection runs. Frames arriving faster than this are skipped. Defaults to 300ms (~3 detections/sec).
final
enableLiveness → bool
Whether to run liveness checks during verification. Only used when verificationProvider is set. Defaults to true.
final
hashCode → int
The hash code for this object.
no setterinherited
hasListeners → bool
Whether any listeners are currently registered.
no setterinherited
initTimeout → Duration
Timeout for camera initialization. Defaults to 10 seconds.
final
lockDelay → Duration
Delay before locking after the last face disappears. Prevents flicker when a face is momentarily lost. Defaults to 500ms.
final
lowBatteryDetectionInterval → Duration
Detection interval used when battery is below batteryThreshold. Only used when batteryAwareMode is true. Defaults to 1000ms.
final
maxFaces → int?
Maximum number of faces allowed before locking. When null (default), any number of faces is accepted.
final
minFaceSize → double
Minimum face size relative to the image (0.0–1.0). Smaller values detect faces further away. Defaults to 0.15.
final
multiFacePolicy → MultiFacePolicy
Policy for handling multiple detected faces. Only applies when maxFaces is set. Defaults to MultiFacePolicy.lockIfMultiple.
final
onFaceSnapshot → void Function(List<Face>)?
Callback invoked with the list of detected faces each time a face is found.
final
resolution → ResolutionPreset
Camera resolution preset. Defaults to ResolutionPreset.low for optimal detection performance and battery usage.
final
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
state → FaceDetectionState
The current state of face detection.
no setter
stream → Stream<FaceDetectionState>
A broadcast stream of state changes.
no setter
unlockDelay → Duration
Delay before unlocking after a face first appears. Prevents flicker from brief false positives. Defaults to 0ms (instant).
final
verificationProvider → FaceVerificationProvider?
Optional face verification provider. When set, detected faces are verified against enrolled templates before unlocking.
final

Methods

addListener(VoidCallback listener) → void
Register a closure to be called when the object changes.
inherited
close() → Future<void>
Release all resources — camera, detector, stream, listeners.
dispose() → void
Discards any resources used by the object. After this is called, the object is not in a usable state and should be discarded (calls to addListener will throw after the object is disposed).
inherited
initializeCamera() → void
Initialize the camera and start the face detection image stream.
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
notifyListeners() → void
Call all the registered listeners.
inherited
pause() → void
Pause face detection (e.g. when the app is backgrounded).
removeListener(VoidCallback listener) → void
Remove a previously registered closure from the list of closures that are notified when the object changes.
inherited
resume() → void
Resume face detection after a pause.
simulateFaceDetected() → void
Simulate a face being detected. Only for use in tests.
simulateNoFace() → void
Simulate no face being detected. Only for use in tests.
toString() → String
A string representation of this object.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited