Camera Selector

Introduction

The Camera Selector module provides a simple interface to switch between available cameras. Two predefined selectors are available:

CamSelector.Back – the device’s default rear camera.

CamSelector.Front – the device’s default front camera.

The selected camera can be managed as a Compose state, allowing seamless integration into composable functions.

Usage Example

The following example demonstrates how to display a camera preview and switch between cameras:

@Composable
fun Camera() {
  var camSelector by remember { mutableStateOf(CamSelector.Back) } // Or CamSelector.Front
  CameraPreview(camSelector = camSelector) {
    Button(onClick = {
      camSelector = camSelector.inverse // Switch Camera
    }) { 
       Text("Switch") 
    }
  }
}

Custom Camera Selector

You can customize the camera selection by using CamSelector. It allows you to specify the camera position and one or more lens types such as Wide, UltraWide, or Telephoto.

These options can be combined to define exactly which cameras are eligible for use.

Usage example

@Composable
fun CameraPreviewScreen() {
  val controller = remember { CameraController() }
  val cameraSession = rememberCameraSession(controller)
  val camSelector = remember {
    CamSelector(
        camPosition = CamPosition.Back,
        camLensTypes = listOf(
          CamLensType.UltraWide,
          CamLensType.Wide,
          CamLensType.Telephoto,
        )
    )
  }

  CameraPreview(
    cameraSession = cameraSession,
    camSelector = camSelector,
  )
}

If the specified camera selector is not supported, the system will fall back to the closest available match.

Note: multi-camera lens support on Android depends on CameraX. Having multiple lenses on a device does not necessarily mean they are supported.

Custom own Camera Selector (Advanced)

For advanced use cases, you can also retrieve the list of available camera devices and explicitly select the desired one.

Usage example

@Composable
fun CameraPreviewScreen() {
  val controller = remember { CameraController() }
  val cameraSession = rememberCameraSession(controller)
  val cameraDevicesState = rememberCameraDeviceState()
  var camSelector by remember { mutableStateOf(CamSelector.Back) }

  LaunchedEffect(cameraDevicesState) {
    if (cameraDevicesState is CameraDeviceState.Devices) {
      val cameraDevices = cameraDevicesState.cameraDevices
      val selectedDevice = cameraDevices.find { /* your logic */ }
      if (selectedDevice != null) {
        camSelector = CamSelector(selectedDevice)
      }
    }
  }

  CameraPreview(
    cameraSession = cameraSession,
    camSelector = camSelector,
  )
}

External Camera (Experimental)

Camposer also supports external cameras, such as Continuity Camera Devices on iOS, UVC cameras (mostly supported on iPad), or cameras supported by CameraX on Android.

Camera Switch Callback (Android only)

To handle events triggered by camera changes, the onPreviewStreamChanged callback is available:

onPreviewStreamChanged: Invoked whenever the camera preview stream changes

onSwitchCameraContent: @Composable (ImageBitmap) -> Unit: Composable invoked whenever the camera preview stream changes, providing the current frame as a Bitmap.

This can be used for tasks such as processing the camera feed or updating UI elements in response to camera switching.