androidx.camera.viewfinder.compose

Standalone Composable Viewfinder for Camera

Interfaces

`CoordinateTransformer`	Coordinate transformer that's used to convert coordinates from one space to another.
`MutableCoordinateTransformer`	CoordinateTransformer where the transformMatrix is mutable.
`ViewfinderInitScope`	A scoped environment provided when a `Viewfinder` is first initialized.

Objects

IdentityCoordinateTransformer

CoordinateTransformer where the transformMatrix is the identity matrix.

Top-level functions summary

`MutableCoordinateTransformer`	`MutableCoordinateTransformer(matrix: Matrix)` Creates a `MutableCoordinateTransformer` with the given matrix as the transformMatrix.
`Unit`	`@Composable Viewfinder( surfaceRequest: ViewfinderSurfaceRequest, modifier: Modifier, transformationInfo: TransformationInfo, coordinateTransformer: MutableCoordinateTransformer?, alignment: Alignment, contentScale: ContentScale, onInit: ViewfinderInitScope.() -> Unit )` Displays a media stream with the given transformations for crop and rotation while maintaining proper scaling.

Top-level functions

MutableCoordinateTransformer

Artifact: androidx.camera.viewfinder:viewfinder-compose

View Source

Added in 1.6.0-alpha01

fun MutableCoordinateTransformer(matrix: Matrix = Matrix()): MutableCoordinateTransformer

Creates a MutableCoordinateTransformer with the given matrix as the transformMatrix.

Viewfinder

Artifact: androidx.camera.viewfinder:viewfinder-compose

View Source

Added in 1.5.0

@Composable
fun Viewfinder(
    surfaceRequest: ViewfinderSurfaceRequest,
    modifier: Modifier = Modifier,
    transformationInfo: TransformationInfo = DEFAULT,
    coordinateTransformer: MutableCoordinateTransformer? = null,
    alignment: Alignment = Alignment.Center,
    contentScale: ContentScale = ContentScale.Crop,
    onInit: ViewfinderInitScope.() -> Unit
): Unit

Displays a media stream with the given transformations for crop and rotation while maintaining proper scaling.

A Surface for the given ViewfinderSurfaceRequest can be retrieved from the ViewfinderSurfaceSessionScope of the callback registered via ViewfinderInitScope.onSurfaceSession in onInit.

This has two underlying implementations based on androidx.compose.foundation.AndroidEmbeddedExternalSurface for ImplementationMode.EMBEDDED or on androidx.compose.foundation.AndroidExternalSurface for ImplementationMode.EXTERNAL. These can be set by the ImplementationMode argument in the surfaceRequest constructor. If implementationMode is null, a default is chosen based on device compatibility. This default value, which can be retrieved from ViewfinderDefaults.implementationMode, will be ImplementationMode.EXTERNAL by default, switching to ImplementationMode.EMBEDDED on API levels 24 and below, or on devices with known compatibility issues with the EXTERNAL mode.

The onInit lambda, and the callback registered with ViewfinderInitScope.onSurfaceSession, are always called from the main thread. onInit will be called every time a new surfaceRequest is provided, or if the ImplementationMode changes.

Parameters
`surfaceRequest: ViewfinderSurfaceRequest`	Details about the surface being requested
`modifier: Modifier = Modifier`	Modifier to be applied to the `Viewfinder`
`transformationInfo: TransformationInfo = DEFAULT`	Specifies the required transformations for the media being displayed.
`coordinateTransformer: MutableCoordinateTransformer? = null`	Coordinate transformer that can be used to convert Compose space coordinates such as touch coordinates to surface space coordinates. When the Viewfinder is displaying content from the camera, this transformer can be used to translate touch events into camera sensor coordinates for focus and metering actions.
`alignment: Alignment = Alignment.Center`	Optional alignment parameter used to place the `Surface` in the given bounds of the `Viewfinder`. Defaults to `Alignment.Center`.
`contentScale: ContentScale = ContentScale.Crop`	Optional scale parameter used to determine the aspect ratio scaling to be used to fit the `Surface` in the bounds of the `Viewfinder`. Defaults to `ContentScale.Crop`.
`onInit: ViewfinderInitScope.() -> Unit`	Lambda invoked on first composition and any time a new `surfaceRequest` is provided. This lambda can be used to declare a `ViewfinderInitScope.onSurfaceSession` callback that will be called each time a new `Surface` is provided by the viewfinder. TODO(b/322420487): Add a sample with `@sample`