DisplayOrientedMeteringPointFactory

Kotlin |Java

class DisplayOrientedMeteringPointFactory : MeteringPointFactory

kotlin.Any
↳	androidx.camera.core.MeteringPointFactory
	↳	androidx.camera.core.DisplayOrientedMeteringPointFactory

A MeteringPointFactory that can convert a View (x, y) into a MeteringPoint which can then be used to construct a FocusMeteringAction to start a focus and metering action.

For apps showing full camera preview in a View without any scaling, cropping or rotating applied, they can simply use view width and height to create the DisplayOrientedMeteringPointFactory and then pass View (x, y) to create a MeteringPoint. This factory will convert the (x, y) into the sensor (x, y) based on display rotation and lensFacing.

If camera preview is scaled, cropped or rotated in the View, it is applications' duty to transform the coordinates properly so that the width and height of this factory represents the full Preview FOV and also the (x,y) passed to create MeteringPoint needs to be adjusted by apps to the coordinates left-top (0,0) - right-bottom (width, height). For example, if the preview is scaled to 2X from the center and is cropped in a View. Assuming that the dimension of View is (240, 320), then the width/height of this DisplayOrientedMeteringPointFactory should be (480, 640). And the (x, y) from the View should be converted to (x + (480-240)/2, y + (640 - 320)/2) first.

Summary

Public constructors
`<init>(@NonNull display: Display, @NonNull cameraInfo: CameraInfo, width: Float, height: Float)` Creates a `DisplayOrientedMeteringPointFactory` for converting View (x, y) into a `MeteringPoint` based on the current display's rotation and `CameraInfo`.

Inherited functions

From class MeteringPointFactory

MeteringPoint

createPoint(x: Float, y: Float)

Creates a MeteringPoint by x, y.

The (x, y) is a position from the area defined by the specific MeteringPointFactory implementation, such as DisplayOrientedMeteringPointFactory or SurfaceOrientedMeteringPointFactory.

MeteringPoint

createPoint(x: Float, y: Float, size: Float)

Creates a MeteringPoint by x, y, size.

The (x, y) is a position from the area defined by the specific MeteringPointFactory implementation, such as DisplayOrientedMeteringPointFactory or SurfaceOrientedMeteringPointFactory.

Float

getDefaultPointSize()

Returns default point size. It is the default size of the MeteringPoint width and height (ranging from 0 to 1) which is a (normalized) percentage of the sensor width/height (or crop region width/height if crop region is set).

Public constructors

<init>

DisplayOrientedMeteringPointFactory(
    @NonNull display: Display, 
    @NonNull cameraInfo: CameraInfo, 
    width: Float, 
    height: Float)

Creates a DisplayOrientedMeteringPointFactory for converting View (x, y) into a MeteringPoint based on the current display's rotation and CameraInfo.

The width/height of this factory forms a coordinate left-top (0, 0) - right-bottom (width, height) which represents the full camera preview FOV in the display's orientation. For apps showing full camera preview in a View, it is as simple as passing View's width/height and passing View (x, y) directly to create a MeteringPoint. Otherwise the (x, y) passed to MeteringPointFactory#createPoint(float, float) should be adjusted to this coordinate system first.

Parameters
`display`	Display: `Display` to get the orientation from. This should be the current display where camera preview is showing.
`cameraInfo`	CameraInfo: the information for the `Camera` to generate the metering point for
`width`	Float: the width of the coordinate which are mapped to the full camera preview FOV in given display's orientation.
`height`	Float: the height of the coordinate which are mapped to the full camera preview FOV in given display's orientation.