FocusMeteringAction

class FocusMeteringAction

A configuration used to trigger a focus and/or metering action.

A FocusMeteringAction must be created by the Builder. To construct a Builder, a MeteringPoint is required to specify the focus/metering area. Apps can use various MeteringPointFactory to create the points. After the FocusMeteringAction is built, apps can pass it to startFocusAndMetering to initiate the focus and metering action.

When specifying a MeteringPoint, a metering mode can also be specified. Metering mode is a combination of flags consisting of FLAG_AF, FLAG_AE, and FLAG_AWB. This combination indicates whether the MeteringPoint is used to set an AF(Auto Focus) region, AE(Auto Exposure) region or AWB(Auto White Balance) region. The default meteringMode is FLAG_AF | FLAG_AE | FLAG_AWB which means the point is used for all AF/AE/AWB regions. Apps can set the proper metering mode to optionally exclude some 3A regions. Multiple regions for specific 3A types are also supported via addPoint or addPoint. An app can also use this API to enable different regions for AF and AE respectively.

If any AF points are specified, it will trigger autofocus to start a manual scan. When focus is locked and the specified AF/AE/AWB regions are updated in capture result, the returned ListenableFuture in startFocusAndMetering will complete with isFocusSuccessful set to indicate if focus is done successfully or not. If an AF point is not specified, it will not trigger autofocus and simply wait for specified AE/AWB regions being updated to complete the returned ListenableFuture. In the case of AF points not specified, isFocusSuccessful will be set to false. If Af points are specified but current camera does not support auto focus, isFocusSuccessful will be set to true .

App can set a auto-cancel duration to let CameraX call cancelFocusAndMetering automatically in the specified duration. By default the auto-cancel duration is 5 seconds. Apps can call disableAutoCancel to disable auto-cancel.

Summary

const val FLAG_AE = 2: Int

const val FLAG_AF = 1: Int

const val FLAG_AWB = 4: Int

fun getAutoCancelDurationInMillis(): Long

fun getMeteringPointsAe(): (Mutable)List<MeteringPoint!>

fun getMeteringPointsAf(): (Mutable)List<MeteringPoint!>

fun getMeteringPointsAwb(): (Mutable)List<MeteringPoint!>

fun isAutoCancelEnabled(): Boolean