ImageCapture

open class ImageCapture : UseCase
kotlin.Any
   ↳ androidx.camera.core.UseCase
   ↳ androidx.camera.core.ImageCapture

A use case for taking a picture.

This class is designed for basic picture taking. It provides takePicture() functions to take a picture to memory or save to a file, and provides image metadata. Pictures are taken in automatic mode after focus has converged. The flash mode can additionally be set by the application.

TakePicture returns immediately and a listener is called to provide the results after the capture completes. Multiple calls to takePicture will take pictures sequentially starting after the previous picture is captured.

Note that focus and exposure metering regions can be controlled via Preview.

When capturing to memory, the captured image is made available through an ImageProxy via an ImageCapture.OnImageCapturedCallback.

Summary

Nested classes

Builder for an ImageCapture.

Capture mode options for ImageCapture.

Describes the error that occurred during an image capture operation (such as ).

Holder class for metadata that will be saved with captured images.
abstract

Callback for when an image capture has completed.
abstract

Listener containing callbacks for image file I/O events.

Public methods
open Int

Get the flash mode.
open Unit
setFlashMode(flashMode: Int)

Set the flash mode.
open Unit
setTargetAspectRatioCustom(@NonNull aspectRatio: Rational)

Sets target aspect ratio.
open Unit

Sets the desired rotation of the output image.
open Unit
takePicture(@NonNull executor: Executor, @NonNull callback: ImageCapture.OnImageCapturedCallback)

Captures a new still image for in memory access.
open Unit
takePicture(@NonNull saveLocation: File, @NonNull executor: Executor, @NonNull imageSavedCallback: ImageCapture.OnImageSavedCallback)

Captures a new still image and saves to a file.
open Unit
takePicture(@NonNull saveLocation: File, @NonNull metadata: ImageCapture.Metadata, @NonNull executor: Executor, @NonNull imageSavedCallback: ImageCapture.OnImageSavedCallback)

Captures a new still image and saves to a file along with application specified metadata.
open String

Public methods

getFlashMode

open fun getFlashMode(): Int

Get the flash mode.

Return
Int: the FlashMode.

setFlashMode

open fun setFlashMode(flashMode: Int): Unit

Set the flash mode.

The flash control for the subsequent photo capture requests. See FlashMode for the optional settings. Applications can check if there is a flash unit via CameraInfo#hasFlashUnit() and update UI component if necessary. If there is no flash unit, then calling this API will take no effect for the subsequent photo capture requests and they will act like FlashMode#OFF.

When the torch is enabled via CameraControl#enableTorch(boolean), the torch will remain enabled during photo capture regardless of FlashMode setting. When the torch is disabled, flash will function as specified by setFlashMode(int).

Parameters
flashMode Int: the FlashMode.

setTargetAspectRatioCustom

open fun setTargetAspectRatioCustom(@NonNull aspectRatio: Rational): Unit

Sets target aspect ratio.

This sets the cropping rectangle returned by ImageProxy#getCropRect() returned from ImageCapture#takePicture(Executor, OnImageCapturedCallback).

This crops the saved image when calling ImageCapture#takePicture(File, Executor, OnImageSavedCallback) or ImageCapture#takePicture(File, Metadata, Executor, OnImageSavedCallback).

Cropping occurs around the center of the image and as though it were in the target rotation.

Parameters
aspectRatio Rational: New target aspect ratio.

setTargetRotation

open fun setTargetRotation(rotation: Int): Unit

Sets the desired rotation of the output image.

This will affect the EXIF rotation metadata in images saved by takePicture calls and the rotation value returned by OnImageCapturedCallback. These will be set to be the rotation, which if applied to the output image data, will make the image match target rotation specified here.

While rotation can also be set via Builder#setTargetRotation(int), using ImageCapture#setTargetRotation(int) allows the target rotation to be set dynamically.

In general, it is best to use an android.view.OrientationEventListener to set the target rotation. This way, the rotation output will indicate which way is down for a given image. This is important since display orientation may be locked by device default, user setting, or app configuration, and some devices may not transition to a reverse-portrait display orientation. In these cases, use ImageCapture#setTargetRotation to set target rotation dynamically according to the android.view.OrientationEventListener, without re-creating the use case. Note the OrientationEventListener output of degrees in the range [0..359] should be converted to a surface rotation, i.e. one of Surface#ROTATION_0, Surface#ROTATION_90, Surface#ROTATION_180, or Surface#ROTATION_270.

If no target rotation is set by the application, it is set to the value of Display#getRotation() of the default display at the time the use case is created.

takePicture uses the target rotation at the time it begins executing (which may be delayed waiting on a previous takePicture call to complete).

Parameters
rotation Int: Target rotation of the output image, expressed as one of Surface#ROTATION_0, Surface#ROTATION_90, Surface#ROTATION_180, or Surface#ROTATION_270.

takePicture

open fun takePicture(@NonNull executor: Executor, @NonNull callback: ImageCapture.OnImageCapturedCallback): Unit

Captures a new still image for in memory access.

The callback will be called only once for every invocation of this method. The listener is responsible for calling Image#close() on the returned image.

Parameters
executor Executor: The executor in which the callback methods will be run.
callback Executor: Callback to be invoked for the newly captured image

takePicture

open fun takePicture(@NonNull saveLocation: File, @NonNull executor: Executor, @NonNull imageSavedCallback: ImageCapture.OnImageSavedCallback): Unit

Captures a new still image and saves to a file.

The listener's callback will be called only once for every invocation of this method.

Parameters
saveLocation File: Location to store the newly captured image.
executor File: The executor in which the listener callback methods will be run.
imageSavedCallback File: Callback to be called for the newly captured image.

takePicture

open fun takePicture(@NonNull saveLocation: File, @NonNull metadata: ImageCapture.Metadata, @NonNull executor: Executor, @NonNull imageSavedCallback: ImageCapture.OnImageSavedCallback): Unit

Captures a new still image and saves to a file along with application specified metadata.

The callback will be called only once for every invocation of this method.

This function accepts metadata as a parameter from application code. For JPEGs, this metadata will be included in the EXIF.

Parameters
saveLocation File: Location to store the newly captured image.
metadata File: Metadata to be stored with the saved image. For JPEG this will be included in the EXIF.
executor File: The executor in which the callback methods will be run.
imageSavedCallback File: Callback to be called for the newly captured image.

toString

@NonNull open fun toString(): String