使用Camera X库捕获图像后如何自动旋转图像？

如何解决使用Camera X库捕获图像后如何自动旋转图像？

我是使用相机X库的新手。我正在尝试遵循here

中Google的代码实验室

我可以显示预览并捕获图像。但是问题是......

当我以横向捕获图像时，图像结果将仍然为纵向。我想使其自动旋转。如果以风景拍摄图像，则结果应为风景，如果以人像拍摄，则结果应为人像。就像“相机”应用中的相机一样

该怎么做？

我正在使用Redmi Note 7，Android 10。

我使用的gradle：

implementation "androidx.camera:camera-camera2:1.0.0-beta11"
implementation "androidx.camera:camera-lifecycle:1.0.0-beta11"
implementation "androidx.camera:camera-view:1.0.0-alpha18"

这是我的代码，用于显示预览并捕获图像

class CameraFragment : Fragment() {

    private var imageCapture: ImageCapture? = null
    private lateinit var outputDirectory: File
    private lateinit var cameraExecutor: ExecutorService
    private var cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA

    companion object {
        private const val TAG = "CameraFragment"
        private const val FILENAME_FORMAT = "yyyy-MM-dd-HH-mm-ss-SSS"
        private const val CAMERA_REQUEST_CODE_PERMISSIONS = 10
    }

    lateinit var mContext : Context
    lateinit var mActivity : FragmentActivity

   

    override fun onAttach(context: Context) {
        super.onAttach(context)

        mContext = context
        activity?.let { mActivity = it }

    }


    private fun getOutputDirectory(): File {
        val mediaDir = mActivity.externalMediaDirs.firstOrNull()?.let {
            File(it,resources.getString(R.string.app_name)).apply { mkdirs() }
        }
        return if (mediaDir != null && mediaDir.exists())
            mediaDir else mActivity.filesDir
    }


    private fun startCamera() {
        val cameraProviderFuture = ProcessCameraProvider.getInstance(mContext)

        cameraProviderFuture.addListener(Runnable {
            // Used to bind the lifecycle of cameras to the lifecycle owner
            val cameraProvider: ProcessCameraProvider = cameraProviderFuture.get()

            // Preview
            val preview = Preview.Builder()
                    .build()
                    .also {
                        it.setSurfaceProvider(previewView.surfaceProvider)
                    }


            imageCapture = ImageCapture.Builder().build()


            try {
                // Unbind use cases before rebinding
                cameraProvider.unbindAll()

                // Bind use cases to camera
                cameraProvider.bindToLifecycle(
                        this,cameraSelector,preview,imageCapture)

            } catch (exc: Exception) {
                Log.e(TAG,"Use case binding failed",exc)
            }

        },ContextCompat.getMainExecutor(mContext))
    }


    private fun takePhoto() {

        // Get a stable reference of the modifiable image capture use case
        val imageCapture = imageCapture ?: return


        // Create time-stamped output file to hold the image
        val photoFile = File(
                outputDirectory,SimpleDateFormat(FILENAME_FORMAT,Locale.US
                ).format(System.currentTimeMillis()) + ".jpg")

        // Create output options object which contains file + metadata
        val outputOptions = ImageCapture.OutputFileOptions.Builder(photoFile).build()


        // Set up image capture listener,which is triggered after photo has
        // been taken
        imageCapture.takePicture(outputOptions,ContextCompat.getMainExecutor(mContext),object : ImageCapture.OnImageSavedCallback {

            override fun onError(exc: ImageCaptureException) {
                Log.d("agungxxx","2: ${exc.localizedMessage}")
                Log.e(TAG,"Photo capture failed: ${exc.message}",exc)
            }

            override fun onImageSaved(output: ImageCapture.OutputFileResults) {
                cameraSharedViewModel.sendImageUriPathToPreviousDestination(photoFile)
                findNavController().navigateUp()
            }
        })

    }

}

解决方法

捕获的图像的旋转取决于ImageCapture用例中的the target rotation。默认情况下，当应用程序未设置时，它等于Display.getRotation()，其中Display是创建ImageCapture用例时的默认显示。

这意味着您需要在每次显示器方向改变时（例如，每次更改ImageCapture）更改目标val orientationEventListener = object : OrientationEventListener(this) { override fun onOrientationChanged(orientation: Int) { if (orientation == OrientationEventListener.UNKNOWN_ORIENTATION) { return } val rotation = when (orientation) { in 45 until 135 -> Surface.ROTATION_270 in 135 until 225 -> Surface.ROTATION_180 in 225 until 315 -> Surface.ROTATION_90 else -> Surface.ROTATION_0 } imageCapture.targetRotation = rotation } } 的旋转角度。当设备从纵向旋转到横向旋转时。

我假设您的活动方向已锁定（？）。在这种情况下，您可以使用OrientationEventListener来连续获取设备旋转的更新，然后相应地更新用例的目标旋转。

orientationEventListener

您应该在活动的生命周期启动/停止时启动/停止{{1}}，这也与相机的启动/停止时相匹配。您可以看到此here的示例。

您还可以进一步了解CameraX的用例和轮换方式in the official documentation。