如何在使用 Camera X 库捕获图像后自动旋转图像？

Question

我是使用相机 X 库的新手。我正在尝试关注 here

中 Google 的代码实验室

我可以显示预览并捕获图像。但问题是......

当我拍摄横向图像时，图像结果仍为纵向。我想让它自动旋转。如果我拍摄横向图像，那么结果应该是横向的，如果我拍摄纵向图像，那么结果应该是纵向的。就像 'Camera' 应用程序

中的相机

怎么做？

我用的是红米Note 7，Android10.

我用的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"

这是我用来显示预览和捕获图像的代码

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()
            }
        })

    }

}

Answer 1

捕获图像的旋转取决于 ImageCapture 用例的 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方向发生变化时更新 ImageCapture 的目标旋转，例如当设备从纵向旋转到横向时。

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

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
    }
}

当 Activity 的生命周期为 started/stopped 时，您应该 start/stop orientationEventListener，这也与相机的 started/stopped 相匹配。你可以看到这个 here.

的例子

您还可以了解有关 CameraX 的用例和旋转的更多信息in the official documentation。

如何在使用 Camera X 库捕获图像后自动旋转图像？

how to automatically rotate the image after capturing image using Camera X library?

android

android-jetpack

android-camerax