我的用例是一次拍摄两张图像。第一个为2倍变焦,第二个为1倍变焦。另外,我想将图像保存到文件。
我的想法是以2倍变焦拍摄第一张图像,保存图像时将变焦等级设置为1倍,当镜头变焦至1倍变焦等级时拍摄第二张图像。
但是,当我拍摄第一张图像时,预览卡在第一张图像上,并且从设置1倍变焦进行回调从未发生。
这就是我创建捕获用例的方式。
private void createImageCaptureUseCases() {
ImageCapture imageCapture1 = new ImageCapture.Builder()
.setCaptureMode(ImageCapture.CAPTURE_MODE_MINIMIZE_LATENCY)
.build();
ImageCapture imageCapture2 = new ImageCapture.Builder()
.setCaptureMode(ImageCapture.CAPTURE_MODE_MINIMIZE_LATENCY)
.build();
imageCaptureUseCases.clear();
imageCaptureUseCases.add(imageCapture1);
imageCaptureUseCases.add(imageCapture2);
这是我第一次开始相机会话的方式。
ListenableFuture<ProcessCameraProvider> cameraProviderFuture = ProcessCameraProvider.getInstance(getContext());
cameraProviderFuture.addListener(() -> {
try {
cameraProvider = cameraProviderFuture.get();
preview = new Preview.Builder().build();
cameraSelector = new CameraSelector.Builder()
.requireLensFacing(CameraSelector.LENS_FACING_BACK)
.build();
Camera camera = cameraProvider.bindToLifecycle(
((LifecycleOwner) this),
cameraSelector,
preview,
imageCapture);
camera.getCameraControl().setZoomRatio(2f);
preview.setSurfaceProvider(previewView.createSurfaceProvider(camera.getCameraInfo()));
} catch (InterruptedException | ExecutionException e) {}
}, ContextCompat.getMainExecutor(getContext()));
这就是捕获图像的调用方式。
private void captureImage(ImageCapture imageCapture) {
File pictureFile = ImageUtils.createImageFile(getActivity());
ImageCapture.OutputFileOptions options = new
ImageCapture.OutputFileOptions.Builder(pictureFile).build();
final Activity activity = getActivity();
imageCapture.takePicture(options, ContextCompat.getMainExecutor(activity),
new ImageCapture.OnImageSavedCallback() {
@Override
public void onImageSaved(@NonNull ImageCapture.OutputFileResults outputFileResults){
Log.i("my tag", "image Saved: " + pictureFile.getAbsolutePath());
int index = imageCaptureUseCases.indexOf(imageCapture);
cameraProvider.unbind(imageCapture);
if (index < imageCaptureUseCases.size() - 1) {
Camera camera = cameraProvider.bindToLifecycle(
(LifecycleOwner) activity,
cameraSelector,
imageCaptureUseCases.get(index + 1));
ListenableFuture future = camera.getCameraControl().setZoomRatio(1f);
future.addListener(() -> captureImage(imageCaptureUseCases.get(index + 1)),
ContextCompat.getMainExecutor(activity));
} else {
createImageCaptureUseCases();
cameraProvider.unbindAll();
Camera camera = cameraProvider.bindToLifecycle(
(LifecycleOwner) activity,
cameraSelector,
preview,
imageCaptureUseCases.get(0));
camera.getCameraControl().setZoomRatio(2f);
}
}
@Override
public void onError(@NonNull ImageCaptureException exception) {
Log.i("my tag", "image save error: " + pictureFile.getAbsolutePath());
}
});
}
您不需要多个ImageCapture
实例来以2的缩放比例捕获图像,您可以使用相同的实例,ImageCapture
可以拍摄并保存/提供照片,而与诸如缩放比例。
查看您的代码示例,似乎您第二次尝试捕获图像(具有不同的缩放比例)时可能没有绑定Preview
用例,但是我可能会弄错。请记住,ImageCapture
用例不能单独绑定,它必须与至少1个Preview
或ImageAnalysis
用例绑定。
以下是捕获2张图像的示例,每个图像具有不同的缩放比例。该代码包含一些重复,并且全部在1个块中,因此可以肯定地对其进行改进。
private fun setUpCamera() {
val mainExecutor = ContextCompat.getMainExecutor(this)
val cameraProviderFuture = ProcessCameraProvider.getInstance(this)
cameraProviderFuture.addListener(Runnable {
// Wait for the camera provider to be retrieved
val cameraProvider = cameraProviderFuture.get()
// Build your use cases
val preview = Preview.Builder().build()
val imageCapture = ImageCapture.Builder().build()
// Get a camera selector to use
val cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA
// Bind the use cases to a lifecycle
val camera = cameraProvider.bindToLifecycle(this, cameraSelector, preview, imageCapture)
// Set the preview surface provider
preview.setSurfaceProvider(previewView.createSurfaceProvider(camera.cameraInfo))
// Set the zoom ratio for the first photo
val cameraControl = camera.cameraControl
cameraControl.setZoomRatio(1F)
// When the previewView is clicked, take the photos
previewView.setOnClickListener {
imageCapture.takePicture(createOutputFilesOptions(), mainExecutor, object : ImageCapture.OnImageSavedCallback {
override fun onImageSaved(outputFileResults: ImageCapture.OutputFileResults) {
// First image captured and saved successfully
Log.d(TAG, "OnImageSavedCallback.onImageSaved: Image saved with zoom ratio 1F")
// Set a new zoom ratio for the second image capture
cameraControl.setZoomRatio(2F)
// Capture the second picture with a different zoom ratio
imageCapture.takePicture(createOutputFilesOptions(), mainExecutor, object : ImageCapture.OnImageSavedCallback {
override fun onImageSaved(outputFileResults: ImageCapture.OutputFileResults) {
// Second image captured and saved successfully
Log.d(TAG, "OnImageSavedCallback.onImageSaved: Image saved with zoom ratio 2F")
}
override fun onError(exception: ImageCaptureException) {
Log.e(TAG, "OnImageSavedCallback.onError", exception)
}
})
}
override fun onError(exception: ImageCaptureException) {
Log.e(TAG, "OnImageSavedCallback.onError", exception)
}
})
}
}, mainExecutor)
}
}