如何在 Android CameraX 中使用手动对焦？

Question

我正在尝试像在 Camera2 中一样对 CameraX 进行手动对焦 API

在Camera2中API我使用下面的代码

final CaptureRequest.Builder captureBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE); 

captureBuilder.set(CaptureRequest.CONTROL_AF_MODE, CaptureRequest.CONTROL_AF_MODE_OFF); 

captureBuilder.set(CaptureRequest.LENS_FOCUS_DISTANCE, mLensFocusDistance);

可以在 android 相机 X 中进行手动对焦吗？如果是如何

提前致谢

Answer 1

你应该设置 TouchListener 到 textureView 然后设置 focus(Kotlin):

private fun setUpTapToFocus() {
    textureView.setOnTouchListener { _, event ->
        if (event.action != MotionEvent.ACTION_UP) {
            return false
        }

        val cameraControl = CameraX.getCameraControl(CameraX.LensFacing.BACK) // you can set it to front                     
        val factory = TextureViewMeteringPointFactory(textureView)
        val point = factory.createPoint(event.x, event.y)
        val action = FocusMeteringAction.Builder.from(point).build()
        cameraControl.startFocusAndMetering(action)
        return true
    }
}

希望对您有所帮助

Answer 2

有一种方法可以通过使用 Camera2Interop.Extender 访问 low-level camera2 API 在 cameraX 中使用手动对焦。您应该像这样设置两个额外的选项来预览构建器：

void setFocusDistance(ExtendableBuilder<?> builder, float distance) {
    Camera2Interop.Extender extender = new Camera2Interop.Extender(builder);
    extender.setCaptureRequestOption(CaptureRequest.CONTROL_AF_MODE, CameraMetadata.CONTROL_AF_MODE_OFF);
    extender.setCaptureRequestOption(CaptureRequest.LENS_FOCUS_DISTANCE, distance);
}

并在构建您的 cameraX 预览请求时使用它：

float focusDistance = 0F; // example: infinite focus
Preview.Builder previewBuilder = new Preview.Builder();
setFocusDistance(previewBuilder, focusDistance);
preview = previewBuilder.build();
preview.setSurfaceProvider(viewFinder.getSurfaceProvider());

请注意，您也可以通过这种方式设置其他 camera2 CaptureRequest 选项。

以下是如何找到 LENS_INFO_MINIMUM_FOCUS_DISTANCE（通常是 10f 左右的值）：

theCamera = cameraProvider.bindToLifecycle(...
CameraCharacteristics camChars = Camera2CameraInfo
   .extractCameraCharacteristics(theCamera.getCameraInfo());
float discoveredMinFocusDistance = camChars
   .get(CameraCharacteristics.LENS_INFO_MINIMUM_FOCUS_DISTANCE);
Log.i("dev", "found it! " + discoveredMinFocusDistance);

如何在 Android CameraX 中使用手动对焦？

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