如何使用Android CameraX API缩放相机？

Question

我试着用下面的代码放大相机，使用CameraX。

首先，我从Preview获得了一个CameraX，并尝试使用Preview进行缩放，如下所示。

var config = CameraX.getDefaultUseCaseConfig(PreviewConfig::class.java, lensFacing)
var preview = Preview(config)
preview.zoom(zoom)

在preview.zoom()之后，我只需要再次绑定CameraX，得到一些错误，它就不能工作了。

CameraX.bindToLifecycle(this, preview, imageCapture, videoCapture)

当上面的代码不起作用时，我先尝试使用CameraX.unbindAll()，然后调用CameraX.bindToLifecycle()。但再次面对一些错误，无法在变焦方面取得成功。

CameraX 让我知道如何使用 API.放大摄像机。

更新错误日志如下：

仅使用CameraX.bindToLifecycle()**:** 错误日志

java.lang.IllegalArgumentException: Exceeded max simultaneously bound image capture use cases.
   at androidx.camera.camera2.impl.UseCaseSurfaceOccupancyManager.checkUseCaseLimitNotExceeded(UseCaseSurfaceOccupancyManager.java:61)
   at androidx.camera.camera2.impl.Camera2DeviceSurfaceManager.getSuggestedResolutions(Camera2DeviceSurfaceManager.java:146)
   at androidx.camera.core.CameraX.calculateSuggestedResolutions(CameraX.java:449)
   at androidx.camera.core.CameraX.bindToLifecycle(CameraX.java:144)
   at com.android.example.cameraxbasic.fragments.CameraFragment$updateCameraUi$2.onTouch(CameraFragment.kt:408)
   at android.view.View.dispatchTouchEvent(View.java:12512)
   at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3032)
   at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2719)
   at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3032)
   at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2719)
   at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3032)
   at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2719)
   at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3032)
   at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2719)
   at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3032)
   at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2719)
   at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3032)
   at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2719)
   at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3032)
   at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2719)
   at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:3032)
   at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2719)
   at com.android.internal.policy.DecorView.superDispatchTouchEvent(DecorView.java:475)
   at com.android.internal.policy.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1836)
   at android.app.Activity.dispatchTouchEvent(Activity.java:3404)
   at androidx.appcompat.view.WindowCallbackWrapper.dispatchTouchEvent(WindowCallbackWrapper.java:69)
   at com.android.internal.policy.DecorView.dispatchTouchEvent(DecorView.java:433)
   at android.view.View.dispatchPointerEvent(View.java:12755)
   at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:5150)
   at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:4953)
   at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4470)
   at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4523)
   at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4489)
   at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4629)
   at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4497)
   at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:4686)
   at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4470)
   at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4523)
   at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4489)
   at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4497)
   at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4470)
   at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:7192)
   at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:7126)
   at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:7087)
   at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:7295)
   at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:193)
   at android.view.InputEventReceiver.nativeConsumeBatchedInputEvents(Native Method)
   at android.view.InputEventReceiver.consumeBatchedInputEvents(InputEventReceiver.java:184)
   at android.view.ViewRootImpl.doConsumeBatchedInput(ViewRootImpl.java:7266)
   at android.view.ViewRootImpl$ConsumeBatchedInputRunnable.run(ViewRootImpl.java:7318)
   at android.view.Choreographer$CallbackRecord.run(Choreographer.java:949)
   at android.view.Choreographer.doCallbacks(Choreographer.java:761)
   at android.view.Choreographer.doFrame(Choreographer.java:690)
   at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:935)
   at android.os.Handler.handleCallback(Handler.java:873)
   at android.os.Handler.dispatchMessage(Handler.java:99)
   at android.os.Looper.loop(Looper.java:193)
   at android.app.ActivityThread.main(ActivityThread.java:6912)
   at java.lang.reflect.Method.invoke(Native Method)
   at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:860)

使用CameraX.unbindAll() 和 CameraX.bindToLifecycle()**:**的错误日志

   E/Legacy-CameraDevice-JNI: getNativeWindow: Surface had no valid native window.
   E/Legacy-CameraDevice-JNI: LegacyCameraDevice_nativeDetectSurfaceDimens: Could not retrieve native window from surface.

--------- beginning of crash
   2019-05-09 16:49:29.155 31123-31144/com.android.example.cameraxbasic E/AndroidRuntime: FATAL EXCEPTION: CameraX-
Process: com.android.example.cameraxbasic, PID: 31123
java.lang.IllegalArgumentException: Surface was abandoned
    at android.hardware.camera2.utils.SurfaceUtils.getSurfaceSize(SurfaceUtils.java:84)
    at android.hardware.camera2.params.OutputConfiguration.<init>(OutputConfiguration.java:260)
    at android.hardware.camera2.params.OutputConfiguration.<init>(OutputConfiguration.java:145)
    at android.hardware.camera2.impl.CameraDeviceImpl.createCaptureSession(CameraDeviceImpl.java:518)
    at androidx.camera.camera2.impl.CaptureSession.open(CaptureSession.java:196)
    at androidx.camera.camera2.impl.Camera.openCaptureSession(Camera.java:535)
    at androidx.camera.camera2.impl.Camera$StateCallback.onOpened(Camera.java:743)
    at androidx.camera.core.CameraDeviceStateCallbacks$ComboDeviceStateCallback.onOpened(CameraDeviceStateCallbacks.java:99)
    at android.hardware.camera2.impl.CameraDeviceImpl$1.run(CameraDeviceImpl.java:152)
    at android.os.Handler.handleCallback(Handler.java:873)
    at android.os.Handler.dispatchMessage(Handler.java:99)
    at android.os.Looper.loop(Looper.java:193)
    at android.os.HandlerThread.run(HandlerThread.java:65)
 Caused by: android.hardware.camera2.legacy.LegacyExceptionUtils$BufferQueueAbandonedException
    at android.hardware.camera2.legacy.LegacyExceptionUtils.throwOnError(LegacyExceptionUtils.java:73)
    at android.hardware.camera2.legacy.LegacyCameraDevice.getSurfaceSize(LegacyCameraDevice.java:606)
    at android.hardware.camera2.utils.SurfaceUtils.getSurfaceSize(SurfaceUtils.java:82)
    at android.hardware.camera2.params.OutputConfiguration.<init>(OutputConfiguration.java:260) 
    at android.hardware.camera2.params.OutputConfiguration.<init>(OutputConfiguration.java:145) 
    at android.hardware.camera2.impl.CameraDeviceImpl.createCaptureSession(CameraDeviceImpl.java:518) 
    at androidx.camera.camera2.impl.CaptureSession.open(CaptureSession.java:196) 
    at androidx.camera.camera2.impl.Camera.openCaptureSession(Camera.java:535) 
    at androidx.camera.camera2.impl.Camera$StateCallback.onOpened(Camera.java:743) 
    at androidx.camera.core.CameraDeviceStateCallbacks$ComboDeviceStateCallback.onOpened(CameraDeviceStateCallbacks.java:99) 
    at android.hardware.camera2.impl.CameraDeviceImpl$1.run(CameraDeviceImpl.java:152) 
    at android.os.Handler.handleCallback(Handler.java:873) 
    at android.os.Handler.dispatchMessage(Handler.java:99) 
    at android.os.Looper.loop(Looper.java:193) 
    at android.os.HandlerThread.run(HandlerThread.java:65) 


--------- beginning of system

Answer 1

最后，我们得到了CameraX中的Zoom。请检查以下两种方式，您可以用来缩放相机的预览。

夹点放大：

val scaleGestureDetector = ScaleGestureDetector(context, listener)

cameraTextureView.setOnTouchListener { _, event ->
    scaleGestureDetector.onTouchEvent(event)
    return@setOnTouchListener true
}

val listener = object : ScaleGestureDetector.SimpleOnScaleGestureListener() {
    override fun onScale(detector: ScaleGestureDetector): Boolean {
        val scale = cameraInfo.zoomRatio.value * detector.scaleFactor
        cameraControl.setZoomRatio(scale)
        return true
    }
}

幻灯片缩放(使用查找栏)：

zoomSeekBar.setOnSeekBarChangeListener(object : SeekBar.OnSeekBarChangeListener {        
    override fun onProgressChanged(seekBar: SeekBar?, progress: Int, fromUser: Boolean) {
        cameraControl.setLinearZoom(progress / 100.toFloat())
    }

    override fun onStartTrackingTouch(seekBar: SeekBar?) {}

    override fun onStopTrackingTouch(seekBar: SeekBar?) {}
})

使用下面的cameraControl**:**获取

val cameraControl = CameraX.getCameraControl(lensFacing)

代码参考链接： https://github.com/Pinkal7600/camera-samples/tree/master/CameraXBasic

Answer 2

要使缩放正常工作，还需要在bindToLifecycle()之后调用缩放()。还请注意，缩放()接受位于传感器坐标中的Rect。有关更多详细信息，请参阅这里。

您还可能需要使用camera2 API来获取传感器有源阵列和相机id (请使用具有正确LENS_FACING的第一个LENS_FACING)。我们知道这是很多工作，所以我们正在开发一个新的更高级别的缩放API，它更容易使用，也更简单。

Answer 3

看起来这个错误与预览缩放：java.lang.IllegalArgumentException: Exceeded max simultaneously bound image capture use cases.无关

这表明您在解除绑定之前多次调用CameraX.bindToLifecycle(imageCapture)，这就是导致崩溃的原因。我还建议使用配置生成器而不是getDefaultUseCaseConfig，因为它们更显着，更易于阅读，而getDefaultUseCaseConfig是一个隐藏的API。

有关更多细节，请参阅官方样品的示例实现和文档。