Рисование холста на камеру

Question

Когда я пытаюсь создать кадр сканера, например, [] используя холст для захвата документов, камера останавливается, а фон превращается в черный, и отображается только холст.

Также пробовал просмотр текстуры с помощью camera2 api, но стал белым экранная камера останавливает рендеринг, и видна только рамка холста

Если вы можете оказать мне какую-либо помощь, в основном для просмотра текстур, а также, что может быть лучше

public class CameraActivity extends AppCompatActivity{ 

TextView testView;
Camera camera;
SurfaceView surfaceView;
SurfaceHolder surfaceHolder;

private RenderThread mThread;

Camera.PictureCallback rawCallback;
Camera.ShutterCallback shutterCallback;
Camera.PictureCallback jpegCallback;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_camera);

    surfaceView = findViewById(R.id.surfaceView);

    assert surfaceView != null;
     surfaceView.getHolder().addCallback(new SurfaceHolder.Callback() {
        @Override
        public void surfaceCreated(SurfaceHolder holder) {
            surfaceHolder = holder;
            surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

            try {
                // open the camera

                camera = Camera.open();
            } catch (RuntimeException e) {
                // check for exceptions
                System.err.println(e);
                return;
            }
            Camera.Parameters param;
            param = camera.getParameters();

            param.setPreviewSize(352, 288);
            camera.setParameters(param);
            try {

                camera.setPreviewDisplay(surfaceHolder);

                camera.startPreview();
            } catch (Exception e) {
                System.err.println(e);
                return;
            }
        }

        @Override
        public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
            refreshCamera();
        }

        @Override
        public void surfaceDestroyed(SurfaceHolder holder) {
            camera.stopPreview();
            camera.release();
            camera = null;
        }
    });

    jpegCallback = new Camera.PictureCallback() {
        public void onPictureTaken(byte[] data, Camera camera) {
            FileOutputStream outStream = null;
            try {
                outStream = new FileOutputStream(String.format("/sdcard/%d.jpg", System.currentTimeMillis()));
                outStream.write(data);
                outStream.close();
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
            }
            Toast.makeText(getApplicationContext(), "Picture Saved", Toast.LENGTH_SHORT).show();
            refreshCamera();
        }
    };
}

public void captureImage(View v) throws IOException {
    //take the picture
    camera.takePicture(null, null, jpegCallback);
}

public void refreshCamera() {
    if (surfaceHolder.getSurface() == null) {
        // preview surface does not exist
        return;
    }

    try {
        camera.stopPreview();
    } catch (Exception e) {
    }


    try {
        camera.setPreviewDisplay(surfaceHolder);
        camera.startPreview();

    } catch (Exception e) {
       e.printStackTrace();
    }
}


private class RenderThread extends Thread {
    private volatile boolean mRunning = true;

    @Override
    public void run() {
        Paint mPaint = new Paint();
        System.out.println("Running canvas ...............................");
        final Canvas canvas = surfaceHolder.lockCanvas();
        try {
            if(canvas != null) {
                canvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);

                mPaint.setStyle(Paint.Style.STROKE);
                mPaint.setColor(Color.BLUE);
                mPaint.setStrokeWidth(10);

                Path path = new Path();

                canvas.drawLine(250, 250, 400, 250, mPaint);
                canvas.drawLine(255, 250, 255, 400, mPaint);

                canvas.drawLine(750, 250, 900, 250, mPaint);
                canvas.drawLine(895, 250, 895, 400, mPaint);


                canvas.drawLine(250, 900, 400, 900, mPaint);
                canvas.drawLine(255, 900 - 150, 255, 900, mPaint);

                canvas.drawLine(750, 900, 900, 900, mPaint);
                canvas.drawLine(895, 900 - 150, 895, 900, mPaint);


                canvas.drawPath(path, mPaint);
            }

        } finally {
            surfaceHolder.unlockCanvasAndPost(canvas);
        }
    }
    public void stopRendering() {
        interrupt();
        mRunning = false;
    }
 }}