如何在Firebase ML kit Android中正确绘制检测到的人脸上的包围框？

implementation 'com.google.firebase:firebase-ml-vision:24.0.3'
implementation 'com.google.android.gms:play-services-mlkit-face-detection:16.1.3'

FirebaseVisionFaceDetectorOptions options =
    new FirebaseVisionFaceDetectorOptions.Builder()
        .setClassificationMode(FirebaseVisionFaceDetectorOptions.ALL_CLASSIFICATIONS)
        .build();

FirebaseVisionFaceDetector detector = FirebaseVision.getInstance()
    .getVisionFaceDetector(options);

// 在Camera.PreviewCallback中的回调方法中获取相机预览帧的图像数据
@Override
public void onPreviewFrame(byte[] data, Camera camera) {
    // 获取相机预览帧的图像数据
    FirebaseVisionImage image = FirebaseVisionImage.fromByteArray(data, /* image rotation */);

    // 进行人脸检测
    Task<List<FirebaseVisionFace>> result = detector.detectInImage(image)
        .addOnSuccessListener(new OnSuccessListener<List<FirebaseVisionFace>>() {
            @Override
            public void onSuccess(List<FirebaseVisionFace> faces) {
                // 在成功回调中处理人脸检测结果
                for (FirebaseVisionFace face : faces) {
                    // 获取人脸的位置信息
                    Rect bounds = face.getBoundingBox();

                    // 绘制包围框
                    drawBoundingBox(bounds);
                }
            }
        })
        .addOnFailureListener(new OnFailureListener() {
            @Override
            public void onFailure(@NonNull Exception e) {
                // 处理人脸检测失败的情况
            }
        });
}

private void drawBoundingBox(Rect bounds) {
    // 获取相机预览界面的宽度和高度
    int viewWidth = cameraPreview.getWidth();
    int viewHeight = cameraPreview.getHeight();

    // 进行坐标转换
    int left = (int) (bounds.left * viewWidth);
    int top = (int) (bounds.top * viewHeight);
    int right = (int) (bounds.right * viewWidth);
    int bottom = (int) (bounds.bottom * viewHeight);

    // 在相机预览界面上绘制人脸包围框
    canvas.drawRect(left, top, right, bottom, paint);
    cameraPreview.invalidate(); // 更新界面
}