android - Camera Source (Google Mobile Vision) 在某些设备上返回旋转图像

Question

我有 Google Mobile Vision 的开源代码 - CameraSource，这是我点击照片时调用的方法:cameraSource.takePicture();

在CameraSource.java的开源版本中，确定屏幕方向的方法是stock one:

private void setRotation(Camera camera, Camera.Parameters parameters, int cameraId) {
        WindowManager windowManager =
                (WindowManager) mContext.getSystemService(Context.WINDOW_SERVICE);
        int degrees = 0;
        int rotation = windowManager.getDefaultDisplay().getRotation();
        switch (rotation) {
            case Surface.ROTATION_0:
                degrees = 0;
                break;
            case Surface.ROTATION_90:
                degrees = 90;
                break;
            case Surface.ROTATION_180:
                degrees = 180;
                break;
            case Surface.ROTATION_270:
                degrees = 270;
                break;
            default:
                Log.e(TAG, "Bad rotation value: " + rotation);
        }

        CameraInfo cameraInfo = new CameraInfo();
        Camera.getCameraInfo(cameraId, cameraInfo);

        int angle;
        int displayAngle;
        if (cameraInfo.facing == CameraInfo.CAMERA_FACING_FRONT) {
            angle = (cameraInfo.orientation + degrees) % 360;
            displayAngle = (360 - angle) % 360; // compensate for it being mirrored
        } else {  // back-facing
            angle = (cameraInfo.orientation - degrees + 360) % 360;
            displayAngle = angle;
        }

        // This corresponds to the rotation constants in {@link Frame}.
        mRotation = angle / 90;

        camera.setDisplayOrientation(displayAngle);
        parameters.setRotation(angle);
    }

这里的displayAngle和angle对于三星、联想和Yuntab H8都是一样的。但是为 backCamera 返回的位图在每个设备中的旋转方式不同。我必须为每个设备手动旋转位图(三星:90，联想:0 和 Yuntab:180)

我的要求是 onPictureTaken 应该返回一个与当前显示方向匹配的位图。我很长时间以来一直在研究这个问题，但仍然必须想办法解决这个问题。下面是我的 onPicturetaken() (拍照后调用):

  @Override
        public void onPictureTaken(byte[] bytes) {
            try {
                BitmapFactory.Options options = new BitmapFactory.Options();
                options.inSampleSize = 2;
                bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length, currentCameraId == 0 ? options : null);
            }catch (Exception ex){
                ex.printStackTrace();
                Log.e("PictureTaken",ex.toString());
        }
    };

Answer 1

当图像已保存在设备中时，您应该旋转图像。

然后您可以旋转它以匹配拍摄照片时的位置。

示例代码(它可能需要一些清理和改进，但它可以工作...):

计算图像旋转的方法:

private static int rotationNeeded(String path) {
    try {
        File file = new File(path);

        if (!file.getName().contains(".jpg")) {
            return 0;
        }

        ExifInterface exif = new ExifInterface(file.getAbsolutePath());
        int orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL);

        if (orientation == ExifInterface.ORIENTATION_ROTATE_270) {
            return 270;
        }

        if (orientation == ExifInterface.ORIENTATION_ROTATE_180) {
            return 180;
        }

        if (orientation == ExifInterface.ORIENTATION_ROTATE_90) {
            return 90;
        }
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
    return 0;
}

对图像应用所需的旋转:

public static void rotateImage(String filePath) {
    try {
        BitmapFactory.Options options = new BitmapFactory.Options();
        options.inSampleSize = 2;
        Bitmap bitmap = BitmapFactory.decodeFile(filePath, options);

        //check image rotation
        int rotate = rotationNeeded(filePath);
        if (rotate != 0) {
            //rotate image if needed
            Matrix matrix = new Matrix();
            matrix.postRotate(rotate);
            Bitmap rotatedImage = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(),
                    bitmap.getHeight(), matrix, true);

            bitmap.recycle();
            bitmap = rotatedImage;

            //save image
            byte[] dataPicture = bao.toByteArray();
            FileOutputStream fos = new FileOutputStream(filePath);
            fos.write(dataPicture);
            fos.flush();
            fos.close();
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}