text: # Copyright 2017 The TensorFlow Authors. All Rights Reserved.
  #
  # Licensed under the Apache License, Version 2.0 (the "License");
  # you may not use this file except in compliance with the License.
  # You may obtain a copy of the License at
  #
  #     http://www.apache.org/licenses/LICENSE-2.0
  #
  # Unless required by applicable law or agreed to in writing, software
  # distributed under the License is distributed on an "AS IS" BASIS,
  # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  # ==============================================================================
  
  """A function to build an object detection box coder from configuration."""
  from object_detection.box_coders import faster_rcnn_box_coder
  from object_detection.box_coders import keypoint_box_coder
  from object_detection.box_coders import mean_stddev_box_coder
  from object_detection.box_coders import square_box_coder
  from object_detection.protos import box_coder_pb2
  
  
  def build(box_coder_config):
    """Builds a box coder object based on the box coder config.
  
    Args:
      box_coder_config: A box_coder.proto object containing the config for the
        desired box coder.
  
    Returns:
      BoxCoder based on the config.
  
    Raises:
      ValueError: On empty box coder proto.
    """
    if not isinstance(box_coder_config, box_coder_pb2.BoxCoder):
      raise ValueError('box_coder_config not of type box_coder_pb2.BoxCoder.')
  
    if box_coder_config.WhichOneof('box_coder_oneof') == 'faster_rcnn_box_coder':
      return faster_rcnn_box_coder.FasterRcnnBoxCoder(scale_factors=[
          box_coder_config.faster_rcnn_box_coder.y_scale,
          box_coder_config.faster_rcnn_box_coder.x_scale,
          box_coder_config.faster_rcnn_box_coder.height_scale,
          box_coder_config.faster_rcnn_box_coder.width_scale
      ])
    if box_coder_config.WhichOneof('box_coder_oneof') == 'keypoint_box_coder':
      return keypoint_box_coder.KeypointBoxCoder(
          box_coder_config.keypoint_box_coder.num_keypoints,
          scale_factors=[
              box_coder_config.keypoint_box_coder.y_scale,
              box_coder_config.keypoint_box_coder.x_scale,
              box_coder_config.keypoint_box_coder.height_scale,
              box_coder_config.keypoint_box_coder.width_scale
          ])
    if (box_coder_config.WhichOneof('box_coder_oneof') ==
        'mean_stddev_box_coder'):
      return mean_stddev_box_coder.MeanStddevBoxCoder()
    if box_coder_config.WhichOneof('box_coder_oneof') == 'square_box_coder':
      return square_box_coder.SquareBoxCoder(scale_factors=[
          box_coder_config.square_box_coder.y_scale,
          box_coder_config.square_box_coder.x_scale,
          box_coder_config.square_box_coder.length_scale
      ])
    raise ValueError('Empty box coder.')
  