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Transforming your own datatypes

Description: This tutorial explains which methods you need to implement to make tf2 transform your own datatypes.

Tutorial Level: ADVANCED

Requirements for a Library Port


Implement the following functions for each datatype:

   1 namespace tf2
   2 {
   3 /**\brief The templated function expected to be able to do a transform
   4  *
   5  * This is the method which tf2 will use to try to apply a transform for any given datatype.   
   6  * \param data_in The data to be transformed.
   7  * \param data_out A reference to the output data.  Note this can point to data in and the method should be mutation safe.
   8  * \param transform The transform to apply to data_in to fill data_out.  
   9  * 
  10  * This method needs to be implemented by client library developers
  11  */
  12 template <class T>
  13   void doTransform(const T& data_in, T& data_out, const geometry_msgs::TransformStamped& transform);
  15 /**\brief Get the timestamp from data 
  16  * \param t The data input.
  17  * \return The timestamp associated with the data. 
  18  */
  19 template <class T>
  20   const ros::Time& getTimestamp(const T& t);
  22 /**\brief Get the frame_id from data 
  23  * \param t The data input.
  24  * \return The frame_id associated with the data. 
  25  */
  26 template <class T>
  27   const std::string& getFrameId(const T& t);
  28 }


Python implementation for PointStamped

   1 def do_transform_point(point, transform):
   2     p = transform_to_kdl(transform) * PyKDL.Vector(point.point.x, point.point.y, point.point.z)
   3     res = PointStamped()
   4     res.point.x = p[0]
   5     res.point.y = p[1]
   6     res.point.z = p[2]
   7     res.header = transform.header
   8     return res
   9 tf2_py.TransformRegistration().add(PointStamped, do_transform_point)

Wiki: tf2/Tutorials/Transforming your own datatypes (last edited 2022-10-06 16:53:55 by ShaneLoretz)