> Maybe you can elaborate what exactly you are trying to achieve when I use `cv_bridge` in ros2 , the img_msg is turned into `list` in python , but the `cv_bridge` needs a `byte` type when transform the `img_msg.data` into `cv2` img type . (the `img_msg.data` is `uint8 []` and is turned into `list` after transform) So we rewrite the `genorator_py` in `rosidl` to make the uint8 turn into `byte` type , and it works well but to avoid effecting other algorithm which using uint8 as well in pyhton , we want to create a `new_uint8[]` for a new msg type like `new_imagemsg` so that we don't need to transform all `uint8[]` to bytes , but only in some special situations (like using cv_bridge) , we can use the new message type and get the byte type instead of list . and other algorithm can still receive the `image_msg.data` as `list` type So i just want to know whether this idea can work , and how to make it . I'm trying to rewrite the python-end in rosidl and build a new primitive type maybe use dtype() ? and a new msg_type and try to analyze the type --- [Visit Topic](https://discourse.ros.org/t/discussion-about-how-to-add-a-new-primitive-types-to-rosidl-msg/4607/3) or reply to this email to respond. If you do not want to receive messages from ros-users please use the unsubscribe link below. If you use the one above, you will stop all of ros-users from receiving updates. ______________________________________________________________________________ ros-users mailing list ros-users@lists.ros.org http://lists.ros.org/mailman/listinfo/ros-users Unsubscribe: