slider_publisher

This packages proposes a slider-based publisher node similar to the joint_state_publisher, but that can publish any message or service.

Many examples are given, especially

• ros2 launch slider_publisher example.launch file:=BasicTypes.yaml for the 4 basic types
• ros2 launch slider_publisher example.launch file:=Twist.yaml for timestamped Twist (cmd_vel)
• ros2 launch slider_publisher example.launch file:=tf.yaml for a TF message
• ros2 launch slider_publisher example.launch file:=VelPose.yaml for 2 topics (Twist + Pose)
• ros2 launch slider_publisher example.launch file:=MultiArray.yaml for a topic with 4 floats
• ros2 launch slider_publisher add_two_ints.launch for a service call (uses demo_nodes_cpp server)

Array-based messages are also possible (nested arrays are not).

The packages reduces to a single node that has to be called with an argument leading to a YAML file with the following structure (examples corresponding to the VelPose.yaml file):

topic_to_be_published:  
    type: full message or service type    (geometry_msgs/Twist or geometry_msgs/msg/Twist)
    key_as_in_gui:                        (vx, can also be the message field)
        to: corresponding_message_field   (linear.x if not used as the key or not unique field)
        min: slider minimum value         (-1)
        max: slider maximum value         (+1)  
        default: slider default value     (if not: (min+max)/2)
    other_key:  
        ...
other_topic_to_be_published:  
    type...

Hard-coded numeric values (bounds / constant values in messages) can be defined using fractions of pi.

3D rotations (ie quaternions) can be parameterized as roll / pitch / yaw (see RPY.yaml). While these fields are of course not part of a Quaternion message, the corresponding 3D rotation will be built and published.

If the type is a service interface then the corresponding slider will call the service, after waiting for the server.

Input controls

Input will rely either on a checkbox (Bool type) or a text input.

• Numeric types: if min/max values are provided, a slider will also be available
• All types: if the default value is a list, a combobox will be used for the input, the first element of the list being the defalut value (see e.g. tf.yaml example)

Parameters

• config (string): this parameter has the same effect as the raw file argument, that is the path to the YAML configuration file
• rate (double): publication rate (0-100 Hz)