okermorgant / slider_publisher

Generic slider-based GUI to publish any kind of message

slider_publisher

This package proposes a slider-based publisher node similar to the joint_state_publisher, but that can publish any type of message.

Several examples are given:

• roslaunch example.launch for timestamped Twist (cmd_vel)
• roslaunch example.launch file:=Twist.yaml for non-timestamped Twist
• roslaunch example.launch file:=VelPose.yaml for 2 topics (Twist + Pose)
• roslaunch example.launch file:=MultiArray.yaml for a topic with 4 floats
• roslaunch gazebo_service.launch for a service call (uses gazebo_msgs)

Only numerical types or their derivatives can be publisher (ie there is no text input to change such value on-the-fly). Array-based messages are also possible for numerical values.

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 to specify it is a message)
    key_as_in_gui:                        (vx)
        to: corresponding_message_field   (linear.x)
        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.

Parameters

• ~rate (default 10): the rate of publication

slider_publisher's Issues

refactor: Any chance to drop dependeny on SymPy?

slider_publisher/slider_publisher

Line 49 in 945919d

out = float(eval_expr(val))

I was trying out you package and I am wondering if there is a possibility to replace line 49 with code that is not dependent on SymPy. Having to install SymPy to run your package imposes a hefty overhead that might not be required.

I personally droped "eval_expr" and I seems to work well (but did not test extensively)
For instance:

def robust_eval(val):
    if type(val) in (list,tuple):
        return [robust_eval(v) for v in val]
    if type(val) == str:    # evaluate only if can be converted to float
        try:
            # out = float(eval_expr(val))
            out = float(val)
            return out
        except:
            return val
    return float(val)