Draw preliminary rqt_graph from topics found

[cbandera]

Hi pschillinger,

I really like your work and I think this is a very useful tool.
A nice extension to this would be the possibility to draw a preliminary graph from the topics found in the launch file.

So when I am setting up a demo launch file (and suppose every available topic is listed as a remap in the underlying launch files) wouldn't it be cool to get a direct visual feedback of whether it is going to work out the way you expect it to work?

I guess one could reuse parts of the rqt_graph plugin to draw the graph. Additionally nested namespaces and stuff has to be resolved. This could be a first step towards a "simulink-like" drag-and-connect feature for ROS nodes.

I'd be happy if you share your toughts on this with me.
~cbandera

[pschillinger]

Hey Claudio,

thanks for your feedback! :) Interesting idea to visualize topic remapping, although this does not mean everything will work out as expected, of course. I think building a graph just from remappings could raise a few issues:

• It is not possible to guarantee that it is complete (verify the assumption that every topic is listed) and cumbersome to maintain or create the first time.
• We don't know whether a node publishes or subscribes (or even both) on a listed topic.
• We don't have information whether the topic type is consistent.

So I think rqt_graph is much more useful since these issues do not arise during runtime. For simply checking if there are some unconnected subscribers, roswtf is also a helpful option.

Despite this, a good launchfile editor would definitely be nice. But that's not what rqt_launchtree is aiming for. So if you have some good ideas regarding this (simulink-like editor sounds great!) and some time, I assume it would be helpful for a lot of people. :)