Plotting widgets for Linux apps
This summer, I've been working for the biorobotics lab at Case Western. Technically, I'm under the supervision and mostly the pay of the biology side, but my work relates more to the robotics side. German researchers recently developed software that uses a state machine of sorts to model the neural system that controls one insect leg. Our biologists would like to use this model to test some of their theories about how that neural system works, so we're building a robotic leg which will be controlled by a computer using software adapted from the German system.
My job is to provide a nice graphical interface with which biologists can alter thresholds in the model. The sticking point, in recent weeks, has been their desire for real-time plotting of data coming back off the leg.
Since the control computer will be running Real-Time Linux to communicate with the robot on a timely basis, I started off using GTK+ to build the interface. GTK+ has several advantages: A big one is that it's easy to understand and program (unlike, say, the Win32 API). The Glade UI-building tool, and its associated library for automatic interpretation of the XML it generates, add up to a big plus too.
However, if you want a graph-plotting widget and you don't want to write it yourself from scratch, you have to go looking for add-on libraries. GtkExtra seems to be the popular choice for such needs, but its behavior has been extremely flaky on my computer from Day 1. (Much as I love open-source software, I find that this kind of twitchiness is one of its real lurking dangers.) I've managed to get one application -- not the one I'm working on -- to compile with GtkExtra, but it refuses to run, citing linked-library problems.
GtkExtra has proved so unbelievably intractable that I've been slowly converting over to the KDE libraries and KDevelop as an alternate means of building the application. KDE, I find, isn't nearly as simple to work with once you're into the nuts and bolts of it, but on the other hand, C++ is a much friendlier language for me than C: Since I learned C++ first, I spend most of my time in C crashing around cursing the lack of classes and wishing I had the STL.
Like GTK, KDE libraries don't include a plotting widget, but there's another poorly-documented add-on for those of us crazy enough to need to tackle something like that: Kde-edu includes a plotting widget. Whether I'll be able to get THIS one to play nicely remains to be seen.
Comments
Is this for the big roach bot? Or one of the smaller guys? (I'm very interested in the biorobotics stuff, especially the wegs and neural net research)
It's actually not connected to any of the major projects (RV, Whegs, etc.) in the biorobotics lab, at least for now -- we're just building a robotic leg and setting up the computer to move it, using a different control model than they have before. It's more of a tool for the biologists to test their ideas than a project for the engineers to fritz around with. I'm not sure what further development they may or may not be planning for this doodad.