Honestly, I was in the same boat as you. I've got a C++ Library that I wanted to connect to a graphing utility. I ended up using Boost Python and matplotlib. It was the best one that I could find.
As a side note: I was also wary of licensing. matplotlib and the boost libraries can be integrated into proprietary applications.
Here's an example of the code that I used:
#include <boost/python.hpp>
#include <pygtk/pygtk.h>
#include <gtkmm.h>
using namespace boost::python;
using namespace std;
// This is called in the idle loop.
bool update(object *axes, object *canvas) {
static object random_integers = object(handle<>(PyImport_ImportModule("numpy.random"))).attr("random_integers");
axes->attr("scatter")(random_integers(0,1000,1000), random_integers(0,1000,1000));
axes->attr("set_xlim")(0,1000);
axes->attr("set_ylim")(0,1000);
canvas->attr("draw")();
return true;
}
int main() {
try {
// Python startup code
Py_Initialize();
PyRun_SimpleString("import signal");
PyRun_SimpleString("signal.signal(signal.SIGINT, signal.SIG_DFL)");
// Normal Gtk startup code
Gtk::Main kit(0,0);
// Get the python Figure and FigureCanvas types.
object Figure = object(handle<>(PyImport_ImportModule("matplotlib.figure"))).attr("Figure");
object FigureCanvas = object(handle<>(PyImport_ImportModule("matplotlib.backends.backend_gtkagg"))).attr("FigureCanvasGTKAgg");
// Instantiate a canvas
object figure = Figure();
object canvas = FigureCanvas(figure);
object axes = figure.attr("add_subplot")(111);
axes.attr("hold")(false);
// Create our window.
Gtk::Window window;
window.set_title("Engineering Sample");
window.set_default_size(1000, 600);
// Grab the Gtk::DrawingArea from the canvas.
Gtk::DrawingArea *plot = Glib::wrap(GTK_DRAWING_AREA(pygobject_get(canvas.ptr())));
// Add the plot to the window.
window.add(*plot);
window.show_all();
// On the idle loop, we'll call update(axes, canvas).
Glib::signal_idle().connect(sigc::bind(&update, &axes, &canvas));
// And start the Gtk event loop.
Gtk::Main::run(window);
} catch( error_already_set ) {
PyErr_Print();
}
}
