Free easy way to draw graphs and charts in C++?


Question

I am doing a little exploring simulation and I want to show the graphs to compare the performance among the algorithms during run-time.

What library comes to your mind? I highly prefer those that come small as I'd love if it's easy for my instructor to compile my code. I've checked gdchart but it seems to be too heavy. I just want a simple x-y sort of timeline graph.

Google chart is of course out of the question, in case you've read this similar question.


Related post Scatter Plots in C++.

1
26
10/28/2017 2:21:18 PM

Accepted Answer

My favourite has always been gnuplot. It's very extensive, so it might be a bit too complex for your needs though. It is cross-platform and there is a C++ API.

15
12/8/2015 1:22:04 PM

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();
    }
}

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