how do you plot graphs in opencv projects?

edit

i tried to understand usage of Plot2d class maybe the code below will be useful for someone who want to try.

#include <opencv2/highgui.hpp>
#include <opencv2/plot.hpp>

using namespace cv;

int main(int argc, char** argv)
{
   // Plot data must be a 1xN or Nx1 matrix.
   // Plot data type must be double (CV_64F) 
    Mat data( 30, 1, CV_64F );
    randu( data, 0, 500 ); // random values

    Mat plot_result;

    Ptr<plot::Plot2d> plot = plot::Plot2d::create(data);
    plot->setPlotBackgroundColor( Scalar( 50, 50, 50 ) );
    plot->setPlotLineColor( Scalar( 50, 50, 255 ) );
    plot->render( plot_result );

    imshow( "plot", plot_result );
    waitKey();

    plot->setPlotLineColor( Scalar( 50, 255, 255 ) );
    data = data / 3;
    plot->render( plot_result );

    imshow( "plot", plot_result );
    waitKey();

    plot->setPlotGridColor( Scalar( 255, 0, 255 ) );
    data = data * 4;
    plot->render( plot_result );

    imshow( "plot", plot_result );
    waitKey();

    plot->setPlotTextColor( Scalar( 255, 0, 0 ) );
    randu( data, 100, 400 );
    plot->render( plot_result );

    imshow( "plot", plot_result );
    waitKey();

    return 0;
}

sample java code

import org.opencv.core.Core;
import org.opencv.core.Scalar;
import org.opencv.core.CvType;
import org.opencv.core.Mat;
import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.plot.Plot2d;
public class test
{
   public static void main( String[] args )
   {
      System.loadLibrary( Core.NATIVE_LIBRARY_NAME );
      Mat data = new Mat(1, 20, CvType.CV_64F);
      Core.randu(data, 1, 10);
      Plot2d plot = Plot2d.create(data);
      Mat mplot = new Mat();
      plot.setPlotLineColor(new Scalar(0,0,255));
      plot.render(mplot);
      Imgcodecs.imwrite("e:/test.png", mplot);
   }
}

You could try Profactor CvPlot https://github.com/Profactor/cv-plot. (I am the developer). It is very easy to integrate, purely opencv based and can be extended with custom drawables. This is how you can plot to a cv::Mat or show a diagram with an interactive viewer:

#include <CvPlot/cvplot.h>
std::vector<double> x(20*1000), y1(x.size()), y2(x.size()), y3(x.size());
for (size_t i = 0; i < x.size(); i++) {
    x[i] = i * CV_2PI / x.size();
    y1[i] = std::sin(x[i]);
    y2[i] = y1[i] * std::sin(x[i]*50);
    y3[i] = y2[i] * std::sin(x[i]*500);
}
auto axes = CvPlot::makePlotAxes();
axes.create<CvPlot::Series>(x, y3, "-g");
axes.create<CvPlot::Series>(x, y2, "-b");
axes.create<CvPlot::Series>(x, y1, "-r");

//plot to a cv::Mat
cv::Mat mat = axes.render(300, 400);

//or show with interactive viewer
CvPlot::show("mywindow", axes);

You may also want to try Leonardvandriel's cvplot. It works similar but cannot be extended with custom drawables.

Try this cvplot framework. You can plot in real time and and have multiple plots in a single window.