Welcome to matplotlib-cpp, possibly the simplest C++ plotting library. It is built to resemble the plotting API used by Matlab and matplotlib.
Complete minimal example:
#include "matplotlibcpp.h"
namespace plt = matplotlibcpp;
int main() {
plt::plot({1,3,2,4});
plt::show();
}g++ minimal.cpp -std=c++11 -I/usr/include/python2.7 -lpython2.7
Result:
A more comprehensive example:
#include "matplotlibcpp.h"
#include <cmath>
namespace plt = matplotlibcpp;
int main()
{
// Prepare data.
int n = 5000;
std::vector<double> x(n), y(n), z(n), w(n,2);
for(int i=0; i<n; ++i) {
x.at(i) = i*i;
y.at(i) = sin(2*M_PI*i/360.0);
z.at(i) = log(i);
}
// Set the size of output image to 1200x780 pixels
plt::figure_size(1200, 780);
// Plot line from given x and y data. Color is selected automatically.
plt::plot(x, y);
// Plot a red dashed line from given x and y data.
plt::plot(x, w,"r--");
// Plot a line whose name will show up as "log(x)" in the legend.
plt::named_plot("log(x)", x, z);
// Set x-axis to interval [0,1000000]
plt::xlim(0, 1000*1000);
// Add graph title
plt::title("Sample figure");
// Enable legend.
plt::legend();
// Save the image (file format is determined by the extension)
plt::save("./basic.png");
}g++ basic.cpp -I/usr/include/python2.7 -lpython2.7
Result:
Alternatively, matplotlib-cpp also supports some C++11-powered syntactic sugar:
#include <cmath>
#include "matplotlibcpp.h"
using namespace std;
namespace plt = matplotlibcpp;
int main()
{
// Prepare data.
int n = 5000; // number of data points
vector<double> x(n),y(n);
for(int i=0; i<n; ++i) {
double t = 2*M_PI*i/n;
x.at(i) = 16*sin(t)*sin(t)*sin(t);
y.at(i) = 13*cos(t) - 5*cos(2*t) - 2*cos(3*t) - cos(4*t);
}
// plot() takes an arbitrary number of (x,y,format)-triples.
// x must be iterable (that is, anything providing begin(x) and end(x)),
// y must either be callable (providing operator() const) or iterable.
plt::plot(x, y, "r-", x, [](double d) { return 12.5+abs(sin(d)); }, "k-");
// show plots
plt::show();
}g++ modern.cpp -std=c++11 -I/usr/include/python2.7 -lpython
Result:
Or some funny-looking xkcd-styled example:
#include "matplotlibcpp.h"
#include <vector>
#include <cmath>
namespace plt = matplotlibcpp;
int main() {
std::vector<double> t(1000);
std::vector<double> x(t.size());
for(size_t i = 0; i < t.size(); i++) {
t[i] = i / 100.0;
x[i] = sin(2.0 * M_PI * 1.0 * t[i]);
}
plt::xkcd();
plt::plot(t, x);
plt::title("AN ORDINARY SIN WAVE");
plt::save("xkcd.png");
}
g++ xkcd.cpp -std=c++11 -I/usr/include/python2.7 -lpython2.7
Result:
When working with vector fields, you might be interested in quiver plots:
#include "../matplotlibcpp.h"
namespace plt = matplotlibcpp;
int main()
{
// u and v are respectively the x and y components of the arrows we're plotting
std::vector<int> x, y, u, v;
for (int i = -5; i <= 5; i++) {
for (int j = -5; j <= 5; j++) {
x.push_back(i);
u.push_back(-i);
y.push_back(j);
v.push_back(-j);
}
}
plt::quiver(x, y, u, v);
plt::show();
}g++ quiver.cpp -std=c++11 -I/usr/include/python2.7 -lpython2.7
Result:
When working with 3d functions, you might be interested in 3d plots:
#include "../matplotlibcpp.h"
namespace plt = matplotlibcpp;
int main()
{
std::vector<std::vector<double>> x, y, z;
for (double i = -5; i <= 5; i += 0.25) {
std::vector<double> x_row, y_row, z_row;
for (double j = -5; j <= 5; j += 0.25) {
x_row.push_back(i);
y_row.push_back(j);
z_row.push_back(::std::sin(::std::hypot(i, j)));
}
x.push_back(x_row);
y.push_back(y_row);
z.push_back(z_row);
}
plt::plot_surface(x, y, z);
plt::show();
}Result:
matplotlib-cpp works by wrapping the popular python plotting library matplotlib. (matplotlib.org) This means you have to have a working python installation, including development headers. On Ubuntu:
< 8000 div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="sudo apt-get install python-matplotlib python-numpy python2.7-dev">sudo apt-get install python-matplotlib python-numpy python2.7-dev