Plotting Data using Matplotlib from C++

I had to write some code in C++ where I wanted to plot the results of a signal processing function.
The existing C++ plotting libraries had quite a learning curve, and I was already familiar with Python's Matplotlib, so I didn't want to learn an entirely new library.
I then found matplotlib-cpp, C++ bindings for Matplotlib. It worked fine, but was quite limited.
However, that gave me the idea to use pybind11 to call Python Matplotlib code from my C++ applications.

The results are great. The C++ code just does all of its calculations, starts the Python interpreter, and passes the data to be plotted to a piece of Python code that uses Matplotlib to display the data.

This repository is a simple template that I use myself when I start a new project where I want to plot data from C++.
It contains a very simple C++ example program and a CMakeLists.txt file that builds the application.
There are also build tasks for Visual Studio Code, which I use as my main editor.

Installing the Dependencies

To build and run the example, you need a the usual tools: a compiler, make, cmake.

sudo apt install g++ make cmake

You also need Python 3, of course. Either install them through the repositories:

sudo apt install python3-dev python3-pip

Or if you want the latest Python version, check out these instructions on how to build it yourself: building Python 3 from source

You'll also need Matplotlib for the plots:

python3 -m pip install --user matplotlib

Next, install pybind11. You can install it system-wide or for your user only.

System-wide

cd /tmp
git clone https://github.com/pybind/pybind11 --depth=1
mkdir pybind11/build && cd pybind11/build
cmake .. -DPYBIND11_TEST=OFF
sudo make install

Local

cd /tmp
git clone https://github.com/pybind/pybind11 --depth=1
mkdir pybind11/build && cd pybind11/build
cmake .. -DPYBIND11_TEST=OFF -DCMAKE_INSTALL_PREFIX=$HOME/.local
make install
echo "export CMAKE_PREFIX_PATH=\$HOME/.local/lib/cmake" >> ~/.profile
source ~/.profile

Finally, just clone this repository:

cd
git clone https://github.com/tttapa/Pybind11-Matplotlib-Cpp

Building and Running the Example using the Command Line

Create a build directory, and run CMake. You can specify the path to your Python executable if you want to use a specific one, otherwise, just use which to determine the default one.

cd Pybind11-Matplotlib-Cpp
mkdir build && cd build
cmake .. -DPYTHON_EXECUTABLE=`which python3`

Next, simply run Make to build:

make

Finally, run the application:

./main

You should see a Matplotlib plot opening.

Building and Running the Example using Visual Studio Code

I also included some build tasks for Visual Studio Code that you can use.
To build the application in VSCode, open this folder using Ctrl+K Ctrl+O, then hit Ctrl+P, type task, then a space and then "Clear build Directory and Run CMake". Press enter to execute the task.
Next, hit Ctrl+Shift+B, select "Build & Run" using the arrow keys, and hit enter to build and run the application.

There are other tasks for running "make clean" and for building without running the application as well.

VSCode will probably give you a warning that Python.h was not found in the include path. You can just click the yellow light bulb, and select Add to "includePath": /usr/include/python3.x.