HOW TO USE C++ code from python using pybind11

Prepare the environment

Clone and prepare folder

$ git clone https://github.com/dvisionlab/pybind_examples
$ cd pybind_examples

Prepare a virtual environment where to install pybind11

$ python3 -m venv venv
$ . ./venv/bin/activate

Get pybind11 from github, clone it into pybind_test directory and install it

(venv) $ git clone https://github.com/pybind/pybind11
(venv) $ cd pybind11
(venv) $ python setup.py install

Standard example (src folder)

Create a build folder, cd into it and run

(venv) $ ccmake ../src

A TUI should pop up, press c to configure, then

• set USE_PYTHON_INCLUDE_DIR ON
• set CMAKE_BUILD_TYPE Release

Press c and g to generate the makefile, then

(venv) $ make

The module foo should be now present:

(venv) $ python
>>> import foo
>>> foo.add(1, 5)
6

Advanced example (src_vmtk folder)

Pre-requisite: install vmtk

$ git clone https://github.com/vmtk/vmtk
$ mkdir vmtk-build
$ cd vmtk-build
$ ccmake ../vmtk

Then do the following (toggle t for advanced mode):

• set BUILD_SHARED_LIBS OFF
• set VTK_VMTK_WRAP_PYTHON OFF
• set CMAKE_BUILD_TYPE Release
• set CMAKE_CXX_FLAGS -std=gnu++11 -fpic

Then configure with c and generate by pressing g and build:

$ make -j2

Compiling the example

(venv) $ cd pybind_examples
(venv) $ mkdir build_vmtk
(venv) $ cd build_vmtk
$ ccmake ../src_vmtk

Configure using the following:

• set USE_PYTHON_INCLUDE_DIR ON
• set CMAKE_BUILD_TYPE Release
• set ITK_DIRECTORY as path_to_vmtk_build/ITK-Build
• set VTK_DIRECTORY as path_to_vmtk_build/VTK-Build
• set VMTK_DIRECTORY as path_to_vmtk_build/Install

Configure and generate using "c" and "g"

(venv) $ make
(venv) $ python3
>>> import vmtk