Xonxt/main.cpp

## main.cpp
/*
This requires adding the "include" directory of your Python installation to the include diretories
of your project, e.g., in Visual Studio you'd add `C:\Program Files\Python36\include`.
You also need to add the 'include' directory of your NumPy package, e.g.
`C:\Program Files\PythonXX\Lib\site-packages\numpy\core\include`.

Additionally, you need to link your "python3#.lib" library, e.g. `C:\Program Files\Python3X\libs\python3X.lib`.
*/

// python bindings
#include "Python.h"
#include "numpy/arrayobject.h"

#include <iostream>

#include "opencv2/opencv.hpp"

// references to all the functions
PyObject *m_PyDict, *m_PyFooBar;

// reference to the Pyhton module
PyObject* m_PyModule;

int main(int argc, char** argv) {
  // initialize Python embedding
  Py_Initialize();

  // set the command line arguments (can be crucial for some python-packages, like tensorflow)
  PySys_SetArgv(argc, (wchar_t**) argv);

  // add the current folder to the Python's PATH
  PyObject *sys_path = PySys_GetObject("path");
  PyList_Append(sys_path, PyUnicode_FromString("."));

  // this macro is defined by NumPy and must be included
  import_array1(-1);

  // load our python script (see the gist at the bottom)
  // use the script's filename, sans the extension
  m_PyModule = PyImport_ImportModule("pythonScript");

  if (m_PyModule != NULL)
  {
    // get dictionary of all available entities in the module
    m_PyDict = PyModule_GetDict(m_PyModule);

    // grab the functions we are interested in (using its name)
    m_PyFooBar = PyDict_GetItemString(m_PyDict, "foo_bar");

    // execute the function
    if (m_PyFooBar != NULL)
    {
      // take a cv::Mat object from somewhere (we'll just create an empty one)
      cv::Mat img = cv::Mat::zeros(480, 640, CV_8U);

      // total number of elements (here it's a greyscale 640x480)
      const unsigned int nElem = 640 * 480;

      // create an array of apropriate datatype
      uchar* m = new uchar[nElem];

      // copy the data from the cv::Mat object into the array
      std::memcpy(m, img.data, nElem * sizeof(uchar));

      // the dimensions of the matrix
      npy_intp mdim[] = { 480, 640 };

      // convert the cv::Mat to numpy.array
      PyObject* mat = PyArray_SimpleNewFromData(2, mdim, NPY_UINT8, (void*) m);

      // create a Python-tuple of arguments for the function call
      // "()" means "tuple". "O" means "object"
      PyObject* args = Py_BuildValue("(O)", mat);
      // if we want several arguments, we can write ("i" means "integer"):
      // PyObject* args = Py_BuildValue("(OOi)", mat, mat, 123);
      // to send two images and an integer, equivalent to Python's (mat, mat, 123) tuple
      // see detailed explanation here: https://docs.python.org/2.0/ext/buildValue.html

      // execute the function
      PyObject* result = PyEval_CallObject(m_PyFooBar, args);

      // process the result
      // ...

      // decrement the object references
      Py_XDECREF(mat);
      Py_XDECREF(result);
      Py_XDECREF(args);

      delete[] m;
    }
  }
  else
  {
    std::cerr << "Failed to load the Python module!" << std::endl;
    PyErr_Print();
  }

  return 0;
}

## main2.cpp
// same example, but for a 3-channel RGB image.

// python bindings
#include "Python.h"
#include "numpy/arrayobject.h"

#include <iostream>

#include "opencv2/opencv.hpp"

// for the references to all the functions
PyObject *m_PyDict, *m_PyFooBar;

// for the reference to the Pyhton module
PyObject* m_PyModule;

int main(int argc, char** argv) {
  // initialize everything (see gist above for details)
  Py_Initialize();
  PySys_SetArgv(argc, (wchar_t**)argv);
  PyObject *sys_path = PySys_GetObject("path");
  PyList_Append(sys_path, PyUnicode_FromString("."));
  import_array1(-1);
  m_PyModule = PyImport_ImportModule("pythonScript");

  if (m_PyModule != NULL)
  {
    // get dictionary of available items in the module
    m_PyDict = PyModule_GetDict(m_PyModule);

    // grab the functions we are interested in
    m_PyFooBar = PyDict_GetItemString(m_PyDict, "foo_bar");

    // execute the function
    if (m_PyFooBar != NULL)
    {
      // take a cv::Mat object from somewhere (we'll just create one)
      cv::Mat img = cv::Mat::zeros(480, 640, CV_8UC3);

      // total number of elements (here it's an RGB image of size 640x480)
      const unsigned int nElem = 640 * 480 * 3;

      // create an array of apropriate datatype
      uchar* m = new uchar[nElem];

      // copy the data from the cv::Mat object into the array
      std::memcpy(m, img.data, nElem * sizeof(uchar));

      // the dimensions of the matrix
      npy_intp mdim[] = { 480, 640, 3 };

      // convert the cv::Mat to numpy.array
      PyObject* mat = PyArray_SimpleNewFromData(3, mdim, NPY_UINT8, (void*) m);

      // create a Python-tuple of arguments for the function call
      // "()" means "tuple". "O" means "object"
      PyObject* args = Py_BuildValue("(O)", mat);

      // execute the function
      PyObject* result = PyEval_CallObject(m_PyFooBar, args);

      // process the result
      // ...

      // decrement the object references
      Py_XDECREF(mat);
      Py_XDECREF(result);
      Py_XDECREF(args);

      delete[] m;
    }
  }
  else
  {
    std::cerr << "Failed to load the Python module!" << std::endl;
    PyErr_Print();
  }

  return 0;
}

## pythonScript.py
import cv2
import numpy as np

# define the function that we will call from the C++ code
def foo_bar(img=None):
    if img is not None:
       cv2.imshow("image in python", img)
	/*
	This requires adding the "include" directory of your Python installation to the include diretories
	of your project, e.g., in Visual Studio you'd add `C:\Program Files\Python36\include`.
	You also need to add the 'include' directory of your NumPy package, e.g.
	`C:\Program Files\PythonXX\Lib\site-packages\numpy\core\include`.

	Additionally, you need to link your "python3#.lib" library, e.g. `C:\Program Files\Python3X\libs\python3X.lib`.
	*/

	// python bindings
	#include "Python.h"
	#include "numpy/arrayobject.h"

	#include <iostream>

	#include "opencv2/opencv.hpp"

	// references to all the functions
	PyObject m_PyDict, m_PyFooBar;

	// reference to the Pyhton module
	PyObject* m_PyModule;

	int main(int argc, char** argv) {
	// initialize Python embedding
	Py_Initialize();

	// set the command line arguments (can be crucial for some python-packages, like tensorflow)
	PySys_SetArgv(argc, (wchar_t**) argv);

	// add the current folder to the Python's PATH
	PyObject *sys_path = PySys_GetObject("path");
	PyList_Append(sys_path, PyUnicode_FromString("."));

	// this macro is defined by NumPy and must be included
	import_array1(-1);

	// load our python script (see the gist at the bottom)
	// use the script's filename, sans the extension
	m_PyModule = PyImport_ImportModule("pythonScript");

	if (m_PyModule != NULL)
	{
	// get dictionary of all available entities in the module
	m_PyDict = PyModule_GetDict(m_PyModule);

	// grab the functions we are interested in (using its name)
	m_PyFooBar = PyDict_GetItemString(m_PyDict, "foo_bar");

	// execute the function
	if (m_PyFooBar != NULL)
	{
	// take a cv::Mat object from somewhere (we'll just create an empty one)
	cv::Mat img = cv::Mat::zeros(480, 640, CV_8U);

	// total number of elements (here it's a greyscale 640x480)
	const unsigned int nElem = 640 * 480;

	// create an array of apropriate datatype
	uchar* m = new uchar[nElem];

	// copy the data from the cv::Mat object into the array
	std::memcpy(m, img.data, nElem * sizeof(uchar));

	// the dimensions of the matrix
	npy_intp mdim[] = { 480, 640 };

	// convert the cv::Mat to numpy.array
	PyObject* mat = PyArray_SimpleNewFromData(2, mdim, NPY_UINT8, (void*) m);

	// create a Python-tuple of arguments for the function call
	// "()" means "tuple". "O" means "object"
	PyObject* args = Py_BuildValue("(O)", mat);
	// if we want several arguments, we can write ("i" means "integer"):
	// PyObject* args = Py_BuildValue("(OOi)", mat, mat, 123);
	// to send two images and an integer, equivalent to Python's (mat, mat, 123) tuple
	// see detailed explanation here: https://docs.python.org/2.0/ext/buildValue.html

	// execute the function
	PyObject* result = PyEval_CallObject(m_PyFooBar, args);

	// process the result
	// ...

	// decrement the object references
	Py_XDECREF(mat);
	Py_XDECREF(result);
	Py_XDECREF(args);

	delete[] m;
	}
	}
	else
	{
	std::cerr << "Failed to load the Python module!" << std::endl;
	PyErr_Print();
	}

	return 0;
	}
	// same example, but for a 3-channel RGB image.

	// python bindings
	#include "Python.h"
	#include "numpy/arrayobject.h"

	#include <iostream>

	#include "opencv2/opencv.hpp"

	// for the references to all the functions
	PyObject m_PyDict, m_PyFooBar;

	// for the reference to the Pyhton module
	PyObject* m_PyModule;

	int main(int argc, char** argv) {
	// initialize everything (see gist above for details)
	Py_Initialize();
	PySys_SetArgv(argc, (wchar_t**)argv);
	PyObject *sys_path = PySys_GetObject("path");
	PyList_Append(sys_path, PyUnicode_FromString("."));
	import_array1(-1);
	m_PyModule = PyImport_ImportModule("pythonScript");

	if (m_PyModule != NULL)
	{
	// get dictionary of available items in the module
	m_PyDict = PyModule_GetDict(m_PyModule);

	// grab the functions we are interested in
	m_PyFooBar = PyDict_GetItemString(m_PyDict, "foo_bar");

	// execute the function
	if (m_PyFooBar != NULL)
	{
	// take a cv::Mat object from somewhere (we'll just create one)
	cv::Mat img = cv::Mat::zeros(480, 640, CV_8UC3);

	// total number of elements (here it's an RGB image of size 640x480)
	const unsigned int nElem = 640 * 480 * 3;

	// create an array of apropriate datatype
	uchar* m = new uchar[nElem];

	// copy the data from the cv::Mat object into the array
	std::memcpy(m, img.data, nElem * sizeof(uchar));

	// the dimensions of the matrix
	npy_intp mdim[] = { 480, 640, 3 };

	// convert the cv::Mat to numpy.array
	PyObject* mat = PyArray_SimpleNewFromData(3, mdim, NPY_UINT8, (void*) m);

	// create a Python-tuple of arguments for the function call
	// "()" means "tuple". "O" means "object"
	PyObject* args = Py_BuildValue("(O)", mat);

	// execute the function
	PyObject* result = PyEval_CallObject(m_PyFooBar, args);

	// process the result
	// ...

	// decrement the object references
	Py_XDECREF(mat);
	Py_XDECREF(result);
	Py_XDECREF(args);

	delete[] m;
	}
	}
	else
	{
	std::cerr << "Failed to load the Python module!" << std::endl;
	PyErr_Print();
	}

	return 0;
	}
	import cv2
	import numpy as np

	# define the function that we will call from the C++ code
	def foo_bar(img=None):
	if img is not None:
	cv2.imshow("image in python", img)