main.cpp

#include <vector>
#include <pybind11/pybind11.h>
#include <pybind11/stl.h>
#include <pybind11/numpy.h>
#include <chrono>
#include <thread>
#include <iostream>

namespace py = pybind11;

float some_fn(float arg1, float arg2)
{
    return arg1 + arg2;
}

class SomeClass
{
    float multiplier;

public:
    SomeClass(float multiplier_) : multiplier(multiplier_){};

    float multiply(float input)
    {
        return multiplier * input;
    }

    std::vector<float> multiply_list(std::vector<float> items)
    {
        for (auto i = 0; i < items.size(); i++)
        {
            items[i] = multiply(items.at(i));
        }
        return items;
    }

    // py::tuple multiply_two(float one, float two) {
    //   return py::make_tuple(multiply(one), multiply(two));
    // }

    std::vector<std::vector<uint8_t>> make_image()
    {
        auto out = std::vector<std::vector<uint8_t>>();
        for (auto i = 0; i < 128; i++)
        {
            out.push_back(std::vector<uint8_t>(64));
        }
        for (auto i = 0; i < 30; i++)
        {
            for (auto j = 0; j < 30; j++)
            {
                out[i][j] = 255;
            }
        }
        return out;
    }

    void set_mult(float val)
    {
        multiplier = val;
    }

    float get_mult()
    {
        return multiplier;
    }

    void function_that_takes_a_while()
    {
        py::gil_scoped_release release;
        std::cout << "starting" << std::endl;
        std::this_thread::sleep_for(std::chrono::milliseconds(2000));
        std::cout << "ended" << std::endl;

        // py::gil_scoped_acquire acquire;
        // auto list = py::list();
        // list.append(1);
    }
};

SomeClass some_class_factory(float multiplier)
{
    return SomeClass(multiplier);
}

PYBIND11_MODULE(module_name, module_handle)
{
    module_handle.doc() = "I'm a docstring";
    module_handle.def("some_fn_python_name", &some_fn);
    module_handle.def("some_class_factory", &some_class_factory);
    py::class_<SomeClass>(
        module_handle, "PySomeClass")
        .def(py::init<float>())
        .def_property("multiplier", &SomeClass::get_mult, &SomeClass::set_mult)
        .def("multiply", &SomeClass::multiply)
        .def("multiply_list", &SomeClass::multiply_list)
        // .def_property_readonly("image", &SomeClass::make_image)
        .def_property_readonly("image", [](SomeClass &self)
                               {
				      py::array out = py::cast(self.make_image());
				      return out; })
        // .def("multiply_two", &SomeClass::multiply_two)
        .def("multiply_two", [](SomeClass &self, float one, float two)
             { return py::make_tuple(self.multiply(one), self.multiply(two)); })
        .def("function_that_takes_a_while", &SomeClass::function_that_takes_a_while);
}