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目的

• C++代码提供python接口。
• 用CMakeLists.txt和setup.py搭配，编译。

先安装pybind11

git clone https://github.com/pybind/pybind11.git
cd pybind11
mkdir build
cd build
cmake ..
make
sudo make install

example.cpp

#include <pybind11/pybind11.h>
#include <opencv2/opencv.hpp>

#define STRINGIFY(x) #x
#define MACRO_STRINGIFY(x) STRINGIFY(x)

int add(int i, int j) {
    return i + j;
}

void show() {
    printf("in show()");
    cv::Mat src = cv::imread("/home/xxx/1.png");
    cv::imshow("src", src);
    cv::waitKey();
}
namespace py = pybind11;

PYBIND11_MODULE(xpose, m) {
    m.doc() = R"pbdoc(
        Pybind11 example plugin
        -----------------------

        .. currentmodule:: cmake_example

        .. autosummary::
           :toctree: _generate

           add
           subtract
    )pbdoc";

    m.def("show", &show, R"pbdoc(
        Add two numbers

        Some other explanation about the add function.
    )pbdoc");

    m.def("add", &add, R"pbdoc(
        Add two numbers

        Some other explanation about the add function.
    )pbdoc");

    m.def("subtract", [](int i, int j) { return i - j; }, R"pbdoc(
        Subtract two numbers

        Some other explanation about the subtract function.
    )pbdoc");

#ifdef VERSION_INFO
    m.attr("__version__") = MACRO_STRINGIFY(VERSION_INFO);
#else
    m.attr("__version__") = "dev";
#endif
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.4...3.18)
project(xpose)

find_package(pybind11 CONFIG)
find_package(OpenCV REQUIRED)

include_directories(include
            ${OpenCV_INCLUDE_DIRS}
            ${pybind11_INCLUDE_DIRS}
            )

# add_subdirectory(pybind11)
pybind11_add_module(xpose example.cpp)

# EXAMPLE_VERSION_INFO is defined by setup.py and passed into the C++ code as a
# define (VERSION_INFO) here.

target_link_libraries(xpose PRIVATE pybind11::module  ${OpenCV_LIBRARIES} ${pybind11_LIBRARIES})

# target_compile_definitions(cmake_example
#                            PRIVATE VERSION_INFO=${EXAMPLE_VERSION_INFO})


# target_link_libraries(cmake_example PRIVATE
#     ${OpenCV_LIBRARIES}
#     )

可以先用cmake验证能否编译过

mkdir build
cmake ..
make

setup.py

import os
import re
import subprocess
import sys

from setuptools import Extension, setup
from setuptools.command.build_ext import build_ext

# Convert distutils Windows platform specifiers to CMake -A arguments
PLAT_TO_CMAKE = {
    "win32": "Win32",
    "win-amd64": "x64",
    "win-arm32": "ARM",
    "win-arm64": "ARM64",
}


# A CMakeExtension needs a sourcedir instead of a file list.
# The name must be the _single_ output extension from the CMake build.
# If you need multiple extensions, see scikit-build.
class CMakeExtension(Extension):
    def __init__(self, name, sourcedir=""):
        Extension.__init__(self, name, sources=[])
        self.sourcedir = os.path.abspath(sourcedir)


class CMakeBuild(build_ext):
    def build_extension(self, ext):
        extdir = os.path.abspath(os.path.dirname(self.get_ext_fullpath(ext.name)))

        print("extdir =========================================================== ", extdir)

        # required for auto-detection & inclusion of auxiliary "native" libs
        if not extdir.endswith(os.path.sep):
            extdir += os.path.sep

        debug = int(os.environ.get("DEBUG", 0)) if self.debug is None else self.debug
        cfg = "Debug" if debug else "Release"

        # CMake lets you override the generator - we need to check this.
        # Can be set with Conda-Build, for example.
        cmake_generator = os.environ.get("CMAKE_GENERATOR", "")

        # Set Python_EXECUTABLE instead if you use PYBIND11_FINDPYTHON
        # EXAMPLE_VERSION_INFO shows you how to pass a value into the C++ code
        # from Python.
        cmake_args = [
            f"-DCMAKE_LIBRARY_OUTPUT_DIRECTORY={extdir}",
            f"-DPYTHON_EXECUTABLE={sys.executable}",
            f"-DCMAKE_BUILD_TYPE={cfg}",  # not used on MSVC, but no harm
        ]
        build_args = []
        # Adding CMake arguments set as environment variable
        # (needed e.g. to build for ARM OSx on conda-forge)
        if "CMAKE_ARGS" in os.environ:
            cmake_args += [item for item in os.environ["CMAKE_ARGS"].split(" ") if item]

        # In this example, we pass in the version to C++. You might not need to.
        cmake_args += [f"-DEXAMPLE_VERSION_INFO={self.distribution.get_version()}"]

        # Set CMAKE_BUILD_PARALLEL_LEVEL to control the parallel build level
        # across all generators.
        if "CMAKE_BUILD_PARALLEL_LEVEL" not in os.environ:
            # self.parallel is a Python 3 only way to set parallel jobs by hand
            # using -j in the build_ext call, not supported by pip or PyPA-build.
            if hasattr(self, "parallel") and self.parallel:
                # CMake 3.12+ only.
                build_args += [f"-j{self.parallel}"]

        if not os.path.exists(self.build_temp):
            os.makedirs(self.build_temp)

        print("======================")
        print("ext.sourcedir = ", ext.sourcedir)
        print("cmake_args = ", cmake_args)
        print("self.build_temp = ", self.build_temp)
        print("build_args = ", build_args)

        subprocess.check_call(
            ["cmake", ext.sourcedir] + cmake_args, cwd=self.build_temp
        )
        subprocess.check_call(
            ["cmake", "--build", "."] + build_args, cwd=self.build_temp
        )
# The information here can also be placed in setup.cfg - better separation of
# logic and declaration, and simpler if you include description/version in a file.
setup(
    name="xpose",
    version="0.0.1",
    author="Dean Moldovan",
    author_email="dean0x7d@gmail.com",
    description="A test project using pybind11 and CMake",
    long_description="",
    ext_modules=[CMakeExtension("xpose")],
    cmdclass={"build_ext": CMakeBuild},
    zip_safe=False,
    extras_require={"test": ["pytest>=6.0"]},
    python_requires=">=3.6",
)

编译出wheel文件
python setup.py sdist_wheel

安装pip install dist/xpose-0.0.1-cp38-cp38-linux_x86_64.whl

测试

python
import xpose
xpose.show()

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