Pybind11 用于 C++ 代码，内部结构通过静态工厂方法创建

Question

我有自己的 C++，我正在尝试使用 Pybind11 生成 python 绑定：

auto markerParams = MarkerDetector::Params::create(MarkerType::chessboard);
markerDetector.detect(image, markerParams);

我在为 MarkerDetector::Params 结构生成绑定时遇到问题，因为它是使用以枚举作为参数的工厂方法构造的内部结构：

enum MarkerType { chessboard, tag };

typedef std::vector<cv::Point> ContourType;
typedef std::vector<cv::Point2d> ContourTyped;

//              contour full, contour approximate, area, corners
typedef std::tuple<ContourType, ContourType, double, ContourTyped> MarkerDescriptor;


class MarkerDetector {
    public:
        std::vector<MarkerDescriptor> detect(Mat image, const Params params);

        struct Params {
            int rows, cols;
            ColorRange borderColor;
            ShapeDetector::Params borderShape;
            cv::Size borderSize;
            cv::Size Size;


            static Params create(MarkerType markerType) {
                static Params markerTypes[] = {
                    { 3, 6, ColorRange::GREEN, ShapeDetector::Params::RECTANGLE, cv::Size(30,30), cv::Size(140, 140) }
                };
                return markerTypes[markerType];
            }
        };
    };

有人知道如何处理这种更高级的情况吗？

Answer 1

我已经根据您的设计使用内部结构对您的代码进行了基本实现运行。为简洁起见，我只包含了 MarkerDetector 和 Params 的相关详细信息，但它应该与您所做的相匹配。

C++代码：

#include <pybind11/pybind11.h>

namespace py = pybind11;

enum MarkerType { chessboard, tag };


class MarkerDetector {
    public:
    MarkerDetector() { }
    struct Params {
        int rows;
        int cols;
        static Params create(MarkerType markerType) {
            static Params markerTypes[] = {
                    { 1, 2 },
                    { 3, 4 }
            };
            return markerTypes[markerType];
        }
    };

};


PYBIND11_MODULE(example, m) {
    m.doc() = "pybind11 example"; // optional module docstring

    py::enum_<MarkerType>(m, "MarkerType")
         .value("chessboard", MarkerType::chessboard)
         .value("tag",        MarkerType::tag)
         .export_values();

    py::class_<MarkerDetector>(m, "MarkerDetector")
            .def(py::init<>())
            ;

    py::class_<MarkerDetector::Params>(m, "MarkerDetectorParams")
            .def(py::init<>())
            .def_readwrite("rows", &MarkerDetector::Params::rows)
            .def_readwrite("cols", &MarkerDetector::Params::cols)
            .def("create", (MarkerDetector::Params (*)(MarkerType)) &MarkerDetector::Params::create)
            ;
}

(有兴趣的可以命令行编译上面的:)

c++ -O3 -Wall -shared -std=c++11 -fPIC `python3 -m pybind11 --includes` example.cpp -o example`python3-config --extension-suffix` -L /usr/local/Cellar/python3/3.6.4/Frameworks/Python.framework/Versions/3.6/lib/ -lpython3.6

python代码：

import sys
sys.path.append('/Volumes/Programs/workspaces/workspace 1/Project CPP 2')

import example

mtype = example.MarkerType.chessboard
print (mtype)

x = example.MarkerDetectorParams.create(example.MarkerType.chessboard)
print (x)
print (x.rows)
print (x.cols)

y = example.MarkerDetectorParams.create(example.MarkerType.tag)
print (y)
print (y.rows)
print (y.cols)

这给出了以下输出，按照设计看起来是正确的：

MarkerType.chessboard
<example.MarkerDetectorParams object at 0x1043e35a8>
1
2
<example.MarkerDetectorParams object at 0x1043e3768>
3
4

我希望这能给您一些帮助。此致，AS

Pybind11 用于 C++ 代码，内部结构通过静态工厂方法创建

Pybind11 for C++ code with inner struct created via static factory method

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