OpenCv c++ 为基本打印垫功能创建一个 C 包装器？

Posted 2023-02-22

【中文标题】OpenCv c++ 为基本打印垫功能创建一个 C 包装器？

【英文标题】：OpenCv c++ Create a C wrapper for basic print mat function?

【发布时间】：2013-11-17 23:11:23

【问题描述】：

我可以像这样创建和打印矩阵：

  Mat M(2,2, CV_8UC3, Scalar(0,0,255));
 cout << "M = " << endl << " " << M << endl << endl;

我的 C++ 函数的 C 包装是这样的：

Mat* cv_printmat(Mat* mat) 

   return  cout << "Matrix = " << endl << " " << *mat << endl << endl;
    

不确定从这里去哪里...我需要按原样声明“Mat* mat”...一个不透明的指针 出于我的目的...但收到此错误

       In file included from /usr/include/c++/4.8/ios:44:0,
             from /usr/include/c++/4.8/istream:38,
             from /usr/include/c++/4.8/sstream:38,
             from /usr/include/c++/4.8/complex:45,
             from /usr/local/include/opencv2/core/cvstd.inl.hpp:48,
             from /usr/local/include/opencv2/core.hpp:1256,
             from /usr/local/include/opencv2/opencv.hpp:46,
             from opencv_generated.hpp:1,
             from cl-opencv-glue.cpp:1:
/usr/include/c++/4.8/bits/basic_ios.h:115:7: note: 
candidate is: std::basic_ios<_CharT, _Traits>::operator 
void*() const [with _CharT = char; _Traits = std::
char_traits<char>] <near match>
   operator void*() const
   ^
/usr/include/c++/4.8/bits/basic_ios.h:115:7: note:   
no known conversion for implicit ‘this’ parameter from ‘void*’ to ‘cv::Mat*’

用这个编译：

 g++ -Wall -shared -fPIC -o libcl-opencv-glue.so cl-opencv-glue.cpp

任何帮助都非常感谢=)。

编辑...新错误

 opencv-glue.cpp :150:58 error:invalid user-defined conversion from                 
‘std::basic_ostream<char>::__ostream_type aka std
::basic_ostream<char>’ to ‘cv::Mat*’ [-fpermissive]
     return cout << "M = " << endl << " " << *mat << endl << endl;
                                                          ^
      In file included from /usr/include/c++/4.8/ios:44:0,
                 from /usr/include/c++/4.8/istream:38,
                 from /usr/include/c++/4.8/sstream:38,
                 from /usr/include/c++/4.8/complex:45,
                 from /usr/local/include/opencv2/core/cvstd.inl.hpp:48,
                 from /usr/local/include/opencv2/core.hpp:1256,
                 from /usr/local/include/opencv2/opencv.hpp:46,
                 from opencv_generated.hpp:1,
                 from opencv-glue.cpp:1:
/usr/include/c++/4.8/bits/basic_ios.h:115:7: note: candidate is: 
std::basic_ios<_CharT, _Traits>::operator void*() const [with _
CharT = char; _Traits = std::char_traits<char>] <near match>
       operator void*() const
       ^
/usr/include/c++/4.8/bits/basic_ios.h:115:7: note:   
no known conversion for implicit ‘this’ parameter from 
‘void*’ to ‘cv::Mat*’

【问题讨论】：

只是备注：只要您使用 Mat，这不是 C 包装器。

【参考方案1】：

您的返回数据类型是 cv::Mat*，而 std::cout 的返回数据类型是 void*。不确定您的目标是什么，但如果您只是想打印，这应该可以编译。

void cv_printmat(Mat* mat) 
  cout << "Matrix = " << endl << " " << *mat << endl << endl;


int main(int argc, char* argv[])
   cv::Mat M(2,2, CV_8UC3, cv::Scalar(0,0,255));
   cv_printmat(&M);

【讨论】：

感谢您的回复....但返回无效时仍然出现错误...关于此错误的任何建议是偶然的