macOS(Intel)配置opencv(C++)

只是做一份归档。如有不当之处请大佬们指正，谢谢！

前置条件：homebrew,Xcode

1. 安装pkg-config

   brew install pkg-config
   

2. 安装opencv

   brew install opencv

   测试是否安装完成：pkg-config --cflags --libs opencv

       2.1 此时您可能会出现下面的错误：

       Package opencv was not found in the pkg-config search path.
       Perhaps you should add the directory containing `opencv.pc'
       to the PKG_CONFIG_PATH environment variable
       No package 'opencv' found

       你先别急：原因是缺失了opencv.pc这个配置信息文件，故解决方法就是添加这个文件然后将其导入到环境变量中。

           2.1.1解决方案：先创建opencv.pc文件，这里要注意它的路径信息：

           cd /usr/local/lib
           sudo mkdir pkgconfig
           cd pkgconfig
           sudo touch opencv.pc
   
           然后在opencv.pc中添加以下信息，注意这些信息需要与自己安装opencv时的库路径对应：

           prefix=/usr/local
           exec_prefix=${prefix}
           includedir=${prefix}/include
           libdir=${exec_prefix}/lib
   
           Name: opencv
           Description: The opencv library
           Version:4.8.0
           Cflags: -I${includedir}/openCV4
           Libs: -L${libdir} -lopencv_shape -lopencv_stitching -lopencv_objdetect -lopencv_superres -lopencv_videostab -lopencv_calib3d -lopencv_features2d -lopencv_highgui -lopencv_videoio -lopencv_imgcodecs -lopencv_video -lopencv_photo -lopencv_ml -lopencv_imgproc -lopencv_flann  -lopencv_core
    ~                                               
           保存退出，然后将文件导入到环境变量：

           export  PKG_CONFIG_PATH=/usr/local/lib/pkgconfig

           之后执行pkg-config --cflags --libs opencv检验

由于是用C++并且笔者想在终端中直接使用，所以需要ln -s /usr/local/include/openCV4/openCV2 openCV2

默认情况下，通过brew安装的opencv目录于：/usr/local/Cellar/opencv

如果想在终端下使用，所以需要建立软连接

注意："OpenCV 4.x+ requires enabled C++11 support"


3. 下面给出测试

   测试来自opencv官方例程的代码文件

   #include "openCV2/core.hpp"
   #include "openCV2/imgproc.hpp"
   #include "openCV2/highgui.hpp"
   #include "openCV2/videoio.hpp"
   #include <iostream>
   
   using namespace cv;
   using namespace std;
   
   void drawText(Mat & image);
   
   int main()
   {
       cout << "Built with OpenCV " << CV_VERSION << endl;
       Mat image;
       VideoCapture capture;
       capture.open(0);
       if(capture.isOpened())
       {
           cout << "Capture is opened" << endl;
           for(;;)
           {
               capture >> image;
               if(image.empty())
                   break;
               drawText(image);
               imshow("Sample", image);
               if(waitKey(10) >= 0)
                   break;
           }
       }
       else
       {
           cout << "No capture" << endl;
           image = Mat::zeros(480, 640, CV_8UC1);
           drawText(image);
           imshow("Sample", image);
           waitKey(0);
       }
       return 0;
   }
   
   void drawText(Mat & image)
   {
       putText(image, "Hello OpenCV",
               Point(20, 50),
               FONT_HERSHEY_COMPLEX, 1, // font face and scale
               Scalar(255, 255, 255), // white
               1, LINE_AA); // line thickness and type
   }
   
   

4. g++ example.cpp -o example.o -c -Wall -I/usr/local/include/openCV4 -std=c++11
   

5. g++ example.o -o opencv_example -L/usr/local/lib -lopencv_shape -lopencv_stitching -lopencv_objdetect -lopencv_superres -lopencv_videostab -lopencv_calib3d -lopencv_features2d -lopencv_highgui -lopencv_videoio -lopencv_imgcodecs -lopencv_video -lopencv_photo -lopencv_ml -lopencv_imgproc -lopencv_flann -lopencv_core