#include <iostream>
#include <opencv2/core.hpp>
#include <opencv2/imgcodecs.hpp>
using namespace std;
using namespace cv;

int main()
{
    Mat a = (Mat_<double>(2, 3) << 1, 2, 3, 4, 5, 6);
    cout << "a ref count = " << a.u->refcount << endl; // 1

    Mat b = a;  // b只构建Mat头部, 与a共享数据, 引用计数加1, 引用计数结果为2
    cout << "a ref count = " << a.u->refcount << endl; // 2
    cout << "b ref count = " << b.u->refcount << endl; // 2
    cout << endl;

    Mat c = b;  // c只构建Mat头部, 与a共享数据, 引用计数加1, 引用计数结果为3
    cout << "a ref count = " << a.u->refcount << endl; // 3
    cout << "b ref count = " << b.u->refcount << endl; // 3
    cout << "c ref count = " << c.u->refcount << endl; // 3
    cout << endl;

    c = b.clone();  // c从b克隆一份数据, 不再与a, b共享数据, 引用计数减1, 引用计数结果为2
    cout << "a ref count = " << a.u->refcount << endl; // 2
    cout << "b ref count = " << b.u->refcount << endl; // 2
    cout << "c ref count = " << c.u->refcount << endl; // 1
    cout << endl;

    Mat d;
    c.copyTo(d);        // c将数据拷贝到d 
    cout << "a ref count = " << a.u->refcount << endl; // 2
    cout << "b ref count = " << b.u->refcount << endl; // 2
    cout << "c ref count = " << c.u->refcount << endl; // 1
    cout << "d ref count = " << d.u->refcount << endl; // 1
    cout << endl;

    return 0;
}