opencv中ptr的使用

#include <QCoreApplication>

#include<stdio.h>

#include<opencv2/highgui/highgui.hpp>

#include<opencv2/core/core.hpp>

using namespace cv;

void colorReduce(Mat &image,int div =64){

    int nl = image.rows;

    int nc =image.cols*image.channels();

    for(int j =0;j<nl;j++ )

    {

      uchar* data = image.ptr<uchar>(j);//最需要注意的就是这行代码的使用

        for(int i=0;i<nc;i++)

        {
             qDebug("the first data[i] is %d",data[i]);

             data[i] = data[i]/div*div ;
            /**************************
            
 另外此处还可以如此 使用uchar *data = image.ptr<uchar>(j)[i];
 这种方式更加经典，执行效率更高

 ********************************/
             qDebug("the second data[i] is %d",data[i]);

// data[i] = data[i]/(div*div)+ div/2;

// data[i] = data[i]%div+ div/2;

         //   data[i] = data[i] + div/2;

        }

    }





}

int main()

{

    Mat image1;

    image1 = imread("/home/bi/pic/mei.jpg");

    namedWindow("image1");

    imshow("image1",image1);

   namedWindow("colorReduce");

   colorReduce(image1);

    //QCoreApplication a(argc, argv);

   imshow("colorReduce",image1);

   waitKey();

   return 0;

    //return a.exec();

}

 1 template<typename _Tp> class Ptr

 2 {

 3 public:

 4 // default constructor

 5 Ptr();

 6 // constructor that wraps the object pointer

 7 Ptr(_Tp* _obj);

 8 // destructor: calls release()

 9 ~Ptr();

10 // copy constructor; increments ptr’s reference counter

11 Ptr(const Ptr& ptr);

12 // assignment operator; decrements own reference counter

13 // (with release()) and increments ptr’s reference counter

14 Ptr& operator = (const Ptr& ptr);

15 // increments reference counter                                             

16 void addref();