C++ 如何使cv:：setMouseCallback函数工作

我看到一些问题可能是相同的。阅读答案后，我仍然无法使我的代码正常工作。因此，如果我重复这些帖子，我很抱歉

我成功地编写了以下代码：

        #include <opencv2/core/core.hpp>
        #include <opencv2/highgui/highgui.hpp>
        #include <opencv2/imgproc/imgproc.hpp>

        #include <iostream>
        #include <string>

        bool leftButtonDown = false, leftButtonUp = false;
        cv::Mat img;
        cv::Point cor1, cor2;
        cv::Rect rect;

    void mouseCall(int event, int x, int y, int, void*) {
        if (event == cv::EVENT_LBUTTONDOWN)                                                                     //finding first corner
        {
            leftButtonDown = true; cor1.x = x; cor1.y = y; std::cout << "Corner 1: " << cor1 << std::endl;
        }
        if (event == cv::EVENT_LBUTTONUP) {
            if (abs(x - cor1.x)>20 && abs(y - cor1.y)>5)                                                        //finding second corner and checking whether the region is too small 
            {
                leftButtonUp = true; cor2.x = x; cor2.y = y; std::cout << "Corner 2: " << cor2 << std::endl;
            }
            else { std::cout << "Select more than 5 pixels" << std::endl; }
        }

        if (leftButtonDown == true && leftButtonUp == false)                                                    //when the left button is clicked and let off 
        {                                                                                                       //draw a rectangle continuously
            cv::Point pt; pt.x = x; pt.y = y;
            cv::Mat temp_img = img.clone();
            rectangle(temp_img, cor1, pt, cv::Scalar(0, 0, 255));                                            
            cv::imshow("Original", temp_img);
        }
        else if (event == cv::EVENT_MOUSEMOVE)                                                                  //tracking mouse movement
        {
            std::cout << "Mouse moving over the window - position (" << x << ", " << y << ")" << std::endl;

        }
        if (leftButtonDown == true && leftButtonUp == true)                                                     //when the selection is done 
        {
            rect.width = abs(cor1.x - cor2.x);
            rect.height = abs(cor1.y - cor2.y);
            rect.x = cv::min(cor1.x, cor2.x);
            rect.y = cv::min(cor1.y, cor2.y);
            cv::Mat cutTempImg(img, rect);                                                                      //Selecting a ROI(region of interest) from the original img 
            cv::namedWindow("Cut Temporary Image");
            cv::imshow("Cut Temporary Image", cutTempImg);                                                      //showing the cropped image 
            leftButtonDown = false;
            leftButtonUp = false;
        }
    }
int main(){
    img = cv::imread("image.jpg");
    cv::namedWindow("Original");
    cv::imshow("Original", img);
    cv::setMouseCallback("Original", mouseCall); //setting the mouse callback for selecting the region with mouse  
    while (char(cv::waitKey(1) != 'q')) //waiting for the 'q' key to finish the execution 
    {
    }
    return 0;
}

更改后的代码：

//Program is loading image, and showing it to user. 
//User can use mouse to make a rectangle and cut the loaded image.
//Command line is tracking mouse movements and the coordinates of the rectangle.
//User can end the program using 'q'.

#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>

#include <iostream>
#include <string>

bool leftButtonDown = false, leftButtonUp = false;          //flags for mouse clicks


class ResizeImage {

    cv::Mat img;            //image to process
    cv::Point cor1, cor2;   //coordinates of selected rectangle
    cv::Rect rect;          //rectangle
    std::string name;       //windows name

public:
    //////////////////////////////////////////////////////////////////////////////
    ResizeImage() { std::cout << "Starting..."<<std::endl; };                                   //Constructor/Destructor
    ~ResizeImage() { std::cout << "Ending..." << std::endl; };
    //////////////////////////////////////////////////////////////////////////////
    void setImg(cv::Mat img) { this->img = img; };
    void setImgName(std::string name) { this->name = name; };                                   //set functions
    void setRect();                                             
    void setCoordinates1(int x, int y) { this->cor1.x = x; this->cor1.y = y; };
    void setCoordinates2(int x, int y) { this->cor2.x = x; this->cor2.y = y; };
    //////////////////////////////////////////////////////////////////////////////
    int getCoordinates1X() { return cor1.x; };                                                  //getfunctions
    int getCoordinates1Y() { return cor1.y; };
    int getCoordinates2X() { return cor2.x; };
    int getCoordinates2Y() { return cor2.y; };
    cv::Mat getImg() { return img; };
    std::string getImgName() { return name; };
    //////////////////////////////////////////////////////////////////////////////
    static void mouseCall(int event, int x, int y, int flags, void* param);                     //static function
    //////////////////////////////////////////////////////////////////////////////
    void showImgOriginal();                                                                     //show function (priting image)
    //////////////////////////////////////////////////////////////////////////////

};

void ResizeImage :: showImgOriginal()  {            //showing image
    cv::namedWindow(name, CV_WINDOW_AUTOSIZE);
    cv::imshow(name, img);
};

void ResizeImage::setRect() {                       //calculating selected rectangle
    rect.width = abs(cor1.x - cor2.x);
    rect.height = abs(cor1.y - cor2.y);
    rect.x = cv::min(cor1.x, cor2.x);
    rect.y = cv::min(cor1.y, cor2.y);
}

void ResizeImage::mouseCall(int event, int x, int y, int flags, void* param) {


    if (event == cv::EVENT_LBUTTONDOWN)                                                                                         //finding first corner
    {
        leftButtonDown = true; ((ResizeImage*)param)->cor1.x = x; ((ResizeImage*)param)->cor1.y = y;                            //saving coordinates
        std::cout << "Corner 1: " << ((ResizeImage*)param)->cor1.x << " " << ((ResizeImage*)param)->cor1.y << std::endl;        //printing coordinates
    } 
    if (event == cv::EVENT_LBUTTONUP) {
        if (abs(x - ((ResizeImage*)param)->cor1.x)>20 && abs(y - ((ResizeImage*)param)->cor1.y)>10)                             //finding second corner and checking whether the region is too small 
        {
            leftButtonUp = true; ((ResizeImage*)param)->cor2.x = x; ((ResizeImage*)param)->cor2.y = y;                          //saving coordinates
            std::cout << "Corner 2: " << ((ResizeImage*)param)->cor2.x << " " << ((ResizeImage*)param)->cor2.y << std::endl;    //printing coordinates
        }
        else { std::cout << "Select more than 10 pixels" << std::endl; }                                                        //warning if region is too small
    }  

    if (leftButtonDown == true && leftButtonUp == false)                                                                        //when the left button is down 
    {
        cv::Point pt; pt.x = x; pt.y = y; 
        cv::Mat temp_img = ((ResizeImage*)param)->img.clone();
        rectangle(temp_img, ((ResizeImage*)param)->cor1, pt, cv::Scalar(0, 0, 255));                                            //drawing a rectangle continuously 
    }
    else if (event == cv::EVENT_MOUSEMOVE)                                                                                      //tracking mouse movement
    {
        std::cout << "Mouse moving over the window - position (" << x << ", " << y << ")" << std::endl;

    }
    if (leftButtonDown == true && leftButtonUp == true)                                                                         //when the selection is done 
    {
        ((ResizeImage*)param)->setRect();
        cv::Mat cutTempImg(((ResizeImage*)param)->img, ((ResizeImage*)param)->rect);                                            //Selecting a ROI(region of interest) from the original img 
        cv::namedWindow("Cut Temporary Image");
        cv::imshow("Cut Temporary Image", cutTempImg);                                                                          //showing the cropped image 
        leftButtonDown = false;
        leftButtonUp = false;
    }
}

int main() {

    cv::Mat img = cv::imread("image.jpg");

    ResizeImage img_;

    img_.setImg(img);
    img_.setImgName("Original");
    img_.showImgOriginal();

    cv::setMouseCallback(img_.getImgName(),ResizeImage::mouseCall,&img_);

    while (char(cv::waitKey(1) != 'q')) //waiting for the 'q' key to finish the execution 
    {
    }
    return 0;
}

//程序正在加载图像，并将其显示给用户。
//用户可以使用鼠标制作矩形并剪切加载的图像。
//命令行跟踪鼠标移动和矩形的坐标。
//用户可以使用“q”结束程序。
#包括
#包括
#包括
#包括
#包括
bool leftButtonDown=false，leftButtonUp=false//鼠标点击的标志
类大小图像{
cv:：Mat img；//要处理的图像
cv:：点cor1，cor2；//选定矩形的坐标
cv:：Rect Rect；//矩形
std:：string name；//windows名称
公众：
//////////////////////////////////////////////////////////////////////////////
ResizeImage（）{std:：cout cor2.x=x；this->cor2.y=y；}；
//////////////////////////////////////////////////////////////////////////////
int getCoordinates 1X（）{return cor1.x；}；//getfunctions
int getCoordinates 1y（）{return cor1.y；}；
int getCoordinates 2x（）{return cor2.x；}；
int getCoordinates 2y（）{return cor2.y；}；
cv:：Mat getImg（）{return img；}；
std:：string getImgName（）{return name；}；
//////////////////////////////////////////////////////////////////////////////
静态void mouseCall（int事件、int x、int y、int标志、void*param）；//静态函数
//////////////////////////////////////////////////////////////////////////////
void showImgOriginal（）；//显示函数（翻印图像）
//////////////////////////////////////////////////////////////////////////////
};
void ResizeImage:：showImgOriginal（）{//显示图像
cv:：namedWindow（名称、cv\u窗口\u自动调整大小）；
cv：：imshow（名称，img）；
};
void ResizeImage:：setRect（）{//计算选定矩形
rect.width=abs（cor1.x-cor2.x）；
垂直高度=绝对高度（cor1.y-cor2.y）；
rect.x=cv:：min（cor1.x，cor2.x）；
rect.y=cv:：min（cor1.y，cor2.y）；
}
void ResizeImage:：mouseCall（int事件、int x、int y、int标志、void*param）{
if（event==cv:：event_LBUTTONDOWN）//查找第一个角点
{
leftButtonDown=true；（（ResizeImage*）参数）->cor1.x=x；（（ResizeImage*）参数）->cor1.y=y；//保存坐标
std:：cout cor1.y）>10）//查找第二个角点并检查区域是否太小
{
leftButtonUp=true；（（ResizeImage*）参数）->cor2.x=x；（（ResizeImage*）参数）->cor2.y=y；//保存坐标
std:：cout您应该将函数设置为静态

static void mouseCall(int event, int x, int y, int flags, void* param);

然后：

cv::setMouseCallback(img_.getImgName(),ResizeImage::mouseCall);

如果要将类方法用作回调，确实应该将该方法声明为
static
。但是，还需要向回调传递一个对象，以便能够访问类的非静态成员，例如
cor1
或
cor2

以下是如何实现这一目标的一个简单示例：

class Call {
public:
    Call(int i) : a(i){};
    int a;

    static void mouse(int event, int x, int y, int flags, void* param) {
        std::cout << ((Call*)param)->a << std::endl;
    }
};


cv::namedWindow("Call");

Call call(10);
cv::setMouseCallback("Call", Call::mouse, &call);

cv::imshow("Call", cv::Mat(100, 100, CV_8U, cv::Scalar(0)));
cv::waitKey();

类调用{
公众：
调用（inti）：a（i）{}；
INTA；
静态无效鼠标（int事件、int x、int y、int标志、void*param）{
标准：：cout a
class Call {
public:
    Call(int i) : a(i){};
    int a;

    static void mouse(int event, int x, int y, int flags, void* param) {
        std::cout << ((Call*)param)->a << std::endl;
    }
};


cv::namedWindow("Call");

Call call(10);
cv::setMouseCallback("Call", Call::mouse, &call);

cv::imshow("Call", cv::Mat(100, 100, CV_8U, cv::Scalar(0)));
cv::waitKey();