opencv 3.0 鼠标操作 setMouseCallback

网上有贴出opencv中 setMouseCallback 的参数表

http://blog.csdn.net/u011642774/article/details/26710293

但是对于怎么用的，却没有太多实例

不多说，上代码：

 

值得注意的是：（调试N久才发现的大教训！）

以前用imshow，都不一定先调用nameWindow，

而这里必须先调用nameWindow，再使用setMouseCallback。

否则setMouseCallback不会运作的。

 

void leftClick(int event, int x, int y, int flag,void* param){    if (event != EVENT_LBUTTONDOWN)    {        return;    }    Point *ptr = (Point*)param;    ptr->x = x;    ptr->y = y;}void setMouseCallback_test(){    Point p_click;//最好加static， 避免有时数据赋值后被释放    //读取图片    const char* imagename = "E:/1.jpg";       Mat img = cv::imread(imagename);         if(img.empty())       {           fprintf(stderr, "Can not load image %s\n", imagename);       }    if( !img.data )         //显示窗口    namedWindow("image");   //不能省略，否则setMouseCallback不运行    imshow("image", img);    while (1)    {        setMouseCallback( "image", leftClick, &p_click);        printf("%d\n",p_click.x);        printf("%d\n",p_click.y);        waitKey(1);    }}

 

后来又发现有事，在定义的函数中调用setMouseCallback，Point  p_click 可能回无效。

调试了N久，居然发现是数据会在获取后被销毁。

于是乎最稳妥的办法是在Point  p_click前加static
 

复杂点的例子：

测量点的空间间距

void leftClick(int event, int x, int y, int flag,void* param){    if (event != EVENT_LBUTTONDOWN)    {        return;    }    Point *ptr = (Point*)param;    ptr->x = x;    ptr->y = y;}void cal_distance(CAL_V &cal_V){    static Point    pre_click, cur_click;    const char      fil_D = 2;     //滤波半径    Point3d         pt, p1, p2;    Mat             ROI_32f;    setMouseCallback( "Amplitude", leftClick, &(cur_click));    cur_click.x /= 2;   //显示的图像坐标有被放大过     cur_click.y /= 2;     if (px_in_range(cur_click) == 1)    {        if (px_in_range(pre_click) == 0)        {            pre_click = cur_click;            //画点1            cal_V.amp_8U.ptr<uchar>(cur_click.y)[cur_click.x] = 0;            printf("Point 1：（%d,%d）\n", cur_click.x, cur_click.y);        }        else        {            //画点2            cal_V.amp_8U.ptr<uchar>(cur_click.y)[cur_click.x] = 0;            printf("Point 2：（%d,%d）\n", cur_click.x, cur_click.y);            //计算点的间距            pt.x = pre_click.x;            pt.y = pre_click.y;            ROI_32f = cal_V.depth_32F(Rect((int)pt.x - fil_D, (int)pt.y - fil_D, (fil_D*2+1), (fil_D*2+1)));            pt.z = medianElem<float>(ROI_32f);            p1 = cal_worldpoint(pt,cal_V.cameraMatrix);            pt.x = cur_click.x;            pt.y = cur_click.y;            ROI_32f = cal_V.depth_32F(Rect((int)pt.x - fil_D, (int)pt.y - fil_D, (fil_D*2+1), (fil_D*2+1)));            pt.z = medianElem<float>(ROI_32f);            p2 = cal_worldpoint(pt,cal_V.cameraMatrix);            cout << "Distance: " << norm(p2 - p1) << " mm"<<endl;            pre_click.x = 0;            pre_click.y = 0;        }    }    cur_click.x = 0;     cur_click.y = 0;     waitKey(1);}

 再深入一点，多次点击界面。用于框选区域。

//检测左键按下void leftClick(int event, int x, int y, int flag,void* param){    if (event != EVENT_LBUTTONDOWN)    {        return;    }    Point *ptr = (Point*)param;    ptr->x = x;    ptr->y = y;}//获取左键点void getPoint(char * win, Point *pt, Mat &img, Scalar color){    setMouseCallback(win, leftClick, pt);    while (*pt == Point(-1,-1))    {        waitKey(10);    }    //画点    circle(img, *pt, 3, color, 2);    imshow(win, img);    waitKey(1);    cout <<"Click: "<< *pt << " " << endl;}void multi_click_test(){    const char* imagename = "E:/Hydrangeas.jpg";    Mat img = imread(imagename);    Point p_click[4];    p_click[0] = p_click[1] = p_click[2] = p_click[3] = Point(-1,-1);    //鼠标点击取区域    namedWindow("Image");    imshow("Image", img);    getPoint("Image", p_click  , img, Scalar(0,0,0));    getPoint("Image", p_click+1, img, Scalar(0,0,0));    getPoint("Image", p_click+2, img, Scalar(0,0,0));    getPoint("Image", p_click+3, img, Scalar(0,0,0));    line(img, p_click[0], p_click[1], Scalar(255,255,255));    line(img, p_click[2], p_click[1], Scalar(255,255,255));    line(img, p_click[2], p_click[3], Scalar(255,255,255));    line(img, p_click[0], p_click[3], Scalar(255,255,255));    imshow("Image", img);    waitKey();}

输出和效果图如下：