鼠标操作

1、setMouseCallback函数

用于创建鼠标响应函数

调用形式：

C++: void setMouseCallback(const string& winname, MouseCallback onMouse, void* userdata=0 )

const string& winname：窗口名称

MouseCallback onMouse：鼠标响应调用的函数

void* userdata=0:一般选择默认0

2、opencv例子：

程序如下，已经附上说明：

 #include <opencv2/core/core.hpp>
 #include <opencv2/highgui/highgui.hpp>
 #include <stdio.h>

 using namespace cv;

 cv::Mat org,dst,img,tmp;
 void on_mouse(int event,int x,int y,int flags,void *ustc)//event鼠标事件代号，x,y鼠标坐标，flags拖拽和键盘操作的代号
 {
     static Point pre_pt = (-1,-1);//初始坐标
     static Point cur_pt = (-1,-1);//实时坐标
     char temp[16];
     if (event == CV_EVENT_LBUTTONDOWN)//左键按下，读取初始坐标，并在图像上该点处划圆
     {
         org.copyTo(img);//将原始图片复制到img中
         sprintf(temp,"(%d,%d)",x,y);
         pre_pt = Point(x,y);
         putText(img,temp,pre_pt,FONT_HERSHEY_SIMPLEX,0.5,Scalar(0,0,0,255),1,8);//在窗口上显示坐标
         circle(img,pre_pt,2,Scalar(255,0,0,0),CV_FILLED,CV_AA,0);//划圆
         imshow("img",img);
     }
     else if (event == CV_EVENT_MOUSEMOVE && !(flags & CV_EVENT_FLAG_LBUTTON))//左键没有按下的情况下鼠标移动的处理函数
     {
         img.copyTo(tmp);//将img复制到临时图像tmp上，用于显示实时坐标
         sprintf(temp,"(%d,%d)",x,y);
         cur_pt = Point(x,y);
         putText(tmp,temp,cur_pt,FONT_HERSHEY_SIMPLEX,0.5,Scalar(0,0,0,255));//只是实时显示鼠标移动的坐标
         imshow("img",tmp);
     }
     else if (event == CV_EVENT_MOUSEMOVE && (flags & CV_EVENT_FLAG_LBUTTON))//左键按下时，鼠标移动，则在图像上划矩形
     {
         img.copyTo(tmp);
         sprintf(temp,"(%d,%d)",x,y);
         cur_pt = Point(x,y);
         putText(tmp,temp,cur_pt,FONT_HERSHEY_SIMPLEX,0.5,Scalar(0,0,0,255));
         rectangle(tmp,pre_pt,cur_pt,Scalar(0,255,0,0),1,8,0);//在临时图像上实时显示鼠标拖动时形成的矩形
         imshow("img",tmp);
     }
     else if (event == CV_EVENT_LBUTTONUP)//左键松开，将在图像上划矩形
     {
         org.copyTo(img);
         sprintf(temp,"(%d,%d)",x,y);
         cur_pt = Point(x,y);
         putText(img,temp,cur_pt,FONT_HERSHEY_SIMPLEX,0.5,Scalar(0,0,0,255));
         circle(img,pre_pt,2,Scalar(255,0,0,0),CV_FILLED,CV_AA,0);
         rectangle(img,pre_pt,cur_pt,Scalar(0,255,0,0),1,8,0);//根据初始点和结束点，将矩形画到img上
         imshow("img",img);
         img.copyTo(tmp);
         //截取矩形包围的图像，并保存到dst中
         int width = abs(pre_pt.x - cur_pt.x);
         int height = abs(pre_pt.y - cur_pt.y);
         if (width == 0 || height == 0)
         {
             printf("width == 0 || height == 0");
             return;
         }
         dst = org(Rect(min(cur_pt.x,pre_pt.x),min(cur_pt.y,pre_pt.y),width,height));
         namedWindow("dst");
         imshow("dst",dst);
         waitKey(0);
     }
 }
 void main()
 {
     org = imread("1.jpg");
     org.copyTo(img);
     org.copyTo(tmp);
     namedWindow("img");//定义一个img窗口
     setMouseCallback("img",on_mouse,0);//调用回调函数
     imshow("img",img);
     cv::waitKey(0);
 }