Opencv鼠标事件
Opencv中的鼠标事件，例如在界面中通过鼠标左键任意位置，显示点坐标，并将改点存储到points中，为后续使用。
定义鼠标事件：
#include "opencv2/core.hpp"
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
cv::Mat org,dst,img,tmp;
std::vector points;
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 cv::Point pre_pt = cv::Point(-1,-1);//初始坐标
static cv::Point cur_pt = cv::Point(-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 = cv::Point(x,y);
cv::putText(org,temp,pre_pt,cv::FONT_HERSHEY_SIMPLEX,0.5,cv::Scalar(0,0,0,255),1,8);//在窗口上显示坐标
cv::circle(org,pre_pt,2,cv::Scalar(255,0,0,0),CV_FILLED,CV_AA,0);//划圆
cv::imshow("img",org);
}
else if(event == cv::EVENT_LBUTTONUP){
Point p;
p.x = x;
p.y = y;
points.push_back(p);
// std::cout<<"mouse button up"< 调用鼠标事件
在main函数中调用鼠标事件：
org = cv::Mat(480, 640, CV_8UC3, cv::Scalar(255, 255,255));
cv::namedWindow("img");
cv::setMouseCallback("img",on_mouse,0);//调用回调函数
cv::imshow("img", org);
char key = cv::waitKey(0);
最后的效果为：
备注：Opencv中关于所有鼠标事件定义如下：
EVENT_MOUSEMOVE = 0, //!< indicates that the mouse pointer has moved over the window.
EVENT_LBUTTONDOWN = 1, //!< indicates that the left mouse button is pressed.
EVENT_RBUTTONDOWN = 2, //!< indicates that the right mouse button is pressed.
EVENT_MBUTTONDOWN = 3, //!< indicates that the middle mouse button is pressed.
EVENT_LBUTTONUP = 4, //!< indicates that left mouse button is released.
EVENT_RBUTTONUP = 5, //!< indicates that right mouse button is released.
EVENT_MBUTTONUP = 6, //!< indicates that middle mouse button is released.
EVENT_LBUTTONDBLCLK = 7, //!< indicates that left mouse button is double clicked.
EVENT_RBUTTONDBLCLK = 8, //!< indicates that right mouse button is double clicked.
EVENT_MBUTTONDBLCLK = 9, //!< indicates that middle mouse button is double clicked.
EVENT_MOUSEWHEEL = 10,//!< positive and negative values mean forward and backward scrolling, respectively.
EVENT_MOUSEHWHEEL = 11 //!< positive and negative values mean right and left scrolling, respectively.