opencv学习之路（6）、鼠标截图，滑动条播放视频

一、鼠标截图

 #include<opencv2/opencv.hpp>
 #include<iostream>
 using namespace cv;
 using namespace std;
 
 Mat img=imread("E://1.jpg");
 Mat temp=img.clone();
 Mat ROI;
 Point pt;
 bool flag=false;
 
 void onMouse(int event,int x,int y,int flag,void* param){
     switch (event)
     {
     case CV_EVENT_LBUTTONDOWN://鼠标左键按下
         //cout<<"鼠标左键按下"<<endl;
         flag=true;
         pt.x=x;
         pt.y=y;
         break;
     case CV_EVENT_MOUSEMOVE://鼠标移动
         //cout<<"鼠标移动"<<endl;
         if(flag){
             temp.copyTo(img);//temp复制给img（相当于恢复成原图），以便永远只有一个矩形（否则许多矩形会重叠在一起）
             rectangle(img,pt,Point(x,y),Scalar(,,),,);
         }
         break;
     case CV_EVENT_LBUTTONUP://鼠标左键抬起
         //cout<<"鼠标抬起"<<endl;
         flag=false;
         //ROI=img(Rect(pt.x,pt.y,x-pt.x,y-pt.y));//确定ROI区域,有矩形边框
         ROI=temp(Rect(pt.x,pt.y,x-pt.x,y-pt.y));//无矩形边框
         imshow("ROI",ROI);
         imwrite("E://ROI.jpg",ROI);
         break;
     default:
         break;
     }
 }
 
 void main(){
     namedWindow("mouse",CV_WINDOW_AUTOSIZE);
     setMouseCallback("mouse",onMouse,);
     while(){
         imshow("mouse",img);
         if(==waitKey())//esc跳出循环
             break;
     }
 }

二、滑动条视频播放

 #include<opencv2/opencv.hpp>
 #include<iostream>
 using namespace cv;
 using namespace std;
 
 int value;
 void onChange(int,void* param){
     VideoCapture cap=*(VideoCapture*)param;
     cap.set(CV_CAP_PROP_POS_FRAMES,value);//设置视频帧位置
 }
 
 void main(){
     Mat frame;
     char strFps[];
     VideoCapture cap("E://2.avi");
     namedWindow("video",CV_WINDOW_AUTOSIZE);
     int frameCount=cap.get(CV_CAP_PROP_FRAME_COUNT);//获取视频总帧数
     createTrackbar("Frame","video",&value,frameCount,onChange,&cap);
 
     if(cap.isOpened()){//如果视频成功打开
         while(){
             double Fps=cap.get(CV_CAP_PROP_FPS);//获得视频帧率
             sprintf(strFps,"Fps%0.1f/s",Fps);//格式化字符串
             int framePos=cap.get(CV_CAP_PROP_POS_FRAMES);//获取视频帧位置
             setTrackbarPos("Frame","video",framePos);//设置滑动条位置
             cap>>frame;
             if(!frame.empty()){//如果该帧不为空
                 putText(frame,strFps,Point(,),CV_FONT_HERSHEY_COMPLEX_SMALL,,Scalar(,,),,);
                 imshow("video",frame);
                 if(==waitKey(/Fps))//esc退出，1000/Fps毫秒刷新
                     break;
             }
         }
     }
 }