opencv学习之路鼠标截图，滑动条播放视频

Posted 2020-09-28 进击的小猴子

一、鼠标截图

 1 #include<opencv2/opencv.hpp>
 2 #include<iostream>
 3 using namespace cv;
 4 using namespace std;
 5 
 6 Mat img=imread("E://1.jpg");
 7 Mat temp=img.clone();
 8 Mat ROI;
 9 Point pt;
10 bool flag=false;
11 
12 void onMouse(int event,int x,int y,int flag,void* param){
13     switch (event)
14     {
15     case CV_EVENT_LBUTTONDOWN://鼠标左键按下
16         //cout<<"鼠标左键按下"<<endl;
17         flag=true;
18         pt.x=x;
19         pt.y=y;
20         break;
21     case CV_EVENT_MOUSEMOVE://鼠标移动
22         //cout<<"鼠标移动"<<endl;
23         if(flag){
24             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）
25             rectangle(img,pt,Point(x,y),Scalar(0,255,0),2,8);
26         }
27         break;
28     case CV_EVENT_LBUTTONUP://鼠标左键抬起
29         //cout<<"鼠标抬起"<<endl;
30         flag=false;
31         //ROI=img(Rect(pt.x,pt.y,x-pt.x,y-pt.y));//确定ROI区域,有矩形边框
32         ROI=temp(Rect(pt.x,pt.y,x-pt.x,y-pt.y));//无矩形边框
33         imshow("ROI",ROI);
34         imwrite("E://ROI.jpg",ROI);
35         break;
36     default:
37         break;
38     }
39 }
40 
41 void main(){
42     namedWindow("mouse",CV_WINDOW_AUTOSIZE);
43     setMouseCallback("mouse",onMouse,0);
44     while(1){
45         imshow("mouse",img);
46         if(27==waitKey(10))//esc跳出循环
47             break;
48     }
49 }

 

二、滑动条视频播放

 1 #include<opencv2/opencv.hpp>
 2 #include<iostream>
 3 using namespace cv;
 4 using namespace std;
 5 
 6 int value;
 7 void onChange(int,void* param){
 8     VideoCapture cap=*(VideoCapture*)param;
 9     cap.set(CV_CAP_PROP_POS_FRAMES,value);//设置视频帧位置
10 }
11 
12 void main(){
13     Mat frame;
14     char strFps[20];
15     VideoCapture cap("E://2.avi");
16     namedWindow("video",CV_WINDOW_AUTOSIZE);
17     int frameCount=cap.get(CV_CAP_PROP_FRAME_COUNT);//获取视频总帧数
18     createTrackbar("Frame","video",&value,frameCount,onChange,&cap);
19 
20     if(cap.isOpened()){//如果视频成功打开
21         while(1){
22             double Fps=cap.get(CV_CAP_PROP_FPS);//获得视频帧率
23             sprintf(strFps,"Fps%0.1f/s",Fps);//格式化字符串
24             int framePos=cap.get(CV_CAP_PROP_POS_FRAMES);//获取视频帧位置
25             setTrackbarPos("Frame","video",framePos);//设置滑动条位置
26             cap>>frame;
27             if(!frame.empty()){//如果该帧不为空
28                 putText(frame,strFps,Point(5,30),CV_FONT_HERSHEY_COMPLEX_SMALL,1,Scalar(0,255,0),2,8);
29                 imshow("video",frame);
30                 if(27==waitKey(1000/Fps))//esc退出，1000/Fps毫秒刷新
31                     break;
32             }
33         }
34     }
35 }