openCV学习笔记（四） —— 鼠标截图、滑动条播放视频

偏执的太偏执、 2021-09-27 04:30 202阅读 0赞

一、鼠标截图

#include <iostream>
    #include "opencv2/opencv.hpp"
    
    using namespace std;
    using namespace cv;
    
    
    Mat inImage = imread("test.jpg");
    Mat outImage = inImage.clone();
    bool flag = false;
    Point pt;
    Mat ROI;
    
    void onMouse(int event, int x, int y, int flag, void *param)
    {
    	switch (event)
    	{
    	case CV_EVENT_LBUTTONDOWN:	//鼠标左键按下
    		printf("鼠标左键按下\n");
    
    		flag = true;
    		pt.x = x;
    		pt.y = y;
    		break;
    
    	case CV_EVENT_MOUSEMOVE:
    		printf("鼠标移动\n");
    
    		if (flag)
    		{
    			inImage.copyTo(outImage); //将原图像赋值给temp，以便永远只有一个矩形（否则许多矩形会重叠在一起）
    			rectangle(outImage, pt, Point(x, y), Scalar(0, 255, 0), 2, 8);
    		}
    		break;
    
    	case CV_EVENT_LBUTTONUP:
    		printf("鼠标左键抬起\n");
    
    		flag = false;
    		ROI = outImage(Rect(pt.x, pt.y, x - pt.x, y - pt.y));	//确定ROI区域,有矩形边框
    		//ROI = inImage(Rect(pt.x, pt.y, x - pt.x, y - pt.y));//无矩形边框
    		imshow("Out", ROI);
    		imwrite("ROI.jpg", ROI);
    		break;
    
    	default:
    		break;
    	}
    }
    
    int main()
    {
    	namedWindow("inWindows", CV_WINDOW_AUTOSIZE);
    	
    	setMouseCallback("inWindows", onMouse, 0);
    
    	while (1)
    	{
    		imshow("inWindows", outImage);
    		if (27 == waitKey(30))
    		{
    			break;
    		}
    	}
    
    	destroyAllWindows();
    	return 0;
    }

![70][]

二、滑动条播放视频

/*
    	滑动条视频播放
    */
    #include <iostream>
    #include "opencv2/opencv.hpp"
    
    using namespace std;
    using namespace cv;
    
    
    int value;
    
    void onChange(int pos, void *param)
    {
    	VideoCapture cap = *(VideoCapture *)param;
    	cap.set(CV_CAP_PROP_POS_FRAMES, value);	//设置视频帧位置
    }
    
    int main()
    {
    	Mat frame;
    	VideoCapture capture;
    
    	capture.open("test.avi");
    	if (!capture.isOpened())
    	{
    		printf("can't open video file\n");
    		return -1;
    	}
    
    	int fps = (int)capture.get(CV_CAP_PROP_FPS);	//获取视频帧率
    	int frameCount = (int)capture.get(CV_CAP_PROP_FRAME_COUNT);	//获取视频总帧数
    
    	namedWindow("video", CV_WINDOW_AUTOSIZE);
    
    	createTrackbar("frame", "video", &value, frameCount, onChange, (void *)&capture);
    
    	while (true)
    	{
    		int framePos = (int)capture.get(CV_CAP_PROP_POS_FRAMES);
    		setTrackbarPos("frame", "video", framePos);
    		capture.read(frame);
    		imshow("video", frame);
    		if (27 == waitKey(1000 / fps))
    		{
    			break;
    		}
    	}
    
    	capture.release();
    	destroyAllWindows();
    	
    	return 0;
    }

[70]: /images/20210923/29c00c6ebcdd4696912dedd59618b806.png