一.? 学习并掌握可执行程序的编译、组装过程。

1.先前准备

main.c

?x2x.c

.x2y.c

2.静态库链接

.先gcc -c main.c

gcc -c x2x.c

gcc -c x2y.c

然后ar -crv libmyx.a x2x.o x2y.o

然后gcc -o xx main.c libmyx.a（xx为重命名名字）

最后./xx

输出结果如下

通过静态库链接生成的可执行程序的大小

为8.4kb(8416字节）

?3.动态库链接

通过命令

gcc -shared -fPIC -o libmyx.so x2x.o x2y.o

生成动态库文件，命令

gcc main.c libmyx.so -o xx2

结果如下

通过动态库链接生成的可执行程序的大小

为8.4kb（8360字节）

可以看出相对与静态库链接少了56字节

?二.opencv下载

详情见教程链接：?opencv安装教程

?1.图片

#include <opencv2/highgui.hpp>
#include <opencv2/opencv.hpp>
using namespace cv;
using namespace std;
int main(int argc, char** argv)
{
	CvPoint center;
    double scale = -3; 

	IplImage* image = cvLoadImage("flower.jpg");
	argc == 2? cvLoadImage(argv[1]) : 0;
	
	cvShowImage("Image", image);
	
	
	if (!image) return -1; 	center = cvPoint(image->width / 2, image->height / 2);
	for (int i = 0;i<image->height;i++)
		for (int j = 0;j<image->width;j++) {
			double dx = (double)(j - center.x) / center.x;
			double dy = (double)(i - center.y) / center.y;
			double weight = exp((dx*dx + dy*dy)*scale);
			uchar* ptr = &CV_IMAGE_ELEM(image, uchar, i, j * 3);
			ptr[0] = cvRound(ptr[0] * weight);
			ptr[1] = cvRound(ptr[1] * weight);
			ptr[2] = cvRound(ptr[2] * weight);
		}

	Mat src;Mat dst;
	src = cvarrToMat(image);
	cv::imwrite("test.png", src);

    cvNamedWindow("test",1);  	imshow("test", src);
	 cvWaitKey();
	 return 0;
}

text代码?

#include <opencv2/highgui.hpp>
#include <opencv2/opencv.hpp>
using namespace cv;
using namespace std;
int main(int argc, char** argv)
{
?? ?CvPoint center;
? ? double scale = -3;?

?? ?IplImage* image = cvLoadImage("flower.jpg");
?? ?argc == 2? cvLoadImage(argv[1]) : 0;
?? ?
?? ?cvShowImage("Image", image);
?? ?
?? ?
?? ?if (!image) return -1; ?? ?center = cvPoint(image->width / 2, image->height / 2);
?? ?for (int i = 0;i<image->height;i++)
?? ??? ?for (int j = 0;j<image->width;j++) {
?? ??? ??? ?double dx = (double)(j - center.x) / center.x;
?? ??? ??? ?double dy = (double)(i - center.y) / center.y;
?? ??? ??? ?double weight = exp((dx*dx + dy*dy)*scale);
?? ??? ??? ?uchar* ptr = &CV_IMAGE_ELEM(image, uchar, i, j * 3);
?? ??? ??? ?ptr[0] = cvRound(ptr[0] * weight);
?? ??? ??? ?ptr[1] = cvRound(ptr[1] * weight);
?? ??? ??? ?ptr[2] = cvRound(ptr[2] * weight);
?? ??? ?}

?? ?Mat src;Mat dst;
?? ?src = cvarrToMat(image);
?? ?cv::imwrite("test.png", src);

? ? cvNamedWindow("test",1); ??? ?imshow("test", src);
?? ? cvWaitKey();
?? ? return 0;
}

再在code文件夹中准备flower.jpg文件

2.视频

再次在code文件夹下打开命令行，新建test2.cpp文件
test2.cpp

/*********************************************************************
打开电脑摄像头，空格控制视频录制，ESC退出并保存视频RecordVideo.avi
*********************************************************************/
#include<iostream>
#include <opencv2/opencv.hpp>
#include<opencv2/core/core.hpp>
#include<opencv2/highgui/highgui.hpp>
using namespace cv;
using namespace std;

int main()
{
	//打开电脑摄像头
	VideoCapture cap(0);
	if (!cap.isOpened())
	{
		cout << "error" << endl;
		waitKey(0);
		return 0;
	}

	//获得cap的分辨率
	int w = static_cast<int>(cap.get(CV_CAP_PROP_FRAME_WIDTH));
	int h = static_cast<int>(cap.get(CV_CAP_PROP_FRAME_HEIGHT));
	Size videoSize(w, h);
	VideoWriter writer("RecordVideo.avi", CV_FOURCC('M', 'J', 'P', 'G'), 25, videoSize);
	
	Mat frame;
	int key;//记录键盘按键
	char startOrStop = 1;//0  开始录制视频； 1 结束录制视频
	char flag = 0;//正在录制标志 0-不在录制； 1-正在录制

	while (1)
	{
		cap >> frame;
		key = waitKey(100);
		if (key == 32)//按下空格开始录制、暂停录制   可以来回切换
		{
			startOrStop = 1 - startOrStop;
			if (startOrStop == 0)
			{
				flag = 1;
			}
		}
		if (key == 27)//按下ESC退出整个程序，保存视频文件到磁盘
		{
			break;
		}

		if (startOrStop == 0 && flag==1)
		{
			writer << frame;
			cout << "recording" << endl;
		}
		else if (startOrStop == 1)
		{
			flag = 0;
			cout << "end recording" << endl;
			
		}
		imshow("picture", frame);
	}
	cap.release();
	writer.release();
	destroyAllWindows();
	return 0;
}

g++ test2.cpp -o test2 `pkg-config --cflags --libs opencv`