opencv学习（1）

#include <iostream>
//#include <opencv2/opencv.hpp>
#include <opencv2/highgui/highgui.hpp>

using namespace cv;
using namespace std;


int g_slider_position = 0;
int g_run = 1, g_dontset = 0;
VideoCapture g_cap;

int show_image() {

    cv::Mat img =  cv::imread("/home/unicoe/CLionProjects/opencv/test1/img/example.jpg");


    if(img.empty()) return -1;

    cv::namedWindow("window", cv::WINDOW_AUTOSIZE);

    cv::imshow("window", img);

    cv::waitKey(3000);

    cv::destroyWindow("window");

    std::cout << "Hello, opencv!" << std::endl;
    return 0;
}

/*
 * 其中 #include<opencv2/opencv.hpp>
 * 包含了所有的 opencv所包含的库
 *
 *
 * imread 能使用的图片格式
 * including BMP, DIB, JPEG, JPE, PNG, PBM, PGM, PPM, SR, RAS, and TIFF.
 * */


int show_vedio()
{
    namedWindow("video", WINDOW_AUTOSIZE);
    VideoCapture cap;
    cap.open("/home/unicoe/CLionProjects/opencv/test1/vedio/example.flv");

    Mat frame;

    for(;;){

        cap >> frame;
        if (frame.empty()) break;
        imshow("video", frame);
        if(waitKey(33)>=0) break;
    }
    return 0;
}


void onTrackbarSlider(int pos, void *)
{
    g_cap.set(CAP_PROP_POS_FRAMES, pos);
    if(!g_dontset)
        g_run = 1;
    g_dontset = 0;
}

int show_TrackbarSlider()
{
    namedWindow("TrackbarSlider", WINDOW_NORMAL);

    g_cap.open("/home/unicoe/CLionProjects/opencv/test1/vedio/example.flv");
    int frames = (int) g_cap.get(CAP_PROP_FRAME_COUNT);
    int tmpw = (int)g_cap.get(CAP_PROP_FRAME_WIDTH);
    int tmph = (int)g_cap.get(CAP_PROP_FRAME_HEIGHT);

    cout << "video has " << frames << " frames of dimensions ( " << tmpw << " , " << tmph << ")."<<endl;

    createTrackbar("Position", "TrackbarSlider", &g_slider_position, frames, onTrackbarSlider);

    Mat frame;
    for(;;)
    {
        if(g_run != 0)
        {
            g_cap >> frame; if(frame.empty()) break;
            int cur_pos = (int) g_cap.get(CAP_PROP_POS_FRAMES);
            g_dontset = 1;

            setTrackbarPos("Position", "TrackbarSlider", cur_pos);
            imshow("TrackbarSlider", frame);

            g_run = -1;
        }

        char c = (char) waitKey(10);

        if(c == 's')
        {
            g_run = 1; cout << "single step, run = " << g_run << endl;
        }
        if(c == 'r')
        {
            g_run = -1; cout << "run mode, run = " << g_run << endl;
        }
        if(c == 27)
            break;

    }
    return 0;
}

/// page 31

int main()
{
    //show_vedio();
    //show_image();
    show_TrackbarSlider();
    return 0;
}

　　

#include <opencv2/opencv.hpp>  包含了opencv中所有的头文件

　　

cv::Mat 是存放图片的数据类型

cv::imread() 用来读取图片

cv::nameWindow() 用来定义窗口

cv::imshow() 用来显示图片

cv::waitkey() 用来定义退出时间

cv::destroyWindow() 用来销毁窗口

cv::VideoCapture 用来捕捉视频对象，使视频对象实例化

cap.open() 打开一个视频文件

cv::createTrackbar() 用来定义一个进度条