Opening and Displaying an Image in C++?

问题:

Basically I am teaching myself C++ and part of the program function will be to open and close an image specified. How would I go about doing this? Or what resource would I use?

Thanks!

回答1:

In c++ (without any extra library) you may open an image. But there will be nothing particularly useful except a bunch of binary data. then you have to use your own decoder If you use opencv you can write to open an image and display it:

Mat m("fileName");
imshow("windowName",m);

To do the same with a general purpose library like qt you can use this code :

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QGraphicsScene scene;
    QGraphicsView view(&scene);
    QGraphicsPixmapItem item(QPixmap("c:\\test.png"));
    scene.addItem(&item);
    view.show();
    return a.exec();
}

To learn more about imageviewer widget go here. Or you may have a look at here to display as graphics view.

回答2:

For a crossplatform, opensource and very good library you can use libmagick++.

回答3:

modified Hello World sample from OpenCV 2 Computer Vision Application Programming Cookbook running in VS 2012 win32 Console app

or official OpenCV (Open Source) sample

warning: opencv-2.4.10.exe Win installer is 360 MB which have many advance features and have sample code, Doc and built binaries in Python and Java too x86 and 64 in it too

#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>    

int main()
{        
    // read an image
    cv::Mat image= cv::imread("img.jpg");   
    // create image window named "My Image"
    cv::namedWindow("My Image");
    // show the image on window
    cv::imshow("My Image", image);
    // wait key for 5000 ms
    cv::waitKey(5000);

    return 0;
}