使用imshow opencv将图像拟合到屏幕

Question

I want to display an image using opencv on Mac os X 13'. The image size is 1920 × 1080. When I run this code, I see just a part of an image. I need to fit the image to the screen.

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include<opencv2/core/core.hpp>
#include<opencv2/highgui/highgui.hpp>
#include "opencv2/opencv.hpp"
#include<string.h>
using namespace cv;
using namespace std;

int main()
{
   Mat image=imread("/Users/rafikgouiaa/Qt/projects/MakeVideo/build-MakeVideo-    Desktop_Qt_5_0_2_clang_64bit-Debug/im.jpg");
   namedWindow( "Display frame",CV_WINDOW_AUTOSIZE);
   imshow("Display frame", image);
   waitKey(0);
   return 0
}

Answer 1

If you need to show an image that is bigger than the screen resolution, you will need to call

namedWindow("Display frame", WINDOW_NORMAL)

before the imshow.

To set desirable size of the window call please

cv::resizeWindow("Display frame", WIDTH, HEIGHT);

For more details see http://docs.opencv.org/modules/highgui/doc/user_interface.html#imshow

Answer 2

Passing CV_WINDOW_AUTOSIZE to namedWindow() will make the window size automatically adjust to fit the displayed image. And you see part of the image is probably because the image is too large for your screen.

To work out, you can first resize the image to smaller size. Like this:

Mat image=imread("...");
resize(image, image, Size(image.cols/2, image.rows/2)); // to half size or even smaller
namedWindow( "Display frame",CV_WINDOW_AUTOSIZE);
imshow("Display frame", image);

Answer 3

您需要将CV_WINDOW_OPENGL改为CV_WINDOW_AUTOSIZE