System Information

OpenCV version: 4.x branch ( 2cd3304 )
Operating System / Platform: Ubuntu 24.04
Compiler & compiler version: GCC 13.2

Detailed description

We can use imshow() with window which is not created by namedWindow().

https://docs.opencv.org/4.x/d7/dfc/group__highgui.html#ga453d42fe4cb60e5723281a89973ee563

If the window was not created before this function, it is assumed creating a window with cv::WINDOW_AUTOSIZE.

It works well with GTK3 highgui-backed.
However it doesn't work well with Wayland highgui-backend.

Steps to reproduce

opencv-log.png is copied from opencv/docs folder.

// g++ main.cpp -o a.out -I /usr/local/include/opencv4 -lopencv_core -lopencv_highgui -lopencv_imgcodecs
#include <opencv2/core.hpp>
#include <opencv2/highgui.hpp>
#include <opencv2/imgcodecs.hpp>
#include <iostream>
#include <string>
 
int main(void)
{
  std::cout << "cv::currentUIFramework() returns " << cv::currentUIFramework() << std::endl; 

  cv::Mat src;
  src = cv::imread("opencv-logo.png");
 
  // cv::namedWindow("src");
 
  int key = 0;
  do
  {
      cv::imshow("src", src );
      key = cv::waitKey(50);
  } while( key != 'q' );
  return 0;
}

Issue submission checklist

• I report the issue, it's not a question
• I checked the problem with documentation, FAQ, open issues, forum.opencv.org, Stack Overflow, etc and have not found any solution
• I updated to the latest OpenCV version and the issue is still there
• There is reproducer code and related data files (videos, images, onnx, etc)