Merge branch '4.x' into '5.x'

doc/tutorials/app/highgui_wayland_ubuntu.markdown

@@ -0,0 +1,106 @@
+Using Wayland highgui-backend in Ubuntu {#tutorial_wayland_ubuntu}
+=======================================
+
+@tableofcontents
+
+@prev_tutorial{tutorial_intelperc}
+
+|    |    |
+| -: | :- |
+| Original author | Kumataro |
+| Compatibility | OpenCV >= 4.10 |
+| ^ | Ubuntu 24.04 |
+
+Goal
+-----
+This tutorial is to use Wayland highgui-backend in Ubuntu 24.04.
+
+Wayland highgui-backend is experimental implementation.
+
+Setup
+-----
+- Setup Ubuntu 24.04.
+- `sudo apt install build-essential git cmake` to build OpenCV.
+- `sudo apt install libwayland-dev wayland-protocols libxkbcommon-dev` to enable Wayland highgui-backend.
+- (Option) `sudo apt install ninja-build` (or remove `-GNinja` option for cmake command).
+- (Option) `sudo apt install libwayland-egl1` to enable Wayland EGL library.
+
+Get OpenCV from GitHub
+----------------------
+
+```bash
+mkdir work
+cd work
+git clone --depth=1 https://github.com/opencv/opencv.git
+```
+
+@note
+`--depth=1` option is to limit downloading commits. If you want to see more commit history, please remove this option.
+
+Build/Install OpenCV with Wayland highgui-backend
+-------------------------------------------------
+
+Run `cmake` with `-DWITH_WAYLAND=ON` option to configure OpenCV.
+
+```bash
+cmake -S opencv -B build4-main -DWITH_WAYLAND=ON -GNinja
+```
+
+If succeeded, Wayland Client/Cursor/Protocols and Xkbcommon versions are shown. Wayland EGL is option.
+
+```plaintext
+--
+--   GUI:                           Wayland
+--     Wayland:                     (Experimental) YES
+--       Wayland Client:            YES (ver 1.22.0)
+--       Wayland Cursor:            YES (ver 1.22.0)
+--       Wayland Protocols:         YES (ver 1.34)
+--       Xkbcommon:                 YES (ver 1.6.0)
+--       Wayland EGL(Option):       YES (ver 18.1.0)
+--     GTK+:                        NO
+--     VTK support:                 NO
+```
+
+Run `cmake --build` to build, and `sudo cmake --install` to install into your system.
+
+```bash
+cmake --build build4-main
+sudo cmake --install build4-main
+sudo ldconfig
+```
+
+Simple Application to try Wayland highgui-backend
+-------------------------------------------------
+Try this code, so you can see name of currentUIFrramework() and OpenCV logo window with Wayland highgui-backend.
+
+
+```bash
+// 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;
+}
+```
+
+Limitation/Known problem
+------------------------
+- cv::moveWindow() is not implementated. ( See. https://github.com/opencv/opencv/issues/25478 )

doc/tutorials/app/intelperc.markdown

@@ -4,6 +4,7 @@ Using Creative Senz3D and other Intel RealSense SDK compatible depth sensors {#t
 @tableofcontents
 
 @prev_tutorial{tutorial_orbbec_astra}
+@next_tutorial{tutorial_wayland_ubuntu}
 
 ![hardwares](images/realsense.jpg)
 

doc/tutorials/app/table_of_content_app.markdown

@@ -8,3 +8,4 @@ Application utils (highgui, imgcodecs, videoio modules) {#tutorial_table_of_cont
 -   @subpage tutorial_kinect_openni
 -   @subpage tutorial_orbbec_astra
 -   @subpage tutorial_intelperc
+-   @subpage tutorial_wayland_ubuntu

doc/tutorials/introduction/config_reference/config_reference.markdown

@@ -621,6 +621,7 @@ Following build options are utilized in `opencv_contrib` modules, as stated [pre
 `CMAKE_TOOLCHAIN_FILE`
 
 `WITH_CAROTENE`
+`WITH_KLEIDICV`
 `WITH_CPUFEATURES`
 `WITH_EIGEN`
 `WITH_DIRECTX`

doc/tutorials/introduction/env_reference/env_reference.markdown

@@ -46,10 +46,16 @@ MY_ENV_VARIABLE=true ./my_app
 
 ```.py
 import os
-os.environ["MY_ENV_VARIABLE"] = True
+os.environ["MY_ENV_VARIABLE"] = "True" # value must be a string
 import cv2 # variables set after this may not have effect
 ```
 
+@note This method may not work on all operating systems and/or Python distributions. For example, it works on Ubuntu Linux with system Python interpreter, but doesn't work on Windows 10 with the official Python package. It depends on the ability of a process to change its own environment (OpenCV uses `getenv` from C++ runtime to read variables).
+
+@note See also:
+- https://docs.python.org/3.12/library/os.html#os.environ
+- https://stackoverflow.com/questions/69199708/setenvironmentvariable-does-not-seem-to-set-values-that-can-be-retrieved-by-ge
+
 
 ## Types