Core, Highgui: OpenGL wrappers & window free-callback API #29485
This PR is a continuation of the work started in [20371](https://github.com/opencv/opencv/pull/20371)
### Pull Request Readiness Checklist
See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request
- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [x] There is a reference to the original bug report and related work
- [x] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
Patch to opencv_extra has the same branch name.
- [x] The feature is well documented and sample code can be built with the project CMake
CI (Ubuntu ARM64 x2) showed the Python test suite aborting the whole
process with exit code 134: on a Qt-enabled build, namedWindow() tried
the "xcb" platform plugin, found no display (the Python test step,
unlike the C++ gtest step, does not run under xvfb-run), and Qt
aborted the process instead of raising a catchable exception -- so the
existing try/except around namedWindow never got a chance to run.
Fix: set QT_QPA_PLATFORM=offscreen (only if not already set) before
any GUI call. "offscreen" is the platform plugin Qt ships specifically
for headless/CI use, and is listed as available in the failing CI
job's own log output.
Verified locally: built opencv_python3 with WITH_QT=ON (real Qt6, not
the WITH_QT=OFF build used in the initial verification), and confirmed
that in a clean environment (no DISPLAY, no QT_QPA_PLATFORM preset),
namedWindow + saveWindowParameters + loadWindowParameters all succeed
with this fix, where they would previously depend on a native display
backend being reachable.
Both functions persist/restore a window's size, position, flags,
trackbar values, and zoom/pan state (Qt highgui backend only), take
only a plain String argument, and were already fully documented -- but
were declared CV_EXPORTS instead of CV_EXPORTS_W, so they were
unreachable from Python.
Sibling Qt-only functions in the same header (displayOverlay,
displayStatusBar) already follow the CV_EXPORTS_W + runtime
"not implemented without Qt" convention this change follows.
Adds a Python test that exercises namedWindow + save/loadWindowParameters
and gracefully skips when no GUI backend or no Qt support is present,
consistent with how other environment-dependent tests in this suite
(e.g. CUDA) skip rather than fail.
Verified locally: built opencv_python3 from this branch (WITH_QT=OFF)
and confirmed cv2.saveWindowParameters / cv2.loadWindowParameters are
present on the built module and correctly raise the expected
"compiled without QT support" error, proving the binding reaches the
C++ layer end-to-end.
Avoid lossy Latin-1 conversions when creating/looking up Qt HighGUI windows and convert C-string entry points to UTF-8 explicitly. This fixes non-ASCII title handling paths that could lead to mismatched window lookup and silent display failures.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Replace System.exit(-1) with exceptions in HighGui.java (#28696) #28699
## Summary
Library code should never call System.exit() as it kills the entire JVM. Replaced all 3 instances with appropriate exceptions.
Closes#28696
## Changes
- `imshow()` with empty image: `System.exit(-1)` -> `throw new IllegalArgumentException("Image is empty")`
- `waitKey()` with no windows: `System.exit(-1)` -> `throw new IllegalStateException("No windows created. Call imshow() first")`
- `waitKey()` with null window image: `System.exit(-1)` -> `throw new IllegalStateException("No image set for window: ... Call imshow() first")`
- `InterruptedException` catch: `printStackTrace()` -> `Thread.currentThread().interrupt()`
Respect QApplication::quitOnLastWindowClosed() before calling qApp->quit().
This prevents OpenCV from unintentionally terminating externally managed
Qt applications when the last HighGUI window is closed.
Fixes#28291
Use `link_libraries` instead of `add_defintions` to link against Qt 6.9
and newer to avoid un-expanded generator expressions from Qt cmake files
being appended to linker flags when building the HighGUI module.
The actual bug is likely in how Qt cmake files end up with these
un-expanded generator expressions in the first place — see discussion in
https://bugreports.qt.io/browse/QTBUG-134774 — but the recommended way
to link against the library is to use `link_libraries` anyway, so this
fix should do the trick.
Fixes issue #27223.
Close https://github.com/opencv/opencv/issues/27413
### Pull Request Readiness Checklist
See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request
- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [x] There is a reference to the original bug report and related work
- [ ] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
Patch to opencv_extra has the same branch name.
- [ ] The feature is well documented and sample code can be built with the project CMake
Looks like UWP builds were broken on 5.x:
```
C:\GHA-OCV-6\_work\opencv\opencv\opencv\modules\videoio\src\cap_winrt_capture.hpp(65,33): error C3646: 'size': unknown override specifier (compiling source file C:\GHA-OCV-6\_work\opencv\opencv\opencv\modules\videoio\src\cap_winrt_capture.cpp) [C:\GHA-OCV-6\_work\opencv\opencv\build\modules\videoio\opencv_videoio.vcxproj]
C:\GHA-OCV-6\_work\opencv\opencv\opencv\modules\videoio\src\cap_winrt_capture.hpp(65,37): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int (compiling source file C:\GHA-OCV-6\_work\opencv\opencv\opencv\modules\videoio\src\cap_winrt_capture.cpp) [C:\GHA-OCV-6\_work\opencv\opencv\build\modules\videoio\opencv_videoio.vcxproj]
C:\GHA-OCV-6\_work\opencv\opencv\opencv\modules\videoio\src\cap_winrt_capture.hpp(65,33): error C3646: 'size': unknown override specifier (compiling source file C:\GHA-OCV-6\_work\opencv\opencv\opencv\modules\videoio\src\videoio_registry.cpp) [C:\GHA-OCV-6\_work\opencv\opencv\build\modules\videoio\opencv_videoio.vcxproj]
C:\GHA-OCV-6\_work\opencv\opencv\opencv\modules\videoio\src\cap_winrt_capture.hpp(65,37): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int (compiling source file C:\GHA-OCV-6\_work\opencv\opencv\opencv\modules\videoio\src\videoio_registry.cpp) [C:\GHA-OCV-6\_work\opencv\opencv\build\modules\videoio\opencv_videoio.vcxproj]
C:\GHA-OCV-6\_work\opencv\opencv\opencv\modules\videoio\src\cap_winrt_capture.hpp(65,33): error C3646: 'size': unknown override specifier (compiling source file C:\GHA-OCV-6\_work\opencv\opencv\opencv\modules\videoio\src\cap_winrt_bridge.cpp) [C:\GHA-OCV-6\_work\opencv\opencv\build\modules\videoio\opencv_videoio.vcxproj]
C:\GHA-OCV-6\_work\opencv\opencv\opencv\modules\videoio\src\cap_winrt_capture.hpp(65,37): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int (compiling source file C:\GHA-OCV-6\_work\opencv\opencv\opencv\modules\videoio\src\cap_winrt_bridge.cpp) [C:\GHA-OCV-6\_work\opencv\opencv\build\modules\videoio\opencv_videoio.vcxproj]
C:\Program Files (x86)\Windows Kits\10\bin\10.0.19041.0\XamlCompiler\Microsoft.Windows.UI.Xaml.Common.targets(486,5): error MSB4181: The "CompileXaml" task returned false but did not log an error. [C:\GHA-OCV-6\_work\opencv\opencv\build\modules\videoio\opencv_videoio.vcxproj]
```
Notes:
- Pipeline passes even though there are errors in the build
- I decided to remove _highgui_ WinRT backend, because it uses C-API which is has been removed in 5.x. I believe nobody uses it anyway.
- Change in anneal library is caused by the issue in WinAPI header - it does not declare two functions for UWP, even though documentation states compatibility. See also https://github.com/openssl/openssl/pull/18311https://learn.microsoft.com/en-us/windows/win32/api/memoryapi/nf-memoryapi-virtuallock
> Minimum supported client Windows XP [desktop apps | UWP apps]
> Minimum supported server Windows Server 2003 [desktop apps | UWP apps]
Notify the main GUI thread upon receiving a close event instead of when
the windows is destroyed. Additionally there was a logic error in in
GuiReceiver::isLastWindow() that is corrected.
Fixes#6479 and #20822
displayOverlay doesn't disappear after timeout #27082Fixes#26555
### Expected Behaviour
An overlay should be displayed atop an image and then disappear after `delayms` has timed out, but it doesn't. Also, `displayStatusBar` doesn't appear to set any text on the window.
### Actual Behaviour
The overlay appears but doesn't disappear unless a mouse move event happens on the image.
### Changes
- Fixed the issue with `displayOverlay` not disappearing after the timeout.
### Checklist
- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV.
- [x] The PR is proposed to the proper branch.
- [x] There is a reference to the original bug report and related work.
- [ ] There is accuracy test, performance test, and test data in the opencv_extra repository, if applicable.
- [ ] The feature is well documented, and sample code can be built with the project CMake.
Update window_cocoa.mm #26662
### Pull Request Readiness Checklist
See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request
- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [x] There is a reference to the original bug report and related work
- [x] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
Patch to opencv_extra has the same branch name.
- [x] The feature is well documented and sample code can be built with the project CMake
- [x ] Added reference to the original bug report (#26661).
- [x]Updated the code as per the reviewer's suggestion to use a ternary operator.
- [x] Verified that the feature is properly documented and can be built with CMake.
Performance tests for image encoders and decoders and code cleanup #26872
### Pull Request Readiness Checklist
See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request
- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [ ] There is a reference to the original bug report and related work
- [ ] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
Patch to opencv_extra has the same branch name.
- [ ] The feature is well documented and sample code can be built with the project CMake
Support C++20 standard #26590
Close https://github.com/opencv/opencv/issues/26589
Related https://github.com/opencv/opencv_contrib/pull/3842
Related: https://github.com/opencv/opencv/issues/20269
- do not arithmetic enums and ( different enums or floating numeric)
- remove unused variable
### Pull Request Readiness Checklist
See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request
- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [x] There is a reference to the original bug report and related work
- [x] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
Patch to opencv_extra has the same branch name.
- [x] The feature is well documented and sample code can be built with the project CMake
Updated trackbar callback function and improved documentation #26524
This Fixes#26467
Description:
This pull request improve the OpenCV documentation regarding the Trackbar functionality. The current documentation does not provide clear guidance on certain aspects, such as handling the value pointer deprecation and utilizing callback arguments in C. This update addresses those gaps and provides an updated example for better clarity.
Changes:
Updated Documentation:
Clarified the usage of the value pointer and explained how to pass an initial value, since the value pointer is deprecated.
Added more detailed explanations about callback arguments in C, ensuring that users understand how to access and use them in Trackbar callbacks.
Added a note on how to properly handle initial value passing without relying on the deprecated value pointer.
Updated Tutorial Example:
Renamed and used callback function parameters to make them more understandable.
Included a demonstration on how to utilize userdata in the callback function.
Additional Notes:
Removed reliance on the value pointer for updating trackbar values. Users are now encouraged to use other mechanisms as per the current implementation to avoid the runtime warning.
### Pull Request Readiness Checklist
See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request
- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [x] There is a reference to the original bug report and related work
- [x] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
Patch to opencv_extra has the same branch name.
- [] The feature is well documented and sample code can be built with the project CMake
Missing include directories needed for wayland-util and xkbcommon #26563
See: #26561
### Pull Request Readiness Checklist
See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request
- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [x] There is a reference to the original bug report and related work
- [ ] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
Patch to opencv_extra has the same branch name.
- [ ] The feature is well documented and sample code can be built with the project CMake
❗ Potential conflicts with #25958
C-API cleanup: highgui, videoio #26025❗ Merge with: opencv/opencv_contrib#3780
This PR removes usage of C-API from highgui and videoio modules. Only source code is affected, tests were not using obsolete API.
It should be possible to backport these changes to 4.x branch preserving removed public headers and source files (`*_c.h` and `*_c.cpp`).
#### Checklist
I tried to verify as many backends as possible, though these checks were not as thorough as I'd like them to be. Below is the checklist covering all modified backends with their statuses.
> 🔹 - small changes
> 🟢 - consider working
> ⚪ - considered untested
##### highgui
Pass | Backend | Local check | CI check
-----|---------|-------------|---------
🟢 | GTK2 | build + test, plugin build | build + test ❔🟢 | GTK3 | build + test, plugin build | build + test
🟢 | QT | build + test, plugin build |
⚪ | Wayland 🔹 | |
🟢 | WIN32 🔹 | | build + test
🟢 | Cocoa 🔹 | | build + test
⚪ | WinRT | |
##### videoio
Pass | Backend | Local check | CI check
-----|---------|-------------|---------
🟢 | Android Camera/MediaNDK 🔹 | | build
🟢 | Aravis | build |
🟢 | AVFoundation OSX | | build + test
⚪ | AVFoundation iOS | | build
🟢 | DC1394 | build |
🟢 | DShow 🔹 | | build
🟢 | FFMpeg | build, plugin build | build + test
🟢 | GPhoto 🔹 | build |
🟢 | GStreamer | build, plugin build | build + test
🟢 | Images | build | build + test
🟢 | MSMF 🔹 | | build + test
🟢 | OpenNI | build |
🟢 | PVAPI | build |
🟢 | V4L | build + test | build
🟢 | XIMEA | build |
🟢 | XINE 🔹 | build |
#### Notes
- local linux build checks performed using [this framework](https://github.com/mshabunin/opencv-videoio-build-check)
- minor extra changes made in both `cap_avfoundation*.mm` to make them slightly more synchronized - it would be better to combine them into a single one in the future
- configurations with plugins have been build but not tested
- **moved unrelated changes to separate PRs** ~two issues have been fixed in separate commits:~
- ~imgproc: missing `cv::hal::` color conversion functions has been used in MediaSDK backend~
- ~videoio/V4L: wrong color conversion mode caused bad colors for NV12 camera input format (RGB instead of BGR)~
It would be nice to check following functionality manually:
- [ ] OSX: camera input
- [ ] iOS: camera and file input
- [ ] WinRT: build, some testing
- [x] Linux/Wayland: build
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