Running application with user privillegions.

SGaist — Sat, 28 Mar 2026 10:11:30 GMT

@nicholas_ru said in Running application with user privillegions.: @SGaist said in Running application with user privillegions.: Just in case: KDE has Polkit-Qt On Github compile with Qt 5.x.How compile with Qt 6.x? Beside the comment from @JonB, if you could give more accurate information, links, etc. It would help us help you.

How could I rise to UDP speed ?

JonB — Fri, 10 Apr 2026 13:51:41 GMT

@Joe-von-Habsburg Ah ha! One of us should have mentioned this when you said about sender packet size :(

Icon for linux application

Joe von Habsburg — Wed, 21 May 2025 13:03:17 GMT

Thank you so much, It works. For that kind of things, must be so explanatory. Thanks everyone :)

Qt 19 kann kein Projekt anlegen

jsulm — Tue, 14 Apr 2026 14:47:51 GMT

@AndyS can you help to remove the account

Display an image in a c++ program

jsulm — Wed, 29 Apr 2026 18:24:45 GMT

@JYG61 See "Topics Tools" at the top

programmatically moving the scrollbar in a scrollarea

C_H_E_N — Fri, 17 Apr 2026 15:00:09 GMT

As far as I understand, manually setting minimum/maximum may cause unexpected result. See: https://github.com/qt/qtbase/blob/dev/src/widgets/widgets/qscrollarea.cpp#L191 The min/max values are most likely measured in pixels. Otherwise, I don't understand why QScrollArea does that by default vbar->setRange(0, v.height() - p.height()); So if you limit the maximum to 100, you are probably going to only see very limited part of your table, which may result in looking like "nothing happened" because <100 pixels is perhaps too unnoticeable. You may try unsetting min/max value and just try something like QScrollBar* scrollBar = ; scrollBar->setValue(int(scrollBar->maximum() * 0.1f)); And see if you can notice something. And another recommendation is that a minimal reproducing sample can really help here.

QQuickFramebufferObject::Renderer::render() not even being called

SGaist — Tue, 28 Apr 2026 08:07:24 GMT

Where are you trying to get these events in your project ?

Getting the size of the MainWindow

Axel Spoerl — Thu, 30 Apr 2026 20:29:28 GMT

@hskoglund Using a timer can be anything between a waste of time and vain hope. It depends on the operating system, how showMaximized(), showNormal() and the like are handled. QWidget::windowState() reflects what has been ordered to the window manager. The problem is that the widget's geometry can change twice. First time when showMaximized() has been processed and widget->windowState().testFlag(Qt::WindowMaximized) returns true. Second time, when the window manager has applied decorations (i.e. title bar and window handles). A good place to look for inspiration is tst_QWidget::showMaximized() and showFullScreen(). The QTRY_ macros generally process events until either the predicate is true or a timeout is hit. They're not available in applications, but you can write your own methods that work for your use case.

[Qt 6.12] Deprecation of QString in 6.12.0 and complete removal in 6.12.1.4.1

Liang Qi — Wed, 01 Apr 2026 15:14:26 GMT

Oh, a post on April 1st.

Deleting and recreating QApplication object

GreatJobQTbeHostileToEvenNewbies — Thu, 30 Apr 2026 13:47:45 GMT

@Kent-Dorfman Moles and trolls...Moles and trolls...LOL Seen your own DP lately? Great Projection, so very helpful to newbies this is surely helping Qt stay afloat. Oh whats this? https://news.ycombinator.com/item?id=28627022 “Engineers can't explain it, legal can't understand it", “What companies want is certainty… Qt lacks it”,"It’s not just cost — it’s fear of getting licensing wrong",,"Qt's corporate owners have been openly hostile to the community for a while" are common sayings in the community? I was even being well civil but now i shall and will be otherwise: can't even answer lack of basic devops fundamental industry flows in QT, or improve itself while worse companies like microsoft can. May the likes of Oracle and Qt and others with majority investors from banking sectors may drown in their yachts in random storms.. metaphorically. @Christian-Ehrlicher ban my soon to be autoscripted posts from my x many emails as x many times you want, truth will remain that Qt is abandonware without KDE and ugly frankenstein's monster with pinochio's nose thanks to yall bloodthirstynachtzikapitalists. You'r both getting traction at bilbili already. it will be fun :D Well i was able to rework my QT app to a better cross platform technology in just few hours and removed all Qt bs from my home now, also have I blocking my own account notifications coming from QT all ze bezt

QWidgetAction not visible

Joe von Habsburg — Sat, 20 Apr 2013 19:54:18 GMT

thanks for your reply and explain

2200% CPU Usage from processed camera feed implementation

OyvindNordbo — Wed, 29 Apr 2026 08:02:37 GMT

@Ronel_qtmaster @GrecKo Thank you both for the suggestions — I'll work through them and report back. Unfortunately I can't share much code as I initially said due to project confidentiality, but here's as much context as I can give (feel free to ask for more if there's any confusion): Architecture overview: The backend runs a ROS2 classification node using Ultralytics YOLOv8 + PyTorch. This is understandably CPU-heavy. My GUI class subscribes to a ROS topic that fires a signal each time the classification of one frame completes. A camera bridge class is connected to the GUI class and forwards frames to QML. The QML GUI itself runs as a dedicated ROS2 node, launched inside a QThread. Comparison with the old Widget-based GUI: The previous implementation used QPixmap inside a standard Qt Widgets GUI. It worked — the FPS dropped from ~30 to ~10 due to the ML overhead, but it was fully usable. My QML implementation is significantly worse: ~1 FPS with a ~20-second rendering delay, making camera control completely unusable. Since the backend is identical in both cases, the bottleneck must be in how I'm bridging frames from the ROS2 subscription into QML. Potential issue I'm investigating: I suspect the QML rendering pipeline is either blocking on frame delivery, accumulating a backlog of unprocessed frames, or doing unnecessary work on the UI thread — but I haven't pinpointed it yet. Could there be a potential fault in how I configure the main.cpp file? I've provided the core logic from my implementation below. int main( argc, *argv[]) { qputenv("QSG_RENDER_LOOP", "thread"); //tried to use basic, virtually no difference rclcpp::init(argc, argv); qRegisterMetaType("QImage") ..... QApplication app(argc, argv); ..... QNode qnode; if (!qnode.init()) return -1; ....//Initializing camera auto cameraProvider = new CameraBridge(); engine.rootContext()->setContextProperty("cameraBridge", cameraProvider) ...... engine.load(url); if (engine.rootObjects().isEmpty()) return -1; int result = app.exec(); rclcpp::shutdown(); qnode.wait(); return result; } @Ronel_qtmaster — I tried applying your suggestion to my paint function but didn't see an improvement. It's possible I'm not applying it at the right point in the pipeline, but I belive my implementation is correct. @GrecKo — I'll implement your approach and report back today or tomorrow. Fallback plan: If I can't resolve this in QML, I may try embedding the old QPixmap-based camera widget into my QML app using QQuickWidget or similar. I know mixing Widgets and QML is generally discouraged in that direction, but it may be the pragmatic solution here. Any experience or tips with that approach would be welcomed.

Qt Quick2

Z.Johnn — Mon, 27 Apr 2026 03:29:34 GMT

@Christian-Ehrlicher Thank you all for your support and assistance. Eventually, I discovered the solution. Originally, it was necessary to add the resource files in the "qt_add_executable" section of the CMakeList file, and set CMAKE_AUTORCC to ON. Although the images couldn't be seen in the QML Designer of Qt Creator, they were displayed perfectly on the Android emulator.

Setting border on widget is inconsistent

rida_zouga — Mon, 20 Apr 2026 17:41:20 GMT

@Chris-Kawa Thank you so much for all the help!

How are the Qt translation tools deriving these strings?

Yuri Habadakas — Thu, 14 May 2026 05:29:58 GMT

@Christian-Ehrlicher said in How are the Qt translation tools deriving these strings?: @Yuri-Habadakas said in How are the Qt translation tools deriving these strings?: But I am surprised that it's pulled a string for a totally new dialog which did not previously exist. Why - it's a simple string compare and helpful for the translators. Well, I guess because it has no idea whether it's still valid in the context of the new location (and neither do I). But then again, I suppose that's why it marks it with unfinished, and that flag gets used by the Qt-native translation tools? (We use a different translation tool, and some scripts that convert the .ts files, and I only recently discovered this behaviour, and that the unfinished business wasn't being passed on by the conversion script!...)

QtCreator 19.0.1 Total crash when copying source code

aha_1980 — Sat, 25 Apr 2026 08:47:43 GMT

@Andy314 and @Udo-Alt I tried to reproduce the problem, but could not reproduce this bug. Can one of you give exact instructions with sample code to reproduce this problem? Then it would be possible to create a fix. Regards

Building QT 6.11.0 for Win32 platform

Christian Ehrlicher — Wed, 29 Apr 2026 08:43:31 GMT

See https://doc.qt.io/qt-6/supported-platforms.html#windows https://doc.qt.io/qt-6.8/windows.html https://doc.qt.io/archives/qt-6.2/windows.html

Qt Creator, CMakePresets and conan - can't use own conan profile

SebastianM — Tue, 21 Apr 2026 08:39:52 GMT

Update Qt Creator conan mechanism In file c:\Qt\Tools\QtCreator_v20\share\qtcreator\cmake-helper\package-manager.cmake in line 115 (file(WRITE "${CMAKE_BINARY_DIR}/conan-dependencies/CMakeLists.txt" ") generates CMakeLists.txt with hardcoded default profile A little bit higher set(PROFILE_FILE "") if (CONAN_HOST_PROFILE OR CONAN_BUILD_PROFILE) if (CONAN_HOST_PROFILE) set(PROFILE_FILE "${PROFILE_FILE} -pr:h \"${CONAN_HOST_PROFILE}\"") endif() if (CONAN_BUILD_PROFILE) set(PROFILE_FILE "${PROFILE_FILE} -pr:b \"${CONAN_BUILD_PROFILE}\"") endif() else() set(PROFILE_FILE "-pr:a \"${CMAKE_BINARY_DIR}/conan-dependencies/conan_host_profile\"") endif() and substitute in line 134 (before adding above lines) from -pr \\"${CMAKE_BINARY_DIR}/conan-dependencies/conan_host_profile\\" to "${PROFILE_FILE}".

Weird behaviour with Qml (transparent background)

J.Hilk — Mon, 20 Apr 2026 14:17:51 GMT

@uncore the actual problem is a false assumption. The black you see is not the transparent background after resize. It's just not rendered. I don't know if you can actually get a normal ApplicationWindow with only a transparent background. The Only way I know is via the QtFramelessWindowHint: [image: af646d06-9229-4099-8abb-975f44722759.png] but that comes with missing menu bar and stuff

New error building with MS Visual Studio

Ipse — Wed, 13 May 2026 16:43:38 GMT

You can also define QT_NO_DEPRECATED_WARNINGS. Don't know is it better approach or worth.

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