trialuser02 / qt6ct Goto Github PK

On both Debian & Arch, font changes made in qt6ct gui are not saved on exit.
Restarting qt6ct, the original font definition is still there.
This relates to .config/qt6ct/qt6ct.conf not fonts.conf

Maybe a recent regression (0.7?) as I'm sure this used to work fine

Let me make it brief, we have a custom distro (TROMjaro) based on XFCE (gtk) and we use QT5CT and QT6CT to sync the themes and fonts and all that. All works great, except for the font. So we look for a way to sync the font as well. The main way for qt6/5ct is via the config file in the .config folder. But you guys are storing the font as https://github.com/desktop-app/qt5ct/blob/9f60cd2352a4dcc55c8ca267f29bd8fff5c6a659/src/qt5ct/fontspage.cpp#L61 - you convert it via C++ I think into a format that is hard to read and convert into.

First, I am wondering why did you choose that and are you willing to store the font in a readable way? Like: Ubuntu Condensed, 13 for instance. We have scripts that check the desktop theme and icon set, and replace them in the qt5/6ct config file, but we cannot do the same for the font since the qt5/6ct config file only accepts that converted format.

Second, is there a way via the command line to change the font for QT? This we can implement into the script perhaps.

Thank you in advance!

I mean, what happens in colors/*.conf is not clear at all. I searched everywhere and didn't find a single note on how to select the colors for your own theme. Like, which value stands for what? Why are they repeating themselves? Why there are so much values?

Segmentation fault happen after upgrade some qt6 packages on qt6 base gui application, like cmake-gui and qmmp.

by removing qt6ct it solve the problem but lose the configuration (theme, font, etc).

problem is:

• lrelease is part of the qttools module
• qtpaths is part of the qtbase module

so, on nixos, these have different prefixes

fixed by using the commented code blocks

--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -24,14 +24,14 @@
 
 find_package(Qt6 COMPONENTS BuildInternals Widgets Concurrent LinguistTools REQUIRED)
 
-#get_target_property(QT_QTPATHS_EXECUTABLE Qt6::qtpaths IMPORTED_LOCATION)
+get_target_property(QT_QTPATHS_EXECUTABLE Qt6::qtpaths IMPORTED_LOCATION)
 get_target_property(QT_LRELEASE_EXECUTABLE Qt6::lrelease IMPORTED_LOCATION)
 
-#if(QT_QTPATHS_EXECUTABLE)
-#    message(STATUS "Found qtpaths executable: " ${QT_QTPATHS_EXECUTABLE})
-#else()
-#    message(FATAL_ERROR "Could NOT find qtpaths executable")
-#endif()
+if(QT_QTPATHS_EXECUTABLE)
+    message(STATUS "Found qtpaths executable: " ${QT_QTPATHS_EXECUTABLE})
+else()
+    message(FATAL_ERROR "Could NOT find qtpaths executable")
+endif()
 
 if(QT_LRELEASE_EXECUTABLE)
     message(STATUS "Found lrelease executable: " ${QT_LRELEASE_EXECUTABLE})
@@ -39,15 +39,6 @@
     message(FATAL_ERROR "Could NOT find lrelease executable")
 endif()
 
-get_filename_component(QT_QTPATHS_EXECUTABLE ${QT_LRELEASE_EXECUTABLE} DIRECTORY)
-set(QT_QTPATHS_EXECUTABLE ${QT_QTPATHS_EXECUTABLE}/qtpaths)
-
-if(EXISTS ${QT_QTPATHS_EXECUTABLE})
-    message(STATUS "Found qtpaths executable: " ${QT_QTPATHS_EXECUTABLE})
-else()
-    message(FATAL_ERROR "Could NOT find qtpaths executable")
-endif()
-
 #execute_process(COMMAND ${QT_QTPATHS_EXECUTABLE} -query QT_INSTALL_PLUGINS OUTPUT_VARIABLE PLUGINDIR OUTPUT_STRIP_TRAILING_WHITESPACE)
 execute_process(COMMAND ${QT_QTPATHS_EXECUTABLE} --plugin-dir OUTPUT_VARIABLE PLUGINDIR OUTPUT_STRIP_TRAILING_WHITESPACE)
 message(STATUS "Plugin path: " ${PLUGINDIR})

fixed by using the commented code blocks

is there a good reason this code is commented?
maybe use the current code as fallback?

Is wayland supported?
How can I provide more details? Find the coredump details?

qt.qpa.plugin: Could not find the Qt platform plugin "wayland" in ""
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: eglfs, offscreen, vnc, xcb, linuxfb, vkkhrdisplay, minimalegl, minimal.

zsh: IOT instruction (core dumped)  qt6ct

This might be out of scope as this uses a custom version of qt5ct but if qt5ct-kde compatability can be added, it would be great help.

system

• Theme (qt5ct)
  • https://aur.archlinux.org/packages/lightly-boehs-git
• colorscheme
  • https://github.com/catppuccin/kde/releases/download/v0.2.4/Mocha-color-schemes.tar.gz
• qt5ct
  • https://aur.archlinux.org/packages/qt5ct-kde
• qt6ct
  • 4bf8dee

coredump

Aug 25 19:28:21 ls-2100 systemd-coredump[146846]: [🡕] Process 146784 (qt6ct) of user 1000 dumped core.
                                                  
                                                  Stack trace of thread 146784:
                                                  #0  0x00007f5c6f060fec n/a (libc.so.6 + 0x60fec)
                                                  #1  0x00007f5c6f055d73 __isoc23_sscanf (libc.so.6 + 0x55d73)
                                                  #2  0x00007f5c6f0caf2f n/a (libc.so.6 + 0xcaf2f)
                                                  #3  0x00007f5c6f0cb482 n/a (libc.so.6 + 0xcb482)
                                                  #4  0x00007f5c6f0ccdf1 n/a (libc.so.6 + 0xccdf1)
                                                  #5  0x00007f5c6f0cb91c n/a (libc.so.6 + 0xcb91c)
                                                  #6  0x00007f5c6fa3dbed n/a (libQt6Core.so.6 + 0x23dbed)
                                                  #7  0x00007f5c6fa33a78 n/a (libQt6Core.so.6 + 0x233a78)
                                                  #8  0x00007f5c6fa35347 _ZN9QDateTime18setMSecsSinceEpochEx (libQt6Core.so.6 + 0x235347)
                                                  #9  0x00007f5c6fa3672b _ZN9QDateTime19fromMSecsSinceEpochExRK9QTimeZone (libQt6Core.so.6 + 0x23672b)
                                                  #10 0x00007f5c6fa3681e _ZNK9QDateTime10toTimeZoneERK9QTimeZone (libQt6Core.so.6 + 0x23681e)
                                                  #11 0x00007f5c6fa37740 _ZNK9QDateTime11toLocalTimeEv (libQt6Core.so.6 + 0x237740)
                                                  #12 0x00007f5c6fb773ee n/a (libQt6Core.so.6 + 0x3773ee)
                                                  #13 0x00007f5c6fad87d1 n/a (libQt6Core.so.6 + 0x2d87d1)
                                                  #14 0x00007f5c6fad8d4d n/a (libQt6Core.so.6 + 0x2d8d4d)
                                                  #15 0x00007f5c6fada527 _ZN9QSettingsC1ERK7QStringNS_6FormatEP7QObject (libQt6Core.so.6 + 0x2da527)
                                                  #16 0x00007f5c6bf5e6a1 n/a (libqt6ct-style.so + 0x36a1)
                                                  #17 0x00007f5c6bf5ecf7 n/a (libqt6ct-style.so + 0x3cf7)
                                                  #18 0x00007f5c6bf5e2bc n/a (libqt6ct-style.so + 0x32bc)
                                                  #19 0x00007f5c70a017ed _ZN13QStyleFactory6createERK7QString (libQt6Widgets.so.6 + 0x2017ed)
                                                  #20 0x00007f5c6bf5e9aa n/a (libqt6ct-style.so + 0x39aa)
                                                  #21 0x00007f5c6bf5ecf7 n/a (libqt6ct-style.so + 0x3cf7)
                                                  #22 0x00007f5c6bf5e2bc n/a (libqt6ct-style.so + 0x32bc)
                                                  #23 0x00007f5c70a017ed _ZN13QStyleFactory6createERK7QString (libQt6Widgets.so.6 + 0x2017ed)
                                                  #24 0x00007f5c6bf5e9aa n/a (libqt6ct-style.so + 0x39aa)
                                                  #25 0x00007f5c6bf5ecf7 n/a (libqt6ct-style.so + 0x3cf7)
                                                  #26 0x00007f5c6bf5e2bc n/a (libqt6ct-style.so + 0x32bc)
                                                  #27 0x00007f5c70a017ed _ZN13QStyleFactory6createERK7QString (libQt6Widgets.so.6 + 0x2017ed)
                                                  #28 0x00007f5c6bf5e9aa n/a (libqt6ct-style.so + 0x39aa)
                                                  #29 0x00007f5c6bf5ecf7 n/a (libqt6ct-style.so + 0x3cf7)
                                                  #30 0x00007f5c6bf5e2bc n/a (libqt6ct-style.so + 0x32bc)
                                                  #31 0x00007f5c70a017ed _ZN13QStyleFactory6createERK7QString (libQt6Widgets.so.6 + 0x2017ed)
                                                  #32 0x00007f5c6bf5e9aa n/a (libqt6ct-style.so + 0x39aa)
                                                  #33 0x00007f5c6bf5ecf7 n/a (libqt6ct-style.so + 0x3cf7)
                                                  #34 0x00007f5c6bf5e2bc n/a (libqt6ct-style.so + 0x32bc)
                                                  #35 0x00007f5c70a017ed _ZN13QStyleFactory6createERK7QString (libQt6Widgets.so.6 + 0x2017ed)
                                                  #36 0x00007f5c6bf5e9aa n/a (libqt6ct-style.so + 0x39aa)
                                                  #37 0x00007f5c6bf5ecf7 n/a (libqt6ct-style.so + 0x3cf7)
                                                  #38 0x00007f5c6bf5e2bc n/a (libqt6ct-style.so + 0x32bc)
                                                  #39 0x00007f5c70a017ed _ZN13QStyleFactory6createERK7QString (libQt6Widgets.so.6 + 0x2017ed)
                                                  #40 0x00007f5c6bf5e9aa n/a (libqt6ct-style.so + 0x39aa)
                                                  #41 0x00007f5c6bf5ecf7 n/a (libqt6ct-style.so + 0x3cf7)
                                                  #42 0x00007f5c6bf5e2bc n/a (libqt6ct-style.so + 0x32bc)
                                                  #43 0x00007f5c70a017ed _ZN13QStyleFactory6createERK7QString (libQt6Widgets.so.6 + 0x2017ed)
                                                  #44 0x00007f5c6bf5e9aa n/a (libqt6ct-style.so + 0x39aa)
                                                  #45 0x00007f5c6bf5ecf7 n/a (libqt6ct-style.so + 0x3cf7)
                                                  #46 0x00007f5c6bf5e2bc n/a (libqt6ct-style.so + 0x32bc)
                                                  #47 0x00007f5c70a017ed _ZN13QStyleFactory6createERK7QString (libQt6Widgets.so.6 + 0x2017ed)
                                                  #48 0x00007f5c6bf5e9aa n/a (libqt6ct-style.so + 0x39aa)
                                                  #49 0x00007f5c6bf5ecf7 n/a (libqt6ct-style.so + 0x3cf7)
                                                  #50 0x00007f5c6bf5e2bc n/a (libqt6ct-style.so + 0x32bc)
                                                  #51 0x00007f5c70a017ed _ZN13QStyleFactory6createERK7QString (libQt6Widgets.so.6 + 0x2017ed)
                                                  #52 0x00007f5c6bf5e9aa n/a (libqt6ct-style.so + 0x39aa)
                                                  #53 0x00007f5c6bf5ecf7 n/a (libqt6ct-style.so + 0x3cf7)
                                                  #54 0x00007f5c6bf5e2bc n/a (libqt6ct-style.so + 0x32bc)
                                                  #55 0x00007f5c70a017ed _ZN13QStyleFactory6createERK7QString (libQt6Widgets.so.6 + 0x2017ed)
                                                  #56 0x00007f5c6bf5e9aa n/a (libqt6ct-style.so + 0x39aa)
                                                  #57 0x00007f5c6bf5ecf7 n/a (libqt6ct-style.so + 0x3cf7)
                                                  #58 0x00007f5c6bf5e2bc n/a (libqt6ct-style.so + 0x32bc)
                                                  #59 0x00007f5c70a017ed _ZN13QStyleFactory6createERK7QString (libQt6Widgets.so.6 + 0x2017ed)
                                                  #60 0x00007f5c6bf5e9aa n/a (libqt6ct-style.so + 0x39aa)
                                                  #61 0x00007f5c6bf5ecf7 n/a (libqt6ct-style.so + 0x3cf7)
                                                  #62 0x00007f5c6bf5e2bc n/a (libqt6ct-style.so + 0x32bc)
                                                  #63 0x00007f5c70a017ed _ZN13QStyleFactory6createERK7QString (libQt6Widgets.so.6 + 0x2017ed)
                                                  
                                                  Stack trace of thread 146785:
                                                  #0  0x00007f5c6f10359f __poll (libc.so.6 + 0x10359f)
                                                  #1  0x00007f5c6f76cc2f n/a (libglib-2.0.so.0 + 0xb7c2f)
                                                  #2  0x00007f5c6f70d0e2 g_main_context_iteration (libglib-2.0.so.0 + 0x580e2)
                                                  #3  0x00007f5c6fb32794 _ZN20QEventDispatcherGlib13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (libQt6Core.so.6 + 0x332794)
                                                  #4  0x00007f5c6f945623 _ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE (libQt6Core.so.6 + 0x145623)
                                                  #5  0x00007f5c6fa2d14f _ZN7QThread4execEv (libQt6Core.so.6 + 0x22d14f)
                                                  #6  0x00007f5c6f378aef n/a (libQt6DBus.so.6 + 0x2eaef)
                                                  #7  0x00007f5c6fa73352 n/a (libQt6Core.so.6 + 0x273352)
                                                  #8  0x00007f5c6f08c9eb n/a (libc.so.6 + 0x8c9eb)
                                                  #9  0x00007f5c6f110dfc n/a (libc.so.6 + 0x110dfc)
                                                  
                                                  Stack trace of thread 146789:
                                                  #0  0x00007f5c6f0894ae n/a (libc.so.6 + 0x894ae)
                                                  #1  0x00007f5c6f08c055 pthread_cond_timedwait (libc.so.6 + 0x8c055)
                                                  #2  0x00007f5c6fa76e38 _ZN14QWaitCondition4waitEP6QMutex14QDeadlineTimer (libQt6Core.so.6 + 0x276e38)
                                                  #3  0x00007f5c6fa71cf6 n/a (libQt6Core.so.6 + 0x271cf6)
                                                  #4  0x00007f5c6fa73352 n/a (libQt6Core.so.6 + 0x273352)
                                                  #5  0x00007f5c6f08c9eb n/a (libc.so.6 + 0x8c9eb)
                                                  #6  0x00007f5c6f110dfc n/a (libc.so.6 + 0x110dfc)
                                                  
                                                  Stack trace of thread 146790:
                                                  #0  0x00007f5c6f0894ae n/a (libc.so.6 + 0x894ae)
                                                  #1  0x00007f5c6f08c055 pthread_cond_timedwait (libc.so.6 + 0x8c055)
                                                  #2  0x00007f5c6fa76e38 _ZN14QWaitCondition4waitEP6QMutex14QDeadlineTimer (libQt6Core.so.6 + 0x276e38)
                                                  #3  0x00007f5c6fa71cf6 n/a (libQt6Core.so.6 + 0x271cf6)
                                                  #4  0x00007f5c6fa73352 n/a (libQt6Core.so.6 + 0x273352)
                                                  #5  0x00007f5c6f08c9eb n/a (libc.so.6 + 0x8c9eb)
                                                  #6  0x00007f5c6f110dfc n/a (libc.so.6 + 0x110dfc)
                                                  
                                                  Stack trace of thread 146795:
                                                  #0  0x00007f5c6f0894ae n/a (libc.so.6 + 0x894ae)
                                                  #1  0x00007f5c6f08c055 pthread_cond_timedwait (libc.so.6 + 0x8c055)
                                                  #2  0x00007f5c6fa76e38 _ZN14QWaitCondition4waitEP6QMutex14QDeadlineTimer (libQt6Core.so.6 + 0x276e38)
                                                  #3  0x00007f5c6fa71cf6 n/a (libQt6Core.so.6 + 0x271cf6)
                                                  #4  0x00007f5c6fa73352 n/a (libQt6Core.so.6 + 0x273352)
                                                  #5  0x00007f5c6f08c9eb n/a (libc.so.6 + 0x8c9eb)
                                                  #6  0x00007f5c6f110dfc n/a (libc.so.6 + 0x110dfc)
                                                  
                                                  Stack trace of thread 146791:
                                                  #0  0x00007f5c6f0894ae n/a (libc.so.6 + 0x894ae)
                                                  #1  0x00007f5c6f08c055 pthread_cond_timedwait (libc.so.6 + 0x8c055)
                                                  #2  0x00007f5c6fa76e38 _ZN14QWaitCondition4waitEP6QMutex14QDeadlineTimer (libQt6Core.so.6 + 0x276e38)
                                                  #3  0x00007f5c6fa71cf6 n/a (libQt6Core.so.6 + 0x271cf6)
                                                  #4  0x00007f5c6fa73352 n/a (libQt6Core.so.6 + 0x273352)
                                                  #5  0x00007f5c6f08c9eb n/a (libc.so.6 + 0x8c9eb)
                                                  #6  0x00007f5c6f110dfc n/a (libc.so.6 + 0x110dfc)
                                                  
                                                  Stack trace of thread 146786:
                                                  #0  0x00007f5c6f10359f __poll (libc.so.6 + 0x10359f)
                                                  #1  0x00007f5c6bb84a68 n/a (libQt6WaylandClient.so.6 + 0x68a68)
                                                  #2  0x00007f5c6fa73352 n/a (libQt6Core.so.6 + 0x273352)
                                                  #3  0x00007f5c6f08c9eb n/a (libc.so.6 + 0x8c9eb)
                                                  #4  0x00007f5c6f110dfc n/a (libc.so.6 + 0x110dfc)
                                                  
                                                  Stack trace of thread 146793:
                                                  #0  0x00007f5c6f0894ae n/a (libc.so.6 + 0x894ae)
                                                  #1  0x00007f5c6f08c055 pthread_cond_timedwait (libc.so.6 + 0x8c055)
                                                  #2  0x00007f5c6fa76e38 _ZN14QWaitCondition4waitEP6QMutex14QDeadlineTimer (libQt6Core.so.6 + 0x276e38)
                                                  #3  0x00007f5c6fa71cf6 n/a (libQt6Core.so.6 + 0x271cf6)
                                                  #4  0x00007f5c6fa73352 n/a (libQt6Core.so.6 + 0x273352)
                                                  #5  0x00007f5c6f08c9eb n/a (libc.so.6 + 0x8c9eb)
                                                  #6  0x00007f5c6f110dfc n/a (libc.so.6 + 0x110dfc)
                                                  
                                                  Stack trace of thread 146792:
                                                  #0  0x00007f5c6f0894ae n/a (libc.so.6 + 0x894ae)
                                                  #1  0x00007f5c6f08c055 pthread_cond_timedwait (libc.so.6 + 0x8c055)
                                                  #2  0x00007f5c6fa76e38 _ZN14QWaitCondition4waitEP6QMutex14QDeadlineTimer (libQt6Core.so.6 + 0x276e38)
                                                  #3  0x00007f5c6fa71cf6 n/a (libQt6Core.so.6 + 0x271cf6)
                                                  #4  0x00007f5c6fa73352 n/a (libQt6Core.so.6 + 0x273352)
                                                  #5  0x00007f5c6f08c9eb n/a (libc.so.6 + 0x8c9eb)
                                                  #6  0x00007f5c6f110dfc n/a (libc.so.6 + 0x110dfc)
                                                  
                                                  Stack trace of thread 146799:
                                                  #0  0x00007f5c6f0894ae n/a (libc.so.6 + 0x894ae)
                                                  #1  0x00007f5c6f08c055 pthread_cond_timedwait (libc.so.6 + 0x8c055)
                                                  #2  0x00007f5c6fa76e38 _ZN14QWaitCondition4waitEP6QMutex14QDeadlineTimer (libQt6Core.so.6 + 0x276e38)
                                                  #3  0x00007f5c6fa71cf6 n/a (libQt6Core.so.6 + 0x271cf6)
                                                  #4  0x00007f5c6fa73352 n/a (libQt6Core.so.6 + 0x273352)
                                                  #5  0x00007f5c6f08c9eb n/a (libc.so.6 + 0x8c9eb)
                                                  #6  0x00007f5c6f110dfc n/a (libc.so.6 + 0x110dfc)
                                                  
                                                  Stack trace of thread 146794:
                                                  #0  0x00007f5c6f0894ae n/a (libc.so.6 + 0x894ae)
                                                  #1  0x00007f5c6f08c055 pthread_cond_timedwait (libc.so.6 + 0x8c055)
                                                  #2  0x00007f5c6fa76e38 _ZN14QWaitCondition4waitEP6QMutex14QDeadlineTimer (libQt6Core.so.6 + 0x276e38)
                                                  #3  0x00007f5c6fa71cf6 n/a (libQt6Core.so.6 + 0x271cf6)
                                                  #4  0x00007f5c6fa73352 n/a (libQt6Core.so.6 + 0x273352)
                                                  #5  0x00007f5c6f08c9eb n/a (libc.so.6 + 0x8c9eb)
                                                  #6  0x00007f5c6f110dfc n/a (libc.so.6 + 0x110dfc)
                                                  
                                                  Stack trace of thread 146787:
                                                  #0  0x00007f5c6f10359f __poll (libc.so.6 + 0x10359f)
                                                  #1  0x00007f5c6bb84a68 n/a (libQt6WaylandClient.so.6 + 0x68a68)
                                                  #2  0x00007f5c6fa73352 n/a (libQt6Core.so.6 + 0x273352)
                                                  #3  0x00007f5c6f08c9eb n/a (libc.so.6 + 0x8c9eb)
                                                  #4  0x00007f5c6f110dfc n/a (libc.so.6 + 0x110dfc)
                                                  ELF object binary architecture: AMD x86-64

An extra null pointer check is not needed in functions like the following.

• AppearancePage
• Qt6CTPlatformTheme
• TroubleshootingPage::on_removeAppButton_clicked

I've used qt5ct and qt6ct to set custom styles for my qt apps, this works great for most apps and I've been using that.
But there's a bit of snag, KDE Connect and Tokodon seem to ignore the configured style.

Ark left has the theme applied; whilst Tokodon and KDE Connect fall back to their default light theme.

I have noticed that Kde Connect and Tokodon are a bit different compared to other Qt apps with a header bar and more mobile-forward and responsive layout; but I don't see why they wouldn't be styled by the Qt theme.

I can however confirm that this shouldn't be a configuration issue as both Qt5 and Qt6 applications work fine and without any major issues.

When using the above environment variable, the bold text (either set by Qt Designer or <b></b> tags) appears fuzzy.

Notice the QRadioButton labels on the left and the rightmost labels.

In contrast with QT_QPA_PLATFORMTHEME unset, the bold text appears correct.

This is with the default qt5ct configuration with DejaVu Sans font size 9

The same behavior is present in Qt6 with qt6ct. qt5ct version is 1.7, and qt6ct is 0.8 from the Arch repositories.

I have tested this with a few applications, some of my own so I can provide any more information if required.

When you run qt6ct and choose "darker" theme and then run any application that uses qt6, part of the texts are black. Which on a dark background is very hard to read, nearly impossible (depending on the app) and eye-straining:

This particular screenshot is from mkvtoolnix-gui but the same problem occurs with other applications as well, such as qbittorrent. The regular qbittorrrent uses qt6, so until this problem is resolved, I had to switch to qbittorrent-qt5. But mkvtoolnix-gui doesn't have a qt5 build, so fixing the reported problem would be much appreciated.

For comparison - there are no black texts in "darker" theme when the app is using qt5.

Does not build reproducibly, as NT_GNU_BUILD_ID varies between builds.

Can be fixed by adding
set(CMAKE_BUILD_RPATH_USE_ORIGIN ON)
to CMakeLists.txt

See
https://reproducible-builds.org/docs/deterministic-build-systems/#cmake-notes

It's really inconvenient to use Qt5&Qt6 apps together since it's impossible to set multiple values to QT_QPA_PLATFORMTHEME. Since qt5ct & qt6ct almost identical, why not to support both Qt versions in one codebase with support to build both variants? That way, it would be possible to set QT_QPA_PLATFORMTHEME=qtct and have all Qt applications styled.

When you have qt6ct and kvantum installed, what would usually happen is that qt6ct shows kvantum as an available option in the drop-down menu in the "appearance" tab to use to theme QT programs (the correct behavior that qt5ct shows).

Instead, qt6ct simply ignores that kvantum is an option.

Reproducible: Always

Steps to Reproduce:

1. install the "qt6ct" and kvantum "packages"
2. launch qt6ct
3. try to find the kvantum option in the drop down menu inside qt6ct's appearance tab.
   Actual Results:
   No kvantum option appeared in the dropdown menu.

Expected Results:
You should see the kvantum option in the dropdown menu.

I suspect that this bug is related specifically to qt6ct because kvantum can theme programs without problems if it's selected as one of the theming options inside KDE's appearance settings.

This problem is also present on Debian 12 and Ubuntu 23.10, if someone figures out a solution please tell the developers on charge of these packages in their respective distros to fix it.
With urgency!!! Ubuntu 24.04 LTS is around the corner.

Here is a link that displays the bug graphically, 1 picture is worth more than 1000 words:

Version 0.5; Qt version 6.2.2

I don't use qt6-based applications often, and today I suddenly noticed that qt6ct did not work. Here's the full error message:

$ qt6ct
No protocol specified
No protocol specified
No protocol specified
Configuration path: "/home/ellis/.config/qt6ct"
Shared QSS paths: QList("/home/ellis/.local/share/qt6ct/qss", "/home/ellis/.local/share/flatpak/exports/share/qt6ct/qss", "/var/lib/flatpak/exports/share/qt6ct/qss", "/usr/local/share/qt6ct/qss", "/usr/share/qt6ct/qss")
Shared color scheme paths: QList("/home/ellis/.local/share/qt6ct/colors", "/home/ellis/.local/share/flatpak/exports/share/qt6ct/colors", "/var/lib/flatpak/exports/share/qt6ct/colors", "/usr/local/share/qt6ct/colors", "/usr/share/qt6ct/colors")

(qt6ct:666): GLib-GObject-WARNING **: 22:51:58.005: cannot register existing type 'GdkDisplayManager'

(qt6ct:666): GLib-CRITICAL **: 22:51:58.005: g_once_init_leave: assertion 'result != 0' failed

(qt6ct:666): GLib-GObject-CRITICAL **: 22:51:58.005: g_object_new_with_properties: assertion 'G_TYPE_IS_OBJECT (object_type)' failed

(qt6ct:666): GLib-GObject-WARNING **: 22:51:58.005: invalid (NULL) pointer instance

(qt6ct:666): GLib-GObject-CRITICAL **: 22:51:58.005: g_signal_connect_data: assertion 'G_TYPE_CHECK_INSTANCE (instance)' failed

(qt6ct:666): GLib-GObject-WARNING **: 22:51:58.005: invalid (NULL) pointer instance

(qt6ct:666): GLib-GObject-CRITICAL **: 22:51:58.005: g_signal_connect_data: assertion 'G_TYPE_CHECK_INSTANCE (instance)' failed
No protocol specified

(qt6ct:666): GLib-GObject-WARNING **: 22:51:58.006: cannot register existing type 'GdkDisplay'

(qt6ct:666): GLib-CRITICAL **: 22:51:58.006: g_once_init_leave: assertion 'result != 0' failed

(qt6ct:666): GLib-GObject-CRITICAL **: 22:51:58.006: g_type_register_static: assertion 'parent_type > 0' failed

(qt6ct:666): GLib-CRITICAL **: 22:51:58.006: g_once_init_leave: assertion 'result != 0' failed

(qt6ct:666): GLib-GObject-CRITICAL **: 22:51:58.006: g_object_new_with_properties: assertion 'G_TYPE_IS_OBJECT (object_type)' failed
Segmentation fault (core dumped)

Here's my config:

[Appearance]
color_scheme_path=/usr/share/qt6ct/colors/darker.conf
custom_palette=false
icon_theme=Papirus-Dark
standard_dialogs=gtk2
style=gtk2

[Fonts]
fixed=@Variant(\0\0\0@\0\0\0\n\0S\0\x65\0r\0i\0\x66@$\0\0\0\0\0\0\xff\xff\xff\xff\x5\x1\0\x32\x10)
general=@Variant(\0\0\0@\0\0\0\n\0S\0\x65\0r\0i\0\x66@$\0\0\0\0\0\0\xff\xff\xff\xff\x5\x1\0\x32\x10)

[Interface]
activate_item_on_single_click=1
buttonbox_layout=3
cursor_flash_time=1000
dialog_buttons_have_icons=1
double_click_interval=400
gui_effects=@Invalid()
keyboard_scheme=2
menus_have_icons=true
show_shortcuts_in_context_menus=true
stylesheets=@Invalid()
toolbutton_style=4
underline_shortcut=1
wheel_scroll_lines=3

[SettingsWindow]
geometry=@ByteArray(\x1\xd9\xd0\xcb\0\x3\0\0\0\0\x3\xd5\0\0\0\0\0\0\x6\xb9\0\0\x2\x83\0\0\x3\xd8\0\0\0\x18\0\0\x6\xb6\0\0\x2\x80\0\0\0\0\0\0\0\0\a\x80\0\0\x3\xd8\0\0\0\x18\0\0\x6\xb6\0\0\x2\x80)

[Troubleshooting]
force_raster_widgets=1
ignored_applications=@Invalid()

I'm sorry about this, but I am really uncertain as to the cause of this bug. And I cannot recall exactly what had happened since the last time it had run without a hitch.

A quick Google search told me that GTK cannot register existing type 'GdkDisplayManager' because there are multiple versions of GTK installed. It is true that I recently installed GTK 4 out of curiosity (my distro still uses GTK 2/3), but even if I have completely removed the packages, the problem still persists.

And if my memory serves me correctly, there has recently been a Qt 6 update. So I rebuilt qt6ct and qt6gtk2—well, it ain't work, either.

With qt6ct 0.9, a dark kvantum theme (I was using KvGnomeDark), together with the "Default" palatte in qt6ct, theming e.g. aur/nheko-git seems to be broken, with e.g. dark text on dark background:

As a comparison, here's the same setup but with qt6ct 0.8:

git bisect points to 8ac0c7d as the first bad commit.

How can I set the cursor theme?

I have installed nordzy-cursors and copied /usr/share/icons/nordzy-cursors into both ~/.local/share/icons and ~/.icons, but still it doesn't show up in qt6ct's "Icon theme" tab and in any case there is not tab to select a cursor different from the icon theme.

I tested qt6ct same settings as qt5ct, but kvantum style is not applied. In addition, in standard dialogs I see Default, GTK3, but KDE is not present there.

💭 Would you like to wrap any pointer data members with the class template “std::unique_ptr”?

thanks for working on qt6ct!

I'm using qt6ct without any style sheets checked, Windows theme. Some applications are broken with it, here are some examples

pavucontrol-qt

qt6ct introduces a horizontal scrollbar, so I need to scroll in order to mute. The vanilla one adapts itself to the size of the window.

vanilla

qt6ct

mumble

qt6ct sets the "configure" floating window to monitor width and it's impossible to resize, I can resize the vanilla up to what the vanilla picture shows, then I can't resize down anymore.

vanilla

qt6ct

I had problems with a some other applications too.. It wasn't always like this if I remember correctly, some update broke it

when i use both these settings it doesn't seem to work and be able to use dark mode

QPlatformTheme::HoverEffect is defined in https://invent.kde.org/qt/qt/qtbase/-/blob/6.6.1/src/gui/kernel/qplatformtheme.h#L264-L274.

According to https://invent.kde.org/qt/qt/qtbase/-/blob/6.6.1/src/gui/kernel/qstylehints.cpp?ref_type=heads#L501-L517 and https://invent.kde.org/qt/qt/qtbase/-/blob/dev/src/gui/platform/unix/qgenericunixthemes.cpp#L503-L504, this should be enabled by default on desktop platforms.

However, qt6ct provides no interface to enable this and the current only way is to delete the line starting with gui_effects in the config file, to force a fallback on QGenericUnixTheme::themeHint(QPlatformTheme::UiEffects). That is however reset whenever one apply settings through the GUI.

I installed qt6ct on my Linux Mint 21.3 Cinnamon Machine (based on Ubuntu 22.04), which already has qt5ct configured.

As far as I understand, the existing setting of QT_QPA_PLATFORMTHEME=qt5ct should be fine for qt6ct as well (It is set in a XSession config file).

I also installed qt6gtk2, as I don't know how else to select the GTK platformtheme in qt6ct as nothing showed up for GTK 3 or similar.

After doing this, the option is now showing up in the theme selection dropdown, but as soon as I select it, the program crashes with a segmentation fault and the following output:

Configuration path: "/home/<user>/.config/qt6ct"
Shared QSS paths: QList("/home/<user>/.local/share/qt6ct/qss", "/usr/share/cinnamon/qt6ct/qss", "/usr/share/gnome/qt6ct/qss", "/home/<user>/.local/share/flatpak/exports/share/qt6ct/qss", "/var/lib/flatpak/exports/share/qt6ct/qss", "/usr/local/share/qt6ct/qss", "/usr/share/qt6ct/qss")
Shared color scheme paths: QList("/home/<user>/.local/share/qt6ct/colors", "/usr/share/cinnamon/qt6ct/colors", "/usr/share/gnome/qt6ct/colors", "/home/<user>/.local/share/flatpak/exports/share/qt6ct/colors", "/var/lib/flatpak/exports/share/qt6ct/colors", "/usr/local/share/qt6ct/colors", "/usr/share/qt6ct/colors")

(qt6ct:8137): GLib-GObject-WARNING **: 19:42:39.633: cannot register existing type 'GdkDisplayManager'

(qt6ct:8137): GLib-CRITICAL **: 19:42:39.633: g_once_init_leave: assertion 'result != 0' failed

(qt6ct:8137): GLib-GObject-CRITICAL **: 19:42:39.633: g_object_new_with_properties: assertion 'G_TYPE_IS_OBJECT (object_type)' failed

(qt6ct:8137): GLib-GObject-WARNING **: 19:42:39.633: invalid (NULL) pointer instance

(qt6ct:8137): GLib-GObject-CRITICAL **: 19:42:39.633: g_signal_connect_data: assertion 'G_TYPE_CHECK_INSTANCE (instance)' failed

(qt6ct:8137): GLib-GObject-WARNING **: 19:42:39.633: invalid (NULL) pointer instance

(qt6ct:8137): GLib-GObject-CRITICAL **: 19:42:39.633: g_signal_connect_data: assertion 'G_TYPE_CHECK_INSTANCE (instance)' failed

(qt6ct:8137): GLib-GObject-WARNING **: 19:42:39.634: cannot register existing type 'GdkDisplay'

(qt6ct:8137): GLib-CRITICAL **: 19:42:39.634: g_once_init_leave: assertion 'result != 0' failed

(qt6ct:8137): GLib-GObject-CRITICAL **: 19:42:39.634: g_type_register_static: assertion 'parent_type > 0' failed

(qt6ct:8137): GLib-CRITICAL **: 19:42:39.634: g_once_init_leave: assertion 'result != 0' failed

(qt6ct:8137): GLib-GObject-CRITICAL **: 19:42:39.634: g_object_new_with_properties: assertion 'G_TYPE_IS_OBJECT (object_type)' failed
Speicherzugriffsfehler (Speicherabzug geschrieben)

This seems to be the issue from #16, but the fix described, so setting the variable in /etc/environment instead of the Xsession config file doesn't fix the issue for me.

I have an issue using qt6ct with qt creator. It correctly set's icon theme and color theme to make creator operate effectively on GNOME, including allowing me to style the designer UI in dark mode. But, it messes with the font within the editor.

Because the font setting is very one-size-fits all, it makes the normally bold elements within the editor go away so all text is "Regular" while the default behavior in Qt Creator is to make certain code elements bold.

If there was a checkbox to not write any font setting to the config nor have any default font setting injected into the Qt app, this problem would be solved, then I could still use the icon and color scheme settings alone but let Creator control fonts completely.

Desired font style with some bold elements:

qt6ct theme applied, all text "Regular":

Breeze appears in the qt5ct, it doesn't appear to be in qt6ct. Is there some way to add it?

Hello

I am a distro maintainer (XeroLinux) on Gnome where I use this tool to theme Qt apps I recently enabled Wayland, unfortunately it ain't working at all .. I tried everything..

When I do the echo $QT_QPA_PLATFORMTHEME command I get nothing. What am I missing ?

(I'm not certain this is the best place to ask, thus please point me in the right direction.)

I am currently using i3 without any other Gnome / KDE components, and rely only on a handful Qt applications, that I used to configure via qt5ct, although now because they've switched to Qt6 I'm relying on qt6ct.

The problem is that now with Qt6 the vertical scrolling is "inverted" to the new default that I guess is "natural scrolling". However, I want my scroll to behave the "classical" way.

Is there a way in qt6ct to configure this override?

If not, this is a feature request. :)

If qt6ct is launched for the first time and quit by clicking OK, the majority of settings is saved in ~/.config/qt6ct/qt6ct.conf, but the icon theme isn't. In order to have it saved in qt6ct.conf, its entry in tab "Icon Theme" has to be highlighted by clicking first.
This is inconsistent and can, more importantly, be pretty confusing when launching qt6ct the first time. So I think it would be good, if the icon theme could be saved the same way as the other settings.

Steps to reproduce:

1. Make sure qt6ct isn't running and ~/.config/qt6ct/ is absent.
2. Launch qt6ct and quit it by hitting OK without taking any action.
3. Open qt6ct.conf. The icon theme will be missing in section [Appearance].
4. Launch qt6ct again, highlight an icon theme in tab "Icon Theme" by clicking its entry, quit by clicking OK.
5. Open qt6ct.conf. The icon theme is now present in section [Appearance].

Seen running 55dba87 on Arch Linux.

Im getting these errors when I try to Cmake this project

The CXX compiler identification is GNU 10.2.0
Detecting CXX compiler ABI info
CMake Warning (dev) at /home/pc/Qt/Tools/CMake/share/cmake-3.19/Modules/CMakeDetermineCompilerABI.cmake:48 (try_compile):
try_compile given unknown argument "--no-warn-unused-cli".
Call Stack (most recent call first):
/home/pc/Qt/Tools/CMake/share/cmake-3.19/Modules/CMakeTestCXXCompiler.cmake:26 (CMAKE_DETERMINE_COMPILER_ABI)
CMakeLists.txt:3 (project)
This warning is for project developers. Use -Wno-dev to suppress it.

CMake Error at /home/pc/Qt/Tools/CMake/share/cmake-3.19/Modules/CMakeDetermineCompilerABI.cmake:48 (try_compile):
COMPILE_DEFINITIONS specified on a srcdir type TRY_COMPILE
Call Stack (most recent call first):
/home/pc/Qt/Tools/CMake/share/cmake-3.19/Modules/CMakeTestCXXCompiler.cmake:26 (CMAKE_DETERMINE_COMPILER_ABI)
CMakeLists.txt:3 (project)

Detecting CXX compiler ABI info - failed
Check for working CXX compiler: /usr/bin/c++
CMake Error at /home/pc/Qt/Tools/CMake/share/cmake-3.19/Modules/CMakeTestCXXCompiler.cmake:46 (try_compile):
Failed to set working directory to /CMakeFiles/CMakeTmp/testCXXCompiler.cxx
: Not a directory
Call Stack (most recent call first):
CMakeLists.txt:3 (project)

Configuring incomplete, errors occurred!
See also "/CMakeFiles/CMakeOutput.log".
See also "/CMakeFiles/CMakeError.log".

Is it possible to auto sync the icons and font with the ones used by the system? This is important for a GTK based system to also force the same font on QT apps, if it makes sense.

Hello! If I just select some color scheme, everything works fine. But if I try to enable Style Sheets, i.e. tooltip-simple.qss (or any other), then my color scheme starts to glitch - some parts of background color, borders, etc. looses all colors from selected scheme. When disabling any of *.qss in Style Sheets, glitch disappears.

qt6ct enabled with export QT_QPA_PLATFORMTHEME="qt5ct" in ~/.profile

ignore this im stupid

I'm trying to create a package for Void Linux and the build fails with the following error message:

https://ftp.pcre.org/pub/pcre/pcre-8.44.tar.bz2: Connection timed out
=> ERROR: pcre-8.44_1: failed to fetch pcre-8.44.tar.bz2.

I went to the PCRE homepage and there is no mention of this ftp server anymore, only their GitHub repository and the inofficial SourceForge mirror. I would just use the version packaged with Void Linux, but they are already at version 8.45, so the build script will still try to fetch the older version. Is there a way to build this anyway? Thanks for your help.

Hey everyone :-)

Just wondering if some command line argument functionality could be added so I can control the application with scripting. Specifically I am interesting in scripting some day/night switching with the new KDE theme support introduced in #43. My apologies if there is also this functionality, just haven't been able to find documentation if that is the case.

This is pretty bad, and makes Qt look bad. We got a bug report from a user at https://bugreports.qt.io/browse/QTBUG-106375

Unfortunately Manjaro is shipping qt6ct pre-installed. They need to stop doing that too, if you don't fix it ASAP. I can't believe they ship such things without testing anything with Qt Quick.

I didn't dig deeper to see what the actual problem is.

Actually, even qtdiag crashes with this theme plugin.

Arch Linux, qt6ct 0.6-2. Application is unable to be launched at all, immediately core dumping.

The core dump: https://envs.sh/QzN.core
The coredump info:

           PID: 6243 (qt6ct)
           UID: 1000 (rensenware)
           GID: 998 (wheel)
        Signal: 11 (SEGV)
     Timestamp: Thu 2022-10-06 00:27:25 EDT (2min 39s ago)
  Command Line: qt6ct
    Executable: /usr/bin/qt6ct
 Control Group: /user.slice/user-1000.slice/[email protected]/app.slice/app-org.gnome.Terminal.slice/vte-spawn-26fcd03d-5baa-44b9-b6df-a2fcb76add11.scope
          Unit: [email protected]
     User Unit: vte-spawn-26fcd03d-5baa-44b9-b6df-a2fcb76add11.scope
         Slice: user-1000.slice
     Owner UID: 1000 (rensenware)
       Boot ID: edda17bcabaf4254944c8e2a18e29a74
    Machine ID: fe86cd201ca345bfbbaa51d5eb43c909
      Hostname: t480-arch
       Storage: /var/lib/systemd/coredump/core.qt6ct.1000.edda17bcabaf4254944c8e2a18e29a74.6243.1665030445000000.zst (present)
     Disk Size: 470.3K
       Message: Process 6243 (qt6ct) of user 1000 dumped core.
                
                Module linux-vdso.so.1 with build-id 5be7b2f03b3bbc1efefa813e8d744334e2b67b34
                Module libqt6ct.so with build-id f2fcb06511256a7438b9143075a998217df45b5f
                Module libffi.so.8 with build-id fb5dba105458f179a9153659f3ccd8e1056a2f35
                Module libwayland-cursor.so.0 with build-id 46a637dbcbb02d6712a201f177377b66598b9121
                Module libwayland-client.so.0 with build-id 515c72111400d7bdbfbdfcec78d597e4986a5943
                Module libQt6WaylandClient.so.6 with build-id 23696013e6a99f05a335ed7c92452f1b3245043a
                Module libqwayland-generic.so with build-id 1a065f1a8ac86178d1bc6133fd6f75db2c7dcc7d
                Module libgpg-error.so.0 with build-id 4738b8a9478177c202cccd64e0eb65d3dea2bfae
                Module libbrotlicommon.so.1 with build-id acfd597a977c8087bb6184383daae2e828a9ce42
                Module libXdmcp.so.6 with build-id d864159ab0008415667db8d5f251696d75c90df2
                Module libXau.so.6 with build-id d9d5e8277140f1a86d3a07d9b52b1703c0a2f9a8
                Module libgomp.so.1 with build-id 117ab7458eb756ac0e9e4791c510ae72fe710bd5
                Module liblz4.so.1 with build-id 84ea95d811dad359e94e100ebe6a746294ffe8a7
                Module liblzma.so.5 with build-id 8a7334fec02fef6a82ff641a68b3e3200a44a702
                Module libgcrypt.so.20 with build-id 8bf3cb884124273640de797a3e77d86c98434ea4
                Module libcap.so.2 with build-id 9b38b08de708f439a9d0a4f8b9914151bc8d4b50
                Module libicudata.so.71 with build-id 4fef196388e678deb881978139e125e20ee2d94d
                Module libbrotlidec.so.1 with build-id 66c54e9301f7e102ecc1d88547e5f0e8a056fe22
                Module libbz2.so.1.0 with build-id 919597c477c9b2cb9cdbb7745ed6494ac0e6da60
                Module libgraphite2.so.3 with build-id ce58945ebb55b86d3a4e717b6eae29efc4720d8e
                Module libdbus-1.so.3 with build-id 6dece245a58f1549ed98431e1242f487e8ebf9a2
                Module libpcre2-8.so.0 with build-id 917fc43d2c9f8539a3e324555c6c73886e8000a8
                Module libxcb.so.1 with build-id 13d677412a71468381b11092915d231f664d18d3
                Module libexpat.so.1 with build-id 52f685635e8711c1164d20a1ef8acd3840312094
                Module libGLdispatch.so.0 with build-id 7879a881271650eff97c35aff7a8674859c5ae94
                Module libzstd.so.1 with build-id ab54c2881f53ab314e134f3e08c76d504376dd5d
                Module libpcre2-16.so.0 with build-id 8ad49680a3f743a5241632a400d0de30aeaa54dd
                Module libb2.so.1 with build-id e39ae9514401c72c0e5cafa1abe0741360c22e87
                Module libdouble-conversion.so.3 with build-id 74bfa78f70f9ae1f759f0ae383fbc7f6f7faf6f8
                Module libsystemd.so.0 with build-id 63caa6a43422a3b88218d35317cf7611aa9f51ef
                Module libicuuc.so.71 with build-id 633fdc0c5385d916571f6140e7a978ad0630ef55
                Module libicui18n.so.71 with build-id 6fd5c97fd2808ee29958bf809656d5885e7e8963
                Module libz.so.1 with build-id fefe3219a96d682ec98fcfb78866b8594298b5a2
                Module libfreetype.so.6 with build-id f89dd5502e75aca28fb5c3ccd0dbd26fe822bfef
                Module libmd4c.so.0 with build-id 2151dba72cdc9960097e6e960a58a2f03c8bb96e
                Module libharfbuzz.so.0 with build-id 0083e085bcb9cb3869e5cb05fbcd9736c41434ab
                Module libpng16.so.16 with build-id 14d3b3cc9d61ec1b7c1f86bdf108218a99364945
                Module libOpenGL.so.0 with build-id 3df533822644f44fa89abdb75b9f89220dfdee56
                Module libGLX.so.0 with build-id d2c37fb8ec3bc53c67c013b0c6ac63ec086c8883
                Module libxkbcommon.so.0 with build-id 6cf66eead3fcc20fe5df10162bfbcdcdc8b2a183
                Module libQt6DBus.so.6 with build-id cd5a01c0313f99f4d1009205cddccff5d860bd6c
                Module libglib-2.0.so.0 with build-id 3ef8f9239c93af698703b12c5c6738fe0129eaa7
                Module libX11.so.6 with build-id 21e886e968772b7964d646f54c1faecc56734de9
                Module libfontconfig.so.1 with build-id 36be6951b8c1e42a7dd05684a37400fc8ef9147c
                Module libEGL.so.1 with build-id 14389538015bb4a3a44e794e2466e31bf0834209
                Module libm.so.6 with build-id 8a4929d22ebcbb96a075a378918a2804f49ca28f
                Module ld-linux-x86-64.so.2 with build-id 44db3ccb9e01b83c9cff0216f36e26d90c1ba85d
                Module libc.so.6 with build-id 21a9a7f001414ad7fce50b6aeb125889f39499d0
                Module libgcc_s.so.1 with build-id 85db482c4585a328d95ec41124337a967bb24d8f
                Module libstdc++.so.6 with build-id 735a3d0cc7699fd69337361cba4aedb644b2a7ed
                Module libQt6Core.so.6 with build-id 58691aace71818944994ca8feaf835e774031d59
                Module libQt6Gui.so.6 with build-id fc60e808c0e0f8caef00cfdb1f0feae4b6702759
                Module libQt6Widgets.so.6 with build-id fb5fb1f09b6a1ddefd2c330d68dc538a75bbfa91
                Module qt6ct with build-id 6114e2bce433d0cf298dbee6a084060205c92306
                Stack trace of thread 6243:
                #0  0x00007fa46e38547c _ZNK5QFonteqERKS_ (libQt6Gui.so.6 + 0x38547c)
                #1  0x00007fa46e38586e _ZNK5QFontneERKS_ (libQt6Gui.so.6 + 0x38586e)
                #2  0x00007fa46e1a40a2 _ZN15QGuiApplication7setFontERK5QFont (libQt6Gui.so.6 + 0x1a40a2)
                #3  0x00007fa46a7adaad _ZN18Qt6CTPlatformThemeC2Ev (libqt6ct.so + 0xaaad)
                #4  0x00007fa46a7a9f5b _ZN24Qt6CTPlatformThemePlugin6createERK7QStringRK5QListIS0_E (libqt6ct.so + 0x6f5b)
                #5  0x00007fa46e1cfd0d _ZN21QPlatformThemeFactory6createERK7QStringS2_ (libQt6Gui.so.6 + 0x1cfd0d)
                #6  0x00007fa46e1960b0 _ZN22QGuiApplicationPrivate25createPlatformIntegrationEv (libQt6Gui.so.6 + 0x1960b0)
                #7  0x00007fa46e197bc9 _ZN22QGuiApplicationPrivate21createEventDispatcherEv (libQt6Gui.so.6 + 0x197bc9)
                #8  0x00007fa46db2f28c _ZN23QCoreApplicationPrivate4initEv (libQt6Core.so.6 + 0x12f28c)
                #9  0x00007fa46e197c51 _ZN22QGuiApplicationPrivate4initEv (libQt6Gui.so.6 + 0x197c51)
                #10 0x00007fa46e96cade _ZN19QApplicationPrivate4initEv (libQt6Widgets.so.6 + 0x16cade)
                #11 0x0000564f34006994 main (qt6ct + 0x13994)
                #12 0x00007fa46d43d290 n/a (libc.so.6 + 0x23290)
                #13 0x00007fa46d43d34a __libc_start_main (libc.so.6 + 0x2334a)
                #14 0x0000564f34006fe5 _start (qt6ct + 0x13fe5)
                ELF object binary architecture: AMD x86-64

GNOME 42 on Wayland. I've tried messing around with running on xorg, making sure everything in the xorg group is installed, etc. Nothing works.

The gdb bt:

#0  0x00007fa46e38547c in QFont::operator==(QFont const&) const () from /usr/lib/libQt6Gui.so.6
#1  0x00007fa46e38586e in QFont::operator!=(QFont const&) const () from /usr/lib/libQt6Gui.so.6
#2  0x00007fa46e1a40a2 in QGuiApplication::setFont(QFont const&) () from /usr/lib/libQt6Gui.so.6
#3  0x00007fa46a7adaad in Qt6CTPlatformTheme::Qt6CTPlatformTheme (this=this@entry=0x564f359ffe90) at /usr/src/debug/qt6ct-0.6/src/qt6ct-qtplugin/qt6ctplatformtheme.cpp:69
#4  0x00007fa46a7a9f5b in Qt6CTPlatformThemePlugin::create (this=<optimized out>, key=..., params=...) at /usr/src/debug/qt6ct-0.6/src/qt6ct-qtplugin/main.cpp:54
#5  0x00007fa46e1cfd0d in QPlatformThemeFactory::create(QString const&, QString const&) () from /usr/lib/libQt6Gui.so.6
#6  0x00007fa46e1960b0 in QGuiApplicationPrivate::createPlatformIntegration() () from /usr/lib/libQt6Gui.so.6
#7  0x00007fa46e197bc9 in QGuiApplicationPrivate::createEventDispatcher() () from /usr/lib/libQt6Gui.so.6
#8  0x00007fa46db2f28c in QCoreApplicationPrivate::init() () from /usr/lib/libQt6Core.so.6
#9  0x00007fa46e197c51 in QGuiApplicationPrivate::init() () from /usr/lib/libQt6Gui.so.6
#10 0x00007fa46e96cade in QApplicationPrivate::init() () from /usr/lib/libQt6Widgets.so.6
#11 0x0000564f34006994 in main (argc=<optimized out>, argv=<optimized out>) at /usr/src/debug/qt6ct-0.6/src/qt6ct/main.cpp:40

this is on nixos, where qtbase is read only

-- Installing: /nix/store/wzms2f5b1014knb4dl72s66rmk3d2401-qtbase-6.2.2-bin/lib/qt-6.2.2/plugins/platformthemes/libqt6ct.so
CMake Error at src/qt6ct-qtplugin/cmake_install.cmake:60 (file):
  file INSTALL cannot copy file
  "/build/source/build/src/qt6ct-qtplugin/libqt6ct.so" to
  "/nix/store/wzms2f5b1014knb4dl72s66rmk3d2401-qtbase-6.2.2-bin/lib/qt-6.2.2/plugins/platformthemes/libqt6ct.so":
  Permission denied.
Call Stack (most recent call first):
  cmake_install.cmake:52 (include)


make: *** [Makefile:100: install] Error 1

fix: allow to set PLUGINDIR with cmake -DPLUGINDIR=/some/where/else
also qt5ct allows to set PLUGINDIR

--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -39,8 +39,10 @@
     message(FATAL_ERROR "Could NOT find lrelease executable")
 endif()
 
-#execute_process(COMMAND ${QT_QTPATHS_EXECUTABLE} -query QT_INSTALL_PLUGINS OUTPUT_VARIABLE PLUGINDIR OUTPUT_STRIP_TRAILING_WHITESPACE)
-execute_process(COMMAND ${QT_QTPATHS_EXECUTABLE} --plugin-dir OUTPUT_VARIABLE PLUGINDIR OUTPUT_STRIP_TRAILING_WHITESPACE)
+if(NOT DEFINED PLUGINDIR)
+    #execute_process(COMMAND ${QT_QTPATHS_EXECUTABLE} -query QT_INSTALL_PLUGINS OUTPUT_VARIABLE PLUGINDIR OUTPUT_STRIP_TRAILING_WHITESPACE)
+    execute_process(COMMAND ${QT_QTPATHS_EXECUTABLE} --plugin-dir OUTPUT_VARIABLE PLUGINDIR OUTPUT_STRIP_TRAILING_WHITESPACE)
+endif()
 message(STATUS "Plugin path: " ${PLUGINDIR})
 
 message(STATUS "Generating translations ...")

Hello, I have an issue with theme not applying when I use qt6ct.

I have the environment variables set and, the theme works on qt6ct itself. However it doesn't seem to be affecting other QT applications I have like Dolphin or VirtualBox.

Preview:

I've tried doing QT_QPA_PLATFORMTHEME=qt6ct virtualbox, but that doesn't make the theme apply either. I've also tried QT_QPA_PLATFORMTHEME=qt6gtk2 since it was stated as a possible way to set QT theme to use GTK2 on the arch wiki.

I've tried other methods of applying QT, but the only one I've ever gotten to "work" is kvantum. And even then the UIs are pretty broken. For instance, dark icons on a dark theme when I use dolphin. I've never actually seen a QT theme working well outside of KDE.

I use Fedora 37 (Workstation Editon). qt6ct 0.7-1.fc37 currently does not function anymore due to recent package updates to Qt6. The newest available version is now 6.4.1, not 6.3.1.

Description of problem:
Every time I start it from console

Version-Release number of selected component:
qt6ct-0.5-2.fc36

Additional info:
reporter: libreport-2.17.1
backtrace_rating: 4
cgroup: 0::/user.slice/user-1000.slice/[email protected]/app.slice/app-glib-qt6ct-2743.scope
cmdline: qt6ct
crash_function: qt_message_fatal
executable: /usr/bin/qt6ct
journald_cursor: s=b2b1c68c4d6f4957be3c182b0f95f08b;i=d847;b=6446647ebe1e47e99b01761236ceb3b6;m=401a6245;t=5de5ce335cea8;x=e349a00f81518a60
kernel: 5.17.5-300.fc36.x86_64
rootdir: /
runlevel: N 5
type: CCpp
uid: 1000

Truncated backtrace:
Thread no. 1 (9 frames)
#4 qt_message_fatal at /usr/src/debug/qt6-qtbase-6.2.3-2.fc36.x86_64/src/corelib/global/qlogging.cpp:1905
#5 QMessageLogger::fatal at /usr/src/debug/qt6-qtbase-6.2.3-2.fc36.x86_64/src/corelib/global/qlogging.cpp:890
#6 qt_pixmap_thread_test at /usr/src/debug/qt6-qtbase-6.2.3-2.fc36.x86_64/src/gui/image/qpixmap.cpp:81
#8 QPixmap::QPixmap at /usr/src/debug/qt6-qtbase-6.2.3-2.fc36.x86_64/src/gui/image/qpixmap.cpp:110
#9 QPixmapIconEngineEntry::QPixmapIconEngineEntry at /usr/src/debug/qt6-qtbase-6.2.3-2.fc36.x86_64/src/gui/image/qicon_p.h:102
#10 QPixmapIconEngine::addFile at /usr/src/debug/qt6-qtbase-6.2.3-2.fc36.x86_64/src/gui/image/qicon.cpp:463
#11 QIcon::addFile at /usr/src/debug/qt6-qtbase-6.2.3-2.fc36.x86_64/src/gui/image/qicon.cpp:1113
#13 QIcon::QIcon at /usr/src/debug/qt6-qtbase-6.2.3-2.fc36.x86_64/src/gui/image/qicon.cpp:729
#14 IconThemePage::findIcon at /usr/src/debug/qt6ct-0.5-2.fc36.x86_64/src/qt6ct/iconthemepage.cpp:227

Fedora bugzilla with all log files.

see lxqt/lxqt#2221