small cursor with linuxbrew install on archlinux with lightdm and i3

[ipatch]

for reasons i do not understand the mouse cursor scales down in size when moving it inside of the main freecad gui window with my current setup of arch linux, lightdm, and i3.

[ipatch]

a couple of notes, setting the below environment variable did not change the cursor size,

export XCURSOR_SIZE=24

setting the below env var scales all the gui contents in the window to a much smaller size than seen in the previous image.

export QT_AUTO_SCREEN_SCALE_FACTOR=0

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unlinking qt6 using brew unlink qt followed by brew link qt@5 did not change the cursor size nor did setting the below environment variables.

export QT_QPA_PLATFORM_PLUGIN_PATH=$bp/opt/qt5/plugins/platforms
export QT_QPA_PLATFORM=xcb

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https://discourse.ubuntubudgie.org/t/extremely-tiny-mouse-in-some-apps-qt-with-fractional-scaling-enabled/4456

[ipatch]

below are a couple other commands i have tried.

QT_SCALE_FACTOR=1.5 $bp/bin/freecad 

QT_AUTO_SCREEN_SCALE_FACTOR=1

neither of those environment variables adjusted the size of the cursor.

[ipatch]

a possible workaround is define a custom cursor and not use the default qt arrow cursor.

Qt.ArrowCursor

[ipatch]

spent some time this afternoon troubleshooting.

╰─λ strace -f -e trace=openat -o /tmp/fc-arch.log /usr/bin/freecad 2>&1 &
╭─capin at rogue in /home/capin
╰─λ FreeCAD 1.1.1, Libs: 1.1.1R44874 (Git)
(C) 2001-2026 FreeCAD contributors
FreeCAD is free and open-source software licensed under the terms of LGPL2+ license.
╭─capin at rogue in /home/capin
╰─λ
fish: Job 1, 'strace -f -e trace=openat -o /t…' has ended
╭─capin at rogue in /home/capin
╰─λ grep -iE 'cursor|xcursor' /tmp/fc-local.log | grep -v ENOENT | sort -u
1587796 openat(AT_FDCWD, "/home/capin/homebrew/opt/xcb-util-cursor/lib/libxcb-cursor.so.0", O_RDONLY|O_CLOEXEC) = 3
╭─capin at rogue in /home/capin
╰─λ grep -iE 'cursor|xcursor' /tmp/fc-arch.log | grep -v ENOENT | sort -u
1659440 openat(AT_FDCWD, "/usr/lib/qt6/plugins/platforms/../../../libxcb-cursor.so.0", O_RDONLY|O_CLOEXEC) = 3
1659440 openat(AT_FDCWD, "/usr/share/icons/Adwaita/cursors/col-resize", O_RDONLY|O_CLOEXEC) = 23
1659440 openat(AT_FDCWD, "/usr/share/icons/Adwaita/cursors/left_ptr", O_RDONLY|O_CLOEXEC) = 15
1659440 openat(AT_FDCWD, "/usr/share/icons/Adwaita/cursors/left_ptr", O_RDONLY|O_CLOEXEC) = 17
1659440 openat(AT_FDCWD, "/usr/share/icons/Adwaita/cursors/row-resize", O_RDONLY|O_CLOEXEC) = 23
1659440 openat(AT_FDCWD, "/usr/share/icons/Adwaita/cursors/wait", O_RDONLY|O_CLOEXEC) = 17

and

Python 3.13.13 (main, Apr  7 2026, 18:19:01) [GCC 15.2.0] on linux
Type 'help', 'copyright', 'credits' or 'license' for more information.
>>> # Gui.runCommand('Start_Start',0)
>>> # Gui.runCommand('Std_Workbench',7)
>>> # Gui.runCommand('Std_ViewStatusBar',1)
>>> from PySide6.QtGui import QGuiApplication, QCursor
>>> from PySide6.QtCore import Qt
>>> from PySide6.QtCore import Qt
>>> app = QGuiApplication.instance()
>>> app = QGuiApplication.instance()
>>> for s in app.screens():
...     print(f"{s.name()}: logicalDPI={s.logicalDotsPerInch():.0f}, physicalDPI={s.physicalDotsPerInch():.0f}, dpr={s.devicePixelRatio()}, geo={s.geometry().width()}x{s.geometry().height()}")
... 
eDP: logicalDPI=96, physicalDPI=96, dpr=2.3020833333333335, geo=1251x782
DisplayPort-1: logicalDPI=96, physicalDPI=69, dpr=2.3020833333333335, geo=1668x938
>>> # What does Qt think the default cursor size is?
>>> from PySide6.QtGui import QCursor, QPixmap
>>> c = QCursor(Qt.ArrowCursor)
>>> pm = c.pixmap()
>>> print(f"Default ArrowCursor pixmap size: {pm.size().width()}x{pm.size().height()}, dpr={pm.devicePixelRatio()}")
Default ArrowCursor pixmap size: 0x0, dpr=1.0
>>> 
>>> # Probe the current override cursor if any
>>> override = app.overrideCursor()
>>> if override:
...     pm = override.pixmap()
...     print(f"Override cursor: shape={override.shape()}, pixmap={pm.size().width()}x{pm.size().height()}")
... else:
...     print("No override cursor")
... 
No override cursor
>>> 

[ipatch]

current work around i can use with my local build of freecad on my arch linux box. the below command is compatible with fish shell 🐡

LD_PRELOAD=/usr/lib/libxcb-cursor.so.0 /opt/code/fcgit/installs/issue.tshooting.qt6.py313/bin/FreeCAD