FS#2719Moiré Effect with QT6 on Linux when Display Scaling is > 100%
- Type
- Bug
- Status
- Closed
- Resolution
- Won't fix
- Category
- QCAD (main)
- Severity
- Low
- Priority
- Low
- Reported version
- 3.32.7
- Operating system
- Linux, Qt 6
- Reported
- 2026-05-03 by alex_holden
- Closed
- 2026-06-19 by andrew
I have noticed a problem that causes ugly rendering when using the QT6 version of 3.32.7 on KDE/XWayland if my system display scaling is set higher than 100%. The problem does not occur with QT5.
Attached screenshots were taken using QT5 and QT6 for comparison (both at 125% scaling). Antialiasing was turned off. Note how the grid dots fade in and out like a moiré pattern.
- QCAD_Rendering_Test.dxf112 KB
QCAD_Rendering_Example_QT5.png925 KB
QCAD_Rendering_Example_QT6.png838 KB
Closure comment
Likely a change in how Qt handles arbitrary UI scaling. Cannot be fixed on our end.