The reason for incomplete character display in the Designer UI dialog on Linux might be caused by the following factors

[Terracotta-6]

Main Causes

1. Font Rendering Differences:

   • Linux uses different font rendering systems (such as FreeType, Fontconfig), which differ from font
     rendering on Windows or macOS
   • Qt's font metric calculations on Linux may not match the actual display

2. DPI and Scaling Settings:

   • DPI settings or scaling ratios in Linux desktop environments may not match the application's expectations
   • Scaling factors on high-DPI displays cause layout calculation errors

3. Qt Styles and Themes:

   • Linux desktop environment's GTK/Qt themes may affect dialog layout
   • Different UI element margins and font size settings

4. Window Manager Behavior:

   • Different window managers on Linux may handle initial dialog dimensions differently
   • Incorrect dimension calculations when dialogs are created

Why Characters Display Properly After Maximize and Restore?

When the dialog is maximized and then restored, the following operations are triggered:

• Recalculating layout and font sizes
• Qt remeasures text and UI element dimensions
• Triggering resize events to readjust controls to fit content

Potential Solutions

1. Check Qt Font Settings:

   Ensure correct font metrics in code

   font_metrics = QFontMetrics(font)
   width = font_metrics.width(text)

2. Adjust Dialog Initialization Code:

   • Use adjustSize() or resize() when creating dialogs to ensure proper dimensions
   • Use layout managers to ensure content adaptability

3. Linux-specific Settings:

   • Set environment variables such as QT_FONT_DPI or QT_AUTO_SCREEN_SCALE_FACTOR
   • Check font settings in ~/.Xresources or desktop environment

✦ This issue is likely related to Qt's font metrics and layout calculations on Linux. The maximize-then-restore
operation triggers a re-layout, resolving the initial dimension calculation errors.

[MAKOMO]

Are you using Wayland?

[Terracotta-6]

Yes, I'm using Wayland (default Ubuntu session).

[MAKOMO]

Hm. I cannot reproduce this on my Ubuntu 24.04 VM. Are you on 24.04?

Do you see this rendering issue with any save/open dialog? Note those are generated from the OS. Do you see this also in other apps on that machine?

[Terracotta-6]

I'm currently using Ubuntu 22.04 LTS and have confirmed that the issue is with Wayland. The dialog box works normally again after switching to X11.

[Terracotta-6]

After installing Ubuntu 24.04.3 LTS and testing Wayland, there are still minor issues.

The dialog box works normally again after switching to X11.

Testing is finished; closing this discussion thread.