Switch wallpaper according to light/dark theme changes

[wxmup]

Feature Description

I’d like Noctalia to support binding a wallpaper to each theme variant:

• Light theme → Wallpaper A
• Dark theme → Wallpaper B

When the theme switches (manually or automatically), Noctalia should switch to the corresponding wallpaper automatically (ideally using Noctalia’s existing wallpaper transition animation).

Why Is This Needed?

Noctalia already supports automatically switching between light/dark themes (e.g., based on location/time). In practice, users often want the wallpaper to follow the theme as well.

Right now this can be approximated with Hooks (Theme Changed → call ipc wallpaper set ...), but it can lead to a race/competition at login:

Example scenario:

1. Before shutdown, the system is in dark theme.
2. After reboot/login, the automatic theme logic decides it should be light theme (e.g., morning).
3. During session startup, Noctalia may first restore the previous dark theme and trigger the hook → wallpaper switches to dark wallpaper.
4. Immediately after, the system switches to light theme and triggers the hook again → wallpaper switches again to light wallpaper.

Result: the wallpaper transitions twice during login, and the first transition may still be in progress when the second starts.
Expected behavior: wallpaper should switch only once, based on the final theme state after startup has stabilized.

This happens frequently in a real workflow: using the PC at night (dark theme), shutting down, and then booting in the morning (light theme).

This feels like something Noctalia should handle internally, because Noctalia has the best knowledge of:

• when the theme state is “final” vs “intermediate” during startup,
• when wallpaper transitions are in progress,
• and how to avoid duplicate transitions.

Suggested Solutions

One possible implementation approach:

1. Add per-theme wallpaper settings

   • A “Light wallpaper” and “Dark wallpaper” entry in wallpaper settings (or theme settings).
   • Optional per-monitor overrides if Noctalia already supports per-monitor wallpaper.

2. Internal debounce / “final state wins” logic

   • If multiple theme changes happen within a short window during startup (or while restoring session), only apply the wallpaper change once, based on the final theme state.
   • Alternatively: queue wallpaper changes and cancel any in-progress/queued transition when a newer theme state arrives.

3. Startup alignment

   • After Noctalia finishes loading (or after the auto-theme decision is applied), sync wallpaper to the current theme exactly once.
   • This would prevent the “restore old theme then immediately switch” issue.

4. Expose as a first-class feature

   • This would remove the need for user-side hook scripts and avoid race conditions caused by external commands.

Additional Context

• Current workaround: use “Theme Changed” hook to run ipc call wallpaper set ..., but it’s susceptible to the startup race described above.
• I’m using niri (single monitor eDP-1), but I believe this can affect any setup where theme is automatically changed on login.

[fireirohuncle]

This would be a very useful improvement, I used something similar in dank material shell, it is very convenient when switching the theme

[onyx-tty]

I'd love to see that feature too. Sometimes day or night themes don't match the wallpaper very well.

[Ly-sec]

Thanks so much for reaching out and sharing this with us!

Right now, our team is entirely focused on building v5. Since the v4 lifecycle has officially come to an end, we are wrapping up old issues and won’t be shipping any further updates or fixes to that codebase.

We are closing this issue for now, but we truly appreciate you taking the time to report it. We aren’t quite ready to open up the v5 tracker for public bug reports or feature requests just yet, but we’ll definitely keep your feedback in mind as we develop the new version!

Cheers!