[itsmunzir]

Fixes #685.

Problem

With [backdrop] blur = true, the window is translucent on KDE Plasma 6.8 (Wayland) but the desktop behind it is not blurred. GPUI's Wayland backend (gpui-pre-linux 0.3.6, wayland/window.rs update_window) only binds org_kde_kwin_blur_manager. KWin 6.8 no longer advertises that global and offers the standard ext_background_effect_manager_v1 instead, so the blur request had nothing to bind to. Upstream Zed's gpui_linux has no ext_background_effect_v1 support yet either.

Approach

GPUI is pinned to an exact version, so this patches it in the repo:

1. build: vendor gpui-pre-linux 0.3.6 unmodified: a byte-for-byte copy of the published crate under vendor/gpui-pre-linux (without the registry's Cargo.toml.orig/.cargo-ok), wired in through [patch.crates-io] like crates/embed-resource and excluded from the workspace, so fmt/clippy keep their scope. vendor/README.md records the source revision (zed@bcf6582). Reviewers can check it with diff -r ~/.cargo/registry/src/*/gpui-pre-linux-0.3.6/src vendor/gpui-pre-linux/src.
2. build: skip vendored crates in the file-size check: GPUI's client.rs (3,223 lines) and window.rs (2,332) exceed the 1,000-line limit. Splitting them would make re-syncing with upstream impractical, so check-file-size.sh now skips vendor/. Code this project owns is checked as before. This relaxes a deliberate policy, so it needs your call. If you'd rather not vendor GPUI, I'll send the fix upstream only and close this.
3. fix: blur the translucent window on KDE Plasma 6.8 and newer KWin: the actual change (+34 lines in two files):
   • binds ext_background_effect_manager_v1 (from wayland-protocols 0.32.13, already in the lockfile with the staging feature, so no new dependency) and prefers it, with org_kde_kwin_blur as the fallback;
   • its blur region starts empty (KDE's covers the whole surface by default), so it is set to the same window-area region GPUI already computes for the opaque region; the region is double-buffered and applies with the next surface commit;
   • clearing blur or closing the window destroys the effect object, which removes the region on the next commit, and re-enabling creates a fresh one, so background_effect_exists cannot be raised.

The compositor's capabilities event is ignored, as GPUI already does for the KDE manager: if blur isn't offered, setting a region has no effect.

I'll send the same change upstream to zed-industries/zed. Once a gpui-pre release includes it, vendor/ and the patch entry can be dropped.

Screenshots

None. The change only affects KWin 6.8+ sessions and I'm on Hyprland, which blurs translucent surfaces without any protocol request. I have no KDE 6.8 desktop to capture before/after.

QA

• just ci on ca33d9c (Linux x86_64, Omarchy/Hyprland): fmt check, file-size, keep-sorted, and clippy -D warnings (all features and no default features) pass. Tests: 4,630 passed, 3 failed, 9 ignored in herdr-gpui, and every other crate passed. The 3 failures are host-dependent and fail identically on unmodified main (0ca50aa) on this machine, so they are unrelated to this change:

  • config::tests::loading::managed_headers_accept_lf_and_crlf_without_migrating_defaults and …local_overrides_merge_tables_replace_arrays_and_refresh_defaults read the desktop's real Omarchy theme state ("Omarchy" vs the expected "Default")
  • cloud::install::tests::the_probe_finds_herdr_where_the_bridge_looks finds the distro's /usr/bin/herdr, which isn't in the test's list of system roots that skip the assertion

  So this is not a fully green local run. I can send a separate fix that isolates those tests from the host if you want.

• cargo check --locked -p gpui-pre-linux builds the patched crate with no warnings

• Vendored copy is byte-identical to the published crate (diff -r against the cargo registry source)

• On KDE Plasma 6.8 Wayland with the blur effect enabled: set backdrop.opacity 0.85 and blur = true, put a detailed window behind Herdr UI, and confirm it shows through blurred

• Toggle Settings > Theme > Window between Translucent + blur and opaque a few times: blur turns off and on again, with no protocol error in the log

• On an older KWin that still offers org_kde_kwin_blur only: blur still works (fallback path)

• On Hyprland: no visible change (no protocol request is needed there)

[greptile-apps]

Confidence Score: 4/5

[Medium impact] The change reaches a specific Linux window-blur workflow.

Fix the missing vendored source in the Nix build before merging; the blur rectangle also needs a resize follow-up.

Findings

1.  Nix builds lose required source ▶
2.  Blur stops at old edges ▶

Summary

Vendors gpui-pre-linux 0.3.6 and adds standard Wayland background-effect requests, while retaining the older KDE blur fallback.

• Wayland windows blur the desktop through KWin's standard effect or its older KDE protocol.

Acknowledged choices: itsmunzir explicitly identifies the vendored file-size exemption as intentional and says compositor capabilities are intentionally ignored.

Review checks were static. No build, desktop session, or visual verification was run.

Diagram

%%{init: {'theme': 'neutral'}}%%
flowchart TD
  A[Window appearance changes] --> B{Standard manager available?}
  B -->|Yes| C{Blur requested?}
  C -->|Yes| D[Create effect if needed and set blur rectangle]
  C -->|No| E[Destroy existing effect]
  B -->|No| F[Use older KDE manager if available]
  D --> G[Next surface commit applies blur]
  E --> G
  F --> G

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_{Reviews (1) · Last reviewed commit: "fix: blur the translucent window on KDE ..." · Reviewed by Greptile}

[greptile-apps]

Nix builds lose required source

The new path patch requires vendor/gpui-pre-linux, but flake.nix copies an explicit list of source directories that leaves out vendor. Cargo cannot find vendor/gpui-pre-linux/Cargo.toml, so the Nix package fails before compilation. Add the vendored crate to the Nix source list alongside this patch.

[greptile-apps]

Blur stops at old edges

The new blur rectangle does not follow window size changes. Resizing updates the bounds without calling update_window, and rendering skips unchanged appearance and inset calls. Enlarging or maximizing a blurred window therefore leaves the added area unblurred.

Refresh the region when the size changes. Calculate it from the current surface bounds rather than window_bounds, which keeps the size used to restore a maximized window.