T20: on Wayland the window asks for ext_background_effect_v1 on its surface, through a guest connection on gpui's display; one region wider than any window, which the compositor clips, comes and goes with Blurred; the log names the way blur goes; a wayland-server compositor tests it, and scripts/linux.sh runs the tests on Linux in a container

AGENTS.md

@@ -8,6 +8,7 @@ ELYTerminal. A terminal on GPUI and Ely components. `PRD.md` says what it does;
 - Ely (`ely-gpui-component`) from git.zacharyzhang.com, pinned by rev. gpui and gpui_platform from crates.io's `gpui-pre`, the exact version Ely pins, under their crate names through `package`.
 - `alacritty_terminal` 0.26: grid, parser, pseudo-terminal, event loop.
 - `serde`, `serde_json`: settings. `dirs`: the config folder. `log`, `env_logger`: logs to stderr. `unicode-normalization`, on macOS: Git's marks in composed form.
+- On Linux, `wayland-client`, `wayland-backend` and `wayland-protocols` (staging) ask the compositor for `ext_background_effect_v1` on gpui's own connection; `wayland-server` hosts a compositor in the tests.
 
 ## Commands
 
@@ -19,10 +20,11 @@ ELYTerminal. A terminal on GPUI and Ely components. `PRD.md` says what it does;
   - `to:settings` and `to:main` aim the specs after them, and the picture, at that window, which becomes the app's key window, since AppKit sends keys there; the app stays inactive, and gpui sends an inactive window no focus or blur events, so press Enter to commit a field;
   - mouse gestures handed to gpui's view, at points from the content's top-left, modifiers as for keys: `click@x,y`, `click2@`, `click3@`, `rclick@`, `mclick@`, `drag@x,y@x,y`, `move@x,y`, the steps `ldown@`, `lup@`, `ldrag@`, `rdown@`, `rup@`, `mdown@`, `mup@`, and `scrollup@x,y@lines`, `scrolldown@x,y@lines`.
 - `scripts/check.sh`: fmt, clippy `-D warnings`, tests, the 500-line rule.
+- `scripts/linux.sh ARGS` runs `cargo ARGS` on the working tree in a Linux container, the build kept in Docker volumes; `scripts/linux.sh test --locked` runs the tests as a user, not root, as CI does. The tree goes in as a tar stream, every file dated now: Colima's shared folder can show the VM a file as it was before an edit, and cargo judges by date, so a tree older than the last build would reuse that build. It needs a Docker daemon: on macOS, Colima (`colima start`).
 
 ## Layout
 
-- `src/main.rs`: start. `src/lib.rs`: the modules, public so tests and examples reach them. `src/app.rs`: fonts, settings, integration, then the main window. `src/blur.rs`: what the window shows of the desktop, from the opacity and blur settings, set as they change. `src/workspace.rs`: the window's content, Ely's `ColumnShell` with the sessions, terminal and right columns, their toggles, the right column's Git and Files switch, the title, and the sessions' lifecycle. `src/sessions.rs`: a session and its row. `src/files.rs`: the Files panel, the shown session's folder as Ely's `Tree` with Git's marks. `src/git.rs`: git through its command line: Files' marks, and the Git panel's status, stage, unstage, discard, commit and log; `src/git/diff.rs` reads git's diff into Ely's stretches. `src/git/panel.rs`: the Git panel's state and actions; `src/git/panel/view.rs`: how it draws.
+- `src/main.rs`: start. `src/lib.rs`: the modules, public so tests and examples reach them. `src/app.rs`: fonts, settings, integration, then the main window. `src/blur.rs`: what the window shows of the desktop, from the opacity and blur settings, set as they change; `blur/wayland` asks a Wayland compositor for blur behind the window's surface through `ext_background_effect_v1`. `src/workspace.rs`: the window's content, Ely's `ColumnShell` with the sessions, terminal and right columns, their toggles, the right column's Git and Files switch, the title, and the sessions' lifecycle. `src/sessions.rs`: a session and its row. `src/files.rs`: the Files panel, the shown session's folder as Ely's `Tree` with Git's marks. `src/git.rs`: git through its command line: Files' marks, and the Git panel's status, stage, unstage, discard, commit and log; `src/git/diff.rs` reads git's diff into Ely's stretches. `src/git/panel.rs`: the Git panel's state and actions; `src/git/panel/view.rs`: how it draws.
 - `src/settings`: the model, its ranges, and `SettingsStore`, the global that loads, checks and saves `settings.json`; `window` is the settings window, `window/appearance` its Appearance page, `window/terminal` its Terminal page. `tests/fonts.rs` brings its own main: gpui builds its Mac platform only on the main thread.
 - `src/themes`: built-in terminal themes, the chrome palette each maps to, and `apply`, which dresses the app for the system's appearance.
 - `src/term`: the terminal engine. `pty` starts a program through alacritty's event loop; `tap` wraps the pty so its reader scans OSC 7 and the mouse modes before the parser. `unix` starts the program itself, so a failed `chdir` fails the start; Windows uses alacritty's ConPTY. `shell` writes the integration scripts at start and builds each shell's launch. `frame` reads the grid into styled rows, `boxes` turns box drawing, block elements and powerline arrows into rects and polygons (`boxes/outline` strokes curves and diagonals into polygons), `ink` resolves colors, `paint` draws rows, decorations and the cursor, `view` is the entity: pty events, metrics, blink, resize. `keys` turns key events into bytes, the kitty protocol and, in `keys/legacy`, xterm's encoding, with no gpui types; `input` is the view's key listeners, the bindings that keep Tab and F6 from Ely's focus moves, and its IME handler; `mac` reads the Option side and repeat flag of AppKit's current event, keeps held keys repeating, and hands Command key-ups to the focused view. `mouse` encodes mouse reports, with no gpui types; `links` finds the link at a cell; `pointer` is the view's mouse listeners: selection, reports, wheel, links, copy and paste. `find` is the find box: Ely's `FindWidget`, and Ely's `find_all` over the grid's shown text.
@@ -70,3 +72,4 @@ ELYTerminal. A terminal on GPUI and Ely components. `PRD.md` says what it does;
 - 2026-10-14: Appearance shows every built-in theme as Ely's `RadioCard` in a `SimpleGrid`, each over a small window in the theme's colors. Separate dark theme copies the theme into `dark_theme`, so turning it on changes nothing until a dark card is picked. A theme change re-dresses the chrome at once. Font family comes from Ely's `FontPicker`; size, line height and padding from its `NumberInput`, which saves a number on Enter, on leaving the field and on each step. A font saves, and a settings file starts, only when gpui loads it as the terminal draws it: gpui falls back to another font without a word and loads none without an `m`, so the terminal draws with no font but its own. The cursor preview is a prompt in the terminal's font and theme, its cursor drawn as the terminal draws it, blinking on the terminal's beat. Opacity moves by whole percents, so the saved fraction carries no float noise. Blur saves here and reaches the window in T19. A change the store refuses leaves the setting as it was, and the page says why at its top; a number field drops its draft, and the font picker shows the saved family again. The settings window opens at 900 by 640, room for three theme columns.
 - 2026-10-14: Terminal shows scrollback lines, Option as Alt, on macOS only, since elsewhere Alt is Alt, and copy on select. The engine reads each when it needs it, so a change applies at once to every session; a smaller scrollback drops the history past it.
 - 2026-10-14: the main window lets the desktop through while Background opacity is under 1, blurred or clear as Background blur says, through gpui's `Blurred` (macOS's NSVisualEffectView, Windows' acrylic) or `Transparent`; at 1 it is `Opaque`. The workspace sets it as the settings change. Ely's `ColumnShell::glass`, added to Ely for this, grounds the columns in the palette's glass, which the opacity sets, so the title bar and every column let the desktop through alike; the palette's `bg` stays solid, so a dialog, the Git diff among them, hides what lies under it. The terminal paints no ground over the glass, or the two would stack; a program's own background (OSC 11) paints over it. Ely's own themes pass their palette too, Ely's colors with the glass set. The settings window stays opaque.
+- 2026-10-15: on Wayland the window asks for `ext_background_effect_v1` beside gpui's `org_kde_kwin_blur`. A guest connection on gpui's own display binds it, takes the effect for the window's surface once, and sets a blur region of one rect wider and taller than any window, which the compositor clips to the surface, so a resize needs nothing; the region goes and comes back with Blurred and lands at the surface's next commit, which every frame makes. The guest connection reads the display only while the window opens, before gpui's loop runs, and is never dropped: a drop destroys its proxies through the display, which gpui may close first. The log names what the compositor offers, so which way blur goes: `ext_background_effect_v1`, gpui's `org_kde_kwin_blur`, or none, the desktop clear. Its test runs a `wayland-server` compositor on a socket pair.