komorebi/docs/dev/ARCHITECTURE.md

# Architecture

komorebi is a tiling window manager. It decides where every window goes and asks a
compositor to put it there. Everything it needs from the compositor is behind one trait,
[`Backend`](../../komorebi/src/backend/mod.rs), so the window manager is written, and
tested, without one.

This page describes that trait, who implements and calls it, where each of its rules is
enforced, the model of the desktop the window manager tiles, the backend that reaches KWin,
how an event about a window becomes a tile, how workspaces are the compositor's desktops, how
a stack hides its windows, how the window manager follows a monitor that changes, how a message
on the daemon's socket is answered, how subscribers are notified of all three, what the orders a
message gives do, what a drag with the pointer does, how the compositor is asked to draw the
borders, how `komorebi.json` configures the daemon, and how the NixOS module runs the daemon. It
grows with the code: each part of the daemon that is added has its place here.

## Vocabulary

- **Window**: a top-level surface a client has asked the compositor for, named by the
  compositor's `u32` id.
- **Monitor**: a connected output, with its bounds and its work area (its bounds minus
  the panels).
- **Wallpaper**: the picture a monitor shows while one of its workspaces is in front, and the theme
  made of it. A workspace's own wins over its monitor's.
- **Workspace**: the containers a monitor shows, in order, and the layout that tiles
  them. A monitor has a ring of workspaces and shows one of them. Workspace `i` is the
  compositor's desktop `i` on that monitor. A workspace can have a name, which the named
  commands find it by.
- **Desktop**: one of KWin's virtual desktops. KWin shows the windows of one desktop on each
  output and hides the others; with its per-output virtual desktops on, each output shows a
  desktop of its own.
- **Container**: what a layout places. It gets one tile, and every window in it is put on
  that tile.
- **Stack**: a container with more than one window. It has one tile, and the window in front
  (the container's focused window) is in sight; the others are hidden.
- **Hidden window**: a window of a stack that is not in front, or of a container a monocle
  leaves out, which komorebi has taken out of sight ([`Backend::hide`]) and recorded in
  [`HIDDEN_WINDOWS`]. It is alive, not minimized, and on its workspace.
- **Parking desktop**: the virtual desktop, named `komorebi-park`, that the KWin backend hides
  windows on. It is not a workspace.
- **Layout**: the arrangement (BSP, columns, rows, ...) that turns a work area and a
  number of containers into one rectangle, a **tile**, for each container.
- **Monocle**: a workspace's one container that has the whole work area. It is held out of the
  workspace's containers, so the layout gives no container a tile, and the windows of the
  containers are hidden, until it is put back where it was ([`Workspace::monocle_container`]).
- **Layer**: which of a workspace's two kinds of windows the focus, move and resize commands
  act on: its tiles (`Tiling`) or its floating windows (`Floating`) ([`WorkspaceLayer`]).
- **Maximized window**: a workspace's one window that the compositor has maximized. It is in no
  container, so it has left the layout, until it is put back in a container of its own where it
  was ([`Workspace::maximized_window`]).
- **Event**: what the compositor reports about a window: it was shown, destroyed, given
  the focus, minimized or restored, dragged by the user, or put on another workspace's desktop;
  and that a monitor shows another workspace ([`WindowManagerEvent`]). Two events come from
  komorebi itself: a command asks it to manage the focused window, or to stop managing it.
- **Message**: what a client sends the daemon on its socket, a [`SocketMessage`]: an order
  (focus a window, move it, change the layout, resize it, show a workspace, retile, stop) or a
  question (the state, the monitors, one [`StateQuery`]).
- **Configuration**: `komorebi.json`, which the daemon reads when it starts and again when it
  changes ([`StaticConfig`]). It lives in the **config home**, [`HOME_DIR`], unless `--config`
  names another.
- **Rule**: a condition on a window's title, executable, class or path ([`MatchingRule`]), in
  one of the process-wide lists that decide whether a window is managed (the ignore and the
  manage rules) and whether it floats when it opens (the float rules).
- **Direction**: where an order goes from the focused container: a side of its tile
  ([`OperationDirection`]), or the next or the previous container of the workspace
  ([`CycleDirection`]).
- **State**: the window manager's monitors, workspaces, containers and windows, and its
  settings, as the daemon answers a `State` message with them ([`State`]).
- **Subscriber**: a program that listens on a socket of its own in [`DATA_DIR`] and has
  asked the daemon, by the name of that socket, to send it notifications.
- **Monitor notification**: what the KWin backend sends the monitor reconciliator when the
  outputs change ([`MonitorNotification`]).
- **Notification**: what a subscriber is sent after each event, each message and each change
  of the monitors the window manager handles: the event, the message or the change, and the
  state after it ([`Notification`]).
- **Look**: how the compositor is asked to dress the windows, which it draws ([`Look`]):
  a border, with its width, its corner radius and two colors, and the animation of windows going
  to their places, with its duration and its easing curve.
- **Opacity**: how opaque a window is drawn, 0 to 255, a property of the window in the compositor,
  which [`transparency_manager`] sets for the windows that do not have the focus.
- **Effect**: a plugin of the compositor that changes how windows are drawn. KDE Rounded Corners
  is the effect that draws the border, and Geometry Change the one that animates windows.
- **Compositor**: the program that owns the screen and the windows. On KDE Plasma it is
  KWin.
- **Backend**: the implementation of the [`Backend`](../../komorebi/src/backend/mod.rs)
  trait that talks to a compositor.
- **Fake**: [`FakeBackend`](../../komorebi/src/backend/fake.rs), the in-memory backend
  the tests use.
- **Bridge**: the script komorebi loads into KWin ([`bridge.js`]). It reports what KWin
  tells it and carries out what the daemon asks.
- **Table**: the KWin backend's model of the desktop ([`Table`]), which the bridge's events
  keep up to date and the queries are answered from.
- **Held call**: the `Poll` call the bridge always has open, which the daemon answers when it
  has commands for the bridge, or after 10 seconds with none.
- **Module**: `services.komorebi`, the NixOS module ([`nixos-module.nix`]), which installs
  komorebi and runs the daemon in every Plasma session as the systemd user unit
  `komorebi.service`.

## Design

The window manager reads the desktop and changes it through [`Backend`] and through
nothing else. A real backend answers from a table that compositor events keep up to date,
and sends commands to the compositor. The fake answers from a table the test fills in, and
records the commands. The window manager cannot tell them apart, which is the point:
the same logic runs against both. The reasons are in
[DESIGN.md](DESIGN.md#why-is-everything-the-window-manager-needs-behind-one-trait).

## The model

The desktop, as the window manager sees it, is two lists and a pointer:

- **Windows**, each a [`WindowInfo`]: its id, process, title, `app_id`, executable, frame,
  whether it is minimized, whether it is a normal application window (as opposed to a
  dialog, a splash screen or a dock), and whether it is alive. A window that has been
  destroyed stays in the table for a short time with `alive` false, so that the event that
  mentions it can still be logged.
- **Monitors**, each a [`MonitorInfo`]: its id, name, an identity that survives a
  hot-plug, its bounds and its work area.
- **The pointer**, a position if the compositor says where it is, and the **focus**, the id
  of the window that has it.

A command is one of: move and resize a window, focus it, raise it, hide it or restore it,
minimize it or bring it back, maximize it or unmaximize it, close it, put the pointer in the
middle of a rectangle, make desktops for the workspaces, show a workspace on a monitor, and put
a window on a workspace. The workspace a window is on, and the one each monitor shows, are
queries.

The window manager tiles a tree of four levels, each level a [`Ring`]: a list with one
element focused, so that "the focused workspace" or "the focused container" means
the same thing at every level.

- A **monitor** ([`Monitor`]) is one of the backend's monitors: its bounds, its work area,
  its padding, an optional work area offset, an optional window-based offset with the number of
  windows up to which it applies, and its workspaces. It shows the focused one.
- A **workspace** ([`Workspace`]) has a layout, its padding, an optional work area offset of its
  own, whether it takes the monitor's window-based offset, its containers, in order, its
  monocle container and its maximized window, if it has them, and its floating windows, which
  are in no container and which the layout does not tile, and which layer it is on.
- A **container** ([`Container`]) has its windows. A new window gets a container of its
  own, unless the window container behavior says to put it in the focused one. With more than
  one window it is a stack: the focused window is in front and the others are hidden. A
  container can be locked, which keeps it at its index while others are inserted, removed or
  swapped around it.
- A **window** ([`Window`]) is a `Copy` handle that carries only the compositor's id.
  Everything else about the window, and every change to it, goes through the backend.

Tiling a workspace ([`Workspace::update`]) is a function of this tree and a work area. The
monitor gives its focused workspace the work area, the padding to fall back to, the offset
(its own, or else the window manager's) and its window-based offset ([`WorkspaceGlobals`]).
The workspace takes the offset (its own, or else the monitor's) off the work area, then the
window-based offset while it has no more containers than the monitor's limit, then its
padding; the layout gives one tile per container, in order, each shrunk by the container
padding, and every window of a container is asked to move onto its tile with `set_rect`. A
tile is clamped to the work area, so it cannot reach onto a neighboring monitor.

The [`WindowManager`] keeps the monitors, the windows the user minimized (they are in no
workspace until they are restored), and an index from each window it manages to the
monitor and workspace that have it. It is loaded from the backend at startup: every
monitor, focused on the workspace the compositor shows on it, and every open window that is
normal, alive, not minimized and not ignored by a rule, on the workspace whose desktop it is
on, of the monitor its middle is on. After that it changes only when an event comes in, and
each event ends with the workspace in front tiled again.

## The KWin backend

[`KWinBackend`] is the backend of a real Plasma session. KWin has no protocol that lets
another process read and set window geometry, so the backend is in two processes:

- **The bridge**, [`bridge.js`], a script KWin runs inside itself. It subscribes to KWin's
  signals and sends each as a JSON `Event` call over the session bus, and it carries out the
  commands it gets as the answer to its held `Poll` call. When it starts it sends a snapshot
  of the desktop. It holds no window manager logic.
- **The daemon's side**, [`kwin`], owns `org.komorebi.Bridge` on the session bus, with one
  object for `Event` and one for `Poll`. `Event` calls are handled one at a time, in the order
  they arrive, and never wait. A `Poll` call is held until there are commands, so that the
  bridge gets them as soon as they are queued, without a timer and without a call from the
  daemon into KWin.

Every decision about what an event means is made in the daemon, by the table
([`kwin::state`]): an event goes in, the table is updated, and what follows comes out, a
window event for the window manager or the answer to a query. The table is pure (no D-Bus,
no threads), so the unit tests drive it with the JSON the bridge sends.

The bridge is JavaScript, which no Rust build compiles, and KWin loads the file as it is, so
it is checked without a build step. `tsc` checks it as strict TypeScript through its JSDoc
comments, which type every message, against [`kwin-api.d.ts`], the part of KWin's scripting
API the bridge uses. [`bridge.test.js`] runs it with `node --test` against a fake of that API.
The two sides share the messages of a session in [`fixtures`]: the bridge's tests check that
it sends exactly those events, and answer it with those commands, and the Rust tests feed
the events to the table and check that the backend sends those commands. A change to a
message on one side fails a test on the other.

The path of an event: a KWin signal, the bridge's handler, `Event(json)` on the session bus,
[`Table::handle`], a [`WindowManagerEvent`] on the channel of
[`window_manager_event_listener`], the thread that [`listen_for_events`] starts, and
[`WindowManager::process_event`]. The queries (`windows`, `window`, `foreground_window`,
`monitors`) are answered from the table. `cursor_pos` is the exception: only the bridge can
read the pointer, so it is asked through the held call, and given 250 ms to answer before
the table's last known position is returned.

A command goes the other way. The backend looks up the UUID KWin knows the window by,
queues a JSON command for the bridge, and returns. The held `Poll` call is answered with the
queue, as one batch: the daemon waits a millisecond after the first command for the rest, so
that a retile of every window of a workspace reaches KWin at once. The bridge carries the
commands out in order and reports the ones it could not carry out (a window that closed in
the meantime) as a `failed` event, which is logged. `set_rect` also records the frame it
asked for in the table, so that the window manager sees it straight away; the `geometry`
event that follows says what the client made of it. The pointer cannot be moved from a
script: when it follows the focus, the backend invokes KWin's "Move Mouse to Focus" shortcut,
which centers it on the window KWin has focused. When komorebi stops, the backend asks KWin to
unload the bridge.

KWin can restart under a running daemon, on the same session bus. The thread that serves
the connection watches the owner of `org.kde.KWin` on the bus. When KWin leaves it, the
bridge has gone with it and its windows too, and nothing will report them closing:
[`Table::compositor_lost`] marks every window closed and returns a `Destroy` for each, so the
window manager takes them out of its layout. When KWin is back, the daemon loads the bridge
into it again, the bridge sends a snapshot of the new KWin's desktop, and its events are
handled as before. The `Poll` call the old bridge held is still open in the daemon, since
zbus does not end a call when its caller leaves the bus: it is answered with nothing as soon
as it wakes, and the commands go to the new bridge's call.

[`connect`] makes the backend: it connects to the session bus, loads the bridge into KWin,
and returns once the snapshot has arrived, so that the window manager reads a full table when
it starts. [PLATFORM.md](PLATFORM.md) has the D-Bus names, the files and the environment
variables; [DESIGN.md](DESIGN.md#why-does-komorebi-run-a-script-inside-kwin) has the reasons.

## Workspaces

komorebi's workspaces are the compositor's virtual desktops: workspace `i` is desktop `i` on
every monitor, and each monitor shows one at a time. The compositor shows the windows of the
desktop in front, hides the others, and keeps which window of each desktop had the focus; the
window manager hides no window to leave a workspace. The reasons are in
[DESIGN.md](DESIGN.md#why-are-komorebis-workspaces-kwins-virtual-desktops).

Showing a workspace ([`Monitor::load_focused_workspace`]) is three steps. Every window of every
workspace of the monitor is put on the desktop of its workspace, unless it is already there.
The compositor is asked to show the workspace on the monitor ([`Backend::switch_workspace`]),
which leaves the other monitors as they are. The workspace's focused window is given the focus.
The order matters: a window that is focused while it is on another desktop takes the monitor
back to that desktop.

Desktops are global in KWin: every monitor has as many as the monitor with the most
workspaces, and each has one name. At startup, and when a workspace is asked for that has no
desktop, the backend creates the missing ones over KWin's `org.kde.KWin.VirtualDesktopManager`
interface, named "Workspace 1", "Workspace 2" and so on ([`WindowManager::sync_workspace_desktops`]).
Without KWin's per-output virtual desktops every output would show the same desktop, so
[`connect`] turns them on in the user's `kwinrc`, and [`Kwinrc`] keeps the user's value and
puts it back when komorebi stops, also after a crash.

Something else can switch a monitor to another desktop: a pager, a KWin shortcut, an
application that raises a window of another desktop, which KWin answers by showing that
desktop. KWin has one signal for it, which does not say which output, so the bridge sends the
desktop of every output after it, and once a second. The table compares it with what it had,
and a monitor that shows another desktop is a `WorkspaceChange` event: the window manager
focuses that workspace and tiles it ([`WindowManager::adopt_workspace_change`]), and asks the
compositor for nothing, since KWin has already shown the windows and chosen which to focus. A
window put on another desktop by something else (the window menu's "Move to Desktop") is a
`WorkspaceMove`: the window manager moves the window to that workspace. komorebi's own switch
and move come back from KWin as the same reports; the table records them when the command is
sent ([`Table::switch_commands`], [`Table::window_workspace_commands`]), so they raise nothing.

## Stacks

A container has one tile, so when it has more than one window the others have to be out of
sight, and out of the way of the pointer and the focus: the window manager hides them
([`Window::hide`]). Minimizing them would not do. KWin reports a minimize as the user's, and
the windows would be taken for ones the user does not want tiled. What komorebi uses is the one
thing KWin has that hides a window and leaves it alone: a virtual desktop nobody looks at, the
parking desktop. The reasons are in
[DESIGN.md](DESIGN.md#why-are-the-windows-behind-the-front-one-of-a-stack-moved-to-a-parking-desktop).

A container keeps its front window in sync with what is in sight ([`Container::add_window`],
[`Container::load_focused_window`]): the window that is added or focused is shown, and every
other one is hidden. Operations that change which window is in front, or which container a
window is in, end with that call: stacking and unstacking ([`Workspace::move_window_to_container`],
[`Workspace::new_container_for_focused_window`]), a window that closes
([`Workspace::remove_window`], which brings the next one forward and focuses it), a window that
is floated, a focus change to a window that is behind ([`Workspace::focus_container_by_window`]),
and cycling the stack or focusing a window of it by its index.

A monocle hides the other containers in the same way. Turning it on hides every window of each
of them ([`Container::hide`]), turning it off restores the window in front of each
([`Container::restore`]), and cycling it hides the container it gave up. While a monocle is on,
[`Workspace::restore`] restores its window and no other, and [`Workspace::hide`] hides it with
the rest.

[`Window::hide`] puts the window's id in [`HIDDEN_WINDOWS`] before it asks the backend, and
[`Window::restore`] takes it out, so that when the compositor reports something about the window
because of the hide the window manager knows who did it. A `Minimize` for a window in the set is
not the user's and changes nothing. On the way out, [`WindowManager::stop`] and the daemon's
`SIGINT` and `SIGTERM` handler restore every window in the set before the backend shuts down
([`WindowManager::restore_all_windows`]).

The KWin backend hides a window by putting it on the parking desktop. The table keeps for each
window whether it is parked and the desktop it came from ([`Table::hide_commands`],
[`Table::restore_commands`]): a hidden window is still on its workspace for every query
([`Table::window_workspace`]), a window put on another workspace while it is hidden is hidden
still and comes back there ([`Table::window_workspace_commands`]), and KWin's report that the
window moved to the parking desktop is not a `WorkspaceMove`. The parking desktop is made the
first time it is needed ([`NeedsPark`], `create_park_desktop` in [`kwin`]), by position, so
that it stays after the workspaces' desktops. The table checks that KWin still lists it before it
sends a window there, and asks for a new one when somebody removed it.

An application that raises a hidden window, or a click on it in the task manager, makes KWin
switch that monitor to the parking desktop. The table notices that a monitor shows it, sends the
monitor back to the desktop it showed before, and raises no `WorkspaceChange`; the window's own
`FocusChange` then brings it to the front of its stack.

KWin keeps its virtual desktops in `kwinrc` as soon as one is made, so a parking desktop that
komorebi does not remove stays for every later session. The backend removes it in `shutdown`,
after the restoring commands have reached the bridge. A daemon that was killed leaves it, with
windows on it: the first snapshot the next daemon gets lists a desktop with that name, which the
table treats as stale ([`Table::stale_park`]). It is never the parking desktop of the new run.
The snapshot sends the windows on it to the first workspace's desktop, and half a second later
the backend removes it (`sweep_stale_park`).

## Monitors that change

The outputs KWin has change under a running daemon: an output gets another resolution or
scale, or a panel changes the room the windows have on it. KWin has one signal for the outputs
(`workspace.screensChanged`) and none for the room a panel leaves, so the bridge sends every
output, with its geometry and work area, as a `screens` event when the signal comes, when a
dock window opens, closes or moves, and once a second, each time the outputs are not what it
last sent. The table compares them with the monitors it had ([`Table::handle`]), and a monitor
whose size or work area changed is a [`MonitorNotification::Resize`]. It is not a window
event, since it is about no window, and it goes to the monitor reconciliator
([`monitor_reconciliator`]), not to the window manager's channel of events.

The reconciliator is a thread with a channel of its own ([`listen_for_notifications`]). It takes
one notification at a time with the window manager locked, as the thread of events and the
thread of messages do, so the three never change the window manager at once. For a `Resize` it
reads the size and the work area of every monitor from the backend again
([`update_monitor_work_areas`]), tiles the workspace in front of the focused monitor in the area
it has now, and notifies the subscribers ([`NotificationEvent::Monitor`]). Another monitor's
windows keep their tiles until something tiles them again, such as `Retile`.

A monitor that is unplugged or plugged in changes the set of outputs, and the table announces
that as a [`MonitorNotification::DisplayConnectionChange`], by the ids of the monitors. KWin has
already taken the windows of the output that went to the outputs that are left, so komorebi's
tiles for them are on a screen that is gone and the windows sit untiled where they landed. The
reconciliator ([`reconcile_display_change`]) reads the monitors from the backend and compares
them with the window manager's by their serial number ids. For each monitor that went it keeps a
copy, with its workspaces and settings, in a cache that lives as long as the daemon
([`insert_in_monitor_cache`]), and has the window manager move what was on it to the monitors
that are left ([`WindowManager::evacuate_monitor`]). Each container and floating window goes to
the workspace of the same number on the monitor that now holds the middle of its window's frame,
or on the first monitor that is left when the window is on none; a stack goes as the container it
is, and a monocle and a maximized window come as ordinary containers. The monitor is then removed.
A monitor that is new to the window manager is added by [`load_monitor_information`], and when
the cache has a monitor with its serial number id, the new monitor takes the cached workspaces and
settings, less the windows that have closed or that the window manager has elsewhere now, and the
cache entry is used once. Every monitor then shows the workspace in front again. The
focused monitor and workspace are focused again, since adding a monitor can take the focus. When
KWin reports no output at all, nothing is done.

A monitor that goes takes its workspace rules (the entries of [`WORKSPACE_MATCHING_RULES`] that
name its index) out of the list, and those of the workspaces a cached monitor brings back are
added again. The configuration fills the cache as well: [`StaticConfig::postload`] and
[`StaticConfig::reload`] keep a copy of each monitor that has the entry its display index
preference names, and make a monitor from the entry of each preference whose monitor is not
connected, so that the monitor takes its entry when it is plugged in.

## The command socket

The daemon takes messages on a Unix socket, `komorebi.sock` in [`DATA_DIR`]
(`$XDG_RUNTIME_DIR/komorebi`, or the local data directory without a runtime directory).
[`WindowManager::new`] binds it, after it removes a socket file that a daemon that did not
stop cleanly left behind, and the window manager keeps the listener. The daemon connects to
KWin before it makes the window manager, so a komorebi that cannot connect, such as a second
one in the same session, whose bus refuses it `org.komorebi.Bridge`, exits before it touches
the socket of the one that is running.

[`listen_for_commands`] starts a thread that accepts connections, and reads each connection
on a separate thread ([`read_commands_uds`]). A connection carries one [`SocketMessage`]
per line, as JSON with the variant's name in `type` and its arguments in `content`:
`{"type":"Query","content":"FocusedWorkspaceIndex"}`. Each message is handled by
[`WindowManager::process_command`] with the window manager locked, so messages are handled
one at a time. A message that waited a second for the lock is logged and dropped.

A question is answered on the same connection: the [`State`] or the monitors as JSON, or
the answer to a [`StateQuery`] as one value in plain text. The answer has no framing; it
ends when the daemon closes the connection, which it does once it has read the last line.
A client therefore shuts down its side for writing after its message, and reads until the
end ([`send_query`]). An order is answered with nothing, and a client that sends only
orders can close the connection as soon as it has written them ([`send_message`],
[`send_batch`]).

A message that fails (a query about the focused container when the workspace has none) is
logged, and the lines after it on that connection are not read. The client sees the
connection close with no answer.

`Stop` ends the daemon: [`WindowManager::stop`] removes the socket, lets the backend give up
what it set up in the compositor (the KWin backend unloads the bridge), and exits with
status 0. `SIGINT` and `SIGTERM` do the same from `main.rs`, with the exit status 130.

## Notifications

A subscriber binds a socket in [`DATA_DIR`] and sends `AddSubscriberSocket` with its name,
or `AddSubscriberSocketWithOptions` with its name and [`SubscribeOptions`]
([`subscribe`], [`subscribe_with_options`], `komorebic subscribe-socket`).
[`WindowManager::process_command`] records it in [`SUBSCRIPTION_SOCKETS`], and its options in
[`SUBSCRIPTION_SOCKET_OPTIONS`]. `RemoveSubscriberSocket` takes it out again. The
subscribers are kept in memory only, and a daemon that restarts has none.

At the end of [`WindowManager::process_event`] and of [`WindowManager::process_command`], and
after the monitor reconciliator has handled a notification, the window manager calls
[`notify_subscribers`] with a [`Notification`]: the event, the message or the change of the
monitors ([`NotificationEvent`]), and the [`State`] after it. A [`State`] made before the event
or the message is compared with the window manager after it ([`State::has_been_modified`]);
the monitors are compared down to the windows, and a window by its id only. An event about a
window komorebi does not manage, and a message that fails, return before this and are not
notified.

[`notify_subscribers`] serializes the notification once, and for each subscriber connects to
its socket, writes the JSON and closes the connection, all on the thread that handled the
event or the message, with the window manager still locked. A subscriber with
`filter_state_changes` is skipped when the state did not change, unless the notification is
about a window being shown, a subscriber being added, a change of the monitors, a theme being
set (the colors of the borders are not part of the state) or the configuration being reloaded.
A subscriber that cannot be connected to is removed, with its socket file, after the loop.
Writing to a subscriber that was connected to has no timeout, and a failed write returns an
error from the call that handled the event or the message. A subscriber that stops reading
therefore holds the window manager, and with it the thread that handles events: the backend's
events wait in the channel of [`window_manager_event_listener`], and past 20 the backend drops
them.

When the daemon stops ([`WindowManager::stop`], or `SIGINT` and `SIGTERM` in `main.rs`), it
connects to each subscriber and shuts the connection down without writing anything.

## Commands

A message that gives an order is a call to a method of the [`WindowManager`] from
[`WindowManager::process_command`]. An order that goes somewhere takes one of two kinds of
direction, both from `komorebi-layouts`:

- An [`OperationDirection`] (left, right, up, down) is a side of the focused container's tile.
  The workspace asks its layout which container is on that side
  ([`Workspace::new_idx_for_direction`]). A layout answers from the index of the focused
  container and the number of containers, not from where the windows are.
- A [`CycleDirection`] (next, previous) follows the order of the workspace's containers, and
  wraps around at both ends ([`Workspace::new_idx_for_cycle_direction`]).

`FocusWindow` and `CycleFocusWindow` focus another container of the focused workspace and give
its window the focus with the backend's `focus` ([`WindowManager::focus_container_in_direction`],
[`WindowManager::focus_container_in_cycle_direction`]). They retile nothing. When there is no
container in that direction, the focus goes to the monitor in that direction
([`WindowManager::monitor_idx_in_direction`], from the bounds of the monitors), to its container
nearest the monitor the focus came from (the leftmost one going right); with no monitor there
either, the message fails and changes nothing. Whether the pointer follows
the focus is [`WindowManager::mouse_follows_focus`], which `MouseFollowsFocus` and
`ToggleMouseFollowsFocus` set.

`MoveWindow` and `CycleMoveWindow` swap the focused container with the container in that
direction ([`WindowManager::move_container_in_direction`],
[`WindowManager::move_container_in_cycle_direction`]), and tile the workspace again: the window
that moved takes the other's tile, keeps the focus, and the pointer follows it. The swap goes
through `LockableSequence`, so a lock stays with its index: the container swapped onto a locked
index is locked in its place. When there is no container in that direction, the container goes
to the monitor in that direction ([`WindowManager::move_container_to_monitor`]), and
[`WindowManager::cross_monitor_move_behaviour`] says what it does there: by default (`Swap`) the
container at that edge of the other monitor comes back in its place, `Insert` puts it in among
the containers there, and `NoOp` keeps it where it is. With no monitor in that direction, the
message fails and nothing moves. [`WindowManager::cross_boundary_behaviour`] can make both cross
to the next workspace of the same monitor instead.

`ChangeLayout` and `CycleLayout` set the focused workspace's [`Layout`], and `FlipLayout`
mirrors it along an axis, on top of the flip it has ([`Workspace::layout_flip`]); each tiles
the workspace again ([`WindowManager::change_workspace_layout_default`],
[`WindowManager::cycle_layout`], [`WindowManager::flip_layout`]). A flip mirrors the tiles,
not the order of the containers, and a direction is flipped with them, so `focus left` on a
flipped layout goes to the tile on the left. `ToggleTiling` turns the workspace's tiling off
and on ([`Workspace::tile`]): with it off, [`Workspace::update`] moves no window, the workspace
still takes the windows that open into containers, and they are tiled when it is turned on.

`LayoutRatios` and `ScrollingLayoutColumns` set the focused workspace's [`LayoutOptions`]
([`Workspace::layout_options`]): the share of the work area its first columns and rows take, and
the number of columns of the scrolling layout in view. The layout calculates the tiles from
them, and from the tiles it calculated last ([`Workspace::latest_layout`]), which the scrolling
layout scrolls from.

The scrolling layout is a strip of columns that runs past the edges of the work area. Its tiles
are the only ones [`Workspace::update`] does not clamp to the work area, so the windows of the
columns out of view are off the screen; a window whose tile is out of view while part of it is
in view is centered in the work area first. A `FocusChange` tiles a scrolling workspace after the
focused container has changed, which scrolls the strip to it. KWin keeps part of a window it
resizes on an output, so the bridge asks again for the position of a window KWin pulled back
within a second of the command, three times at most ([`bridge.js`]'s `settle`), unless the window
is maximized meanwhile.

`Promote` moves the focused container to index 0, the largest tile of every layout but the grid,
through `LockableSequence`, so the containers before it move one index on
([`WindowManager::promote_container_to_front`]). `PromoteSwap` swaps it with the container at
index 0 and records the index it came from in [`Workspace::promotion_swap_container_idx`], so
that from index 0 it swaps back ([`WindowManager::promote_container_swap`]). `PromoteFocus`
focuses the container at index 0 ([`WindowManager::promote_focus_to_front`]), and
`PromoteWindow` focuses the container in a direction and promotes it. On the grid layout they
change nothing.

`ToggleFloat` takes the window the compositor has focused out of its container into the
workspace's floating windows, and back into a container of its own at the focused index
([`WindowManager::toggle_float`]). A floating window is in the index of managed windows like
any other, so its events find it, and [`Workspace::update`] leaves it where it is. Where a
floated window goes is [`WindowManagementBehaviour::toggle_float_placement`]: by default it
stays where it is.

`StackWindow` puts the focused window and the window of the container in a direction in one
container ([`WindowManager::add_window_to_container`]): the focused window goes to the front of
that container, or, when the focused container is a stack and the other is not, the other
container's window goes into the stack. `UnstackWindow` takes the front window out of a stack
into a container of its own after it ([`WindowManager::remove_window_from_container`]), `StackAll`
puts every window of the workspace in one container ([`WindowManager::stack_all`]), and
`UnstackAll` takes them out again ([`WindowManager::unstack_all`]). Each ends with the workspace
tiled again, and the window that was in front has the focus.

`CycleStack` brings the next or the previous window of the focused container to the front, which
wraps around ([`WindowManager::cycle_container_window_in_direction`]), and `FocusStackWindow` the
window at an index ([`WindowManager::focus_container_window`]). Both show that window, hide the
one that was in front ([`Container::load_focused_window`]) and give the window the focus.
`FocusStackWindow` first focuses the monitor the pointer is on, so that a program such as a bar
that runs it for a click on its own monitor acts there. `CycleStackIndex` swaps the front window
with the next or the previous one in the container's order, and keeps it in front
([`WindowManager::cycle_container_window_index_in_direction`]): only the order of the stack
changes. A container of one window cannot be cycled, and an index it does not have cannot be
focused.

A window that opens gets the behavior [`WindowManager::window_management_behaviour`] says for
its workspace: a container of its own (`Create`, the default), or a place in the focused
container (`Append`), and a floating window with the float override on. A workspace's own
[`Workspace::window_container_behaviour`] and [`Workspace::float_override`] win over the window
manager's, and `Append` on an empty workspace is `Create`. `ToggleWindowContainerBehaviour` and
`ToggleFloatOverride` flip the window manager's, and `ToggleWorkspaceWindowContainerBehaviour` and
`ToggleWorkspaceFloatOverride` the focused workspace's, which starts from the opposite of the
window manager's value the first time.

`ToggleMonocle` takes the focused container out of the workspace's containers and makes it the
monocle container, which [`Workspace::update`] puts on the whole work area, less the padding, and
hides the windows of the other containers; turned off, their windows are restored and the
container is put back at the index it came from ([`WindowManager::toggle_monocle`],
[`Workspace::new_monocle_container`], [`Workspace::reintegrate_monocle_container`]). The container's resize adjustment is kept
meanwhile, and so is the whole of [`Workspace::resize_dimensions`], so that the tiles come back
as they were resized. While there is a monocle container, the window in front of it is the one
that has the focus: a `FocusChange` to another window gives the focus back to it, and
[`WindowManager::update_focused_workspace`] focuses it, not the focused container's window, which
is one of the tiles behind. `MoveWindow` and `CycleMoveWindow` are refused, and `ToggleFloat` is
ignored, for the focused container is not the window in front. What `FocusWindow` does is
[`WindowManager::monocle_focus_behaviour`]: with `Cycle`, it makes the next or the previous
container the monocle ([`WindowManager::cycle_monocle`]); with `NoOp`, the default, there is no
container on any side, so the focus goes to the monitor on that side, and it fails where there
is none. `CycleFocusWindow` always carries the monocle to the next or the previous container.
`MonocleFocusBehaviour` sets the behavior, and `ToggleMonocleFocusBehaviour` switches it. A focus
that crosses to a monitor whose workspace has a monocle container gives the focus to its window,
and a container moved to a workspace with one turns that monocle off first.

`ToggleMaximize` takes the focused window out of its container, and the container with it when
it was the last window in it, remembers the index, and asks the backend to maximize it: KWin's
own maximize, to the work area with the panels left alone ([`WindowManager::toggle_maximize`],
[`Workspace::new_maximized_window`]). From then on the workspace has a maximized window, in no
container, and [`Workspace::update`] asks the backend to maximize it again and moves nothing
else, so the containers stay where they were behind it. Toggled again, the window is restored
(the backend gives it back the frame it had), put in a container of its own at the index it came
from, and the workspace is tiled again ([`Workspace::reintegrate_maximized_window`]). A window in
monocle that is maximized leaves the monocle. While a window is maximized, the messages that are
about the tiles are dropped before they are handled: `MoveWindow`, `CycleMoveWindow`, the stack
messages, the resize, promote and preselect messages, `ToggleLock`, `ToggleFloat`,
`ToggleMonocle`, and the messages that send a container to another monitor or workspace
(`is_layout_command` in [`process_command`](../../komorebi/src/process_command.rs)). A window that
closes while it is maximized leaves the workspace like any other. `FocusWindow` finds no
container on any side of the maximized window, so the focus goes to the monitor on that side and
fails where there is none, and a maximized window, or a monocle, on the workspace it reaches is
given the focus whole. `CycleFocusWindow` is not dropped: it gives the focus to the next
container's window (the code has a TODO for what it should do). A maximized window is hidden
with the rest of its workspace, and restored and focused ahead of the containers' windows when
the workspace is shown again ([`Workspace::hide`], [`Workspace::restore`]).

A workspace is on one of two layers ([`Workspace::layer`]), and the focus, move and resize
messages go to the windows of that layer. `ToggleFloat` puts the workspace on the floating layer,
and putting the window back, or a `FocusChange` to a window that is not floating, a new tiled
window or a focus message that reaches a container, puts it on the tiling layer, which is where
a workspace starts; a `FocusChange` to a floating window, and a window that a float rule floats
when it opens, put it on the floating layer. `ToggleWorkspaceLayer` switches it by hand and raises
the windows of the layer it goes to, the focused one last, and gives the focus to one of them.
On the floating layer `FocusWindow` gives the focus to the nearest floating window on that side
of the focused one, by where the compositor has them, and where there is none the focus crosses
as it does for tiles, to the monitor on that side, and fails where there is none
([`WindowManager::focus_floating_window_in_direction`]); `CycleFocusWindow` goes round the
floating windows in the order they were floated
([`WindowManager::focus_floating_window_in_cycle_direction`]); `MoveWindow` moves the focused
floating window by [`WindowManager::resize_delta`], not out of the work area of the monitor
([`WindowManager::move_floating_window_in_direction`]); the resize messages change its frame,
and nothing is tiled ([`WindowManager::resize_window`]); and `PreselectDirection` does nothing.
`ToggleMaximize` maximizes the focused floating window there, which then leaves the floating
windows. `ToggleWorkspaceLayer` hides the floating windows when it goes to the tiling layer, and
shows them when it goes to the floating layer. A window that opens while the workspace is on its floating layer floats
(`floating_layer_override`) when the floating layer behaviour says to float: the workspace's own
([`Workspace::floating_layer_behaviour`]), else its monitor's, else the window manager's
([`WindowManager::window_management_behaviour`]). All three tile by default, and nothing sets
the first two until the configuration does.

`ToggleLock` locks the focused container, or unlocks it ([`WindowManager::toggle_lock`]), and
`LockMonitorWorkspaceContainer` and `UnlockMonitorWorkspaceContainer` do the same for a
container given by its indices. A lock changes nothing until containers are inserted, removed or
swapped around it, which the workspace does through `LockableSequence`.

`Minimize` and `Close` ask the backend to minimize or close the window the compositor has
focused, and change nothing else: the window leaves the layout when the compositor reports it,
through the `Minimize` and `Destroy` events. `UnmanageFocusedWindow` and `ManageFocusedWindow`
do not change the model either: they raise an `Unmanage` or a `Manage` event for the focused
window on the channel the backend's events go through
([`WindowManager::unmanage_focused_window`], [`WindowManager::manage_focused_window`]), and
the window manager handles them in order with the compositor's. An `Unmanage` is handled like a
`Destroy` of a window that stays open: the window leaves its workspace, is centered in the work
area, and its id goes into a list of unmanaged windows that `handle_event` checks before it acts
on any other event about a window; a `Manage` takes the id out of the list and is handled like a
`Show`. A `Destroy` takes the id out of the list too.

Whether a window is managed is [`Window::should_manage`]: the window has to be alive and normal,
and then the rules decide ([`should_act`]). An ignore rule that matches keeps the window out
unless a manage rule matches it too. The float rules do not decide whether a window is managed,
but a `Show` puts a window one matches in the workspace's floating windows instead of a container
(a `Manage` does not ask them). The rules live in process-wide lists in `lib.rs`:
`IgnoreRule` and `ManageRule` add a rule that names an application by one of the four
([`ApplicationIdentifier`]), and take the windows that it names exactly out of the containers of
the workspaces in front; `SessionFloatRule` adds a float rule made of the focused window's
executable, title and class, all three to be equal, and floats it, and `ClearSessionFloatRules`
takes those rules out again. `GlobalState` answers with the ignore and the manage rules
([`GlobalState`]), and `DebugWindow` with what [`Window::should_manage`] read of a window and
which rules matched ([`RuleDebug`]). A rule decides when a window is shown; the bridge reports
a title change (`caption`), which is a `TitleUpdate` event, and a `TitleUpdate` about a window
the index does not have, and that is not minimized, is sent again as a `Show`, so that a rule
about the title it has now decides.

`TogglePause` sets [`WindowManager::is_paused`]: while it is set, `handle_event` returns at once
for every event, and [`read_commands_uds`] hands only `TogglePause`, `State`, `GlobalState` and
`Stop` to the window manager. `UnmanagedWindowOperationBehaviour` sets
[`WindowManager::unmanaged_window_operation_behaviour`]: with `NoOp`,
[`WindowManager::process_command`] refuses every message while the window the compositor has
focused is in no container of the focused workspace
([`WindowManager::handle_unmanaged_window_behaviour`]).

`WorkspacePadding`, `ContainerPadding` and their `FocusedWorkspace` forms set a workspace's own
padding, and `NamedWorkspacePadding` and `NamedWorkspaceContainerPadding` do the same for the
workspace with a name, which they look up like `NamedWorkspaceLayout` does
([`WindowManager::monitor_workspace_index_by_name`]). `AdjustWorkspacePadding` and
`AdjustContainerPadding` change the focused workspace's by a number of pixels, which needs a padding
of its own to change ([`WindowManager::adjust_workspace_padding`]). `WorkAreaOffset`,
`MonitorWorkAreaOffset` and `WorkspaceWorkAreaOffset` set the offset of the window manager, of a
monitor or of a workspace, and `ToggleWindowBasedWorkAreaOffset` sets whether the focused workspace
takes its monitor's window-based offset ([`Workspace::apply_window_based_work_area_offset`]). Each
tiles the workspace in front again, or every monitor.

`ResizeWindowEdge` and `ResizeWindowAxis` resize the focused container
([`WindowManager::resize_window`]). A resize is an adjustment of the container's tile, kept in
[`Workspace::resize_dimensions`], one per container, which the layout applies when it calculates
the tiles; before every tiling, the workspace clears the parts of each adjustment that its layout
cannot apply, such as the top and the bottom of a column. The adjustment is the one
`komorebi-layouts` gives for the edge and [`WindowManager::resize_delta`], cut down until no tile
would be smaller than a tenth of the work area, or than it is already. The adjustments are kept
until a `Retile`, which drops them; `RetileWithResizeDimensions` tiles with them, and `Save`,
`Load`, `QuickSave` and `QuickLoad` write them to a file as JSON and read them back.

`FocusWorkspaceNumber` shows another workspace of the focused monitor
([`WindowManager::focus_workspace`]). `MoveContainerToWorkspaceNumber` takes the focused
container (or the focused window, when it is a floating one) to the back of another workspace
of the monitor and shows that workspace, and `SendContainerToWorkspaceNumber` does the same
and leaves the workspace in front showing ([`WindowManager::move_container_to_workspace`]). A
workspace that does not exist yet is created, with the ones before it, and gets a desktop.

The other workspace commands are made of the same two operations. `CycleFocusWorkspace`,
`CycleMoveContainerToWorkspace` and `CycleSendContainerToWorkspace` take the next or the previous
workspace, which wraps around, and `CycleFocusEmptyWorkspace` the next or the previous with no
window. A monitor remembers the workspace that was in front before ([`Monitor::focus_workspace`]
records it), which `FocusLastWorkspace`, `MoveContainerToLastWorkspace` and
`SendContainerToLastWorkspace` take. `FocusWorkspaceNumbers` shows a workspace on every monitor.
`WorkspaceName` names a workspace, `EnsureNamedWorkspaces` gives a monitor named workspaces, and
`FocusNamedWorkspace`, `NamedWorkspaceLayout` and `NamedWorkspaceTiling` look a workspace up by
its name on every monitor ([`WindowManager::monitor_workspace_index_by_name`]); a name no
workspace has changes nothing. `FocusNamedWorkspace` focuses the monitor that has the workspace
([`WindowManager::focus_monitor`]). `WorkspaceLayout` and `WorkspaceTiling` set the layout and the
tiling of a workspace by index. `NewWorkspace` adds a workspace and shows it, `EnsureWorkspaces`
gives a monitor workspaces up to a number, and `CloseWorkspace` removes the workspace in front
when it has no window and no name and is not the monitor's last. A name is komorebi's: the
compositor's desktops keep theirs.

A window the compositor reports shown or focused on a monitor that is not the focused one
focuses that monitor ([`WindowManager::monitor_idx_from_window`]). The monitor commands work on
the ring of monitors: `FocusMonitorNumber`, `CycleFocusMonitor` and `FocusMonitorAtCursor` focus
one ([`WindowManager::focus_monitor`]), and `FocusMonitorWorkspaceNumber` a workspace of it;
`MoveContainerToMonitorNumber`, `SendContainerToMonitorNumber`, their cycle and monitor-workspace
forms, and `MoveContainerToNamedWorkspace` and `SendContainerToNamedWorkspace` take the focused
container to another monitor, put its windows on the desktop of the workspace they go to, and tile
both monitors ([`WindowManager::move_container_to_monitor`]); `MoveWorkspaceToMonitorNumber` and
`CycleMoveWorkspaceToMonitor` take the workspace in front to another monitor, and
`SwapWorkspacesToMonitorNumber` exchanges the workspaces of two monitors.
`DisplayIndexPreference` gives a monitor, by its serial number id, the index the window manager
puts it at when it loads the monitors, with placeholders before it while the monitors in between
are not connected. `EagerFocus` focuses the first window of an executable, searching every
workspace of every monitor, and shows its workspace.

`PreselectDirection` reserves the index on one side of the focused container for the next
window ([`WindowManager::preselect_container_in_direction`]). The workspace inserts an empty
container there ([`Container::preselect`]), which [`Workspace::update`] keeps and the layout
gives a tile, and [`Workspace::new_container_for_window`] puts the next window in it.
`CancelPreselect` removes it. A workspace reserves one place at a time, and the grid layout
none.

## Dragging

The user can move a window with the pointer, and resize it by dragging an edge. KWin reports the
start and the end of a drag (`interactiveMoveResizeStarted` and `interactiveMoveResizeFinished`),
the bridge sends both with the window's frame, and the end with where the pointer is, and the
table turns a move into a `MoveStart` and a `MoveEnd`, and a resize into a `ResizeStart` and a
`ResizeEnd` ([`Table::handle`]). The bridge also stops asking KWin again for the position komorebi
gave the window (`settle`): the window is the user's now.

`MoveStart` records the monitor, the workspace and the window
([`WindowManager::pending_move_op`]). `MoveEnd` takes the record, and when it names the same
window, looks at the monitor under the pointer. On another monitor than the one the move began
on, the window's container goes there and takes the place of the container whose tile the
pointer is on ([`WindowManager::transfer_window`]); a floating window joins the floating
windows there, a monocle container is put back among the containers first, and a maximized
window stays where it is. Both monitors are tiled again.

On the same monitor, `MoveEnd` compares the frame of the focused container's window with the
tile the layout last gave it ([`Workspace::latest_layout`]). A frame as wide and as tall as its
tile makes the drag a move. With the float override on, the window is then made a floating one
where it was let go. Otherwise the container under the pointer
([`Workspace::container_idx_from_current_point`], through the backend's `cursor_pos`) is the
target: the focused container swaps with it, or, with the window container behavior `Append`,
the window joins it ([`Workspace::move_window_to_container`]). The workspace is tiled again,
which puts a window let go where there is no tile back on its own. A frame of another size
changes nothing, and neither does a floating window, which is in no container
([`Workspace::contains_managed_window`]). The swap goes through `LockableSequence`, as
`MoveWindow`'s does.

A resize is measured from the frame the window had when the user took hold of it. The table keeps
that frame at the start ([`Table::drag_origin`], the backend's `drag_origin`), because the
`geometry` events of the drag change the window's frame before the window manager gets to the start;
a backend that keeps none, as the fake, gives the frame the window has when `ResizeStart` is
handled. `ResizeStart` records the window and that frame ([`WindowManager::pending_resize_op`]). At
the end the edges are where the user took them, which is not where the window's frame is: KWin
changes the frame once the client has drawn at the new size, and goes on reporting the client's
frames after the end of the drag, which can be before the window manager, busy with an earlier
event, gets to the end. The bridge therefore keeps the frame the last step of the drag asked for
(`interactiveMoveResizeStepped`) and sends it with the end as `requested`, and the table keeps it
apart from the window's frame ([`Table::drag_end`], the backend's `drag_end`), where a frame event
cannot reach it. `ResizeEnd` compares each edge of that frame, or of the window's frame when there
is none (a drag with no step), with the same edge of the frame the drag began with, focuses the
container of the dragged window, and calls [`WindowManager::resize_window`] for each edge that
moved, with twice the distance, since the layout moves a shared edge by half of what it is given. If
the window is in a container of a workspace that tiles, and the frame changed, the workspace is
tiled again, which also puts back a window whose edge had no neighbor to take room from.
[drag-resize.md](../drag-resize.md) has the rules and the reasons for each.

The neighbors follow the edge while it is dragged, and the animation effect, which does not
animate a resize by the user, leaves them to move at once. At every step of a resize KWin reports the
frame the pointer asks for (`interactiveMoveResizeStepped`); the bridge sends one step every 16 ms
at most, the newest, from a single-shot timer that sends the last one of a burst, and the table
makes the frame the window's and raises a `ResizeStep`. [`send_notification`] keeps at most one
`ResizeStep` waiting in the channel, and drops the others: the window manager reads where the
edge is when it gets to the step. `ResizeStart` keeps the workspace's
[`Workspace::resize_dimensions`] and [`Workspace::latest_layout`] as they are when the user takes
hold ([`LiveResize`], in [`WindowManager::live_resize`]), and puts the window in the list of
windows being resized ([`live_resize_begins`]), which [`Window::set_position`] leaves alone. A
step puts the kept layout back, applies the drag so far as `ResizeEnd` does, and tiles the
workspace; it makes no notification. `ResizeEnd` takes the window out of the list, puts the kept
layout back if a step moved the neighbors, and does the whole drag on it, so a drag ends the same
with steps as without, and one that is taken back puts the neighbors back. A window that opens or
closes part way through a drag changes the number of tiles: the kept layout is dropped, and the
steps after it change nothing until the end.

## Configuration

The daemon is configured by `komorebi.json`, which [`StaticConfig`] reads. `main.rs` takes the
file `--config` names, or else `komorebi.json` in [`HOME_DIR`] (`$KOMOREBI_CONFIG_HOME`, or
`~/.config/komorebi`) if there is one; without a file, the daemon runs on its defaults. Loading
has three steps, because the monitors are known only after the backend is asked:

1. [`StaticConfig::preload`] reads the file, applies the settings that are process-wide (the
   default paddings, [`LAYOUT_DEFAULTS`], the indices of the monitors, the settings of the borders
   in [`border_manager`], and the rules in [`IGNORE_IDENTIFIERS`], [`MANAGE_IDENTIFIERS`] and
   [`FLOATING_APPLICATIONS`]) and makes the [`WindowManager`], with the settings that are its own.
   It starts a watcher on the file.
2. [`WindowManager::init`] loads the monitors and the windows from the backend, in the order the
   indices of the monitors give.
3. [`StaticConfig::postload`] gives each monitor the entry of the file that is its own, and each
   workspace of the monitor the entry of its place ([`Workspace::load_static_config`]). A monitor
   takes the entry at the index `display_index_preferences` gives its serial number id, or else
   the first entry that no preference names and no monitor has taken. `main.rs` then asks the
   backend for a desktop for each workspace ([`WindowManager::sync_workspace_desktops`]), and
   tiles.

When the file changes, the watcher (a [`hotwatch`] watcher, which waits two seconds for a file
to settle) writes `ReloadStaticConfiguration` to the daemon's own socket, and the message is
handled like any other, with the window manager locked: [`StaticConfig::reload`] reads the file
first and applies it only when it parsed, so a file that is half written changes nothing. It does
for the window manager that is running what the three steps do for one that starts, and tiles
every monitor again.

`app_specific_configuration_path` names files of rules for particular applications, which
[`StaticConfig`] reads after the rules of its own (`apply_globals`): the `ignore`, `manage` and
`floating` rules of each application in each file are appended to the same lists, once each (a
rule that is in the list already is not added again). A path with no file is skipped with a
warning, since one `komorebi.json` may name a file that only another platform has; a file that is
there and is not an applications.json is an error.

Three kinds of key reach the model. A **setting** of the window manager is a field of it
([`WindowManager::resize_delta`] and the others). A **default** is a process-wide static that a
monitor or a workspace falls back to when it has no value of its own: the paddings, the layout
defaults. The settings of the borders are statics too, which the file sets and
[`border_manager::current_look`] and the layout read. A **rule** is an entry of one of the
process-wide lists. A workspace's own `layout_rules`, `work_area_offset_rules` and
`window_container_behaviour_rules` are fields of the [`Workspace`], which [`Workspace::update`]
reads each time it tiles.

A workspace's `workspace_rules` and `initial_workspace_rules` are not fields of the window manager
but entries of [`WORKSPACE_MATCHING_RULES`], which [`StaticConfig::postload`] and
[`StaticConfig::reload`] empty and fill from the file, and the messages `WorkspaceRule`,
`InitialWorkspaceRule` and their named forms add to. [`WindowManager::enforce_workspace_rules`] reads
them: for each window in view (the top of each container, and the floating windows) that a rule
matches, on a workspace other than the rule's, it makes an operation, takes the window out of its
workspace (and hides it when that is the focused one), puts it in the target (making the workspace
if it is not there, and taking a floating window to the target's monitor), tiles the focused
workspace again if the window left it, and has each target monitor put its windows on the desktops
of their workspaces
([`Monitor::assign_windows_to_workspaces`]). `handle_event` calls it before every event about a
window it manages, and `postload`, `reload` and `EnforceWorkspaceRules` call it too. An `initial_only`
rule moves a window once: the window id goes into [`WindowManager::already_moved_window_handles`],
which `EnforceWorkspaceRules` empties and a destroy removes the id from.

`ReplaceConfiguration` is the third way in: [`WindowManager::process_command`] checks that the file
reads as a [`StaticConfig`], pauses the old window manager and brings back the windows it hid
([`WindowManager::restore_all_windows`]), makes a new window manager from the file
([`StaticConfig::preload`], [`WindowManager::init`], [`StaticConfig::reload`]) over the same command
socket, and puts it where the old one was, so the daemon starts over from the file, with the
windows the backend has, all of them in view, and a watcher on the new file. A file that does not read is logged and the old window manager stays.
`komorebic quickstart` writes the example file of the docs and `komorebic/applications.json` into
the config home, compiled into the binary, and asks before it writes over a file;
`komorebic enable-autostart` writes the XDG autostart entry that has Plasma start the daemon at login.

The same types describe the file as a JSON Schema, which `schemars` derives: `komorebic
static-config-schema` prints the schema of [`StaticConfig`], `application-specific-configuration-schema`
that of an applications file, and `notification-schema` and `socket-schema` those of a
[`Notification`] and of a [`SocketMessage`]; the daemon answers the same four questions on its
socket (the fourth is the schema of a list of applications files, where `komorebic` prints the
schema of one).
The schemas of the first two are committed (`schema.json`, `schema.asc.json`, written by `just
jsonschema`), and so are the options the module's `config` is typed with
(`nix/komorebi-options.nix`, which `schemars-nixgen` makes from `schema.json` and `just nixgen`
gives the hash of the schema as its first line). The check `schema-fresh` compares the schemas with
what the Rust types print and the hash with the schema, so a change to a key that leaves one of
them behind fails.

One `komorebi.json` is meant for every platform komorebi runs on, so [`StaticConfig`] has no
`deny_unknown_fields`: a key it does not read is dropped, and the keys of other platforms that
mean nothing on KDE Plasma are fields that nothing reads. `StaticConfig::from(&WindowManager)`
goes the other way, for `GenerateStaticConfig`.

| Rule | Enforced by | Proof | Escape hatch |
|---|---|---|---|
| A key komorebi does not read does not stop a configuration from loading | serde: [`StaticConfig`] ignores unknown keys, and a key of another platform is a field nothing reads | `the_keys_that_do_nothing_on_kde_are_accepted_and_ignored`, `fixtures_load_round_trip_and_only_lose_windows_only_keys` | none |
| The keys the parity test ignores are keys `StaticConfig` does not read | test: the ignore lists are compared with the schema of [`StaticConfig`] | `the_lists_name_no_key_that_is_read` | none |
| The example in the docs is the example file, which loads | test | `the_example_in_the_docs_is_the_example_file`, `fixtures_load_round_trip_and_only_lose_windows_only_keys` | none |
| A path to an applications file that is not there is skipped, and one that is there and is broken is an error | framework path: `handle_asc_file` returns early when the path does not exist, and parses the file otherwise | `a_missing_application_specific_configuration_is_skipped_not_fatal`, `an_application_specific_configuration_that_exists_but_is_broken_is_still_an_error`, `a_file_that_is_not_there_is_skipped_and_one_that_is_broken_is_an_error` | none |
| The rules of an applications file and of the configuration add up | framework path: both are appended to the process-wide lists | `the_rules_of_the_configuration_and_of_the_file_add_up`, `every_file_of_a_list_is_read` | none |
| `schema.json` and `schema.asc.json` are what the Rust types print | Nix check `schema-fresh`, and a test that compares them with `komorebic`'s output | `schema-fresh`, `the_schema_files_of_the_repository_are_what_the_subcommands_print` | `just jsonschema` |
| The options the module is typed with are made from the committed schema | the hash of `schema.json` in the first line of `nix/komorebi-options.nix`, compared by `schema-fresh` | `schema-fresh` | `just nixgen` |
| The example, in Nix and in JSON, follows the schema, and says the same in both | Nix check `nix-options-validation`: the options evaluated against the Nix example, both examples checked with `check-jsonschema`, and one contained in the other | `nix-options-validation` | none |
| A window a workspace rule names ends on its workspace, and on that workspace's desktop once the workspace is shown | framework path: [`WindowManager::enforce_workspace_rules`] moves it in the model, and has the target monitor put it on the desktop | `a_rule_sends_the_window_of_an_application_to_its_workspace`, `a_window_a_rule_moves_between_workspaces_that_are_out_of_view_is_put_on_the_new_desktop`, `vm-workspace-rules` | none |
| A window a workspace rule takes off the workspace in front is out of sight until its workspace is shown | framework path: [`WindowManager::enforce_workspace_rules`] hides it, and showing the workspace restores it | `a_rule_sends_the_window_of_an_application_to_its_workspace`, `vm-workspace-rules` | none |
| An initial rule sends a window once, a permanent one every time | framework path: the window ids an initial rule has sent are in [`WindowManager::already_moved_window_handles`] until the window closes | `an_initial_rule_moves_a_window_once_and_a_permanent_one_every_time`, `vm-workspace-rules` | `komorebic enforce-workspace-rules` forgets them |
| The rules of the configuration are the file's, and the windows that are open follow them | framework path: [`StaticConfig::postload`] and [`StaticConfig::reload`] empty the list, fill it from the file and enforce it | `the_rules_of_komorebi_json_send_the_windows_that_are_open_and_come_out_in_the_generated_file`, `vm-workspace-rules` | none |
| Replacing the configuration with a file that does not read leaves the window manager as it was | framework path: the arm reads the file as a [`StaticConfig`] before it makes anything | `replacing_the_configuration_makes_the_window_manager_again_from_the_new_file` | none |
| Replacing the configuration leaves no window hidden | framework path: the arm brings back the windows the old window manager hid ([`WindowManager::restore_all_windows`]) before the new one reads the desktop | `replacing_the_configuration_makes_the_window_manager_again_from_the_new_file` | none |
| `quickstart` never writes over a file without being told to | framework path: every file goes through `write_file_with_prompt`, which keeps the file unless the answer is `y` or `yes` | `quickstart_writes_the_example_files_and_asks_before_it_overwrites_one` | none |
| The entry `enable-autostart` writes is one the session runs | VM test: systemd's autostart generator makes a unit of it, which starts a daemon | `autostart_writes_an_xdg_entry_that_starts_komorebi_and_takes_it_away_again`, `vm-module` | none |
| A file that cannot be read changes nothing | framework path: [`StaticConfig::reload`] reads and parses the file before it applies anything | `a_configuration_that_cannot_be_read_changes_nothing`, `the_daemon_follows_the_file_it_is_given_when_the_file_changes` | none |
| The daemon applies a change to its file, written in place or replaced by a rename | framework path: the watcher sends `ReloadStaticConfiguration` to the daemon's own socket | `the_daemon_follows_the_file_it_is_given_when_the_file_changes`, `vm-module` | none: the file has to be the one the daemon was started with |
| A monitor takes the entry its display index preference gives it, else the first nobody has | framework path: [`StaticConfig::postload`] and [`StaticConfig::reload`] choose the entry by serial number id first | `a_monitor_takes_the_configuration_its_display_index_preference_gives_it` | none |
| A workspace that names no layout and does not say it tiles moves no window | framework path: [`Workspace::load_static_config`] sets [`Workspace::tile`] | `a_workspace_with_no_layout_does_not_tile`, `a_workspace_tiles_when_it_has_a_layout_or_is_told_to` | `"tile": true` |
| A workspace's own layout options replace the defaults of its layout, whole | framework path: [`Workspace::update`] takes the workspace's options and rules when it has either, and else those of `layout_defaults` | `layout_options_of_a_workspace_replace_the_defaults_of_its_layout` | none |
| The highest of the rules a count of containers reaches decides the layout, the offset and the container behavior | framework path: [`Workspace::update`] reads the rules, kept in the order of their thresholds | `layout_rules_change_the_layout_with_the_number_of_windows`, `work_area_offset_rules_change_the_offset_with_the_number_of_windows`, `window_container_behaviour_rules_change_the_behaviour_with_the_number_of_containers` | none |
| A workspace's own container behavior and float override come before the one for every workspace, and its floating layer behavior before its monitor's, which comes before the one for every workspace | framework path: [`WindowManager::window_management_behaviour`] reads the workspace, then (for the floating layer) the monitor, then the window manager | `the_behaviour_of_a_workspace_comes_before_the_one_for_every_workspace`, `the_float_override_of_a_workspace_comes_before_the_one_for_every_workspace`, `the_floating_layer_behaviour_of_a_workspace_comes_before_a_monitors_and_that_before_the_default` | none |
| The configuration the daemon generates loads and says the same | test | `a_configuration_comes_out_again_as_the_settings_of_the_window_manager` | none |
| The daemon reads the file it is given or the one in the config home, not both | startup order: `main.rs` takes `--config` before the config home | `the_daemon_follows_the_file_it_is_given_when_the_file_changes`, `the_daemon_reads_komorebi_json_from_the_config_home` | none |

## The look

komorebi decides what the windows look like and the compositor draws it, since only the
compositor has the frames, the corners and the shadows. A border is the outer outline of a window,
drawn outside it, in the gap the layout leaves between tiles, and an animation is a window
sliding to its new place instead of jumping there. The window manager describes a
[`Look`] and asks the backend for it ([`Backend::apply_look`]); the backend sees that it is drawn
and answers whether borders are being drawn. The reasons are in
[DESIGN.md](DESIGN.md#why-does-the-compositor-draw-the-borders-and-not-komorebi).

[`border_manager`] holds the settings of the border, as statics that the messages `Border`,
`BorderWidth` and `BorderOffset` set: whether borders are on, their width, the offset, the radius
of the corners and the two colors. [`animation`] holds the settings of the animation, which
`Animation`, `AnimationDuration`, `AnimationStyle` and `AnimationFps` set: whether windows are
animated, for how long and with what easing, for every kind of animation or for one
([`AnimationPrefix`]; movement is the only kind). The
settings of one kind win over the global ones, and a global setting clears the ones of the kinds.
The commands that change a stack turn the animation off while they run and put it back, as
komorebi does on the other platforms; the file's `animation` key sets the same settings.
[`border_manager::current_look`] makes the [`Look`] of them all, and
[`border_manager::send_notification`] asks the backend for it and keeps the answer in
[`BORDER_DRAWN`]. It is called before the first layout, after every event and every message, and
after every retile. A backend remembers the look it applied last and does nothing when it is asked
for the same again, so nothing reaches KWin unless a setting changed.

What a window is to the layout decides the color of its border: the focused window of the focused
container on the focused monitor is `Single`, or `Stack` when its container has more than one
window, the focused window of every other container is `Unfocused` or, when the container is
locked, `UnfocusedLocked`, and a floating window is `Floating` while it has the focus and
`Unfocused` otherwise ([`border_manager::window_kinds`]). After every event and every message
[`border_manager::update_colours`] tells the backend the color of each window's border
([`Backend::set_border_colours`]), or that none has one when borders are off, and the backend sends
nothing it sent last time. `BorderColour` sets the color of one kind.

A drawn border takes room. While [`BORDER_DRAWN`] is set, [`Monitor::update_workspace_globals`]
gives the workspace the width and the offset of the border, and [`Workspace::update`] takes both
off every side of every tile, so the border falls in the gap and not on the window next to it.
Without a border, because they are off or the compositor has no effect to draw one, the room is
given back the next time the workspace is tiled.

The KWin backend draws the border with the effect KDE Rounded Corners
([`kwin::effects`](../../komorebi/src/kwin/effects.rs)). `apply_look` writes the effect's settings
into the user's `kwinrc`, group `[Round-Corners]`, through [`Kwinrc`]; loads the effect with
`loadEffect` unless it is loaded; and always asks it to read its settings again
(`reconfigureEffect`), since KWin hands an effect the copy of `kwinrc` it read when it started. A
look without a border unloads the effect, if komorebi loaded it, and puts the user's settings
back. `shutdown` does the same. An effect KWin did not find when it started is reported once and
komorebi goes on without it, with `apply_look` answering false. The animation is Geometry Change:
its `Duration` and `Curve` are the look's, and cross-fading is off. The curve is a Qt easing
curve, the name of the style without its "Ease" ([`AnimationStyle::qt_curve`]); the stock effect
ignores `Curve` and eases out exponentially, and komorebi's build of it reads it. KWin animates
what is painted, so the
frame the table reads is the final one at once and nothing waits for an animation to end. The
stock border effect has one color for
the active window and one for the others; komorebi's build of it takes a color for each window,
over D-Bus, by the UUID KWin knows the window by. `set_border_colours` answers false, and logs it
once, when the effect is the stock one: every border is then the focused or the unfocused color of
the look.
[PLATFORM.md](PLATFORM.md#kwin-effects) has the effect, its settings and what was measured.

## Themes

A theme gives the borders their colors. The `Theme` message carries a [`KomorebiTheme`]: a
Catppuccin theme, a Base16 theme or a Base16 palette, each with the color it gives to each of the
six kinds of border, and a default for the ones it does not name.
[`theme_manager::send_notification`] puts the six colors into the statics of [`border_manager`],
keeps the theme as [`theme_manager::CURRENT_THEME`] and asks the backend for the look again, on
the thread that handled the message; [`border_manager::update_colours`] hands them to the border
effect with the next event or message. The palette of a picture is made by
`komorebi-themes` ([`komorebi_themes::generate_base16_palette`]), which takes seconds, so
[`theme_manager::wallpaper_palette`] keeps each palette it makes in `komorebi` in the user's cache
directory, in a file named by [`theme_manager::palette_file`] for the picture, a hash of its path,
size and time of last change, and the variant: a picture that was painted over, or one of the same
name in another folder, has a palette of its own. A picture it cannot make a palette from (it
cannot be read, or has fewer than eight colors) has none, and the borders keep their colors.
[DESIGN.md](DESIGN.md#why-is-a-palette-kept-by-the-hash-of-its-picture) has the reason.

## Wallpapers

A [`Monitor`] has a [`Wallpaper`] and so can each of its workspaces: the `wallpaper` of an entry of
`monitors` and of `workspaces` in `komorebi.json`, which [`StaticConfig::postload`] and
[`StaticConfig::reload`] give them. [`Workspace::apply_wallpaper`] asks the backend to show the workspace's own wallpaper
or else its monitor's ([`Backend::set_wallpaper`]), and, unless the wallpaper says
`generate_theme: false`, makes a theme of the palette of the picture
([`theme_manager::wallpaper_palette`]), with the variant and the colors of its `theme_options`, and
hands it to [`theme_manager::send_notification`]: the colors are the borders' before the
workspace is shown. It is called wherever a workspace comes into view. [`Workspace::restore`], which
[`Monitor::load_focused_workspace`] calls for komorebi's own switches, calls it;
[`WindowManager::adopt_workspace_change`] calls it for a switch something else made, and
[`WindowManager::retile_all`] for the workspace in front at the start, and
[`WindowManager::apply_wallpaper_for_monitor_workspace`], which [`StaticConfig::reload`] calls for the
workspace each monitor shows, has a reloaded file's wallpapers shown at once. A monitor and a
workspace without a wallpaper are not asked about.

Plasma has one wallpaper for each screen, which the shell, a process of its own, keeps. The KWin
backend does not set it from the thread of the window manager: [`Backend::set_wallpaper`] notes the
wish for the output (by name, which is how the shell tells screens apart) and starts a task on the
runtime, which asks the shell what the screen shows and sets the picture only if it differs, with
the plugin that shows a picture, filling the screen ([`kwin::wallpaper`]). A shell that is not
there yet is tried again for about half a minute, with longer waits, and the failure is said once.
[PLATFORM.md](PLATFORM.md#the-plasma-shell) has what the shell is asked.

## Transparency

The opacity of a window is a property KWin has, so komorebi sets it ([`Backend::set_opacity`],
which the KWin backend sends the bridge as an `opacity` command: `alpha / 255`) and the compositor
draws the window so. [`transparency_manager`] holds the settings, as statics that `Transparency`,
`ToggleTransparency` and `TransparencyAlpha` set and the `transparency` and `transparency_alpha`
keys of the file give a value, and the rules for the ignored windows (`TRANSPARENCY_BLACKLIST`, set
by the `transparency_ignore_rules` of the file). [`transparency_manager::apply`] is called
before the first layout and after every event and every message: it works out
[`transparency_manager::transparent_windows`], on the workspace each monitor shows (the window in
front in every container, unless the container has the focus on the focused monitor; a monocled
window only on a monitor that is not the focused one; none on a workspace that does not tile; none
that a rule ignores), and sends the backend only what differs
from what the window manager kept in [`WindowManager::opacity_applied`]. A window that should not
be see-through any more is made opaque, and with transparency off every window is. When komorebi
stops, [`transparency_manager::restore`] makes every window it changed opaque again. The border
effect draws a window from a texture that has its opacity in it, and the build komorebi installs
draws it again when the opacity changes ([PLATFORM.md](PLATFORM.md#the-patches)).

## Focus follows mouse

The window under the pointer has the focus when the compositor's focus policy says so, and the
compositor does it. `FocusFollowsMouse` and `ToggleFocusFollowsMouse` set
[`WindowManager::focus_follows_mouse`] (the implementation that was asked for, or none) and ask the
backend ([`Backend::set_focus_follows_mouse`]); whichever of the two implementations is named, on
KDE it is the compositor's own policy. The KWin backend writes `FocusPolicy=1` and
`DelayFocusInterval=0` into the `[Windows]` group of the user's `kwinrc` through [`Kwinrc`], which
records the first value of each key, and asks KWin to reload; turning it off puts those two keys
back ([`Kwinrc::restore_keys`]) and leaves `PerOutputVirtualDesktops`, which is in the same group,
as it is. `shutdown` puts back everything. The focus the compositor gives is an event like the
others: the window manager follows it, and [`State`] says whether focus follows mouse is on.
[DESIGN.md](DESIGN.md#why-is-focus-follows-mouse-kwins-own-focus-policy) has the reasons.

## The NixOS module

The flake exports one module under two names, `nixosModules.default` and
`nixosModules.komorebi`: [`nixos-module.nix`] and the flake's overlay, which builds
`komorebi-full` (both programs) with the flake's nixpkgs and Rust toolchain. Its options are
`enable`, `package` (by default `pkgs.komorebi-full`, from the overlay), `logLevel`,
`configFile`, `config`, `applicationSpecificConfiguration`, `effects.borders.enable` and
`effects.borders.package` (by default `pkgs.kde-rounded-corners-komorebi`, from the overlay),
`effects.animation.enable` and `effects.animation.package`
(`pkgs.kwin-effect-geometry-change-komorebi`), and `execStart`, which is read-only: the module
sets it to `bin/komorebi` of the package with `--log-level`, and `--config` with a
`komorebi.json` when `configFile` or `config` is set. `config` is typed from
`nix/komorebi-options.nix`, the options `schemars-nixgen` makes from the schema of `komorebi.json`;
the module writes it as JSON, with no null in it, and `configFile` and the written file both go
through `check-jsonschema` against `schema.json` when the system is built (comment lines taken out
first, since the checker reads plain JSON). `applicationSpecificConfiguration.sources` are files
fetched from GitHub that become `app_specific_configuration_path`; the module has none by default.
`internal.configAttrs` is the configuration as the attribute set the options make, for the tests.
With `services.komorebi.enable`, the module:

- installs the package in the system profile, and the effect that draws the borders unless
  `effects.borders.enable` is off and the one that animates windows unless
  `effects.animation.enable` is off;
- defines the user unit `komorebi.service`, which every user of the machine has. Plasma's
  `plasma-workspace.target` wants it, so a Plasma session starts it at login, and it is ordered
  after `plasma-core.target`, which Plasma orders after KWin's service, `plasma-kwin_wayland`;
- runs `execStart` in it, with `Restart=on-failure`, the exit status of a `SIGTERM` (130)
  counted as success, and a `PATH` of `/run/wrappers/bin`, `/etc/profiles/per-user/%u/bin` and
  `/run/current-system/sw/bin` instead of the store paths NixOS gives a unit;
- asserts that Plasma 6 is enabled.

The VM tests run on machines built with it ([vm-tests.md](vm-tests.md)). Their headless node
runs the daemon in test sessions, with a template unit, `komorebi@NAME`, that runs the module's
`execStart` on the session's private bus. The session node logs in to Plasma, which starts the
module's unit.

| Rule | Enforced by | Proof | Escape hatch |
|---|---|---|---|
| komorebi is enabled only on a machine with Plasma 6 | evaluation error: an assertion of the module | `nixos-module-eval` ("without Plasma 6, an assertion fails") | none |
| The log level is one the daemon accepts | evaluation error: `logLevel` is an enum of the daemon's `--log-level` values | `nixos-module-eval` ("a log level the daemon does not have does not evaluate") | none |
| The unit runs `execStart`, and nothing but the module sets it | evaluation error: the option is read-only | `nixos-module-eval` ("execStart cannot be set", "the unit runs execStart") | a unit of your own |
| The daemon is configured by `configFile` when it is set, else by `config` | framework path: `execStart` passes the checked file as `--config`, which comes before the config home | `nixos-module-eval` ("configFile reaches execStart and the unit as --config", "config reaches execStart ..."), `vm-module` | none: with neither the daemon reads the file of the config home |
| A configuration with a layout or a value komorebi does not have does not build | evaluation error: `config` is typed from the schema; and `check-jsonschema` fails the build for a file that does not follow it | `nixos-module-eval` ("a layout komorebi does not have does not evaluate"), `nix-options-validation` | `configFile` with a file the schema accepts |
| The sources of application specific configuration reach the daemon only while `applicationSpecificConfiguration.enable` is set | framework path: the module adds `app_specific_configuration_path` to the file it writes only when `enable` is set and there are sources | `nixos-module-eval` ("with applicationSpecificConfiguration.enable = false, the sources are left out of config", "with the sources turned off and no config, there is nothing to write") | none |
| `komorebi` and `komorebic` are on every user's `PATH` | the module installs the package in the system profile | `nixos-module-eval`; every VM suite runs `komorebic` | none |
| The border effect is installed with komorebi, and only by the module | the module installs `effects.borders.package` in the system profile when `effects.borders.enable` is set | `nixos-module-eval` ("the border effect is installed in the system profile", "with the border effect off, komorebi is installed and the effect is not"), `vm-look` | `effects.borders.enable = false` |
| The border effect the module installs is built for the KWin of the system and is not loaded until komorebi asks | the package: `kde-rounded-corners-komorebi` links the `libkwin` of the nixpkgs' KWin and says `EnabledByDefault` false in its metadata | the `kde-rounded-corners-komorebi-install` check | `effects.borders.package` |
| The animation effect is installed with komorebi, and not loaded until komorebi asks | the module installs `effects.animation.package` when `effects.animation.enable` is set, and the package's metadata says `EnabledByDefault` false | `nixos-module-eval` ("the animation effect is installed in the system profile", "with the animation effect off, ..."), the `kwin-effect-geometry-change-komorebi-install` check, `vm-look` | `effects.animation.enable = false` |
| Every Plasma session starts komorebi, once KWin's service has started | systemd: the user unit is wanted by `plasma-workspace.target`, after `plasma-core.target` | `nixos-module-eval`, `vm-module` | `systemctl --user mask komorebi` |
| A daemon that fails or is killed is started again | systemd: `Restart=on-failure` | `vm-module` (`SIGKILL`) | none |
| A daemon that is told to stop stays stopped, and the unit is not failed | systemd: the exit statuses of `Stop` (0) and of `SIGTERM` (130) are successes | `vm-module` | none |
| The daemon has the `PATH` of a terminal in the session | the unit's environment, with NixOS's default `PATH` turned off | `nixos-module-eval`, `vm-module` | none |
| The VM suites run komorebi as the module installs it | framework path: the test nodes import the module, and `komorebi@NAME` runs its `execStart` | every VM suite | a suite's `node` can set `services.komorebi.enable = false` (`vm-render-smoke` does) |

## The parts

- [`backend`](../../komorebi/src/backend/mod.rs): the trait, the two data types, and the
  process-wide handle ([`set_backend`], [`backend`], [`with_backend`]).
- [`backend::fake`](../../komorebi/src/backend/fake.rs): the fake.
- [`ring`](../../komorebi/src/ring.rs): the [`Ring`], and the macro that gives every type
  holding one the same accessors (`containers()`, `focused_container_mut()`, ...).
- [`monitor`](../../komorebi/src/monitor.rs), [`workspace`](../../komorebi/src/workspace.rs),
  [`container`](../../komorebi/src/container.rs), [`window`](../../komorebi/src/window.rs):
  the four levels of the tree; `window` also has the rule engine ([`should_act`]).
- [`lockable_sequence`](../../komorebi/src/lockable_sequence.rs): inserting, removing and
  swapping in a list where some elements are locked in place, which is how a workspace
  changes its containers.
- [`window_manager`](../../komorebi/src/window_manager.rs): the [`WindowManager`] and the
  operations on it (tile the workspace in front, tile every monitor, take a minimized
  window out, move the focus, move the focused container, change the layout, resize or
  promote the focused container, float a window, switch the layer, put a container in
  monocle, maximize a window, lock a container, set the padding of a workspace, manage and
  unmanage a window, stack and unstack windows and choose the one in front, show a
  workspace, move a container to another workspace, follow a workspace switch made by
  something else, name a workspace and find it by its name, set the layout of a workspace
  that is not in front, focus another monitor, and move containers and workspaces between
  monitors).
- [`desktop`](../../komorebi/src/desktop.rs): loads the monitors and the open windows from
  the backend, and reads the sizes of the monitors again.
- [`window_manager_event`](../../komorebi/src/window_manager_event.rs) and
  [`process_event`](../../komorebi/src/process_event.rs): the events, and what the window
  manager does with each.
- [`window_manager_event_listener`](../../komorebi/src/window_manager_event_listener.rs): the
  channel that carries events from the backend to the window manager, and
  [`listen_for_events`], the thread that takes them off it.
- [`monitor_reconciliator`](../../komorebi/src/monitor_reconciliator.rs): the channel the KWin
  backend sends [`MonitorNotification`]s on, [`listen_for_notifications`], the thread that
  takes them, and [`reconcile_display_change`], which brings the window manager's monitors in
  line with the outputs;
  [`reconcile`](../../komorebi/src/reconcile.rs): moves what was on a monitor that went to the
  monitors that are left.
- [`kwin`](../../komorebi/src/kwin/mod.rs): the KWin backend, its D-Bus service and the held
  call; [`kwin::state`](../../komorebi/src/kwin/state.rs), the table;
  [`kwin::kwinrc`](../../komorebi/src/kwin/kwinrc.rs), the editor of the user's `kwinrc`, which
  keeps the values it changes and puts them back; the parking desktop is made, swept and removed
  in `kwin` and tracked in `kwin::state`; and
  [`bridge.js`](../../komorebi/src/kwin/bridge.js), the bridge.
- [`static_config`](../../komorebi/src/static_config.rs): `komorebi.json`, [`StaticConfig`], and
  how it is loaded, reloaded and generated.
- [`border_manager`](../../komorebi/src/border_manager/mod.rs): the border settings, and the
  [`Look`] they make, which it asks the backend for.
- [`animation`](../../komorebi/src/animation/mod.rs): the animation settings, which the look has.
- [`theme_manager`](../../komorebi/src/theme_manager.rs): a theme's colors for the borders, and the
  palettes made from pictures.
- [`kwin::wallpaper`](../../komorebi/src/kwin/wallpaper.rs): the Plasma shell's side of a
  wallpaper: the screen of an output, what it shows, and the picture set.
- [`transparency_manager`](../../komorebi/src/transparency_manager.rs): which windows are
  see-through, and the opacity they are given.
- [`kwin::effects`](../../komorebi/src/kwin/effects.rs): the KWin effect that draws the border,
  its settings and the state komorebi keeps of it.
- [`process_command`](../../komorebi/src/process_command.rs): the thread that listens on the
  socket, and what the window manager does with each message.
- [`state`](../../komorebi/src/state.rs): the [`State`] a `State` message is answered with,
  and whether an event or a message changed it.
- [`lib.rs`](../../komorebi/src/lib.rs): the subscribers, the [`Notification`], and
  [`notify_subscribers`].
- [`komorebi-client`](../../komorebi-client/src/lib.rs): a library that writes messages on
  the socket and reads the answers, and subscribes to notifications, for programs that talk
  to the daemon.
- [`komorebic`](../../komorebic/src/main.rs): the command line. A subcommand that asks
  something of the daemon is one message, sent with `komorebi-client`; `start` runs the
  daemon, `log` follows its log file in [`LOG_DIR`], and the hidden `docgen` writes
  `docs/cli`.
- [`main.rs`](../../komorebi/src/main.rs): the daemon. It connects to KWin, or installs the
  fake with `--fake-backend`, makes the window manager from `komorebi.json` when there is one,
  which binds the socket, loads the desktop, gives the monitors their configuration, asks for the
  borders and tiles, starts the threads that listen on the socket, handle events and take the
  notifications of the monitors, and waits to be stopped.
- [`nixos-module.nix`]: the NixOS module, which installs komorebi and runs the daemon as a
  systemd user unit of every Plasma session.

The handle is a process-wide singleton so that a window can be a small `Copy` value
that carries only its id, and ask the backend for what it needs. A test replaces it for
its own thread with [`with_backend`], which puts the previous one back when the test is
done, also if it panics.

## Traits and roles

**[`Backend`] is the compositor.** It is implemented once for each compositor and once for
the fake. The window manager is its only caller, through [`backend`]. The contract:

- Queries (`windows`, `window`, `foreground_window`, `cursor_pos`) answer from the
  backend's own table and never wait for the compositor, except the KWin backend's
  `cursor_pos`, which waits up to 250 ms for the bridge. `monitors` may fail.
- A command returns once the compositor has accepted it, not once the client has acted on
  it. The frame a window ends up with is what `window_rect` says afterwards, because a
  client may refuse a size.
- A command about a window that does not exist, or is no longer alive, is an error. It
  never panics. The KWin backend knows a closed window for a minute after it closed, and
  sends its commands to the bridge, which reports that it could not carry them out.
- Workspace `i` is the compositor's desktop `i`, and each monitor shows one
  (`switch_workspace`, `set_window_workspace`, `window_workspace`, `current_workspaces`). A
  backend asked for a workspace that has no desktop makes the desktops up to it
  (`ensure_workspaces`). The compositor shows and hides the windows of the desktops, and a
  backend reports a switch or a move it did not make as an event.
- A hidden window (`hide`) is out of sight, alive, not minimized, and on the workspace it was
  on until `restore`: `window_workspace` still names that workspace, and
  `set_window_workspace` changes where it comes back to, not where it is hidden. Only the back of
  a stack and the containers behind a monocle are hidden: nothing is hidden to leave a
  workspace.
- The look is a request (`apply_look`): a backend asks the compositor to draw it and answers
  whether borders are being drawn, and one that draws nothing answers false, which is the default.
  It does nothing when it is asked for the look it applied last.
- `shutdown`, `is_window`, `window_rect` and `monitor_from_point` have defaults, written in
  terms of the queries. An implementor should not need to override them, except `shutdown`
  when it created something in the compositor that has to be given up. `drag_origin` and
  `drag_end` have defaults that keep nothing; a backend whose frames change during a drag and
  after it, as KWin's do, overrides them.

## What is guaranteed, and by what

| Rule | Enforced by | Proof | Escape hatch |
|---|---|---|---|
| A backend implements every query and command but `maximize` | type system: the methods have no defaults, except `maximize`, which does nothing until a backend implements it | `compile_fail,E0046` on [`Backend`] | none |
| A backend can be shared between threads | type system: `Backend: Send + Sync + 'static` | `compile_fail,E0277` on [`Backend`] | none |
| The window manager asks for a backend that was never installed | runtime error: [`backend`] panics, naming [`set_backend`] and [`with_backend`] | `# Panics` on [`backend`] | none |
| A test's backend does not outlive the test | framework path: [`with_backend`] restores the previous one on drop | `with_backend_puts_the_previous_backend_back_when_the_closure_panics` | none |
| A command about a missing window is an error, not a panic | test | `a_command_about_a_window_nobody_opened_is_an_error`, `a_command_about_a_closed_window_is_an_error` and `hiding_or_restoring_a_window_nobody_opened_is_an_error` against the fake, `a_command_about_a_window_the_table_does_not_know_is_an_error_and_sends_nothing` against the KWin backend | none |
| A locked container keeps its index | framework path: a [`Workspace`] inserts, removes and swaps its containers through `LockableSequence` | `test_locked_containers_with_new_window`, `test_locked_containers_remove_window`, `a_window_that_opens_does_not_push_a_locked_container_from_its_index` | `containers_mut()` is the `VecDeque` itself |
| A container in monocle goes back to the index it came from, and the tiles come back as they were resized | framework path: [`Workspace::new_monocle_container`] keeps the index and [`Workspace::reintegrate_monocle_container`] inserts at it, and [`Workspace::update`] does not shorten the resize adjustments while there is a monocle container | `test_toggle_monocle`, `a_monocle_goes_back_to_its_index_even_when_a_window_opens_meanwhile`, `a_tile_that_was_resized_is_the_size_it_was_after_a_monocle` | none |
| The window in monocle keeps the focus | framework path: `handle_event` gives the focus back to the monocle window on a `FocusChange`, and [`WindowManager::update_focused_workspace`] focuses it | `a_window_that_takes_the_focus_from_the_monocle_is_made_to_give_it_back` | none |
| What is about the tiles does nothing while a window is in monocle | framework path: [`WindowManager::move_container_in_direction`] and [`WindowManager::move_container_in_cycle_direction`] bail, and [`WindowManager::toggle_float`] returns, when the window in front is in monocle | `what_is_about_the_tiles_is_refused_or_ignored_while_a_monocle_is_on` | none |
| A focus that crosses to a monitor in monocle gives its monocle window the focus, and a container moved or sent to a workspace in monocle turns the monocle off | framework path: the `None` arm of [`WindowManager::focus_container_in_direction`], [`WindowManager::move_container_in_direction`], [`WindowManager::move_container_to_monitor`] and [`Monitor::move_container_to_workspace`] | `focusing_towards_a_monitor_in_monocle_gives_the_focus_to_its_monocle_window`, `a_container_moved_to_a_monitor_in_monocle_turns_the_monocle_off_there`, `a_container_sent_to_a_workspace_in_monocle_turns_the_monocle_off_there` | none |
| A window in monocle that closes takes the monocle with it | framework path: [`Workspace::remove_window`] looks in the monocle container, which the index of managed windows lists | `closing_the_window_in_monocle_tiles_the_others_again` | none |
| In a real KWin, the window in monocle fills the work area and goes back to its tile | VM test | `vm-core-e2e` ("in monocle the focused window fills the work area", "toggling back puts it on its tile") | none |
| A clean stop, and the next start after a crash, bring back the windows a monocle hid | VM test | `vm-core-e2e` ("and every window is on a workspace's desktop", "after a crash and a restart a monocle still hides the other window") | none |
| A maximized window goes back in a container of its own at the index it came from, and the tiles are where they were | framework path: [`Workspace::new_maximized_window`] keeps the index and [`Workspace::reintegrate_maximized_window`] inserts at it, after asking the backend to restore the window, and nothing else moves in between | `toggle_maximize_takes_the_window_out_of_the_layout_and_back`, `maximizing_works_in_every_layout`, `a_window_goes_back_in_a_container_of_its_own_at_the_index_it_came_from` | none |
| What is about the tiles does nothing while a window is maximized | framework path: `is_layout_command` in [`WindowManager::process_command`] drops the message before it is handled | `while_a_window_is_maximized_what_is_about_the_tiles_does_nothing` | none |
| A window stays maximized through a retile | framework path: [`Workspace::update`] asks the backend to maximize it again, and moves no container | `a_retile_while_a_window_is_maximized_asks_the_compositor_to_maximize_it_again` | none |
| A maximized window that closes takes the maximize with it | framework path: [`Workspace::remove_window`] looks at the maximized window first, which the index of managed windows lists | `a_maximized_window_that_closes_leaves_the_layout_whole` | none |
| In a real KWin, the maximized window fills the work area, is on top, and goes back to its tile | VM test | `vm-features` ("the focused window fills the work area", "and is the one on top", "toggled back, it is in its tile again") | none |
| The focus, move and resize messages act on the windows of the layer a workspace is on | framework path: [`WindowManager::process_command`] matches on [`Workspace::layer`] for `FocusWindow`, `CycleFocusWindow` and `MoveWindow`, [`WindowManager::resize_window`] for the resize messages, and `PreselectDirection` checks it | `focusing_in_a_direction_on_the_floating_layer_goes_to_the_nearest_floating_window`, `moving_on_the_floating_layer_moves_the_floating_window_by_the_resize_delta`, `resizing_on_the_floating_layer_changes_the_frame_of_the_floating_window`, `a_direction_to_preselect_is_ignored_on_the_floating_layer`, `focusing_a_floating_window_towards_a_monitor_crosses_to_it_and_to_its_monocle_window` | none |
| The layer follows the window that has the focus | framework path: `handle_event` sets [`Workspace::layer`] on a `FocusChange`, a `Show` and [`WindowManager::toggle_float`], and [`Monitor::move_container_to_workspace`] on the workspace a window is moved to | `floating_a_window_puts_the_workspace_on_the_floating_layer_and_focusing_a_tile_takes_it_back`, `a_window_sent_to_another_workspace_puts_that_workspace_on_the_layer_it_arrived_on` | none |
| A window that opens on the floating layer floats only when its floating layer behaviour says so | framework path: [`WindowManager::window_management_behaviour`] takes the workspace's behaviour, else its monitor's, else its own, and `handle_event` floats the window on `floating_layer_override` | `the_floating_layer_behaviour_of_the_workspace_wins_over_the_monitors_and_the_window_managers`, `a_window_that_opens_on_the_floating_layer_floats_when_the_behaviour_says_so` | none |
| The windows of the layer a workspace is not on are out of sight | framework path: `ToggleWorkspaceLayer` hides the floating windows when it goes to the tiling layer and restores them when it goes to the floating one | `going_back_to_the_tiles_hides_the_floating_windows_and_going_to_them_shows_them_again` | none |
| Cycling the focus on the floating layer visits every floating window | test | `cycling_the_focus_on_the_floating_layer_goes_round_the_floating_windows_in_order` | none |
| A floating window is never moved out of the work area by `move` | framework path: [`WindowManager::move_floating_window_in_direction`] keeps the frame inside the focused monitor's work area | `moving_on_the_floating_layer_moves_the_floating_window_by_the_resize_delta` | none |
| A window komorebi does not manage is never moved | framework path: `handle_event` asks [`Window::should_manage`] before it acts on any event but a destroy | `dialogs_and_other_non_normal_windows_are_left_alone`, `an_ignore_rule_keeps_a_window_unmanaged` | `ManageRule` |
| A window the user unmanaged stays out of the layout until it is managed again | framework path: `handle_event` checks the list of unmanaged windows before it acts on any event but a removal | `unmanage_takes_the_focused_window_out_until_manage_takes_it_back` | none |
| A paused window manager moves no window | framework path: `handle_event` returns before anything else, and [`read_commands_uds`] drops every message but `TogglePause`, `State`, `GlobalState` and `Stop` | `while_paused_no_event_changes_the_layout_and_manage_takes_in_a_window_it_missed`, `while_paused_only_toggle_pause_state_and_stop_are_handled` | none |
| A destroyed window leaves whichever workspace has it | framework path: the destroy is looked up in the index of managed windows, which is rebuilt at startup and before and after every event | `a_window_that_was_open_before_komorebi_started_is_removed_when_it_closes` | none |
| The daemon does not start without KWin, unless it is told to run against the fake | startup check: [`connect`] fails, and the daemon exits with the error, code 1 | `without_a_session_bus_komorebi_exits_with_an_error_naming_it` | `--fake-backend` |
| One komorebi per session | startup check: the session bus gives `org.komorebi.Bridge` to one connection | none | none |
| A komorebi that cannot connect to KWin leaves the socket of the running one alone | startup order: `main.rs` connects to KWin before [`WindowManager::new`] binds the socket | `without_kwin_komorebi_leaves_the_socket_it_finds_alone` | `--fake-backend` asks no bus, and takes the socket |
| Events reach the window manager in the order KWin raised them | framework path: the `Event` interface is `spawn = false`, so the calls are handled inline, and one channel and one thread carry the events to the window manager | `vm-kwin-events` ("the Show came first") | none |
| No event names a window before the event that announces it | convention in the bridge, which announces a window it has not seen when it is activated; the table shows a window once | `a_new_window_raises_show_and_then_focus_in_that_order`, `announcing_the_same_window_twice_shows_it_once`, `vm-kwin-events` | none |
| A window's id names one window while the daemon runs | framework path: the table numbers each KWin window the first time it sees it, and never gives a number out twice | `ids_are_assigned_once_per_window_and_survive_a_new_snapshot`, `tombstones_are_dropped_after_a_while_and_their_ids_are_not_reused` | none |
| A backend never waits for the window manager | framework path: an event that does not fit in the channel (20 waiting) is dropped and logged | none | none |
| Every window is where komorebi asked for it, within the size its client keeps to | VM test | `vm-core-e2e`, `vm-client-geometry` | a client may refuse a size: the frame is what `window_rect` says |
| A retile reaches KWin as one batch | framework path: the answer to `Poll` waits a millisecond after the first command for the others | `vm-latency` | none |
| The window manager sees a frame it asked for at once | framework path: the KWin backend's `set_rect` records it in the table before KWin answers | `a_requested_rect_is_visible_at_once_and_replaced_by_the_real_one` | none |
| A KWin that restarts gets the bridge again, and the windows of the old one leave the layout | framework path: the connection's thread watches `NameOwnerChanged` for `org.kde.KWin`, and the table destroys every window when the name is lost | `when_kwin_goes_away_every_window_it_had_is_destroyed`, `vm-kwin-restart` | none |
| After KWin restarts, the commands go to the new bridge | framework path: a `Poll` held since before KWin last left the bus is answered with nothing, and passes on the wake-up it got | `a_poll_held_by_the_bridge_of_a_kwin_that_has_gone_gets_no_commands`, `vm-kwin-restart` ("a window opened in the third KWin is tiled") | none |
| Messages are handled one at a time, and in order on one connection | framework path: [`read_commands_uds`] reads a connection line by line and handles each message with the window manager locked | `the_messages_on_one_connection_are_handled_in_order` | none |
| A socket left behind by a daemon that did not stop cleanly does not keep the next one from starting | framework path: [`WindowManager::new`] removes the file before it binds | `a_socket_file_left_behind_is_replaced` | none |
| A daemon that is told to stop leaves no socket behind | framework path: [`WindowManager::stop`] removes it before it exits | `the_daemon_answers_on_its_socket_and_stops_when_it_is_told_to` | `SIGKILL` |
| A container moved onto a locked index is locked in its place, and the lock leaves the container that moved away | framework path: [`Workspace::swap_containers`] swaps through `LockableSequence`, which keeps the lock with the index | `test_swap_respecting_locks_various_cases`, `a_lock_stays_with_its_index_when_a_window_is_moved_onto_it` | `containers_mut()` is the `VecDeque` itself |
| A window komorebi puts off the screen stays there | framework path: the bridge asks again for the position of a window KWin pulled back after a `geo` command, for a second, three times at most | `a window KWin pulls back from where it was asked to be is asked for the position again`, `a window that cannot go where it was asked is asked again three times at most`, `vm-scrolling` | a window that cannot go where it was asked is left where KWin put it |
| A window dragged onto the tile of another swaps places with it, and a window let go of elsewhere goes back to its tile | framework path: `handle_event`'s `MoveEnd` swaps the focused container with the one under the pointer through [`Workspace::swap_containers`], and tiles the workspace again | `dragging_a_window_onto_another_swaps_them`, `a_window_let_go_of_where_there_is_no_tile_goes_back_to_its_own` | a frame that is not as wide and as tall as its tile is not taken for a move, and stays where it was let go |
| A floating window dragged onto a tile takes nothing from it | framework path: `MoveEnd` acts only on a window that is in a container ([`Workspace::contains_managed_window`]) | `a_floating_window_dragged_onto_a_tile_takes_nothing_from_it` | none |
| A window let go of on another monitor goes there, in the place of the container under the pointer | framework path: `MoveEnd` sees that the monitor under the pointer is not the one the drag began on, and hands the window to [`WindowManager::transfer_window`] without comparing its frame with its tile | `a_window_let_go_of_on_another_monitor_goes_to_that_monitor`, `a_window_let_go_of_on_a_monitor_with_nothing_on_it_goes_there`, `a_floating_window_let_go_of_on_another_monitor_is_one_of_the_floating_windows_there` | a floating window that is the only window of its workspace is not noticed to have moved |
| With the window container behavior `Append` a window let go of on a tile joins its container, and with the float override on it floats where it was let go of | framework path: `MoveEnd` reads [`WindowManager::window_management_behaviour`] for the focused workspace | `with_append_a_window_let_go_of_on_a_tile_joins_the_container_of_that_tile`, `with_the_float_override_a_window_let_go_of_on_a_tile_floats_where_it_was_let_go_of` | none |
| The bridge leaves a window the user has taken hold of where the user puts it | framework path: the bridge forgets the position it was asking again for when a drag of the window starts | `a window the user has taken hold of is not asked again for the position komorebi gave it` | none |
| A drag of an edge resizes the tile of the window that was dragged, by what the pointer moved the edge, and moves no other edge | framework path: `ResizeEnd` compares each edge with the frame the drag began with ([`Table::drag_origin`]) and resizes the dragged window's container | `resizing_a_tile_by_hand_moves_the_split`, `a_drag_is_measured_from_where_the_window_was_not_from_its_tile`, `the_window_that_was_dragged_is_the_one_resized_not_the_focused_one`, `a_corner_resizes_both_of_its_edges`, `vm-drag-resize` | none |
| The end of a resize is where the user took the edge, not the frame KWin has then, or reports a moment later | framework path: the bridge sends the frame of the last step as `requested`, the table keeps it for a resize apart from the window's frame ([`Table::drag_end`]), which the frame events that follow the end do not reach, and `ResizeEnd` reads it ([`Backend::drag_end`]) | `the_end_of_a_resize_is_where_the_user_took_it_not_where_the_frame_had_got_to`, `a_frame_that_follows_the_end_of_a_resize_does_not_change_where_the_user_took_it`, `the_end_of_a_resize_is_where_the_user_took_the_edge_when_the_frame_has_not_got_there`, `a drag is reported when the user takes hold of a window and when they let go`, `vm-drag-resize` | a drag with no step ends at the frame |
| The window whose edge is being dragged is not moved until it is let go | framework path: [`Window::set_position`] returns without a command for a window in the list [`live_resize_begins`] adds it to, whatever tiles the workspace | `the_neighbours_follow_a_drag_while_it_is_going_on_and_the_dragged_window_is_left_alone`, `a_window_opening_part_way_through_a_drag_does_not_break_it` | none |
| A drag ends the same with its steps as without them, and one taken back puts the neighbors back | framework path: every step and the end start from the layout kept at the start ([`LiveResize`]) | `a_drag_has_the_same_result_with_the_steps_as_without_them`, `a_drag_that_is_taken_back_puts_the_neighbours_where_they_were`, `vm-live-resize` | none |
| A step of a drag never waits behind another step | framework path: the bridge sends one every 16 ms at most, and [`send_notification`] keeps at most one waiting | `the steps of a resize are sent at most every 16 ms, and the last of a burst is not lost`, `a step waiting when the user lets go is not sent after the end` | none |
| A dragged edge with no neighbor puts the window back on its tile | framework path: `ResizeEnd` tiles the workspace again when the frame changed | `dragging_an_edge_that_has_no_neighbour_puts_the_window_back`, `vm-drag-resize` | none |
| Only a tile is resized by dragging: the window of a stack resizes the tile of the stack, and a floating window or the window of a monocle is left as the user made it | framework path: `ResizeEnd` looks for the container of the dragged window among the workspace's containers ([`Workspace::container_idx_for_window`]), which leaves out the floating windows and the monocle container, and does nothing when there is none | `the_edge_of_a_stack_is_the_edge_of_its_tile`, `a_floating_window_dragged_by_its_edge_is_left_as_the_user_made_it`, `the_window_of_a_monocle_dragged_by_its_edge_is_left_as_the_user_made_it` | none |
| A resize leaves no tile smaller than a tenth of the work area, or than it was | framework path: [`WindowManager::resize_window`] calculates the tiles for the adjustment, and cuts the adjustment down until they all fit | `a_resize_leaves_every_tile_about_a_tenth_of_the_work_area_wide_at_least`, `a_drag_further_than_the_neighbour_can_give_goes_as_far_as_it_can`, `shrinking_a_tile_by_more_than_it_can_is_granted_as_far_as_it_goes` | the paddings are taken off afterwards, so a tile can end up a little smaller |
| The offset of a workspace wins over its monitor's, which wins over the window manager's | framework path: [`Monitor::update_workspace_globals`] gives the workspace the monitor's offset or else the window manager's, and [`Workspace::update`] takes its own before that | `the_workspaces_offset_wins_over_the_monitors_which_wins_over_the_global_one` | none |
| A workspace whose tiling is off moves no window | framework path: [`Workspace::update`] returns before the layout when [`Workspace::tile`] is false | `with_tiling_off_no_window_is_moved_until_it_is_back_on` | none |
| komorebi hides no window to leave a workspace | framework path: showing a workspace is one request to the compositor ([`Backend::switch_workspace`]), which shows and hides the windows of its desktops | `switching_workspace_asks_the_compositor_to_show_the_other_desktop`, `vm-workspace-switch` ("KWin shows the desktop, komorebi hides nothing") | none |
| Showing a workspace on one monitor leaves the other monitors as they are | KWin's per-output virtual desktops, which [`connect`] turns on | `showing_a_workspace_switches_that_output_only`, `vm-kwin-contract` ("the other keeps its own") | a `kwinrc` komorebi cannot write: every monitor switches |
| A window is on its new workspace's desktop before the desktop is shown or the window focused | framework path: [`Monitor::load_focused_workspace`] puts every window on its desktop first | `moving_a_window_to_another_workspace_puts_it_on_the_desktop_before_showing_it` | none |
| A workspace switch or a window move made by something else is followed, and answered with no command | framework path: the table reports what it did not send as a `WorkspaceChange` or a `WorkspaceMove`, and [`WindowManager::adopt_workspace_change`] asks the compositor for nothing | `a_workspace_switch_by_someone_else_is_followed_not_undone`, `a_window_moved_to_another_desktop_by_someone_else_changes_workspace`, `another_party_switching_a_monitor_is_a_workspace_change`, `vm-workspace-switch` ("nothing is flip-flopping") | none |
| komorebi's own switch or move, reported back by KWin, changes nothing | framework path: the table records a switch and a move when it makes their commands | `the_compositor_reporting_komorebis_own_switch_changes_nothing`, `komorebis_own_move_coming_back_as_an_event_moves_nothing`, `komorebi_switching_a_monitor_comes_back_as_a_change_to_what_it_already_knows` | none |
| The user's `kwinrc` gets back the value komorebi changed, also after a crash | framework path: [`Kwinrc`] records the first value of a key in a backup file, and the backend's `shutdown` puts it back | `what_komorebi_changed_is_put_back_exactly_and_what_it_added_is_removed`, `a_backup_left_by_a_crash_keeps_the_values_from_before_the_first_run`, `vm-workspace-switch` ("back as they were") | `SIGKILL`: the next run puts it back when it stops |
| A workspace is closed only when it has no window and no name and is not the monitor's last | framework path: the `CloseWorkspace` arm of [`WindowManager::process_command`] checks all three | `new_workspace_adds_one_and_close_workspace_removes_it_when_it_is_empty_and_unnamed` | none |
| The focus and a move at the edge of a monitor go to the monitor on that side, and fail only when there is none | framework path: the `None` arms of [`WindowManager::focus_container_in_direction`] and [`WindowManager::move_container_in_direction`] | `the_focus_crosses_to_the_monitor_on_that_side`, `a_move_at_the_edge_of_a_monitor_swaps_with_the_window_on_the_next_one_by_default`, `focus_towards_a_side_with_no_window_is_an_error_and_changes_nothing` | `NoOp` keeps a move on its monitor |
| A window shown or focused on another monitor focuses that monitor, and nothing else does | framework path: `handle_event` focuses the monitor of a `Show` or `FocusChange` before it acts on it | `a_window_that_opens_on_the_monitor_that_is_not_focused_focuses_it`, `a_scrolling_strip_on_the_next_monitor_over_does_not_take_focus_with_it` | none |
| Only the window in front of a stack is in sight | framework path: [`Container::add_window`] and [`Container::load_focused_window`] hide every window of the container but the focused one, and every operation that changes the front ends with the call | `a_window_added_to_a_container_is_in_front_and_the_others_are_hidden`, `loading_the_focused_window_shows_it_and_hides_the_rest`, `stacking_puts_two_windows_in_one_container_and_hides_the_one_behind`, `vm-stacks` ("exactly one window is on it") | none |
| A hidden window is still on its workspace, and is not reported as moved | framework path: the table keeps the desktop a window came from, and a move to the parking desktop is its own | `parking_a_window_hides_it_without_unmanaging_it`, `komorebis_own_move_and_its_park_and_restore_raise_nothing_new`, `a_window_is_put_on_a_workspace_by_putting_it_on_its_desktop` | none |
| What the compositor reports about a window komorebi hid is not taken for the user's doing | framework path: [`Window::hide`] records the window in [`HIDDEN_WINDOWS`] before it asks the backend, and the `Minimize` arm of `handle_event` checks it | `a_minimize_komorebi_asked_for_is_not_mistaken_for_the_user`, `a_minimize_the_user_asked_for_takes_the_window_out_of_the_layout` | none |
| While a window is in monocle the windows of the other containers are hidden, and they are shown again when it is turned off | framework path: [`WindowManager::monocle_on`], [`WindowManager::cycle_monocle`] and [`WindowManager::monocle_off`] hide and restore the containers, and [`Workspace::remove_window`] restores them when the window in monocle closes | `a_monocle_hides_the_other_windows_until_it_is_turned_off`, `a_window_in_monocle_that_leaves_shows_the_containers_behind_it`, `the_back_of_a_stack_stays_hidden_in_monocle_and_after_it`, `vm-stacks` ("the window in monocle fills the work area and the other one is out of sight") | none |
| The window the compositor focuses in a stack comes to the front | framework path: the `FocusChange` arm of `handle_event` focuses the container by the window, which loads it ([`Workspace::focus_container_by_window`]) | `focusing_a_hidden_window_of_a_stack_brings_it_to_the_front`, `the_window_the_user_focuses_in_the_back_of_a_stack_comes_to_the_front` | none |
| Cycling a stack changes which window is in front and nothing else | framework path: [`Container::load_focused_window`] shows the focused window and hides the rest; a cycle by index only swaps two places | `cycling_the_stack_brings_the_next_window_to_the_front_and_hides_the_one_that_was`, `cycling_the_index_moves_the_front_window_along_the_stack_and_keeps_it_in_front`, `focus_stack_window_brings_the_window_at_an_index_to_the_front`, `vm-stacks` ("cycle the stack") | none |
| A stack with one window cannot be cycled, and an index it lacks is refused | runtime error: the window manager's functions return it before they change anything | `cycling_a_window_that_is_alone_is_an_error`, `focus_stack_window_refuses_an_index_the_stack_does_not_have` | none |
| Closing the window in front of a stack brings the next one forward | framework path: [`Workspace::remove_window`] shows the container's new front window and focuses it | `closing_the_window_in_front_of_a_stack_brings_the_next_one_forward`, `vm-stacks` ("closing the window in view") | none |
| The back of a stack stays hidden when its workspace is shown again | framework path: [`Workspace::restore`] restores the front window of each container and no other | `the_back_of_a_stack_stays_hidden_across_a_workspace_round_trip`, `vm-stacks` ("a workspace round trip") | none |
| A window is never sent to a parking desktop that is not there | framework path: [`Table::hide_commands`] asks for a new one unless KWin lists the one it made | `a_parking_desktop_that_has_gone_is_made_again_not_sent_windows` | none |
| A monitor raised onto the parking desktop is sent back | framework path: the table sends the monitor back to the desktop it showed before | `following_a_hidden_window_to_the_parking_desktop_sends_that_output_back` | none |
| A clean stop leaves no window hidden and no parking desktop | framework path: [`WindowManager::stop`] and the signal handler restore every hidden window, and the backend's `shutdown` removes the desktop after the restoring commands have gone out | `restoring_every_window_brings_back_the_hidden_ones_unless_it_is_told_to_ignore_that`, `vm-stacks` ("a clean stop puts every window back") | `SIGKILL`, and `StopIgnoreRestore`, which restores nothing |
| A parking desktop a dead daemon left is swept by the next one, and its windows go home | startup check: the first snapshot marks it stale, sends its windows to the first workspace's desktop, and the backend removes it | `a_parking_desktop_left_by_a_crashed_run_is_swept`, `a_stale_parking_desktop_is_not_the_one_windows_are_hidden_on`, `vm-stacks` ("a crash leaves a parking desktop") | none |
| A monitor that changes size has the windows of the workspace in front tiled in the size it has now | framework path: the table reports a changed size or work area as a `Resize`, and the reconciliator reads the monitors again and tiles the focused monitor | `plugging_in_a_monitor_is_a_connection_change_and_a_new_panel_is_a_resize`, `a_change_of_resolution_is_tiled_again`, `vm-hotplug` ("tiled again inside the monitor as it is now") | `Retile` tiles every monitor |
| The outputs are sent when they are not what the bridge last sent, and the room a panel leaves is found within a second | convention in the bridge: it sends after `screensChanged`, after a dock window opens, closes or moves, and in its watchdog, which runs every second | `a change of the outputs is sent as the screens, once, and the panel is looked at again`, `a panel that opens, moves or closes has the area of the outputs looked at again`, `the outputs are looked at once a second, which finds a panel that starts after the bridge` | none |
| The windows of a monitor that is unplugged are tiled on the monitors that are left | framework path: [`reconcile_display_change`] has [`WindowManager::evacuate_monitor`] move each container and floating window to the monitor that holds it, before it removes the monitor | `the_windows_of_a_monitor_that_goes_are_tiled_on_the_one_that_is_left`, `vm-hotplug` ("tiled inside the screen that is left") | none |
| A stack moves with its monitor as a stack | framework path: [`WindowManager::evacuate_monitor`] moves whole containers | `a_stack_goes_with_the_monitor_as_a_stack` | none |
| A monocle or a maximized window of a monitor that goes is not lost | framework path: [`WindowManager::evacuate_monitor`] takes both out of the workspace and puts each in a container on the monitor that is left | `a_monocle_of_a_monitor_that_goes_comes_back_as_a_container_with_the_windows_it_hid`, `a_maximized_window_of_a_monitor_that_goes_is_not_lost` | none |
| A monitor that is plugged in again has the settings it had, and none of the windows it had | framework path: [`reconcile_display_change`] keeps the monitor in a cache when it goes, and applies it, less the windows the window manager has elsewhere, when a monitor with its serial number id comes | `a_monitor_that_comes_back_gets_what_was_kept_of_it_and_none_of_the_windows_it_had` | none |
| A monitor komorebi has not seen gets workspaces of its own | framework path: [`load_monitor_information`] adds the monitors the window manager does not have | `a_monitor_that_was_never_there_gets_windows_of_its_own` | none |
| When KWin reports no output, the window manager keeps the monitors it has | framework path: [`reconcile_display_change`] returns before it removes any | `a_desktop_that_reports_no_monitor_is_left_as_it_was` | none |
| A monitor is only removed once its windows are on the monitors that are left | framework path: [`reconcile_display_change`] evacuates every monitor that went before it removes any | `the_windows_of_a_monitor_that_goes_are_tiled_on_the_one_that_is_left` | none |
| A subscriber that wants only changes of the state is sent every change of the monitors | framework path: [`notify_subscribers`] treats a monitor notification as an override of the filter | `a_change_of_the_monitors_is_sent_to_a_subscriber_that_filters_state_changes_too` | none |
| Moving the focus moves no window | test | `focus_gives_the_focus_to_the_window_on_that_side_and_moves_nothing`, `vm-core-e2e` ("moving the focus moved no window") | none |
| A subscriber that is gone is dropped, not retried | test | `a_subscriber_that_is_gone_is_dropped_and_not_tried_again` | none |
| The bridge holds no window manager logic | convention, with every decision about an event in the table, which the `kwin::state` unit tests pin | the unit tests in `komorebi/src/kwin/state.rs` | none |
| What the bridge sends is what the table reads | type checker: the JSDoc types of the messages in [`bridge.js`]; tests: the events of [`fixtures`] are what the bridge's tests check it sends and what the table's tests feed it | `what the bridge sends for a session is what the daemon's tests read`, `the_bridges_events_for_a_session_are_the_window_events_komorebi_expects` | none |
| What the backend sends is what the bridge carries out | tests: the commands of [`fixtures`] are what the backend's tests check it sends and what the bridge's tests answer it with, checking what KWin is asked to do for each | `the_commands_of_a_session_go_to_the_bridge_as_the_bridges_tests_answer_it`, `what the bridge sends for a session is what the daemon's tests read`, `a command for a window KWin no longer has is given back, and the rest are carried out` | none |
| Everything the bridge sends over D-Bus is one string | type checker: [`kwin-api.d.ts`] gives `callDBus` one string argument | `tsc`, `every call goes to the daemon's names, with one JSON string` | none |
| The bridge uses nothing a KWin script does not have | type checker: the library is ECMAScript 2016 alone, and KWin's API is what [`kwin-api.d.ts`] declares | `tsc` | a declaration KWin does not match: the VM tests run the bridge in KWin |
| A border takes room around the windows only while the compositor draws it | framework path: [`border_manager::send_notification`] keeps the backend's answer in [`BORDER_DRAWN`], which [`Monitor::update_workspace_globals`] reads | `a_border_the_compositor_draws_takes_room_around_each_window_and_none_is_taken_without_one`, `a_look_is_a_command_once_and_says_whether_borders_are_drawn` | none |
| The compositor is asked for the look after every event, every message and every retile, and only a changed look reaches it | framework path: [`WindowManager::process_event`], [`WindowManager::process_command`] and [`WindowManager::retile_all`] call [`border_manager::send_notification`], and a backend compares with the look it applied last | `the_border_messages_set_the_border_and_the_compositor_is_asked_for_it`, `a_look_is_a_command_once_and_says_whether_borders_are_drawn` | the same look applied twice by the KWin backend is not tested |
| No outline is drawn inside a window, and a border is never thicker than the effect can draw | framework path: [`kwin::effects`](../../komorebi/src/kwin/effects.rs) sets every inner outline to 0 and clamps the width to 20 | `the_border_is_the_outer_outline_and_nothing_is_drawn_inside_the_window`, `a_border_thicker_than_the_effect_can_draw_is_the_thickest_it_can`, `vm-look` | none |
| Every window has the border color of what it is to the layout, and a window whose kind changes has the new one at once | framework path: [`border_manager::update_colours`] is called after every event and every message, from [`border_manager::window_kinds`], and the backend sends the colors it did not send last time | `the_focused_window_has_the_focus_colour_and_the_others_do_not`, `a_locked_container_that_is_not_focused_is_marked`, `a_stack_has_its_own_colour_when_it_has_the_focus`, `a_monocled_window_has_the_monocle_colour`, `a_floating_window_has_the_floating_colour_while_it_has_the_focus`, `border_colours_are_a_command_only_when_they_change`, `vm-features` (section C) | the stock effect: two colors for every window |
| With borders off no window has a color | framework path: [`border_manager::update_colours`] tells the backend an empty list when `BORDER_ENABLED` is false | `with_borders_off_no_window_has_a_colour` | none |
| The settings of one kind of animation win over the global ones, and a global setting clears them | framework path: the arms of [`WindowManager::process_command`] for `Animation`, `AnimationDuration` and `AnimationStyle`, and [`animation::movement_animation`] and [`animation::movement_style`], which read the kind's setting before the global one | `the_animation_messages_set_the_animation_and_the_compositor_is_asked_for_it` | none |
| A command that changes a stack is carried out with the animation off, and the animation is on again after it | framework path: the arms of [`WindowManager::process_command`] for the stack messages swap `ANIMATION_ENABLED_GLOBAL` for false and put the value back | `the_animation_is_on_again_after_a_command_that_changes_a_stack` | none |
| The `animation` key of the file is the animation settings, and a file without it leaves them | framework path: `StaticConfig::apply_globals` sets them only when the key is there, and `duration` and `style` only when the key has one | `the_animation_key_of_the_file_is_the_animation_settings` | none |
| Every style is a curve Qt has | test: [`AnimationStyle::qt_curve`] is a `match` of every style, and the test checks each against its name without the "Ease" | `every_style_is_a_curve_qt_has`, the doctest of `qt_curve`, `vm-features` (section D: two curves are in different places at the same moment) | a cubic Bézier is an ease out |
| Only the windows the rules make see-through are, and only while transparency is on | framework path: [`transparency_manager::apply`] asks [`transparency_manager::transparent_windows`] and sends the difference from [`WindowManager::opacity_applied`] | `unfocused_windows_are_transparent_and_the_focused_one_is_not`, `turning_transparency_off_makes_everything_opaque_again`, `a_monocled_window_is_not_transparent`, `windows_the_rules_ignore_keep_their_opacity`, `vm-features` (section B) | none |
| The `transparency` keys of the file are the settings, and a key the file leaves out has the default | framework path: `StaticConfig::apply_globals` stores `transparency` and `transparency_alpha` whether the file has them or not, and adds the ignore rules to `TRANSPARENCY_BLACKLIST` | `the_transparency_keys_of_the_file_are_the_transparency_settings` | none |
| A theme gives every kind of border a color, the one it names or the theme's default | framework path: [`theme_manager::send_notification`] stores a color for each of the six kinds, from the theme's own defaults for the ones the message does not name | `a_named_theme_colours_every_kind_of_border` | none |
| The `border_colours` of the file are the border colors, and a theme in the file wins over them | framework path: `StaticConfig::apply_globals` stores each color the file names, and then calls [`theme_manager::send_notification`] for the `theme` | `the_colour_and_theme_keys_of_the_file_are_the_border_colours` | none |
| A picture's palette is made again when the picture changes, and is not mistaken for another picture's | framework path: [`theme_manager::palette_file`] names the file by a hash of the picture's path, size and time of last change, and the variant | the doctest of `palette_file` | the hash is not a proof of identity |
| A workspace that comes into view has its wallpaper set, its own before its monitor's, however it came into view; none is touched for a workspace and a monitor without one | framework path: [`Workspace::restore`], [`WindowManager::adopt_workspace_change`] and [`WindowManager::retile_all`] call [`Workspace::apply_wallpaper`], which takes `self.wallpaper` before the monitor's | `a_wallpaper_is_set_when_its_workspace_comes_into_view_by_whoever_brings_it`, `no_wallpaper_is_touched_that_was_not_asked_for`, `vm-wallpaper` (sections A and B) | none |
| The borders have the colors of the wallpaper in front, and keep theirs when it asks for no theme or has no palette | framework path: [`Workspace::apply_wallpaper`] sends a theme only for a wallpaper that does not say `generate_theme: false` and has a palette | `the_borders_take_their_colours_from_the_wallpaper_and_follow_it`, `a_wallpaper_that_asks_for_no_theme_leaves_the_borders_alone`, `a_wallpaper_that_is_not_a_picture_still_sets_and_does_not_break_the_window_manager`, `theme_options_choose_the_variant_and_the_colour_each_border_takes`, `vm-wallpaper` (section C) | none |
| A wallpaper the screen shows already is not set again, and one the user changed by hand is set back | framework path: [`kwin::wallpaper`]`::apply` compares what the shell answers with the picture, the fill and the plugin | `vm-wallpaper` (section D) | the comparison alone has no test |
| Any path is a URL the shell can read, and the name of an output cannot end the string it is in in the shell's script | framework path: `kwin::wallpaper::file_url` percent-encodes every byte but a few ASCII ones, and the script writes the name as a JSON string | `a_path_becomes_a_url_the_shell_can_read`, `the_name_of_an_output_cannot_end_the_string_it_is_in`, `vm-wallpaper` (a path with a space in it) | none |
| Setting a wallpaper never holds up the window manager | framework path: [`Backend::set_wallpaper`] of the KWin backend notes the wish and spawns the request on the runtime | none | the monitor and the path are checked before it returns |
| The KWin backend refuses a wallpaper for a monitor it does not have and for a path that is no file | framework path: `set_wallpaper` of the KWin backend looks the monitor up in its table and checks the path | `a_wallpaper_is_refused_for_a_monitor_kwin_lacks_and_for_a_path_that_is_no_file` | none |
| A window komorebi made see-through is opaque again when komorebi exits | framework path: [`WindowManager::stop`] and `main.rs` call [`transparency_manager::restore`] | `what_komorebi_made_see_through_is_opaque_again_when_it_exits` | `SIGKILL`: the windows stay as they were drawn |
| What the backend sends for an opacity is what the bridge sets | tests: the `opacity` command of [`fixtures`] is what the backend's test sends and what the bridge's test answers with, checking the window's `opacity` | `the_commands_of_a_session_go_to_the_bridge_as_the_bridges_tests_answer_it`, `what the bridge sends for a session is what the daemon's tests read`, `a window is given the opacity it is asked for, and one KWin has not got is given back` | none |
| The user's focus policy is put back when focus follows mouse is turned off and when komorebi exits | framework path: [`Kwinrc`] records the first value of each key it sets, `set_focus_follows_mouse(false)` puts the two keys back with [`Kwinrc::restore_keys`] and `shutdown` puts back all | `one_key_can_be_put_back_while_the_others_in_its_group_stay_changed`, `what_komorebi_changed_is_put_back_exactly_and_what_it_added_is_removed`, `vm-focus-follows-mouse` | `SIGKILL`: the next run puts it back when it stops |
| Focus follows mouse is the compositor's, whichever implementation is named | framework path: the `FocusFollowsMouse` and `ToggleFocusFollowsMouse` arms ask the backend the same thing for both | `focus_follows_mouse_is_asked_of_the_compositor_and_toggles` | none |
| The `focus_follows_mouse` key of the file turns it on, and a file that leaves it out turns it off | framework path: `StaticConfig::postload` and `StaticConfig::reload` set the window manager's field from the file and ask the backend for it | `the_file_turns_focus_follows_mouse_on_and_a_file_that_leaves_it_out_turns_it_off` | none |
| The window under the pointer has the focus, and komorebi follows | the compositor's focus policy; the window manager follows the focus event as any other | `vm-focus-follows-mouse` (a real pointer over each window) | none |
| The effect komorebi loaded is unloaded, and the user's settings of it are put back, when komorebi stops using it or exits | framework path: the effect's state unloads what komorebi loaded, and [`Kwinrc`] puts the group back | `one_group_can_be_put_back_while_the_others_stay_changed`, `vm-look` | `SIGKILL`: the next run puts the settings back when it stops |
| Queries never block on the compositor | convention only | none | the KWin backend's `cursor_pos` waits up to 250 ms |
| Only the backend module reaches the compositor | convention only | none | none |

The rows enforced by convention are rules nothing checks. A real backend that waits inside a
query breaks one of them, a module that talks to D-Bus directly breaks another, and a bridge
that decides something in JavaScript breaks a third: the bridge's tests check what it sends,
not that it decides nothing.

## One event, end to end

A window is shown, and ends up on a tile:

1. KWin raises `windowAdded`. The bridge sends an `added` event with what KWin says about
   the window, and [`Table::handle`] gives the window an id, records it, and returns a
   [`WindowManagerEvent`]`::Show` carrying the window and the compositor signal it came
   from. The event goes on the channel, and the event thread calls
   [`WindowManager::process_event`], which hands it to `handle_event` and logs how long that
   took. The end-to-end tests build the event themselves and call `process_event`.
2. `handle_event` asks [`Window::should_manage`], which asks the backend's `window(id)`
   whether the window is alive and normal, and then the rules whether it is to be managed. If
   it is not, the event changes nothing. If a float rule matches it, it goes into the
   workspace's floating windows and the steps below do not apply.
3. The index of managed windows is rebuilt from the containers. If the workspace in front
   already has the window, or the index has it on another monitor or workspace, the event
   creates nothing.
4. [`Workspace::new_container_for_window`] puts the window in a new container after the
   focused one, inserted through `LockableSequence` so that a locked container keeps its
   index, and focuses the new container.
5. [`WindowManager::update_focused_workspace`] asks the focused [`Monitor`] to give its
   focused workspace the work area, the padding and the offset ([`WorkspaceGlobals`]),
   and calls [`Workspace::update`].
6. `Workspace::update` asks the layout for one tile per container, clamps each to the work
   area, and calls [`Window::set_position`] for each window, which is the backend's
   `set_rect`. The fake puts the window there at once; the frame a window ends up with is
   what `window_rect` says afterwards. The KWin backend queues a `geo` command for the
   bridge, the bridge sets the window's frame, the client draws at the size it accepts, and
   KWin reports the frame it ended up with as a `geometry` event, which updates the table.
7. If the new container is the only one, the window is given the focus with the backend's
   `focus`, and the pointer follows it (on KWin, through its "Move Mouse to Focus"
   shortcut).
8. The index is rebuilt again, so the next event finds the window.
9. [`notify_subscribers`] sends every subscriber a [`Notification`] of the `Show`, with the
   state that now has the window. A `Show` is sent to a subscriber with
   `filter_state_changes` too, whether or not it changed the state.

## One message, end to end

`komorebic state` asks for the state of the window manager:

1. `komorebic` calls [`send_query`], which connects to `komorebi.sock` in [`DATA_DIR`],
   writes `{"type":"State"}`, and shuts down its side of the connection for writing.
2. The thread that [`listen_for_commands`] started accepts the connection and starts a
   thread for it, which calls [`read_commands_uds`].
3. `read_commands_uds` reads the line, parses it into [`SocketMessage`]`::State`, and locks
   the window manager, waiting up to a second.
4. [`WindowManager::process_command`] makes a [`State`] from the window manager, a copy of
   every monitor with its workspaces, containers and windows. Each window is serialized
   with what the backend reports about it now: its frame, title, executable, class and path.
5. The state is written to the connection as pretty-printed JSON, and the index of managed
   windows is rebuilt, as after every message. The subscribers are sent a notification of
   the `State` message, except those with `filter_state_changes`: it changed nothing.
6. There are no more lines, so `read_commands_uds` returns and the connection is closed.
   `send_query` has read to the end, and returns the JSON, which `komorebic` prints.

## Where to look in the code

- [`komorebi/src/backend/mod.rs`](../../komorebi/src/backend/mod.rs): the trait.
- [`komorebi/src/backend/fake.rs`](../../komorebi/src/backend/fake.rs): the fake and its
  tests.
- [`komorebi/src/core`](../../komorebi/src/core/mod.rs): the vocabulary the rest is written
  in.
- [`komorebi/src/workspace.rs`](../../komorebi/src/workspace.rs): tiling, in
  `Workspace::update`.
- [`komorebi/src/monitor.rs`](../../komorebi/src/monitor.rs): the work area, padding and
  offset a monitor gives the workspace it shows.
- [`komorebi/src/static_config.rs`](../../komorebi/src/static_config.rs): `komorebi.json`.
  [`komorebi/tests/config.rs`](../../komorebi/tests/config.rs) loads files over the fake
  desktop, [`komorebi/tests/config_displays.rs`](../../komorebi/tests/config_displays.rs) one
  with several monitors, [`komorebi/tests/hot_reload.rs`](../../komorebi/tests/hot_reload.rs) the
  daemon following a file, and
  [`komorebi/tests/config_parity.rs`](../../komorebi/tests/config_parity.rs) the files of other
  platforms and the example, which load;
  [`komorebi/tests/replace_configuration.rs`](../../komorebi/tests/replace_configuration.rs)
  the `ReplaceConfiguration` message;
  [`komorebi/tests/workspace_rules.rs`](../../komorebi/tests/workspace_rules.rs) the workspace
  rules; [`komorebi/tests/schemas.rs`](../../komorebi/tests/schemas.rs) the schemas the daemon answers
  with; [`schema.json`](../../schema.json), [`schema.asc.json`](../../schema.asc.json) and
  [`nix/komorebi-options.nix`](../../nix/komorebi-options.nix), which are generated;
  [`nix/tests/default.nix`](../../nix/tests/default.nix) and
  [`nix/tests/komorebi-example.nix`](../../nix/tests/komorebi-example.nix), the check of the options
  and the example it evaluates them against; [`komorebi/tests/asc.rs`](../../komorebi/tests/asc.rs)
  the applications files; [`komorebi/src/core/asc.rs`](../../komorebi/src/core/asc.rs) their
  format.
- [`komorebi/src/process_event.rs`](../../komorebi/src/process_event.rs): what each event
  does, and the thread that handles them.
- [`komorebi/src/process_command.rs`](../../komorebi/src/process_command.rs): the socket, what
  each message does, and the tests that send messages through a real socket.
- [`komorebi-client/src/lib.rs`](../../komorebi-client/src/lib.rs): the client side of the
  socket.
- [`komorebi-client/tests/subscribe.rs`](../../komorebi-client/tests/subscribe.rs):
  subscribers and the notifications they are sent, through real sockets.
- [`komorebic/src/main.rs`](../../komorebic/src/main.rs): the subcommands, and
  [`komorebic/tests/cli.rs`](../../komorebic/tests/cli.rs), what each writes on the socket.
- [`komorebi/src/kwin/mod.rs`](../../komorebi/src/kwin/mod.rs): the KWin backend, its D-Bus
  service and the held call.
- [`komorebi/src/kwin/state.rs`](../../komorebi/src/kwin/state.rs): the table, with the
  shapes of the bridge's events, and its tests.
- [`komorebi/src/kwin/bridge.js`](../../komorebi/src/kwin/bridge.js): the bridge, with the
  types of its messages; [`kwin-api.d.ts`] and
  [`tsconfig.json`](../../komorebi/src/kwin/tsconfig.json), what `tsc` checks it against;
  [`bridge.test.js`], its tests; [`fixtures`], the messages both sides' tests read.
- [`nix/tests/vm/suites/kwin-events`](../../nix/tests/vm/suites/kwin-events/test.py): the
  events of a real KWin, through the daemon.
- [`nix/tests/vm/suites/core-e2e`](../../nix/tests/vm/suites/core-e2e/test.py): the daemon
  tiling a real KWin, checked against what KWin has, with a window in monocle, and read and
  stopped with `komorebic`.
- [`nix/tests/vm/suites/kwin-restart`](../../nix/tests/vm/suites/kwin-restart/test.py): KWin
  restarting under the daemon.
- [`nix/kde-rounded-corners.nix`](../../nix/kde-rounded-corners.nix): the build of the KWin
  effect that draws an outline around each window, with
  [`komorebi-border-colours.patch`](../../nix/kde-rounded-corners/komorebi-border-colours.patch),
  which lets komorebi give each window a color;
  [`nix/kwin-effect-geometry-change.nix`](../../nix/kwin-effect-geometry-change.nix), the
  effect that animates a window going to its place, with
  [`curve.patch`](../../nix/kwin-effect-geometry-change/curve.patch), which makes its easing
  curve a setting; and
  [`nix/tests/effects.nix`](../../nix/tests/effects.nix), the checks of the files each effect
  package installs.
- [`komorebi/tests/borders.rs`](../../komorebi/tests/borders.rs) and
  [`komorebi/tests/border_commands.rs`](../../komorebi/tests/border_commands.rs): the room a drawn
  border takes, and the messages that set the border, against the fake;
  [`komorebi/tests/animation.rs`](../../komorebi/tests/animation.rs), the messages that set the
  animation, [`komorebi/tests/animation_config.rs`](../../komorebi/tests/animation_config.rs), its
  key of the file, and [`komorebi/tests/animation_stack.rs`](../../komorebi/tests/animation_stack.rs),
  the stack commands that turn it off; [`komorebi/tests/themes.rs`](../../komorebi/tests/themes.rs),
  a named theme and [`komorebi/tests/theme_config.rs`](../../komorebi/tests/theme_config.rs), the
  colors and the theme of the file; [`komorebi/tests/focus_follows_mouse.rs`](../../komorebi/tests/focus_follows_mouse.rs),
  focus follows mouse; [`komorebi/tests/transparency.rs`](../../komorebi/tests/transparency.rs)
  and [`komorebi/tests/transparency_config.rs`](../../komorebi/tests/transparency_config.rs),
  transparency and its keys of the file; [`komorebi/tests/border_colours.rs`](../../komorebi/tests/border_colours.rs) and
  [`komorebi/tests/borders_off.rs`](../../komorebi/tests/borders_off.rs), the color of each
  window's border, and none with borders off;
  [`nix/tests/vm/suites/look`](../../nix/tests/vm/suites/look/test.py), the border in a real
  Plasma session, read from the pixels of a screenshot, and
  [`nix/tests/vm/suites/features`](../../nix/tests/vm/suites/features/test.py), the colors of the
  kinds of window; [`nix/tests/vm/suites/focus-follows-mouse`](../../nix/tests/vm/suites/focus-follows-mouse/test.py),
  focus follows mouse with a real pointer, which [`Pointer`](../../nix/tests/vm/lib/komorebi_vm/pointer.py)
  moves from inside the guest; [`komorebi/tests/wallpaper.rs`](../../komorebi/tests/wallpaper.rs), the
  wallpapers and the colors made of them, against the fake; and
  [`nix/tests/vm/suites/wallpaper`](../../nix/tests/vm/suites/wallpaper/test.py), against the
  real Plasma shell.
- [`komorebi/tests/wm_events.rs`](../../komorebi/tests/wm_events.rs): the window manager
  driven end to end against the fake.
- [`komorebi/tests/socket.rs`](../../komorebi/tests/socket.rs): the daemon over its socket,
  from its start to a `Stop`.
- [`komorebi/tests/focus.rs`](../../komorebi/tests/focus.rs),
  [`komorebi/tests/moving.rs`](../../komorebi/tests/moving.rs) and
  [`komorebi/tests/layouts.rs`](../../komorebi/tests/layouts.rs): the focus, move and layout
  commands against the fake;
  [`komorebi/tests/layout_options.rs`](../../komorebi/tests/layout_options.rs) and
  [`komorebi/tests/scrolling.rs`](../../komorebi/tests/scrolling.rs), the layout options and the
  scrolling layout; [`komorebi/tests/resize.rs`](../../komorebi/tests/resize.rs), resizing;
  [`komorebi/tests/promote.rs`](../../komorebi/tests/promote.rs), promoting;
  [`komorebi/tests/float.rs`](../../komorebi/tests/float.rs), floating;
  [`komorebi/tests/lock.rs`](../../komorebi/tests/lock.rs), locking;
  [`komorebi/tests/floating_layer.rs`](../../komorebi/tests/floating_layer.rs), the layers;
  [`komorebi/tests/monocle.rs`](../../komorebi/tests/monocle.rs), the monocle;
  [`komorebi/tests/maximize.rs`](../../komorebi/tests/maximize.rs) and
  [`komorebi/tests/maximize_commands.rs`](../../komorebi/tests/maximize_commands.rs), maximizing;
  [`komorebi/tests/manage.rs`](../../komorebi/tests/manage.rs), minimizing, closing,
  unmanaging and managing the focused window, and pausing;
  [`komorebi/tests/padding.rs`](../../komorebi/tests/padding.rs), the paddings and the work area
  offsets; [`komorebi/tests/rules.rs`](../../komorebi/tests/rules.rs) and
  [`komorebi/tests/rule_commands.rs`](../../komorebi/tests/rule_commands.rs), the rules and the
  messages that add and show them;
  [`komorebi/tests/drag_swap.rs`](../../komorebi/tests/drag_swap.rs), dragging a window onto
  another tile and onto another monitor;
  [`komorebi/tests/drag_resize.rs`](../../komorebi/tests/drag_resize.rs), dragging an edge;
  [`komorebi/tests/live_resize.rs`](../../komorebi/tests/live_resize.rs), the neighbors following
  it.
- [`nix/tests/vm/suites/scrolling`](../../nix/tests/vm/suites/scrolling/test.py): the scrolling
  strip in a real KWin, with its columns out of view off the screen.
- [`nix/tests/vm/suites/features`](../../nix/tests/vm/suites/features/test.py): what is on the
  screen of a real compositing session, read from screenshots.
- [`nix/tests/vm/suites/commands`](../../nix/tests/vm/suites/commands/test.py): every layout,
  and every `komorebic` command, against a real KWin with two outputs.
- [`nix/tests/vm/suites/drag-resize`](../../nix/tests/vm/suites/drag-resize/test.py): edges and
  corners dragged with a pointer in a Plasma session;
  [`nix/tests/vm/suites/live-resize`](../../nix/tests/vm/suites/live-resize/test.py), the
  neighbors read while the edge is held.
- [`komorebi/tests/monitor_resize.rs`](../../komorebi/tests/monitor_resize.rs) and
  [`komorebi/tests/hotplug.rs`](../../komorebi/tests/hotplug.rs): a monitor that changes size,
  and monitors that are unplugged and plugged in, against the fake;
  [`nix/tests/vm/suites/hotplug`](../../nix/tests/vm/suites/hotplug/test.py), both against a real
  KWin with two outputs.
- [`komorebi/tests/workspaces.rs`](../../komorebi/tests/workspaces.rs): workspaces as the
  fake's desktops;
  [`komorebi/tests/workspace_commands.rs`](../../komorebi/tests/workspace_commands.rs), naming,
  cycling and the other workspace commands;
  [`komorebi/tests/monitors.rs`](../../komorebi/tests/monitors.rs), two monitors: crossing from
  one to the other, the monitor commands and `EagerFocus`; [`komorebi/src/kwin/kwinrc.rs`](../../komorebi/src/kwin/kwinrc.rs), the
  `kwinrc` editor and its tests.
- [`komorebi/tests/stacks.rs`](../../komorebi/tests/stacks.rs): stacking, unstacking and the windows
  a stack hides, the behavior of new windows and the float override, against the fake;
  [`nix/tests/vm/suites/stacks`](../../nix/tests/vm/suites/stacks/test.py), the same in a real
  KWin, with the parking desktop, a crash and a stop.
- [`nix/tests/vm/suites/workspace-rules`](../../nix/tests/vm/suites/workspace-rules/test.py):
  workspace rules sending windows to other workspaces of a real KWin, out of sight on the parking
  desktop until the workspace is shown.
- [`nix/tests/vm/suites/workspace-switch`](../../nix/tests/vm/suites/workspace-switch/test.py):
  workspaces as a real KWin's desktops, switched by `komorebic` and by KWin;
  [`nix/tests/vm/suites/kwin-contract`](../../nix/tests/vm/suites/kwin-contract/test.py), the
  behavior of KWin's per-output virtual desktops komorebi relies on, with two outputs and no
  komorebi.
- [`nix/nixos-module.nix`](../../nix/nixos-module.nix): the NixOS module;
  [`nix/tests/nixos-module.nix`](../../nix/tests/nixos-module.nix), its scenarios, evaluated in
  real NixOS systems; and [`nix/tests/vm/suites/module`](../../nix/tests/vm/suites/module/test.py),
  a Plasma session in which the module's unit runs the daemon.

[`nixos-module.nix`]: ../../nix/nixos-module.nix
[`StaticConfig`]: ../../komorebi/src/static_config.rs
[`StaticConfig::preload`]: ../../komorebi/src/static_config.rs
[`StaticConfig::postload`]: ../../komorebi/src/static_config.rs
[`StaticConfig::reload`]: ../../komorebi/src/static_config.rs
[`Workspace::load_static_config`]: ../../komorebi/src/workspace.rs
[`HOME_DIR`]: ../../komorebi/src/lib.rs
[`WORKSPACE_MATCHING_RULES`]: ../../komorebi/src/lib.rs
[`WindowManager::enforce_workspace_rules`]: ../../komorebi/src/window_manager.rs
[`WindowManager::already_moved_window_handles`]: ../../komorebi/src/window_manager.rs
[`Monitor::assign_windows_to_workspaces`]: ../../komorebi/src/monitor.rs
[`LAYOUT_DEFAULTS`]: ../../komorebi/src/lib.rs
[`IGNORE_IDENTIFIERS`]: ../../komorebi/src/lib.rs
[`MANAGE_IDENTIFIERS`]: ../../komorebi/src/lib.rs
[`FLOATING_APPLICATIONS`]: ../../komorebi/src/lib.rs
[`hotwatch`]: https://crates.io/crates/hotwatch
[`WindowManager::init`]: ../../komorebi/src/window_manager.rs
[`Backend`]: ../../komorebi/src/backend/mod.rs
[`WindowInfo`]: ../../komorebi/src/backend/mod.rs
[`MonitorInfo`]: ../../komorebi/src/backend/mod.rs
[`set_backend`]: ../../komorebi/src/backend/mod.rs
[`backend`]: ../../komorebi/src/backend/mod.rs
[`with_backend`]: ../../komorebi/src/backend/mod.rs
[`Look`]: ../../komorebi/src/backend/mod.rs
[`Backend::apply_look`]: ../../komorebi/src/backend/mod.rs
[`border_manager`]: ../../komorebi/src/border_manager/mod.rs
[`border_manager::current_look`]: ../../komorebi/src/border_manager/mod.rs
[`border_manager::send_notification`]: ../../komorebi/src/border_manager/mod.rs
[`BORDER_DRAWN`]: ../../komorebi/src/border_manager/mod.rs
[`animation`]: ../../komorebi/src/animation/mod.rs
[`KomorebiTheme`]: ../../komorebi/src/core/mod.rs
[`theme_manager::send_notification`]: ../../komorebi/src/theme_manager.rs
[`theme_manager::CURRENT_THEME`]: ../../komorebi/src/theme_manager.rs
[`theme_manager::wallpaper_palette`]: ../../komorebi/src/theme_manager.rs
[`theme_manager::palette_file`]: ../../komorebi/src/theme_manager.rs
[`Wallpaper`]: ../../komorebi/src/static_config.rs
[`Workspace::apply_wallpaper`]: ../../komorebi/src/workspace.rs
[`Workspace::restore`]: ../../komorebi/src/workspace.rs
[`Backend::set_wallpaper`]: ../../komorebi/src/backend/mod.rs
[`kwin::wallpaper`]: ../../komorebi/src/kwin/wallpaper.rs
[`komorebi_themes::generate_base16_palette`]: https://github.com/LGUG2Z/komorebi/tree/f08aa55511d77ca56ab0e789efabeb0a237a463e/komorebi-themes
[`WindowManager::focus_follows_mouse`]: ../../komorebi/src/window_manager.rs
[`Backend::set_focus_follows_mouse`]: ../../komorebi/src/backend/mod.rs
[`Kwinrc::restore_keys`]: ../../komorebi/src/kwin/kwinrc.rs
[`transparency_manager`]: ../../komorebi/src/transparency_manager.rs
[`transparency_manager::apply`]: ../../komorebi/src/transparency_manager.rs
[`transparency_manager::transparent_windows`]: ../../komorebi/src/transparency_manager.rs
[`transparency_manager::restore`]: ../../komorebi/src/transparency_manager.rs
[`Backend::set_opacity`]: ../../komorebi/src/backend/mod.rs
[`WindowManager::opacity_applied`]: ../../komorebi/src/window_manager.rs
[`animation::movement_animation`]: ../../komorebi/src/animation/mod.rs
[`animation::movement_style`]: ../../komorebi/src/animation/mod.rs
[`AnimationStyle::qt_curve`]: ../../komorebi/src/core/animation.rs
[`AnimationPrefix`]: ../../komorebi/src/animation/prefix.rs
[`Backend::set_border_colours`]: ../../komorebi/src/backend/mod.rs
[`border_manager::window_kinds`]: ../../komorebi/src/border_manager/mod.rs
[`border_manager::update_colours`]: ../../komorebi/src/border_manager/mod.rs
[`WindowManager::retile_all`]: ../../komorebi/src/window_manager.rs
[`Ring`]: ../../komorebi/src/ring.rs
[`Monitor`]: ../../komorebi/src/monitor.rs
[`Workspace`]: ../../komorebi/src/workspace.rs
[`Workspace::update`]: ../../komorebi/src/workspace.rs
[`WorkspaceGlobals`]: ../../komorebi/src/workspace.rs
[`Container`]: ../../komorebi/src/container.rs
[`Window`]: ../../komorebi/src/window.rs
[`Window::should_manage`]: ../../komorebi/src/window.rs
[`should_act`]: ../../komorebi/src/window.rs
[`RuleDebug`]: ../../komorebi/src/window.rs
[`GlobalState`]: ../../komorebi/src/state.rs
[`MatchingRule`]: ../../komorebi/src/core/config_generation.rs
[`ApplicationIdentifier`]: ../../komorebi/src/core/mod.rs
[`Window::set_position`]: ../../komorebi/src/window.rs
[`Window::hide`]: ../../komorebi/src/window.rs
[`Window::restore`]: ../../komorebi/src/window.rs
[`HIDDEN_WINDOWS`]: ../../komorebi/src/lib.rs
[`Container::add_window`]: ../../komorebi/src/container.rs
[`Container::hide`]: ../../komorebi/src/container.rs
[`Container::load_focused_window`]: ../../komorebi/src/container.rs
[`Container::restore`]: ../../komorebi/src/container.rs
[`Workspace::move_window_to_container`]: ../../komorebi/src/workspace.rs
[`Workspace::new_container_for_focused_window`]: ../../komorebi/src/workspace.rs
[`Workspace::remove_window`]: ../../komorebi/src/workspace.rs
[`Workspace::focus_container_by_window`]: ../../komorebi/src/workspace.rs
[`Workspace::restore`]: ../../komorebi/src/workspace.rs
[`Workspace::hide`]: ../../komorebi/src/workspace.rs
[`Workspace::window_container_behaviour`]: ../../komorebi/src/workspace.rs
[`Workspace::float_override`]: ../../komorebi/src/workspace.rs
[`WindowManager::add_window_to_container`]: ../../komorebi/src/window_manager.rs
[`WindowManager::remove_window_from_container`]: ../../komorebi/src/window_manager.rs
[`WindowManager::stack_all`]: ../../komorebi/src/window_manager.rs
[`WindowManager::unstack_all`]: ../../komorebi/src/window_manager.rs
[`WindowManager::restore_all_windows`]: ../../komorebi/src/window_manager.rs
[`WindowManager::cycle_container_window_in_direction`]: ../../komorebi/src/window_manager.rs
[`WindowManager::cycle_container_window_index_in_direction`]: ../../komorebi/src/window_manager.rs
[`WindowManager::focus_container_window`]: ../../komorebi/src/window_manager.rs
[`WindowManager::window_management_behaviour`]: ../../komorebi/src/window_manager.rs
[`Backend::hide`]: ../../komorebi/src/backend/mod.rs
[`Table::hide_commands`]: ../../komorebi/src/kwin/state.rs
[`Table::restore_commands`]: ../../komorebi/src/kwin/state.rs
[`Table::window_workspace`]: ../../komorebi/src/kwin/state.rs
[`Table::stale_park`]: ../../komorebi/src/kwin/state.rs
[`NeedsPark`]: ../../komorebi/src/kwin/state.rs
[`Workspace::new_container_for_window`]: ../../komorebi/src/workspace.rs
[`WindowManager`]: ../../komorebi/src/window_manager.rs
[`WindowManager::process_event`]: ../../komorebi/src/process_event.rs
[`WindowManager::update_focused_workspace`]: ../../komorebi/src/window_manager.rs
[`WindowManager::focus_container_in_direction`]: ../../komorebi/src/window_manager.rs
[`WindowManager::focus_container_in_cycle_direction`]: ../../komorebi/src/window_manager.rs
[`WindowManager::mouse_follows_focus`]: ../../komorebi/src/window_manager.rs
[`WindowManager::move_container_in_direction`]: ../../komorebi/src/window_manager.rs
[`WindowManager::move_container_in_cycle_direction`]: ../../komorebi/src/window_manager.rs
[`Workspace::swap_containers`]: ../../komorebi/src/workspace.rs
[`Workspace::layout_flip`]: ../../komorebi/src/workspace.rs
[`Workspace::layout_options`]: ../../komorebi/src/workspace.rs
[`Workspace::resize_dimensions`]: ../../komorebi/src/workspace.rs
[`WindowManager::resize_window`]: ../../komorebi/src/window_manager.rs
[`WindowManager::toggle_float`]: ../../komorebi/src/window_manager.rs
[`WindowManager::toggle_lock`]: ../../komorebi/src/window_manager.rs
[`WindowManager::toggle_monocle`]: ../../komorebi/src/window_manager.rs
[`WorkspaceLayer`]: ../../komorebi/src/workspace.rs
[`Workspace::layer`]: ../../komorebi/src/workspace.rs
[`Workspace::floating_layer_behaviour`]: ../../komorebi/src/workspace.rs
[`WindowManager::focus_floating_window_in_direction`]: ../../komorebi/src/window_manager.rs
[`WindowManager::focus_floating_window_in_cycle_direction`]: ../../komorebi/src/window_manager.rs
[`WindowManager::move_floating_window_in_direction`]: ../../komorebi/src/window_manager.rs
[`WindowManager::toggle_maximize`]: ../../komorebi/src/window_manager.rs
[`WindowManager::monocle_on`]: ../../komorebi/src/window_manager.rs
[`WindowManager::monocle_off`]: ../../komorebi/src/window_manager.rs
[`WindowManager::cycle_monocle`]: ../../komorebi/src/window_manager.rs
[`WindowManager::monocle_focus_behaviour`]: ../../komorebi/src/window_manager.rs
[`Workspace::monocle_container`]: ../../komorebi/src/workspace.rs
[`Workspace::new_monocle_container`]: ../../komorebi/src/workspace.rs
[`Workspace::reintegrate_monocle_container`]: ../../komorebi/src/workspace.rs
[`Workspace::maximized_window`]: ../../komorebi/src/workspace.rs
[`Workspace::new_maximized_window`]: ../../komorebi/src/workspace.rs
[`Workspace::reintegrate_maximized_window`]: ../../komorebi/src/workspace.rs
[`WindowManager::adjust_workspace_padding`]: ../../komorebi/src/window_manager.rs
[`Workspace::apply_window_based_work_area_offset`]: ../../komorebi/src/workspace.rs
[`Monitor::update_workspace_globals`]: ../../komorebi/src/monitor.rs
[`WindowManager::manage_focused_window`]: ../../komorebi/src/window_manager.rs
[`WindowManager::unmanage_focused_window`]: ../../komorebi/src/window_manager.rs
[`WindowManager::is_paused`]: ../../komorebi/src/window_manager.rs
[`WindowManager::unmanaged_window_operation_behaviour`]: ../../komorebi/src/window_manager.rs
[`WindowManager::handle_unmanaged_window_behaviour`]: ../../komorebi/src/window_manager.rs
[`WindowManagementBehaviour::toggle_float_placement`]: ../../komorebi/src/core/mod.rs
[`WindowManager::promote_container_to_front`]: ../../komorebi/src/window_manager.rs
[`WindowManager::promote_container_swap`]: ../../komorebi/src/window_manager.rs
[`WindowManager::promote_focus_to_front`]: ../../komorebi/src/window_manager.rs
[`Workspace::promotion_swap_container_idx`]: ../../komorebi/src/workspace.rs
[`WindowManager::resize_delta`]: ../../komorebi/src/window_manager.rs
[`Workspace::latest_layout`]: ../../komorebi/src/workspace.rs
[`Workspace::container_idx_from_current_point`]: ../../komorebi/src/workspace.rs
[`Workspace::contains_managed_window`]: ../../komorebi/src/workspace.rs
[`WindowManager::pending_move_op`]: ../../komorebi/src/window_manager.rs
[`WindowManager::transfer_window`]: ../../komorebi/src/window_manager.rs
[`WindowManager::pending_resize_op`]: ../../komorebi/src/window_manager.rs
[`Workspace::container_idx_for_window`]: ../../komorebi/src/workspace.rs
[`Table::drag_origin`]: ../../komorebi/src/kwin/state.rs
[`Table::drag_end`]: ../../komorebi/src/kwin/state.rs
[`Backend::drag_end`]: ../../komorebi/src/backend/mod.rs
[`LiveResize`]: ../../komorebi/src/window_manager.rs
[`WindowManager::live_resize`]: ../../komorebi/src/window_manager.rs
[`live_resize_begins`]: ../../komorebi/src/window.rs
[`send_notification`]: ../../komorebi/src/window_manager_event_listener.rs
[`LayoutOptions`]: ../../komorebi/src/core/mod.rs
[`Workspace::tile`]: ../../komorebi/src/workspace.rs
[`Layout`]: ../../komorebi/src/core/mod.rs
[`Container::preselect`]: ../../komorebi/src/container.rs
[`WindowManager::change_workspace_layout_default`]: ../../komorebi/src/window_manager.rs
[`WindowManager::cycle_layout`]: ../../komorebi/src/window_manager.rs
[`WindowManager::flip_layout`]: ../../komorebi/src/window_manager.rs
[`WindowManager::preselect_container_in_direction`]: ../../komorebi/src/window_manager.rs
[`Workspace::new_idx_for_direction`]: ../../komorebi/src/workspace.rs
[`Workspace::new_idx_for_cycle_direction`]: ../../komorebi/src/workspace.rs
[`OperationDirection`]: ../../komorebi/src/core/mod.rs
[`CycleDirection`]: ../../komorebi/src/core/mod.rs
[`WindowManagerEvent`]: ../../komorebi/src/window_manager_event.rs
[`window_manager_event_listener`]: ../../komorebi/src/window_manager_event_listener.rs
[`listen_for_events`]: ../../komorebi/src/process_event.rs
[`KWinBackend`]: ../../komorebi/src/kwin/mod.rs
[`connect`]: ../../komorebi/src/kwin/mod.rs
[`kwin`]: ../../komorebi/src/kwin/mod.rs
[`kwin::state`]: ../../komorebi/src/kwin/state.rs
[`Table`]: ../../komorebi/src/kwin/state.rs
[`Table::handle`]: ../../komorebi/src/kwin/state.rs
[`Table::compositor_lost`]: ../../komorebi/src/kwin/state.rs
[`Table::switch_commands`]: ../../komorebi/src/kwin/state.rs
[`Table::window_workspace_commands`]: ../../komorebi/src/kwin/state.rs
[`Kwinrc`]: ../../komorebi/src/kwin/kwinrc.rs
[`Backend::switch_workspace`]: ../../komorebi/src/backend/mod.rs
[`Monitor::load_focused_workspace`]: ../../komorebi/src/monitor.rs
[`WindowManager::sync_workspace_desktops`]: ../../komorebi/src/window_manager.rs
[`WindowManager::adopt_workspace_change`]: ../../komorebi/src/window_manager.rs
[`WindowManager::apply_wallpaper_for_monitor_workspace`]: ../../komorebi/src/window_manager.rs
[`WindowManager::focus_workspace`]: ../../komorebi/src/window_manager.rs
[`WindowManager::move_container_to_workspace`]: ../../komorebi/src/window_manager.rs
[`WindowManager::monitor_workspace_index_by_name`]: ../../komorebi/src/window_manager.rs
[`WindowManager::focus_monitor`]: ../../komorebi/src/window_manager.rs
[`WindowManager::monitor_idx_in_direction`]: ../../komorebi/src/window_manager.rs
[`WindowManager::monitor_idx_from_window`]: ../../komorebi/src/window_manager.rs
[`WindowManager::move_container_to_monitor`]: ../../komorebi/src/window_manager.rs
[`WindowManager::cross_monitor_move_behaviour`]: ../../komorebi/src/window_manager.rs
[`WindowManager::cross_boundary_behaviour`]: ../../komorebi/src/window_manager.rs
[`Monitor::focus_workspace`]: ../../komorebi/src/monitor.rs
[`Monitor::move_container_to_workspace`]: ../../komorebi/src/monitor.rs
[`monitor_reconciliator`]: ../../komorebi/src/monitor_reconciliator.rs
[`MonitorNotification`]: ../../komorebi/src/monitor_reconciliator.rs
[`MonitorNotification::Resize`]: ../../komorebi/src/monitor_reconciliator.rs
[`listen_for_notifications`]: ../../komorebi/src/monitor_reconciliator.rs
[`update_monitor_work_areas`]: ../../komorebi/src/desktop.rs
[`load_monitor_information`]: ../../komorebi/src/desktop.rs
[`MonitorNotification::DisplayConnectionChange`]: ../../komorebi/src/monitor_reconciliator.rs
[`reconcile_display_change`]: ../../komorebi/src/monitor_reconciliator.rs
[`insert_in_monitor_cache`]: ../../komorebi/src/monitor_reconciliator.rs
[`WindowManager::evacuate_monitor`]: ../../komorebi/src/reconcile.rs
[`NotificationEvent::Monitor`]: ../../komorebi/src/lib.rs
[`bridge.js`]: ../../komorebi/src/kwin/bridge.js
[`kwin-api.d.ts`]: ../../komorebi/src/kwin/kwin-api.d.ts
[`bridge.test.js`]: ../../komorebi/src/kwin/bridge.test.js
[`fixtures`]: ../../komorebi/src/kwin/fixtures
[`DATA_DIR`]: ../../komorebi/src/lib.rs
[`LOG_DIR`]: ../../komorebi/src/lib.rs
[`SocketMessage`]: ../../komorebi/src/core/mod.rs
[`StateQuery`]: ../../komorebi/src/core/mod.rs
[`State`]: ../../komorebi/src/state.rs
[`State::has_been_modified`]: ../../komorebi/src/state.rs
[`SubscribeOptions`]: ../../komorebi/src/core/mod.rs
[`Notification`]: ../../komorebi/src/lib.rs
[`NotificationEvent`]: ../../komorebi/src/lib.rs
[`notify_subscribers`]: ../../komorebi/src/lib.rs
[`SUBSCRIPTION_SOCKETS`]: ../../komorebi/src/lib.rs
[`SUBSCRIPTION_SOCKET_OPTIONS`]: ../../komorebi/src/lib.rs
[`WindowManager::new`]: ../../komorebi/src/window_manager.rs
[`WindowManager::stop`]: ../../komorebi/src/window_manager.rs
[`WindowManager::process_command`]: ../../komorebi/src/process_command.rs
[`listen_for_commands`]: ../../komorebi/src/process_command.rs
[`read_commands_uds`]: ../../komorebi/src/process_command.rs
[`send_query`]: ../../komorebi-client/src/lib.rs
[`send_message`]: ../../komorebi-client/src/lib.rs
[`send_batch`]: ../../komorebi-client/src/lib.rs
[`subscribe`]: ../../komorebi-client/src/lib.rs
[`subscribe_with_options`]: ../../komorebi-client/src/lib.rs