# Displays (/docs/haus/rooms/displays)



This room scales a screen, so the whole Mac gets bigger or smaller, apps haus
has never heard of included; `haus.ui.scale` and `haus.fonts` only resize
haus's own surfaces. An empty `haus.displays` leaves every screen as macOS has
it.

```nix
haus.displays = {
  internal.uiScale = "larger-text";   # the built-in panel
  main.uiScale = "default";           # whichever display is main
  "37D8832A-2D66-02CA-B9F7-8F30A301B230".uiScale = "more-space";   # hausdisp list prints the UUIDs
};
```

```sh
haus rebuild
```

`uiScale` is an intent, not a pixel count: `more-space`, `default`,
`slightly-larger-text`, `larger-text`, `largest-text`, each resolved against
the ladder of modes *that* screen reports. A monitor that isn't attached is
skipped with a note, not a failed rebuild. A desktop may name `internal` and
`main`; a UUID is **host-only**.

## Arrangement [#arrangement]

Where a display sits relative to another, as a relation rather than a pixel
origin:

```nix
haus.displays.internal.arrangement = {
  side = "right-of";   # right-of | left-of | above | below
  of = "main";         # which display this one sits beside
  align = "top";       # top/center/bottom for right-of and left-of,
                       # left/center/right for above and below
                       # (null pins the shared edge)
};
```

Set `side` and `of` together: an arrangement with only one of them doesn't
eval, and the error says so rather than guessing.

The origin is computed at each activation from both panels' current point
sizes, so the same relation follows a scaling change. Because origins are in
points, every `uiScale` entry applies before any `arrangement` entry; where two
displays each carry an arrangement, the one named in `of` is placed first, so a
desk can be built in relations. A cycle is refused at eval.

`main` is part of what an arrangement asserts: macOS makes a display main by
putting it at the origin (0, 0), and a relation can put one there. When it
does, that display becomes main. Check what a relation resolves to before you
commit it:

```sh
hausdisp arrange internal right-of main top --dry-run
hausdisp list   # prints the `at x,y` to compare against
```

An arrangement is about a desk, so it applies only while BOTH displays are
attached; an absent one is skipped with a note and re-asserted at the next
activation after the dock returns. Between activations macOS keeps its own
remembered arrangement.

## Remove it [#remove-it]

Delete the entry and rebuild. That stops *managing* the screen rather than
restoring it: the panel keeps its last mode, so set the position you want
explicitly.

## Options [#options]

[Every setting, with types and defaults](/docs/haus/reference/options#displays).