# UI scale

Every classroom gets the same design at a size that suits its TV. A 32"
panel a few feet from the children and a 65" set across a hall want
different sizes of the same dock, not different docks.

## Changing it

Edit `/etc/ekklesia-classroom/device.conf` on that endpoint:

```
UI_SCALE=1.25
```

Then restart the classroom shell:

```
sudo systemctl restart getty@tty1
```

That ends the session and the autologin brings it straight back with the
new size. A reboot does the same thing. Nothing else needs touching, and
no CSS or source file is ever edited to change a room's size.

## Values

| UI_SCALE | Roughly |
| --- | --- |
| 0.8 | Small or close-up panel |
| 1.0 | Default. 1080p classroom TV, 32–50" |
| 1.25 | Large room, or a set viewed from further back |
| 1.5 | 65"+ |

Anything outside 0.8–1.5 is clamped to that range, and anything that is
not a number at all falls back to 1.0, so a typo in device.conf cannot
produce an unusable shell.

## What it scales

- Dock height, and the reserved strip at the bottom of the screen
- Dock corner radius, padding and the spacing between buttons
- Button size, padding and corner radius
- Every dock icon
- Clock text size, padding, corner radius and its inset from the edge
- Notification width, height, padding, margin, corner radius, text size
  and icon size

Colours, translucency and the hairline borders do not scale: those are
the design, not the size. At `UI_SCALE=1.0` the rendered stylesheet is
byte-identical to the one the shell used before scaling existed.

## How it works

`/etc/ekklesia-classroom/dock/style.css.in` and
`/etc/ekklesia-classroom/mako/config.in` are templates carrying
measurement tokens. `classroom-dock` resolves the stylesheet in memory at
startup; `classroom-notifications` resolves the notification config into
the session's runtime directory and hands it to mako. Neither template is
ever rewritten on disk, so an update cannot lose a room's setting and a
room's setting cannot drift from the packaged design.