Displays and night light
Hub → Displays holds two things that answer the same question — what the screen physically looks like. The first two tabs are the monitor layout, one for your session and one for the login screen; the third is the night light.
The monitor layout
The Session tab lists every connected output with the controls you would expect:
- Resolution and Refresh rate — the modes the monitor actually reports.
- Scale — how large everything is drawn. Auto picks a sensible value for
the panel's size and density. The list holds only scales the compositor
accepts for this resolution, in roughly quarter steps — a panel that cannot
divide by 1.5 offers 1.6 instead. Hyprland rejects anything else and quietly
substitutes its own pick, so W never offers it;
w-monitor scales <output>prints the full set. - Rotation — for a monitor standing on its side.
- Position — where this output sits relative to the ones already placed: Left, Right, Above, Below. There is no pixel arithmetic to do; W chains the outputs for you.
- Primary — a W concept rather than a Wayland one. The primary output is the one that carries the status bar, and the one the login card and the lock screen are drawn on.
- Enabled — turn an output off without unplugging it.
Your layout lives in a settings file, not in the compositor's memory, so it
survives a reboot and a re-plug. From a terminal the same layout is w-monitor
— w-monitor status prints what you have, and w-monitor help lists the rest.
No administrator rights are involved: the session is yours.
Changing Scale or Primary also moves the lock screen, which reads its size at the moment it locks — so the change lands the next time the screen locks, not immediately.
The login screen has its own layout
The greeter is a separate program that runs before you log in, so it does not see your session's settings. The Login screen tab configures it separately, and because that file belongs to the machine rather than to you, saving it asks for your password.
That tab behaves a little differently from the first one on purpose:
- Copy from session takes the layout you just built for yourself as a starting point.
- Changes are staged and only land when you press Apply — you are editing a screen you are not currently looking at, so nothing happens behind your back. Discard throws the staged edits away.
- The hint "Changes apply on the next login screen" is literal: to see the result, log out.
Night light
The Night light tab warms the screen in the evening to cut blue light. It shifts the compositor's colour transform rather than painting over the screen, which has two pleasant consequences: it costs nothing while you work, and it does not show up in screenshots or screen recordings.
- Mode — off, schedule (warm only inside the night window), or always.
- Temperature — the night value in kelvin; lower is warmer. 4300 is the default, 3000 is clearly amber, 2000 is candlelight.
- Day temperature — what the screen returns to when the window closes. The default 6600 leaves the screen alone; any other value is a real tint that stays on all day, which is exactly what someone who wants a permanently warmer screen is after. It is not an off switch — off means an untouched screen whatever this says.
- The night window — a start and an end time. Crossing midnight (21:00 → 07:00) is normal. W uses clock times rather than sunset and sunrise: it ships no geolocation.
- Transition — how long the scheduled change takes, in minutes. It paces only the scheduled change; a switch you flip yourself eases across in about two seconds, so you never wait.
Super+Shift+N toggles the filter between off and schedule.
Two things surprise people, and neither is a fault. Setting the mode to schedule in the afternoon changes nothing visible until the window opens. And the login screen stays neutral — the night light lives in your session, and the greeter is a different program.
From a terminal the same settings are w-nightlight.
A black screen after a display change
This is a settings file, not a broken system, and it does not call for a rollback.
W already refuses the two changes that would obviously blind you: you cannot disable the primary output, and you cannot disable the last one still drawing. What it cannot prevent is a legitimate change that goes wrong later — turning off the laptop panel while an external monitor is attached is reasonable until the external monitor is unplugged.
If you end up looking at nothing, switch to a text console with Ctrl+Alt+F2, log in, and run:
w-monitor reset --all
sudo w-monitor greeter resetThe first line restores your session's layout to automatic, the second does the same for the login screen. Recovery covers this and the other "I cannot get back in" situations.