Research 026/04: the screensaver, monitor layouts and menus

2026-10-04 12:00:01 +02:00
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@@ -60,4 +60,5 @@ desktops. Measured in [01](01-what-the-workstations-run.md):

 - [01 — What the workstations run](01-what-the-workstations-run.md): evidence.
 - [02 — The questions and the options](02-the-questions-and-the-options.md)
+- [04 — Screensaver, displays and menus](04-screensaver-displays-and-menus.md): the lock and idle module, monitor layouts by the monitors' identity, rofi and dmenu behind one launcher seat
 - [03 — What the predecessor taught](03-what-the-predecessor-taught.md): its 128 modules and 3,395 commits, as patterns to keep and failures not to repeat; shared with research 027.
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+# 04 — Screensaver, displays and menus
+
+Three areas the operator named on 2026-10-04, as their own modules. Each sharpens a row of
+[01](01-what-the-workstations-run.md) and a question of [02](02-the-questions-and-the-options.md).
+
+## The screensaver: idle, lock and display power
+
+**Measured on both workstations:**
+
+- **Idle and lock** are three things wired by hand in the session's start script:
+  - the X screensaver timeout (`xset s 1800`);
+  - the display power timeouts (`xset dpms`);
+  - `xss-lock` running the colour build of `i3lock` through a wrapper, in a respawn loop.
+- **A second screensaver,** xscreensaver, is installed and deliberately not started. Earlier it
+  overrode the display power settings with its own, and locked nothing. Its configuration file is
+  still in the home.
+- **The lock screen's 20-odd colours and formats** were predecessor theme variables.
+- **The colour build is not in the official repositories** (research 026/01).
+
+**Starting position:**
+
+- **One module for the lock screen,** holding `node-lock-screen`: the locker and its wrapper as the
+  module's own files, the screensaver and display power timeouts, and `xss-lock`.
+- The timeouts and colours are its defaults, and settings later (issue 168).
+- The colour build ships as ADR 0205's pinned archive, or the module uses the official `i3lock`.
+  That is the operator's choice, and the colours are the only difference.
+- xscreensaver is not a module; its package and file are removed.
+- `xss-lock` needs the logind session, so it stays a session-start line contributed into
+  `.xinitrc`'s block (question 4), not a unit.
+
+## Monitor layout (xrandr)
+
+**Measured:**
+
+- Each workstation has a layout script generated by `arandr`, with the monitor names baked in. One
+  workstation also has several layouts for named places, a hotplug rule and a wizard.
+- **The desktop carried the laptop's layout scripts.**
+- No `xorg.conf.d`, and no layout tool beyond the scripts.
+
+**Starting position: `autorandr`** (official repositories) inside the display server's module.
+
+- `autorandr` saves a layout as a profile **keyed by the connected monitors' identities** (their EDID)
+  and applies the matching one at login and on hotplug.
+- Profiles therefore need no machine's name. A profile can be shared mesh-wide and simply never
+  matches on a machine without those monitors. That is exactly the "say it by what is there, never by
+  a name" rule (ADR 0112).
+- The profiles are the operator's data, saved by the tool itself, so they are *found* (ADR 0182). A
+  `layout` verb on `node-display-server` lists, saves and applies them.
+- The arandr scripts and the hotplug rule retire once a profile exists for each.
+
+## Menus: rofi and dmenu
+
+**Measured:**
+
+- rofi is the launcher, the power menu, the theme picker and the clipboard menu.
+- The operator's scripts call `rofi -dmenu` in four places and **plain `dmenu` in two. dmenu is
+  installed on neither workstation, so those two fail.**
+
+**Starting position:**
+
+- **`rofi` holds `node-launcher`**, and the seat's protocol includes a **dmenu-compatible command**:
+  read choices on standard input, print the chosen one. Scripts call that command, not a program by
+  name.
+- **`dmenu` is a module of its own** (official repositories), able to hold the same seat on a machine
+  that wants it, for instance a Wayland session where `wofi` or `fuzzel` would hold it instead.
+- The rofi module carries its theme files, and the menus that belong to other modules arrive as those
+  modules' scripts:
+  - power menu → the session;
+  - clipboard menu → the clipboard module;
+  - theme picker → settings, once issue 168 closes.