fonts: one font size for the desktop, with per-system overridesarchive/companion

A settings page under Appearance > Fonts holds one pixel size for the
whole desktop and an override wherever a system needs its own, saved as
~/.config/keystone/fonts.json, all in px. At scale 1 the logical DPI is
96, so a point is 4/3 px, and each system is written in its own unit:
Theme.fontSize reads the json itself, so every shell follows live;
qt5ct/qt6ct and the GTK settings files are edited in place, size only,
plus gsettings; kitty, rofi and hyprlock read generated files under
~/.config/keystone that their configs include over designed fallbacks;
the groupbar is a keystone.lua line.

rofi and hyprlock are sections of designed sizes that scale together
from their body text, the smallest entry, each keeping its ratio unless
given its own size. The design is read from the fallbacks themselves,
var(kf-..., "Family N") in the rofi files and $kf_... = N in
hyprlock.conf, so a new entry appears on the page with no list to keep.

With no fonts.json the page starts from what the files say, base 16 and
an override per system at its current size, so the first save changes
nothing; seeded to 0.01px, since 0.1 scaled rofi's 72pt glyph to 72.2.
Each stepper shows px then pt in fixed columns, the system's own unit
highlighted.

Check: node desktop/modules/fonts/test_fonts.js

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 49 insertions, 0 deletions

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+# fonts
+
+One pixel size for the desktop, in the settings window under Appearance >
+Fonts, and an override wherever a system needs its own. Saved as
+`~/.config/keystone/fonts.json`:
+
+    { "base": 16, "override": { "qt": 18.67, "rofi:kf-launcher-entry": 22 } }
+
+Everything is stored in px. At scale 1 Wayland's logical DPI is 96
+(`gtk-xft-dpi` reads 98304, 96 * 1024), so a point is 4/3 of a pixel and
+16 px is 12 pt. Each system is written in its own unit:
+
+| System | Written to | Unit | Seen |
+| --- | --- | --- | --- |
+| Quickshell | `Theme.fontSize` reads `fonts.json` itself | px | at once |
+| Qt | `qt6ct.conf`, `qt5ct.conf`, `general=` and `fixed=` size field | pt | when an app starts |
+| GTK | gtk-3.0 and gtk-4.0 `settings.ini`, `.gtkrc-2.0`, gsettings `font-name` | pt | at once for GTK 3 and 4 |
+| kitty | `~/.config/keystone/kitty-fonts.conf`, included last by `kitty.conf`; SIGUSR1 reloads | pt | at once |
+| Hyprland groupbar | `group:groupbar:font_size` line in `keystone.lua` | px | at once |
+| rofi | `~/.config/keystone/rofi-fonts.rasi`, imported by udt's `common.rasi` | pt | next open |
+| hyprlock | `~/.config/keystone/hyprlock-fonts.conf`, sourced by `hyprlock.conf` | pt | next lock |
+
+Qt and GTK files are edited in place, size only; the family stays what it
+is. unified-desktop-theme's templates no longer carry those keys, so a
+re-install does not undo the page. Hyprland's text is pixels
+(`pango_font_description_set_absolute_size`), hyprlock's points
+(`pango_font_description_set_size`).
+
+rofi and hyprlock are sections: sets of designed sizes that scale together.
+Every rofi font in the udt files is `var(kf-<file>-<selector>, "Family N")`,
+and every hyprlock label is `font_size = $kf_<label>` over an inline `$kf_...
+= N`. The designed value is the fallback, used when the generated file is
+absent, and it is also where the page reads the design from, so a new entry
+in either file shows up on the page by itself. A section's size is its body
+text, the smallest designed entry; every entry keeps its ratio to that unless
+given its own size.
+
+With no `fonts.json`, the page starts from what the files say: base 16 px,
+and an override for every system at its current size, so the first save
+changes nothing.
+
+Not handled: font families; the hard-coded `pixelSize` values in the shells
+(21 of them), which do not follow `Theme.fontSize`; and a `keystone.lua`
+save from this page and the Options page at the same moment, which can drop
+one line.
+
+## Check
+
+    node desktop/modules/fonts/test_fonts.js