Feature/ibiticu/plugin new cpu bars

[ioandev]

Plugin

• Id: ioandev/cpu-bars
• New plugin
• Update to an existing plugin (version bumped in plugin.toml)

What it does

Depends on noctalia-dev/noctalia#3515, which adds the noctalia.systemStats() and noctalia.nowMs() bindings this plugin needs and raises the plugin API to 5. This cannot merge before that ships — until then plugin_api = 5 is too new and the plugin will not load. Happy to keep this as a Draft until #3515 lands.

Draws one thin vertical bar per logical CPU core in the bar, each filling from the bottom in proportion to that core's usage over the last second. A core at or above the warning threshold (90% by default) switches to the warning colour.

The point is what an averaged CPU percentage hides. A single pegged thread and mild uniform load across every core produce the same "8%" readout, but they mean very different things — one is a runaway process, the other is a machine working normally. Per-core bars make that visible at a glance, in roughly the width of a normal bar widget.

Idle cores show an empty track rather than a sliver, so a busy core stands out instead of blending into a solid line. Colours are theme role tokens, so they follow the active colour scheme, including light/dark switches. On a vertical bar the widget rotates: cores stack downward and each bar fills from the left.

Eight settings: bar width, gap, length, warning threshold, bar/warning/track colours, and an icon toggle.

External dependencies

None. No network calls, no spawned processes, no filesystem writes. Per-core usage comes from the host via noctalia.systemStats(), which reads /proc/stat, so the plugin is Linux-only.

Testing

Added the widget to a bar and exercised it end-to-end against a local build of noctalia#3515.

Correctness of the per-core mapping was checked against ground truth rather than eyeballed: load was pinned to known cores with taskset and the matching bars confirmed, so bar N really is core N-1. Cores 3 and 17 pinned lit exactly bars 4 and 18; repeated with cores 0-3 + 12-13, and with 6/7/15. Partial load via stress-ng --cpu-load at 100% / 75% / 55% / 25% produced proportional bar heights, and the warning colour appeared only on bars at or above the threshold, clearing when the load stopped.

All eight settings were changed and confirmed to take effect: bar width, gap and length visibly resize the widget, and lowering the warning threshold to 50 turned the mid-load bars red. The tooltip was checked for the total plus the per-core breakdown. The wallpaper was changed mid-run — the palette here is wallpaper-derived — and the bars followed the new scheme, confirming the role tokens resolve live rather than being sampled once.

Tick alignment was measured by logging noctalia.nowMs() % 1000 each update: it converges within a couple of ticks and holds at 4-16 ms past the second, one update per second with no skipped or doubled seconds.

Not exercised: the vertical-bar orientation. The code path exists — barWidget.isVertical() swaps the container and fills each bar from the left — but the test bar was horizontal throughout, so I cannot claim it works. Also untested: machines with a very low or very high core count (this is a 24-core box), and CPU hotplug.

• Tested on Niri
• Tested on Hyprland
• Tested on Sway
• Tested on another compositor:
• Noctalia version tested against: local build of feat(plugins): add noctalia.systemStats and per-core CPU sampling noctalia#3515, v5.0.0-beta.3-35-ge83f7ab59b42
• Plugin API level: 5

Screenshots / Videos

To attach: the widget under mixed load — some cores pegged and red, some at partial height, the rest idle — plus an idle shot showing empty tracks.

Checklist

• The directory name matches the part of id after the / in plugin.toml exactly.
• It ships plugin.toml, README.md, thumbnail.webp, and translations/en.json.
• README.md follows the README template, documents every entry id and dependency, and includes exact panel IPC commands and launcher prefixes where applicable.
• [xI created thumbnail.webp with the thumbnail generator.
• version follows semver and is bumped in this PR; plugin_api is the oldest API level this plugin requires.
• Every non-English translation in this PR uses a locale supported by Noctalia core, and I can read, write, and understand that language well enough to review and maintain it (no unreviewed machine/LLM translations).
• I did not edit catalog.toml; CI generates it.
• This PR touches exactly one plugin directory.

This PR adds only translations/en.json. No other locales are included, so there is nothing machine-translated to review.

Code review attestation

• The code is readable and not obfuscated, minified, or generated.
• It does not download and execute remote code.
• Every network call, filesystem write, and spawned process is something the description above accounts for.
• I have the right to publish this code under the license declared in plugin.toml.

The plugin is a single 148-line Luau file with no dependencies and no I/O of any kind: it reads noctalia.systemStats() and noctalia.getConfig(), builds a ui.row of boxes, and sets a tooltip. The only non-obvious part is scheduleNextTick(), which corrects its own update interval to land on the second boundary; it is commented in place, since the reason is not guessable from the code.

[ioandev]

There is a problem with this plugin. Every time a change in the bar takes place, the plugin gets reloaded and it waits a second between it redraws. I will fix.

• Fixed