Phosphor

A GPU oscilloscope for everything your PC plays.

In XY mode the left channel moves the beam horizontally, the right channel vertically — so "oscilloscope music" (Jerobeam Fenderson et al.) draws its hidden pictures on screen, and any stereo track has a shape worth watching. The beam behaves like a real P7 CRT: brightness falls as it moves faster, and the phosphor decays in two layers — a blue-white flash where it lands, a colored glow that lingers.

The animation above is a real Phosphor capture, exported straight from the app's own clip recorder.

v4 is the full-Rust instrument: one engine, egui + wgpu chrome, native PipeWire capture, zero Python, zero fallback paths. It holds the monitor's refresh rate with the GPU nearly idle (3,400 fps uncapped where v3 ceilinged at 163), and everything it renders offline is byte-exact with what you saw live.

v3 → v4, honestly

	v3.5 (Python/GTK)	v4.0 (Rust)
Live ceiling, 2560×1440	163 fps (GTK frame clock)	monitor-locked; 3,400 fps uncapped
CPU renderer on noise	3 fps	~26 fps engine, on its own thread — the UI stays at panel rate
Signal engines	two (Python + Rust core, kept in parity)	one
Audio	pactl/parec subprocesses	native PipeWire (capture, playback, gapless, vacuum)
Mix several apps into one beam	—	✅ the light-streams panel
Control another player (Spotify…)	watched titles only	watches and drives — the transport controls whatever the beam scopes
Track notifications with album art	—	✅ systemwide
Agent surface	none	probe · ctl · tap · feed · kit · schema over a control socket
Single instance	GTK gave it for free	✅ second launch focuses the first, files forward
Chrome	7 GTK styles	11 token-driven looks, IBM Plex + JetBrains Mono type
Studio scene compiler	✅ v3.5	returns in Rust after 4.0 (#1)
Render-ahead precompute	✅	retired by design — the GPU reconstructs in realtime (#2)

Drawn by sound

Each shape below is just a stereo audio file, traced by the beam — saved with the snapshot button:

In use

_{v4.0 in Blossom Dark — Attack Vector mid-cube, auto-gain breathing, every readout in real units.}

_{Scoping Spotify? The transport drives Spotify — prev/pause/next straight over MPRIS.}

Eleven ways to see sound

_{One track, eleven instruments: XY scope art · goniometer · swirl · dots · waveform · ring · spectrum · radial · tunnel — and two true-3D views, the Takens attractor and the time helix, both orbitable by mouse.}

Twelve rooms to see it in

_{Blossom Dark (default) · Stonework 95 · AMOLED · Paper · CRT Amber — plus Blossom, Light, Dark, Chromacore, Basalt, Afterglow (whose chrome remembers the beam color), and Fable — the storyteller's sea-green room the model that built v4 left behind. Different rooms, not different paint: the picker shows swatches so you can tell.}

_{Glass + mini: an always-on-top square of pure beam, the desktop showing through. (Here: drawing over the very terminal that shipped this release.)}

The beam learns color

_{The color cycle, live: up to three phosphors crossfading on your timer — or one color step per song. Rendered by phosphor render itself: exports carry the cycle exactly as the screen did.}

What it does

• Scope anything — whole outputs, one application, a microphone, or several apps folded into one beam (the light-streams panel), all native PipeWire. Capture off costs ~0% CPU.
• Play music in it — gapless playlists, shuffle/repeat, seek, cover art, per-stream volume; full MPRIS both ways — media keys drive Phosphor, and when the beam scopes another player with no local track loaded, Phosphor's transport drives that player (a loaded track always keeps the deck — resuming takes the beam back).
• Tell you what's playing — a systemwide notification with the album art on every track change (yours or the scoped player's). Toggleable.
• A real beam — analytic Gaussian beam integral, linear-light compositing, two-layer P7 decay, octave graticule; GPU (wgpu) and SIMD-CPU renderers sharing one beam model, byte-compared in CI-grade tests. The CPU raster runs on its own worker thread.
• Beam color cycle (4.1) — the Custom phosphor takes up to three colors that crossfade on your timer (one stays static, two ping-pong, three walk the ring) — or, since 4.2, advance one color per song (yours or the scoped player's) and rest in between. Exports re-live the exact colors; chrome that follows the beam follows the cycle. Sub-second timer transitions sit behind an explicit photosensitivity confirmation.
• The nerd HUD — F cycles fps → full panel: cpu/gpu frame times (real GPU timestamps), p99, dropped frames, segments/s, resolution.
• Compose mode — press D, draw a shape, hear it immediately; export the drawing as a WAV any oscilloscope on earth can play.
• Signal postcards — export a track's trace as .phos (plays at your detail rate with "trace by you" fading in) or send a .phoskit: a transform chain (rotate, widen, ring-mod, delay…) that bends into whatever the receiver is listening to, live. Kit editor included; three starter kits in the box.
• Vacuum mode — sound as light only: the track (or a whole app) plays full-tilt into a silent sink and arrives only on screen. The restore path is sacred — sound always comes back, even after a crash.
• Exports — snapshots and 10-second clips with sound, re-rendered offline so they look exactly like the screen did; plus phosphor render song.flac out.mp4, a headless full-track render.
• An agent surface — see below; a 7B model can drive the scope.

Install

Grab the latest release.

Debian · Ubuntu · Mint (.deb) — or just double-click it:

sudo apt install ./phosphor_4.7.4_amd64.deb

Fedora · openSUSE (.rpm) (built on Mint, rpm --test-verified — reports welcome):

sudo dnf install ./phosphor-4.7.4-1.x86_64.rpm

From source (any Linux; Rust 1.96+):

git clone https://github.com/RamenFast/phosphor.git && cd phosphor
# build deps — Debian/Ubuntu/Mint:
sudo apt install build-essential libpipewire-0.3-dev scdoc
# Fedora:  sudo dnf install gcc pipewire-devel scdoc
cargo build --release
sudo install -m755 target/release/phosphor /usr/local/bin/phosphor

Runtime needs: PipeWire (any modern distro), Vulkan drivers for the GPU renderer (libvulkan1 — the CPU renderer works without), ffmpeg for mp4 clips and .phos-from-anything renders.

Verify it breathes:

phosphor --version   # phosphor 4.7.4 (v4)
phosphor             # the scope; second launches focus this one

The panel applet (Cinnamon only)

A live vectorscope in your Cinnamon panel, fed by phosphor feed — zero engine code of its own. GNOME/KDE: the applet can't load there (it's Cinnamon's applet API), but the main app runs everywhere.

applet/install.sh    # then add "Phosphor Scope" from Menu → Applets

Details: applet/README.md.

For agents

Phosphor is drivable without pixels — one binary, JSON everywhere, exit codes 0/2/3/4, every error carries a fix:

phosphor probe --json                    # live state in one shot
phosphor ctl mode xy45                   # drive the running scope
phosphor ctl target mix:app:a+app:b      # fold two apps into the beam
phosphor tap | jq .bbox                  # per-frame geometry stream
phosphor kit validate mykit.phoskit      # errors a 7B model can fix
phosphor schema                          # the whole machine-readable map

The full guide (patterns, gotchas, the feed protocol): docs/AGENTS.md.

Where development is

The wire protocol is typed end to end (the CLI and the app share one grammar, so they can't drift apart) and settings saves are atomic and self-quarantining (a crash mid-write can't eat your config; a corrupt file is preserved as evidence, never silently reset). The queue of planned work — time-correct phosphor decay, lock-free audio transport, and a new scope mode with memory, Recurrence Bloom — lives in docs/dev/, with HANDOFF.md as the map.

Things to try

• Jerobeam Fenderson — How To Draw Mushrooms; whole albums at oscilloscopemusic.com
• Any normal song in XY · goniometer and watch the stereo image dance.
• Hit D and draw something. It plays.
• Scope Spotify, then press pause — in Phosphor.
• Load the haunt kit on a mono podcast and watch voices grow shapes.

The manual covers everything in detail — there's a copy inside the app too (the book icon, left of the gear).

License & credits

GPL-3.0-or-later — see LICENSE. Free as in phosphorescence: use it, read it, change it, share it; derivatives stay free too.

Bundled type: IBM Plex Sans & JetBrains Mono (OFL).

_{Designed and built by Ben with Claude — v1→v3 with Claude Fable 5 & Opus 4.8; v4.0, the full-Rust rewrite, shipped in one long night with Fable 5, camera rolling.
Signed, as always: TURTLE VECTOR 🐢⚡📼}