# Phosphor Scope

A cathode-ray tube behind smoked glass. The beam leaves light behind it: a radar sweep lights your contacts and they fade, a trace glows where the signal lingers. Real afterglow, not a blur.

Object · With a Pass · https://tactileui.dev/objects/phosphor-scope

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## Anatomy

Phosphor persistence buffer, Two decay phosphor, Gaussian beam segments, Dwell weighted energy, Radar sweep fan, Ground clutter speckle, Vector stroke font, Mip chain halo, Barrel curve, Room fixed glass, Sleeping loop, Long exposure still

## Usage notes

A live display for software that watches something. A radar of services, regions or agents in the field (each contact painted and labelled as the sweep passes); an oscilloscope for a health check's pulse, a service's load, or any stream you push to it; a Lissajous figure for a hero or a loading screen; a status or a 404 written by the beam: SIGNAL LOST, NO CARRIER, DEPLOYING.

## Options

| Option | Type | Description |
| - | - | - |
| mode | enum | A radar that lights its contacts, a scope trace, a Lissajous figure, or words drawn by the beam. |
| phosphor | enum | P1 green, P3 amber, or P7: a blue-white flash that leaves a yellow-green glow. |
| persistence | number | How long the light stays after the beam has gone. |
| intensity | number | Intensity |
| focus | number | Soft to sharp: the width of the beam. |
| sweep | number | Radar only. |
| contacts | number | Radar only: sample services, each labelled by the beam as it is painted. |
| signal | enum | Scope only: a health-check pulse, a service load, or a test waveform. In code, push() draws your own. |
| timebase | number | Scope only. |
| ratio | enum | Lissajous only. |
| text | text | Text only. A new line with /. |
| on | boolean | Power |
| finish | enum | Auto draws the plate and ring in the page’s finish (its surface and object tokens); without them, graphite on a dark page and aluminium on a light one. The tube stays black glass. |

## Methods

- update
- setTargets
- push
- setText
- power
- destroy

## States

1. **Radar**: The sweep turns at the set rate; its painting edge flashes and leaves the slow afterglow behind it over ground clutter; each contact flares when the sweep crosses its bearing, its label written beside it by the beam, and fades until the next pass.
2. **Scope**: The trace runs across the graticule over the timebase; it glows brighter where the signal is slow and fainter where it races; the retrace is dark. With signal 'stream', push() draws your samples as they arrive.
3. **Lissajous**: A figure of the set ratio, its phase drifting so it slowly turns; the moving spot is the brightest point.
4. **Text**: The words are redrawn by the beam every frame with a hair of jitter; a new line with a newline.
5. **Phosphors**: P1 green; P3 amber; P7 flashes blue-white and leaves a yellow-green glow that lasts seconds. Persistence scales every decay.
6. **Aluminium**: A bead-blasted aluminium plate with a machined ring and four slotted screws; the glass stays smoked.
7. **Graphite**: A soft-touch black plate, the ring and screws in dark steel; the tube is the same.
8. **Off**: power(false): the screen goes dark, the plate's lamp goes out, no frame is requested.
9. **Off screen or hidden**: No frame runs; a returning tab advances one clamped step, so nothing flashes.
10. **Reduced motion**: One still frame, a long exposure of the scene (a full radar turn, a timebase of trace), and no frames after it.
11. **No WebGL2**: The same scene drawn once on a 2D canvas with a soft glow.

## How it works

Original. The plate, ring, graticule and glass are CSS and SVG, lit by the room's lamp, never by the beam.