SegmentDisplay

A seven-segment readout drawn the way a real one looks: the segments a reading doesn't light stay faintly visible under the glass, and zeros that only pad a reading out print dim instead of vanishing. For the one number a screen is about: a frequency, a clock, an amount, a counter.

Feel A lit panel meter: the dark segments are always there under the glass, and only the reading glows.

88.5 MHz

04:59

Err

Ghost segments

Or let the agent fetch it: get_component("segment-display") on the Echo MCP server.

Installation

npx echo-ui-cli add segment-display

First time? Run npx echo-ui-cli init once — it sets the project up, and add refuses to run before it.

At a glance

Version: 0.3.0
Weight: 2.0 KB · 2.1 KB with what it imports · 1.2 KB of CSS (minified and gzipped; React not counted)
Needs: roll (Echo, brought with it), scope (Echo, brought with it)
Reduced motion: With roll, a new reading appears at once instead of stepping through the digits in between.

Usage

tsx

import { SegmentDisplay } from "@/echo/segment-display";

<SegmentDisplay label="Frequency" value="88.5" digits={4} unit="MHz" />

Composition

SegmentDisplay

Examples

Frequency

Four digits wide, so 88.5 shows a dim leading zero.

tsx

<SegmentDisplay label="Frequency" value="88.5" digits={4} unit="MHz" size="lg" />

Clock

A colon is its own narrow cell.

tsx

<SegmentDisplay label="Time left" value="04:59" />

Counting

Each new reading rolls through the digits in between.

tsx

<SegmentDisplay label="Queue" value={String(queue)} digits={3} roll />

Inside your own screen

flush drops the well, for a readout that shares a screen with other parts.

tsx

<Card variant="screen" title="Room">
  <SegmentDisplay variant="flush" label="Temperature" value="21.5" unit="°C" />
</Card>

Reflective glass

The paper glass of a pocket calculator: printed in ink, nothing glowing.

tsx

<SegmentDisplay label="Total" value="1284.50" screen="reflective" />

Accessibility

role="group" named by label, and the reading said once, as it is, with its unit: "88.5 MHz", never the padded "088.5".
The digit face is drawing, hidden from assistive technology; so are the dark segments and the padding.
In forced colors the lit segments draw in the system text colour, padding in its grey, and the dark segments go.

Tested against WCAG 2.2 AA on every release:

axe — No axe violations, in the component's own gallery and on its page.
keyboard — Every action is reachable and operable from the keyboard alone.
focus-visible — Focus is visible on every focusable part, in normal and forced-colors mode.
forced-colors — State stays visible when the look's colours are replaced by the system's.
target-size — Every target's real hit area is at least 24×24px, at every density.
reflow — Content reflows into 320px and survives a doubled text size.

Not covered: screen-reader: not yet verified by a person. Everything above is a machine check; a person has not yet driven this component with a screen reader.

Motion & sound

Reduced motion: With roll, a new reading appears at once instead of stepping through the digits in between.

Props

SegmentDisplay props
Prop	Type	Default
`value` requiredThe reading: digits, a minus, a dot, a colon, and the letters a segment face can draw.	`string \| number`
`label` requiredWhat it reads: the accessible name, and engraved over a screen display.	`string`
`unit`Engraved after the digits: "MHz", "kg".	`string`
`digits`At least this many digit cells; a shorter reading is padded on the left, and a minus stays in front of padding zeros (-05).	`number`	`0`
`pad`What fills the padding: dim zeros, the way a counter shows them, or blanks (" ").	`"0" \| " "`	`"0"`
`ghost`Draw the segments a reading doesn't light, faintly, as a real display shows them.	`boolean`	`true`
`glow`Lit in the accent; false lights it cream, for a value that isn't live.	`boolean`	`true`
`roll`A new reading rolls to its digits, each stepping through the ones in between.	`boolean`	`false`
`size`Digit height: 24, 40 or 64px.	`"sm" \| "md" \| "lg"`	`"md"`
`variant`screen sits in its own dark well; flush is the digits alone, for a screen you already have.	`"screen" \| "flush"`	`"screen"`
`screen`emissive: a dark screen that glows. reflective: the paper-coloured glass of a pocket calculator, printed in ink.	`"emissive" \| "reflective"`	`"emissive"`

Anti-patterns

Never use a SegmentDisplay for words: a seven-segment face draws digits and a few letters; anything else is a blank cell.
Never pad with digits to make a number look bigger: padding is for a face whose width is fixed (a four-digit frequency, a six-digit counter).
Never light every display on a screen: glow the one being watched, and set the rest to glow={false}.

Changelog

v0.3.0 · 2026-10-12 · AddedThe drawn device (echo-ui-core, echo-ui-cli, every component that draws its own material). A seed's new render setting is molded (Echo as it has always been: plastic lit by one key light) or drawn: the same parts drawn in the ink, the way a spec sheet draws a key. Every part is outlined at one weight (--echo-line, --echo-line-width), hollow on the body; a raised part stands on a hard ink edge as deep as it rises and travels down it when pressed; a recess is an outline drawn inside; something floating stands on a deeper edge. There's no light, so no gloss, no soft shadow and no glow: what a molded device lights (an LED, the rail, a readout, the focus ring, a fader's knob, a radio's pip) is solid ink, and a low-emphasis action is its label underlined. In black and white (the accent the ink) "on" is solid ink and what's drawn on it inverts: a switch's thumb turns paper, a fader's knob is knocked out with a paper ring. The primary key is the paper key that stands highest, on an ink edge twice as deep as a neutral one's, the way a spec sheet draws its CTA. The accent stays the seed's own colour as a flat fill for what's on (a chosen segment, a checked box, a slider's travel, a switch that's on), so an acid highlighter is acid, not the olive a molded device holds it to; what's drawn on it is the ink, or the body when the accent is too deep for the ink. Pressing, travel, sound, what each material is for and every contrast guarantee are unchanged. npx echo-ui-cli style set render drawn turns it on; a style sets it in its seed; the published style and config schemas describe it, and DESIGN.md says how a drawn device builds. A molded device renders exactly as before: every line is 0px wide there, and each drawn value a component reads (--echo-drawn-fill, -on-fill, -ink, -rule, -glass, -hollow, -decoration) is initial, so it falls back to what the component always drew. HardwareButton's bed is the one new hand-tuned shadow: a drawn key stands on its own edge instead of being drawn in a recess.
v0.3.0 · 2026-10-12 · ChangedEvery item needs echo-ui-core 0.3.0 (all components). The drawn device, readability past AA and the design tests live in core, and the components that use them are built against it, so each item now declares echo-ui-core >=0.3.0 <0.4.0. Update core with the items: npm install echo-ui-core@^0.3.0 (or your package manager's), then npx echo-ui-cli update. An item whose files didn't change is the same code under a new version; the 0.2.0 files stay published.
v0.2.0 · 2026-10-04 · AddedThe light device (echo-ui-core, echo-ui-cli). Echo can be light: a pale chassis makes a device molded in light plastic, like a white calculator or a cream radio, and a dark one makes the device Echo has always been. There's no setting and no mode to switch; the chassis decides (devicePolarity, and values.polarity on the theme). On a light device the page is light: its ground, the well, is the body barely set in. Caps get their own ladder, a step lighter than the body with a lit rim that stops short of white, so they keep their bevel; undersides and seams are shaded darker; dim text moves toward the ground by the same step as on a dark device, and reads about 6:1 on it. Screens are paper glass printed in ink, because a glow on a pale body is a smudge. What's lit (an LED, the current rail) is still the accent, held to 3:1 on every ground, so on is brighter than off; the text it prints (a readout, a count, a current tab) and the focus ring are the accent's ink, a step deeper and held to AA, in the new accent-ink role. The primary cap is the same cap as a dark device's, the accent with a light label: its label is the new primary-cap-ink role, and progress cells, loader dots and a meter's fill, the same plastic, read 3:1 on the page. A neutral cap or a slider that fills with it under its own dark label fills with the new pour-* roles, the accent's pale stops. Shadows are drawn at half their weight, in a deep colour of the body's own hue (--echo-cast-ink) instead of black. Every guarantee holds as it does on a dark device, and the contrast sweep now runs on light bodies too. A dark seed makes exactly the theme it did before, and the new roles equal the ones they stand for there. The components that mixed a recess toward black, painted paper in the text colour or lit a pillow of light with it read the theme's new --echo-shade-ink, --echo-paper-stock and --echo-paper-ink instead, with the old value as the fallback, and a reflective screen reads --echo-screen-*; the components that print a lit label read --echo-primary-cap-ink and --echo-accent-ink the same way; every rail is drawn in the glow, and every focus ring, the ring recipes included, in the ink. style use wears a light style now, and style check says which device a style makes. A dark screen tint on a light body is still refused: one text colour can't serve both, and the theme says so.
v0.2.0 · 2026-10-04 · AddedSegmentDisplay: a seven-segment readout that looks like a real one. The segments a reading doesn't light stay faintly visible under the glass, and zeros that only pad a reading out print dim instead of vanishing, so 88.5 on a four-digit face reads as a dim 0 and a lit 88.5. Digits, a minus, a decimal point, a colon and the few letters a segment face can draw; roll steps through the digits in between. It sits in its own dark well, or flush inside a screen you already have. Screen readers hear the reading once, as it is, with its unit.
v0.2.0 · 2026-10-04 · AddedReflective screens. screen="reflective" gives a screen the paper glass of a pocket calculator, printed in ink: digits, labels and ghost segments in the chassis colour, nothing glowing. The ink is held to AA on the glass under every theme. On SegmentDisplay, Tuner, Keypad, DateTile, NowPlaying, Annunciator and DescriptionList's screen.
v0.2.0 · 2026-10-04 · ChangedComponents whose shadow is a recipe read it by name. 71 shadows in 54 items now say var(--echo-shadow-<name>, <the same shadow>), so they look exactly as they did (every docs page was compared before and after) and follow a theme's recipes. Scope declares the recipes that read the accent again, so a Scope's own colour still reaches its focus rings and glows, and reflective screens do the same for theirs. Shadows that move with their part (a cap's drop as it's pressed) stay in the component.
v0.2.0 · 2026-10-04 · ChangedComments only, no behaviour change. Comments in the component source used to cite documents, milestones and ticket numbers from Echo's own planning, none of which exist in your project. The citations are gone and the sentences around them stay. Where a comment was only a citation, it now says what it meant. Three development warnings (HardwareButton's engraved/caption checks and StatusDot's missing-label check) also dropped the ticket code at the end of the message. echo-ui diff will show changes in most items; none of them are to code.
v0.2.0 · 2026-10-04 · ChangedAn item's version is now a function of declared data, not of how the changelog is formatted. The version an item ships under is published once and never rewritten, and it used to be inferred from prose: a regex for a bolded "Breaking" run across the whole unreleased section, and attribution by "does a bullet mention this name in backticks". One breaking entry therefore moved every item that changed that cycle, and an entry explaining that "Menu and Sheet are unchanged here" filed itself as a change to Menu and Sheet — which it really had.
v0.2.0 · 2026-10-04 · ChangedThe agent brief says Echo has not shipped. llms.txt and the MCP server's instructions led with npx echo-ui-cli init, and that name on npm is a reserved stub with no executable — so a model following the brief wrote an install step that fails with npx's own error. The brief now opens with the caveat, and the docs carry it on every surface that shows a command. One switch (CLI_RELEASED) silences all of them at launch, and a test refuses to let one move without the others. Affects all components only in what the brief says about installing them; no item's props, CSS or rendered semantics change.
v0.2.0 · 2026-10-04 · ChangedEcho's home is echo-ui.com. The registry, the docs and the packages all move to it from echo.nawwara.studio. Nothing was published under the old host, so no echo.json anywhere points at it and there is nothing to migrate — this is the last release where that is true.
v0.2.0 · 2026-10-04 · ChangedWeights, line heights, letter-spacing, z-index, border widths and icon sizes come from the theme scales in all components, with the old value as a fallback, so components keep working with echo-ui-core@0.0.1. Strays moved to the nearest step: most by under a pixel; HardwareButton icons are 14/16/20px (were 15/17/19).
v0.2.0 · 2026-10-04 · FixedA light device's recesses keep the body's hue in Chromium (echo-ui-core, BUG-166). Chromium drops the hue of a colour under 0.02 chroma when it mixes in oklch, and draws the mix at hue 0, a rose. A light device's plastic is that grey, so on a lilac body every field, track and rail was pink. A mix made only of greys is made in oklab now, which has no hue to lose; a mix with an accent in it stays in oklch. On a dark device nothing you can see changes.
v0.2.0 · 2026-10-04 · FixedContent now reflows into a 320px screen (400% zoom) and survives a doubled browser text size (WCAG 1.4.10, 1.4.4), across all components. Select's 180px floor, NumberField's readout, Segmented and Steps as flex items, EmptyState's grid columns, and Avatar's fixed-pixel disc all gave way; Panel counts its padding inside a width you set (box-sizing: border-box), so a <Panel style={{ width: 220 }}> is now 220px wide overall rather than 260px.

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