ov-cellbar

src/ov-ascii.js

Attributes

attribute
`cells`
`max`
`min`
`source`
`unit`
`value`	also a property

Properties

A reading property takes a reading directly, which an attribute cannot: an attribute is a string, and a reading may be an array, a dropout, or a value carrying an age.

property	type	kind	accepts	staleness
`value`	`Reading`	reading	a single reading	does not mark stale

WHAT A READING PROPERTY ACCEPTS

set to	what happens
`null`	set deliberately to nothing. A dropout, renders a refusal
`number`	drawn
`undefined`	property never set; falls through to source, then attribute

A reading property never coerces null to 0 and never drops it from an array. Strings are passed through unnormalised, so "01.50" stays "01.50".

This readout does not mark staleness. It has no common() path, so a reading carrying an age is drawn without a stale qualifier.

Events

None.

Using it

import 'overscan'
import 'overscan/overscan.css'

<div class="strip">
  <ov-cellbar
    value="62"
    min="0"
    max="100"
    cells="10"
    unit="%"
  >
  </ov-cellbar>
  <ov-cellbar
    value="134"
    min="0"
    max="100"
    cells="10"
    unit="%"
  >
  </ov-cellbar>
  <ov-cellbar
    value=""
    min="0"
    max="100"
    cells="10"
    unit="%"
  >
  </ov-cellbar>
</div>

import { OvCellbar } from 'overscan/react'

<OvCellbar
  min="0"
  max="100"
  cells="10"
  unit="%"
  value={reading}
/>

import { OvCellbar } from 'overscan/vue'

<OvCellbar
  min="0"
  max="100"
  cells="10"
  unit="%"
  :value="reading"
/>

import OvCellbar from 'overscan/svelte/OvCellbar.svelte'

<OvCellbar
  min="0"
  max="100"
  cells="10"
  unit="%"
  value={reading}
/>

The CSS is a separate import in every framework. A single element can be imported on its own instead of the whole kit: import 'overscan/src/ov-chart.js'

A reading is set as a PROPERTY, never an attribute. An attribute is a string, so an array cannot survive one and a null arrives as the word "null", which the protocol would read as a value rather than a dropout.

Every ov: event is bound with addEventListener. The colon has no declarative spelling in Svelte 5, where the on: directive is gone and "onov:commit" is not an identifier, nor in JSX. Vue can bind it.

The wrapper applies attributes ITSELF and hands the framework nothing but a ref. All three frameworks set a prop as a property when the name exists on the element, and this kit has 72 getter-only properties across 39 elements. Assigning one throws, and in React it does not degrade: the whole tree fails to render. 13 elements have a getter-only name that is also a real attribute (at, bearing, digits, duration, floor, fov, fresh, hold, lat, lon, period, pitch, range, ring, rings, span, step, sweep, sweeps, traces, value), which are the ones a reader would naturally pass in markup.