64:I[314491,["/_next/static/immutable/chunks/3arlv5bvukoo2.js","/_next/static/immutable/chunks/39v64hmfyo-sr.js","/_next/static/immutable/chunks/2nvof3-29tvc3.js","/_next/static/immutable/chunks/3tjobt77z_9dj.js","/_next/static/immutable/chunks/04j_o97cgxn2x.js","/_next/static/immutable/chunks/3upr08c9vtj8w.js","/_next/static/immutable/chunks/1ww0328si-u8x.js","/_next/static/immutable/chunks/11mfl5ymqld9-.js","/_next/static/immutable/chunks/2xxcqy6ppds3l.js","/_next/static/immutable/chunks/1bpgyrs5qflhu.js","/_next/static/immutable/chunks/0-6vu2ul1h6ld.js","/_next/static/immutable/chunks/43_s7jweyypoh.js","/_next/static/immutable/chunks/0p6vao205o1jc.js","/_next/static/immutable/chunks/1_kyvgkyokw92.js","/_next/static/immutable/chunks/1lo-zn37dolb5.js","/_next/static/immutable/chunks/1v8k6yxw1rg0u.js"],"FilesView"] 65:T2cec,"use client"; import { useEffect, useRef } from "react"; // --------------------------------------------------------------------------- // MeterMatrixScan — a level meter rendered as a genuinely row-multiplexed // LED dot-matrix panel. // // SOURCE, NOT INVENTED: cheap commercial LED dot-matrix signage (scrolling // ticker boards, gym scoreboards, elevator floor indicators, budget // character displays built on row/column multiplex driver chips) can't // afford one continuous driver per LED. Instead the panel scans one row at // a time at a frequency well above human flicker fusion, relying on // persistence of vision to read a complete static image, and within each // row's brief active slice an individual LED's apparent brightness is set // by PWM (pulse-width modulation) duty cycle — fully on or fully off at any // instant, perceived brightness being the fraction of the row's active // window it spends on, quantized to a small number of duty steps. That // quantized time-division duty cycle (not a continuous alpha/density value) // is this component's entire identity, distinct from every other // ASCII/glyph-luminance component in the registry. // // THE ROW-SCAN ARTIFACT: a real multiplex board's per-row scan is invisible // at rest — that's the whole point of persistence of vision. It only ever // becomes visible when something samples the panel at a rate that doesn't // divide evenly into its own full-panel refresh, e.g. filming an LED sign // with a camera whose shutter/frame rate doesn't line up with the panel's // scan rate produces a soft band drifting through the image (the reason // dashcam footage sometimes shows a faint bar through LED signage). A literal // 1:1 real-time render of the raw ROW_SCAN_HZ clock against a ~60Hz browser // paint rate aliases close enough to the paint rate itself to read as a hard // strobe/flicker — a rendering-pipeline artifact, not the calm hardware // phenomenon it's meant to represent. So the scan address (ROW_SCAN_HZ, // documented below, is the real underlying clock) is deliberately mapped onto // a slow, continuous sweep position instead of a discrete per-frame row // index: a soft brightness gradient a couple of rows wide, low amplitude, // drifting the full height of the panel and back over several seconds — the // same round-robin row addressing concept, legible on a second look, without // ever strobing near the paint rate. // --------------------------------------------------------------------------- const ROWS = 5; const ROW_SCAN_HZ = 240; // real per-row multiplex clock this component represents const PWM_LEVELS = 8; // 3-bit duty-cycle depth const GUTTER_PX = 3; // gap between dots, ~2-4px per spec const SWEEP_PERIOD_S = 7.5; // one full down-and-back sweep across the panel const SWEEP_SIGMA_ROWS = 1.4; // gradient softness, in rows — wide, not a 1-row strip const SCAN_HIGHLIGHT_ALPHA = 0.055; // luminance-only, low-amplitude boost at the sweep's center const MIN_ON_ALPHA = 0.16; // floor so PWM band 1/8 never rounds to invisible in light theme // slow generative "sensor" field used only when no external `value` prop is // supplied — three non-commensurate traveling sine components, amplitude // bounded so the simulated reading stays comfortably inside 0..100. function sensorValue(t: number) { const f = Math.sin(t * 0.17) + 0.5 * Math.sin(t * 0.43 + 1.3) + 0.3 * Math.sin(t * 0.08 + 2.1); const norm = f / 1.8; // amplitude sum 1.8 -> -1..1 return 55 + norm * 32; // ~23..87 } // continuous sweep position, in row units (0..ROWS-1), a slow triangle wave // so the drift is smooth and reverses without a jump-cut at either end function sweepPosition(t: number) { const phase = (t % SWEEP_PERIOD_S) / SWEEP_PERIOD_S; // 0..1 const tri = phase < 0.5 ? phase * 2 : 2 - phase * 2; // 0 -> 1 -> 0 return tri * (ROWS - 1); } export interface MeterMatrixScanProps { /** current level, 0..max. Omit to drive the meter from an internal simulated sensor read. */ value?: number; /** domain ceiling for value. Default 100. */ max?: number; /** accessible name for the reading, e.g. "CPU load". Default "Level". */ label?: string; /** panel height in px; ROWS=5 fixed, cell size derives as height / 5. Default 60. */ height?: number; /** extra classes merged onto the rendered root element */ className?: string; } export function MeterMatrixScan({ value, max = 100, label = "Level", height = 60, className = "", }: MeterMatrixScanProps) { const canvasRef = useRef(null); const wrapperRef = useRef(null); const valueRef = useRef(value); valueRef.current = value; useEffect(() => { const canvas = canvasRef.current; const wrapper = wrapperRef.current; if (!canvas || !wrapper) return; const ctx = canvas.getContext("2d"); if (!ctx) return; const reduced = window.matchMedia("(prefers-reduced-motion: reduce)").matches; let bg = ""; let fg = ""; const cellSize = Math.max(2, height / ROWS); const radius = Math.max(1, (cellSize - GUTTER_PX) / 2); let cols = 0; let sized = false; let lastWidth = 0; const readTokens = () => { const root = getComputedStyle(document.documentElement); // fallbacks are CSS keywords, never literal colour values bg = root.getPropertyValue("--background").trim() || "transparent"; fg = root.getPropertyValue("--foreground").trim() || "currentColor"; }; const resize = () => { const { width } = canvas.getBoundingClientRect(); if (width < 2) { sized = false; return; } if (sized && Math.abs(width - lastWidth) < 1) return; lastWidth = width; const dpr = Math.min(window.devicePixelRatio || 1, 2); canvas.width = Math.max(1, Math.round(width * dpr)); canvas.height = Math.max(1, Math.round(height * dpr)); ctx.setTransform(dpr, 0, 0, dpr, 0, 0); cols = Math.max(6, Math.floor(width / cellSize)); sized = true; }; // globalT: seconds, drives both the simulated sensor field (when // `value` is uncontrolled) and the sweep position. Never resets. let globalT = 0; const currentValue = () => { const external = valueRef.current; const v = external === undefined ? sensorValue(globalT) : external; return Math.min(max, Math.max(0, v)); }; const draw = (sweepPos: number | null) => { if (!sized) return; const w = cols * cellSize; ctx.clearRect(0, 0, w, height); ctx.fillStyle = bg; ctx.fillRect(0, 0, w, height); const filled = (currentValue() / max) * cols; const fullCols = Math.min(cols, Math.floor(filled)); const frac = filled - fullCols; // fractional boundary LED's brightness is a literal quantized PWM // duty step, never a smooth alpha ramp const boundaryLevel = Math.round(frac * PWM_LEVELS); for (let r = 0; r < ROWS; r++) { const cy = r * cellSize + cellSize / 2; // soft Gaussian weight of this row against the sweep's current // center — a wide, low-amplitude bump, not a hard on/off strip, so // several rows share a gentle gradient rather than one strobing let sweepBoost = 0; if (sweepPos !== null) { const d = r - sweepPos; sweepBoost = SCAN_HIGHLIGHT_ALPHA * Math.exp(-(d * d) / (2 * SWEEP_SIGMA_ROWS * SWEEP_SIGMA_ROWS)); } for (let c = 0; c < cols; c++) { let level = 0; if (c < fullCols) level = PWM_LEVELS; else if (c === fullCols) level = boundaryLevel; if (level <= 0) continue; let alpha = level / PWM_LEVELS; alpha = Math.max(MIN_ON_ALPHA, alpha); alpha = Math.min(1, alpha + sweepBoost); const cx = c * cellSize + cellSize / 2; ctx.globalAlpha = alpha; ctx.fillStyle = fg; ctx.beginPath(); ctx.arc(cx, cy, radius, 0, Math.PI * 2); ctx.fill(); } // the same soft gradient laid across only the off (background) // columns of this row — what makes the sweep legible independent of // the value fill, luminance only, never a hard band. Confined to the // unlit region so it never stacks on top of an already-boosted dot. const offStartX = Math.min(w, (fullCols + 1) * cellSize); if (sweepBoost > 0.002 && offStartX < w) { ctx.globalAlpha = sweepBoost * 0.7; ctx.fillStyle = fg; ctx.fillRect(offStartX, r * cellSize, w - offStartX, cellSize); } } ctx.globalAlpha = 1; wrapper.setAttribute("aria-valuenow", String(Math.round(currentValue()))); }; // -- loop ---------------------------------------------------------------- let raf = 0; let last = 0; const loop = (now: number) => { const dtMs = last ? Math.min(250, now - last) : 1000 / 60; last = now; globalT += dtMs / 1000; draw(sweepPosition(globalT)); if (!document.hidden) raf = requestAnimationFrame(loop); }; const mo = new MutationObserver(() => { readTokens(); if (reduced) draw(null); }); mo.observe(document.documentElement, { attributes: true, attributeFilter: ["class"], }); let resizeTimer: ReturnType | null = null; const onResize = () => { if (resizeTimer) clearTimeout(resizeTimer); resizeTimer = setTimeout(() => { resizeTimer = null; readTokens(); resize(); draw(reduced ? null : sweepPosition(globalT)); }, 150); }; const ro = new ResizeObserver(onResize); ro.observe(canvas); const io = new IntersectionObserver( (entries) => { const visible = entries[0]?.isIntersecting; if (visible && !reduced && sized) { cancelAnimationFrame(raf); last = 0; raf = requestAnimationFrame(loop); } else if (!visible) { cancelAnimationFrame(raf); } }, { threshold: 0 } ); io.observe(canvas); const onVis = () => { cancelAnimationFrame(raf); if (!document.hidden && !reduced && sized) { last = 0; raf = requestAnimationFrame(loop); } }; document.addEventListener("visibilitychange", onVis); // no paint before the first token read readTokens(); resize(); if (reduced) { // freeze with the sweep locked off entirely — no gradient visible, // every row rendered as if simultaneously lit at its true duty level — // at a value past the field's cold-start instant, same convention as // this registry's other generative components. globalT = 1.4; draw(null); } else { draw(sweepPosition(globalT)); raf = requestAnimationFrame(loop); } return () => { cancelAnimationFrame(raf); if (resizeTimer) clearTimeout(resizeTimer); mo.disconnect(); ro.disconnect(); io.disconnect(); document.removeEventListener("visibilitychange", onVis); }; }, [height, max]); return (

); } 63:["$","div",null,{"className":"mt-3 flex min-h-0 min-w-0 flex-1 flex-col gap-3","children":[null,["$","$L64",null,{"files":[{"path":"registry/core/meter-matrix-scan/component.tsx","content":"$65","type":"registry:ui","target":"components/ui/meter-matrix-scan.tsx"}],"className":"h-[70svh] min-h-80"}]]}]