[feat](trx-frontend-http): migrate frontend canvas rendering to WebGL

Replace Canvas2D rendering in spectrum, overview, signal overlay, and CW tone picker with a shared WebGL renderer and wire the new asset into frontend HTTP routes.\n\nCo-authored-by: OpenAI Codex <codex@openai.com>

Signed-off-by: Stan Grams <sjg@haxx.space>
This commit is contained in:
2026-03-05 21:37:50 +01:00
parent 633ad92dd6
commit 27b90a62c5
8 changed files with 827 additions and 383 deletions
@@ -329,6 +329,12 @@ const loadingTitle = document.getElementById("loading-title");
const loadingSub = document.getElementById("loading-sub");
const overviewCanvas = document.getElementById("overview-canvas");
const signalOverlayCanvas = document.getElementById("signal-overlay-canvas");
const overviewGl = typeof createTrxWebGlRenderer === "function"
? createTrxWebGlRenderer(overviewCanvas, { alpha: true })
: null;
const signalOverlayGl = typeof createTrxWebGlRenderer === "function"
? createTrxWebGlRenderer(signalOverlayCanvas, { alpha: true })
: null;
const signalVisualBlockEl = document.querySelector(".signal-visual-block");
const signalSplitControlEl = document.getElementById("signal-split-control");
const signalSplitSliderEl = document.getElementById("signal-split-slider");
@@ -759,14 +765,19 @@ let overviewWaterfallRows = [];
let overviewWaterfallPushCount = 0; // monotonically increments on every push
const HEADER_SIG_WINDOW_MS = 10_000;
// Offscreen waterfall cache — reused across frames to avoid full redraws
let _wfOC = null; // OffscreenCanvas
let _wfOCPalKey = ""; // palette signature when offscreen was last built
let _wfOCPushCount = 0; // overviewWaterfallPushCount when offscreen was last updated
function cssColorToRgba(color, alphaMul = 1) {
const parser = typeof window.trxParseCssColor === "function" ? window.trxParseCssColor : null;
const parsed = parser ? parser(color) : [0, 0, 0, 1];
return [
parsed[0],
parsed[1],
parsed[2],
Math.max(0, Math.min(1, parsed[3] * alphaMul)),
];
}
function _wfResetOffscreen() { _wfOC = null; _wfOCPushCount = 0; _wfOCPalKey = ""; }
function _wfPalKey(pal) {
return `${pal.waterfallHue}|${pal.waterfallSat}|${pal.waterfallLight}|${pal.waterfallAlpha}`;
function rgbaWithAlpha(color, alphaMul = 1) {
return cssColorToRgba(color, alphaMul);
}
function resizeHeaderSignalCanvas() {
@@ -776,17 +787,13 @@ function resizeHeaderSignalCanvas() {
}
function ensureOverviewCanvasBackingStore() {
if (!overviewCanvas) return false;
if (!overviewCanvas || !overviewGl || !overviewGl.ready) return false;
const cssW = Math.floor(overviewCanvas.clientWidth);
const cssH = Math.floor(overviewCanvas.clientHeight);
if (cssW <= 0 || cssH <= 0) return false;
const dpr = window.devicePixelRatio || 1;
const nextW = Math.floor(cssW * dpr);
const nextH = Math.floor(cssH * dpr);
if (overviewCanvas.width !== nextW || overviewCanvas.height !== nextH) {
overviewCanvas.width = nextW;
overviewCanvas.height = nextH;
_wfResetOffscreen();
const resized = overviewGl.ensureSize(cssW, cssH, dpr);
if (resized) {
trimOverviewWaterfallRows();
}
return true;
@@ -809,7 +816,7 @@ function signalOverlayHeight() {
}
function drawSignalOverlay() {
if (!signalOverlayCanvas || !signalVisualBlockEl) return;
if (!signalOverlayCanvas || !signalVisualBlockEl || !signalOverlayGl || !signalOverlayGl.ready) return;
if (!lastSpectrumData) {
signalOverlayCanvas.style.height = "0";
signalOverlayCanvas.width = 0;
@@ -826,22 +833,19 @@ function drawSignalOverlay() {
}
const dpr = window.devicePixelRatio || 1;
const nextW = Math.floor(cssW * dpr);
const nextH = Math.floor(cssH * dpr);
if (signalOverlayCanvas.width !== nextW || signalOverlayCanvas.height !== nextH) {
signalOverlayCanvas.width = nextW;
signalOverlayCanvas.height = nextH;
}
const ctx = signalOverlayCanvas.getContext("2d");
if (!ctx) return;
ctx.save();
ctx.scale(dpr, dpr);
ctx.clearRect(0, 0, cssW, cssH);
signalOverlayGl.ensureSize(cssW, cssH, dpr);
const W = signalOverlayCanvas.width;
const H = signalOverlayCanvas.height;
if (W <= 0 || H <= 0) return;
signalOverlayGl.clear([0, 0, 0, 0]);
const range = spectrumVisibleRange(lastSpectrumData);
const hzToX = (hz) => ((hz - range.visLoHz) / range.visSpanHz) * cssW;
const hzToX = (hz) => ((hz - range.visLoHz) / range.visSpanHz) * W;
const bwSoft = cssColorToRgba("rgba(240,173,78,0.05)");
const bwMid = cssColorToRgba("rgba(240,173,78,0.19)");
const bwEdge = cssColorToRgba("rgba(240,173,78,0.30)");
const bwStroke = cssColorToRgba("rgba(240,173,78,0.70)");
const bwHard = cssColorToRgba("rgba(240,173,78,0.38)");
if (lastFreqHz != null && currentBandwidthHz > 0) {
for (const spec of visibleBandwidthSpecs(lastFreqHz)) {
@@ -850,71 +854,51 @@ function drawSignalOverlay() {
const xR = hzToX(span.hiHz);
const stripW = xR - xL;
if (stripW <= 1) continue;
const grd = ctx.createLinearGradient(xL, 0, xR, 0);
if (span.side < 0) {
grd.addColorStop(0, "rgba(240,173,78,0.05)");
grd.addColorStop(0.2, "rgba(240,173,78,0.14)");
grd.addColorStop(0.7, "rgba(240,173,78,0.19)");
grd.addColorStop(1, "rgba(240,173,78,0.19)");
signalOverlayGl.fillGradientRect(xL, 0, stripW, H, bwSoft, bwMid, bwMid, bwSoft);
} else if (span.side > 0) {
grd.addColorStop(0, "rgba(240,173,78,0.19)");
grd.addColorStop(0.3, "rgba(240,173,78,0.19)");
grd.addColorStop(0.8, "rgba(240,173,78,0.14)");
grd.addColorStop(1, "rgba(240,173,78,0.05)");
signalOverlayGl.fillGradientRect(xL, 0, stripW, H, bwMid, bwSoft, bwSoft, bwMid);
} else {
grd.addColorStop(0, "rgba(240,173,78,0.05)");
grd.addColorStop(0.2, "rgba(240,173,78,0.14)");
grd.addColorStop(0.5, "rgba(240,173,78,0.19)");
grd.addColorStop(0.8, "rgba(240,173,78,0.14)");
grd.addColorStop(1, "rgba(240,173,78,0.05)");
}
ctx.fillStyle = grd;
ctx.fillRect(xL, 0, stripW, cssH);
const edgeW = 5;
const edgeFill = "rgba(240,173,78,0.30)";
if (span.side <= 0) {
ctx.fillStyle = edgeFill;
ctx.fillRect(xL, 0, edgeW, cssH);
}
if (span.side >= 0) {
ctx.fillStyle = edgeFill;
ctx.fillRect(xR - edgeW, 0, edgeW, cssH);
const half = stripW / 2;
signalOverlayGl.fillGradientRect(xL, 0, half, H, bwSoft, bwMid, bwMid, bwSoft);
signalOverlayGl.fillGradientRect(xL + half, 0, half, H, bwMid, bwSoft, bwSoft, bwMid);
}
ctx.strokeStyle = "rgba(240,173,78,0.70)";
ctx.lineWidth = 1.5;
const edgeW = Math.max(1, Math.round(5 * dpr));
if (span.side <= 0) {
ctx.beginPath(); ctx.moveTo(xL, 0); ctx.lineTo(xL, cssH); ctx.stroke();
signalOverlayGl.fillRect(xL, 0, edgeW, H, bwEdge);
}
if (span.side >= 0) {
ctx.beginPath(); ctx.moveTo(xR, 0); ctx.lineTo(xR, cssH); ctx.stroke();
signalOverlayGl.fillRect(xR - edgeW, 0, edgeW, H, bwEdge);
}
if (span.side <= 0) {
signalOverlayGl.drawSegments([xL, 0, xL, H], bwStroke, Math.max(1, dpr * 1.5));
}
if (span.side >= 0) {
signalOverlayGl.drawSegments([xR, 0, xR, H], bwStroke, Math.max(1, dpr * 1.5));
}
if (span.side !== 0) {
ctx.strokeStyle = "rgba(240,173,78,0.38)";
ctx.lineWidth = 1;
const hardX = span.side < 0 ? xR : xL;
ctx.beginPath(); ctx.moveTo(hardX, 0); ctx.lineTo(hardX, cssH); ctx.stroke();
signalOverlayGl.drawSegments([hardX, 0, hardX, H], bwHard, Math.max(1, dpr));
}
}
}
if (lastFreqHz != null) {
const xf = hzToX(lastFreqHz);
if (xf >= 0 && xf <= cssW) {
ctx.save();
ctx.setLineDash([4, 4]);
ctx.strokeStyle = "#ff1744";
ctx.lineWidth = 1;
ctx.beginPath();
ctx.moveTo(xf, 0);
ctx.lineTo(xf, cssH);
ctx.stroke();
ctx.restore();
if (xf >= 0 && xf <= W) {
signalOverlayGl.drawDashedVerticalLine(
xf,
0,
H,
Math.max(2, Math.round(4 * dpr)),
Math.max(2, Math.round(4 * dpr)),
cssColorToRgba("#ff1744"),
Math.max(1, dpr),
);
}
}
ctx.restore();
}
function scheduleOverviewDraw() {
@@ -977,138 +961,93 @@ function startHeaderSignalSampling() {
function drawHeaderSignalGraph() {
if (!ensureOverviewCanvasBackingStore()) return;
const ctx = overviewCanvas.getContext("2d");
if (!ctx) return;
if (!overviewGl || !overviewGl.ready) return;
const pal = canvasPalette();
const dpr = window.devicePixelRatio || 1;
const w = overviewCanvas.width / dpr;
const h = overviewCanvas.height / dpr;
if (w <= 0 || h <= 0) return;
const W = overviewCanvas.width;
const H = overviewCanvas.height;
if (W <= 0 || H <= 0) return;
ctx.save();
ctx.scale(dpr, dpr);
ctx.clearRect(0, 0, w, h);
overviewGl.clear(cssColorToRgba(pal.bg));
if (lastSpectrumData && overviewWaterfallRows.length > 0) {
drawOverviewWaterfall(ctx, w, h, pal);
drawOverviewWaterfall(W, H, pal);
} else {
drawOverviewSignalHistory(ctx, w, h, pal);
drawOverviewSignalHistory(W, H, pal);
}
ctx.restore();
positionRdsPsOverlay();
drawSignalOverlay();
}
function _wfDrawRows(oct, rows, startRowIdx, endRowIdx, iW, iH, pal) {
// Draw rows[startRowIdx..endRowIdx) into oct, positioned at the canvas bottom.
// rowH is computed relative to the total row count (all of `rows`).
const total = rows.length;
const rowH = iH / total;
const columnStep = Math.max(1, Math.ceil(iW / 320));
for (let ri = startRowIdx; ri < endRowIdx; ri++) {
const bins = rows[ri];
if (!Array.isArray(bins) || bins.length === 0) continue;
const { startIdx, endIdx } = overviewVisibleBinWindow(lastSpectrumData, bins.length);
const spanBins = Math.max(1, endIdx - startIdx);
const y = iH - (total - ri) * rowH;
for (let x = 0; x < iW; x += columnStep) {
const frac = x / Math.max(1, iW - 1);
const binIdx = Math.min(endIdx, startIdx + Math.floor(frac * spanBins));
oct.fillStyle = waterfallColor(bins[binIdx], pal);
oct.fillRect(x, y, columnStep + 0.75, rowH + 1);
}
}
}
function drawOverviewWaterfall(ctx, w, h, pal) {
const maxVisible = Math.max(1, Math.floor(h));
function drawOverviewWaterfall(W, H, pal) {
if (!overviewGl || !overviewGl.ready) return;
const maxVisible = Math.max(1, Math.floor(H));
const rows = overviewWaterfallRows.slice(-maxVisible);
if (rows.length === 0) return;
const iW = Math.ceil(w);
const iH = Math.ceil(h);
const palKey = _wfPalKey(pal);
const steadyState = rows.length >= maxVisible;
// How many rows were pushed since the offscreen was last updated
const newPushes = overviewWaterfallPushCount - _wfOCPushCount;
const iW = Math.max(1, Math.ceil(W));
const iH = Math.max(1, Math.ceil(H));
const rgba = new Uint8Array(iW * iH * 4);
const minDb = Number.isFinite(spectrumFloor) ? spectrumFloor : -115;
const maxDb = minDb + Math.max(20, Number.isFinite(spectrumRange) ? spectrumRange : 90);
// Detect conditions that require a full redraw
const sizeChanged = !_wfOC || _wfOC.width !== iW || _wfOC.height !== iH;
const palChanged = _wfOCPalKey !== palKey;
const needsFull = sizeChanged || palChanged || _wfOCPushCount === 0;
if (sizeChanged || !_wfOC) {
_wfOC = new OffscreenCanvas(iW, iH);
_wfOCPushCount = 0;
}
const oct = _wfOC.getContext("2d");
if (needsFull) {
oct.clearRect(0, 0, iW, iH);
_wfDrawRows(oct, rows, 0, rows.length, iW, iH, pal);
_wfOCPushCount = overviewWaterfallPushCount;
_wfOCPalKey = palKey;
} else if (steadyState && newPushes > 0) {
// Steady state: scroll up and paint only the new rows at the bottom.
// newPushes new rows are at the tail of `rows`; each replaces one old row.
const newCount = Math.min(newPushes, rows.length);
const rowH = iH / rows.length;
const scrollPx = Math.round(newCount * rowH);
if (scrollPx > 0 && scrollPx < iH) {
const img = oct.getImageData(0, scrollPx, iW, iH - scrollPx);
oct.putImageData(img, 0, 0);
oct.clearRect(0, iH - scrollPx, iW, scrollPx);
for (let y = 0; y < iH; y++) {
const rowFrac = y / Math.max(1, iH - 1);
const rowIdx = Math.max(0, Math.min(rows.length - 1, Math.floor(rowFrac * rows.length)));
const bins = rows[rowIdx];
if (!Array.isArray(bins) || bins.length === 0) continue;
const { startIdx, endIdx } = overviewVisibleBinWindow(lastSpectrumData, bins.length);
const spanBins = Math.max(1, endIdx - startIdx);
for (let x = 0; x < iW; x++) {
const frac = x / Math.max(1, iW - 1);
const binIdx = Math.min(endIdx, startIdx + Math.floor(frac * spanBins));
const c = waterfallColorRgba(bins[binIdx], pal, minDb, maxDb);
const p = (y * iW + x) * 4;
rgba[p + 0] = Math.round(c[0] * 255);
rgba[p + 1] = Math.round(c[1] * 255);
rgba[p + 2] = Math.round(c[2] * 255);
rgba[p + 3] = Math.round(c[3] * 255);
}
_wfDrawRows(oct, rows, rows.length - newCount, rows.length, iW, iH, pal);
_wfOCPushCount = overviewWaterfallPushCount;
}
ctx.drawImage(_wfOC, 0, 0, w, h);
overviewGl.uploadRgbaTexture("overview-waterfall", iW, iH, rgba, "linear");
overviewGl.drawTexture("overview-waterfall", 0, 0, W, H, 1, true);
}
function drawOverviewSignalHistory(ctx, w, h, pal) {
function drawOverviewSignalHistory(W, H, pal) {
if (!overviewGl || !overviewGl.ready) return;
const now = Date.now();
const samples = overviewSignalSamples.filter((sample) => now - sample.t <= HEADER_SIG_WINDOW_MS);
if (samples.length === 0) return;
const maxVal = 20;
const windowStart = now - HEADER_SIG_WINDOW_MS;
const toX = (t) => ((t - windowStart) / HEADER_SIG_WINDOW_MS) * w;
const toY = (v) => h - (Math.max(0, Math.min(maxVal, v)) / maxVal) * (h - 3) - 1.5;
const toX = (t) => ((t - windowStart) / HEADER_SIG_WINDOW_MS) * W;
const toY = (v) => H - (Math.max(0, Math.min(maxVal, v)) / maxVal) * (H - 3) - 1.5;
const gridMarkers = [
{ val: 0, label: "S0" },
{ val: 9, label: "S9" },
{ val: 18, label: "S9+" },
{ val: 0 },
{ val: 9 },
{ val: 18 },
];
ctx.strokeStyle = pal.waveformGrid;
ctx.lineWidth = 1;
ctx.font = "11px sans-serif";
ctx.fillStyle = pal.waveformLabel;
ctx.textAlign = "right";
ctx.textBaseline = "middle";
const gridSegments = [];
for (const marker of gridMarkers) {
const y = toY(marker.val);
ctx.beginPath();
ctx.moveTo(0, y);
ctx.lineTo(w, y);
ctx.stroke();
ctx.fillText(marker.label, w - 6, Math.max(8, Math.min(h - 8, y + 6)));
gridSegments.push(0, y, W, y);
}
overviewGl.drawSegments(gridSegments, cssColorToRgba(pal.waveformGrid), 1);
ctx.beginPath();
const linePoints = [];
samples.forEach((sample, idx) => {
const x = toX(sample.t);
const y = toY(sample.v);
if (idx === 0) ctx.moveTo(x, y);
else ctx.lineTo(x, y);
if (idx === 0 || x >= linePoints[linePoints.length - 2]) {
linePoints.push(x, y);
}
});
ctx.strokeStyle = pal.waveformLine;
ctx.lineWidth = 1.6;
ctx.stroke();
overviewGl.drawPolyline(linePoints, cssColorToRgba(pal.waveformLine), 1.6);
const holdMs = Math.max(0, Number.isFinite(overviewPeakHoldMs) ? overviewPeakHoldMs : 0);
if (holdMs > 0) {
ctx.beginPath();
const holdPoints = [];
for (let i = 0; i < samples.length; i++) {
let peak = samples[i].v;
for (let j = i; j >= 0; j--) {
@@ -1117,26 +1056,28 @@ function drawOverviewSignalHistory(ctx, w, h, pal) {
}
const x = toX(samples[i].t);
const y = toY(peak);
if (i === 0) ctx.moveTo(x, y);
else ctx.lineTo(x, y);
if (i === 0 || x >= holdPoints[holdPoints.length - 2]) {
holdPoints.push(x, y);
}
}
ctx.strokeStyle = pal.waveformPeak;
ctx.lineWidth = 1;
ctx.stroke();
overviewGl.drawPolyline(holdPoints, cssColorToRgba(pal.waveformPeak), 1);
}
}
function waterfallColor(db, pal) {
const minDb = Number.isFinite(spectrumFloor) ? spectrumFloor : -115;
const maxDb = minDb + Math.max(20, Number.isFinite(spectrumRange) ? spectrumRange : 90);
const safeDb = Number.isFinite(db) ? db : minDb;
const clamped = Math.max(minDb, Math.min(maxDb, safeDb));
const span = Math.max(1, maxDb - minDb);
const t = (clamped - minDb) / span;
function waterfallColorRgba(db, pal, minDb, maxDb) {
const lo = Number.isFinite(minDb) ? minDb : (Number.isFinite(spectrumFloor) ? spectrumFloor : -115);
const hi = Number.isFinite(maxDb) ? maxDb : (lo + Math.max(20, Number.isFinite(spectrumRange) ? spectrumRange : 90));
const safeDb = Number.isFinite(db) ? db : lo;
const clamped = Math.max(lo, Math.min(hi, safeDb));
const span = Math.max(1, hi - lo);
const t = (clamped - lo) / span;
const hue = pal.waterfallHue[0] + t * (pal.waterfallHue[1] - pal.waterfallHue[0]);
const light = pal.waterfallLight[0] + t * (pal.waterfallLight[1] - pal.waterfallLight[0]);
const alpha = pal.waterfallAlpha[0] + t * (pal.waterfallAlpha[1] - pal.waterfallAlpha[0]);
return `hsla(${hue}, ${pal.waterfallSat}%, ${light}%, ${alpha})`;
if (typeof window.trxHslToRgba === "function") {
return window.trxHslToRgba(hue, pal.waterfallSat, light, alpha);
}
return cssColorToRgba(`hsla(${hue}, ${pal.waterfallSat}%, ${light}%, ${alpha})`);
}
function formatFreq(hz) {
@@ -5873,6 +5814,10 @@ window.addEventListener("beforeunload", () => {
// ── Spectrum display ─────────────────────────────────────────────────────────
const spectrumCanvas = document.getElementById("spectrum-canvas");
const spectrumGl = typeof createTrxWebGlRenderer === "function"
? createTrxWebGlRenderer(spectrumCanvas, { alpha: true })
: null;
const spectrumDbAxis = document.getElementById("spectrum-db-axis");
const spectrumFreqAxis = document.getElementById("spectrum-freq-axis");
const spectrumTooltip = document.getElementById("spectrum-tooltip");
const spectrumCenterLeftBtn = document.getElementById("spectrum-center-left-btn");
@@ -5881,6 +5826,7 @@ let spectrumSource = null;
let spectrumReconnectTimer = null;
let spectrumDrawPending = false;
let spectrumAxisKey = "";
let spectrumDbAxisKey = "";
let lastSpectrumRenderData = null;
let spectrumPeakHoldFrames = [];
let pendingSpectrumFrameWaiters = [];
@@ -6198,7 +6144,6 @@ function startSpectrumStreaming() {
clearSpectrumPeakHoldFrames();
overviewWaterfallRows = [];
overviewWaterfallPushCount = 0;
_wfResetOffscreen();
scheduleOverviewDraw();
clearSpectrumCanvas();
updateRdsPsOverlay(null);
@@ -6247,7 +6192,6 @@ function stopSpectrumStreaming() {
clearSpectrumPeakHoldFrames();
overviewWaterfallRows = [];
overviewWaterfallPushCount = 0;
_wfResetOffscreen();
scheduleOverviewDraw();
updateRdsPsOverlay(null);
clearSpectrumCanvas();
@@ -6255,10 +6199,15 @@ function stopSpectrumStreaming() {
// ── Rendering ────────────────────────────────────────────────────────────────
function clearSpectrumCanvas() {
if (!spectrumCanvas) return;
const ctx = spectrumCanvas.getContext("2d");
ctx.fillStyle = spectrumBgColor();
ctx.fillRect(0, 0, spectrumCanvas.width, spectrumCanvas.height);
if (!spectrumCanvas || !spectrumGl || !spectrumGl.ready) return;
const cssW = spectrumCanvas.clientWidth || 1;
const cssH = spectrumCanvas.clientHeight || 1;
spectrumGl.ensureSize(cssW, cssH, window.devicePixelRatio || 1);
spectrumGl.clear(cssColorToRgba(spectrumBgColor()));
if (spectrumDbAxis) {
spectrumDbAxis.innerHTML = "";
spectrumDbAxisKey = "";
}
}
function formatOverlayPs(ps) {
@@ -6550,167 +6499,73 @@ function scheduleSpectrumDraw() {
}
function drawSpectrum(data) {
if (!spectrumCanvas) return;
if (!spectrumCanvas || !spectrumGl || !spectrumGl.ready) return;
// HiDPI sizing
const dpr = window.devicePixelRatio || 1;
const cssW = spectrumCanvas.clientWidth || 640;
const dpr = window.devicePixelRatio || 1;
const cssW = spectrumCanvas.clientWidth || 640;
const cssH = spectrumCanvas.clientHeight || 160;
const W = Math.round(cssW * dpr);
const H = Math.round(cssH * dpr);
if (spectrumCanvas.width !== W || spectrumCanvas.height !== H) {
spectrumCanvas.width = W;
spectrumCanvas.height = H;
}
spectrumGl.ensureSize(cssW, cssH, dpr);
const W = spectrumCanvas.width;
const H = spectrumCanvas.height;
const ctx = spectrumCanvas.getContext("2d");
const pal = canvasPalette();
const pal = canvasPalette();
const range = spectrumVisibleRange(data);
const bins = data.bins;
const bins = data.bins;
const peakHoldBins = buildSpectrumPeakHoldBins(bins);
const n = bins.length;
// Background
ctx.fillStyle = pal.bg;
ctx.fillRect(0, 0, W, H);
const n = bins.length;
spectrumGl.clear(cssColorToRgba(pal.bg));
if (!n) return;
const DB_MIN = spectrumFloor;
const DB_MAX = spectrumFloor + spectrumRange;
const DB_MIN = spectrumFloor;
const DB_MAX = spectrumFloor + spectrumRange;
const dbRange = DB_MAX - DB_MIN;
const fullSpanHz = data.sample_rate;
const loHz = data.center_hz - fullSpanHz / 2;
const loHz = data.center_hz - fullSpanHz / 2;
// Horizontal dB grid lines
ctx.strokeStyle = pal.spectrumGrid;
ctx.lineWidth = 1;
const gridStep = spectrumRange > 100 ? 20 : 10;
const gridSegments = [];
for (let db = Math.ceil(DB_MIN / gridStep) * gridStep; db <= DB_MAX; db += gridStep) {
const y = Math.round(H * (1 - (db - DB_MIN) / dbRange));
ctx.beginPath(); ctx.moveTo(0, y); ctx.lineTo(W, y); ctx.stroke();
gridSegments.push(0, y, W, y);
}
spectrumGl.drawSegments(gridSegments, cssColorToRgba(pal.spectrumGrid), 1);
updateSpectrumDbAxis(DB_MIN, DB_MAX, gridStep, H, dpr);
// Y-axis dB labels (left side)
ctx.save();
ctx.font = `${Math.round(9 * dpr)}px monospace`;
ctx.fillStyle = pal.spectrumLabel;
ctx.textAlign = "left";
for (let db = Math.ceil(DB_MIN / gridStep) * gridStep; db <= DB_MAX; db += gridStep) {
const y = Math.round(H * (1 - (db - DB_MIN) / dbRange));
if (y > 8 * dpr && y < H - 2 * dpr) {
ctx.fillText(`${db}`, 4 * dpr, y - 2 * dpr);
}
}
ctx.restore();
// Coordinate helpers
function hzToX(hz) {
return ((hz - range.visLoHz) / range.visSpanHz) * W;
}
function binX(i) {
return hzToX(loHz + (i / (n - 1)) * fullSpanHz);
}
function binY(i) {
const db = Math.max(DB_MIN, Math.min(DB_MAX, bins[i]));
function binYFromBins(srcBins, i) {
const db = Math.max(DB_MIN, Math.min(DB_MAX, srcBins[i]));
return H * (1 - (db - DB_MIN) / dbRange);
}
// ── BW strip (drawn before spectrum so traces appear on top) ──────────────
if (lastFreqHz != null && currentBandwidthHz > 0) {
if (_bwDragEdge) {
// Bottom bookmark tab centered on each visible channel, shown while resizing BW
const bwText = formatBwLabel(currentBandwidthHz);
for (const spec of visibleBandwidthSpecs(lastFreqHz)) {
const xMid = hzToX(spec.centerHz);
ctx.save();
ctx.font = `bold ${Math.round(10 * dpr)}px sans-serif`;
const tw = ctx.measureText(bwText).width;
const PAD = 6 * dpr;
const TAB_H = 16 * dpr;
const TAB_OFFSET = 4 * dpr;
const tabX = Math.max(0, Math.min(W - tw - PAD * 2, xMid - (tw + PAD * 2) / 2));
const tabBottom = H - TAB_OFFSET;
const tabY = tabBottom - TAB_H;
const r = 3 * dpr;
// Rounded-bottom tab shape (flat top)
ctx.fillStyle = "rgba(240,173,78,0.85)";
ctx.beginPath();
ctx.moveTo(tabX, tabY);
ctx.lineTo(tabX + tw + PAD * 2, tabY);
ctx.lineTo(tabX + tw + PAD * 2, tabBottom - r);
ctx.arcTo(tabX + tw + PAD * 2, tabBottom, tabX + tw + PAD * 2 - r, tabBottom, r);
ctx.lineTo(tabX + r, tabBottom);
ctx.arcTo(tabX, tabBottom, tabX, tabBottom - r, r);
ctx.lineTo(tabX, tabY);
ctx.closePath();
ctx.fill();
// Tab text
ctx.fillStyle = spectrumBgColor();
ctx.textAlign = "left";
ctx.fillText(bwText, tabX + PAD, tabBottom - 4 * dpr);
ctx.restore();
}
}
}
// ── Spectrum fill ─────────────────────────────────────────────────────────
ctx.save();
ctx.beginPath();
ctx.moveTo(binX(0), H);
for (let i = 0; i < n; i++) ctx.lineTo(binX(i), binY(i));
ctx.lineTo(binX(n - 1), H);
ctx.closePath();
ctx.fillStyle = pal.spectrumFill;
ctx.fill();
ctx.restore();
// ── Peak-hold shadow ───────────────────────────────────────────────────────
if (Array.isArray(peakHoldBins) && peakHoldBins.length === n) {
ctx.save();
ctx.beginPath();
ctx.strokeStyle = pal.waveformPeak;
ctx.globalAlpha = 0.7;
ctx.lineWidth = Math.max(1, dpr * 0.9);
for (let i = 0; i < n; i++) {
const x = binX(i);
const db = Math.max(DB_MIN, Math.min(DB_MAX, peakHoldBins[i]));
const y = H * (1 - (db - DB_MIN) / dbRange);
i === 0 ? ctx.moveTo(x, y) : ctx.lineTo(x, y);
}
ctx.stroke();
ctx.restore();
}
// ── Spectrum line ─────────────────────────────────────────────────────────
ctx.save();
ctx.beginPath();
ctx.strokeStyle = pal.spectrumLine;
ctx.lineWidth = Math.max(1, dpr);
const fillPoints = [];
for (let i = 0; i < n; i++) {
const x = binX(i), y = binY(i);
i === 0 ? ctx.moveTo(x, y) : ctx.lineTo(x, y);
fillPoints.push(binX(i), binYFromBins(bins, i));
}
ctx.stroke();
ctx.restore();
spectrumGl.drawFilledArea(fillPoints, H, cssColorToRgba(pal.spectrumFill));
if (Array.isArray(peakHoldBins) && peakHoldBins.length === n) {
const peakPoints = [];
for (let i = 0; i < n; i++) {
peakPoints.push(binX(i), binYFromBins(peakHoldBins, i));
}
spectrumGl.drawPolyline(peakPoints, rgbaWithAlpha(pal.waveformPeak, 0.7), Math.max(1, dpr * 0.9));
}
spectrumGl.drawPolyline(fillPoints, cssColorToRgba(pal.spectrumLine), Math.max(1, dpr));
// ── Peak markers for easier snap-tune targeting ──────────────────────────
const markerPeaks = visibleSpectrumPeakIndices(data);
if (markerPeaks.length > 0) {
ctx.save();
ctx.fillStyle = pal.waveformPeak;
ctx.strokeStyle = pal.bg;
ctx.lineWidth = Math.max(1, dpr * 0.75);
const radius = Math.max(2, dpr * 1.6);
const markerPoints = [];
for (const idx of markerPeaks) {
const x = binX(idx);
const y = binY(idx);
ctx.beginPath();
ctx.arc(x, y - radius * 0.35, radius, 0, Math.PI * 2);
ctx.fill();
ctx.stroke();
markerPoints.push(binX(idx), binYFromBins(bins, idx));
}
ctx.restore();
spectrumGl.drawPoints(markerPoints, Math.max(2, dpr * 1.6), cssColorToRgba(pal.waveformPeak));
}
updateSpectrumFreqAxis(range);
@@ -6960,6 +6815,34 @@ function updateSpectrumFreqAxis(range) {
}
}
function updateSpectrumDbAxis(dbMin, dbMax, gridStep, heightPx, dpr) {
if (!spectrumDbAxis) return;
const key = [
Math.round(dbMin),
Math.round(dbMax),
Math.round(gridStep),
Math.round(heightPx),
Math.round((dpr || 1) * 100),
currentTheme(),
currentStyle(),
].join(":");
if (key === spectrumDbAxisKey) return;
spectrumDbAxisKey = key;
spectrumDbAxis.innerHTML = "";
const spanDb = Math.max(1, dbMax - dbMin);
const cssHeight = heightPx / Math.max(1, dpr || 1);
for (let db = Math.ceil(dbMin / gridStep) * gridStep; db <= dbMax; db += gridStep) {
const yPx = Math.round(heightPx * (1 - (db - dbMin) / spanDb));
const yCss = yPx / Math.max(1, dpr || 1);
if (yCss <= 7 || yCss >= cssHeight - 4) continue;
const span = document.createElement("span");
span.textContent = `${db}`;
span.style.top = `${yCss}px`;
spectrumDbAxis.appendChild(span);
}
}
// ── Zoom helpers ──────────────────────────────────────────────────────────────
function spectrumZoomAt(cssX, cssW, data, factor) {
const range = spectrumVisibleRange(data);