Updated with native ui (imgui + qt)

Client/WebUI/static/lttb-worker.js

@@ -0,0 +1,39 @@
+'use strict';
+// LTTB (Largest Triangle Three Buckets) decimation — O(n).
+// Runs off-main-thread to avoid blocking the render loop.
+function lttb(t, v, threshold) {
+  const len = t.length;
+  if (len <= threshold) {
+    // Copy to new arrays so we can transfer them back without detaching the input.
+    return { t: new Float64Array(t), v: new Float64Array(v) };
+  }
+  const outT = new Float64Array(threshold);
+  const outV = new Float64Array(threshold);
+  outT[0] = t[0]; outV[0] = v[0];
+  outT[threshold - 1] = t[len - 1]; outV[threshold - 1] = v[len - 1];
+  const every = (len - 2) / (threshold - 2);
+  let a = 0;
+  for (let i = 0; i < threshold - 2; i++) {
+    const avgS = Math.floor((i + 1) * every) + 1;
+    const avgE = Math.min(Math.floor((i + 2) * every) + 1, len);
+    let avgT = 0, avgV = 0, n = 0;
+    for (let j = avgS; j < avgE; j++) { avgT += t[j]; avgV += v[j]; n++; }
+    if (n) { avgT /= n; avgV /= n; }
+    const rS = Math.floor(i * every) + 1;
+    const rE = Math.min(Math.floor((i + 1) * every) + 1, len);
+    let maxA = -1, next = rS;
+    const aT = t[a], aV = v[a];
+    for (let j = rS; j < rE; j++) {
+      const area = Math.abs((aT - avgT) * (v[j] - aV) - (aT - t[j]) * (avgV - aV));
+      if (area > maxA) { maxA = area; next = j; }
+    }
+    outT[i + 1] = t[next]; outV[i + 1] = v[next]; a = next;
+  }
+  return { t: outT, v: outV };
+}
+
+self.onmessage = function({ data: { id, t, v, threshold } }) {
+  const result = lttb(t, v, threshold);
+  // Transfer the output buffers back to the main thread zero-copy.
+  self.postMessage({ id, t: result.t, v: result.v }, [result.t.buffer, result.v.buffer]);
+};