Downsample in Plots only >30s

Author: haoruizhou

pecan/src/components/PlotManager.tsx

@@ -15,16 +15,10 @@ const PLOT_COLORS = [
   "#00bbcc",
 ];
 
-// Helper to calculate downsample resolution based on time window
-function calculateDownsampleResolution(windowMs: number): number {
-  // Under 3s (3000ms), use 200ms resolution
-  if (windowMs <= 3000) return 200;
-  // Above 20s (20000ms), use 1000ms resolution
-  if (windowMs >= 20000) return 1000;
-
-  // Linear interpolation between 3000ms and 20000ms
-  // Range: 17000ms. Value range: 800ms.
-  return 200 + ((windowMs - 3000) / 17000) * 800;
+// Returns downsample resolution in ms, or null for no downsampling (raw points).
+function calculateDownsampleResolution(windowMs: number): number | null {
+  if (windowMs <= 30000) return null;
+  return 100;
 }
 
 export interface PlotSignal {
@@ -171,43 +165,44 @@ function PlotManager({
         const yData: number[] = [];
 
         if (history.length > 0) {
-          let currentBinStart =
-            Math.floor(history[0].timestamp / resolution) * resolution;
-          let currentSum = 0;
-          let currentCount = 0;
-
-          for (const sample of history) {
-            const signalData = sample.data[signal.signalName];
-            if (signalData === undefined) continue;
-
-            const sampleBin =
-              Math.floor(sample.timestamp / resolution) * resolution;
-
-            if (sampleBin === currentBinStart) {
-              currentSum += signalData.sensorReading;
-              currentCount++;
-            } else {
-              // Finalize previous bin
-              if (currentCount > 0) {
-                const avg = currentSum / currentCount;
-                const x = (currentBinStart - windowEndMs) / 1000;
-                xData.push(x);
-                yData.push(avg);
+          if (resolution === null) {
+            for (const sample of history) {
+              const signalData = sample.data[signal.signalName];
+              if (signalData === undefined) continue;
+              xData.push((sample.timestamp - windowEndMs) / 1000);
+              yData.push(signalData.sensorReading);
+            }
+          } else {
+            let currentBinStart =
+              Math.floor(history[0].timestamp / resolution) * resolution;
+            let currentSum = 0;
+            let currentCount = 0;
+
+            for (const sample of history) {
+              const signalData = sample.data[signal.signalName];
+              if (signalData === undefined) continue;
+
+              const sampleBin =
+                Math.floor(sample.timestamp / resolution) * resolution;
+
+              if (sampleBin === currentBinStart) {
+                currentSum += signalData.sensorReading;
+                currentCount++;
+              } else {
+                if (currentCount > 0) {
+                  xData.push((currentBinStart - windowEndMs) / 1000);
+                  yData.push(currentSum / currentCount);
+                }
+                currentBinStart = sampleBin;
+                currentSum = signalData.sensorReading;
+                currentCount = 1;
               }
-
-              // Move to new bin
-              currentBinStart = sampleBin;
-              currentSum = signalData.sensorReading;
-              currentCount = 1;
             }
-          }
 
-          // Finalize last bin
-          if (currentCount > 0) {
-            const avg = currentSum / currentCount;
-            const x = (currentBinStart - windowEndMs) / 1000;
-            xData.push(x);
-            yData.push(avg);
+            if (currentCount > 0) {
+              xData.push((currentBinStart - windowEndMs) / 1000);
+              yData.push(currentSum / currentCount);
+            }
           }
         }
 

pecan/src/pages/Dashboard.tsx

@@ -863,6 +863,9 @@ function Dashboard() {
               <label className="text-gray-300 text-sm">
                 Time Window (seconds, max 120):
               </label>
+              {plotTimeWindow > 30000 && (
+                <p className="text-yellow-400 text-xs">Downsampling to 100ms bins (window &gt; 30s)</p>
+              )}
               <input
                 type="number"
                 min="1"