Resolved issues of using power at 2 values

Author: demvlad

src/graph_spectrum_calc.js

@@ -117,13 +117,14 @@ GraphSpectrumCalc.dataLoadPSD = function(analyserZoomY) {
   const multiplier = Math.floor(1 / analyserZoomY); // 0. ... 10
   let pointsPerSegment = 2 ** (8 + multiplier); //256, 512, 1024 ...
 
-  // Use power 2 fft size what is not bigger flightSamples.samples.length
+  let overlapCount;
   if (pointsPerSegment > flightSamples.samples.length) {
-      pointsPerSegment = this.getNearPower2Value(flightSamples.samples.length);
+      pointsPerSegment = flightSamples.samples.length;  // Use actual sample length. It will transform to power at 2 value inside the _psd() - fft_segmented
+      overlapCount = 0;
+  } else {
+    overlapCount = pointsPerSegment / 2;
   }
 
-  const overlapCount = pointsPerSegment / 2;
-
   const psd =  this._psd(flightSamples.samples, pointsPerSegment, overlapCount);
 
   const psdData = {

src/graph_spectrum_plot.js

@@ -350,7 +350,10 @@ GraphSpectrumPlot._drawPowerSpectralDensityGraph = function (canvasCtx) {
   // Allign y axis range by 10db
   const dbStep = 10;
   const minY = Math.floor(this._fftData.minimum / dbStep) * dbStep;
-  const maxY = (Math.floor(this._fftData.maximum / dbStep) + 1) * dbStep;
+  let maxY = (Math.floor(this._fftData.maximum / dbStep) + 1) * dbStep;
+  if (minY == maxY) {
+    maxY = minY + 1;  // prevent divide by zero
+  }
   const ticksCount = (maxY - minY) / dbStep;
   const scaleY = HEIGHT / (maxY - minY);
   //Store vsRange for _drawMousePosition