Added importSpectrumFromCSV method to FlightLogAnalyser

Author: demvlad

src/graph_spectrum.js

@@ -289,7 +289,35 @@ export function FlightLogAnalyser(flightLog, canvas, analyserCanvas) {
     this.exportSpectrumToCSV = function(onSuccess, options) {
       SpectrumExporter(fftData, options).dump(onSuccess);
     };
+    this.importSpectrumFromCSV = function(files) {
+      const reader = new FileReader();
+      reader.onload = function (e) {
+        try {
+          const stringRows = e.target.result.split("\n");
+
+          const header = stringRows[0].split(",");
+          if (header.length != 2 || header[0] != "freq" || header[1] != "value") {
+            throw new SyntaxError("Wrong spectrum CSV data format");
+          }
+
+          stringRows.shift();
+          const spectrumData = stringRows.map( function(row) {
+            const data = row.split(",");
+            return {
+              freq: parseFloat(data[0]),
+              value: parseFloat(data[1]),
+            };
+          });
+          GraphSpectrumPlot.setImportedSpectrumData(spectrumData);
+        } catch (e) {
+          alert('Spectrum data import error: ' + e.message);
+          return;
+        }
+      }
+      reader.readAsText(files[0]);
+    }
+
   } catch (e) {
-    console.log(`Failed to create analyser... error:${e}`);
+    console.log(`Failed to create analyser... error: ${e}`);
   }
 }