Resolve issue of computing actual log rate for spectrum chart in case of data gaps in log file (betaflight#762)

* added compute of unlogged time by handling log resumd events

* added getActualLoggedTime function in FlightLog

* improve getMinTime, getMaxTime functions in FlightLog

* Improved actual log rate computing in spectrum chart

* code style improvement

* code style improvement

Author: demvlad

src/flightlog.js

@@ -31,7 +31,7 @@ import {
 export function FlightLog(logData) {
   let ADDITIONAL_COMPUTED_FIELD_COUNT = 15 /** attitude + PID_SUM + PID_ERROR + RCCOMMAND_SCALED **/,
     that = this,
-    logIndex = false,
+    logIndex = 0,
     logIndexes = new FlightLogIndex(logData),
     parser = new FlightLogParser(logData),
     iframeDirectory,
@@ -117,20 +117,21 @@ export function FlightLog(logData) {
    * Get the earliest time seen in the log of the given index (in microseconds), or leave off the logIndex
    * argument to fetch details for the current log.
    */
-  this.getMinTime = function (logIndex) {
-    return getRawStats(logIndex).frame["I"].field[
-      FlightLogParser.prototype.FLIGHT_LOG_FIELD_INDEX_TIME
-    ].min;
+  this.getMinTime = function () {
+    return logIndexes.getIntraframeDirectory(logIndex).minTime;
   };
 
   /**
    * Get the latest time seen in the log of the given index (in microseconds), or leave off the logIndex
    * argument to fetch details for the current log.
    */
-  this.getMaxTime = function (logIndex) {
-    return getRawStats(logIndex).frame["I"].field[
-      FlightLogParser.prototype.FLIGHT_LOG_FIELD_INDEX_TIME
-    ].max;
+  this.getMaxTime = function () {
+    return logIndexes.getIntraframeDirectory(logIndex).maxTime;
+  };
+  
+  this.getActualLoggedTime = function () {
+    const directory = logIndexes.getIntraframeDirectory(logIndex);
+    return directory.maxTime - directory.minTime - directory.unLoggedTime;
   };
 
   /**

src/flightlog_index.js

@@ -56,6 +56,7 @@ export function FlightLogIndex(logData) {
           hasEvent: [],
           minTime: false,
           maxTime: false,
+          unLoggedTime: 0,
         },
         imu = new IMU(),
         gyroADC,
@@ -125,7 +126,8 @@ export function FlightLogIndex(logData) {
         if (magADC[0] === undefined) {
           magADC = false;
         }
-
+        
+        let frameTime;
         parser.onFrameReady = function (
           frameValid,
           frame,
@@ -140,9 +142,7 @@ export function FlightLogIndex(logData) {
           switch (frameType) {
             case "P":
             case "I":
-              var frameTime =
-                frame[FlightLogParser.prototype.FLIGHT_LOG_FIELD_INDEX_TIME];
-
+              frameTime = frame[FlightLogParser.prototype.FLIGHT_LOG_FIELD_INDEX_TIME];
               if (intraIndex.minTime === false) {
                 intraIndex.minTime = frameTime;
               }
@@ -225,6 +225,13 @@ export function FlightLogIndex(logData) {
               if (frame.event == FlightLogEvent.LOG_END) {
                 sawEndMarker = true;
               }
+
+              if (frame.event == FlightLogEvent.LOGGING_RESUME) {
+                if (frameTime) {
+                  intraIndex.unLoggedTime += frame.data.currentTime - frameTime;
+                }
+              }
+
               break;
             case "S":
               lastSlow = frame.slice(0);

src/graph_spectrum_calc.js

@@ -50,12 +50,10 @@ GraphSpectrumCalc.initialize = function(flightLog, sysConfig) {
   }
   this._BetaflightRate = this._blackBoxRate;
 
-  const minTime = this._flightLog.getMinTime(),
-      maxTime = this._flightLog.getMaxTime(),
-      timeRange = maxTime - minTime;
+  const actualLoggedTime = this._flightLog.getActualLoggedTime(),
+        length = flightLog.getCurrentLogRowsCount();
 
-  const length = flightLog.getCurrentLogRowsCount();
-  this._actualeRate = 1e6 * length / timeRange;
+  this._actualeRate = 1e6 * length / actualLoggedTime;
   if (Math.abs(this._BetaflightRate - this._actualeRate) / this._actualeRate > WARNING_RATE_DIFFERENCE)
       this._blackBoxRate = Math.round(this._actualeRate);