Update CompositeEvent.cs

Issue #390 Add another means to filter events by removing an event which is entirely enclosed by another event. This circumstance now arises due to the new way of using decibel thresholds.

src/AudioAnalysisTools/Events/Types/CompositeEvent.cs

@@ -343,6 +343,64 @@ public static SpectralEvent OverlapsEventInList(SpectralEvent anEvent, List<Spec
             return null;
         }
 
+        /// <summary>
+        /// Removes from a list of events, those events that are enclosed by another event in the list.
+        /// Returns a reduced list.
+        /// </summary>
+        public static List<EventCommon> RemoveEnclosedEvents(List<EventCommon> events)
+        {
+            if (events.Count < 2)
+            {
+                return events.Cast<EventCommon>().ToList();
+            }
+
+            for (int i = events.Count - 1; i >= 0; i--)
+            {
+                for (int j = i - 1; j >= 0; j--)
+                {
+                    var a = events[i] as SpectralEvent;
+                    var b = events[j] as SpectralEvent;
+
+                    (SpectralEvent evAi, SpectralEvent evBj) = EnclosedEvents(a, b);
+
+                    if (evAi != null && evBj == null)
+                    {
+                        events[j] = evAi;
+                        events.RemoveAt(i);
+                        break;
+                    }
+                    else
+                    if (evAi == null && evBj != null)
+                    {
+                        events[j] = evBj;
+                        events.RemoveAt(i);
+                        break;
+                    }
+                }
+            }
+
+            return events.Cast<EventCommon>().ToList();
+        }
+
+        public static (SpectralEvent EvAi, SpectralEvent EvBj) EnclosedEvents(SpectralEvent a, SpectralEvent b)
+        {
+            bool eventAEnclosedInTime = a.EventStartSeconds >= b.EventStartSeconds && a.EventEndSeconds <= b.EventEndSeconds;
+            bool eventAEnclosedInFreq = a.LowFrequencyHertz >= b.LowFrequencyHertz && a.HighFrequencyHertz <= b.HighFrequencyHertz;
+            if (eventAEnclosedInTime && eventAEnclosedInTime)
+            {
+                return (null, b);
+            }
+
+            bool eventBEnclosedInTime = a.EventStartSeconds <= b.EventStartSeconds && a.EventEndSeconds >= b.EventEndSeconds;
+            bool eventBEnclosedInFreq = a.LowFrequencyHertz <= b.LowFrequencyHertz && a.HighFrequencyHertz >= b.HighFrequencyHertz;
+            if (eventAEnclosedInTime && eventAEnclosedInTime)
+            {
+                return (a, null);
+            }
+
+            return (a, b);
+        }
+
         /*
         /// <summary>
         /// This method not currently called but is POTENTIALLY USEFUL.