return an estimated fix from getBoatPositions if there is no real fix in an interval

java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/server/SailingServiceImpl.java

@@ -115,6 +115,7 @@ import com.sap.sailing.domain.tracking.TrackedRace;
 import com.sap.sailing.domain.tracking.Wind;
 import com.sap.sailing.domain.tracking.WindTrack;
 import com.sap.sailing.domain.tracking.WindWithConfidence;
+import com.sap.sailing.domain.tracking.impl.GPSFixMovingImpl;
 import com.sap.sailing.domain.tracking.impl.TrackedRaceImpl;
 import com.sap.sailing.domain.tracking.impl.WindImpl;
 import com.sap.sailing.domain.tractracadapter.DomainFactory;
@@ -1235,6 +1236,12 @@ public class SailingServiceImpl extends RemoteServiceServlet implements SailingS
                     } finally {
                         track.unlockAfterRead();
                     }
+                    if (fixes.isEmpty()) {
+                        // then there was no (smoothened) fix between fromTimePoint and toTimePointExcluding; estimate...
+                        TimePoint middle = new MillisecondsTimePoint((toTimePointExcluding.asMillis()+fromTimePoint.asMillis())/2);
+                        fixes.add(new GPSFixMovingImpl(track.getEstimatedPosition(middle, extrapolate), middle,
+                                        track.getEstimatedSpeed(middle)));
+                    }
                     Iterator<GPSFixMoving> fixIter = fixes.iterator();
                     if (fixIter.hasNext()) {
                         final WindSource windSource = new WindSourceImpl(WindSourceType.COMBINED);

java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/shared/racemap/RaceMap.java

@@ -457,7 +457,7 @@ public class RaceMap extends AbsolutePanel implements TimeListener, CompetitorSe
      */
     protected Triple<Map<CompetitorDTO, Date>, Map<CompetitorDTO, Date>, Map<CompetitorDTO, Boolean>> computeFromAndTo(
             Date upTo, Iterable<CompetitorDTO> competitorsToShow) {
-        Date tailstart = new Date(upTo.getTime() - settings.getTailLengthInMilliseconds());
+        Date tailstart = new Date(upTo.getTime() - settings.getEffectiveTailLengthInMilliseconds());
         Map<CompetitorDTO, Date> from = new HashMap<CompetitorDTO, Date>();
         Map<CompetitorDTO, Date> to = new HashMap<CompetitorDTO, Date>();
         Map<CompetitorDTO, Boolean> overlapWithKnownFixes = new HashMap<CompetitorDTO, Boolean>();
@@ -589,7 +589,7 @@ public class RaceMap extends AbsolutePanel implements TimeListener, CompetitorSe
 
     protected void showBoatsOnMap(final Date date, final Iterable<CompetitorDTO> competitorsToShow) {
         if (map != null) {
-            Date tailsFromTime = settings.isShowTails() ? new Date(date.getTime() - settings.getTailLengthInMilliseconds()) : new Date(date.getTime());
+            Date tailsFromTime = new Date(date.getTime() - settings.getEffectiveTailLengthInMilliseconds());
             Date tailsToTime = new Date(date.getTime());
             Set<CompetitorDTO> competitorDTOsOfUnusedTails = new HashSet<CompetitorDTO>(tails.keySet());
             Set<CompetitorDTO> competitorDTOsOfUnusedBoatCanvases = new HashSet<CompetitorDTO>(boatCanvasOverlays.keySet());
@@ -1556,7 +1556,7 @@ public class RaceMap extends AbsolutePanel implements TimeListener, CompetitorSe
             settings.setMaxVisibleCompetitorsCount(newSettings.getMaxVisibleCompetitorsCount());
             requiredRedraw = true;
         }
-        if(requiredRedraw) {
+        if (requiredRedraw) {
             redraw();
         }
     }

java/com.sap.sailing.gwt.ui/src/main/java/com/sap/sailing/gwt/ui/shared/racemap/RaceMapSettings.java

@@ -31,7 +31,18 @@ public class RaceMapSettings {
         this.zoomSettings = new RaceMapZoomSettings();
         this.helpLinesSettings = new RaceMapHelpLinesSettings();
     }
+    
+    /**
+     * @return 0 if {@link #isShowTails()} returns <code>false</code>; {@link #getTailLengthInMilliseconds()} otherwise
+     */
+    public long getEffectiveTailLengthInMilliseconds() {
+        return isShowTails() ? getTailLengthInMilliseconds() : 0;
+    }
 
+    /**
+     * The tail length as set in the dialog; feeds into {@link #getEffectiveTailLengthInMilliseconds()}, but only if
+     * {@link #isShowTails()} is <code>true</code>.
+     */
     public long getTailLengthInMilliseconds() {
         return tailLengthInMilliseconds;
     }