Use QmlObjectListModel::begin/endReset to keep Qt from blowing it's brains out with too many updates

src/MissionManager/MissionController.cc

@@ -1110,9 +1110,14 @@ void MissionController::_recalcWaypointLines(void)
     qCDebug(MissionControllerLog) << "_recalcWaypointLines homePositionValid" << homePositionValid;
 
     CoordVectHashTable old_table = _linesTable;
+
     _linesTable.clear();
-    _waypointLines.clear();
     _waypointPath.clear();
+
+    _waypointLines.beginReset();
+    _directionArrows.beginReset();
+
+    _waypointLines.clear();
     _directionArrows.clear();
 
     bool linkEndToHome;
@@ -1150,7 +1155,10 @@ void MissionController::_recalcWaypointLines(void)
 
                 lastSegmentVisualItemPair =  VisualItemPair(lastCoordinateItem, item);
                 if (!_flyView || addDirectionArrow) {
-                    _directionArrows.append(_addWaypointLineSegment(old_table, lastSegmentVisualItemPair));
+                    CoordinateVector* coordVector = _addWaypointLineSegment(old_table, lastSegmentVisualItemPair);
+                    if (addDirectionArrow) {
+                        _directionArrows.append(coordVector);
+                    }
                 }
             }
             firstCoordinateItem = false;
@@ -1205,6 +1213,9 @@ void MissionController::_recalcWaypointLines(void)
         _waypointLines.swapObjectList(objs);
     }
 
+    _waypointLines.endReset();
+    _directionArrows.endReset();
+
     // Anything left in the old table is an obsolete line object that can go
     qDeleteAll(old_table);
 
@@ -1219,6 +1230,7 @@ void MissionController::_recalcWaypointLines(void)
     }
 
     emit waypointLinesChanged();
+    emit directionArrowsChanged();
     emit waypointPathChanged();
 }
 

src/MissionManager/MissionController.h

@@ -70,7 +70,7 @@ public:
     Q_PROPERTY(QmlObjectListModel*  visualItems             READ visualItems                NOTIFY visualItemsChanged)
     Q_PROPERTY(QmlObjectListModel*  waypointLines           READ waypointLines              NOTIFY waypointLinesChanged)        ///< Used by Plan view only for interactive editing
     Q_PROPERTY(QVariantList         waypointPath            READ waypointPath               NOTIFY waypointPathChanged)         ///< Used by Fly view only for static display
-    Q_PROPERTY(QmlObjectListModel*  directionArrows         READ directionArrows            CONSTANT)
+    Q_PROPERTY(QmlObjectListModel*  directionArrows         READ directionArrows            NOTIFY directionArrowsChanged)
     Q_PROPERTY(QStringList          complexMissionItemNames READ complexMissionItemNames    NOTIFY complexMissionItemNamesChanged)
     Q_PROPERTY(QGeoCoordinate       plannedHomePosition     READ plannedHomePosition        NOTIFY plannedHomePositionChanged)
 
@@ -207,6 +207,7 @@ public:
 signals:
     void visualItemsChanged             (void);
     void waypointLinesChanged           (void);
+    void directionArrowsChanged         (void);
     void waypointPathChanged            (void);
     void newItemsFromVehicle            (void);
     void missionDistanceChanged         (double missionDistance);