Correctly handle command changes from no-coordinate item to coordinate item

src/MissionManager/SimpleMissionItem.cc

@@ -743,6 +743,10 @@ void SimpleMissionItem::_setDefaultsForCommand(void)
         // No need to carry across previous lat/lon
         _missionItem._param5Fact.setRawValue(0);
         _missionItem._param6Fact.setRawValue(0);
+    } else if ((specifiesCoordinate() || isStandaloneCoordinate()) && _missionItem._param5Fact.rawValue().toDouble() == 0 && _missionItem._param6Fact.rawValue().toDouble() == 0) {
+        // We switched from a command without a coordinate to a command with a coordinate. Use the hint.
+        _missionItem._param5Fact.setRawValue(_mapCenterHint.latitude());
+        _missionItem._param6Fact.setRawValue(_mapCenterHint.longitude());
     }
 
     // Set global defaults first, then if there are param defaults they will get reset

src/MissionManager/SimpleMissionItem.h

@@ -49,6 +49,11 @@ public:
     Q_PROPERTY(QmlObjectListModel*  textFieldFacts  READ textFieldFacts CONSTANT)
     Q_PROPERTY(QmlObjectListModel*  nanFacts        READ nanFacts       CONSTANT)
 
+    /// This should be called before changing the command. It is needed if the command changes
+    /// from an item which does not include a coordinate to an item which requires a coordinate.
+    /// It uses this value to set that new coordinate.
+    Q_INVOKABLE void setMapCenterHintForCommandChange(QGeoCoordinate mapCenter) { _mapCenterHint = mapCenter; };
+
     /// Scans the loaded items for additional section settings
     ///     @param visualItems List of all visual items
     ///     @param scanIndex Index to start scanning from
@@ -162,6 +167,7 @@ private:
     bool            _rawEdit;
     bool            _dirty;
     bool            _ignoreDirtyChangeSignals;
+    QGeoCoordinate  _mapCenterHint;
 
     SpeedSection*   _speedSection;
     CameraSection* _cameraSection;

src/PlanView/MissionItemEditor.qml

@@ -204,7 +204,8 @@ Rectangle {
             id: commandDialog
 
             MissionCommandDialog {
-                missionItem: _root.missionItem
+                missionItem:    _root.missionItem
+                map:            _root.map
             }
         }
 

src/QmlControls/MissionCommandDialog.qml

@@ -20,6 +20,7 @@ QGCViewDialog {
     id: root
 
     property var missionItem
+    property var map
 
     property var _vehicle: QGroundControl.multiVehicleManager.activeVehicle
 
@@ -96,6 +97,7 @@ QGCViewDialog {
             MouseArea {
                 anchors.fill:   parent
                 onClicked: {
+                        missionItem.setMapCenterHintForCommandChange(map.center)
                     missionItem.command = mavCmdInfo.command
                     root.reject()
                 }