navigator: stop capturing images on mission exit

When a mission starts capturing images using the
MAV_CMD_IMAGE_START_CAPTURE command, it should also stop it again, in
case it is stopped early, e.g. with RTL.

src/modules/navigator/mission.cpp

@@ -173,6 +173,7 @@ Mission::on_inactivation()
 	cmd.param3 = 1.0f;
 	_navigator->publish_vehicle_cmd(&cmd);
 
+	_navigator->stop_capturing_images();
 	_navigator->release_gimbal_control();
 
 	if (_navigator->get_precland()->is_activated()) {

src/modules/navigator/navigator.h

@@ -329,6 +329,7 @@ public:
 	void release_gimbal_control();
 
 	void 		calculate_breaking_stop(double &lat, double &lon, float &yaw);
+	void        	stop_capturing_images();
 
 private:
 
@@ -422,6 +423,9 @@ private:
 
 	traffic_buffer_s _traffic_buffer{};
 
+	bool _is_capturing_images{false}; // keep track if we need to stop capturing images
+
+
 	// update subscriptions
 	void params_update();
 

src/modules/navigator/navigator_main.cpp

@@ -1499,7 +1499,20 @@ void Navigator::publish_vehicle_cmd(vehicle_command_s *vcmd)
 	// sent to the mavlink links to other components.
 	switch (vcmd->command) {
 	case NAV_CMD_IMAGE_START_CAPTURE:
+
+		// We are only capturing multiple if param3 is 0 or > 1.
+		if (static_cast<int>(vcmd->param3) != 1) {
+			_is_capturing_images = true;
+		}
+
+		vcmd->target_component = 100; // MAV_COMP_ID_CAMERA
+		break;
+
 	case NAV_CMD_IMAGE_STOP_CAPTURE:
+		_is_capturing_images = false;
+		vcmd->target_component = 100; // MAV_COMP_ID_CAMERA
+		break;
+
 	case NAV_CMD_VIDEO_START_CAPTURE:
 	case NAV_CMD_VIDEO_STOP_CAPTURE:
 		vcmd->target_component = 100; // MAV_COMP_ID_CAMERA
@@ -1552,6 +1565,20 @@ void Navigator::release_gimbal_control()
 	publish_vehicle_cmd(&vcmd);
 }
 
+
+void
+Navigator::stop_capturing_images()
+{
+	if (_is_capturing_images) {
+		vehicle_command_s vcmd = {};
+		vcmd.command = NAV_CMD_IMAGE_STOP_CAPTURE;
+		vcmd.param1 = 0.0f;
+		publish_vehicle_cmd(&vcmd);
+
+		// _is_capturing_images is reset inside publish_vehicle_cmd.
+	}
+}
+
 bool Navigator::geofence_allows_position(const vehicle_global_position_s &pos)
 {
 	if ((_geofence.getGeofenceAction() != geofence_result_s::GF_ACTION_NONE) &&