Bump to C++14.

Fixed topic containing the transport.
Improved load balancing to image transport for throttled cameras.
Will now update new subscriptions as quickly as possible (as long as no scheduled camera is currently updated).
Subscription moved to background thread to reduce load on UI thread.

CMakeLists.txt

@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.10)
 project(qml_ros_plugin)
-set(CMAKE_CXX_STANDARD 11)
+set(CMAKE_CXX_STANDARD 14)
 
 add_definitions(-Wall -Wextra)
 

include/qml_ros_plugin/image_transport_manager.h

@@ -33,6 +33,7 @@ class ImageTransportManager
 
   struct SubscriptionManager;
   class Subscription;
+  class LoadBalancer;
 public:
 
   static ImageTransportManager &getInstance();
@@ -64,12 +65,8 @@ class ImageTransportManager
              int throttle_interval = 0 );
 
 private:
-  int getLoadBalancedTimeout( int desired_throttle_interval );
-
   std::map<std::string, std::shared_ptr<SubscriptionManager>> subscriptions_;
-  std::vector<long> timeouts_;
-  std::mutex load_balancer_mutex_;
-  bool load_balancing_enabled_ = true;
+  std::unique_ptr<LoadBalancer> load_balancer_;
 
   friend class ImageTransportSubscriptionHandle;
 };
@@ -80,11 +77,11 @@ class ImageTransportSubscriptionHandle
 
   ~ImageTransportSubscriptionHandle();
 
-  //! The interval the subscription waits between receiving images.
+  //! The interval in ms the subscription waits between receiving images.
   int throttleInterval() const { return throttle_interval; }
 
-  //! Set the interval the subscription may wait between images.
-  //! The images may still arrive at a higher rate if other subscriptions_ request it.
+  //! Set the interval in ms the subscription may wait between images.
+  //! The images may still arrive at a higher rate if other subscriptions request it.
   void updateThrottleInterval( int interval );
 
   std::string getTopic();