From Jean-Sebastien Guay, "For a long time now I've wanted to be able to add custom values into the stats handler's graph. Here is my proposal of how I'd do this. It's surely not perfect and I'm open to suggestions, but I've already made more changes than I wanted to in order to be able to implement this...

The user calls statsHandler->addUserStatsLine() providing:

- the label they want for that line in the graph
- the text and bar colors they want in the graph
- the stats names they want queried (one for time taken, one for begin and one for end time) and a few settings for how these will be displayed.

Then all they have to do is call viewer->getViewerStats()->setAttribute(framenumber, name, value) for their three attributes each frame and they'll have their stats in the graph.

They can also give only a time taken attribute (or some other numerical value they want printed, which can be averaged or not), or only begin+end attributes, and the graph will accordingly display only the (average or not) numerical value or only the bars.

Along the way I cleaned up the existing code a bit:

* Each time the setUpScene() or createCameraTimeStats() methods added a line to the graph, they did pretty much the same thing, so I moved that into a separate method called createTimeStatsLine() which is called by setUpScene() and createCameraTimeStats().

* I moved the font, characterSize, startBlocks and leftPos variables to member variables, since they were being passed around everywhere but were set only once at the beginning.

* The geode on which stats lines are added is also kept in a member variable, and createCameraTimeStats() adds the per-camera lines to this geode instead of returning a new Group with a new Geode. This further reduces the number of variables the createCameraTimeStats() method needs as input.

"

include/osgViewer/ViewerEventHandlers

@@ -108,7 +108,15 @@ class OSGVIEWER_EXPORT StatsHandler : public osgGA::GUIEventHandler
         /** Get the keyboard and mouse usage of this manipulator.*/
         virtual void getUsage(osg::ApplicationUsage& usage) const;
 
-    protected:
+        /** This allows the user to register additional stats lines that will 
+            be added to the graph. The stats for these will be gotten from the
+            viewer (viewer->getViewerStats()). */
+        void addUserStatsLine(const std::string& label, const osg::Vec4& textColor, const osg::Vec4& barColor, 
+                              const std::string& timeTakenName, float multiplier, bool average, bool averageInInverseSpace, 
+                              const std::string& beginTimeName, const std::string& endTimeName, float maxValue);
+        void removeUserStatsLine(const std::string& label);
+
+protected:
 
         void setUpHUDCamera(osgViewer::ViewerBase* viewer);
 
@@ -120,7 +128,12 @@ class OSGVIEWER_EXPORT StatsHandler : public osgGA::GUIEventHandler
 
         osg::Geometry* createTick(const osg::Vec3& pos, float height, const osg::Vec4& colour, unsigned int numTicks);
 
-        osg::Node* createCameraTimeStats(const std::string& font, osg::Vec3& pos, float startBlocks, bool acquireGPUStats, float characterSize, osg::Stats* viewerStats, osg::Camera* camera);
+        void createTimeStatsLine(const std::string& lineLabel, osg::Vec3 pos, 
+                                 const osg::Vec4& textColor, const osg::Vec4& barColor, osg::Stats* viewerStats, osg::Stats* stats, 
+                                 const std::string& timeTakenName, float multiplier, bool average, bool averageInInverseSpace, 
+                                 const std::string& beginTimeName, const std::string& endTimeName);
+
+        void createCameraTimeStats(osg::Vec3& pos, bool acquireGPUStats, osg::Stats* viewerStats, osg::Camera* camera);
 
         void setUpScene(osgViewer::ViewerBase* viewer);
 
@@ -137,6 +150,8 @@ class OSGVIEWER_EXPORT StatsHandler : public osgGA::GUIEventHandler
 
         osg::ref_ptr<osg::Switch>           _switch;
 
+        osg::ref_ptr<osg::Geode>            _statsGeode;
+
         ViewerBase::ThreadingModel          _threadingModel;
         osg::ref_ptr<osgText::Text>         _threadingModelText;
 
@@ -150,6 +165,36 @@ class OSGVIEWER_EXPORT StatsHandler : public osgGA::GUIEventHandler
         float                               _statsWidth;
         float                               _statsHeight;
 
+        std::string                         _font;
+        float                               _startBlocks;
+        float                               _leftPos;
+        float                               _characterSize;
+
+        struct UserStatsLine
+        {
+            std::string label;
+            osg::Vec4 textColor;
+            osg::Vec4 barColor;
+            std::string timeTakenName;
+            float multiplier;
+            bool average;
+            bool averageInInverseSpace;
+            std::string beginTimeName;
+            std::string endTimeName;
+            float maxValue;
+
+            UserStatsLine(const std::string& label_, const osg::Vec4& textColor_, const osg::Vec4& barColor_, 
+                          const std::string& timeTakenName_, float multiplier_, bool average_, bool averageInInverseSpace_, 
+                          const std::string& beginTimeName_, const std::string& endTimeName_, float maxValue_)
+                : label(label_), textColor(textColor_), barColor(barColor_), 
+                  timeTakenName(timeTakenName_), multiplier(multiplier_), average(average_), averageInInverseSpace(averageInInverseSpace_), 
+                  beginTimeName(beginTimeName_), endTimeName(endTimeName_), maxValue(maxValue_)
+            {
+            }
+        };
+
+        typedef std::vector<UserStatsLine>  UserStatsLines;
+        UserStatsLines                      _userStatsLines;
 
 };