Make the hover text conform to data displayed.

Start of code to be more selective about the association between the
hover text and the underling graph. Also, show the data set name in hover text.

* grapher/GraphStyle.hxx (dataIndexAtPoint): New virtual function.
* grapher/GraphStyle.cxx (dataIndexAtPoint): Implementation for bar graphs
* grapher/GraphWidget.cxx (onHoverTimeout): Use dataIndexAtPoint.

1 files changed, 26 insertions, 0 deletions

diff --git a/grapher/GraphStyle.cxx b/grapher/GraphStyle.cxx
index 887ed55f..55fc73f4 100644
--- a/grapher/GraphStyle.cxx
+++ b/grapher/GraphStyle.cxx
@@ -8,6 +8,9 @@ namespace systemtap
   using namespace std;
   using namespace tr1;
 
+  typedef pair<GraphDataBase::TimeList::iterator,
+               GraphDataBase::TimeList::iterator>  TimeListPair;
+
   GraphStyleBar GraphStyleBar::instance;
   
   void GraphStyleBar::draw(std::tr1::shared_ptr<GraphDataBase> graphData,
@@ -41,6 +44,29 @@ namespace systemtap
       }
   }
 
+  ssize_t GraphStyleBar::dataIndexAtPoint(double x, double y,
+                                          shared_ptr<GraphDataBase> graphData,
+                                          shared_ptr<Graph> graph)
+  {
+    shared_ptr<GraphData<double> > realData
+      = dynamic_pointer_cast<GraphData<double> >(graphData);
+    if (!realData)
+      return -1;
+    int64_t left, right;
+    double top, bottom;
+    graph->getExtents(left, right, top, bottom);
+    double t = graph->getTimeAtPoint(x);
+    TimeListPair range
+      = equal_range(graphData->times.begin(), graphData->times.end(), t);
+    size_t dataIndex = distance(graphData->times.begin(), range.first);
+    double val = realData->data[dataIndex];
+    double ycoord = val * graph->_graphHeight / graphData->scale;
+    if (y >= graph->_yOffset + graph->_graphHeight - ycoord)
+      return static_cast<ssize_t>(dataIndex);
+    else
+      return -1;
+  }
+  
   GraphStyleDot GraphStyleDot::instance;
   
   void GraphStyleDot::draw(std::tr1::shared_ptr<GraphDataBase> graphData,