Hover text for event-style graphs

Don't draw the data value for an event; only display it in hover text.

* grapher/Graph.hxx (window2GraphCoords): new function
* grapher/Graph.cxx (window2GraphCoords): ditto
* grapher/GraphStyle.cxx (GraphStyleEvent::dataIndexAtPoint): new
  function implementation.

1 files changed, 35 insertions, 13 deletions

diff --git a/grapher/GraphStyle.cxx b/grapher/GraphStyle.cxx
index 55fc73f4..cf3855e3 100644
--- a/grapher/GraphStyle.cxx
+++ b/grapher/GraphStyle.cxx
@@ -132,20 +132,9 @@ namespace systemtap
          ditr != de;
          ++ditr)
       {
-        size_t dataIndex = ditr - graphData->times.begin();
+        // size_t dataIndex = ditr - graphData->times.begin();
         double eventHeight = graph->_graphHeight * (graphData->scale / 100.0);
         cr->save();
-        cr->select_font_face("Sans", Cairo::FONT_SLANT_NORMAL,
-                             Cairo::FONT_WEIGHT_NORMAL);
-        cr->set_font_size(12.0);
-        cr->set_source_rgba(graphData->color[0], graphData->color[1],
-                            graphData->color[2], 1.0);
-        cr->save();
-        cr->scale(1.0, -1.0);
-        cr->move_to((*ditr - left) * horizScale,
-                    -eventHeight - 3.0 * graph->_lineWidth - 2.0);
-        cr->show_text(stringData->data[dataIndex]);
-        cr->restore();
         cr->rectangle((*ditr - left) * horizScale - 1.5 * graph->_lineWidth,
                       eventHeight - 1.5 * graph->_lineWidth,
                       3.0 * graph->_lineWidth, 3.0 * graph->_lineWidth);
@@ -153,5 +142,38 @@ namespace systemtap
         cr->restore();
       }
   }
-  
+
+  ssize_t GraphStyleEvent::dataIndexAtPoint(double x, double y,
+                                            shared_ptr<GraphDataBase> graphData,
+                                            shared_ptr<Graph> graph)
+  {
+    shared_ptr<GraphData<string> > stringData
+      = dynamic_pointer_cast<GraphData<string> >(graphData);
+    if (!stringData)
+      return -1;
+    int64_t left, right;
+    double top, bottom;
+    graph->getExtents(left, right, top, bottom);
+    double horizScale = (graph->_zoomFactor * graph->_graphWidth
+                         / static_cast<double>(right - left));
+    double eventHeight = graph->_graphHeight * (graphData->scale / 100.0);
+    GraphDataBase::TimeList::iterator lower
+      = lower_bound(graphData->times.begin(), graphData->times.end(), left);
+    GraphDataBase::TimeList::iterator upper
+      = upper_bound(graphData->times.begin(), graphData->times.end(), right);
+    // easier to transform x,y into graph coordinates
+    double xgraph, ygraph;
+    graph->window2GraphCoords(x, y, xgraph, ygraph);
+    double yrect = eventHeight - 1.5 * graph->_lineWidth;
+    for (GraphDataBase::TimeList::iterator ditr = lower, de = upper;
+         ditr != de;
+         ++ditr)
+      {
+        double xrect = (*ditr - left) * horizScale - 1.5 * graph->_lineWidth;
+        if (xrect <= xgraph && xgraph < xrect + 3.0 * graph->_lineWidth
+            && yrect <= ygraph && ygraph < yrect + 3.0 * graph->_lineWidth)
+          return static_cast<ssize_t>(distance(lower, ditr));
+      }
+    return -1;
+  }
 }