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, 10 insertions, 8 deletions

diff --git a/grapher/Graph.cxx b/grapher/Graph.cxx
index 4b5b8eb6..55ffcdf2 100644
--- a/grapher/Graph.cxx
+++ b/grapher/Graph.cxx
@@ -13,7 +13,8 @@ namespace systemtap
     : _width(600), _height(200), _graphX(0), _graphY(0),
       _graphWidth(580), _graphHeight(180),
       _lineWidth(2), _autoScaling(true), _autoScrolling(true),
-      _zoomFactor(1.0), _playButton(new CairoPlayButton),
+      _zoomFactor(1.0), _xOffset(20.0), _yOffset(0.0),
+      _playButton(new CairoPlayButton),
       _left(0), _right(1), _top(5.0), _bottom(0.0)
   {
     setOrigin(x, y);
@@ -80,7 +81,7 @@ namespace systemtap
     cr->save();
     double horizScale
         = _zoomFactor * _graphWidth / static_cast<double>(_right - _left);
-    cr->translate(20.0, 0.0);
+    cr->translate(_xOffset, _yOffset);
     cr->set_line_width(_lineWidth);
 
     for (DatasetList::iterator itr = _datasets.begin(), e = _datasets.end();
@@ -134,9 +135,9 @@ namespace systemtap
     cr->select_font_face("Sans", Cairo::FONT_SLANT_NORMAL,
                          Cairo::FONT_WEIGHT_NORMAL);
     cr->set_font_size(10.0);
-    cr->move_to(20.0, 0.0);
-    cr->line_to(20.0, _height);
-    cr->move_to(20.0, _graphHeight);
+    cr->move_to(_xOffset, _yOffset);
+    cr->line_to(_xOffset, _height);
+    cr->move_to(_xOffset, _graphHeight);
     cr->line_to(_graphWidth, _graphHeight);
     cr->stroke();
     std::valarray<double> dash(1);
@@ -145,8 +146,8 @@ namespace systemtap
     double prevTextAdvance = 0;
     for (int64_t tickVal = startTime; tickVal <= _right; tickVal += majorUnit)
       {
-        double x = (tickVal - _left) * horizScale + 20.0;
-        cr->move_to(x, 0.0);
+        double x = (tickVal - _left) * horizScale + _xOffset;
+        cr->move_to(x, _yOffset);
         cr->line_to(x, _graphHeight);
         std::ostringstream stream;
         stream << tickVal;
@@ -201,6 +202,7 @@ namespace systemtap
 
   int64_t Graph::getTimeAtPoint(double x)
   {
-    return _left + (_right - _left) * ((x - 20.0)/(_zoomFactor * _graphWidth));
+    return (_left
+            + (_right - _left) * ((x - _xOffset)/(_zoomFactor * _graphWidth)));
   }
 }