option to display graph times relative to the start time

This avoids having humongous numbers displayed on the graphs' x
axis. Also, the dialog for adding a data set to a graph was cleaned
up.

* grapher/graph-dialog.glade: Add check box for display of relative
  time and a label for the data set list. Force the list of data sets
  to be larger.
* grapher/Graph.hxx (_timeBase): new member
* grapher/Graph.cxx (draw): Subtract _timeBase from displayed time
  value.
* grapher/GraphWidget.hxx (DataModelColumns): Add a column for a data
  set's title, which is optional at the moment.
* grapher/GraphWidget.hxx (_globalTimeBase, _timeBaseInitialized,
  _relativeTimesButton, _displayRelativeTimes): new members
* grapher/GraphWidget.hxx (GraphWidget): Hook up check button for
  displaying relative time.
  (on_expose_event): Determine base time if needed; set base time in
  graphs.
  (onDataDialogOpen): Insert graph data set's name (key) and title
  into the list of data sets.

1 files changed, 1 insertions, 0 deletions

diff --git a/grapher/Graph.hxx b/grapher/Graph.hxx
index 044a66d3..93e23deb 100644
--- a/grapher/Graph.hxx
+++ b/grapher/Graph.hxx
@@ -39,6 +39,7 @@ namespace systemtap
     double _xOffset;
     double _yOffset;
     std::tr1::shared_ptr<CairoPlayButton> _playButton;
+    int64_t _timeBase;
     DatasetList& getDatasets() { return _datasets; }
     int64_t getTimeAtPoint(double x);
     void window2GraphCoords(double x, double y, double& xgraph, double& ygraph);