grapher: scroll continuously with time

Don't scale graph based on how much data will fit. This didn't work
very well and resulted in distracting, weird scale changes. We now
assume that scripts output their time (x axis) in milliseconds.

* grapher/Graph.hxx (setCurrentTime): New function.
* grapher/Graph.cxx (Graph::draw): Assume a fixed default scale of 1
  pixel = 5 milliseconds and don't do any autoscaling.
* grapher/GraphWidget.cxx (GraphWidget constructor): Set global time
  base on startup.
  (on_expose_event): Don't search graphs for earliest time.
* grapher/GraphWidget.hxx (_timeBaseInitialized): delete
* grapher/Time.hxx: new file; interface to timeval.

1 files changed, 6 insertions, 49 deletions

diff --git a/grapher/Graph.cxx b/grapher/Graph.cxx
index dc808fa4..27b6a24f 100644
--- a/grapher/Graph.cxx
+++ b/grapher/Graph.cxx
@@ -19,7 +19,9 @@ using namespace std::tr1;
 
 GraphDataList GraphDataBase::graphData;
 sigc::signal<void> GraphDataBase::graphDataChanged;
-  
+
+int64_t Graph::_currentTime = 0;
+
 Graph::Graph(double x, double y)
   : _width(600), _height(200), _graphX(0), _graphY(0),
     _graphWidth(580), _graphHeight(180),
@@ -39,55 +41,10 @@ void Graph::draw(Cairo::RefPtr<Cairo::Context> cr)
     
   if (_autoScaling)
     {
-      // line separation
-      int linesPossible = (int)(_graphWidth / (_lineWidth + 2.0));
       // Find latest time.
-      int64_t latestTime = 0;
-      for (GraphDataList::iterator ditr = _datasets.begin(),
-             de = _datasets.end();
-           ditr != de;
-           ++ditr)
-        {
-          if (!(*ditr)->times.empty())
-            {
-              int64_t lastDataTime = (*ditr)->times.back();
-              if (lastDataTime > latestTime)
-                latestTime = lastDataTime;
-            }
-        }
-      int64_t minDiff = 0;
-      int64_t maxTotal = 0;
-      for (GraphDataList::iterator ditr = _datasets.begin(),
-             de = _datasets.end();
-           ditr != de;
-           ++ditr)
-        {
-          GraphDataBase::TimeList& gtimes = (*ditr)->times;
-          if (gtimes.size() <= 1)
-            continue;
-          double totalDiff = 0.0;
-          for (GraphDataBase::TimeList::reverse_iterator ritr = gtimes.rbegin(),
-                 re = gtimes.rend();
-               ritr + 1 != gtimes.rend();
-               ritr++)
-            {
-              int64_t timeDiff = *ritr - *(ritr + 1);
-              if (timeDiff < minDiff || (timeDiff != 0 && minDiff == 0))
-                minDiff = timeDiff;
-              if (minDiff != 0
-                  && ((totalDiff + timeDiff) / minDiff + 1) > linesPossible)
-                break;
-              totalDiff += timeDiff;
-            }
-          if (totalDiff > maxTotal)
-            maxTotal = totalDiff;
-        }
-      // Now we have a global scale.
-      _right = latestTime;
-      if (maxTotal != 0)
-        _left = latestTime - maxTotal;
-      else
-        _left = _right - 1;
+      _right =  _currentTime / 1000;
+      // Assume 1 pixel = 5 milliseconds
+      _left = _right - 5000;
     }
   cr->save();
   double horizScale