UI Nits: LTMSidebar performance

Don't refresh CP, LTM or Histogram plots when dateRange property
is set, if the dateRange was previously plotted anyway. Will set
to stale if a ride is added or deleted too.

This means the replot of tabs is not performed when simply switching
between tabs. But will if the date range does change or a ride is
added or deleted meaning the aggregate needs to be re-calculated.

There is still one more performance improvement required;

1. get RideFileCache to have a cache of recent aggregations.
   Since (a) the same ranges will be called over and over by
   different charts when a season is selected and (b) there
   are only likely to be 20-30 seasons defined in total, so
   lets cache them instead of recalculating every time.

src/CriticalPowerWindow.cpp

@@ -34,7 +34,7 @@
 #include <QXmlSimpleReader>
 
 CriticalPowerWindow::CriticalPowerWindow(const QDir &home, MainWindow *parent, bool rangemode) :
-    GcWindow(parent), _dateRange("{00000000-0000-0000-0000-000000000001}"), home(home), mainWindow(parent), currentRide(NULL), rangemode(rangemode)
+    GcWindow(parent), _dateRange("{00000000-0000-0000-0000-000000000001}"), home(home), mainWindow(parent), currentRide(NULL), rangemode(rangemode), stale(true)
 {
     setInstanceName("Critical Power Window");
 
@@ -136,6 +136,9 @@ CriticalPowerWindow::CriticalPowerWindow(const QDir &home, MainWindow *parent, b
 void
 CriticalPowerWindow::newRideAdded(RideItem *here)
 {
+    // any plots we already have are now stale
+    stale = true;
+
     // mine just got Zapped, a new rideitem would not be my current item
     if (here == currentRide) currentRide = NULL;
 
@@ -375,8 +378,14 @@ CriticalPowerWindow::dateRangeChanged(DateRange dateRange)
 {
     if (!amVisible()) return;
 
+    if (dateRange.from == cfrom && dateRange.to == cto && !stale) return;
+
     cpintPlot->changeSeason(dateRange.from, dateRange.to);
     cpintPlot->calculate(currentRide);
+
+    cfrom = dateRange.from;
+    cto = dateRange.to;
+    stale = false;
 }
 
 void CriticalPowerWindow::seasonSelected(int iSeason)

src/CriticalPowerWindow.h

@@ -118,6 +118,8 @@ class CriticalPowerWindow : public GcWindow
 #endif
 
         bool rangemode;
+        QDate cfrom, cto;
+        bool stale;
 };
 
 #endif // _GC_CriticalPowerWindow_h

src/HistogramWindow.cpp

@@ -156,10 +156,7 @@ HistogramWindow::rideSelected()
 void
 HistogramWindow::rideAddorRemove(RideItem *)
 {
-    if (rangemode) {
-        stale = true;
-        updateChart();
-    }
+    stale = true;
 }
 
 void
@@ -186,11 +183,14 @@ HistogramWindow::zonesChanged()
     powerHist->replot();
 }
 
-void HistogramWindow::dateRangeChanged(DateRange)
+void HistogramWindow::dateRangeChanged(DateRange dateRange)
 {
-    if (!amVisible()) return;
+    // has it changed?
+    if (dateRange.from != cfrom || dateRange.to != cto) 
+        stale = true;
+
+    if (!amVisible() && !stale) return;
 
-    stale = true;
     updateChart();
 }
 
@@ -275,7 +275,8 @@ HistogramWindow::updateChart()
 #else
             source = new RideFileCache(mainWindow, myDateRange.from, myDateRange.to);
 #endif
-
+            cfrom = myDateRange.from;
+            cto = myDateRange.to;
             stale = false;
 
             if (old) delete old; // guarantee source pointer changes

src/HistogramWindow.h

@@ -115,6 +115,7 @@ class HistogramWindow : public GcWindow
         int powerRange, hrRange;
 
         bool stale;
+        QDate cfrom, cto;
         RideFileCache *source;
         bool interval;
 #ifdef GC_HAVE_LUCENE

src/LTMWindow.cpp

@@ -193,7 +193,10 @@ LTMWindow::rideSelected()
 void
 LTMWindow::refreshPlot()
 {
-    if (amVisible() == true) ltmPlot->setData(&settings);
+    if (amVisible() == true) {
+        ltmPlot->setData(&settings);
+        dirty = false;
+    }
 }
 
 // total redraw, reread data etc
@@ -234,7 +237,7 @@ LTMWindow::metricSelected()
 void
 LTMWindow::dateRangeChanged(DateRange range)
 {
-    if (!amVisible()) return;
+    if (!amVisible() && !dirty) return;
 
     settings.data = &results;
     settings.measures = &measures;