Disable stack zoom controls when stacked view is disabled.

src/AllPlotWindow.cpp

@@ -657,8 +657,6 @@ AllPlotWindow::setAllPlotWidgets(RideItem *ride)
         scrollRight->hide();
 
         // show stacked view
-        stackZoomDown->setEnabled(true);
-        stackZoomUp->setEnabled(true);
         stackFrame->show();
 
     } else {
@@ -1073,17 +1071,36 @@ AllPlotWindow::resetStackedDatas()
 
 }
 
+bool
+AllPlotWindow::stackZoomUpShouldEnable(int sw)
+{
+    if (sw >= 200  || sw >= allPlot->rideItem->ride()->dataPoints().last()->secs/60) {
+        return false;
+    }
+    else {
+        return true;
+    }
+}
+
+bool
+AllPlotWindow::stackZoomDownShouldEnable(int sw)
+{
+    if (sw <= 4) {
+        return false;
+    }
+    else {
+        return true;
+    }
+}
+
 void
 AllPlotWindow::setStackZoomUp()
 {
     if (stackWidth<200 && stackWidth<allPlot->rideItem->ride()->dataPoints().last()->secs/60) {
 
         stackWidth = ceil(stackWidth * 1.25);
-        stackZoomDown->setEnabled(true);
         setupStackPlots();
 
-        if (stackWidth>=200  || stackWidth>=allPlot->rideItem->ride()->dataPoints().last()->secs/60)
-            stackZoomUp->setEnabled(false);
     }
 }
 
@@ -1093,10 +1110,8 @@ AllPlotWindow::setStackZoomDown()
     if (stackWidth>4) {
 
         stackWidth = floor(stackWidth / 1.25);
-        stackZoomUp->setEnabled(true);
         setupStackPlots();
 
-        if (stackWidth<=4) stackZoomDown->setEnabled(false);
     }
 }
 
@@ -1117,6 +1132,8 @@ AllPlotWindow::showStackChanged(int value)
     if (value) {
         // refresh plots
         resetStackedDatas();
+        stackZoomUp->setEnabled(stackZoomUpShouldEnable(stackWidth));
+        stackZoomDown->setEnabled(stackZoomDownShouldEnable(stackWidth));
 
         // now they are all set, lets replot them
         foreach(AllPlot *plot, allPlots) plot->replot();
@@ -1254,6 +1271,9 @@ AllPlotWindow::setupStackPlots()
 
     // we are now happy for a screen refresh to take place
     stackFrame->setUpdatesEnabled(true);
+
+    stackZoomUp->setEnabled(stackZoomUpShouldEnable(stackWidth));
+    stackZoomDown->setEnabled(stackZoomDownShouldEnable(stackWidth));
 }
 
 void

src/AllPlotWindow.h

@@ -140,6 +140,9 @@ class AllPlotWindow : public QWidget
     private slots:
 
         void addPickers(AllPlot *allPlot2);
+        bool stackZoomUpShouldEnable(int sw);
+        bool stackZoomDownShouldEnable(int sw);
+
         void plotPickerMoved(const QPoint &);
         void plotPickerSelected(const QPoint &);
 };