Added zoom functionality to scopes. There is a minor bias error when zooming with the legends activated.

This is due principally to the fact that retreiving the Qt coordinate in the frame
references to a slightly different system from Qwt invTranformation when the
legend is active.

ground/openpilotgcs/src/plugins/scope/scopegadgetwidget.cpp

@@ -51,6 +51,7 @@
 #include <QtGui/QVBoxLayout>
 #include <QtGui/QPushButton>
 #include <QMutexLocker>
+#include <QWheelEvent>
 
 //using namespace Core;
 
@@ -65,8 +66,8 @@ ScopeGadgetWidget::ScopeGadgetWidget(QWidget *parent) : QwtPlot(parent)
     replotTimer = new QTimer(this);
     connect(replotTimer, SIGNAL(timeout()), this, SLOT(replotNewData()));
 
-    // Listen to telemetry connection/disconnection events, no point
+    // Listen to telemetry connection/disconnection events, no point in
-    // running the scopes if we are not connected and not replaying logs
+    // running the scopes if we are not connected and not replaying logs.
     // Also listen to disconnect actions from the user
     Core::ConnectionManager *cm = Core::ICore::instance()->connectionManager();
     connect(cm, SIGNAL(deviceAboutToDisconnect()), this, SLOT(stopPlotting()));
@@ -124,12 +125,17 @@ void ScopeGadgetWidget::mouseReleaseEvent(QMouseEvent *e)
 
 void ScopeGadgetWidget::mouseDoubleClickEvent(QMouseEvent *e)
 {
+    //On double-click, toggle legend
     mutex.lock();
     if (legend())
         deleteLegend();
     else
         addLegend();
     mutex.unlock();
+
+    //On double-click, reset plot zoom
+    setAxisAutoScale(QwtPlot::yLeft, true);
+
     update();
 
 	QwtPlot::mouseDoubleClickEvent(e);
@@ -142,6 +148,33 @@ void ScopeGadgetWidget::mouseMoveEvent(QMouseEvent *e)
 
 void ScopeGadgetWidget::wheelEvent(QWheelEvent *e)
 {
+    //Change zoom on scroll wheel event
+    QwtInterval yInterval=axisInterval(QwtPlot::yLeft);
+    if (yInterval.minValue() != yInterval.maxValue()) //Make sure that the two values are never the same. Sometimes axisInterval returns (0,0)
+    {
+        //Determine what y value to zoom about. NOTE, this approach has a bug that the in that
+        //the value returned by Qt includes the legend, whereas the value transformed by Qwt
+        //does *not*. Thus, when zooming with a legend, there will always be a small bias error.
+        //In practice, this seems not to be a UI problem.
+        QPoint mouse_pos=e->pos(); //Get the mouse coordinate in the frame
+        double zoomLine=invTransform(QwtPlot::yLeft, mouse_pos.y()); //Transform the y mouse coordinate into a frame value.
+
+        double zoomScale=1.1; //THIS IS AN ARBITRARY CONSTANT, AND PERHAPS SHOULD BE IN A DEFINE INSTEAD OF BURIED HERE
+
+        mutex.lock(); //DOES THIS mutex.lock NEED TO BE HERE? I DON'T KNOW, I JUST COPIED IT FROM THE ABOVE CODE
+        // Set the scale
+        if (e->delta()<0){
+            setAxisScale(QwtPlot::yLeft,
+                         (yInterval.minValue()-zoomLine)*zoomScale+zoomLine,
+                         (yInterval.maxValue()-zoomLine)*zoomScale+zoomLine );
+        }
+        else{
+            setAxisScale(QwtPlot::yLeft,
+                         (yInterval.minValue()-zoomLine)/zoomScale+zoomLine,
+                         (yInterval.maxValue()-zoomLine)/zoomScale+zoomLine );
+        }
+        mutex.unlock();
+    }
     QwtPlot::wheelEvent(e);
 }
 
@@ -412,7 +445,7 @@ void ScopeGadgetWidget::addCurvePlot(QString uavObject, QString uavFieldSubField
     //Keep the curve details for later
     m_curvesData.insert(curveNameScaled, plotData);
 
-    //Link to the signal of new data only if this UAVObject has not been to connected yet
+    //Link to the new signal data only if this UAVObject has not been connected yet
     if (!m_connectedUAVObjects.contains(obj->getName())) {
         m_connectedUAVObjects.append(obj->getName());
         connect(obj, SIGNAL(objectUpdated(UAVObject*)), this, SLOT(uavObjectReceived(UAVObject*)));
@@ -470,6 +503,7 @@ void ScopeGadgetWidget::replotNewData()
 	replot();
 }
 
+/*
 void ScopeGadgetWidget::setupExamplePlot()
 {
     preparePlot(SequentialPlot);
@@ -514,6 +548,7 @@ void ScopeGadgetWidget::setupExamplePlot()
 		replot();
 	mutex.unlock();
 }
+*/
 
 void ScopeGadgetWidget::clearCurvePlots()
 {