Add a circle on the selected graph where you double clicked on it. Also show text with the coordinates at the clicked graph location

re/graphingwindow.cpp

@@ -42,11 +42,24 @@ GraphingWindow::GraphingWindow(const QVector<CANFrame> *frames, QWidget *parent)
     ui->graphingView->legend->setSelectedFont(legendSelectedFont);
     ui->graphingView->legend->setSelectableParts(QCPLegend::spItems); // legend box shall not be selectable, only legend items
 
+    locationText = new QCPItemText(ui->graphingView);
+    locationText->position->setType(QCPItemPosition::ptAxisRectRatio);
+    locationText->position->setCoords(QPointF(0.16, 0.03));
+    locationText->setText("X: 0  Y: 0");
+    locationText->setFont(legendSelectedFont);
+
+    itemTracer = new QCPItemTracer(ui->graphingView);
+    itemTracer->setInterpolating(true);
+    itemTracer->setVisible(false); //no graph selected yet
+    itemTracer->setStyle(QCPItemTracer::tsCircle);
+    itemTracer->setSize(20);
+
     // connect slot that ties some axis selections together (especially opposite axes):
     connect(ui->graphingView, SIGNAL(selectionChangedByUser()), this, SLOT(selectionChanged()));
     //connect up the mouse controls
     connect(ui->graphingView, SIGNAL(mousePress(QMouseEvent*)), this, SLOT(mousePress()));
     connect(ui->graphingView, SIGNAL(plottableDoubleClick(QCPAbstractPlottable*,int,QMouseEvent*)), this, SLOT(plottableDoubleClick(QCPAbstractPlottable*,int,QMouseEvent*)));
+    connect(ui->graphingView, SIGNAL(plottableClick(QCPAbstractPlottable*,int,QMouseEvent*)), this, SLOT(plottableClick(QCPAbstractPlottable*,int,QMouseEvent*)));
     connect(ui->graphingView, SIGNAL(mouseWheel(QWheelEvent*)), this, SLOT(mouseWheel()));
 
     // make bottom and left axes transfer their ranges to top and right axes:
@@ -208,6 +221,15 @@ void GraphingWindow::updatedFrames(int numFrames)
     }
 }
 
+void GraphingWindow::plottableClick(QCPAbstractPlottable* plottable, int dataIdx, QMouseEvent* event)
+{
+    qDebug() << "plottableClick";
+    double x, y;
+    QCPGraph *graph = reinterpret_cast<QCPGraph *>(plottable);
+    graph->pixelsToCoords(event->localPos(), x, y);
+    locationText->setText("X: " + QString::number(x, 'f', 3) + " Y: " + QString::number(y, 'f', 3));
+}
+
 void GraphingWindow::plottableDoubleClick(QCPAbstractPlottable* plottable, int dataIdx, QMouseEvent* event)
 {
     Q_UNUSED(dataIdx);
@@ -218,6 +240,15 @@ void GraphingWindow::plottableDoubleClick(QCPAbstractPlottable* plottable, int d
     id = plottable->property("id").toInt();
     if (secondsMode) emit sendCenterTimeID(id, coord);
     else emit sendCenterTimeID(id, coord / 1000000.0);
+
+    double x, y;
+    QCPGraph *graph = reinterpret_cast<QCPGraph *>(plottable);
+    graph->pixelsToCoords(event->localPos(), x, y);
+    locationText->setText("X: " + QString::number(x) + " Y: " + QString::number(y));
+
+    itemTracer->setGraph(graph);
+    itemTracer->setVisible(true);
+    itemTracer->setGraphKey(x);
 }
 
 void GraphingWindow::gotCenterTimeID(int32_t ID, double timestamp)

re/graphingwindow.h

@@ -46,6 +46,7 @@ private slots:
     void legendDoubleClick(QCPLegend* legend, QCPAbstractLegendItem* item);
     void legendSingleClick(QCPLegend* legend, QCPAbstractLegendItem* item);
     void plottableDoubleClick(QCPAbstractPlottable* plottable,int dataIdx, QMouseEvent* event);
+    void plottableClick(QCPAbstractPlottable* plottable, int dataIdx, QMouseEvent* event);
     void selectionChanged();
     void mousePress();
     void mouseWheel();
@@ -79,6 +80,8 @@ private:
     QList<GraphParams> graphParams;
     QPen selectedPen;
     QCPSelectionDecorator *selDecorator;
+    QCPItemText *locationText;
+    QCPItemTracer *itemTracer;
     bool needScaleSetup; //do we need to set x,y graphing extents?
     bool secondsMode;
     bool useOpenGL;