Native control outputs point description, basic plotting works.

main.cpp

 public:
     QmlWindow(QWidget *parent = NULL);
     Q_INVOKABLE QAction *addMenuItem(QString menu, QString item);
+signals:
+    void newPoint(QVariantMap pointDescription);
 private:
     QHash<QString,QMenu *> menus;
 };
 
 QmlWindow::QmlWindow(QWidget *parent) : QMainWindow(parent)
 {
-
+    QmlApplicationViewer *viewer = new QmlApplicationViewer;
+    viewer->setOrientation(QmlApplicationViewer::ScreenOrientationAuto);
+    viewer->rootContext()->setContextProperty("window", this);
+    viewer->setSource(QUrl("qrc:/qml/qml/BrewPlot/main.qml"));
+    qApp->connect(viewer->engine(), SIGNAL(quit()), SLOT(quit()));
+    QWidget *central = new QWidget;
+    QHBoxLayout *layout = new QHBoxLayout;
+    NewPointControl *control = new NewPointControl;
+    layout->addWidget(control);
+    layout->addWidget(viewer);
+    central->setLayout(layout);
+    setCentralWidget(central);
+    viewer->setMinimumSize(viewer->sizeHint());
+    connect(control, SIGNAL(newPoint(QVariantMap)),
+            this, SIGNAL(newPoint(QVariantMap)));
 }
 
 QAction *QmlWindow::addMenuItem(QString menu, QString item)
 
     QmlWindow *window = new QmlWindow(NULL);
     window->setWindowTitle("BrewPlot");
-    QmlApplicationViewer *viewer = new QmlApplicationViewer;
-    viewer->setOrientation(QmlApplicationViewer::ScreenOrientationAuto);
-    viewer->rootContext()->setContextProperty("window", window);
-    viewer->setSource(QUrl("qrc:/qml/qml/BrewPlot/main.qml"));
-    app.connect(viewer->engine(), SIGNAL(quit()), SLOT(quit()));
-    QWidget *central = new QWidget;
-    QHBoxLayout *layout = new QHBoxLayout;
-    NewPointControl *control = new NewPointControl;
-    layout->addWidget(control);
-    layout->addWidget(viewer);
-    central->setLayout(layout);
-    window->setCentralWidget(central);
-    viewer->setMinimumSize(viewer->sizeHint());
     window->show();
 
     return app.exec();

newpointcontrol.cpp

 #include "newpointcontrol.h"
 
 NewPointControl::NewPointControl(QWidget *parent) :
-    QWidget(parent)
+    QWidget(parent), groundsMass(new QLineEdit), brewMass(new QLineEdit),
+    tds(new QLineEdit)
 {
     QVBoxLayout *layout = new QVBoxLayout;
     QFormLayout *flayout = new QFormLayout;
-    QLineEdit *groundsMass = new QLineEdit;
-    QLineEdit *brewMass = new QLineEdit;
-    QLineEdit *tds = new QLineEdit;
     QPushButton *plot = new QPushButton(tr("Plot"));
     flayout->addRow(tr("Mass of ground coffee:"), groundsMass);
     flayout->addRow(tr("Mass of brewed coffee:"), brewMass);
     layout->addWidget(plot);
     layout->addStretch();
     setLayout(layout);
+    connect(plot, SIGNAL(clicked()), this, SLOT(plotButtonClicked()));
+}
+
+void NewPointControl::plotButtonClicked()
+{
+    QVariantMap pointDescription;
+    pointDescription.insert("groundMass", groundsMass->text());
+    pointDescription.insert("brewedMass", brewMass->text());
+    pointDescription.insert("ptds", tds->text());
+    pointDescription.insert("color", "red");
+    double extraction = (brewMass->text().toDouble() *
+            (tds->text().toDouble() / 100)) /
+            groundsMass->text().toDouble();
+    pointDescription.insert("extraction", extraction);
+    emit newPoint(pointDescription);
 }

newpointcontrol.h

 #define NEWPOINTCONTROL_H
 
 #include <QWidget>
+#include <QVariant>
+#include <QLineEdit>
 
 class NewPointControl : public QWidget
 {
     Q_OBJECT
 public:
     explicit NewPointControl(QWidget *parent = 0);
-    
 signals:
-    
+    void newPoint(QVariantMap pointDescription);
 public slots:
-    
+    void plotButtonClicked();
+private:
+    QLineEdit *groundsMass;
+    QLineEdit *brewMass;
+    QLineEdit *tds;
 };
 
 #endif // NEWPOINTCONTROL_H

qml/BrewPlot/main.qml

             graph.setFitVisible(showLeastSquares.checked);
             lsfrow.visible = showLeastSquares.checked;
         });
+        window.newPoint.connect(function(pointDescription) {
+            graph.plotPoint(pointDescription.extraction,
+                            pointDescription.ptds / 100,
+                            pointDescription.color)
+            dataviewModel.append(pointDescription)
+        });
     }
 }