activate grid button and widget size

src/Vtk/vtkQViewport.h

@@ -3,6 +3,7 @@
 
 #include <QWidget>
 #include <QVTKOpenGLNativeWidget.h>
+#include <QPushButton>
 
 #include <vtkCornerAnnotation.h>
 #include <vtkOrientationMarkerWidget.h>
@@ -41,10 +42,17 @@ public:
     virtual vtkRenderWindowInteractor*  GetInteractor() override;
     QVTKOpenGLNativeWidget*     GetWidget()      { return m_VtkWidget; }
 
+protected:
+    virtual void resizeEvent(QResizeEvent* event) override;
+
+private slots:
+    void onGridButtonClicked();
+
 private:
     void SetupPipeline();
 
     QVTKOpenGLNativeWidget*             m_VtkWidget;
+    QPushButton*                        m_GridButton;
 };
 
 } // namespace Vtk