public MainWindow()
            : base(WindowType.Toplevel)
        {
            Build ();
            _model = new SettingsModel ();
            _renderer = new Cairo.CairoRenderer ();

            _drawingArea.AppPaintable = true;
            _drawingArea.DoubleBuffered = false;
            _drawingArea.ExposeEvent += OnExpose;

            _geometryWidthSpinButton.Value = _model.GeometyWidth;
            _geometryWidthSpinButton.Changed += OnGeometryWidthTextBoxChanged;

            _typeComboBox.AppendText("3");
            _typeComboBox.AppendText("4");
            _typeComboBox.Active = 0;
            _typeComboBox.Changed += OnTypeComboBoxChanged;

            _imageSelectButton.Clicked += OnImageSelectButtonClicked;

            RenderBaseImagePreview ();
        }