public MainImageViewModel(IContainerExtension container, IRegionManager regionManager)
        {
            _container     = container;
            _regionManager = regionManager;

            ImageSource = MainImage
                          .ObserveProperty(x => x.ImageSource)
                          .ToReadOnlyReactiveProperty();

            ImageSource.Subscribe(x => InspectLinePoints.SetSourceSize(x.PixelWidth, x.PixelHeight));

            // Viewの非表示時のクリア
            LineLevels.ObserveProperty(x => x.IsShowingView).Where(b => !b)
            .Subscribe(_ =>
            {
                InspectLinePoints.ClearPoints();        // 画像上のLine表示
                LineLevels.ReleaseLinePoints();         // OxyPlot図(次回表示用)
            });

            // マウス移動開始
            MouseDown.Where(_ => LineLevels.IsShowingView)
            .Subscribe(p => InspectLinePoints.SetPoint1(p.X, p.Y));

            // マウス移動中
            var mouseMove = MouseDown.Merge(MouseDown.SelectMany(MouseMove.TakeUntil(MouseUp)))
                            .Where(_ => LineLevels.IsShowingView);

            // ViewのLine表示は常時更新
            mouseMove.Subscribe(p => InspectLinePoints.SetPoint2(p.X, p.Y));

            // Line画素値の取得は重いので計算を間引く
            mouseMove
            .Throttle(TimeSpan.FromMilliseconds(500))     // 指定期間分だけ値が通過しなかったら最後の一つを流す
            .Subscribe(_ => LineLevels.SetLinePointsRatio(InspectLinePoints.GetPointsRatio()));
        }