/// <summary>
/// Setup the slide edges
/// </summary>
private void calcSlideEdges()
{
if (_slideStartLocations == null)
{
double sum = 0;
var widths = Enumerable.Range(0, SlideStrip.Items.Count)
.Select(index => SlideStrip.ContainerFromIndex(index) as ContentPresenter)
.Select(container => _orientation == FullPanelOrientation.Horizontal ? container.ActualWidth : container.ActualHeight)
.Select(w => sum += w);
_slideStartLocations = widths
.ToArray();
}
}
public FullTalkAsStripView()
{
this.InitializeComponent();
this.WhenActivated(disposeOfMe =>
{
disposeOfMe(this.OneWayBind(ViewModel, x => x.Pages, y => y.SlideStrip.ItemsSource));
// If the ESC key or backbutton is hit, we want to navigate back.
var keyrelease = SlideStrip.Events().KeyDown
.Where(keys => ViewModel != null);
keyrelease
.Where(keys => keys.Key == VirtualKey.Escape)
.Do(keys => keys.Handled = true)
.Subscribe(e => Locator.Current.GetService <RoutingState>().NavigateBack.Execute(null));
backButton.WireAsBackButton();
// Forward and backwards arrows.
// Tricky because if we calcCurrentPage while in the middle of the scroll we won't
// get a scroll to the item we want. So we need to aggregate those while running.
var isScrollInProgress = theScrollViewer
.Events().ViewChanged
.Select(sc => sc.IsIntermediate);
var keysByScrolling = keyrelease
.Select(k => Tuple.Create(k, calcKeyMoveRequest(k)))
.Where(k => k.Item2 != 0)
.Do(k => k.Item1.Handled = true)
.Select(k => k.Item2)
.BatchByStream(isScrollInProgress);
keysByScrolling
.Where(info => !info.Item1)
.Subscribe(info => info.Item2.Subscribe(delta => ViewModel.PageMove.Execute(calcCurrentPage() + delta)));
keysByScrolling
.Where(info => info.Item1)
.SelectMany(async info => await info.Item2.Sum())
.Where(d => d != 0)
.ObserveOn(RxApp.MainThreadScheduler)
.Subscribe(delta => ViewModel.PageMove.Execute(delta + calcCurrentPage()));
// We can't tell what size things are in here (which we need for scrolling, etc.) until
// we have a clue as to what the layout is. So, we have to wait for that to go.
var widthOfItemsChanged = SlideStrip.Events().SizeChanged
.Select(_ => SlideStrip.ActualHeight)
.Throttle(TimeSpan.FromMilliseconds(100))
.DistinctUntilChanged();
disposeOfMe(widthOfItemsChanged
.Subscribe(_ => _slideStartLocations = null));
// And when we get asked to bring a page into view...
disposeOfMe(this.WhenAny(x => x.ViewModel, x => x.Value)
.Where(x => x != null)
.Subscribe(vm =>
{
vm.MoveToPage
.CombineLatest(widthOfItemsChanged, (pn, width) => pn)
.ObserveOn(RxApp.MainThreadScheduler)
.Where(pn => SlideStrip.ContainerFromIndex(0) != null)
.Select(pn => getSlideEdge(pn))
.Subscribe(loc =>
{
if (_orientation == FullPanelOrientation.Horizontal)
{
theScrollViewer.ChangeView(loc, null, null);
}
else
{
theScrollViewer.ChangeView(null, loc, null);
}
});
}));
// Make the back button visible if there is any movement - scrolling or otherwise.
var buttonRelatedMovement =
Observable.Merge(
this.Events().PointerMoved.Select(x => Unit.Default),
this.Events().Tapped.Select(x => Unit.Default)
);
var makeVisible = buttonRelatedMovement
.Select(x => true);
var makeInvisible = buttonRelatedMovement
.Select(x => Observable.Return(false).Delay(TimeSpan.FromSeconds(3)))
.Switch();
Observable.Merge(makeVisible, makeInvisible)
.DistinctUntilChanged()
.ObserveOn(RxApp.MainThreadScheduler)
.Subscribe(v => backButton.Visibility = v ? Windows.UI.Xaml.Visibility.Visible : Windows.UI.Xaml.Visibility.Collapsed);
backButton.Visibility = Windows.UI.Xaml.Visibility.Collapsed;
// Setup the rendering helper - when they are in frame, cause a rendering to happen. When they
// are out of frame, then turn off showing everything!
_holder = new OnScreenTrackingHelper(
theScrollViewer,
(uiElement, inViewPort) =>
{
if (uiElement is PDFPageUserControl)
{
(uiElement as PDFPageUserControl).ShowPDF = inViewPort;
}
}
)
{
ItemsWaitingInTheWings = 2
};
this.Events().Unloaded
.Subscribe(t => _holder.Unload());
// We want to capture key strokes, etc. By default we don't have
// the focus, so grab it.
Focus(Windows.UI.Xaml.FocusState.Programmatic);
// The orientation of this pannel will affect how we calc the arrow key stuff.
_orientation = theScrollViewer.VerticalScrollMode == ScrollMode.Disabled ? FullPanelOrientation.Horizontal : FullPanelOrientation.Vertical;
});
}
