protected override Size ArrangeOverride(Size finalSize)
{
Size result = finalSize;
if (ScrollViewer is {} scrollViewer)
{
#if SCROLLVIEWER_SUPPORTS_ANCHORING
if (SharedHelpers.IsRS5OrHigher())
{
// No-op when running on RS5 and above. ScrollViewer can do anchoring on its own.
scrollViewer.Arrange(new Rect(0, 0, finalSize.Width, finalSize.Height));
}
else
#endif
{
var shouldApplyPendingChangeView = scrollViewer != default && HasPendingBringIntoView && !m_pendingBringIntoView.ChangeViewCalled;
Rect anchorElementRelativeBounds = default;
var anchorElement =
// BringIntoView takes precedence over tracking.
shouldApplyPendingChangeView
? null
:
// Pick the best candidate depending on HorizontalAnchorRatio and VerticalAnchorRatio.
// The best candidate is the element that's the closest to the edge of interest.
GetAnchorElement(out anchorElementRelativeBounds);
scrollViewer.Arrange(new Rect(0, 0, finalSize.Width, finalSize.Height));
m_pendingViewportShift = 0.0;
if (shouldApplyPendingChangeView)
{
ApplyPendingChangeView(scrollViewer);
}
else if (anchorElement != default)
{
// The anchor element might have changed its position relative to us.
// If that's the case, we should shift the viewport to follow it as much as possible.
m_pendingViewportShift = TrackElement(anchorElement, anchorElementRelativeBounds, scrollViewer);
}
else if (scrollViewer != default)
{
m_pendingBringIntoView.Reset();
}
m_candidates.Clear();
m_isAnchorElementDirty = true;
_postArrange?.Invoke(this);
}
}
return(result);
}
private void SetScrollViewerProperties(string scrollViewerName, SerialDisposable revoker)
{
if (SharedHelpers.IsRS5OrHigher())
{
if (GetTemplateChild(scrollViewerName) is ScrollViewer scrollViewer)
{
if (SharedHelpers.IsScrollContentPresenterSizesContentToTemplatedParentAvailable())
{
scrollViewer.Loaded += OnScrollViewerLoaded;
revoker.Disposable = Disposable.Create(() => scrollViewer.Loaded -= OnScrollViewerLoaded);
}
}
}
}
void SetScrollViewerProperties(string scrollViewerName, CompositeDisposable disposable)
{
if (SharedHelpers.IsRS5OrHigher())
{
if (GetTemplateChild(scrollViewerName) is ScrollViewer scrollViewer)
{
if (SharedHelpers.IsScrollContentPresenterSizesContentToTemplatedParentAvailable())
{
// revoker = scrollViewer.Loaded(auto_revoke, { this, &OnScrollViewerLoaded });
}
if (SharedHelpers.IsScrollViewerReduceViewportForCoreInputViewOcclusionsAvailable())
{
scrollViewer.ReduceViewportForCoreInputViewOcclusions = true;
}
}
}
}