private IObservable <T> Search(IEnvelop envelope, int zoomLevel)
{
var minMargin = ZoomHelper.GetMinMargin(zoomLevel);
return(Observable.Create <T>(observer =>
{
var node = Root;
if (!envelope.Intersects(node.Envelope))
{
observer.OnCompleted();
return Disposable.Empty;
}
var nodesToSearch = new Stack <RTreeNode>();
while (node != null && node.Envelope != null)
{
if (node.Children != null)
{
foreach (var child in node.Children)
{
var childEnvelope = child.Envelope;
if (envelope.Intersects(childEnvelope))
{
if (node.IsLeaf && childEnvelope.Margin >= minMargin)
{
observer.OnNext(child.Data);
}
else if (envelope.Contains(childEnvelope))
{
Collect(child, minMargin, observer);
}
else
{
nodesToSearch.Push(child);
}
}
}
}
node = nodesToSearch.TryPop();
}
observer.OnCompleted();
return Disposable.Empty;
}));
}