public override IEnumerable <FocusNode> sortDescendants(IEnumerable <FocusNode> descendants)
{
D.assert(descendants != null);
if (descendants.Count() <= 1)
{
return(descendants);
}
List <_ReadingOrderSortData> data = new List <_ReadingOrderSortData>();
foreach (FocusNode node in descendants)
{
data.Add(new _ReadingOrderSortData(node));
}
List <FocusNode> sortedList = new List <FocusNode>();
List <_ReadingOrderSortData> unplaced = data;
_ReadingOrderSortData current = _pickNext(unplaced);
sortedList.Add(current.node);
unplaced.Remove(current);
while (unplaced.isNotEmpty())
{
_ReadingOrderSortData next = _pickNext(unplaced);
current = next;
sortedList.Add(current.node);
unplaced.Remove(current);
}
return(sortedList);
}
public _ReadingOrderSortData _pickNext(List <_ReadingOrderSortData> candidates)
{
FocusTravesalUtils.mergeSort <_ReadingOrderSortData>(candidates, compare: (_ReadingOrderSortData a, _ReadingOrderSortData b) => a.rect.top.CompareTo(b.rect.top));
_ReadingOrderSortData topmost = candidates.First();
List <_ReadingOrderSortData> inBand(_ReadingOrderSortData current, IEnumerable <_ReadingOrderSortData> _candidates)
{
Rect band = Rect.fromLTRB(float.NegativeInfinity, current.rect.top, float.PositiveInfinity, current.rect.bottom);
return(LinqUtils <_ReadingOrderSortData> .WhereList(_candidates, ((_ReadingOrderSortData item) => {
return !item.rect.intersect(band).isEmpty;
})));
}
List <_ReadingOrderSortData> inBandOfTop = inBand(topmost, candidates);
D.assert(topmost.rect.isEmpty || inBandOfTop.isNotEmpty());
if (inBandOfTop.Count <= 1)
{
return(topmost);
}
TextDirection nearestCommonDirectionality = _ReadingOrderSortData.commonDirectionalityOf(inBandOfTop);
_ReadingOrderSortData.sortWithDirectionality(inBandOfTop, nearestCommonDirectionality);
List <_ReadingOrderDirectionalGroupData> bandGroups = _collectDirectionalityGroups(inBandOfTop);
if (bandGroups.Count == 1)
{
return(bandGroups.First().members.First());
}
_ReadingOrderDirectionalGroupData.sortWithDirectionality(bandGroups, nearestCommonDirectionality);
return(bandGroups.First().members.First());
}