private static void ExpandFromStart(FlexElementCollection elements, double target)
{
var useLayoutRounding = elements.UseLayoutRounding;
if (useLayoutRounding)
{
target = target.LayoutRound(elements.Orientation, RoundingMode.MidPointFromZero);
}
if (elements.TryExpandToMaximum(target))
{
return;
}
var current = elements.Actual;
if (current.IsGreaterThanOrClose(elements.ActualMaximum))
{
return;
}
for (var index = 0; index < elements.Count; index++)
{
var item = elements[index];
var compensation = Math.Max(-item.ActualLength, Math.Min(target - current, item.ActualMaxLength - item.ActualLength));
item.ActualLength += compensation;
elements[index] = item;
current += compensation;
if (current.IsCloseTo(target, XamlConstants.LayoutComparisonPrecision))
{
break;
}
}
}
private void ExpandAllImpl(FlexElementCollection elements, double target)
{
var useLayoutRounding = elements.UseLayoutRounding;
var originalTarget = target;
var orientation = elements.Orientation;
if (useLayoutRounding)
{
target = target.LayoutRound(orientation, RoundingMode.MidPointFromZero);
}
if (elements.TryExpandToMaximum(target))
{
return;
}
target -= Sort(elements, FlexDistributeDirection.Expand);
try
{
var deadlock = true;
do
{
var tmpTarget = target;
for (var iItem = _currentCount - 1; iItem >= 0; iItem--)
{
var item = _sortedElements[iItem];
if (item.ActualLength * (iItem + 1) <= tmpTarget)
{
deadlock = false;
var success = true;
var avg = tmpTarget / (iItem + 1);
if (useLayoutRounding)
{
avg = avg.LayoutRound(orientation, RoundingMode.MidPointFromZero);
}
for (var jItem = iItem; jItem >= 0; jItem--)
{
var titem = _sortedElements[jItem];
if (avg < titem.MaxLength)
{
titem.ActualLength = avg;
}
else
{
titem.ActualLength = titem.MaxLength;
success = false;
}
_sortedElements[jItem] = titem;
if (success)
{
continue;
}
target -= titem.ActualLength;
RemoveAt(elements, jItem);
}
if (success)
{
return;
}
break;
}
tmpTarget -= item.ActualLength;
}
} while (_currentCount > 0 && deadlock == false);
}
finally
{
RestoreOrder(elements);
DistributeRoundingError(elements, elements.Actual - originalTarget);
}
}