private void SwapIndex(int indexFrom, int indexTo)
{
if (indexFrom == indexTo)
{
return;
}
if (indexFrom < 0)
{
indexFrom = 0;
}
if (indexTo < 0)
{
indexTo = 0;
}
if (indexFrom > indexTo)
{
IntExtensions.Swap(ref indexFrom, ref indexTo);
}
var itemA = _points[indexFrom];
var itemB = _points[indexTo];
// note: these are mutable, so if we store the values in local scope
var posA = itemA.Position.Top + itemB.Position.Height;
var posB = itemA.Position.Top;
itemA.Reposition(new Point(0, posA));
itemB.Reposition(new Point(0, posB));
_points[indexFrom] = itemB;
_points[indexTo] = itemA;
}