/// <summary>
/// Initializes a new instance of the <see cref="EventQueue" /> class.
/// </summary>
/// <param name="source">The source coordinates representing multiple line strings.</param>
/// <exception cref="System.ArgumentNullException">The source is null.</exception>
public EventQueue(IEnumerable <IList <Coordinate> > source)
{
// source: http://geomalgorithms.com/a09-_intersect-3.html
if (source == null)
{
throw new ArgumentNullException("source", "The source is null.");
}
_comparer = new CoordinateComparer();
_eventHeap = new EventHeap();
Int32 index = 0, compare;
foreach (IList <Coordinate> coordinateList in source)
{
if (coordinateList == null || coordinateList.Count < 2)
{
continue;
}
for (Int32 i = 0; i < coordinateList.Count - 1; i++)
{
EndPointEvent firstEvent = new EndPointEvent {
Edge = index, Vertex = coordinateList[i]
};
EndPointEvent secondEvent = new EndPointEvent {
Edge = index, Vertex = coordinateList[i + 1]
};
compare = _comparer.Compare(coordinateList[i], coordinateList[i + 1]);
if (compare == 0)
{
continue;
}
if (compare < 0)
{
firstEvent.Type = EventType.Left;
secondEvent.Type = EventType.Right;
}
else
{
firstEvent.Type = EventType.Right;
secondEvent.Type = EventType.Left;
}
_eventHeap.Insert(firstEvent);
_eventHeap.Insert(secondEvent);
index++;
}
index++;
}
}
/// <summary>
/// Adds an intersection event to the queue.
/// </summary>
/// <param name="intersectionEvent">The intersection event.</param>
/// <exception cref="System.ArgumentNullException">The intersection event is null.</exception>
public void Add(IntersectionEvent intersectionEvent)
{
if (intersectionEvent == null)
{
throw new ArgumentNullException("intersectionEvent", "The intersection event is null.");
}
_eventHeap.Insert(intersectionEvent);
}