/// <summary>
/// Splites a multi part figure into single parts.
/// See Polygon Split.png.
/// </summary>
/// <param name="sourceSegments"></param>
/// <param name="obstacles"></param>
protected virtual ICollection<Polygon> SplitPolygon(List<LineSegment> sourceSegments, ObstacleCollection obstacles)
{
var verticesCombinations = new HashSet<Polygon>();
foreach (var switchPoint in SwitchPoints)
{
foreach (var endPoint in switchPoint.Value.EndPoints)
{
var startPoint = switchPoint.Key;
var polygon = new Polygon();
var remainingLines = new List<LineSegment>(sourceSegments);
var currentItem = startPoint;
var currentDirection = Direction.None;
do
{
if (currentItem == startPoint && polygon.Count > 0)
{
if (!verticesCombinations.Contains(polygon))
verticesCombinations.Add(polygon);
break;
}
if (polygon.Contains(currentItem))
break;
polygon.Add(currentItem);
LineSegment preferedLine;
if (currentItem == startPoint)
preferedLine = GetLine(currentItem, endPoint, true);
else
preferedLine = ChooseNextLine(currentItem, remainingLines, currentDirection);
if (preferedLine == null)
break;
currentItem = preferedLine.End;
currentDirection = preferedLine.Direction;
polygon.Lines.Add(preferedLine);
remainingLines.Remove(preferedLine);
} while (true);
}
}
RemoveUnnecessaryPolygons(verticesCombinations);
var forlornLines = GetPolygonForlornLines(sourceSegments, verticesCombinations);
obstacles.AddRange(forlornLines.Select(forlornLine => new LineObstacle(forlornLine.Start, forlornLine.End, Layer)));
return verticesCombinations;
}
//Polygon
/// <summary>
/// Creates a polygon out of a List of Lines.
/// </summary>
/// <param name="sourceSegments"></param>
/// <returns></returns>
public virtual Polygon CreatePolygon(IEnumerable<LineSegment> sourceSegments)
{
var polygon = new Polygon();
var lineSegments = new List<LineSegment>(sourceSegments);
var currentItem = lineSegments.First().Start;
var startPoint = currentItem;
var currentDirection = Direction.None;
while (lineSegments.Count > 0)
{
if (polygon.Count > 0 && startPoint == currentItem)
break;
var preferedLine = ChooseNextLine(currentItem, lineSegments, currentDirection);
if (preferedLine == null)
break;
lineSegments.Remove(preferedLine);
var previousItem = currentItem;
currentItem = preferedLine.End;
if (preferedLine.Direction == currentDirection)
continue;
currentDirection = preferedLine.Direction;
polygon.Add(previousItem);
polygon.Lines.Add(preferedLine);
}
return polygon;
}
