private Geometry HandleClosedPaths(IImmutableList<Tuple<Coords, Coords, Direction>> combinedLineSegments, PathSegmentCollection segments)
{
var lastLineSegment = combinedLineSegments.Last();
var firstLineSegment = combinedLineSegments.First();
if (Equals(firstLineSegment.Item1, lastLineSegment.Item2))
{
// Only the 'O' tetra stick has a closed line.
// The following code relies on the 'O' tetra stick
// line going Up then Right then Down then Left.
// Ideally, it should not rely on this but life is
// too short!
Debug.Assert(segments.Count%2 == 0);
var halfLength = segments.Count/2;
var innerSegments = segments.Skip(halfLength).ToList();
var outerSegments = segments.Take(halfLength).ToList();
var cornerSegments = new PathSegmentCollection();
AddCornerDownThenRight(cornerSegments, lastLineSegment.Item2);
outerSegments[0] = cornerSegments[0];
innerSegments.RemoveAt(0);
innerSegments.Add(cornerSegments[1]);
var outerGeometry = new PathGeometry
{
Figures = new PathFigureCollection
{
new PathFigure
{
StartPoint = CoordsToInsetLowerLeftVertical(lastLineSegment.Item2),
Segments = new PathSegmentCollection(outerSegments)
}
}
};
var innerGeometry = new PathGeometry
{
Figures = new PathFigureCollection
{
new PathFigure
{
StartPoint = CoordsToInsetLowerRightVertical(lastLineSegment.Item2),
Segments = new PathSegmentCollection(innerSegments)
}
}
};
return new CombinedGeometry(GeometryCombineMode.Exclude, outerGeometry, innerGeometry);
}
return new PathGeometry
{
Figures = new PathFigureCollection
{
new PathFigure
{
StartPoint = GetStartingPoint(combinedLineSegments),
Segments = segments
}
}
};
}