/*
* Graph improvement
*/
/// <summary>
/// connect open boundary vertices within distThresh, by inserting new segments
/// </summary>
public void ConnectOpenBoundaries(double distThresh)
{
int max_vid = Graph.MaxVertexID;
for (int vid = 0; vid < max_vid; ++vid)
{
if (Graph.IsBoundaryVertex(vid) == false)
{
continue;
}
Vector2d v = Graph.GetVertex(vid);
int snap_with = find_nearest_boundary_vertex(v, distThresh, vid);
if (snap_with != -1)
{
Vector2d v2 = Graph.GetVertex(snap_with);
Insert(v, v2);
}
}
}
/// <summary>
/// Decompose graph into simple polylines and polygons.
/// </summary>
public static Curves ExtractCurves(DGraph2 graph)
{
Curves c = new Curves();
c.Loops = new List <Polygon2d>();
c.Paths = new List <PolyLine2d>();
HashSet <int> used = new HashSet <int>();
// find boundary and junction vertices
HashSet <int> boundaries = new HashSet <int>();
HashSet <int> junctions = new HashSet <int>();
foreach (int vid in graph.VertexIndices())
{
if (graph.IsBoundaryVertex(vid))
{
boundaries.Add(vid);
}
if (graph.IsJunctionVertex(vid))
{
junctions.Add(vid);
}
}
// walk paths from boundary vertices
foreach (int start_vid in boundaries)
{
int vid = start_vid;
int eid = graph.GetVtxEdges(vid)[0];
if (used.Contains(eid))
{
continue;
}
PolyLine2d path = new PolyLine2d();
path.AppendVertex(graph.GetVertex(vid));
while (true)
{
used.Add(eid);
Index2i next = NextEdgeAndVtx(eid, vid, graph);
eid = next.a;
vid = next.b;
path.AppendVertex(graph.GetVertex(vid));
if (boundaries.Contains(vid) || junctions.Contains(vid))
{
break; // done!
}
}
c.Paths.Add(path);
}
// ok we should be done w/ boundary verts now...
boundaries.Clear();
foreach (int start_vid in junctions)
{
foreach (int outgoing_eid in graph.VtxEdgesItr(start_vid))
{
if (used.Contains(outgoing_eid))
{
continue;
}
int vid = start_vid;
int eid = outgoing_eid;
PolyLine2d path = new PolyLine2d();
path.AppendVertex(graph.GetVertex(vid));
while (true)
{
used.Add(eid);
Index2i next = NextEdgeAndVtx(eid, vid, graph);
eid = next.a;
vid = next.b;
path.AppendVertex(graph.GetVertex(vid));
if (eid == int.MaxValue || junctions.Contains(vid))
{
break; // done!
}
}
c.Paths.Add(path);
}
}
// all that should be left are continuous loops...
foreach (int start_eid in graph.EdgeIndices())
{
if (used.Contains(start_eid))
{
continue;
}
int eid = start_eid;
Index2i ev = graph.GetEdgeV(eid);
int vid = ev.a;
Polygon2d poly = new Polygon2d();
poly.AppendVertex(graph.GetVertex(vid));
while (true)
{
used.Add(eid);
Index2i next = NextEdgeAndVtx(eid, vid, graph);
eid = next.a;
vid = next.b;
poly.AppendVertex(graph.GetVertex(vid));
if (eid == int.MaxValue || junctions.Contains(vid))
{
throw new Exception("how did this happen??");
}
if (used.Contains(eid))
{
break;
}
}
poly.RemoveVertex(poly.VertexCount - 1);
c.Loops.Add(poly);
}
return(c);
}