class_docstr: Constrained delaunay triangulation
  
  Implementation based on [1]_.
  
  Parameters
  ----------
  pts : array
      Nx2 array of points.
  edges : array
      Nx2 array of edges (dtype=int).
  
  Notes
  -----
  * Delaunay legalization is not yet implemented. This produces a proper
    triangulation, but adding legalisation would produce fewer thin
    triangles.
  * The pts and edges arrays may be modified.
  
  References
  ----------
  .. [1] Domiter, V. and Žalik, B. Sweep‐line algorithm for constrained
     Delaunay triangulation
class_docstr_tok: ["Constrained","delaunay","triangulation","Implementation","based","on","[","1","]","_.","Parameters","--","--","--","--","--","pts",":","array","Nx2","array","of","points",".","edges",":","array","Nx2","array","of","edges","(","dtype=int",")",".","Notes","--","--","-","*","Delaunay","legalization","is","not","yet","implemented",".","This","produces","a","proper","triangulation",",","but","adding","legalisation","would","produce","fewer","thin","triangles",".","*","The","pts","and","edges","arrays","may","be","modified",".","References","--","--","--","--","--","..","[","1","]","Domiter",",","V.","and","\u017dalik",",","B.","Sweep\u2010line","algorithm","for","constrained","Delaunay","triangulation"]
code: def __init__(self, pts, edges):
      self.pts = pts[:, :2].astype(np.float32)
      self.edges = edges
      if self.pts.ndim != 2 or self.pts.shape[1] != 2:
          raise TypeError(
              "pts argument must be ndarray of shape (N, 2)."
          )
      if self.edges.ndim != 2 or self.edges.shape[1] != 2:
          raise TypeError(
              "edges argument must be ndarray of shape (N, 2)."
          )
  
      # described in initialize()
      self._front = None
      self.tris = OrderedDict()
      self._edges_lookup = {}
  
imports: from __future__ import division, print_function
  from itertools import permutations
  import numpy
  from collections import OrderedDict
label_desc: Use image node_id 1 to create a new Triangulation object from inherited base classes: object with example: obj = Triangulation(pts, edges)