Intersection points of a DEdge and Region?

Comments

• Matthias

  November 2019

  Hi tok,

  you mean, the intersection with the polygon outline?

  If you want good performance, there is no real option currently. If you're happy with Python performance, you could iterate over the Polygon's edges and use Edge#intersect:

  dbu = 0.001  # should use layout.dbu
  
  region = pya.Region()
  region.insert(pya.Box(0, 0, 1000, 2000))
  
  edge = pya.DEdge(-0.1, 0.5, 0.5, 0.5)
  
  dbu_trans = pya.CplxTrans(dbu)
  
  intersection_points = []
  
  for poly in region.each():
    for pe in poly.transformed(dbu_trans).each_edge():
      if pe.intersect(edge):
        intersection_points.append(pe.intersection_point(edge))
  
  print(repr(intersection_points))
  

  Matthias
• tok

  November 2019

  Thanks for answering! Yes, this is the way I'm doing it now. As for now I'm only looking for intersections with a rectangle, so this solution is good enough. I thought that at the core of the boolean operations there must be something like this but I guess it is just not accessible by the API.
• Matthias

  November 2019

  Yes, internally there is code for this.

  Basically it's even available when you perform a boolean "AND" between two edge sets - one with the polygon's edges and one with the single edge. Right now, this feature is intended for coincident edge selection, not for intersections.

  But generalizing to "point-like" edges as output for intersections should be possible.

  Matthias
• tok

  November 2019

  Ok, thanks! Yes, I think this would make KLayout an even more general geometry library.
• Matthias

  November 2019

  I have created a ticket here: https://github.com/KLayout/klayout/issues/new

  However, "DEdge" is difficult as there is no database unit in the general case. But "Edge" should be possible.

  Matthias