How to mimic oddPolygon in Python to check for Self-Intersecting Polygons

Comments

• Matthias

  June 19 edited June 19

  HI @aarush,

  Most DRC functions are basically method calls to "Region", "Edges", "EdgePairs" or "Texts" objects.

  In case of "odd_polygon", the method call is "strange_polygon_check" (see here: https://www.klayout.de/doc-qt5/code/class_Region.html#k_293).

  To mimic this check, construct a "Region" object with the layer you like to investigate and execute "strange_polygon_check".

  Matthias
• aarush

  June 24

  So then does something like this work? Or does it iterate over the layers wrong?

      for cell in layout.each_cell():
          for idx in layout.layer_indexes():
              itr    = layout.begin_shapes(cell, idx)
              region = pya.Region(itr)
  
              region.merged_semantics = False
              strange = region.strange_polygon_check()
              strange.merged_semantics = False
  
              if not strange.is_empty():
                  info  = layout.get_info(idx)
                  count = strange.count()
                  issues.append(
                      f"In '{cell.name}' (L={info.layer},DT={info.datatype}): "
                      f"{count} self-intersecting piece(s)"
                  )
  

  Thank you for all the help,
  Aarush
• Matthias

  June 28

  No, that is wrong.

  A region is already a full layer - you must not iterate over the cells.
  You will need to start from a top cell instead.

  This should work better:

          cell = layout.top_cell()
          for idx in layout.layer_indexes():
              itr    = layout.begin_shapes(cell, idx)
              region = pya.Region(itr)
  ...
  

  Matthias
• aarush

  June 30

  Thank you Matthias, this is now giving me the same output as the Klayout App!!!!

  Best,
  Aarush