Find Length KLayout

find_length.lym

<?xml version="1.0" encoding="utf-8"?>
<klayout-macro>
 <description>Find Resonator Length</description>
 <version/>
 <category>pymacros</category>
 <prolog/>
 <epilog/>
 <doc/>
 <autorun>true</autorun>
 <autorun-early>false</autorun-early>
 <priority>0</priority>
 <shortcut/>
 <show-in-menu>true</show-in-menu>
 <group-name/>
 <menu-path/>
 <interpreter>python</interpreter>
 <dsl-interpreter-name/>
 <text>import pya
import math

app = pya.Application.instance()

view = app.main_window().current_view()
menu = app.main_window().menu()

def find_length():
  selection = pya.Region()
  dbu = []
  for path in view.object_selection:
    dbu.append(view.cellview(path.cv_index).layout().dbu)
    selection.insert(path.shape.polygon)
    
  if selection.is_empty():
    pya.MessageBox.warning('Warning', 'No Selection, select a resonator', pya.MessageBox.Ok)
    return
  
  if any([ unit != dbu[0] for unit in dbu ]):
    pya.MessageBox.warning('Warning', 'Warning: some of the selection is in a layer with a different unit', pya.MessageBox.Ok)
    return
  
  dbu = dbu[0]
  
  selection.merge()
  
  perimeter = dbu * selection.perimeter()
  # area = dbu * dbu * selection.area()
  length = perimeter / 2
  pya.MessageBox.info('Length Estimate', f'Approximate Length: {length}\n\nRemember: this only really works for convex closed loops (if measuring a spiral, subtract the waveguide width)', pya.MessageBox.Ok)
  # Maybe more general formula?
  # length = perimeter / 4 + math.sqrt(perimeter ** 2 / 16 - area)

if __name__ == "__main__":
  if view is not None:
    find_length()
</text>
</klayout-macro>