Perimeter

natalie

Hello Everyone,

I recently looked at the area script which I was able to use in KLayout. Now I am trying to find the perimeter of shapes (some shapes even have curves) in KLayout. When I copy and paste the code that was provided in this forum, it doesn't work. I get a lot of errors about 'db' and it doesn't recognize many of the methods such as begin_edge(), etc.

SO I tried making my own code, and I am unsuccessful. I was wondering if someone could take a look at it for me, and let me know where I am going wrong.

Thanks in advance, Natalie

class MenuAction < RBA::Action
def initialize( title, shortcut, &action )
self.title = title
self.shortcut = shortcut
@action = action
end
def triggered
@action.call( self )
end
private
@action
end

$compute_total_perimeter = MenuAction.new( "Compute perimeter of selected shapes", "" ) do

app = RBA::Application.instance
mw = app.main_window

lv = mw.current_view
if lv == nil
raise "No view selected"
end

total_perimeter = 0.0

lv.each_object_selected do |obj|

shape = obj.shape
layout = lv.cellview(obj.cv_index).layout

if shape.is_polygon? || shape.is_box? || shape.is_path?
poly=shape.path
shape.each_point
edge=poly.path_bgnext

while (edge!=poly.path_endext)
total_perimeter+=edge.path_width

end

end



RBA::MessageBox.info("Total points", "Total points of selected object is #{total_perimeter} microns", RBA::MessageBox.b_ok)

end

app = RBA::Application.instance
mw = app.main_window

menu = mw.menu
menu.insert_separator("tools_menu.end", "name")
menu.insert_item("tools_menu.end", "compute_total_perimeter", $compute_total_perimeter)

Matthias

Hi Natalie,

please see me comments in the other forum entry. The problem was that this this discussion was basically about C++ code and you can't mix that with Ruby.

Here is the correct code:

total_perimeter = 0.0

lv.each_object_selected do |obj|

  # TODO: check, whether the selected object is an instance ...
  shape = obj.shape
  if shape.is_polygon? || shape.is_box? || shape.is_path?
    shape.polygon.each_edge { |e| total_perimeter += e.length }
  end

end

Regards,

Matthias

natalie

Thank you so much for your help Matthias!

The code runs and works, but there is one a slight problem. The calculated perimeter is always 1000 times larger than the actual perimeter...

Is it possible that it doesn't know when the final edge is?

Thanks again for all your help, Natalie

natalie

Oh, I was able to fix.

Here is now my corrected code. Thanks again Matthias!

class MenuAction < RBA::Action
def initialize( title, shortcut, &action )
self.title = title
self.shortcut = shortcut
@action = action
end
def triggered
@action.call( self )
end
private
@action
end

$compute_total_perimeter = MenuAction.new( "Compute total perimeter of selected shape", "" ) do

app = RBA::Application.instance
mw = app.main_window

lv = mw.current_view
if lv == nil
raise "No view selected"
end

total_perimeter = 0.0

lv.each_object_selected do |obj|

shape = obj.shape
layout = lv.cellview(obj.cv_index).layout

if shape.is_polygon? || shape.is_box? || shape.is_path?
shape.polygon.each_edge { |e| total_perimeter += e.length*obj.trans.mag*layout.dbu }
end

end

RBA::MessageBox.info("Total perimeter", "Total perimeter of selected object is #{total_perimeter} microns", RBA::MessageBox.b_ok)

end

app = RBA::Application.instance
mw = app.main_window

menu = mw.menu
menu.insert_separator("tools_menu.end", "name")
menu.insert_item("tools_menu.end", "compute_total_perimeter", $compute_total_perimeter)

Matthias

Hi Natalie,

yes you're right, The DBU multiplication is doing the trick and again you're right that you have to take the magnification in the instantiation path into account. I forgot that. Thank you for the hint.

Just to add some final remark: you can optimize the perimeter loop somewhat by doing the multiplication outside the loop. Ruby is not a fast language, so that might be a good idea:

perimeter = 0
shape.polygon.each_edge { |e| perimeter += e.length }
total_perimeter += perimeter * obj.trans.mag * layout.dbu

Regards,

Matthias