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Hello,

I am super new to KLayout and started becasue of work.
I`ve gotten a lot of nice tips from this forum. So appriciate it

I have a question how to popup alert message when it is not available input.

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class SquarePCell < PCellDeclarationHelper

include RBA

def initialize

  # Important: initialize the super class
  super

  # declare the parameters
  param(:l1, TypeLayer, "Layer1", :default => LayerInfo::new(1, 0))
  param(:l2, TypeLayer, "Layer2", :default => LayerInfo::new(1, 0))
  param(:l3, TypeLayer, "Layer3", :default => LayerInfo::new(1, 0))
  param(:l4, TypeLayer, "Layer4", :default => LayerInfo::new(1, 0))
  param(:w, TypeDouble, "Width of PCell", :default => 400, :unit => "µm")   
  param(:g, TypeDouble, "Gap between upper & lower PCell", :default => 800, :unit => "µm")
  param(:g_oi, TypeDouble, "Gap between outer & inner square", :default => 100, :unit => "µm")
  param(:h_1st, TypeDouble, "Hight of 1st square", :default => 800, :unit => "µm")
  param(:h_2nd, TypeDouble, "Hight of 2nd square", :default => 800, :unit => "µm")
  param(:p_2nd, TypeDouble, "Position of 2nd square", :default => 50, :unit => "%")
  param(:hight, TypeInt, "Total hight", :default => 20000)
  param(:width, TypeInt, "Total width", :default => 100000)
end

def display_text_impl
  # Provide a descriptive text for the cell
  "SquarePCell"
end

def produce_impl

  # This is the main part of the implementation: create the layout

  # compute the ray parts and produce the polygons      
  app = RBA::Application.instance
  mw = app.main_window
  lv = mw.current_view
  #new_layout = mw.create_layout(2)

  raise "No view selected" if lv.nil?      
  dbu = lv.active_cellview.layout.dbu



  w_3rd = w - 2*g_oi
  h_3rd = h_1st*p_2nd/100.0 - 2*g_oi

  #Code: origin at bottom left chip corner
  #Choose manual coordinate origin 
  x0 = 0 
  y0 = 0     
  g_1st_c = 0
  g_1st_f = 0
  g_2nd_c = 0      
  g_2nd_f = 0              
  g_3rd_c = 0
  g_3rd_f = 0
  h_whole = 0

  col = width.div(w) # .div returns integer value by floor 
  row = 0 # it will initiate in the for loop 
  i = 0 # for do loop because total hight is calculated after the first run ( get hight of one PCell)
  loop do # x axis
    col.times do |j| # y axis
        # lb_u => Left Below point  of upper PCell  //  ru_u => Right Upper point of upper PCell
        # lu_l => Left Upper point of Lower PCell   //  rb_l => Right Below point of Lower PCell

        # Upper PCell
        x_1st_lb_u = x0 + j * w
        y_1st_lb_u = y0 + g/2 + i*h_whole
        x_1st_ru_u = x_1st_lb_u + w
        y_1st_ru_u = y_1st_lb_u + h_1st 

        x_2nd_lb_u = x_1st_lb_u
        y_2nd_lb_u = y_1st_lb_u + h_1st*p_2nd/100.0
        x_2nd_ru_u = x_2nd_lb_u + w
        y_2nd_ru_u = y_2nd_lb_u + h_2nd

        x_3rd_lb_u = x_1st_lb_u + g_oi
        y_3rd_lb_u = y_1st_lb_u + g_oi
        x_3rd_ru_u = x_3rd_lb_u + w_3rd
        y_3rd_ru_u = y_3rd_lb_u + h_3rd

        raise "2nd position should be larger then now!\n" if y_3rd_ru_u - y_3rd_lb_u < 0

        # Calculating gap with respect to 1st/2nd/3rd boxes.
        # _c is closer bound gap  //  _f is further bound gap
        if i == 0 and j == 0
          g_1st_c = 2 * y_1st_lb_u
          g_1st_f = 2 * y_1st_ru_u

          g_2nd_c = 2 * y_2nd_lb_u
          g_2nd_f = 2 * y_2nd_ru_u

          g_3rd_c = 2 * y_3rd_lb_u
          g_3rd_f = 2 * y_3rd_ru_u

          h_whole = 2 * y_2nd_ru_u
          row = hight.div(h_whole)
        end

        # Lower PCell
        x_1st_lu_l = x_1st_lb_u
        y_1st_lu_l = y_1st_lb_u - g_1st_c
        x_1st_rb_l = x_1st_ru_u
        y_1st_rb_l = y_1st_ru_u - g_1st_f

        x_2nd_lu_l = x_2nd_lb_u
        y_2nd_lu_l = y_2nd_lb_u - g_2nd_c
        x_2nd_rb_l = x_2nd_ru_u
        y_2nd_rb_l = y_2nd_ru_u - g_2nd_f

        x_3rd_lu_l = x_3rd_lb_u
        y_3rd_lu_l = y_3rd_lb_u - g_3rd_c
        x_3rd_rb_l = x_3rd_ru_u
        y_3rd_rb_l = y_3rd_ru_u - g_3rd_f

        # Wrapping PCell
        x_4th_lb = x_1st_lb_u
        x_4th_ru = x_1st_lb_u + w
        y_4th_lb = y_2nd_rb_l
        y_4th_ru = y_2nd_ru_u


        cell.shapes(l1_layer).insert(RBA::Box::new(x_1st_lb_u/dbu, y_1st_lb_u/dbu, x_1st_rb_l/dbu, y_1st_ru_u/dbu))
        cell.shapes(l2_layer).insert(RBA::Box::new(x_2nd_lb_u/dbu, y_2nd_lb_u/dbu, x_2nd_rb_l/dbu, y_2nd_ru_u/dbu))
        cell.shapes(l3_layer).insert(RBA::Box::new(x_3rd_lb_u/dbu, y_3rd_lb_u/dbu, x_3rd_rb_l/dbu, y_3rd_ru_u/dbu))

        cell.shapes(l1_layer).insert(RBA::Box::new(x_1st_lu_l/dbu, y_1st_lu_l/dbu, x_1st_rb_l/dbu, y_1st_rb_l/dbu))
        cell.shapes(l2_layer).insert(RBA::Box::new(x_2nd_lu_l/dbu, y_2nd_lu_l/dbu, x_2nd_rb_l/dbu, y_2nd_rb_l/dbu))
        cell.shapes(l3_layer).insert(RBA::Box::new(x_3rd_lu_l/dbu, y_3rd_lu_l/dbu, x_3rd_rb_l/dbu, y_3rd_rb_l/dbu))

        cell.shapes(l4_layer).insert(RBA::Box::new(x_4th_lb/dbu, y_4th_lb/dbu, x_4th_ru/dbu, y_4th_ru/dbu))       
    end

    i += 1        
    break if i == row

  end
end

end
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In this code, if you see raise part, I want to pop up a message window to user to inform it is not available.
How can I change the code?