Module: Gdsii

Defined in:: lib/gdsii.rb,
lib/gdsii/bnf.rb,
lib/gdsii/box.rb,
lib/gdsii/aref.rb,
lib/gdsii/node.rb,
lib/gdsii/path.rb,
lib/gdsii/sref.rb,
lib/gdsii/text.rb,
lib/gdsii/group.rb,
lib/gdsii/mixins.rb,
lib/gdsii/strans.rb,
lib/gdsii/library.rb,
lib/gdsii/boundary.rb,
lib/gdsii/property.rb,
lib/gdsii/structure.rb,
lib/gdsii/record/datatypes/data.rb,
lib/gdsii/record/datatypes/int2.rb,
lib/gdsii/record/datatypes/int4.rb,
lib/gdsii/record/datatypes/ascii.rb,
lib/gdsii/record/datatypes/real4.rb,
lib/gdsii/record/datatypes/real8.rb,
lib/gdsii/record/datatypes/nodata.rb,
lib/gdsii/record/datatypes/bitarray.rb

Overview

There are two approaches to interacting with a GDSII file using this module:

At the record level (low-level)
At the record group level (high-level)

Approach #1

(See Record class for details)

Interaction at the record level is intended for streamlined file processing where the author has a good knowledge of the GDSII structure. A typical usage might be to streamline changes to a GDSII file such as changing bus bit characters on a node name from <> to [] format (see the samples directory of this library installation for an example). Here is a simple way to dump the all strings in a GDSII file using the Record class:

require 'gdsii'

# Note: 'rb' is required for DOS/Windows compatibility
File.open('mydesign.gds', 'rb') do |file|
  Gds::Record.read_each(file) do |record|
    puts record.data[0] if record.is_string?
  end
end

Approach #2

(See Group, Library, Structure, Element, Boundary, Path, Text, SRef, ARef, Node, and Box classes for details)

The second approach offers a high-level interface to the GDSII format which might be ideal in cases where the author may not be familiar with the details of the GDSII format. This example will write a small transistor cell:

require 'gdsii'

Gdsii::Library.new('MYLIB.DB') do |lib|

  Gdsii::Structure.new('trans') do |struct|

    # Diffusion layer
    struct.add Gdsii::Boundary.new(1, 0, [-2000,0, -2000,4000, 2000,4000, 2000,0, -2000,0])

    # Gate layer... add a property labling as "gate"
    Gdsii::Path.new(2, 0, 0, 800, [0,-600, 0,4600]) do |path|
      path.add Gdsii::Property.new(1, 'gate')
      struct.add path
    end

    # Add this structure to the library
    lib.add struct

  end

  # Write the library to a file
  lib.write('trans.gds')

end

Important notes

Look at inherited and mixed-in methods

The high-level classes in this GDSII library rely heavily upon inheritance and mixed-in modules to reduce code. When reviewing documentation, be sure to be aware of methods defined implicitly through class inheritance and through Module#include and Module#extend.

Use ‘b’ during R/W of files

Be sure to always use the ‘b’ read/write attribute when reading and writing GDSII files to ensure that read/write happens properly on DOS/Windows systems. For example (see IO#open for more details):

inf = File.open('mydesign.gds', 'rb')
outf = File.open('mydesign.gds', 'wb')

Improving performance

The low-level GDSII methods will offer significantly better GDSII read/write performance as compared to the high-level methods. For most streamlined manipulations of GDSII files, the low-level methods are probably the best option. For smaller GDSII files or when code re-use/readability is important, then the performance hit with the high-level methods may not be a concern.

Here are some benchmarks using both low and high level methods to read and immediately write a GDSII file:

GDSII file size: 7 MB
WinXP machine: Intel® Pentium® M (Centrino) 1.6 Ghz @ 1 GB RAM
Linux machine (SuSE): 2x Intel® Pentium® 4 3.4 Ghz @ 1 GB RAM
```
 Linux      WinXP
-------    -------
```

High-level methods:      8m 45s    11m 23s
Low-level methods:       0m 45s     1m 29s

Defined Under Namespace

Modules: Access, Read, RecData Classes: ARef, BnfItem, BnfRecords, BnfSpec, Boundary, Box, Group, Library, Node, Path, Properties, Property, SRef, Strans, Structure, Structures, Text

Constant Summary collapse

DEF_LIB_VERSION =

DEF_LIB_UNITS =

[0.001,1.0e-09]