jimfoltz / ruby-dxf-reader

Parse DXF files into Ruby objects

ruby-dxf-reader

Reads an ASCII DXF file and returns it as a Ruby Hash object. The Sections and Entities are converted into the basic Ruby objects of Hash, Array, Float, Fixnum, and String. This library is meant to be a building-block for more advanced DXF processing using Ruby.

The top-level data structure is a Hash of containers representing SECTIONS of the .dxf file. Currently supported sections are the HEADER, BLOCKS, and ENTITIES sections. The top-level Hash looks as follows:

{"HEADER"=>{...}, "BLOCKS"=>[...], "ENTITIES"=>[...]}

The HEADER Section

The HEADER section is a Ruby Hash object. Reading the HEADER variables can be done as follows:

require 'dxf2ruby'
dxf = JF::Dxf2Ruby.parse("file.dxf")
header = dxf['HEADER']
acad_version = header['$ACADVER'][1] # ==> "AC1015"

###The BLOCKS Section

The BLOCKS section is a Ruby Array of Hash objects where each Hash object represents a DXF Entity.

The ENTITIES Section

The ENTITIES section is a Ruby Array of Hash Objects. Each Hash object represents a DXF Entity.

Entities

Acad Entities are returned as Ruby Hash objects. A typical entity may look similar to the following Hash, which represents an Acad LINE:

{0=>"LINE", 5=>"25", 100=>["AcDbEntity", "AcDbLine"], 8=>"0",
6=>"CONTINUOUS", 62=>7, 10=>-4.672884, 20=>-0.816414, 30=>0.0,
11=>-4.672884, 21=>-0.27178, 31=>0.0}

The Hash keys correspond to the 'group code' of the Entity.

Example Use

require 'dxf2ruby'
dxf = JF::Dxf2Ruby.parse("file.dxf")
acad_version =  dxf['HEADER']['$ACADVER']
dxf['ENTITIES'].each do |entity|
  draw(entity)
end

def draw(entity)
 case entity[0]
 when "POINT"
  draw_point(entity)
 when "LINE"
  draw_line(entity)
  end
 end

Dxf2RUby may also be used on a command line to inspect a DXF file:

   $ dxf2ruby file.dxf

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About DXF (Notes from AutoCAD)

DXF Objects have no graphical representation. (aka nongraphical objects)

DXF Entities are graphical objects.

Accommodating DXF files from future releases of AutoCAD® will be easier if you write your DXF processing program in a table-driven way, ignore undefined group codes, and make no assumptions about the order of group codes in an entity. With each new AutoCAD release, new group codes will be added to entities to accommodate additional features.