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LibreDWG - free implementation of the DWG file format

LibreDWG is a free C library to read and write DWG files. This program is part of the GNU project, released under the aegis of GNU. It is licensed under the terms of the GNU General Public License version 3 (or at you option any later version).

DWG is a file format created in the 70's for the emerging CAD applications. Currently it is the native file format of AutoCAD, a proprietary CAD program developed by AutoDesk.

LibreDWG is a fork from LibDWG due to its usage of Esperanto, which we think is not the best strategy for a free software project which aims to get lots of contributors. LibreDWG is written in English. At the moment our decoder (i.e. reader) is done, just some very advanced R2010+ and pre-R13 entities fail to read and are skipped over. The writer is good enough for R2000. Among the example applications we wrote using LibreDWG is a reader, a writer, a rewriter (i.e. saveas), an initial SVG and Postscript conversion, dxf and json converters, dwggrep to search for text, and dwglayer to print the list of layers. More are in the pipeline. Please contact us if you want to help.

The strings API is utf-8 (wtf8 really, Windows UCS-2 has no surrogate pairs), and encodes to the internal 8-bit or UCS-2 strings, depending on the DWG version.

Sometimes we hang on our IRC channel which is #libredwg at If you don't find us there, please email the package maintainers:

Reini Urban

The now inactive founders and previous maintainers were:

Felipe Corrêa da Silva Sanches Rodrigo Rodrigues da Silva Hardeep Singh Rai

If you are looking for general information about the project, check our website:

== Building and installing the library ==

You need the following dependencies: - Basic development tools (a C99 compiler like gcc/clang, make, autoconf, automake and libtool)


  • gperf to update static hashes for several API's Only needed when you added objects or changed the dwg.spec significantly
  • TeXinfo for building the docs
  • pslib for dwg2ps:
  • pcre2 with 8bit and 16bit libraries for dwggrep regexp support
  • SWIG 1.7+
  • Python 2.7 or 3.x development headers (debian: python-dev; yum: python-devel) and the libxml2 python bindings.
  • Perl 5 for the perl bindings
  • doxygen to generate the reference manual
  • jq to check json validity
  • shellcheck to check shell scripts
  • rpmlint to check the spec validity
  • jinq with some svg11 relaxng to check SVG validity. LaTeXML used to have a broken svg11-basic.rng. If so the zip from is correct. Needs to be installed into /usr/local/share/relaxng/svg11/
  • mapbox/geojsonhint as geojson linter npm install -g @mapbox/geojsonhint
  • geojson-validation as 2nd geojson fallback linter npm install -g geojson-validation
  • valgrind to find leaks and memory bugs
  • timeout to help tests with large or hanging DWG's
  • GNU parallel to speed up special tests (not the moreutils parallel!)
  • picat to find unknown fields, a better prolog.

See INSTALL for generic instructions. Basically, you do:

$ sh ./ (if you checked out the source code from git) $ ./configure [--enable-trace] [--disable-write] [--disable-shared] $ make $ make check $ sudo make install

This builds and installs various files in the "installation dirs": $libdir ($execprefix/lib) -- library files (libredwg.*) $includedir ($prefix/include) -- dwg.h dwgapi.h $libdir/pkgconfig -- libredwg.pc $infodir ($datarootdir/info) --

Use "./configure --help" to see a full list of options you can use to customize the installation dirs. Other options recognized by configure are:


Recommended for packagers and fuzzers. Disables all features
which will not be enabled in official tarball releases. Like support
for pre-R13 DWGs, skipping unstable DWG features, unknown DWG versions
and objects.


Enable runtime tracing (default: no).  When enabled, the environment
variable LIBREDWG_TRACE is consulted on the first decode/encode attempt.
Its value is an integer: 0 (no output) through 9 (full verbosity).
Most tools do support a --verbosity|-v flag instead.


Disable DWG write support (default: no). When enabled, you activate the write
support for the DWG format.
This is an experimental feature. Rewriting most DWG's to the r2000 format
usually works fine, DWG versions since r2004 are not yet supported, and the
API usage is very rough so far.


Disable SWIG bindings for python and perl5.


Disables all in and out modules: DXF, DXFB, JSON, GeoJSON.


Disables the json in and out modules: JSON, GeoJSON.


Disable python bindings and tests.
Related: --enable-python=python3.6
Enforce a specific version.


Activates support for unstable classes. For testing only.


Activates support for GNU gcov, test coverage reporting.


Where to install the perl bindings: vendor,arch,yes,no,site. Default is perl-install=site

== Windows ==

See the following scripts how we build on Windows:

  • build-aux/ cross-compilation recipes
  • build-aux/msys2.bat: msys2 deps
  • .appveyor.yml: windows smoker

We only support C99 compilers and POSIX environments, i.e. cygwin or msys or cross. stdint.h and inttypes.h must be available. Pre-compiled Windows binaries are here:

== Example usage of the library ==

The programs and examples directories contains some application code that uses our lib:

  • dwgread -- A DWG reader supporting various output formats, such as JSON, DXF, DXFB, GeoJSON. Later also YAML, XML/OGR, GPX, SVG, PS.

  • dwgwrite -- A DWG writer supporting various input formats, such as DXF, DXFB, JSON. GeoJSON, YAML, XML/OGR, GPX are under construction.

  • dwgrewrite -- Reads a DWG, writes it back under a different name and optionally under a different version (default r2000), and re-reads it back for confirmation.

  • dwg2dxf -- Converts a DWG to a DXF (ascii or binary, minimal or full), optionally under a different version. About 90% coverage.

  • dxf2dwg -- Converts a ascii or binary DXF to a DWG (r2000 only so far). About 80% coverage.

  • dwglayers -- Prints the list of layers in a DWG. Optionally with --extnames

  • dwggrep -- Searches DWG files for a text string, via regular expressions.

  • dwg2ps -- Opens a DWG file and outputs an PostScript file. This code depends on the PSlib library. On Debian-based systems this is usually available as a package named pslib-dev. This is very limited so far.

  • dwg2SVG -- Opens a DWG file and outputs an SVG (Scalable Vector Graphics) file. SVG is a W3C standard for 2d vector graphics. You can open these files on several free software tools. We recommend Inkscape, a free software vector graphics editor. The dwg2SVG program will not handle 3d content from DWG since SVG only supports 2-dimensional images. Handles only some entities.

  • dwgbmp -- Extracts the bmp thumbnail of a dwg file when it is available.

  • load_dwg -- This is a skeleton code, reading the DWG and adding an entity. Look there if you want to have a quickly glance on how to use the library.

  • dwg2svg2 -- Another example how to use the DWG API, bypassing direct access to the DWG struct.

  • xmlsuite -- an extensive example library to use XML to compare against prepared features is in the test/xmlsuite directory. It also features code to output entities in XML, but does not use the python bindings.

Copyright (C) 2009, 2010, 2015, 2018-2020 Free Software Foundation, Inc.

This library is free software, licensed under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. You should have received a copy of the GNU General Public License along with this program. If not, see

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