The goal of the Lensfun library is to provide a open source database of photographic lenses and their characteristics. In the past there was a effort in this direction (see https://www.epaperpress.com/ptlens/), but then author decided to take the commercial route and the database froze at the last public stage. This database was used as the basement on which Lensfun database grew, thanks to PTLens author which gave his permission for this, while the code was totally rewritten from scratch (and the database was converted to a totally new, XML-based format).

The Lensfun library not only provides a way to read the database and search for specific things in it, but also provides a set of algorithms for correcting images based on detailed knowledge of lens properties. Right now Lensfun is designed to correct distortion, transversal (also known as lateral) chromatic aberrations, and vignetting.

The interface is defined both using C++ style and plain C. The C interface is a wrapper around the C++ classes.

GitHub Project: https://github.com/lensfun/lensfun GitHub Page: https://lensfun.github.io/

The libraries which are part of this package are licensed under the terms of the GNU Lesser General Public License, version 3. Libraries are located under the subdirectory libs/ of the source package. A copy of the license is available in the file COPYING.LESSER which can be found in the source archive. You can read it here: https://www.gnu.org/licenses/lgpl-3.0.html

The documentation files, including those autogenerated with Doxygen, are covered as well by GNU Lesser General Public License, version 3.

Applications which are part of this package are licensed under the terms of the GNU General Public License, version 3. Applications are located under the apps/ subdirectory of the source package. A copy of the license can be found in the file COPYING which can be found in the source archive. You can read it here: https://www.gnu.org/licenses/gpl-3.0.html

Test programs and tools are put into public domain, unless explicitly specified otherwise in the header of the source files. Test programs are located under the tests/ subdirectory, and tools are located in tools/.

The lens database is licensed under the Creative Commons Attribution-Share Alike 3.0 license (CC BY-SA 3.0). The database is located under the data/ subdirectory of the source package and a copy of the license is available in the file data/COPYING.CC_BY-SA_3.0 which can be found in the source archive. You can read it here: https://creativecommons.org/licenses/by-sa/3.0/

The build system is based on CMake (https://www.cmake.org/). In order to successfully configure and build the project the following tools are more or less required:

• CMake
• Doxygen in order to generate the library documentation.
• GLib > 2.26 which is used for low-level I/O and XML parsing.
• GLib > 2.40 to build the unit tests with the GLib test framework.
• libpng is required to build and run the example implementation.
• xmllint to test the database XML validity

First enter the Lensfun root folder and create a build directory.

cd lensfun
mkdir build

Enter the build directory and run CMake to configure your sources and create the build files

cd build
cmake ../

Run make/make install as usual

make
make install

After that, you may want to use ldconfig to add the necessary symlinks so that programs can find and use Lensfun.

The following CMake options can be set (defaults are upper case):

-DCMAKE_BUILD_TYPE=DEBUG|Release        select debug or release build mode
-DINSTALL_HELPER_SCRIPTS=off|ON         install various helper scripts
-DCMAKE_INSTALL_PREFIX=/USR/LOCAL       install prefix

-DBUILD_STATIC=OFF|on       build static or shared lib
-DBUILD_TESTS=OFF|on        build also the test programs
-DBUILD_LENSTOOL=OFF|on     build Lensfun reference implementation
-DBUILD_FOR_SSE=off|ON      build with SSE optimisation
-DBUILD_FOR_SSE2=off|ON     build with SSE2 optimisaiton
-DBUILD_DOC=OFF|on          build documentation

If you want to have more detailed output when running 'make' you can simply add 'VERBOSE=1' to the make command line.

You can also build packages with cmake:

Add -DCPACK_BINARY_DEB:BOOL=ON or -DCPACK_BINARY_RPM:BOOL=ON to the
command line and then "make package". (But this is not extensively tested.)

Please note that running cmake again does NOT reset all options to default or reconfigure all variables. To restart with a clean configuration delete all files in your cmake_build folder.

If you prefer setting the configuration with a GUI or want to get an extensive overview of all available settings and cache values run cmake-gui.

The end-user documentation for the library can be built by issuing the command:

make docs

Also you can read it online at any time by pointing your browser to:

https://lensfun.github.io/manual/latest

The documentation on the site is updated every night from Git, so it always contains the latest info on the library.

Here goes a full list of people who have contributed to this library:

CODE:

Andrew Zabolotny [email protected]

LENS DATA:

Tom Niemann: original open-source ptlens database.

THANKS:

Pablo d'Angelo for the idea of a open-source lens database.

The whole PanoTools team, for all math and knowledge I have borrowed from PanoTools:

Helmut Dersch - The father of most (all?) open-source panorama creation tools. Daniel M. German Kevin Kratzke Rik Littlefield Fulvio Senore Jim Watters Thomas Rauscher Pablo d'Angelo (thanks once more :) Bret McKee Robert Platt

Also I would like to thank the people that made valuable contributions to Lensfun:

Niels Kristian Bech Jensen Pascal de Bruijn Thomas Modes Torsten Bronger

And of course great thanks to all the people sending profiles for the database.