Button is a Fortran libray created and developed by Nicolás Cardiel
<cardiel@ucm.es> as part of his PhD work (carried out under the supervision of
J. Gorgas) with the aim of using graphical buttons with PGPLOT. The code was
imitially developed in Fortran 77, although some minor changes have
been introduced (January 2023) to compile it as Fortran 90 code (without trying
to make full use of the advantages of Fortran 90).

This code is free software; you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation; either version 2 of the License, or (at your option) any later
version.

Maintainer: Nicolás Cardiel, cardiel@ucm.es
Webpage (documentation): http://button.readthedocs.io/en/latest/
Webpage (source): /~https://github.com/nicocardiel/button