I am happy that, almost 30 years years after the very first versions
of GCLC and with many related tools that appeared in the meanwhile,
there is still a steady and wide need for the tool GCLC.
With thousands of GCLC users worldwide, with many books, journal articles,
and theses illustrated with the help of GCLC, and with many courses
on different levels that are taught using GCLC, I am encouraged
to keep the project GCLC active.
After turning opensource in 2020, in March 2024 it is time
to announce one great novelty  webbased version of GCLC,
a contribution by Nikola Ubavić!
Please find the links to the source code, to current versions
of executables, and to the webbased version in the Downloads
section.
Predrag Janičić [home page]
March 2024


GCLC (from "Geometry Constructions > LaTeX
Converter") is a tool for visualizing geometry, and for producing mathematical
illustrations.
Its main purposes are:
 producing digital mathematical illustrations of high quality;
 use in teaching geometry;
 use in studying geometry with the help of automated theorem provers.
The basic idea behind GCLC is that constructions are formal procedures,
rather than drawings. Thus, in GCLC, producing mathematical illustrations
is based on "describing figures" rather than on "drawing figures".
Created figures, of course, can be displayed and can be exported
to LaTeX and other formats.
Although GCLC was initially built as a tool for producing LaTeX
figures from descriptions of geometric constructions, now it is much
more than that. It provides easytouse support for many isometric
transformations, conics, parametric curves, dealing with expressions,
flow control, automated theorem proving, etc.
There versions for Windows and for Linux.
There are command line versions and versions with graphical
user interfaces (that provide a range of additional functionalities).
The very first version of GCLC was written in Nov 1995. GCLC had its first
public release in 1996, and several releases since then. It has thousands
of users wordwide and it has been used for producing digital illustrations
for a number of books, journal articles, theses, and in a number of highschool
and university courses worldwide.

 Freely available;
 Support for a range of elementary and compound constructions,
and isometric transformations;
 Support for symbolic expressions, second order curves, parametric
curves, flow control, userdefined functions, etc;
 Userfriendly interface, interactive work, animations, tracing
points, "watch window" ("geometry calculator"), and other tools;
 Support for drawing trees and graphs;
 Builtin automated theorem provers, capable of proving many
complex theorems;
 Simple, easy to use, small in size;
 Export of high quality figures into LaTeX (simple LaTeX format,
PSTricks format, TikZ format), EPS (Encapsualted PostScript), SVG
(Scalable Vector Graphics), bitmap, PNG, JPG format;
 Command line and version with graphical user interface both for
Windows and Linux;
 Import from JavaView JVX format.

Open source (git repository with source code and prebuilt executables for Linux and Windows, available since Dec 5, 2020):
Current release (command line version (gclc), GUI version (gclcgui), manual, sample files, etc. (current version February 19, 2024):
Webversion of GCLC
GCLC Manual
The original address of this page is:
www.matf.bg.ac.rs/~predrag.janicic/gclc (mirrored versions are not always uptodate)
GCLC is available also from EMIS (The European Mathematical Information Service) servers:
http://www.emis.de/misc/software/gclc/.

GCLC is being developed by Predrag
Janičić (Faculty of Mathematics, University of Belgrade) and, in some parts,
by Predrag Janičić and his coauthors:

Ivan Trajković (University of Belgrade, Serbia)  coauthor of the
graphical user interface for the Windows version WinGCLC (2003);

Nikola Ubavić (University of Belgrade, Serbia)  author of the
webbased version of GCLC (2024);

Pedro Quaresma (University of Coimbra, Portugal) 
coauthor of the theorem prover based on the area method;

Goran Predović (University of Belgrade, Serbia)  the main author of
the theorem provers based on the Wu's methods and on the
Groebner bases method;

Luka Tomašević (University of Belgrade, Serbia) 
the main author of the support for graph drawing;

Konrad Polthier and Klaus Hildebrandt (Technical University,
Berlin, Germany)  coauthors of the JavaView to GCLC converter).

Pedro Quaresma (University of Coimbra,
Portugal), Jelena Tomašević (University of Belgrade, Serbia), Milena
VujoševićJaničić (University of Belgrade, Serbia)  coauthors of the support for
XML.

 If you use GCLC package, please let me know by sending an email to
(Predrag Janicic);
I will put you on the GCLC mailing list and inform you about new releases of GCLC.
 Please send me your comments and suggestions to
. Your
feedback would be very much appreciated and would help in improving the
future releases of GCLC.
 If you used GCLC for producing figures for your
book or a paper, I would be happy to hear about that.
 Please send me your GCLC gems and I will put them on this page.


This software is protected by the Creative Commons licence CC BYND:
AttributionNoDerivatives 4.0 International.
This license allows for redistribution, commercial and noncommercial,
as long as it is passed along unchanged and in whole, with credit to the author.
 You may install and run this untouched software without any restrictions.
 All output of this software is your property. You are free to use it in
teaching, studying, research, and in producing digital illustrations.
 THIS SOFTWARE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 (c) Predrag Janicic 19952024
