Now MathGL has more than 35000 lines of code, more than 55 general types of graphics for 1d, 2d and 3d data arrays, including special ones for chemical and statistical graphics. It can export graphics to raster and vector (EPS or SVG) formats. It has Qt, FLTK, OpenGL interfaces and can be used even from console programs. It has functions for data processing and script MGL language for simplification of data plotting. Also it has several types of transparency and smoothed lightning, vector fonts and TeX-like symbol parsing, arbitrary curvilinear coordinate system and many over useful things. It can be used from code written on C++/C/Fortran/Python/Octave and many other languages. Finally it is platform independent and free (under GPL v.2.0 license).
There is a forum where you can ask a question or suggest an improvement. However the MathGL group is preferable for quicker answer.
For subscribing to MathGL group you can use form below
About LGPL and GPL licenses.
Generally, MathGL is GPL library. However, you can use LGPL license for MathGL core and widgets if you don’t use SWIG-based interfaces and disable GSL features. This can be done by using
lgpl option at build time. According this, I’ve added the LGPL win32 binaries into Download page.
There is detailed news list. Sourceforge project page here.