PLplot is a cross-platform, scientific graphics plotting library that supports math symbols and human languages (via UTF-8 user input strings); plot capabilities for multiple non-interactive plot file formats and in multiple interactive environments; and bindings for multiple computer languages.
...It allows command line applications written in ObjC, C, FORTRAN, Lisp, Perl or Python to display vector graphics, text and images using a simple API. Adapters for gnuplot, PGPLOT, and PLplot exists as well.