rplot

https://github.com/pioz/rplot

GNU libplot is a free function library for drawing two-dimensional vector graphics. It can produce smooth, double-buffered animations for the X Window System, and can export files in many graphics file formats. It is `device-independent' in the sense that its API (application programming interface) is to a large extent independent of the display type or output format. Rplot is a C extension for Ruby of GNU libplot.