There are 3 repositories under hpgl-plotters topic.
A curated list of code and resources for computer-controlled drawing machines and other visual art robots.
Pen Plotter Webserver for RPI0
Pen plotter utilities and GUI for image conversion, SVG optimization, HPGL conversion and headless print
Pen Plotter Webserver for Raspberry .Pi. This is a modified fork for use with the Pi Plot shield.