There are 4 repositories under hpgl topic.
A curated list of code and resources for computer-controlled drawing machines and other visual art robots.
A GCode sender (not only for lasers or plotters) for up to two GRBL controller. SVG, DXF, HPGL import. 6 axis DRO.
DrawingBotV3 is a software for converting images into vector art
Vector graphics software to generate HPGL output to drive a plotter
Pen Plotter Webserver for RPI0
Generate DM/PL command instructions for hardware plotters
This device translates X-Y analog plotter output into a stream of HP-GL commands to a file. (Hewlett-Packard Graphics Language, http://en.wikipedia.org/wiki/HP-GL). You can replace your mechanical pen plotter with a Windows-based software plotter, such as SPLOT (http://www.swplot.com/splot.htm).
Plotter Controller for XY41xx
Pen plotter utilities and GUI for image conversion, SVG optimization, HPGL conversion and headless print
How to plot .svg files on the USCutter MH871-MK2. For Golan's Drawing with Machines course.
Pen Plotter Webserver for Raspberry .Pi. This is a modified fork for use with the Pi Plot shield.
HPGL to LinuxCNC GCode converter with GUI written in Java
Offline Tool to View GCODE/HPGL Files https://straight-coding.github.io/gcode-hpgl-viewer/
HPGL Language Support for VSCode
Reverse print server for devices sending HPGL files or similar plots via serial