“In previous articles (HERE and HERE), we have talked about the RGB LED matrix panel as well as the RGB Matrix HAT which is the hardware interface between the LED panel and the Raspberry Pi. Today we will cover how to draw simple graphics on the LED panel. Once the RGB Matrix HAT is connected to the Raspberry Pi and to the RGB LED matrix panel, you can start your Raspberry Pi and play with GeeXLab. From version 0.13, GeeXLab comes with built-in functions in Lua and Python to drive RGB LED matrix panels. For this article, I use Raspbian Jessie with Pixel desktop as well as GeeXLab 0.13.0 with OpenGL 2.1 support for Raspberry Pi (you can download this version from THIS PAGE). There is a second version of GeeXLab with OpenGL ES support but I prefer the OpenGL 2.1 version of GeeXLab because 3D accelerated windows are supported using X11/GLX.”