GRX 3 is a graphics library for simple graphics displays. It also includes keyboard, mouse, joystick and touchscreen input support.

It is developed and maintained by ev3dev.org for use with LEGO MINDSTORMS EV3. It also works great with other displays like Adafruit's PiTFT displays.

Why revive an old graphics library instead of using a "modern" library like SDL?

• Other libraries do not handle 1-bit-per-pixel displays (at least not very well). LEGO MINDSTORMS EV3 has a monochrome display, so this is a necessity.
• Other libraries rely on floating point heavily. GRX 3 uses integers mostly. This is important for performance because LEGO MINDSTORMS EV3 does not have a hardware floating point processor.

Why use GLib?

• Using GLib allows other programming languages to use this library with minimal effort using GObject Introspection.

What OSes does it run on?

• Currently, it runs on Linux and macOS.

On the web:

• Docs: http://docs.ev3dev.org/projects/grx/
• Bugs/Questions: https://github.com/ev3dev/grx/issues/
• Wiki: https://github.com/ev3dev/grx/wiki/

Source code directories:

addons/     Last remains of some code from GRX 2.x - not used (but might be useful)
bindings/   Bindings for other programming languages
cmake/      Some CMake modules (this is a git submodule)
data/       Various data files
doc/        Documentation
docker/     Dockerfiles for cross-compiling
example/    Examples of how to use GRX 3
include/    Public header files
plugins/    Pluggable components, such as video drivers
scripts/    Scripts used for development
src/        The main library source code
test/       Old demo/test program from GRX 2.x
tools/      Utility programs

• See copying.grx for details!
• The library itself is LGPL.
• The tools and examples are GPL.

GRX was originally written in the 1990s by Csaba Biegl for DJ Delorie's DOS port of the GCC compiler.

GRX 2.x was actively maintained until about 2012 and was ported to many different platforms.