EGGX/ProCALL --- X11 Graphics Library
EGGX/ProCALL is an X11 graphics library for C and FORTRAN created to achieve extreme simplicity. It's available also on C++. You can enjoy 2D graphics easily on the X Window System by using good old BASIC style drawing functions. Out of our desire to deliver simple usability and the fun that we have had when using BASIC in the age of the 8-bit machine to whomever starts to learn programming, we have created this library mainly for basic programming education. Since it ensures enough drawing speed on 10-year-old PCs, it can deal tasks like creating an animation or creating a simple game. Furthermore, this library provides a powerful solution to the visualization of numerical calculation. What sets this library from other common visualization tools is that it can call drawing functions (subroutines) for X11 from a calculation code directly. Generally, complicated implementation is necessary to grasp the progress of the calculation in time-consuming simulation. However, you can provide a link using this library without any worries because it is an easy-to-implement, very lightweight and compact library that does not consume a lot of memory. EGGX/ProCALL uses only Xlib for X11 libraries. Therefore, it can be installed easily in any UNIX environment (even Cygwin).
Official Web site: https://www.ir.isas.jaxa.jp/~cyamauch/eggx_procall/