GLE stands for graphics layout engine. Essentially, it is a scripting language (a kind of programming language) that lets you draw figures, diagrams, and graphs. GLE outputs to graphics file formats such as Encapsulated PostScript (EPS) or Portable Document Format (PDF). The scripting language is very flexible, supporting commands for standard graphics elements and programming constructs.

For example it supports:

• Lines, circles, boxes, arrows, and text.
• Mathematical functions, such as, sin(), cos(), log(), exp(), etc.
• For-next loops, subroutines, variables, if-then-else.
• A graph module for drawing graphs of data and functions.
• Advanced graphics commands like paths, clipping, and rotation.
• Inclusion of bitmap and PostScript files.
• Inclusion of other GLE files thus allowing libraries.

The original version of GLE was developed by Chris Pugmire and included support for various types of output devices. The most useful output device (for me at least) is PostScript. It is very handy for people who use LaTeX, since it allows creation of excellent looking EPS and PDF files that can be directly included into the LaTeX document. In addition, it included an editor, previewer and other utilities like a simple spreadsheet.

For example:

size 10 10
begin graph
    data "data.dat"
    d1 marker fcircle color red
    title  "This is the graph title"
    xtitle "This is the x axis title"
    ytitle "This is the y axis title"
end graph

See the documentation for more information on drawing graphs.