tgl was written a long time ago and was originally in C on Linux. It's a scripted graphics
"language", although it's more of a file of commands than a language. It can do all of the
usual things like load an image file, draw lines, circles and text on it and save it back
tgl is almost completely superseded by
except for a few whizzy commands which I love and use all the time like quadtoquad (which
copies the pixels inside a source quadrilateral to a destination quadrilateral.) Just about
anything you want to do, such as scaling, rotating, shearing, etc can be all boiled down to
a single quadtoquad.
tgl is currently being upgraded with lua script for no good reason other than I like to,
because really, I should be using ImageMagick too.