GWCAD!
Free Open Source Simple 2D Cad Program for Linux!
(and windows, osx, android, ios but I wouldn't want to try to use it on those last two..)
If you don't have Allegro, you can compile it from above link, or if you have ubuntu,
you may be able to install it with the instructions here.
The latest Allegro source may be Here - use the HTTPS clone URL if you're using git,
or click the "Download ZIP" button on the right side of the page.
Some time before perhaps 2002 I started learning C and started this project.
It was to be a simple 2D cad program for designing simple printed circuit boards.
It progressed extremely slowly, and then underwent a nearly complete rewrite a couple years ago
and now in 2015 has reached a very minimally usable state so today (July 26th, 2015) I have
released it!
At times, it was also a raster/vector moving map display system, but that went away
during the rewrite a couple years ago. I would like to add that feature back in, simple GIS functionality.
The file format is a simple human readable format, and so far it supports arcs, points,
lines, linestrings, polygons, and filled polygons with multiple cutouts/holes,
although it has no way yet to add cutouts to filled polygons.
Lots of functionality is not supported relating to printing and stuff, however it can
print out lines and arcs as 2D G-Code tool paths. So far that's the only format supported for exporting/printing.
