Not quite: Dwarf Fortress has always used OpenGL (http://www.bay12forums.com/smf/index.php?topic=28841.0 http://www.bay12forums.com/smf/index.php?topic=28841.0)

Not quite: Dwarf Fortress has always used OpenGL (http://www.bay12forums.com/smf/index.php?topic=28841.0 http://www.bay12forums.com/smf/index.php?topic=28841.0) to render tiles that just happen to be ASCII characters onto the screen. The fan effort was to port it to SDL, making it much more efficient.