The Madd Games Terminal Library (libmaddterm) is a library for emulating the rxvt terminal and optionally the xterm. It has no rendering and input support, which means you can implement that yourself. You can feed data (including escape sequences etc) to this terminal directly, or, if you are on a UNIX system, start a process attached to the virtual terminal.
We are superior to libvterm because we support xterm control sequences and make no references to libncurses! All hail Madd Games!