Did you even know it at the time and if so why did you decide not to use it? I always thought libtcod was THE way to go for fancy ascii games. I would be very interested in your opinion on this.
I actually contributed a bit to libtcod back when it was in active development :D
The roguelike I worked on before Cogmind was originally written to work with libtcod's frontend, but I wanted to do a few unorthodox things and rather than continually patch up libtcod decided to build my own frontend from scratch. that bit was all I was using from libtcod as I already had my own game library and roguelike engine at the time. My version supports mixed font sizes out of the box and is written in C++ rather than C.
The roguelike I worked on before Cogmind was originally written to work with libtcod's frontend, but I wanted to do a few unorthodox things and rather than continually patch up libtcod decided to build my own frontend from scratch. that bit was all I was using from libtcod as I already had my own game library and roguelike engine at the time. My version supports mixed font sizes out of the box and is written in C++ rather than C.