libmabuff is a simple C++ TUI library for Linux. It is based on customized termbox (github.com/nsf/termbox). It might be called an 'ncurses alternative', however, it doesn't provide such functionality. On the other hand, it's much easier to learn and use! Its base elements are Zones of text. You can do some neat "graphic" effects with them, e.g. make borders automatically or adopt color from a zone below (yes, zones are layerable).
It's still in active development, however, it can be used for writing TUI applications already.
See "DOCUMENTATION" for API reference (and a feature overview).

Note: the code line counter doesn't count termbox code, as it is not my work (except for a few changes).