Libsx -- the Simple X library -- is a lightweight wrapper library sitting on top of the Athena Widget set, as implemented in Xaw and variants (Xaw95 yields much nicer results than Xaw in comination with libsx). Libsx does not compete with GTK or Qt, but nevertheless allows you to write a lot of small (or bigger) programs painlessly, with no or little knowledge of X programming. With libsx, writing a simple program that opens a window, has a few buttons, and draws some graphics (lines, circles, bitmaps, etc.) is a matter of 5-10 lines of code, including the drawing code. Hello World is 2 lines. More complicated programs that respond to mouse clicks, have buttons, scrollbars, file browsers, a color selector, etc., can be written in 25-50 lines of code.
