SDL-widgets

SDL-widgets is a GUI toolkit on top of the SDL libraries, written in C++. It is not especially intended for games, it is for normal applications. This implicates: a possibly complicated SDL_Surface hierarchy, where surfaces can be hidden or visible, with sliders, menus, text areas, etc. Threads are supported, communicating via messages. This is version 0.4 (june 2009).

The following widgets are provided:

push button
subwindow, canvas
radio buttons in 1 column
radio buttons in arbitrary locations
horizontal, vertical and 2-dimensional sliders
check box
horizontal and vertical scrollbar
indicator lamp
non-editable scrolling text window
dialog box
menu
ascii text
alert window

Source code with documentation: SDL-widgets-0.4.tar.gz
This also provides 3 small example audio applications. Listen to a tune created with one of them:
rising.mp3

BigBand - a program to compose music for small ensembles - has its own site:
members.chello.nl/w.boeke/bigband