Status / progress indicator

Statusbar is a simple GUI to display the progress of a lengthy computation. It displays the current state and the elapsed time as well as the estimated time to finish.

On confirmation, the user can interrupt the computation by closing the window. At every update, the application program is signaled if it should stop or continue.

Statusbar minimizes processor load by updating only if either the elapsed time or the progress changed (i.e. at most once per second or 0.4% advance).