I would like to hear of a plausible and reasonable example of when a "background" app (not on the display) needs to intercept button presses.

The idea that's forming right now is to have the "active" apps show up at the top of the Hijack menu (separate from their launcher entries), and to be able to select them and thus switch to them from the menu. The Player would also be on said menu, possibly as "just another app".

Button presses go ONLY to the currently displayed app.

Each app is given a mmap'd display buffer, which they can update anytime and as often as they like (or possibly two such buffers), and Hijack displays only the data for whichever app is supposed to be displayed.

I suppose we MIGHT want an option for an app to overlay the player, but this could get very messy very quickly, so I'm not so sure. An app could just do it's own "overlay", by reading the player's display buffer and merging data from that into it's own. Still messy.

-ml