background images

At the moment, my beebclock draws the face and the hour and minute hands from scratch to an in-memory image every minute. Then it draws that image to the screen every second and then draws a line for the second hand. The only part that flickers is the second hand, which I think is acceptable. Otherwise, I think the power drain would just be too high, redrawing it all offscreen every second.

The problem is that the 240x240 buffer is a memory hog even at 1bpp. Fortunately for my watch face I only wanted 1bpp, so I can just about manage to do it in available memory.

1. The unchanging watch face in Flash
   
2. The watch face blitted from (1) with hour/minute hands, updated every minute in Flash
   
3. The in-memory offscreen buffer blitted with (2) and second hand added, and blitted to screen every second.