full-screen background image

@FransM,

it all depends... how you go for it. But yes, memory is a factor as well as the processing.

Unfortunately, you can go only once every minute after the plain image in the store and for performance it is best to know the bounding boxes of your hands.

Let's have a walk thru the sencarios:

1. ---event: watch turns on
   
2. draw image from store
   
3. draw hour hand
   
4. remember hour hand bounding box
   
5. draw minute hand
   
6. remember minute hand bounding box
   
7. calculate bounding box of second hand
   
8. capture image in second hand bounding box from display buffer and save it for restore when second hand has to change
   
9. draw second hand
   
10. --- event: second hand changes to non-full-minute value (any from 1 thru 59)
    
11. restore saved data to restore current image of passed second
    
12. resume at 7.
    
13. --- event: second hand changes to full-minute value (0)
    
14. restore saved data to restore current image of passed second
    
15. restore minute hand bounding box from storage
    
16. restore hour hand bounding box from storage
    17 resume at 3.
    
    

You can optimize 14, 15 and 16 to draw overlaps of all three bounding boxes only once.... give most relieve for 2:07 and :08, 4:22 and :23, 7:37 and:38 and 10:52 and :53.