Screen refresh question

[cyrille de brébisson]

Hello,

Multiple answers there...
- Backbuffers:
The problem with drawing in a back buffer is that this assumes basicaly instant drawing. Althrough this is the case most of the time, it is not always the case. Some calculations are slow (or very slow, or even never ends). Using a backbuffer do draw would cause in these cases a 'wait for it to draw' syndrom instead of a 'you see it draw effect'. It would also affect user programs that interract with the screen

- Selective redraw after key presses
The HP48 had such a system in place. And it was one of the hardest thing that the team did and one of the place where they had the most numbers of bugs. It was essencial to do it on the 48 which was (at least originally so slow), so they had no other choices. However, since prime is fast, it was not nessecary to do it, so we spent our time on other places of the system.


- We are working on it.
If you compare prime now with olders revision, you will see that there is less and less flickering happening. This is because we are (selectively) adding the use a backbuffer for drawing. But this is done on a per control basis, not on a system wide basis.

Cyrille