Re: drawing in a separate thread

FROM : Jean-Daniel Dupas
DATE : Sat May 03 15:55:23 2008

Le 3 mai 08 à 15:30, Graham Cox a écrit :

> Cocoa already coalesces updates in this way, so when drawRect: is 
> called, the list of rects is the merged list.


Cocoa already do this for synchronous drawing, and after each 
drawRect: call it resets the list. If the drawRect: method is call 
faster than what the background thread can process, the Cocoa effort 
to coalesce updates is lost.


> I does raise a question though - is there a way to get, at any point 
> in time, the list of merged rects needing update from a view *at 
> that point* - in other words, outside of a drawRect: call, can I 
> found out what has been marked for update so far? That would be 
> useful.
>
> G.




Even if such API exists, it will be useless with multi-threading, as a 
view assume that after a drawRect: call, all rects that was marked for 
update are now updated. And so, the "dirty rects" list will not be 
synchronize with the real state of the view.