On Fri, May 2, 2008 at 3:13 AM, Graham Cox <[EMAIL PROTECTED]> wrote: > I realise these questions must sound rather fundamental, but nothing in the > Cocoa Drawing Guide or Thread Guide really addresses them. I have used > threads before to perform tasks not involving drawing, so I'm not completely > unfamiliar with them, but I haven't tried drawing on a secondary thread > before.
The reason these questions aren't addressed in the guide is because they are highly dependent on just what you are doing. Only you can determine when something needs to be updated. As for spawning multiple threads, you want your drawing to be performed really quickly. I would strongly advocate keeping a thread around for the life of your view and having it sit an a loop that ends with it performing a blocking read on some IPC port. That way it gets scheduled off the processor but you don't suffer the thread-creation or -destruction penalty every time you perform a draw. Drawing from a secondary thread isn't an easy task, so perhaps you might want to consider whether it's possible to avoid doing so. Maybe you can draw into an image on the secondary thread, and then when necessary use -performSelectorOnMainThread:withObject:waitUntilDone: to send the view a -setNeedsDisplay: message when after your thread has completed its drawing. Then the view can overwrite its own buffer with it. Be careful of synchronization issues, of course. HTH, --Kyle Sluder _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [EMAIL PROTECTED]
