On Jun 1, 2012, at 8:23 PM, Graham Cox <graham....@bigpond.com> wrote:
> > On 02/06/2012, at 1:12 PM, Kyle Sluder wrote: > >> Give them a higher priority. You should be able to alter the priorities as >> the user scrolls, and NSOperationQueue will do the right thing. > > > I tried this but it doesn't work - a bit of thought about how the ops are > queued will show why no meaningful priority value can be assigned. > > At the moment that the operations are queued, there are some operations in > the queue not yet run, and some running. The code that creates the operations > doesn't know which ones are needed more urgently (the latest ones), so it can > only assign a high priority to all of them, so they all end up with the same > (high) priority and so we're back to square one. Maintain a mapping of objects to be previewed and the operations that generate those previews. As the user scrolls, figure out which placeholders have been scrolled on/off screen and modify the related operations' priorities appropriately. Altering a running operation's priority won't have an effect. --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: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
