On 19.06.2011, at 14:46, Matthias Arndt wrote: > 1. Sleeping the drawing loop in drawRect: (or make the runLoop wait for some > time) and use [... flushGraphics]: Freezes the GUI, as the app is > single-threaded
sleep() will block the thread you're in. That's never a good idea (unless the alternative would be a tight loop doing nothing ...). It's always a better idea to handle pauses by registering for a callback of some sort at a later time, then doing your work in there. That way the system is free to do other things in the meantime, like process events. > 2. Moving the drawing in a 2nd thread and then pause this one: AFAIK is > drawing in a second thread not allowed in Cocoa Sure drawing from a second thread is allowed. Quartz is pretty much thread-safe. But there are some limits on what you can do from inside an NSView. But you'e free to e.g. create an NSImage in another thread, draw into that, then hand that off to the main thread which would then actually draw it to the screen. So you could draw a partial image, then make a copy, hand that off to the main thread asynchronously and continue drawing onto the original, handing off more copies as needed. Although depending on how many animation steps we're talking that may not perform well either. > 3. Limit the drawing loop to an increasing high bound, and setup a timer to > fire [self setNeedsDisplay:YES] periodically: Causes the first x paths being > redrawn at each animation step, resulting in a bad performance You mean the first time would draw 1 … 100. The next would draw 1 … 100 and 100 … 200 ? So 1 … 100 gets drawn twice … ? > 4. Same approach, but skipping the first x paths in the next animation step: > Corrupted display, e. g. while resizing in an animation Yeah. You definitely need to keep some state (e.g. in an ivar) that knows how much should be drawn on a redraw. My NSImage-based approach would take care of this problem because the "current" animation image would always be there, and you could just redraw that. Of course, if your window gets resized, you may have a smaller image than your view size, but only until the next animation step, so you could probably just draw it in the right position and draw a pattern (like Maps.app on the iPhone does it) in the empty areas in the meantime. Cheers, -- Uli Kusterer "The Witnesses of TeachText are everywhere..." http://www.zathras.de _______________________________________________ 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 arch...@mail-archive.com
