How do handle page frame timing when not using a game framework?

If you don't use cocoa2d etc., how would you control the speed of a frame if you had to code this manually?

i.e. if you wanted things to operate in 50 fram开发者_运维问答es per second (or whatever the industry best practice is?)

use CADisplayLink to get called at every frame. It will be max 60 FPS. If your code do too much work, you'll be called less often, and your UI will feel slow below 40 FPS.

Alternative is to schedule NSTimers, but it has some issues. If your runloop is not ready to call the timer on time, calls will be skipped, thus not guaranteeing any frame rate.

from apple's doc

A repeating timer always schedules itself based on the scheduled firing time, as opposed to the actual firing time. For example, if a timer is scheduled to fire at a particular time and every 5 seconds after that, the scheduled firing time will always fall on the original 5 second time intervals, even if the actual firing time gets delayed. If the firing time is delayed so far that it passes one or more of the scheduled firing times, the timer is fired only once for that time period; the timer is then rescheduled, after firing, for the next scheduled firing time in the future.