On Tue, Dec 20, 2016, at 08:59 AM, Andreas Falkenhahn wrote: > So everybody knows that all things relating to UIKit have to be done > on the main thread. > > But what about AVFoundation functions which bear some resemblance to > UIKit APIs? Do these have to be called on the main thread too or can > they also be called from a worker thread? > > For example, when adding an AVPlayerLayer to a view using addSubview() > I have to do this on the main thread of course. > > But what about changing the frame size of an AVPlayerLayer using > setFrame()? AVPlayerLayer inherits from CALayer which is part of the > QuartzCore framework, not UIKit. But of course CALayer methods like > setFrame() bear a strong resemblance to their UIKit counterparts so > I'm wondering whether it is really allowed to call setFrame() from > a worker thread?
Since AVPlayerLayer is a layer, not a view, it cannot be added with addSubview. It can either be added as a sublayer to your view’s layer, or it can be wrapped in a view and *that view* added as a subview. The distinction is important in many ways, but in this case the answer is the same for both: don’t do this from a background thread. (Caveat: it is technically possible to do CALayer-level work on a background thread, but you have to manage many aspects of the CATransaction yourself. It’s not easy to do correctly, and it gets _very_ complex when manipulating a layer tree from multiple threads simultaneously. And as soon as one of these layers belongs to a view, you must only touch it from the main thread.) --Kyle Sluder > > Also, what about AVPlayerLayer methods like removeFromSuperlayer()? > Is this main thread only as well? _______________________________________________ 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
