QLThumbnailDispatchAsync(_:_:_:)
Creates a thumbnail in the background on the provided background queue.
Declaration
func QLThumbnailDispatchAsync(_ thumbnail: QLThumbnail!, _ queue: dispatch_queue_t!, _ completion: (() -> Void)!)Parameters
- thumbnail:
The thumbnail to compute.
- queue:
The queue that’s used to create the thumbnail.
- completion:
The completion block that’s called when the thumbnail is created. The completion block is always called, even if the thumbnail computation is canceled.