Question

Possible Duplicate:
Safe way to render UIVIew to an image on background thread?

I am trying to implement some HUD code. The HUD is and activity indicator to give some feedback to users during long operations of course. As I understand it, the HUD must be run on the main thread, as it it a UI operation, but I also understand that if other operations are a UI operation they also needs to run on the main thread. I assume running CoreImage filters (for instance) would be an example of something that could be run off the main thread, but adding the resultant UIImages images to UIImageView would need to be run on the main thread. Am I correct? What about [[aView layer] renderInContext:UIGraphicsGetCurrentContext()]? Can this be run off the main thread?

How can I determine exactly which operations need to be run on the main thread?

Thanks for reading.

Answer 1

What about [[aView layer]
renderInContext:UIGraphicsGetCurrentContext()]? Can this be run off
the main thread?

What is a view? It’s part of the interface. What is a layer? It’s part of the interface. Don’t touch the interface except in the main thread.