Blur isn't applied on background view until it's rendered onto screen

[KiranPanesar]

So I wanted to show a KVNProgress HUD as soon as a view controller's view appears on the screen, so the user can only see the blurred overlay.

Right now if you call [KVNProgress show] is anything other than the -viewDidAppear, the HUD's background is totally transparent.

I would suggest listening to the view's properties to determine when its visibility changes and redraw the blur when that happens. Open to here other ideas.

[kevin-hirsch]

It is because it's a static blur based on a screenshot of the view. In your case, the view is not yet visible so this causes the issue you have. It's planned that I implement also a dynamic blur, so I'll keep you in touch from here when it's done ;)

[KiranPanesar]

Yeah, I thought that was the case.

A possibility for iOS 8+ would be UIBlurEffect:
https://developer.apple.com/library/prerelease/ios/documentation/UIKit/Reference/UIBlurEffect_Ref/index.html

[kevin-hirsch]

Yes, that what I was thinking for iOS 8, but I will have to find another solution for iOS 7 compatibility.

[KiranPanesar]

We have implemented UIBlurEffect for iOS 8 on our internal projects and we're exploring GPUBlur and other hardware accelerated options for iOS 7 support.

We're going to be working on that at the end of next week, so if we find a good hardware-accelerated live blur method for our projects, I will share it here!

[kevin-hirsch]

Thanks a lot! 👍