iOS animate a blur for a view

Question

I would like to quickly animate a blur on a UIView to use as a transition in my app. I'm having trouble knowing where to start. I believe core image is the proper tool for the job. Can anyone point me to a sample of how to blur a UIView? I'm assuming I will need to convert the view into a single UIImage, but I don't know where to proceed from there.

Thanks in advance!

Answer 1

Taking a snapshot of the View and using GPUImage from Brad Larson (the GPUImageGaussianBlurFilter) got me some nice results.

To animate the view I created a ImageView with the blurred image and animated the alpha channel from 0 to 1 to make the blur appear progressively.

Alternatively, I presume its possible to increase the blursize per frame.

#import "GPUImage.h"
...
[view.layer renderInContext:UIGraphicsGetCurrentContext()];
...
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
...
GPUImageGaussianBlurFilter * filter = [[GPUImageGaussianBlurFilter alloc] init];
filter.blurSize = 0.5;
UIImage * blurred = [filter imageByFilteringImage:image];