How to efficiently and fast blur an image on the iPhone?

Question

If I have a UIImage or CGContextRef or the pure bitmap data (direct access to decompressed ARGB-8 pixels), what\'s my best option to blur an image with radius 10 pixels as fast

Answer 1

I've implemented a stackBlur algorithm for iOS, which is close to GaussianBlur but very fast:

https://github.com/tomsoft1/StackBluriOS

Check for instance here:

Blur an UIImage on change of slider