How to apply blur to a UIView?

Question

Right now I am building an iPhone app that requires blurring an entire UIView. How can I achieve this? I have seen this framework, but I don't think that works with UIView. Is there an alternate way to blur an UIView?

UPDATE: Check for my updated answer below, adding more relevance with the advent of iOS 7 and iOS 8.

Answer 1

This should work. I commented in the code to help you understand what's going on:

//To take advantage of CIFilters, you have to import the Core Image framework #import <CoreImage/CoreImage.h>  //Get a UIImage from the UIView UIGraphicsBeginImageContext(myView.bounds.size); [myView.layer renderInContext:UIGraphicsGetCurrentContext()]; UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext();  //Blur the UIImage with a CIFilter CIImage *imageToBlur = [CIImage imageWithCGImage:viewImage.CGImage];     CIFilter *gaussianBlurFilter = [CIFilter filterWithName: @"CIGaussianBlur"];  [gaussianBlurFilter setValue:imageToBlur forKey: @"inputImage"];  [gaussianBlurFilter setValue:[NSNumber numberWithFloat: 10] forKey: @"inputRadius"]; CIImage *resultImage = [gaussianBlurFilter valueForKey: @"outputImage"];  UIImage *endImage = [[UIImage alloc] initWithCIImage:resultImage];  //Place the UIImage in a UIImageView UIImageView *newView = [[UIImageView alloc] initWithFrame:self.view.bounds]; newView.image = endImage; [self.view addSubview:newView]; 

If you have any questions about the code, just leave it in the comments.

Note: CIGaussianBlur isn't present on iOS as of 5.1, so you must find a different way to blur the view for devices 5.x+ (Thanks to @BradLarson for this tip). The accepted answer in this question looks promising as a replacement, as does this library.

Answer 2

Ever since the release of iOS 7, This question has been getting a lot of hits and I thought I should follow up on what I ended up doing.

I personally blurred the picture at the time with photoshop, but there are many great third party libraries available that do dynamic and static blurring, here are a couple:

• This ingenious library takes a layer from UITabBar and applies to any view to get iOS 7's native blur: https://github.com/JagCesar/iOS-blur/
• This library is a real time blurring library that live blurs any view below it: https://github.com/alexdrone/ios-realtimeblur (as pointed out by qegal)
• Another one that does the same realtime blur: https://github.com/nicklockwood/FXBlurView
• This Library is the one I personally use and is Great, allowing you to set the tint color among other settings: https://github.com/ivoleko/ILTranslucentView

I wanted to post this because you no longer need to take screenshots of individual frames or screen.

iOS 8: With the coming release of iOS 8, Apple has included a built in blurred UIView, UIVisualEffectView (https://developer.apple.com/documentation/uikit/uivisualeffectview)