Very slow UIImage blurring on iOS

Question

I would like to apply blur on my image view. I have this code for blurring:

- (UIImage *)applyBlurOnImage: (UIImage *)imageToBlur withRadius: (CGFloat)blurRadius
{
    CIImage *originalImage = [CIImage imageWithCGImage: imageToBlur.CGImage];
    CIFilter *filter = [CIFilter filterWithName: @"CIGaussianBlur" keysAndValues: kCIInputImageKey, originalImage, @"inputRadius", @(blurRadius), nil];
    CIImage *outputImage = filter.outputImage; CIContext *context = [CIContext contextWithOptions:nil];
    CGImageRef outImage = [context createCGImage: outputImage fromRect: [outputImage extent]];
    return [UIImage imageWithCGImage: outImage];
}

But blurring happens very slow for screenshot of my UIView on iPad.

Is there any faster way to do this?

possible duplicate of [Fast blur on iOS](http://stackoverflow.com/questions/12271016/fast-blur-on-ios) — pNre, Apr 08 '14 at 11:37

Rafał Sroka · Accepted Answer · 2014-04-08T11:52:05.757

7

Apple released code at WWDC that does what you need.

It is a category on UIImage and uses the Accelerate framework for fast image processing. If you have a developer account you can grab the UIImage category here.

edited Apr 08 '14 at 11:52

answered Apr 08 '14 at 11:43

Rafał Sroka

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Did they really release it at WWDC? I remember it wasn't really there for quite some time after the presentation (I think the blur was only on the UIToolbar or whatnot..). But hey, that's awesome! – Michal Apr 08 '14 at 11:51

score 1 · Answer 2 · edited May 23 '17 at 10:28

1

Try this library. It is fairly new and quite fast. Remember that blur is either way quite nasty thing for the device to process, so it won't be zen-like, but it's very good.

OR - you can refer to this question that has some high quality answers.

edited May 23 '17 at 10:28

Community

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answered Apr 08 '14 at 11:43

Michal

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Very slow UIImage blurring on iOS

2 Answers2