Question

I’ve got a gaussian blur which I’m doing for an app.

    //Get a UIImage from the UIView
    UIGraphicsBeginImageContext(self.view.bounds.size);
    [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    //Blur the UIImage
    CIImage *imageToBlur = [CIImage imageWithCGImage:viewImage.CGImage];
    CIFilter *gaussianBlurFilter = [CIFilter filterWithName:@"CIGaussianBlur"];
    [gaussianBlurFilter setValue:imageToBlur forKey:@"inputImage"];
    [gaussianBlurFilter setValue:[NSNumber numberWithFloat:2] forKey:@"inputRadius"];
    CIImage *resultImage = [gaussianBlurFilter valueForKey:@"outputImage"];
    UIImage *endImage = [[UIImage alloc] initWithCIImage:resultImage];

    //Place the UIImage in a UIImageView
    newView = [[UIImageView alloc] initWithFrame:self.view.bounds];
    newView.image = endImage;
    [self.view addSubview:newView];

It works great, but I want to be able to reverse it and return the view back to normal.

How can I do this as trying to simply remove the blur’s view from it’s superview didn’t work. I’ve also tried setting various properties to nil with no luck.

Answer 1

Keep a pointer to viewImage in a property

@property (nonatomic, strong) UIImage* originalImage;

then after

UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();

add

self.originalImage = viewImage;

To revert your image:

newView.image = self.originalImage;

when you apply the blur it does not alter viewImage.. you have created a separate CIImage which gets blurred, and you make a new UIImage from the blurred CIImage.