IOS image processing-fuzzy images

IOS image processing-fuzzy images

Solution:Blur an image

Prerequisites:Add CoreGraphics. framework

Source code:

- (UIImage*) blur:(UIImage*)theImage{    // create our blurred image    CIContext *context = [CIContext contextWithOptions:nil];    CIImage *inputImage = [CIImage imageWithCGImage:theImage.CGImage];        // setting up Gaussian Blur (could use one of many filters offered by Core Image)    CIFilter *blurFilter = [CIFilter filterWithName:@"CIGaussianBlur"];    [blurFilter setValue:inputImage forKey:kCIInputImageKey];    [blurFilter setValue:[NSNumber numberWithFloat:10.0f] forKey:@"inputRadius"];    CIImage *result = [blurFilter valueForKey:kCIOutputImageKey];        // CIGaussianBlur has a tendency to shrink the image a little,    // this ensures it matches up exactly to the bounds of our original image    CGImageRef cgImage = [context createCGImage:result fromRect:[inputImage extent]];        UIImage *returnImage = [UIImage imageWithCGImage:cgImage];    //create a UIImage for this function to "return" so that ARC can manage the memory of the blur...    //ARC can't manage CGImageRefs so we need to release it before this function "returns" and ends.    CGImageRelease(cgImage);//release CGImageRef because ARC doesn't manage this on its own.        return returnImage;}

Problem:Because the edges become translucent during blur, the ideal situation is that the original image can be properly enlarged and CIAffineClamp can be used to process the image before blurring.

Source code:

- (UIImage*) blur:(UIImage*)theImage{    // create our blurred image    CIContext *context = [CIContext contextWithOptions:nil];    CIImage *inputImage = [CIImage imageWithCGImage:theImage.CGImage];        CIFilter *affineClampFilter = [CIFilter filterWithName:@"CIAffineClamp"];    CGAffineTransform xform = CGAffineTransformMakeScale(1.0, 1.0);    [affineClampFilter setValue:inputImage forKey:kCIInputImageKey];    [affineClampFilter setValue:[NSValue valueWithBytes:&xform                                               objCType:@encode(CGAffineTransform)]                                                 forKey:@"inputTransform"];        CIImage *extendedImage = [affineClampFilter valueForKey:kCIOutputImageKey];        // setting up Gaussian Blur (could use one of many filters offered by Core Image)    CIFilter *blurFilter = [CIFilter filterWithName:@"CIGaussianBlur"];    [blurFilter setValue:extendedImage forKey:kCIInputImageKey];    [blurFilter setValue:[NSNumber numberWithFloat:10.0f] forKey:@"inputRadius"];    CIImage *result = [blurFilter valueForKey:kCIOutputImageKey];        // CIGaussianBlur has a tendency to shrink the image a little,    // this ensures it matches up exactly to the bounds of our original image    CGImageRef cgImage = [context createCGImage:result fromRect:[inputImage extent]];        UIImage *returnImage = [UIImage imageWithCGImage:cgImage];    //create a UIImage for this function to "return" so that ARC can manage the memory of the blur...    //ARC can't manage CGImageRefs so we need to release it before this function "returns" and ends.    CGImageRelease(cgImage);//release CGImageRef because ARC doesn't manage this on its own.        return returnImage;}

Reference: (online resources, some links are lost)

Http://stackoverflow.com/questions/12839729/correct-crop-of-cigaussianblur