Making a UIImageView grey

Question

I\'m setting UImageViews within table cells using setImageWithUrl from the AFNetworking library, but I need the images to be greyscale... is there any way I can do this. I\'

Answer 1

I took the code from @Jesse Gumpo's example, above, but here it is as an interface.

@implementation UIImage ( Greyscale )

- (UIImage *)greyscaleImage
{
    CIImage * beginImage = [ self CIImage ] ;
    CIImage * evAdjustedCIImage = nil ;
    {
        CIFilter * filter = [ CIFilter filterWithName:@"CIColorControls" 
                                        keysAndValues:kCIInputImageKey, beginImage
                                            , @"inputBrightness", @0.0
                                            , @"inputContrast", @1.1
                                            , @"inputSaturation", @0.0
                                            , nil ] ;
        evAdjustedCIImage = [ filter outputImage ] ;
    }

    CIImage * resultCIImage = nil ;
    {
        CIFilter * filter = [ CIFilter filterWithName:@"CIExposureAdjust" 
                                        keysAndValues:kCIInputImageKey, evAdjustedCIImage
                                            , @"inputEV", @0.7
                                            , nil ] ;
        resultCIImage = [ filter outputImage ] ;
    }

    CIContext * context = [ CIContext contextWithOptions:nil ] ;
    CGImageRef resultCGImage = [ context createCGImage:resultCIImage 
                                              fromRect:resultCIImage.extent ] ;
    UIImage * result = [ UIImage imageWithCGImage:resultCGImage ] ;
    CGImageRelease( resultCGImage ) ;

    return result;
}

@end

Now you can just do this:

UIImage * downloadedImage = ... get from AFNetwork results ... ;
downloadedImage = [ downloadedImage greyscaleImage ] ;

... use 'downloadedImage' ...