Adjust Hue and Saturation of a UIImage

How to adjust Hue and Saturation of a UIImage in Objective-C. This is a method for a UIImageView subclass, but you could easily remix in another context.

- (void) changeToHue:(float)hue saturation:(float)saturation {

    UIGraphicsBeginImageContext(self.bounds.size);

    CGContextRef context = UIGraphicsGetCurrentContext();    

    UIView *hueBlend = [[UIView alloc] initWithFrame:self.bounds];

    hueBlend.backgroundColor = [UIColor colorWithHue:hue saturation:saturation brightness:1 alpha:1];

    CGContextDrawImage(context, self.bounds, self.image.CGImage);

    CGContextSetBlendMode(context, kCGBlendModeHue);

    [hueBlend.layer renderInContext:context];

    self.image = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();    

}

From my answer here.