Icon coloration at runtime

coloration.m

-(UIImage *) negativeImage
{
    UIGraphicsBeginImageContext(self.size);
    CGContextSetBlendMode(UIGraphicsGetCurrentContext(), kCGBlendModeCopy);
    [self drawInRect:CGRectMake(0, 0, self.size.width, self.size.height)];
    CGContextSetBlendMode(UIGraphicsGetCurrentContext(), kCGBlendModeDifference);
    CGContextSetFillColorWithColor(UIGraphicsGetCurrentContext(),[UIColor whiteColor].CGColor);
    CGContextFillRect(UIGraphicsGetCurrentContext(), CGRectMake(0, 0, self.size.width, self.size.height));
    UIImage *negativeImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return negativeImage;
}

- (UIImage *) imageWithWhiteBackground
{
    UIImage *negative = [self negativeImage];
    
    UIGraphicsBeginImageContext(negative.size);
    CGContextSetRGBFillColor (UIGraphicsGetCurrentContext(), 1, 1, 1, 1);
    CGRect thumbnailRect = CGRectZero;
    thumbnailRect.origin = CGPointZero;
    thumbnailRect.size.width = negative.size.width;
    thumbnailRect.size.height = negative.size.height;
    
    CGContextTranslateCTM(UIGraphicsGetCurrentContext(), 0.0, negative.size.height);
    CGContextScaleCTM(UIGraphicsGetCurrentContext(), 1.0, -1.0);
    CGContextFillRect(UIGraphicsGetCurrentContext(), thumbnailRect);
    CGContextDrawImage(UIGraphicsGetCurrentContext(), thumbnailRect, negative.CGImage);
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    
    return newImage;
}

+ (UIImage *) image:(UIImage *)image withMaskColor:(UIColor *)color
{
    UIImage *formattedImage = [image imageWithWhiteBackground];
    
    CGRect rect = {0, 0, formattedImage.size.width, formattedImage.size.height};
    UIGraphicsBeginImageContextWithOptions(rect.size, NO, 0);
    [color setFill];
    UIRectFill(rect);
    UIImage *tempColor = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    
    CGImageRef maskRef = [formattedImage CGImage];
    CGImageRef maskcg = CGImageMaskCreate(CGImageGetWidth(maskRef),
                                          CGImageGetHeight(maskRef),
                                          CGImageGetBitsPerComponent(maskRef),
                                          CGImageGetBitsPerPixel(maskRef),
                                          CGImageGetBytesPerRow(maskRef),
                                          CGImageGetDataProvider(maskRef), NULL, false);
    
    CGImageRef maskedcg = CGImageCreateWithMask([tempColor CGImage], maskcg);
    CGImageRelease(maskcg);
    UIImage *result = [UIImage imageWithCGImage:maskedcg];
    CGImageRelease(maskedcg);
    
    return result;
}