이미지에 필터적용하기.

// 세피아 톤 적용.

- (void)drawRect:(CGRect)rect
{
    // Drawing code
    UIImage *myimage = [UIImage imageNamed:@"image.jpg"];
    CIImage *cimage = [[CIImage alloc] initWithImage:myimage];
    CIFilter *sepiaFilter = [CIFilter filterWithName:@"CISepiaTone"];
    [sepiaFilter setDefaults];
    [sepiaFilter setValue:cimage forKey:@"inputImage"];
    [sepiaFilter setValue:[NSNumber numberWithFloat:0.8f] forKey:@"inputIntensity"];
   
    CIImage *image = [sepiaFilter outputImage];
    CIContext *context = [CIContext contextWithOptions:nil];
    CGImageRef cgImage = [context createCGImage:image fromRect:image.extent];
   
    UIImage *resultUIImage = [UIImage imageWithCGImage:cgImage];
   
    CGRect imageRect = [[UIScreen mainScreen] bounds];
    [resultUIImage drawInRect:imageRect];
}