Hello! Faced the problem of heavy CPU utilization when using CIFilter and UISlider.
Tell me, please, what could be the problem. Code m file:

@implementation ViewController UIImageView *imageView; UIImage *endImg; CIImage *outImgFilter; -(void) slChange:(id)sender{ UISlider *slider = (UISlider *)sender; CIImage *outImg = [[CIImage alloc] initWithImage:[UIImage imageNamed:@"derevo.jpg"]]; CIFilter *invertColor = [CIFilter filterWithName:@"CIColorControls"]; [invertColor setValue:outImg forKey:@"inputImage"]; [invertColor setValue:[NSNumber numberWithFloat:slider.value] forKey:@"inputSaturation"]; outImgFilter = [invertColor outputImage]; endImg = [UIImage imageWithCIImage:outImgFilter]; [imageView setImage:endImg]; } -(void)viewDidLoad{ [super viewDidLoad]; UISlider *slider = [[UISlider alloc] init]; slider.frame = CGRectMake(10, 25, 150, 20); [slider addTarget:self action:@selector(slChange:) forControlEvents:UIControlEventValueChanged]; slider.minimumValue = 0; slider.maximumValue = 8; slider.value = 0; [self.view addSubview:slider]; NSString *imagePath = @"derevo.jpg"; imageView = [[UIImageView alloc] initWithFrame:CGRectMake(10, 100, 355, 355)]; imageView.image = [UIImage imageNamed:imagePath]; [self.view addSubview:imageView]; } -(void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; // Dispose of any resources that can be recreated. } @end

    1 answer 1

    Stumbled upon an interesting article . Hope to help you.

    In terms of CIFilter, I do not know how to improve its speed. Really slow. I did not use it for real-time rendering.