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Editorial Team
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Asked: 2026-06-11T10:28:35+00:00

I am using the followinf code for applying image filters. This is working fine

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I am using the followinf code for applying image filters. This is working fine on scaled down images.
But when I apply more than 2 filters on full resolution images, the app crashes. A memory warning is received.

When I open the ‘allocations’ instrument, I see that CFData(store) takes up most of the memory used by the program.
When I apply more than 2 filters on a full resolution image, the ‘overall bytes’ go upto 54MB. While the ‘live bytes’ don’t seem to reach more than 12MB when I use my eyes on the numbers as such, but the spikes show that live bytes also reach upto this number and come back.

Where am i going wrong?

- (UIImage *)editImage:(UIImage *)imageToBeEdited tintValue:(float)tint 
{ 
CIImage *image = [[CIImage alloc] initWithImage:imageToBeEdited]; 
NSLog(@"in edit Image:\ncheck image: %@\ncheck value:%f", image, tint); 

[tintFilter setValue:image forKey:kCIInputImageKey]; 
[tintFilter setValue:[NSNumber numberWithFloat:tint] forKey:@"inputAngle"]; 

CIImage *outputImage = [tintFilter outputImage]; 
NSLog(@"check output image: %@", outputImage); 
return [self completeEditingUsingOutputImage:outputImage]; 
} 

- (UIImage *)completeEditingUsingOutputImage:(CIImage *)outputImage 
{ 
CGImageRef cgimg = [context createCGImage:outputImage fromRect:outputImage.extent]; 
NSLog(@"check cgimg: %@", cgimg); 
UIImage *newImage = [UIImage imageWithCGImage:cgimg]; 
NSLog(@"check newImge: %@", newImage); 
CGImageRelease(cgimg); 
return newImage; 
}

Edit:
I also tried making cgimg as nil. Didn’t help.
I tried putting context declaration and definition inside the 2nd function. Didn’t help.
I tried to move declarations and definitions of filters inside the functions, didn’t help.

AlsoCrash happens at

CGImageRef cgimg = [context createCGImage:outputImage fromRect:outputImage.extent];
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1 Answer

  1. Editorial Team

    the cgimg i was making took most of the space in memory and was not getting released.

    I observed that calling the filer with smaller values takes the CFData (store) memory value back to a samller value, thus avoiding the crash.

    So I apply filter and after that call the same filter with image as ‘nil’. This takes memory back to 484kb or something from 48 MB after applying all 4 filters.

    Also, I am applying this filters on a background thread instead of the main thread. Applying on main thread again causes crash. Probably it doesn’t get enough time to release the memory. I don’t know.
    But these things are working smoothly now.

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