Question

I’d like to create a CoreImage filter chain, and to be able to control the “intensity” of each filter in the chain by compositing its individual effect with alpha, or opacity settings, but I am not seeing a way to composite with alpha or opacity in the docs.

I could jump out of Core image filter chain and composite with a core graphics context I guess.

Answer 1

Ended up doing it like this. Code from this answer: https://stackoverflow.com/a/3188761/1408546

UIImage *bottomImage = inputImage;
UIImage *image = filterOutput;
CGSize newSize = CGSizeMake(inputImage.size.width, inputImage.size.height);
UIGraphicsBeginImageContext( newSize );
[bottomImage drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height) blendMode:kCGBlendModeNormal alpha:_opacity];
UIImage *blendedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();