Question

I am learning to program on iOS, and was learning some Core Image filters.

I learnt to use CIFilter as:

CIFilter *filter = [CIFilter filterWithName:@"CISepiaTone" keysAndValues:kCIInputImageKey, image, @"inputIntensity", [NSNumber numberWithFloat:0.8], nil];

CIFilter *filter = [CIFilter filterWithName:@"CIColorPosterize" keysAndValues:kCIInputImageKey, image, @"inputLevels", [NSNumber numberWithFloat:5.0], nil];

CIFilter *filter = [CIFilter filterWithName:@"CIPointillize" keysAndValues:kCIInputImageKey, image, @"inputRadius", [NSNumber numberWithFloat:50.0], @"inputCenter", [NSNumber numberWithFloat:50.0], nil];

When I use CISepiaTone filter, the filter works and I get a nice transformed image output. But with other two filters, I do now get any output, the ImageView is blank. Can anyone spot the problem for me? Thanks.

Answer 1

Core Image in iOS 5 doesn’t support all of the filters listed in the Core Image filters reference. You’re probably trying to use filters that aren’t supported.

[CIFilter filterNamesInCategories:nil] returns an NSArray containing the names of every available filter.