Since iOS 7, Core Image contains several generators for 2D barcodes. While I was writing my book Barcodes and iOS, only the CIQRCodeGenerator was documented. Apple’s standard policy is that classes which are not documented are to be considered off limites. Seeking clarification, I emailed an Apple evangelist and he confirmed that this is still the case.
So I mentioned the three other – undocumented – Core Image filters in the chapter about barcode generation, but cautioned the reader about their usage in app store apps: CIAztecCodeGenerator, CIPDF417BarcodeGenerator and CICode128BarcodeGenerator. At WWDC 2015, I learned that my assumption as well as the evangelist’s confirmation were incorrect.