Mac Developer Library


CIFilterConstructor Protocol Reference

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The CIFilterConstructor protocol defines a method for supplying CIFilter objects.

Objects implementing this protocol are called filter constructors—they produce new instances of CIFilter subclasses when filters are requested by name. You can create a filter constructor to provide new, custom filters that other Core Image clients can discover using the CIFilter class. Normally, you create and register custom filters by packaging them as Image Units (see Packaging and Loading Image Units), but you can use this protocol to provide new filters within your app that are compositions of existing filters.

To provide custom filters using this protocol, you must:

  1. Create your custom filters as CIFilter subclasses.

  2. Create a class that implements this protocol to vend instances of the appropriate CIFilter subclasses when requested.

  3. Call the CIFilter class method registerFilterName:constructor:classAttributes: for each custom filter, providing the filter’s name, an instance of your filter constructor class, and information about the filter’s attributes.

  • Returns a filter object specified by name.



    func filterWithName(_ name: String) -> CIFilter?


    - (CIFilter *)filterWithName:(NSString *)name



    The name of the requested custom filter.

    Return Value

    A CIFilter object implementing the custom filter.


    Core Image calls this method when a filter is requested by name using the CIFilter class method filterWithName: method (or related methods). Your implementation of this method should provide a new instance of the CIFilter subclass for your custom filter.


    Available in OS X v10.7 and later.