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Quartz Core Framework Reference CIFilterGenerator Class Reference

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CIFilterGenerator

The CIFilterGenerator class provides methods for creating a CIFilter object by chaining together existing CIFilter objects to create complex effects. (A filter chain refers to the CIFilter objects that are connected in the CIFilterGenerator object.) The complex effect can be encapsulated as a CIFilterGenerator object and saved as a file so that it can be used again. The filter generator file contains an archived instance of all the CIFilter objects that are chained together.

Any filter generator files that you copy to /Library/Graphics/Image Units/ are loaded when any of the loading methods provided by the CIPlugIn class are invoked. A CIFilterGenerator object is registered by its filename or, if present, by a class attribute that you supply in its description.

You can create a CIFilterGenerator object programmatically, using the methods provided by the CIFilterGenerator class, or by using the editor view provided by Core Image (see CIFilter Image Kit Additions).

  • Creates and returns an empty filter generator object.

    Declaration

    Objective-C

    + (CIFilterGenerator *)filterGenerator

    Return Value

    A CIFilterGenerator object.

    Discussion

    You use the returned object to connect two or more CIFilter objects and input images. It is also valid to have only one CIFilter object in a filter generator.

    Availability

    Available in OS X v10.5 and later.

  • Creates and returns a filter generator object and initializes it with the contents of a filter generator file.

    Declaration

    Objective-C

    + (CIFilterGenerator *)filterGeneratorWithContentsOfURL:(NSURL *)aURL

    Parameters

    aURL

    The location of a filter generator file.

    Return Value

    A CIFilterGenerator object; returns nil if the file can’t be read.

    Availability

    Available in OS X v10.5 and later.

  • Archives a filter generator object to a filter generator file.

    Declaration

    Swift

    func writeToURL(_ aURL: NSURL, atomically flag: Bool) -> Bool

    Objective-C

    - (BOOL)writeToURL:(NSURL *)aURL atomically:(BOOL)flag

    Parameters

    aURL

    A location for the file generator file.

    flag

    Pass true to specify that Core Image should create an interim file to avoid overwriting an existing file.

    Return Value

    Returns true if the the object is successfully archived to the file.

    Discussion

    Use this method to save your filter chain to a file for later use.

    Availability

    Available in OS X v10.5 and later.

  • Registers the name associated with a filter chain.

    Declaration

    Swift

    func registerFilterName(_ name: String)

    Objective-C

    - (void)registerFilterName:(NSString *)name

    Parameters

    name

    A unique name for the filter chain you want to register.

    Discussion

    This method allows you to register the filter chain as a named filter in the Core Image filter repository. You can then create a CIFilter object from it using the the filterWithName: method of the CIFilter class.

    Availability

    Available in OS X v10.5 and later.

  • Creates a filter object based on the filter chain.

    Declaration

    Swift

    func filter() -> CIFilter

    Objective-C

    - (CIFilter *)filter

    Return Value

    A CIFilter object.

    Discussion

    The topology of the filter chain is immutable, meaning that any changes you make to the filter chain are not reflected in the filter. The returned filer has the input an output keys that are exported.

    Availability

    Available in OS X v10.5 and later.

  • Keys for the exported parameters of a filter generator object.

    Declaration

    Swift

    let kCIFilterGeneratorExportedKeyName: String let kCIFilterGeneratorExportedKey: String let kCIFilterGeneratorExportedKeyTargetObject: String

    Objective-C

    extern NSString *const kCIFilterGeneratorExportedKey; extern NSString *const kCIFilterGeneratorExportedKeyTargetObject; extern NSString *const kCIFilterGeneratorExportedKeyName;

    Constants

    • kCIFilterGeneratorExportedKeyName

      kCIFilterGeneratorExportedKeyName

      The key (CIFilterGeneratorExportedKeyName) for the name used to export the CIFilterGenerator object. The associated value is a string that specifies a unique name for the filter generator object.

      Available in OS X v10.5 and later.

    • kCIFilterGeneratorExportedKey

      kCIFilterGeneratorExportedKey

      The key (CIFilterGeneratorExportedKey) for the exported parameter. The associated value is the key name of the parameter you are exporting, such as inputRadius.

      Available in OS X v10.5 and later.

    • kCIFilterGeneratorExportedKeyTargetObject

      kCIFilterGeneratorExportedKeyTargetObject

      The target object (CIFilterGeneratorExportedKeyTargetObject) for the exported key. The associated value is the name of the object, such as CIMotionBlur.

      Available in OS X v10.5 and later.