CGFunction

A general facility for defining and using callback functions.

Overview

These functions can take an arbitrary number of floating-point input values and pass back an arbitrary number of floating-point output values.

Core Graphics uses CGFunctionRef objects to implement shadings. CGShading describes the parameters and semantics required for the callbacks used by CGFunctionRef objects.

Symbols

Getting the CFType ID

class var typeID: CFTypeID

Returns the type identifier for Core Graphics function objects.

Callbacks

CGFunctionEvaluateCallback

Performs custom operations on the supplied input data to produce output data.

CGFunctionReleaseInfoCallback

Performs custom clean-up tasks when Core Graphics deallocates a CGFunctionRef object.

Data Types

CGFunction

A general facility for defining and using callback functions.

CGFunctionCallbacks

A structure that contains callbacks needed by a CGFunctionRef object.