Type Alias


A callback function that copies from a provider data stream into a Core Graphics buffer.


typealias CGDataProviderGetBytesCallback = (UnsafeMutableRawPointer?, UnsafeMutableRawPointer, Int) -> Int



A generic pointer to private data shared among your callback functions. This is the same pointer you supplied to CGDataProviderCreate.


The Core Graphics buffer into which you copy the specified number of bytes.


The number of bytes to copy.

Return Value

The number of bytes copied. If no more data can be written to the buffer, you should return 0.


When Core Graphics is ready to receive data from the provider data stream, your function is called. It should copy the specified number of bytes into buffer.

For information on how to associate your callback function with a data provider, see CGDataProviderCreate and CGDataProviderCallbacks.

See Also

Creating Sequential-Access Data Providers

struct CGDataProviderSequentialCallbacks

Defines a structure containing pointers to client-defined callback functions that manage the sending of data for a sequential-access data provider.

typealias CGDataProviderRewindCallback

A callback function that moves the current position in the data stream back to the beginning.

typealias CGDataProviderSkipForwardCallback

A callback function that advances the current position in the data stream supplied by the provider.

typealias CGDataProviderReleaseInfoCallback

A callback function that releases any private data or resources associated with the data provider.