CGDataProviderGetBytesAtOffsetCallback

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

Declaration

typedef size_t (*CGDataProviderGetBytesAtOffsetCallback) (
   void *info,
   void *buffer,
   size_t offset,
   size_t count
);
   

Parameters

info

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

buffer

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

offset

Specifies the relative location in the data provider at which to begin copying data.

count

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.

Overview

When Core Graphics is ready to receive data from the provider, your function is called.

For information on how to associate your function with a direct-access data provider, see CGDataProviderCreateDirectAccess and CGDataProviderDirectAccessCallbacks.

See Also

Callbacks

CGDataProviderGetBytesCallback

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

CGDataProviderReleaseInfoCallback

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

CGDataProviderRewindCallback

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

CGDataProviderSkipBytesCallback

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

CGDataProviderSkipForwardCallback

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

CGDataProviderGetBytePointerCallback

A callback function that returns a generic pointer to the provider data.

CGDataProviderReleaseBytePointerCallback

A callback function that releases the pointer Core Graphics obtained by calling CGDataProviderGetBytePointerCallback.

CGDataProviderReleaseDataCallback

A callback function that releases data you supply to the function CGDataProviderCreateWithData.

CGDataProviderGetBytesAtPositionCallback

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