ByteBufferFrameManager

```
public class ByteBufferFrameManager
extends FrameManager<Array<byte>>
                    
```
This class manages the allocation of byte buffers and Frame objects. We are interested in recycling both of them, especially byte[] buffers which can create a lot of overhead. The pool size applies to both the Frame pool and the byte[] pool - it makes sense to use the same number since they are consumed at the same time. We can work in two modes, depending on whether a BufferCallback is passed to the constructor. The modes changes the buffer behavior. 1. BUFFER_MODE_DISPATCH: in this mode, as soon as we have a buffer, it is dispatched to the BufferCallback. The callback should then fill the buffer, and finally call getFrame to receive a frame. This is used for Camera1. 2. BUFFER_MODE_ENQUEUE: in this mode, the manager internally keeps a queue of byte buffers, instead of handing them to the callback. The users can ask for buffers through getBuffer. This buffer can be filled with data and used to get a frame getFrame, or, in case it was not filled, returned to the queue using onBufferUnused. This is used for Camera2.

Nested Class Summary

Nested Classes
Modifier and Type	Class	Description
`public interface`	`ByteBufferFrameManager.BufferCallback`	Receives callbacks on buffer availability(when a Frame is released, we reuse its buffer).

Constructor Summary

Constructors
Constructor	Description
`ByteBufferFrameManager(int poolSize, ByteBufferFrameManager.BufferCallback callback)`	Construct a new frame manager.

Method Summary

Modifier and Type	Method	Description
`void`	`setUp(int format, @NonNull() Size size, @NonNull() Angles angles)`	Allocates a mPoolSize number of buffers.
`Array<byte>`	`getBuffer()`	Returns a new byte buffer than can be filled.
`void`	`onBufferUnused(@NonNull() Array<byte> buffer)`	Can be called if the buffer obtained by getBuffer was not used to construct a frame, so it can be put back into the queue.
`void`	`release()`	Releases all frames controlled by this manager andclears the pool.In BUFFER_MODE_ENQUEUE, releases also all the buffers.

Methods inherited from class com.otaliastudios.cameraview.frame.FrameManager
getFrame, getFrameBytes, getFrameDataClass, getPoolSize
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - ByteBufferFrameManager
```
ByteBufferFrameManager(int poolSize, ByteBufferFrameManager.BufferCallback callback)
```
    Construct a new frame manager.
    
    Parameters:
    
    poolSize - the size of the backing pool.
    
    callback - a callback
- Method Detail
  - setUp
```
 void setUp(int format, @NonNull() Size size, @NonNull() Angles angles)
```
    Allocates a mPoolSize number of buffers. Should be called oncethe preview size and the image format value are known.This method can be called again after release has been called.
    
    Parameters:
    
    format - the image format
    
    size - the frame size
    
    angles - angle object
  - getBuffer
```
@Nullable() Array<byte> getBuffer()
```
    Returns a new byte buffer than can be filled.This can only be called in BUFFER_MODE_ENQUEUE mode! Where the framemanager also holds a queue of the byte buffers.If not null, the buffer returned by this method can be filled and used to geta new frame through getFrame.
  - onBufferUnused
```
 void onBufferUnused(@NonNull() Array<byte> buffer)
```
    Can be called if the buffer obtained by getBuffer was not used to construct a frame, so it can be put back into the queue.
    
    Parameters:
    
    buffer - a buffer
  - release
```
 void release()
```
    Releases all frames controlled by this manager andclears the pool.In BUFFER_MODE_ENQUEUE, releases also all the buffers.