# CAMERA_I2CAutoWhiteBalance*

## Syntax

  `#include <twl/camera.h>`
  `CAMERAResult CAMERA_I2CAutoWhiteBalance(CAMERASelect camera, BOOL on);`
  `CAMERAResult CAMERA_I2CAutoWhiteBalanceAsync(CAMERASelect camera, BOOL on, CAMERACallback callback, void *arg);`

## Arguments

camera | Camera to configure (`CAMERA_SELECT_IN`, `CAMERA_SELECT_OUT`, or `CAMERA_SELECT_BOTH`).
on | If `TRUE`, the auto-adjustment feature is enabled. If `FALSE`, it is disabled.
callback | Function that is called when asynchronous processing has completed.
arg | Arguments when the callback function is invoked.

## Return Values

Returns `CAMERA_RESULT_SUCCESS` if configuration was successful.

## Description

Enables or disables the auto-adjustment feature for the camera's white balance when it is set to "auto" with `CAMERA_WHITE_BALANCE_NORMAL`. The exposure value is unstable immediately after the camera is started with the `CAMERA_I2CActivate` function. A value of `INVALID_COMMAND` is returned if `CAMERA_WHITE_BALANCE_NORMAL` is not set. Calling the `CAMERA_I2CWhiteBalance` function resets the value set by this function and enables the auto-adjustment feature.
Unlike `CAMERA_I2CAutoWhiteBalance`, the `CAMERA_I2CAutoWhiteBalanceAsync` function returns control immediately and runs asynchronously. Use callback to confirm that processing has completed.
Note:
If camera settings are changed using any of the `CAMERA_I2C*` functions, the changes may be delayed for approximately one frame before they are applied. If camera settings are changed during image capture, therefore, an application's timing may make it impossible to get an image with the changes applied.
Occasional Shifting of Captured Images
The captured image may shift if this function is called during image capture.
Before calling this function, first stop the image capture with `CAMERA_StopCapture`. Then call this function. After this function completes execution, restart the image capture with `CAMERA_StartCapture`.

## See Also

`CAMERASelect`
`CAMERACallback`
`CAMERAResult`

## Revision History

2009/11/11 Explained occasional shifting of captured images.
2009/03/25 Added information about changing camera settings during capture operations.
2008/10/30 Added that `CAMERA_SELECT_BOTH` can also be specified.
2008/08/22 Initial version.

CONFIDENTIAL